preview all symposia



Materials for energy storage, production & harvesting applications

Fifty years ago, it was forecast that our modern society would be supported and operated mainly by three elements of technology; i.e. materials, energy and information. Rapid rise in the research and development of new materials has not only largely improved our modern life but also controls further expansions of the other two technologies. The research of materials, such as more efficient batteries and light chemical energy conversion materials, is urgently required. Our symposium will be one such attempt in the field of energy research.


The growth of the human population coupled with the simultaneous improvement of living conditions is resulting in a rapidly rising global energy demand, and the negative effects on the environment in the form of pollution and global warming are becoming ever more apparent. Therefore, it is of utmost importance to take action now and concentrate on an active search for alternatives to our current fossil fuel based economy. The general consensus is that only renewable energies could provide a long-term sustainable source of energy. One needs, however, to consider that if fossil fuel is taken out of the picture, one requires an adequate substitute energy carrier for mobile applications (cars, planes, etc.). Our symposium will focus on novel materials that have attracted the focus of the scientific community in the vast field of energy materials. The applications of such materials will be having a broad view in the area of solar cell, photocatalytic water splitting, super capacitor, battery, thermoelectrics, hydrogen storage and fuel cells. Scientists doing their research in all the above area will be a getting a common platform to showcase their latest findings, which all will be attached through a common string named Energy.  For example, for the super capacitors, the range of topics will include capacitor performances for power uses such as electric vehicles, energy back-up applications, and renewable energy storage systems. Materials (such as, including but not limited to carbonaceous materials, intercalation compounds, metal oxides, nitrides, molybdates, phosphates, polymers and other composites) for electrochemical double layer, hybrid, redox, symmetric and asymmetric capacitor systems will also be included. The symposium will be a mixture of theory and experiments with a strong view of bridging the gap between them. The choice of materials is having a wide range from oxide materials to recently synthesized transition metal di- chalcogenides and dimension-wise they can be in bulk, surface, monolayer phase or in form of hetero- structures and nano-composits.

The following topics both in the field of theory and experiments will be covered in the symposium:

  • Capacitor Technology
  • Novel materials for enhance battery performance
  • Perovskite based materials for solar cell
  • Two-dimensional materials for energy production and storage
  • Application of Diamond in Energy Research
  • Oxide materials and their application in energy research
  • Photocatalytic materials for hydrogen production
  • Materials for hydrogen storage
  • Fuel Cells
  • Thermoelectrics
  • Heterostructured nano-materials and nanocomposits

List of invited speakers:

  • Chris G. Van de Walle, University of California, USA
  • Priya Vashishta,  University of Southern California,  USA
  • Charlotte Platzer Björkman, Uppsala University, Sweden
  • Lin Zhang, IFW Dresden, Germany
  • Seokwoo Jeon, KAIST, South Korea
  • Howon Jang, Seoul National University, South Korea
  • Soo Young Kim, Chungang University, South Korea
  • Ladislav Kavan, J. Heyrovsky Institute of Physical Chemistry, Czech Republic
  • Marketa Zukalova, J.Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech Republic
  • Eva Majkova, Slovakia
  • Won-Sub Yoon, Sungkyunkwan University, South Korea
  • Byoungwoo Kang, Postech, South Korea
  • Sang Young Lee, UNIST, South Korea
  • Myung-Jin Lee, SAIT, South Korea
  • Robert Dominqo, National Institute of Chemistry, Laboratory for Materials Electrochemistry, Slovenia
  • Yan Yu, University of Science and Technology of China, China
  • Xiaobo Ji, Central South University, China
  • Raphael Janot,  CNRS Researcher at LRCS, France
  • Drew Parsons, Murdoch University, Australia
  • Enn Lust, University of Tartu, Finland
  • Anji Reddy, Karlsruhe Institute of Technology, Germany
  • Sheigeto Okada, Kyushu University, Japan
  • Mariko Matsunaga , Chuo University, Japan
  • Craig Fisher, Japan Fine Ceramics Center, japan
  • Jong-Song Yu, Daegu Gyeongbuk Institute of Science and Technology, South Korea
  • M K Devaraju, University of South Australia, Australia
  • Andréia Luísa da Rosa, Universidade Federal de Goiás, Brazil
  • Petra E. de Jongh, Utrecht University, The Netherlands
  • Gueorgui K. Gueorguiev, Linkoping University, Sweden
  • Kondo-Francois Aguey-Zinsou, University of New South Wales, Australia
  • Xue Jiang, Dalian University of Technology, China
  • Mathieu Salanne, Université Pierre et Marie Curie, France
  • Jeha Kim, Cheongju University, South Korea
  • Anja Bieberle-Hütter, Dutch Institute for Fundamental Energy Research, The Netherlands

Tentative list of scientific committee members

  • T. K. Kang
  • K. V.Rao
  • B. Johansson
  • C.G. Granqvist
Start atSubject View AllNum.Add
Authors : Chris G. Van de Walle
Affiliations : Materials Department, University of California, Santa Barbara, California, USA

Resume : Perovskite oxides can exhibit high proton conductivity and are promising electrolyte materials for solid oxide fuel cells (SOFCs). Proton-conducting electrolytes can operate at far lower temperatures than traditional materials that rely on migration of oxygen. Zirconate-based perovskites exhibit high chemical stability and are among the most promising electrolytes for SOFCs. We study proton conductivity in SrZrO3 (SZO) and how it is impacted by point defects and impurities. In undoped SZO, the defect chemistry is dominated by oxygen vacancies and strontium vacancies [1]. Acceptor doping with Sc or Y at the Zr site affects the defect concentrations and impacts the proton solubility and diffusion. If the dopant impurity substitutes at the Sr site instead of the Zr site, it will act as a donor, with detrimental consequences [2]. I will discuss strategies for optimizing doping and proton conductivity. This work was performed in collaboration with L. Weston, X. Y. Cui, A. Janotti, and C. Stampfl, and supported by DOE. [1] L. Weston, A. Janotti, X. Y. Cui, C. Stampfl, and C. G. Van de Walle, Phys. Rev. B 89, 184109 (2014). [2] L. Weston, A. Janotti, X. Y. Cui, C. Stampfl, and C. G. Van de Walle, Phys. Chem. Chem. Phys. 19, 11485 (2017).

Authors : Myung-Jin Lee, Seok Soo Lee, Victor Roev, Seungsik Hwang, Da-Hye Park, Seungsik Hwang, Seok-Gwang Doo, Yunil Hwang
Affiliations : Energy Material Lab, Samsung Advanced Institute Technology (SAIT), Samsung Electronics Co.

Resume : Solid Polymer Electrolytes (SPEs) offer a perfect solution to these safety concerns and to the enhancement of en-ergy density. However, polymer electrolytes developed so far are not good enough in terms of high-voltage stabil-ity, strength and flexibility, and therefore, there is a strong need for improvement in these aspects. To solve the described problems, a polymer electrolyte having a high oxidative decomposition potential and having improved high-voltage stability and sufficient ionic conductivity and mechanical properties is prepared. The polymer elec-trolytes composed of random grafted copolymers that include ion conductive unit and electrowithdrawing units with carbonate- or a fluorine-functional group show excellent high voltage stability and the mechanical strength. Herein, we have synthesized and developed the low Tg POEM-PDMS-X for Li metal batteries. Li metal battery using this SPEs show the improved cycling stability and Li metal efficiency as well as suppress the Li dendrites growth. The polymer electrolytes exhibited excellent comprehensive performance in terms of high ionic conduc-tivity (0.30 mS/cm with plasticizer at 60℃) and wide electrochemical window (4.4V)

Authors : Yaochun Liu, Yuanhua Lin
Affiliations : School of Materials Science and Engineering, Tsinghua University

Resume : Two-dimensional transition-metal dichalcogenides semiconductors (TMDCs) with layered structures are concerned as promising thermoelectric materials for several years. However, WSe2 as one of TMDCs is barely investigated. Herein, we systematically investigated the high-temperature electrical and thermal transport behaviors in layered structure WSe2, resulting in that WSe2 possesses high Seebeck coefficient and low thermal conductivity. The study of sintering process shows that the best electrical properties can be obtained in the sample sintered at 1123 K. Besides, anisotropic thermoelectric properties were also revealed. It is found that ZT in the direction parallel to the pressing direction is higher than that in the direction perpendicular to the pressing direction. The highest ZT value of 0.03 was obtained at 923 K, which is an appreciable value for pristine alloy material.

Authors : (1) Katja Fröhlich, (2) Isaac Abrahams, (3) Peter Blaha, (1) Atanaska Trifonova
Affiliations : (1) Electric Drive Technologies, AIT Austrian Institute of Technology GbmH, Giefinggasse 2, 1210 Vienna, Austria; (2) School of Biological and Chemical Sciences, Queen Mary University of London, E1 4NS London, UK; (3) Institute of Materials Chemistry, Vienna University of Technology, Getreidemarkt 9/165-TC,1060 Vienna, Austria

Resume : Symmetric lithium nickel manganese cobalt oxides (NMC) are of great interest as cathode materials for lithium-ion batteries, especially for automotive applications. However, a deeper understanding of the crystal structure changes during cycling is still needed in order to clarify aging phenomena and to improve its safety. Ab initio calculations provide information from which further details about materials’ structure and stability are obtained. The main advantage of this approach is that no experimental data is needed (except some knowledge or educated guess about the structure) and therefore, the optimization time is greatly reduced. As this cathode material is already commercialized, many simulations were performed already in the field. Caused by the symmetric mixture between the transition metals, which equally share (except some extend of cation mixing between lithium and nickel) 3a sites in the R-3m structure, the minimum size of calculated super cells contain three formula units. In this work, the number of atoms in the final model is very high (108 atoms in total) and the ordering of the transition metals is completely random. That way, one can clearly see the effect of neighbouring atoms and draw concrete conclusions about different stages of lithiation (or charge) and the effect on the local electronic structure. Different stages of charge of the cathode material were calculated, the structures optimized in terms of atomic positions and unit cell volume, and the results will be presented and compared to experimental data. Acknowledgement This work was financially supported by the Austrian Federal Ministry for Transport, Innnovation and Technology (bmvit) and the Austrian Research Promotion Agency (FFG).

10:30 Coffee break    
Authors : Yan YU
Affiliations : Department of Materials Science and Engineering, University of Science and Technology of China, 230026, Hefei, Anhui, P. R. China. & Max Planck Institute for Solid State Research, Heisenbergstr. 1, Stuttgart, 70569, Germany

Resume : Na-ion batteries (NIBs) have attracted rapidly increasing attention because sodium is abundant resources, low cost and their better safety. However, the development of NIBs is greatly hampered due to the lack of appropriate active materials for both cathodes and anodes, because of the large radius of Na+. NASICON-type Na3V2(PO4)3 (denoted as NVP) has recently been investigated as a promising cathode material for NIBs. While it is difficult to reach high rate performance of Na3V2(PO4)3 cathode due to the poor electronic conductivity of phosphates. For anode materials, NaTi2(PO4)3 has shown promising electrochemical performance. Here, we reported electrode materials for NIBs based on porous carbon with excellent rate performance: Carbon-coated nanosized Na3V2(PO4)3 embedded in the porous carbon matrix.[1] [2-5] The double carbon coating NVP could deliver high rate performance (44 mAhg-1 at 200C). This ultrahigh rate performance is comparable to that of supercapacitor, but with much higher energy density. We also designed NaTi2(PO4)3 particles embedded in micro-sized 3D graphene network to improve its electrochemical performance. The outstanding electrochemical performance of electrode materials with porous carbon network for NIBs is attributed to the special structure design, which confined a variety of advantages: hierarchical porous channels facilitating fast ions and electrons transport, carbon coated structure resulting in low resistances, good mechanical properties leading to the excellent morphology stability. References: [1] C. Zhu, P. Kopold, P.A. van Aken, J. Maier, Y. Yu*, Adv. Mater., (2016) DOI: 10.1002/adma.201505943. [2] X. Rui, W. Sun, C. Wu, Y. Yu*, Q. Yan*, Adv. Mater., 27 (2015) 6670-6676. [3] C. Wu, P. Kopold, Y.-L. Ding, P.A. van Aken, J. Maier, Y. Yu*, ACS Nano, 9 (2015) 6610-6618. [4] Y. Jiang, Z. Yang, W. Li, L. Zeng, F. Pan, M. Wang, X. Wei, G. Hu, L. Gu, Y. Yu*, Advanced Energy Materials, 5 (2015) 1402104. [5] C. Zhu, K. Song, P.A. van Aken, J. Maier, Y. Yu*, Nano Letters, 14 (2014) 2175-2180.

Authors : Lin Zhang
Affiliations : Leibniz University of Hannover; Leibniz Institute for Solid State and Materials Research Dresden

Resume : Silicon is an excellent choice for the lithium ion battery (LIB) anode owing to many of its excellent properties. To date, the practical implementation of Si anodes is hindered due to the enormous volume variation during lithiation/delithiation and the unstable solid electrolyte interphase (SEI) layers. Extensive efforts have been devoted to solving these problems. One typical approach is to use nanostructured silicon materials that can accommodate large volume change and maintain their structural integration over many cycles. Two-dimensional (2D) nanomembranes, on the other hand, are also quite promising due to their improved accessibility of Li+ and the small volume expansion inherited from the ultrathin structure. Moreover, when 2D nanomembranes naturally roll up into 3D tubular structures, their mechanical tolerance against stress as well as the loading density can be significantly enhanced. We demonstrated three types of Si based anodes in our recent works. A rolled-up SiOx/SiOy bilayer nanomembrane, where the functionalities of each layers can be engineered by the oxygen contens, shows an excellent capacity and structural integrity of several hundred cycles. To address the LIB safety issues, we investigated a Ti3+ self-doped TiO2/Ti bilayer nanomembrane based anode, which shows an ultra-long lifetime (for 6000 cycles at 10C, with an extraordinary retention of 100%) without any indication of catastrophic battery failure. Based on these works, a full battery with good cycling stability, excellent rate capability and high energy density is demonstrated based on the TiOx/Si/TiOx trilayer nanomembranes.

Authors : Chunfei Zhang, Sung Soo Kim, and Jong-Sung Yu*
Affiliations : Department of Energy Systems Engineering, DGIST, Daegu 42988, Republic of Korea

Resume : Graphite, as a traditional anode material, plays a prominent role in lithium ion batterie (LIB) commodity because of its high lithiation-dilithiation reversibility and low voltage window. Unfortunately, the capacity is limited to 372 mAh g-1. To search for materials with higher lithium storage capacity, a great number of investigations on metal oxides (or sulfides), Sn, P, and Si have been carried out in recent decades. Among these materials, silicon can make alloy with lithium in the form of Li22Si5 to deliver a highest theoretical gravimetric capacity of ~4200 mAh g-1, and thus is considered to be one of the most promising anode materials for next generation LIB. It is worth mentioning that its quite low delithiation potential and high lithium storage capacity can provide a high working voltage and energy density, which enable promising potential application in electric vehicles. However, those advantages are seriously offset by a great challenge of large volume expansion during lithiation process and the resultant breakage of bulk silicon particles and solid electrolyte interface (SEI), which causes a serious damage to the electrode structure and thus gives rise to a fast decay of the specific capacity. In this work, novel 3D spongy grapheme (SG)-functionalized silicon will be demonstrated by chemical vapor deposition for a LIB anode, which can overcome the common silicon issues in Si anode such as poor conductivity and volume expansion of Si as well as transfer of Li ion towards the Si. The elastic feature of graphene has excellent function to self-adaptively buffer the volume variation during charge-discharge process. In particular, different from traditional graphene or carbon shells (core-shell and yolk-shell), the spongy 3D graphene networks provide much improved unique functions with excellent long-cycle stability and rate capability. The Si@SG electrode exhibits excellent cycling performance with high reversible specific capacity (2330 mAh g−1 at 250 mA g-1 with an initial CE of 83.4%, and 1385 mAh g−1 at 500 mA g−1 after 510 cycles with a CE of 99.2%). A superior 95% capacity retention is achieved after 510 cycles. All the electrochemical performances get benefits from the well-designed functional SG shells, where interconnected nano-graphene structure not only guarantees a high conductive network but also provides more free paths for excellent mass transfer in addition to self-adaptive buffering capability.

Authors : Hyunah Kim, Jimin Park, Ki Tae Nam, Kisuk Kang
Affiliations : Hyunah Kim, Ki Tae Nam, Kisuk Kang; Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea. Jimin Park; Center for Biomaterials, Korea Institute of Science and Technology, 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul 136-791, Republic of Korea.

Resume : Splitting water into hydrogen and oxygen molecules via solar energy has been considered as one of the most environmentally-friendly ways to effectively utilize renewable energy resources from harvest to redistribution. Although it has been studied for more than a half century, oxygen evolution reaction (OER) are still regarded as a bottleneck in integrating overall water splitting system. The noble-metal catalysts such as Pt, IrOx, and RuOx showed outstanding OER catalytic activity, however the high costs remain as limitation. In this regard, the development of cost-effective, abundant-element based, and efficient OER catalyst is highly demanded. Inspired from the Mn4CaO5 cluster n nature, which shows remarkable catalytic performance in water oxidation, many researches focused on manganese-based water oxidation catalysts. We selected manganese-based K2MnP2O7 material as a model system to design efficient water splitting catalyst, and synthesized K2-xNaxMnP2O7 materials to compare the effect of redox inactive metal within K2MnP2O7 overall structure. Gradually shifted XRD pattern, the change of peak ratio, and tendency in refined lattice parameter implies that K2-xNaxMnP2O7 material was successfully synthesized. Interestingly, we observed that as the sodium ion replaces the potassium ion in K2-xNaxMnP2O7, the catalytic performance enhanced in the series of K2MnP2O7 < K1.8Na0.2MnP2O7 < K1.6Na0.4MnP2O7 < K1.4Na0.6MnP2O7. Moreover, K1.4Na0.6MnP2O7 showed high water oxidation catalytic ability compared with other previously reported Mn-based OER catalysts. We expect that our study provides valuable guidelines for developing an efficient oxygen evolution catalyst under neutral conditions.

Authors : Takeshi KOBAYASHI, and Yasutaka OHNO
Affiliations : Central Research Institute of Electric Power Industry (CRIEPI), 2-6-1, Nagasaka, Yokosuka, 240-0196, Japan

Resume : Central Research Institute of Electric Power Industry (CRIEPI), 2-6-1, Nagasaka, Yokosuka, 240-0196, Japan Element analysis and capacity estimation in both electrodes often have been conducted for clarifying a fading mechanism after disassembling the degraded commercial lithium batteries. However, the battery consists of many stacking anode sheets and cathode sheets in layers to increase battery capacity. These post-analyses are difficult to analyze all sheets of cathode and anode. We previously have studied electrochemical behavior of blended cathodes modeled for commercial lithium battery using in-situ X-ray diffraction (XRD) measurement [1]. In this study, we quantitatively estimated electrochemical behavior of both electrodes in 4 Ah-class battery without disassembling using in-situ XRD measurement at synchrotron facility [2]. We obtained XRD patterns of graphite anode and blended cathodes (LMO+NCA) during discharge process. These analysis result was found that the fading of LMO was greater than that of NCA. The calculated capacity of blended cathode and graphite were almost similar with actual capacity in the degraded battery. The result can be mainly explained by active lithium consumption on graphite. In this presentation, we will discuss that its capacity decrease can be satisfied theoretically the square root rule. Reference: [1] T. Kobayashi, et al., J. Mater. Chem. A, 2017, 5, 8653, [2] T. Kobayashi, et al., Lithium Battery Discussion (LiBD) abstract, 2017.

13:00 Lunch break    
Authors : L. Kavan, Z. Vlckova-Zivcova, H. Krysova, P. Cigler, V. Mortet
Affiliations : (LK, ZV, HK) J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-18223 Prague 8, Czech Republic; (PC) Institute of Organic Chemistry and Biochemistry, v.v.i. Academy of Sciences of the Czech Republic, Flemingovo nam. 2, 166 10 Prague 6, Czech Republic; (VM) Institute of Physics of the Czech Academy of Sciences, Prague, Czech Republic

Resume : Spectral sensitization of B-doped diamond (BDD) was carried out by anchoring of P1-dye (Dyenamo AB) with polyethyleneimine as a linker or by covalent anchoring. Alternative chemical modification of the diamond surface was performed through a combination of diazonium electrografting and Suzuki cross-coupling reactions. Dye-sensitized sensitized diamond exhibits cathodic photocurrents under visible light illumination in aqueous electrolyte solution with dimethylviologen serving as electron mediator. To enhance the roughness factor for light harvesting, nanotextured BDD was prepared via silica templating route either by spherical templates or electrospun nanofiber templates. Cathodic photocurrents under solar light illumination (AM 1.5) are about 3-times larger on nanostructured electrodes compared to those on flat diamond. Illumination of the sensitized electrodes with chopped light at 1 sun intensity causes an increase of the cathodic photocurrent density to ca. 15-22 μA/cm2. Photocurrent densities scale linearly with light intensity (between 0.1 a 1 sun), and they represent the largest values reported so far for dye-sensitized diamond electrodes. The photoelectrochemical activation of the sensitized diamond electrodes is accompanied with characteristic changes of the dark voltammogram of the MV2+/MV+ redox couple and with gradual changes of the IPCE spectra. BDD electrodes also show interesting electrocatalytic activity (approaching that of platinum) in the classical DSCs with sensitized titania and Co-based redox mediators. Acknowledgement: This work was supported by the Czech National Foundation, contract No. 13-31783S.

Authors : Anja Bieberle-Hütter, Rochan Sinha, Irem Tanyeli, Reinoud Lavrijsen, Richard van de Sanden
Affiliations : Anja Bieberle-Hütter (a)*, Rochan Sinha (a), Irem Tanyeli (a), Reinoud Lavrijsen (b), Richard van de Sanden (a, c) (a) DIFFER – Dutch Institute for Fundamental Energy Research, Department Solar Fuels, Eindhoven, the Netherlands (b) Physics of Nanostructures and center for NanoMaterials (cNM), Department of Applied Physics, Eindhoven University of Technology (TU/e), the Netherlands (c) Plasma and Materials Processing, Department of Applied Physics, Eindhoven University of Technology (TU/e), the Netherlands

Resume : Nanostructures originating from high ion flux, low energy He plasma exposure are known from fusion research as nanofuzz [1-3]. Nanofuzz is characterized by a large surface area and a high porosity (up to 90%) [2]. Such materials are desired in electrochemical and catalytic applications due to increased performance per projected area. In the field of water splitting, plasma nanostructured WO3 surfaces on bulk pellets showed five times higher performance compared to dense materials [4]. Recently, we showed that also thin films can be nanostructured by high ion flux plasma (~ 1023 m-2 s-1) even on brittle substrates [5]. The nanostructures are three dimensionally connected, stable during oxidation, and well adhering to the substrate. We show how the plasma exposure conditions impact the formation of the nanostructure [5]. Detailed electrochemical characterization resulted in an increased performance as well as different electrochemical mechanisms and structure-property relation [6]. In this presentation, we critically discuss these results [5,6] towards the viability of plasma nanostructuring for energy applications. [1] Baldwin et al., Nucl. Fusion 48 (2008) 035001. [2] Kajita et al., Appl. Phys. Express, 3 (2010) 085204. [3] De Temmerman et al., J. Vac. Sci. Technol. A 30 (2012) 041306. [4] De Respinis et al., ACS Appl. Mater. Interf. 5 (2013) 7621. [5] Bieberle-Hütter et al., Thin Solid Films 631 (2017) 50. [6] Sinha et al., to be submitted to Electrochim. Acta (2017).

Authors : Sara Drvaric Talian, Alen Vizintin, Klemen Pirnat, Iztok Arčon, Robert Dominko
Affiliations : Sara Drvaric Talian; Alen Vizintin; Klemen Pirnat; Robert Dominko; National institute of chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia Sara Drvaric Talian Faculty of Chemistry and Chemical Technology, Večna pot 113, 1000 Ljubljana, Slovenia Iztok Arčon University of Nova Gorica, Vipavska 13, 5000 Nova Gorica, Slovenia Iztok Arčon Institut Jožef Stefan, Jamova 39, 1000 Ljubljana, Slovenia

Resume : Solubility of sulfur and polysulfides depend on the several parameters where the selection of solvent(s) plays crucial role. Typical mechanism of Li-S batteries known from binary mixtures of solvents containing linear ethers (DME or TEGDME) mixed with dioxilane, can be divided into three regions, where the kinetics of high voltage plateau is a function of solubility of sulfur and its reduction to long chain polysulfides and low voltage plateau corresponds to the thermodynamic equilibrium of precipitation of Li2S from saturated solution of short chain polysulfides. Basically there are two equilibriums between solid-liquid and liquid-solid phases and additional equilibrium between liquid-liquid phases where a reduction of long chain polysulfides to short chain polysulfides occurs. The mechanism of sulfur reduction in the fluorine based ethers or even in carbonates is different due to limited or due to absence of polysulfides solubility. Nevertheless, polysulfides are present in both cases as determined by S k-edge X-ray absorption spectroscopy. But limited solubility influence the thermodynamic equilibrium of the high voltage plateau which is demonstrated as shorter high voltage signature in the galvanostatic curve positioned at lower voltage compared to voltage of sulfur reduction in the mixture of dioxilane and linear ethers. Differences between three case studies evaluated with UV-Vis spectroscopy and X-ray absorption spectroscopy will be discussed. References: [1] Dominko R, Ubrani MMP, Lapornik V, Vizintin A, Kozelj M, Novak TN, Arcon I, Stievano L, Aquilanti G; The journal of physical chemistry. C, (2015), 119, 19001-19010. [2] Ubrani MMP, Arcon I, Aquilanti G, Stievano L, Mali G, Dominko R; ChemPhysChem, (2014), 15, 894-904. [3] Drvarc-Talian S, Vizintin A, Pirnat K, Arčon I, Aquilanti G, Jeschke S, Johannson P, Dominko R, in preparation [4] Dominko R, et al., in preparation

15:30 Coffee break    
Authors : Charlotte Platzer-Björkman
Affiliations : Solid State Electronics, Engineering Sciences, Uppsala University, Box 534, 75121 Uppsala, Sweden

Resume : Thin film solar cells based on Cu2ZnSn(S,Se)4, “CZTS”, also called kesterite solar cells from the crystal structure, attract attention due to their all earth abundant constituent elements. Typical CZTS solar cells use the same device structure as Cu(In,Ga)Se2, “CIGS”, solar cells with molybdenum back contact and CdS/ZnO/ZnO:Al front contact stack. While the efficiency of CIGS solar cells has reached 22.6% for lab scale devices and 19.2% for submodules, the highest published efficiency for CZTS is only 12.6%. There are several possible reasons for this efficiency limitation. Secondary phase segregation is difficult to avoid and their influence on performance hard to assess since completely phase-pure devices are difficult to make. The energy band alignment at the heterojunction between CZTS and CdS is non-ideal for pure sulphide CZTS, but it is good for the lower band gap selenium rich CZTSSe. Back contact reactions giving interfacial Mo(S,Se)2 layers restrict the process window for CZTS annealing. Bulk CZTS contain a large density of defects and defect clusters. Even for stoichiometric CZTS, the density of some antisite defects is very high due to low formation energy, giving rise to an effective lowering of the electronic band gap. These different issues will be discussed in terms of their contribution to efficiency losses and potential solutions.

Authors : Jeha Kim, Vinaya Kumar Arepalli, and Younbae Shin
Affiliations : Department of Energy Convergence Engineering, Cheongju University

Resume : Tin sulfide (SnS) is chalcogenide semiconductor material promising for photovoltaic applications because of its high absorption coefficient ( >104 cm-1) and optimal band gap (1.1–1.4 eV). Even though CdTe, CIS, and CIGS based solar cells are commercially available in the market, they are suffering from scarcity of expensive Te, In and Ga and toxicity of Cd and Se. Hence SnS becomes an alternative absorber for next generation low cost thin film solar cells with non-toxic and earth abundant elements. Theoretically, maximum power conversion efficiency of SnS is more than 25% based on Shockley–Queasier limit. In this work, we report the influence of substrate temperature on the structural, optical and electrical properties of rf-sputtered SnS thin films grown on both Mo/SLG and Sn metal seed coated Mo/SLG. We also studied the effect of sulfurization on the rf-sputtered SnS thin films grown at various substrate temperatures. The synthesized SnS films were characterized by scanning electron microscopy, electron dispersive spectroscopy, X-ray diffraction, micro Raman spectroscopy, and UV-Visible spectroscopy. X-ray diffraction spectra confirmed that a dominant SnS pure phase of herzenbergite crystal structure existed with (101) and (111) as major orientation peaks. The solar cell was fabricated with a layer structure of SLG/Mo/SnS/CdS (or ZnOS)/i-ZnO/ITO/Al. We will discuss the properties of solar cells with different buffer layers such as CdS and ZnOS deposited by chemical bath deposition (CBD) and present the relationship between the structural characteristic of SnS absorber, buffer layers and the device performance SnS solar cells. Acknowledgement: This research was supported by the Technology Development Program to Solve Climate Changes of the National Research Foundation (NRF) funded by the Ministry of Science, ICT & Future Planning (NRF2016M1A2A2936759).

Authors : Grzegorz Matyszczak [1], Michal Wrzecionek [1], Krzysztof Wozniak [3], Damian Trzybinski [3], Cezariusz Jastrzebski [2], Sławomir Podsiadlo [1]
Affiliations : [1] Faculty of Chemistry, Warsaw University of Technology, ul. Noakowskiego 3, 00-664 Warsaw [2] Faculty of Physics, Warsaw University of Technology, ul. Koszykowa 75, 00-662 Warsaw [3] Chemistry Department, Warsaw University, ul. Ludwika Pasteura 1, 02-093 Warsaw

Resume : A large interest in semiconductors is observed due to their applications in electronics and renewable energy harvesting. Cu2ZnTiS4 and Cu2ZnTiSe4 are expected to show particularly appealing features which combined with their environmental harmlessness and low-cost production makes them promising materials for use in photovoltaics. Computational investigations show that these materials can have energy band gap approximately equal to that of kesterite Cu2ZnSnS4 while having about twice times higher absorption coefficient than Cu2ZnSnS4. In this study crystals of Cu2ZnTiS4 and Cu2ZnTiSe4 – prepared by the method of chemical vapour transport – have been investigated. The obtained materials have been characterized with X-ray diffraction, Raman scattering spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy.

Authors : Donia Fredj (1,2), Florent Pourcin (2), Riva Karsifi (2), Sadok Ben Dkhil (2), Christine Videlot-Ackermann (2) , Olivier Margeat (2) , Jörg Ackermann (2), Mohamed Boujelbene (1)
Affiliations : (1) Laboratoire Physico-Chimie de l’Etat Solide, LR11 ES51, Faculté des Sciences de Sfax, Université de Sfax, BP 3071 Sfax, Tunisie; (2) Aix-Marseille University, Centre Interdisciplinaire de Nanosciences de Marseille CINaM, UMR CNRS 7325, Marseille

Resume : Nowadays, organic-inorganic hybrid materials have been broadly investigated owing to their various properties used in optoelectronics and solar cell [1]. Here, we report synthesis of new organic-inorganic hybrid material which is obtained by slow evaporation at room temperature using the same organic cation for two different molar ratio. This compound is characterized by X-ray diffraction, infrared and Raman spectroscopy, optical absorption and photoluminescence measurements. We applied this new materiel as electron extraction layer in organic solar cells in regular device structure. Importantly, the energy band gap of these materials was found to be closed to that used in interfacial layers [2, 3, 4] of some organic solar cells. By optimizing optical, electrical, and morphological properties of these new wide bandgap materials, bulk heterojunction solar cells with conversion efficiency exceeding 9.7 % are obtained in normal device structures with all-solution-processed interlayers in normal device structure. More importantly, the morphology and especially the surface roughness of this hybrid layer is crucial to obtain hole blocking behavior leading to fill factor up to 72 %. [1] Vitalii Yu. Kotov et al., New J. Chem., 2016, 40, 10041--10047 [2] Sadok Ben Dkhil et al., Adv. Energy Mater. 2014, 4, 1400805 [3] S. Ben Dkhil et al., Adv. Energ. Mater. 2016, 1601486 [4] S. Ben Dkhil et al., Adv. Energ. Mater. (2016), 1600290/1-10.

Authors : Salvador Eslava
Affiliations : University of Bath, Department of Chemical Engineering

Resume : Facile, effective and greener approaches for the synthesis of nanostructured materials are key in the development of photocatalysts and photoelectrodes for artificial photosynthesis. Here I will present the recent developments we have achieved in my group in the preparation of nanostructured photocatalysts and photoelectrodes of TiO2, WO3, LaFeO3, and Fe2O3. We put emphasis not only on tuning their final morphology to maximize their surface area but also on finding greener approaches that will be more sustainable and easier to commercialize. For example, exploiting the amphiphilic properties of graphene oxide and its oxygen functional groups, we have successfully imparted two-dimensionality features to TiO2 and LaFeO3 photocatalysts and photoelectrodes, boosting their final performance. We have also successfully found greener approaches to anodize tungsten foil in the preparation of WO3 photoanodes, avoiding the frequent but dangerous use of HF. Finally, we have also found a greener and a more sustainable deep eutectic solvent for the microwave synthesis of hematite nanoparticles that can be doctor bladed for successful hematite photoanodes. In a nutshell, this presentation will cover the recent advances in my group in tailoring the nanostructure of photocatalysts and photoelectrodes for solar water splitting, together with the characterization that relates their properties to their activity.

Authors : Kai Zhang, Mihui Park, Jing Zhang, Yong-Mook Kang*
Affiliations : Department of Energy and Materials Engineering, Dongguk University-Seoul, Seoul 04620, Republic of Korea E-mail: (Y.-M. Kang)

Resume : Sodium-ion batteries (SIBs) are receiving increasing interesting today because they are viewed as ideal candidates that can at least partially substitute for Li-ion batteries. The cathode materials are important components of SIBs, but exploiting high-stable cathode materials is still a big challenge. P2-type layered compounds are promising cathodes owing to their high theoretical specific capacity, low diffusion barrier, and high ionic conductivity. However, P2-type layered compounds suffer from phase transformation from P2 to O2 during the first charge process. In this paper, we have presented a Zn-doped P2-type layered compound (Na0.83[Li0.25Mn0.7125Zn0.0375]O2) and its Na-storage properties. Compared with bare Na5/6[Li1/4Mn3/4]O2, the Zn-doped sample shows better cyclic stability and rate capability. The capacity in the 100th cycle at 0.2 C is higher for the Zn-doped sample (0.162 Ah g−1) than that for the bare Na5/6[Li1/4Mn3/4]O2 (0.139 Ah g−1). The capacities of the Zn-doped sample at 1, 2, and 5C still remain 0.138, 0.114, and 0.081 Ah g−1, respectively. The excellent performance of the Zn-doped sample is attributed to two aspects. One is that the Zn-doped sample avoids the phase transition during the first charge process to improve its structure stability. The other is that the Zn-doped sample has high electronic and ionic conductivities to effectively enhance the electronic transport and ionic diffusion. This paper provides an effective strategy to develop high-performance P2-type layered cathode materials for SIBs.

Authors : Syeda Wishal Bokhari 1, Ahmad Hassan Siddique 2, Pan Hui 1, Yao Li 2, Shenmin Zhu 1*
Affiliations : 1: State key Laboratory of Metal Matrix Complexes, School of Material Science and Engineering, Shanghai Jiao Tong University, China. 2: Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, China.

Resume : Graphene and carbon nanotube (CNTs) are widely studied as electrode materials for supercapacitors due to their cost effectiveness, high electrochemically active surface area (EASA) and high electronic conductivity. On the other hand, transition metal oxides (TMOx) especially iron oxides (FeOx) and iron oxide-hydroxides (FeOOH) offer good pseudocapacitive properties, which are beneficial to enhance the specific capacity of pseudocapacitors. Keeping in mind these properties, we have designed a simple graphene-CNT (GC) matrix in which CNTs freely stand on the graphene sheets, and decorated it with FeOOH nanorods (GC-F) in two steps by using a simple hydrothermal approach. When tested as a cathode for supercapacitor, it delivered a very high specific capacity of 350-600 F·g-1 at current densities of 1 A·g-1, 5 A·g-1 and 10 A·g-1 with a good cyclic retention of ca. 85% after 1500 cycles in 1 M LiNO3 electrolyte. This high performance is attributed to (i) uniform dispersion of FeOOH nanorods in the highly conductive GC matrix and (ii) high stability of the structure. The performance can further be enhanced by changing the mass ratio of GC matrix to FeOOH nanorods. This approach can be useful in designing the high-capacity electrode materials for supercapacitor applications.

Authors : Xiaolin Kang,1† Wenjing Huang,2 † Cheng Xu,1 Yanguang Li2* and Si Cheng1*
Affiliations : 1College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu, China. E-mail: 2Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, China,E-mail:

Resume : Unique two-dimension (2D) nanosheets possess great advantages over their bulk counterparts owing to their high surface area-to-volume ratio and high-density unsaturated atoms exposed on the surface, so as to exhibit substantially distinctive physical and chemical properties, especially in many catalytic regions.1 Pd-based monometallic or multimetalic nanosheets have drawn specially increasing attention as the excellent catalysts for direct ethanol fuel cells (DEFCs) in alkaline.2 Herein, a synthesis strategy for the fabrication of two-dimension PdAg dendritic nanosheets is reported. PdAg nanosheets with snow-like dendrites were prepared by co-reduction of the metal precursors in the present of special surfactant. The effects of carbochain length of surfactant on the morphological evolution from 3D to 2D were investigated in detail. The prepared PdAg dendritic nanosheets showed superior catalysis of ethanol electrooxidation due to their specific dendritic structure.

Authors : Vinoth Ganesan, Jinkwon Kim
Affiliations : Kongju National University; Kongju National University

Resume : Hollow nanostructures with tailored shell architectures are attractive for electrochemical energy storage applications. Herein, we synthesized template engaged CoSe2 nanoboxes (NBs) by utilization of Co-Prussian blue analogue (PBA). The synthesis realize through reaction between the pre-synthesized Co-PBA NBs and Se powder at elevated temperature. Electron microscopy studies reveals that the CoSe2 nanoboxes has hollow void with average sizes of 400 nm and BET studies implying that nanoboxes has exhibit large surface area. Benefiting from the desirable structural features and compositional merits, these well-defined CoSe2 nanoboxes has exhibits the OER performance over the precious IrO2 catalyst. The as-synthesized CoSe2 NBs delivered overpotential of 335 mV, higher current density of 94 mA cm-2 and lowest Tafel slop value of 54.2 mV dec-1. In addition the nanoboxes showed exhibit durability for 4 h, suggesting potential candidate for alkaline fuel cells.

Authors : Yao Zhang, Yanfang Gao* and Jinrong Liu
Affiliations : School of Chemical Engineering, Inner Mongolia University of Technology, No. 49 Aimin Street, Xincheng District, Hohhot 010051, P. R.

Resume : Supercapacitors (SCs) have fascinated great interest in addressing the environmental pollution and energy crisis by virtue of providing a higher power density immediately with shorter charging time simultaneously, and longer cycle lifetime continually than batteries. Herein, Ni3+ doped NiLa layered double hydroxide (NiLa-LDH) nanosheets with a thickness of about 1~2 nm have been synthesized and applied to pseudocapacitors. The Ni3+ doped NiLa-LDH exhibits excellent electrochemical performance, including a high specific pseudocapacitance (2250 F g−1 at 1 A g−1) and long durability compared with undoped NiLa-LDH mainly due to the increased electronic conductivity of the increased Ni3+ species. Therefore, this work is expected to take a significant step towards exploring a novel nanosheet electrode materials with unique physicalchemistry properties for applications in energy storage and conversion.

Authors : Yu-Kuei Hsu, Zhi-Qian Hsiao
Affiliations : Department of Opto-Electronic Engineering, National Dong Hwa University

Resume : The photoelectrochemical (PEC) characteristics of cuprous oxide (Cu2O) thin films with different dopant of alkali ions, such as Li+, Na+, and K+, are investigated for hydrogen generation from water splitting. The electrodeposition technology is employed for growing the Cu2O thin films from a pH-adjusted electrolyte consisting of LiOH, NaOH or KOH. The unintentional doping of alkali ion into Cu2O thin films is the significant effect on the resulted morphology, crystalline orientation and optical properties during the electrodeposition process. From XRD patterns, the changing relative intensity of (111) and (200) peaks in Cu2O thin films with different alkali ions can be concluded to various degree of substitution by alkali ions. In addition, the effect of various alkali ion dopants on the vacancy related photoluminescence was also examined. Based on this peculiar nature, therefore, the alkali ion-dependent PEC activities of Cu2O thin films are further systematically analyzed by Mott-Schottky analysis, three-electrode linear sweep voltammetry, and incident photo-to-electron conversion efficiency. Most interestingly, the Cu2O thin film with Li+ dopant displays the higher photoactive response than the other samples, which may be ascribed to the large portion of (111) orientation and less structural vacancy. According to our investigation, the understandings of morphology effect on PEC activity give the blueprint for materials design in the application of solar hydrogen.

Authors : Algita Stankevičiūtė1, Fariza Kalyk1, Gintarė Budrytė1, Brigita Abakevičienė1,2
Affiliations : 1 Department of Physics, Kaunas University of Technology, Studentu str. 50, LT-51368 Kaunas, Lithuania 2 Institute of Materials Science, Kaunas University of Technology, K. Barsausko srt. 59, LT-51423 Kaunas, Lithuania

Resume : Samaria-doped ceria has widely used in various solid oxide fuel cells (SOFCs) as electrolyte, fossil fuel technology, for gas sensing devices and in automobile exhaust systems. In this work, samaria-doped ceria (Ce0.8Sm0.2O1.9, SDC) powders, prepared by a glycine nitrate combustion method, were developed for intermediate-temperature solid oxide fuel cells (IT-SOFCs). Despite the large variety of methods to synthesize SDC powders, including Pechini, sol-gel, co-precipitation techniques, glycine combustion method attracts a lot of attention due to low cost and simplicity of the technique. The thermal decomposition of the synthesized powders was investigated by the thermogravimetric (TG) and differential thermal (DTA) analysis. The microstructural and morphological properties of nano-sized samaria-doped ceria were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) techniques, and Brunauer-Emmet-Teller (BET) surface analysis. The thermal analyses together with XRD results demonstrate the effectiveness of the glycine combustion process for the synthesis of pure phase nanocrystalline powders. The AC conductivity of sintered pellets was observed by two-probe impedance spectroscopy in the temperature range 200-600 C, and from 1 Hz to 3 MHz frequencies. The platinum paste was used onto either side of the sintered SDC pellets to serve as an electrode.

Authors : F. Bouhjar , B.Marí and B. Bessaïs
Affiliations : a. Institut de Disseny i Fabricació, Universitat Politècnica de València. Camí de Vera s/n 46022 València (Spain) b. Laboratoire Photovoltaïques, Centre de Recherches et des Technologies de l?Energie Technopole H.lif 2050(Tunisia) c. University of Tunis

Resume : p-CuSCN/n-Fe2O3 heterojunctions were electrochemically prepared by sequentially depositing ?-Fe2O3 and CuSCN films on FTO substrates. ?-Fe2O3 and CuSCN films and ?-Fe2O3/CuSCN heterojunctions were characterized by Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-ray spectroscopy (EDX), and X-Ray Diffraction (XRD) measurements. Pure crystalline CuSCN films were electrochemically deposited on ?-Fe2O3 films by fixing the SCN/Cu molar ratio in the electrolytic bath to 1:1.5 at 60 °C and a potential of -0.4 V. The photocurrent measurements showed an increase of the intrinsic surface states or defects at the ?-Fe2O3/CuSCN interface. The photoelectrochemical performance of the ?-Fe2O3/CuSCN heterojunction was examined by chronoamperometry and linear sweep voltammetry techniques. It was found that the ?-Fe2O3/CuSCN structure exhibits a higher photoelectrochemical activity when compared to ?-Fe2O3 thin films. The highest photocurrent density was obtained for ?-Fe2O3/CuSCN films in 1 M NaOH electrolyte. This high photoactivity was attributed to the high active surface area and to the external applied bias favoring the transfer and separation of photogenerated charge carriers in ?-Fe2O3/CuSCN heterojunction devices. The flat band potential and the donor density were found to be maximal for heterojunction sample. These results suggest a substantial potential for applying heterojunction thin films in photoelectrochemical water splitting applications.

Authors : Bebi Patil a, Suhyun Ahn b, Seongil Yu b, Hyeonjun Song c, Youngjin Jeong c, Heejoon Ahn
Affiliations : a Institute of Nano Science and Technology, Hanyang University, Seoul 04763, South Korea b Department of Organic and Nano Engineering, Hanyang University, Seoul 04763, South Korea c Department of Organic Materials and Fiber Engineering, Soongsil University, Seoul 07027, South Korea

Resume : The coaxial fiber-shaped asymmetric supercapacitor (CFASC) is a promising energy storage device in wearable and portable electronics, because of its high flexibility, small size, and light weight. However, the energy density of most of the fiber shaped supercapacitors is limited due to their limited potential range. Herein, we successfully developed a CFASC made up from MnO2/CNT-web paper as a cathode coupled with Fe2O3/carbon fiber as an anode with high operating voltage (2.2 V). The prepared CFASC device shows a high volumetric energy density of about 0.449 mWh cm-3 at 0.022 W cm-3 power density, which is appreciably higher than most reported fiber type supercapacitors. Additionally, CFASC exhibits good rate capability, long cycle life, and high volumetric capacitance (0.67 F cm-3) with excellent flexibility. The promising performance of CFASC illustrates its potential for portable and wearable energy storage.

Authors : Samantha Husmann, Aldo J. G. Zarbin
Affiliations : Chemistry department, Federal University of Paraná (UFPR), CP 19081, CEP 81531-990, Curitiba, PR, Brazil

Resume : Hexacyanometallates (HCMs) have a face centered cubic structure with a generic formula AM[M?(CN)6] where M and M? are metals coordinated to nitrogen and carbon, respectively, and A is a cation. Their porous structure allows cation intercalation during metals redox processes, which makes them suitable for battery applications. The performance of these materials is directly related to lattice size, stoichiometry, defects and stability, which depends on the metal species and synthetic conditions. Our group developed a route to prepare composites between HCMs and carbon nanotubes (CNTs) filled with metallic species, where these species act as source of metal ions necessary to HCMs formation.1 In this work, the effect of the cation used during HCMs synthesis and electrodeposition over CNTs thin films were evaluated in terms of structure and performance as aqueous battery cathode. Thin films of CNTs filled with iron (NFe) or cobalt (NCo) species were prepared trough liquid/liquid interfacial method developed in the group.2 The films were then modified by cyclic voltammetry in aqueous solutions containing the precursor hexcyano-salt and one of the three different electrolytes: KCl, NaCl or LiCl (0.1 mol L-1). Three different HCMs in the three electrolytes were prepared, namely Prussian blue (AxFe[Fe(CN)6]), ruthenium purple (AxFe[Ru(CN)6]) and cobalt hexacyanoferrate (AxCo[Fe(CN)6]). Through several characterizations, it was observed that the cation not only affects HCM structure but also interaction with the CNTs and thus, composite stability. The films were applied as K+, Na+ and Li+ aqueous battery cathodes. Capacity, rate retention and offset as well as charge/discharge stability were evaluated.

Authors : Atsushi Nitta1, Yuki Imamura2, Kazuya Kawahara2, Yuki Urushima1, Kazuhiro Takeda3
Affiliations : 1 Department of Electronic Control Engineering, National Institute of Technology, kagoshima College, Kirishima, Japan; 2 Advanced Mechanical and Electronic Systems Engineering, National Institute of Technology, kagoshima College, Kirishima, Japan; 3 Department of Information Engineering, National Institute of Technology, kagoshima College, Kirishima, Japan

Resume : Flexible devices manufactured using simple processes, such as printed electronics using printing methods and coating methods, have recently attracted the attention of many researchers. In particular, organic thin-film solar cells, organic electroluminescence displays, and organic transistors using organic materials have been actively studied. In these electronic devices, transparent electrodes, which transmit visible light and possess conductivity, are essential components. An indium tin oxide (ITO) thin film has been most commonly used as a material for a transparent conductive film. However, an ITO thin film is not suitable for flexible devices because they need flexibility and elasticity, but the thin film shows fragility to bending stress and is produced using high-temperature vacuum treatment. To solve this problem, we focused on the production of an organic transparent conductive film using an inkjet printer. However, to use printing technologies for the production of an organic transparent conductive film, the material must be prepared in the form of ink, the prepared ink must be optimized, the surface of the film must be uniform during printing, and the performance of the film must be improved; otherwise the film cannot be practically used. We have focused on poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS), an organic electroconductive material exhibiting high flexibility and conductivity, as a substitute for ITO. We have produced an organic transparent conductive film on a polyethylene naphthalate film substrate using an inkjet printer. To homogenize the surface state of a PEDOT/PSS thin film and to stably produce the thin film, the present study examined annealing and a solvent for ink. When annealing was performed between printing operations, the aggregation of PEDOT/PSS particles was inhibited and the surface state of the thin film was homogenized. By this, the interface state of each layer was improved, thereby improving the electrical characteristics of the thin film. In our previous studies, ethanol was effective as a solvent to decrease the viscosity of ink. However, ethanol facilitated the coagulation of ink and the aggregation of the produced PEDOT/PSS thin film. To produce a stable thin film, we used dimethyl sulfoxide (DMSO), a high-boiling point and low-viscosity solvent, as a substitute for ethanol. Since viscosity was higher in DMSO-containing ink than in ethanol-containing ink, the homogeneity of the thin film was higher when ethanol-containing ink was used than when DMSO-containing ink was used. However, because the electrical characteristics were improved due to the improvement in the conductivity and the printer did not get clogged with coagulated ink, a high-quality transparent conductive film could be stably produced. These results will be useful for the practical application of flexible devices manufactured using only inkjet printing.

Authors : Dae Sik Kim*, Goojin Jeong**, Hansu Kim*
Affiliations : *Department of Energy Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 133-791, Republic of Korea **Advanced Batteries Research Center, Korea Electronics Technology Institute, 68 Yatap-dong, Bundang-gu, Seongnam 463-816, Republic of Korea

Resume : Along with the rapid growth in robots, mobile electronics and electric vehicles (EVs) technology, lithium ion batteries (LIBs) are facing several technical challenges such as higher energy density and fast charging capability. Graphite, currently used anode materials for LIBs, has technical limitations to be used for robots, mobile electronics and EVs in terms of energy density and fast charging capability. To solve these problems, various anode materials have been suggested for alternative graphite anode material. In this work, titanium dioxide coated graphite was investigated as an anode material with fast charging capability for LIBs. The proposed core-shell structure, titanium dioxide coated graphite anode electrode exhibited an excellent rate capability of 96.4 % of the capacity retention at a rate of 10 C compare to that tested at a rate of 0.2 C without any degradation of reversible capacity and long-term cycle performance. The characterization, microstructure and electrochemical properties of the titanium dioxide coated graphite will be discussed in more detail.

Authors : Ji Young Ju, Seulgi Ji, Jin Kyu Kim, Seul Ki Choi, Sanjith Unithrattil,# Sun Sook Lee, Ha-kyun Jung, Yongku Kang, Yongseon Kim,* Won Bin Im,# Sungho Choi
Affiliations : Advanced Battery Materials Research Group, Korea Research Institute of Chemical Technology, 141 Gajeongro, Yuseong, Dajeon, Republic of Korea; #School of Materials Science and Engineering and Optoelectronics Convergence Research Center, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757, Republic of Korea;*Department of Materials Science and Engineering, Inha University, 100 Inharo, Nam-gu, Incheon, Republic of Korea.

Resume : Morphology and crystal phase evolution-preserved MnO2- or Mn3O4-anchored reduced graphene oxide (rGO) composites are easily obtained and their electrochemical properties behavior is investigated. Within the controlled annealing conditions, the MnO2/GO mixture is thoroughly converted to the phase-pure MnO2/rGO and Mn3O4/rGO composite electrode materials. We visualize the abrupt capacity change in the initial stages, which normally occurs in a nanopaticle-supported composite electrode, via comparative analysis between the electrochemical impeadance spectrscopy and the phase stability in a DFT calculation. Semispherical Mn3O4 anchored-rGO composite electrode material creates more stable anode capacity retention under the repetitive electrochemical reactions and activates the Li+ ⇄ LiOx(s) conversion reaction at Li-air cathode owing to the electrochemically favorable complex structure with an effective large contact area between active materials and the conducting medium.

Authors : Guillermo A. Ferrero, Marta Sevilla, Antonio B. Fuertes
Affiliations : Instituto Nacional del Carbón (CSIC), P.O. Box 73, Oviedo 33080, Spain

Resume : A simple template-free and cost-effective synthesis approach towards mesoporous carbons is herein presented. The procedure is based on the straightforward carbonization of non-alkali organic salts such as citrate salts of iron, zinc or calcium. The in-situ formed Fe, ZnO and CaO nanoparticles act as templates, giving rise upon their removal to carbon materials with a large specific surface area of up to ~1600 m2 g-1 and a porosity made up almost exclusively of mesopores. Furthermore, an additional heat-treatment step in the presence of melamine allows the synthesis of nitrogen-doped carbons with a high nitrogen content (~ 8-9 wt %) without compromising the textural properties. The developed mesoporous carbon materials were tested as electrodes for supercapacitors and as electrocatalysts for the oxygen reduction reaction (ORR) in fuel cells. As electrodes, the carbon materials were analyzed in aqueous (1 M H2SO4) and ionic liquid electrolytes (EMImTFSI/AN). They exhibit high specific capacitances of 200-240 F g-1 in 1 M H2SO4 and 100-130 F g-1 in EMImTFSI/AN, and an excellent rate capability in both electrolytes. When used as electrocatalysts for the ORR, the metal-free N-doped carbon materials predominantly catalyze the 4 e- process, with an onset potential of 0.9 V (vs. RHE) and a superior kinetic current density to that of Pt/C under basic conditions. In addition, the developed catalysts show a higher stability than commercial Pt/C and excellent electrocatalytic selectivity against methanol crossover.

Authors : Marta Sevilla, Guillermo A. Ferrero and Antonio B. Fuertes
Affiliations : Instituto Nacional del Carbón (CSIC), P.O. Box 73, Oviedo 33080, Spain

Resume : A simple and environmentally-friendly synthesis approach for the production of stable and easily processable dispersions of graphene in water is here presented. The process, based on an electrochemically assisted process, includes three steps: a) electrochemical exfoliation of graphite in (NH4)2SO4, b) sonication to separate the oxidized graphene sheets and c) reduction of the oxidized graphene to graphene. This strategy represents an alternative to the classical chemical exfoliation methods (v.g. Hummers´ method), which are more complex, harmful, time-consuming and dangerous. The procedure involves relatively short processing times and allows high yields. Around 30 wt.% of the initial graphite is converted to graphene, which forms stable and well-dispersed aqueous dispersions with a concentration of around 2-3 mg/mL. The graphene sheets have a C/O atomic ratio of 11.7, a lateral size of  0.5-1 µm and they contain only a few graphene layers, most of which are bilayer sheets. The processability of the aqueous dispersions of graphene allows them to be used directly for fabricating a variety of macroscopic graphene structures. As proo0f of concept, graphene aerogels with a high absorbent capacity and graphene films for use as electrodes in supercapacitors were easily prepared from these graphene dispersions.

Authors : Faheem Butt, Mike Dao, Armin Lang, Wolfgang Kreuzpaintner, Aliaksandr S. Bandarenka
Affiliations : 1Physik-Department, ECS,Technische Universität München, James-Franck-Str. 1, D-85748 Garching, Germany 2Physics Department, Chair for neutron scattering, Technische Universität München, James-Franck-Straße 1,D-85748 Garching, Germany 3Nanosystems Initiative Munich (NIM), Schellingstraße 4, 80799 Munich, Germany

Resume : Graphitic carbon nitride (g-C3N4) has emerged as an optimal material for photocatalysis, electronic assemblies, energy storage and conversion applications. To realize the practical use of g-C3N4 material large scale production is highly desirable. Microwave-assisted schemes can overcome these challenges and provide robust, low-cost and scalable approaches to synthesize various materials in the micro and nanoscale regime. This method provides a degree of freedom to tune C to N ratio by just varying the microwave reaction time. In this work we designed an innovative method to tailor melamine in microwave reactor by pre-treatment with nitric acid (HNO3) to obtain porous g-C3N4 nanostructures using recrystallization process of melamine. The electrochemical properties of the g-C3N4 were studied by performing electrochemical measurements in different alkali metal cations electrolytes. The g-C3N4 porous nanostructures show a reasonable specific capacitance in different electrolytes such as KOH, NaOH and LiOH respectively. These studies elucidates the electrochemical behavior of g-C3N4 as supercapacitor material.

Authors : Shuangqiang Chen, Laifa Shen, Peter A. van Aken, Joachim Maier, and Yan Yu*
Affiliations : 1 Max Planck Institute for Solid State Research. Heisenbergstrasse 1, 70569 Stuttgart, Germany. 2 Key Laboratory of Materials for Energy Conversion Chinese Academy of Sciences Department of Materials Science and Engineering, University of Science and Technology of China Hefei, Anhui 230026, China

Resume : To address the challenge of huge volume change and unstable solid electrolyte interface (SEI) of silicon in cycles,[1-4] causing severe pulverization, this paper proposes a ?double-shell? concept. This concept is designed to perform dual functions on encapsulating volume change of silicon and stabilizing SEI layer in cycles using double carbon shells. Double carbon shells coated Si nanoparticles (DCS-Si) are prepared. Inner carbon shell provides finite inner voids to allow large volume changes of Si nanoparticles inside of inner carbon shell, while static outer shell facilitates the formation of stable SEI. Most importantly, inter-shell spaces are preserved to buffer volume changes and alleviate mechanical stress from inner carbon shell. DCS-Si electrodes display a high rechargeable specific capacity of 1802 mAh g?1 at a current rate of 0.2 C, superior rate capability and good cycling performance up to 1000 cycles. A full cell of DCS-Si//LiNi0.45Co0.1Mn1.45O4 exhibits an average discharge voltage of 4.2 V, a high energy density of 473.6 Wh kg?1, and good cycling performance. Such double-shell concept can be applied to synthesize other electrode materials with large volume changes in cycles by simultaneously enhancing electronic conductivity and controlling SEI growth. The double-shell concept may be applied to modify other electrode materials as challenges of buffering volume change, enhancing electric conductivity and controlling the growth of SEI are commonly faced in lithium ion batteries and sodium ion batteries.

Authors : Pascale Chenevier,1 Gérard Lapertot,2 David Aradilla,1 Peter Reiss,1 Laurent Puech,3 Olga Burchak3
Affiliations : 1 Univ. Grenoble Alpes, CEA, CNRS, INAC, SyMMES, F-38000 Grenoble, France ; 2 Univ. Grenoble Alpes, CEA, INAC, PHELIQS, F-38000 Grenoble, France ; 3 EnWireS SAS, F-38000 Grenoble, France

Resume : First produced by thin film technologies (CVD growth or etching), silicon nanowires (SiNWs) have shown great promises in nanoelectronics, sensors and energy storage. For the latter, high quantities of SiNWs are required. We recently developed a new technology of SiNW synthesis that allows for the preparation of large quantities of SiNWs in bulk in a small, simple reactor within a few hours. Our SiNWs are grown on metal nanoparticles deposited on an unreactive nanopowder of NaCl. After synthesis, the NaCl powder is dissolved in water to recover a dense mat of pure SiNWs. From an air-stable organosilane oil as Si source, about 200mg of SiNWs are obtained in a 100mL steel reactor. NaCl particles play a critical role as a ?solid solvent?, keeping catalysts available to reactive gases and apart from each other during growth. Bulk grown SiNWs behave differently from SiH4-fed CVD-grown SiNWs: long and very thin (10nm), very small in diameter, they are strongly hydrophobic and show a low oxygen content even after exposure to air. Lithium-metal batteries made of SiNW-based anodes had a long cycling ability with a stable, high energy capacity (1800mAh/gSi over >100 cycles at 1C) with an initial capacity loss in the first charge-discharge cycles as low as 20%.

Authors : Nuria Vicente, Germà Garcia-Belmonte
Affiliations : Institute of Advanced Materials (INAM), Universitat Jaume I, 12006 Castelló, Spain

Resume : Ions diffuse through the hybrid halide perovskite lattice allowing for a variety of electrochemical applications as perovskite-based electrodes for batteries. It is still unknown how extrinsic defects as lithium-ions interact with the hybrid perovskite structure during the diffusion and charging process. It is shown here that Li+ intake/release proceeds by topotactic insertion into the hybrid perovskite host. Therefore, CH3NH3PbBr3 is reported to be a promising anode material. Ion intercalation into the host electrode without severe distortion of the CH3NH3PbBr3 lattice explains the reversible Li+ storage. It is also reported here that the electronic structure remains basically unaltered for the potential window of interest. Long-term specific gravimetric capacity attains significant values approaching 200 mA h g-1. In terms of molar content, lithiation reaches values as high as x=3 (moles of lithium per mole of methylammonium), an outstanding value in comparison to other intercalation compounds. CH3NH3PbBr3 exhibits three main properties: (i) it allows for high insertion concentrations with x>>1, and simultaneously (ii) it exhibits small structural distortions (topotactic intercalation). Importantly, (iii) the rate capability does not exhibit significant reduction for charging currents between 1 C and 0.25 C, indicating the potentiality of perovskite-based materials for high power battery applications. Since determination of defect diffusivities in perovskite films is inherently complex, it is proposed here an approach that takes advantage of the intercalation and migration of extrinsic lithium ions into methylammonium lead bromide perovskite to unambiguously extract diffusivity values. To this end, Li-ion diffusion is addressed by means of electrochemical impedance spectroscopy which reveals the fast ionic conduction character of the hybrid perovskites. Our findings indicate the outstanding electronic and ionic properties of lead halide perovskites, and their potential use as energy storage materials.

Authors : V.V. Volkov, E.V. Makhonina, A.E. Medvedeva, L.S. Maslennikova, Yu. A. Politov, and I.L. Eremenko
Affiliations : Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky Ave. 31, Moscow, 119991, Russia

Resume : Lithium-ion batteries are currently used in many portable electronic devices. However, their practical use in high energy storage devices for electric and hybrid vehicles requires much better performance such as higher energy density, good safety operation and longer lifetime. Apparently, the enhanced cathode stability and extended lifetime during the battery cycling should play a vital role for improved Li-ion battery performance. In present work we demonstrate that better battery performance can be achieved by the coating of Li-ion cathode with thin epitaxial a-Al2O3 oxide film making a better cathode protection at battery cycling. The initial NMC-cathode of composition LiNi0.40Mn0.40Co0.20O2 [1] was coated by the surface chemical treatment making a mixed alumina and carbon film on the cathode material. The presence of the alumina and carbon was proven by the ICP-AES analysis, XPS, SEM EDS microanalysis and the electron diffraction (ED). A local ED analysis performed for cathode grains revealed an epitaxial growth of thin a-Al2O3 corundum film directly on basal {001} facets of NMC grains. Notice that side-view {010}-facets of such grains remained free from a-Al2O3 film, thus leaving enough room for Li-ion diffusion into cathode structure. This result helps to explain a cycling performance and rate capability improvement of the alumina-coated cathodes versus uncoated NMC samples in terms of better surface stability for cathode grains protected by stable a-Al2O3 corundum film. This work was supported by the Russian Science Foundation Grant # 17-13-01424 (2017). Ref.: [1] E.V. Makhonina, A.E. Medvedeva, V.S. Dubasova, V.V. Volkov, Yu. A. Politov, I.L. Eremenko, International Journal of Hydrogen Energy 41(2016) 9901- 9907.

Authors : Huong LE, Thanh-Tuan BUI, Nawee KUNGWAN, Fabrice GOUBARD.
Affiliations : Laboratoire de Physicochimie des Polymères et des Interfaces, Université de Cergy-Pontoise, France ; Department of Chemistry, Chiang Mai University, Thailand.

Resume : Over the past five years, a rapid progress in organometal halide perovskite solar cells (PSCs) has greatly influenced emerging solar energy science and technology. In PSCs, both the overlying hole transporter material (HTM) and a controlled interfacing layers are critical for achieving high power conversion efficiencies (PCEs) and for protecting the air-sensitive perovskite active layer. As the new candidate, acridone-based molecules were designed and synthesized from ready commercial precursor 9(10H)-acridone by simply synthetic procedures. By incorporating in 2,7-positions of acridone-core with various strong electron rich groups such as 4,4?-dimethoxy-diphenylamine, 4,4?-dimethoxy-triphenylamine or phenothiazine, these molecules were evaluated on photophysical, electrochemical and thermal properties. Because of donor-acceptor structure, these molecules provided intermolecular charge transfer and/or intramolecular charge transfer to each other. Modification electron-donating group lead to tunable HOMO level and keep maintained LUMO level, their energy level could be compatible adapted with conductance band of the TiO2 layer and the valence band of perovskite layer. The presence of methoxy group (-OCH3) or phenothiazine-sulfur rich, they would be supported to charge carriers, increased hole mobility and conductivity. A combination of experimental and computational methods, they supported to optimize the device fabrication in progress. We strong believe that these novel perovskite-based materials will be the promising candidate for photovoltaic solar cells and further in organic electronic devices.

Authors : A. Boileau (1), A. Cheik (2), M. Boisserie (2), P. Marie (2), A. Fouchet (1), A. David (1), C. Frilay (2), C. Labbé (2), F. Gourbilleau (2), U. Lüders (1)
Affiliations : (1) Normandie Univ, ENSICAEN, UNICAEN, CNRS, CRISMAT, 14000 Caen, France; (2) Normandie Univ, ENSICAEN, UNICAEN, CEA, CNRS, CIMAP, 14000 Caen, France

Resume : In recent years, SrVO3 vanadate was shown to be a good transparent conductor in its crystalline phase. This material seems to be a serious alternative material as a substitute for indium tin oxide (ITO) which suffers from poor mechanical properties and price fluctuations. However, the high temperature necessary for the epitaxial growth of SrVO3 is a serious hurdle for its integration into different technologies. Therefore, the growth and the properties of films deposited at low temperatures have to be investigated and optimised. In this work, SrVO3 thin films have been deposited by Pulsed Laser Deposition onto SrTiO3 (100) oriented substrates for growth temperatures between 300°C and 700°C. Structural characterisation by X-ray Diffraction, as well as electrical (Van der Pauw) and optical characterisations (FTIR, Near IR-Visible and ellipsometry spectroscopies) have been systematically carried out. SrVO3 thin films deposited at low temperature exhibit an outstanding structural quality. Electrical measurements have shown a wide enhancement of the transport properties when the growth temperature is decreased. NIR-Visible spectroscopy showed that the plasma frequency is limited to the lower visible range whereas SrVO3 films exhibit a good transparency in the optical window (400-800 nm). Ellipsometry analyses were used to retrieve the optical parameters from the layers on the basis of correlated metals. Finally, the ellipsometry data were used to simulate the optical properties and were successfully compared to the NIR-Visible spectra. These optical and electrical investigations confirm that SrVO3 deposited at low temperature can be a promising material for transparent conductive layers.

Authors : R.А. Shkarban, S.I. Sidorenko, Yu.N. Makogon
Affiliations : National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute», 03056, Prospect Peremogy 37, Kyiv, Ukraine, е-mail:

Resume : The solution to energy security by improving the efficiency of alternative energy generation, the search for new, clean and renewable energy sources is a key objective of both science and the economy. One of the ways to increase the efficiency of thermoelectric coefficient (ZT) – use skutterudite CoSb3, which corresponds to the concept G. Slack "phonon glass – electron crystal". In addition, the transition from bulk materials to the nanoscale allows to further increase ZT due to increased defects in the structure. It is determined that at depositing films (30 nm) on the substrate at the room temperature is formed on amorphous state. Upon further heating, after crystallization the region of CoSb3 phase existence is extended (75-80) atm.% Sb in comparison with the massive state (75 at.% Sb). By increasing the substrate temperature up to 200oC is formed crystalline state and the laws of the phase composition formation in the Co-Sb films are characterized by a sequence that is similar to the diagram of phase equilibrium for a massive state of Co-Sb system. It is established that CoSb3 films are thermally stable up to ~300°C. The annealings of Co-Sb films both in vacuum and in nitrogen atmosphere, at temperatures higher 300°C lead to a sublimation as to over free antimony and antimony with CoSb3 crystal phase. It is shown that the influence of the annealing atmosphere in Co-Sb films displayed more intense sublimation of the antimony at the annealing in vacuum. It is established that a more intensive process of Sb sublimation at annealing of X-ray amorphous films in both a vacuum and a nitrogen atmosphere, connected with lower activation energy of free Sb sublimation in comparison with crystalline films.

Authors : E. V. Makhonina(1), A. E. Medvedeva(1), L. S. Maslennikova(1), A. M. Rumyantsev(2), Yu. M. Koshtyal(2), Yu. A. Politov(1), V. V. Volkov(1), V. S. Pervov(1), I. L. Eremenko(1)
Affiliations : (1) Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow, Russia; (2) Ioffe Physico-Technical Institute, Russian Academy of Sciences, St Petersburg, Russia

Resume : In recent years, the demand for the large-scale rechargeable batteries is growing rapidly. Lithium-ion batteries are the best choice for this purpose; but they still need to have a better cycling stability and safety at a lower price. Cathode materials composed of different electrochemically active compounds can be very promising inasmuch as the compounds can complement each other, compensate the drawbacks, and offer their advantages. Different combinations and ratios of LiNi0.8Co0.2O2, LiNi0.8Co0.15Al0.05O2, LiMn2O4, Li2MnO3, and LiFePO4 active materials were used for formation of composite cathode materials. The blends of single-phase powders were exposed to ultrasonic fields of different energy density. Li-rich composites including composites with core-shell structures in the Li-Ni-Co-Mn-O system were obtained by coprecipitation and sol-gel methods. The materials obtained were studied by X-ray powder diffraction, chemical analysis, TEM and SEM microscopy with cross-sectional composition analysis, electron diffraction, XPS measurements, DSC, and electrochemical tests. The ultrasonically treated composites have shown a better rate capability and cyclability than the initial compounds and reference blends of the same compositions. Taking into account the simple preparation method, those are the factors in favor of the use of these composites in the large-scale batteries. The Li-rich core-shell structures obtained have shown a good cyclability and very high rate capabilities (up to 62%-capacity retention at 8C rate). A part of this work was supported by the RF President’s Grants for Young Scientists MK-150.2017.3; the works on Li-rich oxides were supported by the Russian Science Foundation, Grant # 17-13-01424.

Authors : Samuel Quéméré 1, Togzhan Nurmukanova 1, Thierry Guizouarn 1, François-Xavier Lefèvre 2, Mathieu Pasturel 1, Stéphane Cordier 1, Pierric Lemoine 1
Affiliations : 1 Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes 1, Campus de Beaulieu, Rennes, France 2 Laboratoire CEISAM, UMR 6230 CNRS-Université de Nantes, Nantes, France

Resume : Ten ternary phases were reported in the Ni-Nb-P ternary diagram: NiNb4P, Ni1.66Nb2.5P0.84, Ni4Nb5P4, NiNbP, Ni2Nb2P3, NiNbP2, Ni2NbP, Ni1.5Nb0.5P, Ni4.5NbP0.5 and Ni4NbP16. Surprisingly, only few studies dealt on the properties of these materials. In order to increase the knowledges on this rich ternary diagram, we have decided to determine the (thermo)electrical properties of the NiNbP, Ni4Nb5P4, and Ni2Nb2P3 compounds. NiNbP crystallizes in the TiNiSi-type (Pnma, a = 6.113(1) Å, b = 3.582(1) Å, c = 7.109(1) Å). Ni4Nb5P4 presents a singular structure (Cu5Nb5Si4-type, I4/m, a = 9.932(1) Å, c = 3.526(1) Å), where the existence of Ni4 tetrahedral and Nb6 octahedral clusters form infinite chains along the c-axis. Ni2Nb2P3 crystallizes in its-own structure type (P63/m, a = 9.989(1) Å, c = 3.379(1) Å), a variant of the Cr12P7-type where Ni and Nb atoms are located on the different Cr sites and where the 2d site, empty in Cr12P7, is occupied by P atoms in Ni2Nb2P3. In this work, a three steps synthesis process was used: (i) high-temperature reaction of pure elements in silica tubes, (ii) annealing at high temperature of the samples, and (iii) densification of the resulting powder by using Spark Plasma Sintering technique. This later allow to reach high density pellets necessary to determine accurately the (thermo)electrical properties. The synthesis methods, XRPD analyses and preliminary resistivity, Seebeck coefficient and specific heat results will be presented.

Authors : Sungyun Lee, Sollee Kim, Kammari Sasidharachari, Sukeun Yoon*
Affiliations : Division of Advanced Materials Engineering, Kongju National University, Chungnam 31080, Republic of Korea

Resume : The technology development of Li-ion batteries is a key trend in high energy, high rate capability, high safety, and long cycle life. In particular, in order to expand electrochemical performance in Li-ion batteries, it needs to improve the performance of active material in negative electrode. In addition, it is necessary to develop a new anode active material having a specific capacity more than twice that of the currently used carbon materials. In this point, Si alloy anode materials have interested due to its high theoretical specific capacity (~4,000 mAh g-1). Despite its attractive feature, the use of Si alloy anode in practical Li-ion batteries is still limited by the severe capacity fading due to a volume change that occurs during lithium ion intercalation/deintercalation. To overcome this problem, composite materials with carbon material have studied to accommodate volume expansion and improve electrical conductivity. We will present here that dual conductive effect of nitrogen-doped carbon with metal matrix for Si nanoparticle and investigate their use as Li-ion batteries anode materials.

Authors : Jeong-Hyun Park, Parthiban Ramasamy, Soonhyun Kim, Young Kwang Kim, Vignesh Ahilana, Sangaraju Shanmugama, Jong-Soo Lee*
Affiliations : Department of Energy Systems Engineering, DGIST, Daegu 711-873, Republic of Korea

Resume : Recently, many efforts have been made to tune the photocatalytic properties of the semiconductor to improve the efficiency of the photocatalytic water decomposition reaction. The use of co-catalyst has been proven as a possible alternative to improve the separation of photogenerated electrons and holes greatly. We present a new synthesis method for the fabrication of hybrid metal-Cu2S (M=Pt, FePt) nanocrystals (HNs). Metal nanoparticles (M=Pt, FePt) act as seeds for the growth of the dumbbell shaped metal-Cu2S HNs. The metal-Cu2S HNs were investigated in photocatalytic hydrogen generation as effective co-catalysts on TiO2. The Pt-Cu2S/TiO2 catalyst showed higher hydrogen generation rate compared with a pure TiO2 catalyst. This enhancement is attributed to the synergetic effects between the Cu2S and Pt, which significantly improves the light absorption ability and the charge separation activity.

Authors : Kammari Sasidharachari1, Sollee Kim, Sungyun Lee, Sukeun Yoon*
Affiliations : Division Advanced Material Engineering, Kongju National University ,Cheonan Chungnam 31080 , South Korea

Resume : Alternative energy sources are attracting high attention due to the depletion and environmental problems of fossil fuels. Among them, Li-ion batteries are used as the most important power source because they have high energy density, long cycle life, and absence of memory effect. The rapid development of mobile, automotive and stationary storage applications requires further gravimetric/volumetric energy density, long-term use, and safety issues, however, Li-ion batteries do not meet their needs. In this point, many researchers have studied rechargeable metal-air batteries using highly efficient catalysts because of high theoretical energy densities. However, almost rechargeable metal-air batteries are still suffering from slow rates of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which results in large discharge-charge over-potential. To reduce over-potentials for both ORR and OER, recently, the mixed valence transition metal oxides are emerging potential candidates for bifunctional catalysts due to their high abundance, ease of preparation and good redox stability in alkaline solutions. In this study, we will present hydrothermal synthesis without any surfactant assistance to obtain spinel structural metal oxide nanoparticles. The as-synthesized samples were explored as a bifunctional catalyst for rechargeable Zn-air batteries that exhibits enhanced electrochemical properties.

Authors : Zhe Li, Haidong Bian, Yang Yang Li
Affiliations : Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong, China

Resume : Here we report a novel type of hierarchical mesoporous SnO2 nanostructures fabricated by a facile anodization method in a novel electrolyte system (an ethylene glycol solution of H2C2O4/NH4F) followed by thermal annealing at a low temperature. The SnO2 nanostructures thus obtained feature highly porous nanosheets with mesoporous pores well below 10 nm, enabling a remarkably high surface area of 202.8 m2/g which represents one of the highest values reported to date on SnO2 nanostructures. The formation of this novel type of SnO2 nanostructures is ascribed to an interesting self-assembly mechanism of the anodic tin oxalate, which was found to be heavily impacted by the anodization voltage and water content in the electrolyte. The electrochemical measurements of the mesoporous SnO2 nanostructures indicate their promising applications as lithium-ion battery and supercapacitor electrode materials.

Authors : Joonam Park, Williams Agyei Appiah, Seoungwoo Byun, Dahee Jin, Myung-Hyun Ryou, and Yong Min Lee
Affiliations : Department of Energy Systems Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST); Department of Chemical and Biological Engineering, Hanbat National University

Resume : Lithium-ion batteries (LIBs) have already been adapted for the applications of electric vehicles (EVs) and energy storage systems (ESSs) due to their high power density (~1500 W/kg), high energy density (~250 Wh/kg), and long cycle life among secondary batteries. However, tens of years or thousands of cycles are too long to evaluate the electrochemical performance or reliability of large-format LIBs. In addition, because high-current cyclers are much more expensive compared to those for small LIB cells for IT applications, available channels for long-term tests are strictly limited. That is why high-level modeling and simulation technologies should be developed for the battery society. In this study, we propose a new semi-empirical cycle life model for predicting long-term cycle life by devising an electrolyte depletion function for the first time. As a result, we can predict capacity losses depending on operating conditions such as c-rate and depth-of-discharge (DOD), which should be pre-estimated before building up the battery management system for EVs and ESSs application.

Authors : Sonal Singh, Rishabh Sharma
Affiliations : Deen Dayal Upadhyaya College, Dwarka, University of Delhi, New Delhi 110078, India; Thin Film Laboratory, Department of Physics, Indian Institute of Technology, New Delhi-110016 , India.

Resume : In this study, undoped and Nickel doped α-Bismuth oxide (Ni-Bi2O3) powder were synthesized by simple precipitation method. The resulting samples were characterized by SEM, EDAX, XRD, UV–vis and PL spectroscopy. EDX and XRD results indicated that Ni atoms were incorporated into the framework of the α-Bi2O3 in a highly dispersed way. The SEM characterizations revealed rod shape microstructures of the undoped Bi2O3 photocatalysts, while the Ni-doped product consisted of distorted or broken rod microstructures. Photoelectrochemical (PEC) study plainly demonstrated the improved current density for Ni-doped sample compared to its pure counterpart. The photocatalytic activities of these samples were evaluated on the photocatalytic removal of MB under simulated solar light irradiation. The Density Functional theory (DFT) study clearly revealed the formation of intermediate band in Ni-Bi2O3, supported by PL, which was responsible for the high efficiency of PEC and photocatalytic efficiency. The experimental results were rationalised by assuming that Ni atom serves as shallow trapping sites, greatly enhancing the activity of the photocatalyst.

Authors : Sylvain Le Tonquesse,Samuel Queméré,Thierry Guizouarn,Valérie Demange,Carmelo Prestipino,Mathieu Pastirel
Affiliations : 'Institut des Sciences Chimiques de Rennes' University of Rennes 1 CSM

Resume : Thermoelectric devices are developed for the transformation of wasted heat into electricity. Despite their promises, their low efficiency and elevated cost are nowadays limiting their widespread use. Intensive researches are currently going on to make them industrially viable by improving their efficiency. Skutterudites are among the best materials since they feature a high thermopower as well as a good electrical conductivity [1]. However their thermoelectric figure of merit ZT remains weak due to the high lattice thermal conductivity. Insertion of ‘rattling’ atoms in the voids of the crystal structure, doping and nanostructuration are efficient ways to reduce the latter while leaving the excellent electronic properties unchanged [2,3]. Another drawback of these compounds is their difficult synthesis requiring rather long heat treatments (around 2 weeks) at elevated temperature (around 1050 K) with intermediate milling and pelletizing [3]. We will report how we succeed in obtaining pure CoSb3 skutterudite at lower temperature (843 K) within short time (4 days) in the shape of powders with average grain size in the sub-micron range which is beneficial to reduce the thermal conductivity of the final sintered material. Its preliminary thermoelectric properties, measured on spark plasma sintered pellets, will be presented. [1] J. Peng et al., J. Alloys Compd., 426 (2006) 7 [2] X. Shi et al., J. Am. Chem. Soc., 133 (2011) 7837 [3] E. Alleno et al., J. Alloys Compd., 692 (2017) 676

Authors : Jiyue Wu, Amit Mahajan, Haixue Yan and Mike J Reece
Affiliations : School of Engineering & Materials Science, Queen Mary University of London, Mile End Road, E1 4NS, London, United Kingdom

Resume : Above depoling temperature Td, Bi0.5Na0.5TiO3 (BNT) shows relaxor ferroelectric behaviour which is good for high power energy storge in capacitances. The Td of BNT is above 100 C. To use BNT for energy storage application, the BNT-based materails should show relaxor behaviour at room temperature. In this paper, single phase Li and Sr co-substituted BNT ceramics were prepared. The materials show relaxor ferroelectric loops at room temperature with energy density up to 1 J/cc, which can be attributed to the phase transitions produced by chemcial pressure that was induced by co-substitution at A-site in BNT-based ceramics.

Authors : Rishabh Sharma 1, Nisha Kodan 2,Vinod Poonia 2, S. N. Sharma 3, O. P. Sinha 1
Affiliations : 1 Amity Institute Of Nanotechnology, Amity University,UP,Sector-125, Noida-201303,India; 2 Thin Film Laboratory, Department of Physics, Indian Institute of Technology, New Delhi-110016, India; 3 Electronic Materials Division, CSIR- National Physical Laboratory, New Delhi-110012

Resume : Simple technique for thin film deposition on silicon substrate through spin coating a precursor and followed by thermal decomposition process is used for synthesizing TiO2 thin films. Arc plasma assisted in-flight gas phase growth system is used to synthesize size selected Pd and Pd-Carbon core shell (Pd-C) nanoparticles which are directly deposited on TiO2 thin films. In-flight selection of 20 nm Pd or Pd-C nanoparticle is done by using electrolyzer and differential mobility analyzer assembly. Size of nanoparticles i.e. ~20 nm is confirmed by TEM micrographs. Also TEM images confirm the formation of carbon shell around Pd nanoparticles indicating core-shell structure. XRD analysis and Raman spectroscopy confirms the formation of pure anatase phase of TiO2. Raman spectrum of Pd-C-TiO2 also indicate the graphitic nature of carbon in Pd-C. Reduction in PL intensity of Pd-TiO2 & Pd-C-TiO2 sample in comparison to pure TiO2 films which indicates the decrease in recombination rate of charge carriers, this effect is attributed to surface plasmon resonance in Pd and Pd-C nanoparticles. Photoelectrochemical (PEC) measurements indicate the best PEC performance of Pd-C-TiO2 among all three samples i.e. TiO2, Pd-TiO2 & Pd-C-TiO2. This enhancement in PEC activity of Pd-C-TiO2 sample can be attributed to suppressed recombination rate, increase charge carrier density and hydrogen interaction improvement due to carbon layer.¬

Authors : M. Romio, I. Abrahams, A. Trifonova
Affiliations : School of Biological and Chemical Science, Queen Mary University of London, Mile End Rd, London E1 4NS, United Kingdom Center for Low-Emission Transport, Electric Drive Technologies, AIT Austrian Institute of Technology Gmbh, Giefinggasse 2, 1210 Vienna, Austria.

Resume : Mg-ion batteries are being considered as a promising alternative to lithium technologies due to their safety, low cost and chemical properties. At the present time, research is mainly focused on finding a suitable cathode and a good electrolyte/cathode combination. The right battery components would permit cations to be reversibly intercalated without significantly modifying the cathodic lattice achieving high kinetics and conductivity. In the last ten years, phosphate compounds have been investigated as promising cathode materials thanks to their poly-anionic structure, excellent thermal stability and good intercalation/de-intercalation performance. In the present work manganese doped magnesium phosphates ((Mg1-xMnx)3(PO4)2, 0.00 ≤ x ≤ 1.00) have been synthesized and characterized in order to assess their suitability as new cathode materials for Mg rechargeable batteries. Three different preparation methods were investigated: solid-state, co-precipitation and sol-gel methods. Two main structures are found in this system, the Mg3(PO4)2 structure in space group P21/n and the β-Mn2(PO4)2 in space group P21/c. The structural, thermal and magnetic properties of the system are reported. Keywords: Magnesium secondary battery; cathode; magnesium; phosphate.

Authors : Seon-Hwa Lee and Yang-Kook Sun*
Affiliations : Department of Energy Engineering, Hanyang University, Seoul, 133-791, South Korea.

Resume : Li–O2 batteries have a major obstacle regarding the large overpotential upon charging that results from the low conductivity of the discharge product.1-3 Thus, various redox mediators (RMs) have been widely studied to reduce the overpotential upon the charging process; this should help promote the oxidation of Li2O2. However, since RMs degrade the Li-metal anode through a parasitic reaction between the RM and the Li metal, a solution is needed to rectify this phenomenon. Here, we propose an effective method to prevent the migration of the RM toward the anode side of the lithium metal by using a modified separator with a negatively-charged polymer. When DMPZ (5,10-dihydro-5,10-dimethylphenazine) is used as the RM, we find that the modified separator suppressed the migration of DMPZ toward the counter electrode of the Li-metal anode; this is investigated by a visual redox couple diffusion test, morphological investigation, and X-ray diffraction study. This advanced separator effectively maximizes the catalytic activity of the redox mediator. Li–O2 batteries using both a high concentrated DMPZ and the modified separator exhibit improved performances and maintain 90% of the round-trip efficiency up to the 20th cycle.

Authors : D.-W. Jun, G.T. Park, Y.-K. Sun*
Affiliations : Department of Energy Engineering, Hanyang University, Seoul, 133-791, South Korea

Resume : A spherical stoichiometric LiNiO2 cathode material, composed of compactly packed nanosized primary particles, was prepared and cycled at different cutoff voltages to demonstrate the effect of phase transitions during Li deintercalation/intercalation on the Li-ion intercalation stability of LiNiO2. The capacity retention was dramatically improved by suppressing the H2 → H3 phase transition at 4.1 V, such that 95% of the initial capacity (164 mAh g−1) was retained after 100 cycles when cycled at 4.1 V. At 4.2 and 4.3 V, continuous capacity loss (81% of 191 mAh g−1 at 4.2 V and 75% of 232 mAh g−1 at 4.3 V after 100 cycles) was observed during cycling, and these electrodes underwent extensive structural damages (micro-, hairline and nanoscale cracks observed by transmission electron microscopy) from the repeated lattice contraction and expansion accompanying the H2 → H3 transition, in agreement with the cycling data.

Authors : Un-Hyuck Kim, Jae-Hyung Kim, Yang-Kook Sun*
Affiliations : Department of Energy Engineering, Hanyang University, Seoul 133-791, South Korea

Resume : Al is introduced into a compositionally graded cathode with average composition of Li[Ni0.61Co0.12Mn0.27]O2 (FCG61) whose Ni and Mn concentrations are designed to vary continuously within the cathode particle. The Al-substituted full concentration gradient (Al-FCG61) cathode is tested for 3000 cycles in a full-cell, mainly to gauge its viability for daily charge/discharge cycles during the service life of electric vehicles (≈10 years). The Al-substitution enables the Al-FCG61 cathode to maintain 84% of its initial capacity even after 3000 cycles. It is demonstrated that the Al-substitution strengthens the grain boundaries, substantiated by the mechanical strength data, thereby delaying the nucleation of microcracks at the phase boundaries which is shown to be the main reason for the cathode failure during long-term cycling. It also shows that the Al-substitution decreases the cation mixing and suppresses the deleterious formation of the secondary phase that likely initiates the microcracks. Concurrently, both the FCG61 and Al-FCG61 cathodes were cycled at 100% DOD for 3000 cycles unlike the already commercialized NCA cathode, which is limited to only 60% DOD for long-term cycling. The proposed Al-FCG61 cathode is cycled at 100% DOD for 3000 cycles to fully utilize its available capacity for maximum energy density and subsequent reduction in cost of the battery.

Authors : Tae-Yeon Yu, Doron Aurbach* and Yang-Kook Sun*
Affiliations : T.-Y. Yu, Prof. Y.-K. Sun Department of Energy Engineering Hanyang University Seoul 133-791, Republic of Korea; Prof. D. Aurbach Department of Chemistry Bar Ilan University Ramat-Gan 52900, Israel

Resume : The development of high-energy and high-power density sodium-ion batteries is a great challenge for modern electrochemistry. The main hurdle to wide acceptance of sodium-ion batteries lies in identifying and developing suitable new electrode materials. We present a composition-graded cathode with average composition Na[Ni0.61Co0.12Mn0.27]O2, which exhibits excellent performance and stability. In addition to the concentration gradients of the transition metal ions, the cathode is composed of spoke-like nanorods assembled into a spherical superstructure. Individual nanorod particles also possess strong crystallographic texture with respect to the center of the spherical particle. Such morphology allows the spoke-like nanorods to assemble into a compact structure that minimizes its porosity and maximizes its mechanical strength while facilitating Na+-ion transport into the particle interior. Micro-compression tests have explicitly verified the mechanical robustness of the composition-graded cathode and single particle electrochemical measurements have demonstrated the electrochemical stability during Na+-ion insertion and extraction at high rates. These structural and morphological features contribute to the delivery of high discharge capacities of 160 mAh (g-oxide)-1 at 15 mA g -1 (0.1 C-rate) and 130 mAh g -1 at 1500 mA g -1 (10 C-rate). The work is a pronounced step forward in the development of new Na ions insertion cathodes with concentration gradient.

Authors : Hun Kim, Won-Jin Kwak, Doron Aurbach*, Yang-Kook Sun*
Affiliations : Hun Kim, Won-Jin Kwak, Yang-Kook Sun* Department of Energy Engineering, Hanyang University, 133-791, Republic of Korea. ; Doron Aurbach* Department of Chemistry, Bar Ilan University, Ramat-Gan, 52900, Israel.

Resume : After many years of successful and disappointing results, the field of Li–O2 research seems to have reached an equilibrium state. The extensive knowledge that has accrued through advanced analytical studies enables us to reveal the weaknesses of the Li–O2 battery. It is now clear that the instability of the cell components toward extreme conditions existing during cell operation leads to early cell failure as well. One serious challenge is the high oxidation potential applied during the charging process. Redox mediators may reduce the over-potential and, therefore, improve the efficiency and cycle performance of Li–O2 cells. Their use in Li–O2 cells is indispensable. We have previously shown that LiI can indeed behave in such a manner; however, it also promotes the formation of side products during cell operation. We have, therefore, embarked on a comprehensive study of lithium halide salts as electrolytes for use in Li–O2 cells. We examine herein the effect of other components in the cell, such as solvents and contaminants, on the lithium halide salt activity. Based on the electrochemical behavior and the identity of the final cell products under various conditions, we can glean substantial information regarding the detailed operation mechanisms for each specific case. We have concluded that low concentration of LiBr in diglyme solution can improve the cell performance with fewer side effects than LiI. With LiBr, only the desired Li2O2 is formed during discharge. During charge, the bromine redox couple (Br-/Br3-) can reduce the oxidation potential to only 3.5 V. Higher efficiency and better cycle performance of cells containing LiBr show that the electrolyte solution is the key to a successful Li–O2 battery.

Authors : J. H. Kang, D. aurbach and Y. K. Sun
Affiliations : Department of Energy Engineering, Hanyang University Department of Chemistry, Bar-Ilan University

Resume : Real cell capacities of Li­air batteries are very small and, since only small­scaled cathodes are currently evaluated, it is difficult to predict the properties of large-scaled cathodes and batteries, thus testing and judging real practical trials related to this battery technology.1-­3 In this report, we report on fabrication, operation and test of pouch­type Li­air batteries using 3×5 cm2 sized cathodes, in which we intend deal with higher capacity (mAh) of the cathodes, compared to most previous studies in the field. With the relatively large­scaled cells, operating at high current density and capacity, we could recognize some significant problems that may not be remarkable in small cells. In relatively large scaled battery as those explored in this work issues related to non­uniform current distribution, mechanical and electronic integrity of cathodes are much more influencing compared to small scaled battery. Therefore, problems such as lithium dendrites formation and non­uniform deposition of oxygen reduction product become severe. This study can help to determine which parameters are the most important for developing real Li­air batteries. References 1. K. M. Abraham, Z. Jiang, J. Electrochem. Soc. 1996, 143, 1. 2. H. G. Jung, J. Hassoun, J. B. Park, Y. K. Sun, B. Scrosati, Nature Chemistry 2012, 4, 579. 3. 3. M. M. O. Thotiyl, S. A. Freunberger, Z. Peng, Y. Chen, Z. Liu, P. G. Bruce, Nature Materials 2013, 12, 1050.

Authors : Min-Jae Choi, and Yang-Kook Sun*
Affiliations : Department of Energy Engineering, Hanyang University

Resume : Silicon (Si)-based materials have attracted significant research as an outstanding candidate for the anode material of lithium-ion batteries. However, the tremendous volume change and poor electron conductivity of bulk silicon result in inferior capacity retention and low Coulombic efficiency. Designing special Si with high energy density and good stability in a bulk electrode remains a significant challenge. In this work, we introduce an ingenious strategy to modify micro silicon by designing a porous structure, constructing nanoparticle blocks, and introducing carbon nanotubes as wedges. A disproportion reaction, coupled with a chemical etching process and a ball-milling reaction, are applied to generate the desired material. The as-prepared micro silicon material features porosity, small primary particles, and effective CNT-wedging, which combine to endow the resultant anode with a high reversible specific capacity of up to 2028.6 mAh g-1 after 100 cycles and excellent rate capability. The superior electrochemical performance is attributed to the unique architecture and optimized composition

Authors : Evgeny LEGOTIN 1, Arlavinda REZQITA 1, Frank BÄRHOLD 2, Franz WINTER 3, Atanaska TRIFONOVA 1
Affiliations : 1 AIT Austrian Institute of Technology GmbH, Electric Drive Technologies, Center for Low-Emission Transport, Giefinggasse 2, 1210 Vienna, Austria; 2 Andritz AG, Eibesbrunnergasse 20, 1120 Vienna, Austria; 3 Technische Universität Wien, Institute of Chemical Engineering, Getreidemarkt 9, 1060 Vienna, Austria

Resume : NMC111 (LiNi1/3Mn1/3Co1/3O2) is one of a few Li-ion battery cathode materials massively available in the market. As a cathode material, it combines a number of strengths such as high energy and power densities, safety and good lifetime stability. At the same time, the production costs of NMC are still high. Using a suitable high-throughput and continuous spray technique could reduce its manufacturing costs. Previously we reported a new route for large-scale production of NMC powder material, viz. spray-roasting of nickel, cobalt and manganese chloride solution with subsequent lithiation of the resulting oxide product [1]. In the current study, we show the influence of treatment conditions (such as lithiation temperature or milling regime) on electrochemical performance of NMC cathode material. The obtained materials were characterized by multiple physicochemical methods (XRD, SEM, laser particle size analysis, BET). The electrochemical study included cyclovoltammetric tests, galvanostatic cycling and EIS measurements. The correlation of physicochemical data and electrochemical behavior of the materials was explained. Acknowledgement: We are thankful to the Austrian Research Promotion Agency (FFG) for financial promotion of this work. References: 1. K. Fröhlich, E. Legotin, F. Bärhold, A. Trifonova. New large-scale production route for synthesis of lithium nickel manganese cobalt oxide. J. Solid State Electrochem. (article accepted for publication)

Authors : Tae Woo Kim, Muhammad Sohail, and Hyunuk Kim
Affiliations : Energy Materials Laboratory, Energy Efficiency and Materials Research Division, Korea Institute of Energy Research,152 Gajeong-ro, Yuseong-gu, Daejeon 34129, Korea.

Resume : A novel photocatalyst of MIL-125-NH2(Ti-MOF)/ZnCr-LDH hybrid materials has been developed for H2 production from water under visible light irradiation. The hybrid materials was synthesized by growing Ti-MOF in a colloidal suspension of ZnCr-LDH nanosheets under hydrothermal reaction. The obtained hybrid materials were systematically characterized by various tools such as powder XRD, FESEM, TEM/EDX, BET, UV-Vis, PL and so on. According to powder XRD and FESEM, the crystallinity and morphology of Ti-MOF after the hybridization with ZnCr-LDH nanosheets became lower and irregular in comparison with pure Ti-MOF. This result implies that ZnCr-LDH nanosheets limit the growth of Ti-MOF. The hybrid materials were tested for photocatalytic H2 production under visible light irradiation (λ≥420 nm). From the test, we found that the hybrid material has better performance more than two times than pure Ti-MOF. Interestingly, in this work the highly efficient H2 production of the present hybrid material was achieved without a co-catalyst such as Pt. The improved photocatalytic activity results from the increase of the lifetime of the photoinduced electrons and holes by strong coupling of two materials and their proper band alignment. In addition, the Ti-MOF after hybridization with LDH improved more chemical stability than that before hybridization. In this work, we will discuss in detail about synthesis procedure, structural formation, photocatalytic ability, and mechanism for the present hybrid materials.

Authors : Youngkwon Kim*, Ji Eun Park, Seunghwan Jeon, Yun-Suk Ko, Ji-Sang Yu
Affiliations : Advanced Batteries Research Center, Korea Electronics Technology Institute (KETI), Korea

Resume : The all vanadium redox flow battery (VRFB) is considered one of representative electrochemical storage system for large scale renewable and grid energy storage system due to unlimited capacity, design flexibility, and safety. The VRFB stores energy in two electrolyte containing different redox couples, V2+/V3+ and VO2+/VO2+, which provide the potential difference by redox reaction at the surface of electrode. Since sulfuric acid solution is used as the support electrolyte in VRFB, carbon felts are chosen as the electrodes because of their pore structure, high strength and broad potential window. However, poor electrochemical activity of carbon materials limits their widespread use in VRFB. Most of electrode material studies focused on positive electrode due to electrochemical kinetic limitations of VRFB related to VO2+/VO2+ reactions. However, recently a few studies pointed out the negative electrode overpotential is much higher than that of positive electrode. In this study, we modified carbon felt electrode by combination of magnesium ion solution treatment and thermal treatment to enhance the amount of surface oxygen functional group. This modified carbon felt electrode shows higher V2+/V3+ electrochemical reaction properties, which is considered that reduced hydrogen evolution and improve reaction kinetics. The full cell with modified carbon felt as anode shows higher energy efficiency as well as discharge capacity retention than that of conventional thermal treated carbon felt as anode. Therefore, this simple electrode modification could be a new candidate for electrode pretreatment method for VRFB.

Authors : Franciszek Dąbrowski, Krzysztof Jan Kurzydłowski, Łukasz Ciupiński, Joanna Zdunek, Jakub Kruszewski, Rafał Zybała, Andrzej Michalski
Affiliations : Warsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska St. 141, 02-507 Warsaw, Poland

Resume : In this work, the microstructure and thermoelectric properties of mechanically alloyed and pulse plasma sintered, n and p type doped with B4C nanoparticles, β-FeSi2 were investigated. Selected base materials Fe0.92Mn0.08Si2, Fe0.97Co0.03Si2, FeSi1.93Al0.07, FeSi1.95P0.05 enriched with 1% [wt] B4C nanoparticles. This reaseach evaluates the influence of addition of B4C nanoparticles for lowering thermal conductivity thus enhancing thermoelectric performance of β-FeSi2. The results of XRD measurements and SEM observations confirmed for all samples a nearly complete transformation from α and ε into β phase after annealing in 1123 K for 36 ks of the consolidated samples. The measured thermoelectric parameters, (the Seebeck coefficient, electrical, and thermal conductivity) showed a consistent dependence on the test temperature with desirable reduction of thermal conductivity for the entire range of the temperatures of practical meaning.

Authors : Alexander Platonenko, Dmitri Bocharov, Sergei Piskunov, Yuri F. Zhukovskii
Affiliations : University of Latvia Institute of Solid State Physics, Kengaraga 8, Riga LV-1063

Resume : We have calculated the electronic structure of WS2(0001) nanosheets with thickness varying between 1 and 10 monolayer (ML) found to be remarkably suitable for photocatalytic water splitting under influence of solar light. The edges of their band gaps correspond to the range of visible spectrum between the violet (1 ML) and red (10 ML) ranges of visible spectrum (2.79 and 1.58 eV, respectively) since the band gap decreases with an increasing nanosheet thickness. The top of the valence band and the bottom of the conduction band of considered WS2 nanosheets have been properly aligned relative to the oxidation and reduction potentials separated by 1.23 eV necessary for water splitting under visible light irradiation. Ab initio calculations reported here have been performed within the formalism of hybrid Density Functional Theory and Hartree-Fock method when using HSE06 Hamiltonian properly adapted and verified relatively to properties of WS2 bulk and nanosheets. When modifying their structure by single vacancies of S and W atoms or isoelectronic dopants (Mo, O, Se) no energy level distribution inside the band gap has been found, only “smeared” bands arranged either below the top of the valence band or above the bottom of the conduction band. The highest solar energy conversion efficiency (15-18%) has been achieved for 2 ML thick (stoichiometric) WS2(0001) nanosheet with oppositely directed dipole moments possessing band gap of 2.0-2.2 eV (yellow-green range of visible spectrum).

Authors : WonBae Ko 1, Dasong Choi 1, Choonghyun Lee 1, Jungyup Yang 2, Gapsoo Yun 3, and JinPyo Hong 1*
Affiliations : 1 Research Institute of Convergence of Basic Science, Novel Functional Materials and Device Laboratory, Department of Physics, Hanyang University, Seoul 133-791, Korea; 2 Department of Physics, Kunsan National University, South Korea; 3 Samsung Display IT development 465, Beonyeong-ro, Seobuk-gu, Cheonan-si, Chungcheongnam-do, South Korea;

Resume : Wearable energy harvesting devices offer great opportunities to deploy advanced feasible electronics that are capable of at least offsetting, or replacing, the reliance of portable electronics on traditional power supplies, such as batteries. Harvesting energy from the living environment of human motions is an effective approach for sustainable, reliable, and maintenance-free energy source. To date, various types of triboelectric nanogenerators (TENGs) based on 2-dimensional (2D) textile platforms have been successfully developed to correlate harvesting energy that originates from human motions such as vibration, rotation, and displacement, etc. However, the 2D textile-based TENGs might create geometric deformation, resulting in providing the low current density of the interface layer of triboelectric materials. In addition, the hybridization of wearable clothes with 2D textile platform-based TENGs may limit their flexibility, mechanical robustness, and lightness. Here, we demonstrate a rationally designed one dimensional (1D) conductive yarn-based TENGs by utilizing the contact electrification between 1D conductive yarns and 2D conductive textile. The surface structure configuration of 1D conductive yarn was manipulated by an Aluminum (Al) layer and ZnO nanoparticles (NPs). This energy harvesters contributes to the increase in the surface area and improvement in the electrical power output performance. Furthermore, finite element simulation by COMSOL Multiphysics was performed to investigate the triboelectric charge distribution under the compressive force under various surface structure configurations. A high output voltage, current density, and energy volume density reached 60 V, 9.5 uA / cm2, and 0.5 mW / cm2 from the multi-stacked 1D conductive yarn based TENGs, respectively, while an output voltage and current density, and energy volume density of 15 V and 3 uA / cm2, and 0.15 mW / cm2 were obtained by the single conductive yarn based TENGs under the same conditions. The TENGs demonstrated a sustainable power source through the amount of conductive yarn and the number of stacks. This technology offers great potential and applicability in portable / wearable electronics, opening the chapter of nanogenerators impacting people’s lives positively.

Authors : Sang-Min Lee*, Gumjae Park, Hae-Young Choi, Jeong-Hee Choi, Jong-Wook Bae
Affiliations : Battery Research Center, Korea Electrotechnology Research Institute

Resume : The current level of performances of Lithium Ion Batteries (LIBs) is not enough to meet commercial demands for new applications(xEV, ESS), in particular, with respective to energy density. Graphite and hard carbons are commonly used as a negative electrode material for LIBs, but higher-capacity alternatives are being consistently sought due to their limited capacity as an anode material of next generation LIBs for large-scale power applications. Recently, various Si, and Sn based compound including transition metal oxide, multiphase alloy, and intermetallic compounds have been extensively studied as alternatives to the existing carbon based anode material. These materials show much higher capacities than those of carbonaceous material. However, they are suffering from huge lattice volume change (4.4Li Si  Li4.4Si, V>300%) through conversion reaction mechanism during Li insertion, which results in poor cycle life of LIBs. In this respect, metal phosphides have been alternatively suggested as a promising anode material for their reversibility, and large amount of lithium uptake at relatively low potential. Obviously, the degree of difference in electronegativity between constituting elements inevitably dtermines whether the metal phosphides obey topotactic reaction mechanism during lithiation and delithiation, which can be readily understood by considering the Gibbs formation free energy [1,2]. Basically, the metal rich phosphides have physical properties similar to those of ordinary metallic compounds like the carbides, nitrides, borides and silicides. They combine the properties of metals and ceramics, and thus are good conductors of heat and electricity, are hard and strong, and have high thermal and chemical stability [3,4]. In this work, we have synthesized new Si composite anode involving metal phosphide with topotatic reaction mechanism, while relating with electrochemical properties. We finally propose newly designed anode composed of metal phosphide based Silicon composite showing long durability and less swelling properties. References [1] Young-Ugk Kim, Churl Kyung Lee, Hun-Joon Sohn, and Tak Kang, Journal of The Electrochemical Society, 151 (2004) A933-A937 [2] Youngsik Kim, Haesuk Hwang, Chong S. Yoon, Min G. Kim, and Jaephil Cho, Adv. Mater.19 (2007) 92–96 [3] B. Aronsson, T. Lundstro¨m, S. Rundqvist, Borides, Silicides and Phosphides, Methuen, London and Wiley, New York, 1965. [4] D.E.C. Corbridge, 4th Ed., Studies in Inorganic Chemistry, vol. 10, Elsevier, Amsterdam, 1990.

Authors : Seunghoon Nam, Joonhyeon Kang, Jinyoung Kim, Seungmin Hyun, Yongjoon Park, Byungwoo Park
Affiliations : Korea Institute of Machinery and Materials

Resume : An oxygen-deficient black TiO2 with hierarchically-porous structure was fabricated by a simple hydrogen reduction as a carbon- and binder-free cathode, demonstrating superior energy density and stability. With the high electrical conductivity derived from oxygen vacancies or Ti3 ions, this unique electrode features micron-sized voids with mesoporous walls for the effective accommodation of Li2O2 toroid and for the rapid transport of reaction molecules without the electrode being clogged. In the highly-ordered architecture, toroidal Li2O2 particles are guided to form with a regular size and separation, which induces the most of Li2O2 external surface to be directly exposed to the electrolyte. Therefore, Li2O2 toroids grown from solution can be effectively charged by incorporating a soluble catalyst, resulting in a very small polarization. Furthermore, disordered nanoshell in black TiO2 is suggested to protect the oxygen-deficient crystalline core, by which oxidation of Ti3 is kinetically impeded during battery operation, leading to the enhanced electrode stability even in a highly-oxidizing environment under high voltage (~4 V).

Authors : Sollee Kim, Sungyun Lee, Hyerin Kim, Kammari Sasidharachari, Sukeun Yoon*
Affiliations : Kongju National University

Resume : Lithium-sulfur (Li-S) batteries have been considered as potential power sources for next-generation energy storage devices. Elemental sulfur (S8), with an operating potential of ~2.1 V vs. Li+/Li, accepts up to 16 electrons at room temperature. As a result, a sulfur cathode has a theoretical capacity of 1675 mAh g−1, which can provide a high theoretical gravimetric energy density of 2600 Wh kg−1 for Li-S batteries. Moreover, sulfur can be readily obtained as a common by-product of the petroleum refining process, and it is an environmentally friendly element compared with certain toxic transition-metal compounds. Despite these advantages, several major issues must be solved prior to the practical use of Li-S batteries. The low intrinsic conductivity of sulfur (5 × 10−30 S cm−1 at 25 oC) and the intermediate products (polysulfides, Li2Sm, 3 ≤ m ≤ 8) result in unstable electrochemical contact at the sulfur cathode electrode. Furthermore, the dissolved polysulfides participate in shuttle reactions between the anode and cathode during the charge-discharge process. These issues have definite effects on cycle life and system efficiency. Among the various strategies to address the issue of polysulfide dissolution, in this study, we systematically investigate the impact of iodide salts in organic electrolyte on electrochemical performance.

Authors : Siham Idrissi1, Omar Benabdallah1, Qiliang Wei2, Xiaohua Yang2, Zineb Edfouf1, Shuhui Sun2, Fouzia Cherkaoui El Moursli1
Affiliations : 1 Faculty of Sciences, Mohammed Vth University of Rabat, Morocco; 2 Institut National de la Recherche Scientifique, Quebec University, Canada

Resume : The development of efficient electrocatalysts for the oxygen reduction reaction (ORR) is a key issue for the commercialization of metal-air batteries. This latter have been targeted as a promising technology to meet the energy requirements for future electric vehicles and other energy-demanding devices. [1,2] Traditional Platinum-based catalyst exhibits high catalytic activity. However, the scarcity and high cost of Pt limit their large-scale production and commercialization. The search for alternative ORR catalysts has led to the development of many non-precious metal catalysts to replace the commercial expensive platinum/carbon catalyst for ORR. [3] Graphene is one of the most promising 2D materials in various technological areas owing to its interesting properties. [4] The aim of this work is to study the electro-catalytic properties of the prepared graphene based materials using the oxygen reduction reaction (ORR). In this paper, we report a facile synthesis for doping graphene with nitrogen (N-graphene), phosphorus (P-graphene) and nitrogen/phosphorus (PN-graphene). Composites with doped graphene were also synthesized: (Fe3O4/N-graphene and Co2P@CoNP-graphene). The obtained materials are characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA). Results of both structural and electrocatalytic measurements are compared and discussed. [1] G. Jin, S. Liu, Y. Li, Y. Guo, Z Ding, NANO. 11 (2016) 1650126. [2] J. B. Goodenough, Acc. Chem. Res. 46 (2013) 1053-1061. [3] W. Xia, A. Mahmood, Z.B. Liang, R. Zou, S. Guo, Angew. Chem. Int. Ed. 55 (2016) 2650-2676. [4] A. K. Geim, K.S. Novoselov. Nature Mater. 6 (2007) 183-191.

Authors : Min Seon Lee (a,b), Ji Sun Yun (a), Woon Ik Park (a), Jeong Ho Cho (a), Jong Hoo Paik (a), Yong Ho Park (b), and Young Hun Jeong (a*)
Affiliations : a. Electronic Convergence Materials Division, Korea Institute of Ceramic Engineering and Technology, South Korea b. Department of Material Science and Engineering, Pusan National University, South Korea

Resume : The piezoelectric/magnetostrictive {0.73Pb(Zr0.47Ti0.53)O3-0.27Pb[(Zn0.45Ni0.55)1/3Nb2/3]O3/ NiZnFe2O4} laminate composites with 2-2 continuity were investigated to obtain better magnetoelectric (ME) properties for ME energy harvesting applications. The 0.73Pb(Zr0.47Ti0.53)O3-0.27Pb[(Zn0.45Ni0.55)1/3Nb2/3]O3 (PZT-PZNN) and NiZnFe2O4 (NZF) thick films were formed by a conventional tape casting method. The high energy density PZT-PZNN thick film exhibited a good transduction coefficient (d33•g33) of 14,658 x 10-12 m2/N and the NZF film was also confirmed to have an excellent permeability of approximately 2000. The interdigitated electrode (IDE) pattern with a line configuration of width/space (100 μm/500 μm) was formed and successfully embedded to the PZT-PZNN laminates in order to introduce a longitudinal vibration mode by polarization along its length axes. The IDE embedded piezoelectric and magnetostrictive laminate composites with a thickness of approximately 800 μm were co-fired at 1080oC while no mechanical defects were observed on the sintered body. In particular, the specimen with a dimension of 14 mm x 45 mm revealed a highly good magnetoelectric coefficient of approximately 4.4 V•(cm•Oe)-1 at Hac=0.5 Oe. In addition, it showed large output power of 253 μW at resonance frequency of 60 Hz, which means almost twice as large as that of ME composites by transverse vibration mode.

Authors : Kyung-Hye Jung, So Jeong Kim, Ye Ji Son
Affiliations : Department of advanced materials and chemical engineering, Catholic University of Daegu, South Korea

Resume : Supercapacitors store their charge in the double layer at interfaces between electrodes and electrolyte. Electrical charges accumulate on the electrode surface, and thus it is essential to have large surface area and porosity of electrode materials for high energy storage performance. Carbon nanofibers are good candidate electrode materials due to their high surface area and interconnected pores. They are typically fabricated by thermal treatments (stabilization and carbonization) of electrospun precursor nanofibers such as polyacrylonitrile (PAN). Sacrificial pore generating agents are also added to improve the surface properties of carbon nanofibers. High thermal stability and free volume of 6FDA (4,4-hexafluoroisopropylidene diphthalic anhydride)-durene (2,3,5,6-tetramethyl-1,4-phenylenediamine) make it good candidate for carbon precursors. Carbon nanofibers derived from 6FDA-durene show high surface area and porosity without the use of pore generating agents. To further improve surface properties of carbon nanofibers, the surface of 6FDA-durene nanofibers were cross-linked using ethylenediamine vapor. FTIR spectroscopy showed that the amide groups are formed by the interaction between the imide groups of 6FDA-durene and the amine groups of a cross-linker. Carbon nanofibers were prepared by stabilization at 400 °C under air and carbonization at 800 °C under nitrogen. The conversion of both non-treated and cross-linked 6FDA-durene to carbon was confirmed by Raman spectroscopy. It was also shown that carbon nanofibers derived from 6FDA-durene consist mainly of disordered carbon. The mass uptake measured by quartz crystal microbalance (QCM) indicated that carbon nanofibers derived from cross-linked 6FDA-durene have high adsorption capacity, resulting in high surface area and porosity. Electrochemical performances were investigated by assembling coin-type cells with free-standing carbon nanofiber electrodes. Carbon nanofiber electrodes derived from cross-linked 6FDA presented higher specific capacitance compared to those from non-treated one due to their improved surface area and porosity.

Authors : Omar Benabdallah1, Siham Idrissi1, Xiaohua Yang2, Qiliang Wei2, Zineb Edfouf1, Shuhui Sun2, Fouzia Cherkaoui El Moursli1.
Affiliations : 1 Faculty of Sciences, Mohammed Vth University of Rabat, Morocco; 2 Institut National de la Recherche Scientifique, Quebec University, Canada.

Resume : Recently, many efforts have been made to develop an inexpensive and efficient catalyst for oxygen reduction reaction (ORR). This crucial component is essential for renewable energy devices, such as fuel cells and metal-air batteries. Among a non-precious metal based catalyst, Co3O4 is recognized as a promising ORR catalyst because of their high catalytic activity, environmental friendliness and low cost. In this study, we use a facile hydrothermal method to prepare Co3O4 and Co3O4/Graphene composite (Co3O4/G). This latter exhibits better catalytic activity including much more positive half-wave potential and higher limiting diffusion current than the pristine Co3O4. This result suggests that the interaction between Co3O4 and graphene plays an important role in the higher electrocatalytic activity of the composite.

Authors : Olga A. Krysiak1,2, Luzhu Xu3, Michael A. Pope3, Jan Augustynski1
Affiliations : 1 Centre of New Technologies, University of Warsaw, S. Banacha 2c, 02-097 Warsaw, Poland 2 College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, S. Banacha 2c, 02-097 Warsaw, Poland 3 Department of Chemical Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada

Resume : Titanium dioxide is widely studied material due to its potential applications in water photosplitting and decontamination of air and water. Several different methods of improving the efficiency and functionality of TiO2 has been tested. In this work, we have used large surface area thin film rutile electrodes decorated with molybdenum disulfide layer obtained by spreading assisted assembly method. Our choice is based on the fact that MoS2 and other transition metal dichalcogenides (TMDs) are known catalysts for hydrogen evolution reaction (HER). Prepared by us samples (and MoS2 layers themselves) were characterize with the use of scanning electron microscopy, atomic force microscopy, Raman spectroscopy and electrochemical methods. Photoelectrochemical activity of electrodes were measured in terms of current-voltage characteristics under dark and simulated sunlight irradiation. Finally, the photocatalytic properties were checked towards organic pollutant photo-decomposition. We found that MoS2/TiO2 electrodes can be succesully used to degradation of organic solution species under visible light irradiation and as an inexpensive photocatalyst for energy conversion able to secure H2 evolution without noble metals.

Authors : Jin-Ju Bae, Min-Gyeom Kim, Yong-Cheon Hong, In-Seok Seo, Tae-Whan Hong and Jong-Tae Son*
Affiliations : Department of Nano Polymer Science & Engineering, Korea National University of Transportation, Chungju, Chungbuk, 380-702, Korea ; Department of Material Science and Engineering, Korea National University of Transportation, Chung-ju 380-702, Republic of Korea

Resume : Ni-rich cathode materials have attracted an increasing amount of interest due to their low toxicity, relatively low cost and high capacity when compared to LiCoO2 [1]. By the way, the electrochemical properties are reduced such as rate capability and capacity retention because of HF attack from the chemical side reactions between cathode and electrolyte [2]. In this study, we attempt to reduce the side reaction with electrolyte and to improve the electrochemical properties by Li4Ti5O12 coating on LiNi0.8Co0.1Mn0.1O2 cathode material. Li4Ti5O12 has been reported as a kind of fast lithium-ion conductor because of its high mobility of lithium ions in the structure. In addition, it is also a zero-strain material, which means that there is no structural change during the insertion/extraction process of lithium-ion [3,4]. The Li4Ti5O12 coated cathode materials were characterized using SEM, TEM, XRD and electrochemical tests. Keyword: Li4Ti5O12 coating, Cathode materials Acknowledgement This study was supported by the granted financial resource from the Ministry of Trade program of the Industry & Energy, Republic of Korea (G02N03620000901). References [1] Hua Shi and Lianqi Zhang, J. Alloys and compounds 587 (2014) 710-716 [2] Z. Li, F. Du, X. Bie and D. Zhang, J. Phys. Chem. C 114 (2010) 22751 [3] S.J. Wen, G.J. Li, R.M. Ren, C.Y. Li, Mater. Lett. 148 (2015) 130–133 [4] Y. Liu, Q. Wang, Z. Zhang, A. Dou, J. Pan, M. Su, Advanced Powder Technology 27 (2016) 1481–1487

Authors : Williams Agyei Appiah1, Joonam Park2, SeoungWoo Byun1, Myung-Hyun Ryou2 and Yong Min Lee1*
Affiliations : (1) Department of Energy Systems Engineering, Daegu Gyeonbuk Institute of Science and Technology, 333 Techno Jungang Daero, Hyeonpung-Myeon, Dalseong-Gun, Daegu, Republic of Korea (2) Department of Chemical and Biological Engineering, Hanbat National University, 125 Dongseodaero, Yuseong-gu, Daejeon, 34158, Republic of Korea

Resume : A comprehensive mathematical model is developed to study the cycling performance of LiMn2O4/graphite lithium ion cells. The proposed model takes into consideration the formation and dissolution of the solid electrolyte interphase (SEI) at the anode, Mn(II) dissolution of LiMn2O4 cathode active material due to Mn(III) disproportionation reaction and its effects on the SEI at the anode as well as the formation of cathode electrolyte interphase (CEI) on the cathode. The decrease of Li ion diffusion coefficient in the cathode due to the formation of passive film and active material dissolution is added as a factor that results in capacity fade. Temperature effects on the capacity fade parameters and its kinetic reaction are incorporated in this model via an Arrhenius-type dependence of the rate constants and apparent diffusion coefficient. The developed model is incorporated into the Newman’s Porous Composite Electrode framework (PCE) and implemented in the battery module of COMSOL Multiphysics. The proposed model is used to study the effects of variations in temperature and voltage range of cycling on the capacity fade and changes in volume fraction of cathode active material, resistance in the cell and SEI thickness.

Authors : A. Boileau, F. Capon
Affiliations : Institut Jean Lamour, CP2S, UMR CNRS 7198, Ecole des Mines, Université Lorraine, Parc de Saurupt, 54042 Nancy, France

Resume : In this work, LaCoO3 thermochromic thin films were synthesised using DC reactive sputtering and subsequent annealing in air. The constitutive elements of the perovskite were deposited onto silicon and aluminium substrates at room temperature from two metallic targets (La and Co). The effect of the plasma composition was investigated using a pure argon atmosphere and an O2/Ar mixture. Thin films deposited in pure argon (La-Co) are crystallised in situ whereas films deposited in O2/Ar mixture (La-Co-O) are amorphous. In both cases, post-annealing treatments were carried out under ambient air to reach the perovskite structure. X-Ray Diffraction measurements have shown strong differences depending on the synthesis method. Infrared transmittance spectra of films deposited on silicon were recorded for temperatures ranging from 298 to 673 K by FTIR spectrometer. A thermochromic effect is observed at high temperature (between 473 and 573 K) and confirmed by electrical measurements performed by the four probes method. The emissivity of LaCoO3 films deposited onto aluminum was measured directly by thermal camera. The thicker LaCoO3 film deposited under argon shows an outstanding variation of its emissivity around 525 K. These results are very promising for the generation of new thermochromic films in the field of thermal control and thermally adaptive layers at high temperature.

Authors : V. Ruiz1, A. Kriston1, M. Destro2, D. Fontana2, E. Napolitano1, A. Pfrang1 E-mail of the corresponding author:
Affiliations : 1-European Commission, Joint Research Centre (JRC), Directorate for Energy, Transport and Climate, Energy Storage Unit, Westerduinweg 3, NL-1755 LE Petten, The Netherlands; 2-Lithops S.r.l, Strada del Portone 61, 10137 Torino, Italy

Resume : The degradation of commercial pouch cells (6Ah rated capacity) designed for subambient temperature operation is presented [1]. Electrochemical cycling was performed by constant current-constant voltage (CCCV) cycling at 1C between 2.7 V and 3.7 V. The effect of temperature on degradation processes is studied by utilizing dissimilar charging and discharging temperatures also supplemented by X-ray diffraction investigations. Design of Experiment and Analysis of Variance have been used. The effect of various conditions have on the LIBs is assessed by performing a reference cycle (described in IEC 62660-1꞉2011 [2]) at 25°C at the beginning of the test and after each set of 25 cycles. A significant quadratic relationship of degradation rate with charging temperature and a linear relationship with discharging temperature have been found. Furthermore an interaction between charging and discharging temperature was also revealed, which may imply the necessity to use simultaneous temperature cycling during the assessment of battery ageing during real life conditions. References [1] V. Ruiz, A. Kriston, I. Adanouj, M. Destro, D. Fontana, A. Pfrang, Electrochimica Acta, 240 (2017) 495-505. [2] IEC 62660-1: Rechargeable Cells Standards Publication Secondary lithium-ion cells for the propulsion of electric road vehicles. Part 1: Performance testing, (2011).

Authors : C. Mennucci,1 M.C. Giordano,1 C. Martella, 1 F. Buatier De Mongeot,1 P. M.H. Muhammad,2 M.F.O. Hameed,2 S.S.A. Obayya 2
Affiliations : 1 University of Genova, Department of Physics, Genova, 16146, Italy 2 Center for Photonics and Smart Materials, Zewail City of Science and Technology, Giza, Egypt

Resume : We propose engineered roughened substrate in view of light manipulation into optoelectronic devices. It is aimed to achieve light coupling across interfaces of dissimilar material employed in photonics devices exploiting one-dimensional pseudo-periodic gratings in view of broadband light scattering. We experimentally demonstrate large area (cm2) and high aspect-ratio nanopatterning of substrates by recurring to de-focused ion beam sputtering (IBS) through a self-organised sacrificial Au nanowire stencil mask. These nanoscale features, can be obtained on different substrates ranging from glass, transparent conductive oxides, metals and crystalline semiconductors like Si and GaAs. Textured substrates have been characterized from the morphological and optical point of view by means of an AFM microscope and an integrating sphere, respectively. Morphological parameters have been employed to simulate and analyze the optical response of textured glass by recurring to 3D finite difference time domain (FDTD) method. Pseudo periodic one-dimensional nanostructures endowed with high aspect ratio proved numerically and experimentally to be effective in view of broadband diffuse scattering of radiation. Haze values (around 30%) higher than commonly employed light trapping references are reported. Thin film solar cell based on the nanostructured pattern has been numerically studied for broadband absorption enhancement using the 3D FDTD. Tangible absorption enhancement is reported in nanostructured devices relative to the conventional flat thin film solar cell. The optimized SC can offer a short circuit current of 13.8 mA/cm2 with an enhancement of 21% over the SC without textured surface.

Authors : Taeyeong Han1, Williams Agyei Appiah2, and Myung-Hyun Ryou1**, Yong Min Lee2*
Affiliations : 1 Department of Chemical & Biological Engineering, Hanbat National University 125 Dongseo-daero, Yuseong-gu, Daejeon, 34158, Korea 2 Department of Energy Systems Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333, Techno Junang-daero, Hyeongpung-myeon, Dalseong-gun, Daegu, 42988, South Korea

Resume : Recently, electrochromic (EC) devices such as smart windows, sunroofs, car mirrors and sensors have been studied with energy saving and daylight control by color change. The EC materials have many candidates such as metal oxide, conducting polymer, and hybrid materials. Among them, NiO is an inorganic material known as an ion storage layer and anode EC material. However, NiO has low durability and low electrochemical reactions. Previous researchers have studied to increase this point by lithiation. Lithiation method is various such as dry lithiation, electrochemical lithiation, and direct contact lithiation. However, there is a lack of comparative study to the lithiation method. Herein, we try to compare most effective method of lithiation. First, we deposit NiO thin film by RF-sputtering method. Second, we make LixNiO by direct contact of Li metal and electrochemical method. And then, we experiment using beaker cells. Beaker cell consist of three electrode and electrolyte. The working electrode is NiO/ITO/glass, counter electrode is Pt electrode, reference electrode is Ag/AgCl (3M KCl), and electrolyte is 1M LiClO4 in PC. After, we evaluate LixNiO using Cyclic-voltammetry (CV) and measure transmittance by optical equipment. CV performed -1~1.5V voltage range and 20, 50, 100 mV/s scan rate, respectively. And, transmittance is measured from 440nm to 700nm visible range. Finally, We analyze the resistance of LixNiO using electrochemical impedance spectroscopy. Acknowledgements This work was supported by the *Energy Technology Program of the Korea Institute of Energy Technology Evaluation and Planning(KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20142010102980)

Authors : Seoungwoo Byun1, Joonam Park1, Williams Agyei Appiah1, Myung-Hyun Ryou2, Yong Min Lee1
Affiliations : 1 Department of Energy Systems Engineering Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333 Techno Jungang-daero, Heonpung-myeon, Dalseong-gun, Daegu, 42988, Republic of Korea; 2 Departement of Chemical and Biological Engineering, Hanbat National University, 125 Dognseo-daero, Yuseong-gu, Daejeon, 34158, Republic of Korea

Resume : Lithium-ion batteries (LIBs) extend the application area from IT equipment to transportation, while LIB shows the highest energy density with comparable output and reasonable cycle performance, but with temperature, humidity, vibration, temperature is not sufficiently evaluated in the case of a mild environmental condition. In particular, other than temperature, it is treated as a point of the main environmental variable. But considering that the humidity will vary greatly during the day, the reliability of the LIB It is not helpful to evaluate the effect of humidity on the humidity. This section identifies the effects of relative humidity on the self-discharge behavior of a fully charged LIB by monitoring the open-circuit voltage (OCV), capacity and power retention, and electrochemical impurities before and after storage. (Ni1 / 3Co1 / 3Mn1 / 3) O2 / graphite (NCM / graphite) chemistry and store it at high temperature and relative humidity (90% RH) at room temperature. As a result, the electrochemical characteristics such as capacitance, power retention rate, and cell impedance decrease, so that we can discuss the relation between self-discharge and humidity, and we can discuss the possible mechanism of this phenomenon We will try to propose one of them.

Authors : S. Saber1,2, M. Mollar1, A. M. El Nahrawy2, N. M. Khattab2, A. A. Eid2, M. M. Abo-Aly3, B. Marí1
Affiliations : 1 Institut de Disseny i Fabricació, Universitat Politècnica de València. Camí de Vera s/n 46022 València (SPAIN) 2National Research Center, 33El Bohouth St. (former El Tahrir St.)- Dokki - Giza - Cairo (EGYPT) 3Chemistry Department, Faculty of Science, Ain Shams University, Cairo (EGYPT)

Resume : In this work, copper indium gallium diselenide Cu(Inx,Ga1-x)Se2 (CIGS) nanoparticles were synthesized using a wet chemical solvothermal method. This method is based on a non-vacuum thermal process that does not use selenization. Introducing different metal sources in an autoclave with ethylenediamine as a solvent, CIGS nanoparticles were obtained at different temperatures range 180–230ᴏC. The effects of temperature, metal source, and growth conditions on the phase and particle size were investigated. X-ray diffraction results confirm the formation of a tetragonal CIGS structure as the main phase. Structures of the obtained phases were investigated using energy-dispersive X-ray spectroscopy (EDX). The morphology and size of the samples were determined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

Authors : Paulina Kamińska, Piotr Śpiewak, Wojciech Święszkowski
Affiliations : Faculty of Materials Science and Engineering, Warsaw University of Technology, Wołoska 141, 02-507 Warsaw, Poland

Resume : Bismuth telluride is of a great interest today due to the potential for improving its thermoelectric properties near room temperature by doping effect. Experimental results show that thermoelectric properties can be considerably enhanced by doping with rare earth elements (RE), such as Ce, Y, Er or Yb. However, the electronic structure of RE-doped Bi2Te3 have not been reported yet and the relations between its electronic band structure and thermoelectric properties are still unknown. Therefore, in this work we employed the density functional theory (DFT) to investigate the electronic properties of 2.5at. % RE doped Bi2Te3. The DFT calculations were based on the semilocal general gradient approximation (GGA) in the parametrization of Perdew-Burke-Ernzerhof (PBE) for the exchange-correlation potential. Transport properties of electrons were provided using Boltzmann’s transport theory. It is found that the accurate description of the electronic band structure of bismuth telluride strongly requires incorporation of spin-orbit coupling (SOC) in calculations. Without the SOC, both the conduction and the valance edges are located at Γ point, whereas band gap becomes indirect with the SOC included which is in agreement with experimental data. Analysis concerning the effect of 4f-electrons in RE elements on density of states as well as electronic and thermoelectric properties in the considered materials shows to be beneficial for developing novel thermoelectric materials.

Authors : Min-Sik Park a, Jeom-Soo Kim b, Jong-Won Lee c
Affiliations : a Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin 17104, Republic of Korea; b Department of Chemical Engineering, Dong-A University, 37 Nakdong-daero, Saha-gu, Busan 49315, Republic of Korea; c New and Renewable Energy Research Division, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 34129, Republic of Korea.

Resume : Perovskite-type Li3xLa(2/3)?x?(1/3)-2xTiO3 (LLTO) is regarded as a promising inorganic solid electrolyte for use in all solid-state batteries. However, the practical use of LLTO is limited by its large domain boundary resistance, leading to the low total conductivity. In order to reduce the large domain boundary resistance, a correlation between the microstructures and Li+ conducting properties of LLTO is thoroughly investigated. In practice, we found that the sintering temperature and Li concentration are predominant factors for determining the microstructures of LLTO and affecting the domain boundary resistance. By controlling the synthesis parameters, LLTO shows a total Li+ conductivity as high as 4.8 × 10?4 S cm?1 at room temperature. It would be helpful to understand Li+ conducting behaviors of LLTO and make a further progress in this research field.

Authors : Hyunmi Doh, Subin Choi, Hyun S. Park, Suk Woo Nam, and Chang Won Yoon*
Affiliations : Fuel Cell Research Center, Korea Institute of Science and Technology, Hwarangno 14gil 5, Seongbukgu, Seoul 02792, Republic of Korea

Resume : Hydrogen is the cleanest and sustainable energy carrier, and has attracted significant attention. However, widely applicable hydrogen-based energy technologies including hydrogen production, storage and utilization still remain a lot of challenges. Among these, economically viable hydrogen storage is particularly needed to achieve hydrogen economy. To address this issue, a number of potential hydrogen storage materials are proposed. Particularly, materials that use liquid chemicals have advantages on high volumetric energy storage densities with safe and economical transportation. One of such promising chemicals is formic acid (FA), which can be easily transported into a desired site and release H2 even at ambient condition. However, H2 release via FA decomposition (HCOOH→H2+CO2) can also produce an undesired byproduct, carbon monoxide through dehydration (HCOOH→H2O+CO) which is detrimental to fuel cell applications. It is thus necessary to develop highly selective and active catalysts. We present here the preparation, characterization, and H2–release properties of novel metal composite catalysts and their catalytic activities toward FA dehydrogenation.

Authors : Kovendhan Manavalan, Eunji Han, Ki-Joon Jeon*
Affiliations : Department of Environmental Engineering, Inha University, Incheon 402-751, South Korea.

Resume : Molybdenum disulfide (MoS2), a transition metal dichalcogenide has attracted a lot of attention because of its unique spin orbit coupling, electronic, and photonic applications. Moreover, it is widely reported as a promising HER electrocatalyst. Graphene, a two-dimensional carbon allotrope, has been considered as a promising coating material for many of applications in energy storage and production. Hardly there are few reports are available on the growth of graphene directly on stainless steel substrates. In this work, we have grown graphene directly onto the stainless steel (SS304) substrate via atmospheric pressure chemical vapor deposition (APCVD) and MoS2 was deposited over this graphene layer by a low pressure chemical vapor deposition. From Raman spectra after 100 CV cycles in 1 M KOH, 0.5 H2SO4, 3.5% NaCl the three most intense features at 1351, 1576 and 2697 cm−1 confirms that the directly grown samples have good corrosion resistance and stability. In addition to that we observe the characteristic MoS2 peaks E12g (374 cm-1) and A1g (402 cm-1) assigned to the stretching vibration of MoS2. The current density is 15 times higher for MoS2 when compared to stainless steel. Also for MoS2 the EIS decreases 1.5 times when compared to uncoated one. This confirms that the directly grown graphene is highly stable after 100 CV cycles and good HER activity was achieved. These results will be presented and discussed.

Authors : Mariusz Drygaś (1), Katarzyna Kapusta (1), Jerzy F. Janik (1), Piotr Jeleń (2), Maciej Sitarz (2)
Affiliations : AGH University of Science and Technology, (1) Faculty of Energy and Fuels, (2) Faculty of Materials Science and Ceramics; Al. Mickiewicza 30, 30-059 Krakow, Poland

Resume : Kesterite-type compounds, e.g., Cu2ZnSnS4 (CZTS), are the most promising materials for low cost, highly efficient, and environmental-friendly solar cells. Due to the complex structure and frequent nonstoichiometry/defects, the CZTS materials are still subject to many structural investigations. In this study, we report the powder XRD, solid-state 65Cu, 119Sn MAS NMR, and micro-Raman determinations for kesterite powders obtained via mechanochemical synthesis. The substrate elements in the stoichiometric ratio of the metals and a slight excess of sulfur were ground in a high-energy ball mill at 900 rpm and grinding times from 1 to 10 h and, subsequently, were pyrolyzed under an argon flow at temperatures of 450-550 ºC. Based on the analytical data, the raw materials after milling were nanopowders showing the sphalerite-type crystallographic characteristics with a highly disordered Sn/Cu sublattice. The additional pyrolysis at an elevated temperature resulted in the ordered structure of almost pure kesterite. In certain cases, some apparently unreacted elemental tin was found to undergo oxidation upon exposure to air to yield a tin dioxide by-product. The milling time and the temperature of pyrolysis were the key factors in the evolution of short range ordering in the investigated CZTS materials.

Authors : Jong Hwa Lee1, Young Yun Kim1 2, O. Ok Park1*
Affiliations : 1 Department of Chemical and Biomolecular Engineering (BK21 graduate Program), Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea 2 Division of Advanced Materials, Korea Research Institute of Chemical Technology, 141 Gajeong-ro, Yuseong-gu, Daejeon 34114, Republic of Korea

Resume : Stamping transfer process for fabricating organic electronics has recently been demonstrated to improve device performance because it allows the control of morphology, patterning, and transfer of various materials. In this research, organic flexible solar cells with enhanced cell performance and mechanical durability were fabricated by performing a simple dry transfer of a poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) hole transport layer. In order to ensure more stable flexibility of flexible solar cell, we introduced the polystyrene nanoparticles (PS NPs) which can be served as binders and interfacial modifiers in the PEDOT:PSS layer. The transfer of the PEDOT:PSS layer with PS NPs was also performed completely via stamping transfer with polyurethane acrylate stamp. The power conversion efficiency of PTB7:PC71BM based on flexible device prepared by the dry transfer of PEDOT:PSS with PS NPs was 5.71%, which was significantly higher than that of the spin-cast device (5.37%). Enhanced performance was attributed to tuned work function and surface morphology of the PEDOT:PSS layer by controlling the position of PSS enrichment in the PEDOT: PSS layer using the dry transfer. Especially, we have found remarkable improvement on mechanical stability of flexible device with PS NPs. The introduced PS NPs allowed the flexible device to tolerate higher mechanical deformations by enhancing the mechanical toughness of the PEDOT:PSS due to their elastic properties.

Authors : N. Patelli, M. Calizzi, G. Rossi, F. Boscherini, L. Pasquini
Affiliations : Department of Physics and Astronomy, University of Bologna, 40127 Bologna, Italy

Resume : Materials for energy conversion and storage need to combine several functionalities, such as light absorption, electronic and ionic transport, mass transport, catalytic efficiency and selectivity. The development of novel synthesis techniques represents a key ingredient towards a successful exploitation of new materials with performances beyond the state-of-the-art. Here we present two energy-related applications of the gas phase condensation (GPC) technique [1,2]. GPC is a bottom-up physical synthesis method, in which nanoparticles (NPs) are formed by condensation of supersaturated atomic vapors in a gas atmosphere. By using multiple vapor sources, alloy precursors, and reactive gases, one can obtain pure metals, alloys, oxides and hydrides NPs as well as nanocomposites. The first example is given by MgH2-TiH2 composite NPs grown by co-evaporation of Mg and Ti under a He/H2 atmosphere. The coexistence of two phases at the single NP level results in outstanding hydrogen sorption properties [1] and may lead to other applications such as conversion anodes in Li-ion batteries. The second application deals with V-doped TiO2 NPs obtained through evaporation of a Ti-V alloy in a He/O2 atmosphere. V-doping enhances optical absorption compared to pure TiO2. X-ray absorption spectroscopy shows that V occupies a substitutional cationic site in both rutile and anatase polymorphs [2]. [1] N. Patelli et al, JPCC 121, 11166 (2017) [2] G. Rossi et al, JPCC 120, 7457 (2016)

Authors : Adnan Tasdemir1, Emre Bicer2, Alp Yurum2, Selmiye Alkan Gursel 1 and 2
Affiliations : 1 Sabanci University Faculty of Engineering & Natural Sciences, Tuzla, 34956, Istanbul, TURKEY; 2 Sabanci University Nanotechnology Research and Application Center (SUNUM), Tuzla, 34956, Istanbul, TURKEY

Resume : Cerium dioxide (CeO2) is one of the most studied rare earth wide bandgap semiconductor as a catalyst material. Ceria can be synthesized with several different morphologies such as nanocubes, nanotubes, nanorods, nanowires, microplates and octahedrons. The oxygen vacancies tend to be mostly abundant in nanorod form and, with its active facets, it leads to the improvement of highly efficient catalytic properties without changing the catalyst composition. In addition, ceria can be doped with mono-, di-, and trivalent elements to create oxygen vacancies within its structure in order to increase its catalytic performance. In this study, nitrogen-doped reduced graphene oxide (NrGO) was synthesized by a thermal annealing of GO at elevated temperatures. Then, Cu and Mn-doped CeO2 nanorods were successfully synthesized by a simple hydrothermal process. Lastly, NrGO supported Cu and Mn-doped CeO2 nanorods were obtained after another hydrothermal process. The structural and morphological analyses of Mn and Cu-doped ceria nanorods were performed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and RAMAN spectroscopy. The temperature programmed reduction (TPR) experiments were performed on these catalysts in a fixed-bed quartz reactor to characterize carbon monoxide oxidation. The results revealed that the extent of carbon monoxide oxidation was proportional to the amount of doping. The NrGO supported ceria catalysts had been found to be very active due to the well-dispersed nanostructures.

Authors : F. Bouhjar (a,b,c) , M. Mollar (a), B. Marí (a)  and B. Bessaïs (b)
Affiliations : (a) Institut de Disseny i Fabricació, Universitat Politècnica de València. Camí de Vera s/n 46022 València (Spain) (b) Laboratoire Photovoltaïques, Centre de Recherches et des Technologies de l’Energie Technopole  H.lif 2050 (Tunisia) (c) University of Tunis (Tunisia)

Resume : Polycrystalline Cr-doped hematite thin films have been successfully deposited on fluorine-doped tin oxide coated (FTO) glass substrates using the facile hydrothermal method. The hydrothermal bath consists of an aqueous solution containing a mixture of FeCl3.6H2O and NaNO3 adjusted to a pH = 1.5. The samples were introduced in an autoclave and heated for a fixed duration and temperature. Afterward, the hematite coated samples were annealed for a 4 h at 550°C. The Cr doping fractions were varied from 2 to 20 %. All samples were submitted to structural and morphological studies using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and High-resolution transmission electron microscopy (HRTEM). Cr doping induces a slight shift of the main diffraction peaks (012) and (104) towards lower angles. On the other hand, chronoamperometry technique showed that Cr-doped films exhibited higher photoelectrochemical activity relatively to un-doped α-Fe2O3 thin films. Maximum photocurrent densities as well as incident photon conversion efficiencies (IPCE) have been obtained for 16% Cr-doped films in a normal alcaline solution and under standard illumination conditions. We attributed this high photoactivity to the high active surface area of the nanostructured hematite and to the increasing donor density caused by Cr doping.

Authors : Wolfram Münchgesanga, Anastasia Vyalikha, Dirk C. Meyer
Affiliations : Technische Universität Bergakademie Freiberg - Institut für Experimentelle Physik - Leipziger Straße 23 - 09596 Freiberg - Germany

Resume : The mixed-layer structure of Rectorite (Rt), made up of alternating nonexpandable (mica) and expandable (smectite) layers in a 1:1 ratio, can be used to transport and intercalate mobile ions like Na+, Li+ and Mg+ in an aqueous media. Therefore Rt isin principle suitable as intercalation cathode/anode in batteries. Starting from a crystallographic point of view, the changes of the complex conductivity of Rt with different by hydration replaced mobile species are discussed and correlated to structural and chemical data from NMR and XPS measurements. This work was financed by der Federal Ministry of Education and Research within the project SyNeSteSia (05K2014) and CERIC grand N20162054 (EU).

Authors : Yujin Han, Hyunmyoung Oh, Dasom Jeon, Cheolmin Lee, Jungki Ryu
Affiliations : Department of Energy Engineering, School of Energy and Chemical Engineering Ulsan National Institute of Science and Technology (UNIST)

Resume : Electrochemical or photoelectrochemical water splitting enables eco-friendly production of fuels and thus has drawn enormous attentions across the world. For its practical application, however, water oxidation catalysts (WOCs) should be employed to facilitate the four-electron water oxidation reaction, which is the rate-determining step. Conventionally, ruthenium and iridium oxide has attracted great interests because of their high catalytic activity and stability. Nevertheless, these transition metals are not only costly and but also unsustainable . Here, we report a novel method to synthesize an efficient and stable CoWO4-based-WOC from cobalt-based polyoxometalates, [Co4(H2O)2(PW9O34)2]10- (Co4POM). Simple annealing process leads to conversion of Co4POM to CoWO4-based-WOC with an enhanced catalytic activity for water oxidation. It was found that a phase transition from amorphous to crystalline CoWO4 (c-CoWO4) occurs between 400°C and 500°C and that amorphous CoWO4 (a- CoWO4) exhibited a higher catalytic activity than c-CoWO4. Based on these results, we deposited CoWO4-based-WOCs on hematite by layer-by-layer assembly of Co4POM and subsequent heat treatment to fabricate an efficient hematite-based photoanode for solar water oxidation. We found that the photoelectrochemical performance of the hematite photoanode was significantly improved after the decoration with a-CoWO4 WOC in terms of photocurrent density and onset potential. We believe that out findings can suggest simple way to synthesize efficient and stable WOCs and to deposit them on photoelectrode for enhanced water oxidation reaction.

Start atSubject View AllNum.Add
Authors : Soo Young Kim, Quyet Van Le
Affiliations : School of Chemical Engineering and Materials Science, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 06974, Republic of Korea

Resume : In recent years, the unprecedented development of a new class of electronic materials, called organo/inorgano lead halide perovskites, has occurred. These have the chemical formula ABX3 (A = methyl ammonium, formamidium, or cesium; B = Pb or Sn; X = halide: I, Br, Cl, or a mixture such as BrxI3−x); materials based on them exhibit excellent optical, electrical, and chemical properties such as a high absorption coefficient, low exciton binding energy, tunable band gap, high charge-carrier mobility, long charge-carrier diffusion length, and low-temperature solution processability. Solar cells with perovskite as the active material have exhibited a power conversion efficiency (PCE) exceeding 20%, making them a very promising candidate to replace expensive silicon solar cells in the near future. Moreover, perovskite materials have also showed their potential in a variety of electronic applications such as memristors, photodetectors, field effect transistors, and light emitting diodes (LEDs). Perovskite LEDs have attracted considerable interest because of their extremely high performance in terms of maximum luminance, current efficiency, and internal quantum efficiency, which are comparable to those of organic LEDs. In this study, Inorganic CsPbX3 perovskites with compositions including CsPbBrxCl3–x, CsPbBr3, and CsPbBrxI3–x were synthesized, and their properties were investigated. Tauc plots calculated from the UV-vis spectra of the materials showed that the band gaps of CsPbBrxCl3–x, CsPbBr3, and CsPbBrxI3–x were 2.7, 2.35, and 1.8 eV, respectively. The as-prepared CsPbX3 nanocrystals (NCs) had a cubic structure and their crystal sizes were around 5–10 nm. The diffraction peak intensity of the (110) plane increased by adding Cl anion and reduced by adding I anion. In contrast, the peak intensity of the (200) plane reduced by the introduction of Cl– ions and increased by the introduction of I– ions, suggesting that the nature of the halide anions affects the crystal orientation of CsPbX3 quantum dots. The highest occupied molecular orbital/lowest unoccupied molecular orbital levels of CsPbBrxCl3–x, CsPbBr3, and CsPbBrxI3–x calculated from ultraviolet photoemission spectra and UV-vis spectra, were 6.5/3.8, 6.5/4.15, and 6.1/4.3 eV, respectively. The maximum luminance values measured for CsPbBrxCl3–x, CsPbBr3, and CsPbBrxI3–x -based LEDs were 15.2, 51.7 and 21.7 cd/m2, respectively. Furthermore, we present a study of the synthesis-temperature dependence of CsPbX3 perovskite for NCs, using X-ray scattering. To this end, we synthesized CsPbX3 perovskite NCs at different reaction temperatures in the form of colloids and spin-coated films, and performed small-angle and wide-angle X-ray scattering measurements to characterize the sizes and crystal structures of the NCs and their assembled structures. The synthesis temperature is that of the reaction between Cs-oleate and PbX2 (X: I, Br, or Cl), and it is the reaction temperature rather than the reaction duration that determines the size of the CsPbX3 NCs. We also investigated the dependence on the synthesis temperature of the performance of quantum dot LED devices fabricated with these NCs. It is expected that this research provides an overview of the energy levels and crystal structures of CsPbX3 quantum dots for the design of inorganic perovskite-based LEDs with high luminance and power efficiencies. Acknowledgement This research was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP) (No. 2014R1A2A1A11051098; 2015K1A3A1A59073839).

Authors : Shigeto Okada1, Kosuke Nakamoto2, Ryo Sakamoto2, Masato Ito1, Ayuko Kitajou1
Affiliations : 1 Institute for Materials Chemistry and Engineering, Kyushu University
, Kasuga, Japan 2 Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Japan

Resume : Na-ion battery with aqueous electrolyte that are safe, cost effective, and offer high ionic conductivity have been proposed as attractive alternatives for large-scale energy storage. The last but not least problem associated with aqueous electrolytes is the low operating voltage restricted by the electrochemical window of water.
In this study, in order to confirm the high-concentration effect in NaClO4 aq. electrolyte, we have selected sodium manganese hexacyanoferrate (NMHCF) as a cathode and NTP as an anode, respectively. In addition, we investigated the operation and deterioration mechanism of the full cell by tracing pH and electrode elution during cycling. NaxMn[Fe(CN)6]y·zH2O (0 ≤ x ≤ 2, 0 ≤ y ≤ 1, 0 ≤ z, NMHCF) cathode active materials were obtained by co-precipitating method. NaTi2(PO4)3 (NTP) anode active material was prepared by using conventional solid-state method from stoichiometric starting materials. Cathode and anode pellets were fabricated by 70 wt % of NMHCF or NTP with 25 wt% AB and 5 wt % PTFE binder and punched into disks. The cathode/anode weight balance for this ion-type cell is 2:3, and the cathode/anode capacity balance is approximately 2:3 (excess capacity of NaTi2(PO4)3). To check the concentration effect, several kinds of aqueous electrolytes with various NaClO4 concentration between 1 mol/kg and 17 mol/kg were used. As a result, the highly concentrated aqueous electrolyte showed the larger charge/discharge overpotential than the diluted aqueous electrolyte and it was useful to improve the rechargeable capacity and the discharge voltage without the electrolyte decomposition.

Authors : Anji Reddy Munnangi
Affiliations : Helmholtz Institute Ulm (HIU), Helmholtzstr. 11, 89081 Ulm, Germany

Resume : Sodium-ion batteries (NIB) are evolving as a low-cost alternative to the state-of-the-art lithium-ion batteries (LIB). Elementary properties of sodium, high abundance and low cost associated with sodium precursors made it a realistic alternative to lithium-ion chemistry [1, 2]. Research activities on NIB are growing worldwide and still require a great deal of basic research. Here, we present the synthesis and electrochemical properties of sodium vanadium oxy phosphate, Na2+xV3P2O13 (0 ≤ x ≤ 1). The crystal structure of Na2+xV3P2O13 (0 ≤ x ≤ 1) was identified by Rietveld refinement of the powder X-ray diffraction pattern. It shows a reversible capacity of 150 mAh g-1 at an average voltage of 2.5 V vs. Na/Na+. The post-structural analysis shows Na2+xV3P2O13 (0 ≤ x ≤ 1) is structurally stable over a wide range of sodium extraction and reinsertion demonstrating its potential as cathode material for NIB. On the anode side, we are developing hard carbon derived from biomass. The electrochemical performance of hard carbon was investigated in three different electrolytes. The nature of solid electrolyte interface (SEI) formed was investigated in greater detail by using XPS analysis. FEC containing electrolytes formed favorable SEI and improved the cycling stability of hard carbon. Furthermore, sodium insertion and deinsertion in hard carbon was investigated by in-situ Raman spectroscopy. References: 1. M. D. Slater, D. Kim, E. Lee, C. S. Johnson, Adv. Funct. Mater. 2013, 23, 947. 2. N. Yabuuchi, K. Kubota, M. Dahbi, S. Komaba, Chem. Rev. 2014, 114, 11636.

Authors : Raphaël JANOT
Affiliations : Laboratoire de Réactivité et Chimie des Solides, UMR 7314 CNRS, Université de Picardie Jules Verne, 80039 Amiens, FRANCE

Resume : Mesoporous carbons are used for the nano-confinement of both electrode materials of Li-ion batteries and hydrogen storage materials. The use of these host matrices allows a perfect control of the particles size at the nanoscale and a close embedding within a conductive carbon matrix. This approach leads to fast kinetics and can stabilize unusual polymorphs. This will be especially illustrated in the case of Li3N for hydrogen storage and Li2FeSiO4 for positive electrode of Li-ion batteries.

10:30 Coffee break    
Authors : Eva Majkova, R. Subair, P. Siffalovic, V. Nadazdy, T. Shabelnyik, Y. Halahovets, M. Jergel, J. Kulicek*, M. Micusik*, M. Omastova*
Affiliations : Institute of Physics SAS, SK 845 11 Bratislava, Slovakia *Polymer Institute SAS, SK 845 41 Bratislava, Slovakia

Resume : Organometallic perovskite solar cells (PSCs) are one of the hot research topics in the 3rd generation photovoltaics due to their power conversion efficiency (PCE) exceeding 20%. Recent results confirm an important role of the crystallinity and morphology of organometallic perovskite structure on the electrical properties and stability of PSCs. In this work we present time-resolved studies of the structure of organometallic CH3NH3PbI3 xClx layer exposed to various annealing temperatures by in-situ grazing-incidence wide-angle X-ray scattering. Simultaneously, a series of identical layers annealed up to different stages of structure evolution was measured ex-situ by energy-resolved electrochemical impedance spectroscopy developed by us to map DOS in the band gap of the perovskite layer. In this way, correlation between the details of the perovskite crystal structure and the electronic structure in terms of the defect states in the band gap could be observed and its effect on the performance of PSCs could be studied. A significantly higher density of defect states in the band gap (more than two orders of magnitude) was found for the perovskite layer deposited onto inherently rough glass/ITO substrate comparing to smooth Si one. An optimized annealing temperature providing the best solar cell parameters exhibited also the lowest density of defect states. Moreover, a possibility of application of a conductive polymer composite electrode layer as PSC top electrode was investigated.

Authors : Marketa Zukalova1, Barbora Pitna Laskova1, Ladislav Kavan1, Mariana Klementova2
Affiliations : 1J. Heyrovský Institute of Physical Chemistry, v.v.i., AS CR, Dolej?kova 3, CZ-18223 Prague 8, Czech Republic; 2Institute of Physics of the AS CR, v.v.i., Na Slovance 2, 182 21 Prague, Czech Republic

Resume : Li4Ti5O12 spinel (LTO) and Na2Ti3O7 have been recently studied as promising anode materials for Na-ion batteries. Na insertion in Li4Ti5O12 is accompanied with development of extra phase with an about 4-5% larger unit cell volume which co-exists with LTO in a single particle and is identified as a Na-substituted LTO phase. In our work Na insertion into sol-gel made LTO and reference commercial spinel were studied by cyclic voltammetry and chronopotentiometry. Nanocrystalline LTO exhibited the best performance for Na storage, with charge capacity twice as high as those of reference Aldrich LTO (156 mAhg-1). A capacity drop of nano LTO during galvanostatic cycling was ascribed to irreversible structural changes induced by Na accommodation in the Li4Ti5O12 lattice. Raman spectroscopy of nano LTO after Na insertion revealed a formation of orthorhombic Li0,5TiO2 phase in originally phase pure Li4Ti5O12. The occurrence of this phase, commonly formed during Li insertion into anatase, is discussed in terms of induced Li redistribution and its accommodation in very minor anatase impurities detectable by Raman spectroelectrochemistry and HRTEM, but visible neither by X-ray diffractometry nor cyclic voltammetry of Na insertion. Na2Ti3O7 works as an effective low-voltage insertion Na compound being able to reversibly uptake 2 Na ions per formula unit (200 mAh/g) at an average potential of 0.3 V. We correlated an electrochemical performance of Na2Ti3O7 during Na insertion in with its particle size (surface area). Acknowledgement: This work was supported by the Grant Agency of the Czech Republic (contract No. 15-06511S) and by the Czech Ministry of Education, Youth and Sports (contract No. 8F15003).

Authors : Mariko Matsunaga
Affiliations : Chuo University

Resume : Recently, various carbon electrodes and their composites have been investigated for electrochemical energy devices, such as lithium ion batteries, fuel cells, capacitors, dye-sensitized solar cells. Among them, nano-carbons are often used as components because of their good electrochemical activity, chemical stability, and strong mechanical strength. In our recent studies, several morphological types of nano-carbons are electrophoretically deposited on the substrates, and then these carbons are electrochemically modified depending on the application. Thus, almost all the process was carried out in a beaker using electric power as small as possible to prepare electrodes with simple handling, relatively low cost, and less time in comparison with the conventional methods such as chemical vapor depositions, electrostatic spray. The presentation includes the results on the effects of several deposition conditions of the nano-carbons on the electrode performance, and some application examples of the prepared films.

Authors : Daniele Pontiroli, Giacomo Magnani, Silvio Scaravonati, Mattia Gaboardi, James C. Pramudita, Neeraj Sharma, Chiara Milanese, Giovanni Bertoni, Mauro Riccò
Affiliations : Carbon Nanostructures Laboratory, Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università degli Studi di Parma, Parma, Italy; Rutherford Appleton Laboratory, ISIS Facility, Didcot, UK; Dalton Building, University of New South Wales, Sydney, Australia; Dipartimento di Chimica, Università di Pavia, Pavia, Italy; IMEM-CNR, Parma, Italy

Resume : Rechargeable Li-ion batteries (LIBs) represent the state-of-the-art for the power supply in technological devices, but the wide-scale implementation of this technology, for example in the automotive field, would raise issues concerning the limited lithium mineral reserves. Investigation of alternatives to lithium is hence highly desirable, although it requires the identification of new materials suitable as components for new batteries, possibly displaying even better performance of the current commercial systems. In this framework, graphene-based materials can be good candidates. Chemical graphene is suitable for the development of high-capacity LIBs, in virtue of its high porosity, electronic and mechanical properties. Recently, we found that anodes based on graphene derivatives can also support the insertion of Na+ ions with high capacity and stability upon cycling. In particular, thermally exfoliated graphene oxide (TEGO) produces capacities of 248 mAh/g after 50 cycles, H-treated TEGO shows reversible capacity of 491 mAh/g after 20 cycles, while Ni-nanoparticles decorated TEGO displays up to 420 mAh/g reversible capacity after 25 cycles with 97% coulombic efficiency. Solid-state 23Na NMR performed on different chemically synthesized graphene materials allowed to shed light on the mechanism of sodium insertion/extraction on the defective graphene surfaces. These findings indicate the feasibility of the development of novel graphene-based Na-ion batteries (SIBs).

Authors : Nicholas M. Musyoka*, Khavharendwe M. Rambau*, Lerato Y. Molefe*, Magdalena Wdowin**, Wojciech Franus***
Affiliations : *HySA Infrastructure Centre of Competence, Materials Science and Manufacturing, Council for Scientific and Industrial Research (CSIR), Pretoria, South Africa; **Mineral and Energy Economy Research Institute, Polish Academy of Sciences, Wybickiego 7A, 31-261 Krakow, Poland; ***Department of Geotechnical Engineering, Faculty of Civil Engineering and Architecture, Lublin University of Technology, Nadbystrzycka 40, 20-618 Lublin, Poland.

Resume : Activated carbons have desirable traits for many energy related applications such as in Li-ion batteries, supercapacitors and hydrogens storage, among others. In order to improve their properties, there is always a need for increasing their surface areas and porosity. In this case, activation parameters such as the type of carbon precursor, method of activation and activation time play an important role in determining the properties of the resulting activated carbons. In this study, a newly reported mechanochemical/compactivation strategy was adopted for activating carbons stripped from coal fly ash. The compactivation approach involves the compressions of the carbon precursor and activation agent into a pellet at a certain pressure and time prior to activation. The process reduces the interparticle void between the precursor and activating agent thus creating more reactive sites for activation. This approach has previously been used on sawdust and zeolite templated carbon precursors and not yet tried on carbon concentrates from coal-combustion fly ash. Two carbon concentrates were obtained by demineralising carbon-rich coal fly ash samples sourced from Poland and South Africa and utilised as the activating carbon precursors. The obtained results showed that the resulting mechanochemically activated carbons had a >20% increase in surface area compared to the conventionally activated carbon. The samples were also found to show negligible changes in their pore size distribution and possessed improved hydrogen storage capacities.

13:00 Lunch break    
Authors : Seokwoo Jeon
Affiliations : Department of Materials Science and Engineering, KAIST Advanced Battery Center, KINC, KAIST 291 Daehak-ro, Yuseong Gu, Daejeon 305-701, Korea

Resume : The realization of high resolution, large area nanopatterning has been demonstrated from numerous methods. Above all, Proximity field nanoPatterning (PnP) is a unique three dimensional (3D) patterning methods using optical interference from conformal phase masks that contact directly on top of the surface of photosensitive materials. The contact allows incomparable stability in the size of pattering area, resolution, and reproducibility. Applying these large area, 3D nanostructures to thermoelectric applications could be very beneficial for tailoring σ, S, and κ to enhance the thermoelectric performance beyond intrinsic limit, however, which is difficult due to the coupling among the physical parameters. Major motivation to apply nanostructures for thermoelectric material is the selective suppression of κ arising from extrinsic phonon scattering at nanostructured interfaces without changing the electrical transport. Here we present the first demonstration of 3D thermoelectric materials by infiltrating polymeric 3D nanostructures with various materials such as poor thermoelectric zinc oxide or BiSbTe. The 3D nanostructures makes the poor thermoelectric oxide possess 100 times better zT and successfully reduces the κ from 1.14 to 0.87 W/mK at 350 K with maintaining the σ of 64,450 S/m and the S of -144 μV/K. Consequently, the 3D nanostructured Bi1.5Sb0.5Te3 film shows the highest ZT of 0.57 which is approximately 50% higher than the ordinary Bi1.5Sb0.5Te3 film. Further research of optimized material would make this strategy useful for advanced thermoelectric devices.

Authors : Craig A. J. Fisher,1) Akihide Kuwabara,1) Shunsuke Kobayashi,1) Yumi H. Ikuhara,1) Yoshio Ukyo,2) Yuichi Ikuhara1,3)
Affiliations : 1) Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan; 2) Office of Society-Academia Collaboration for Innovation, Kyoto University, Uji, Kyoto 611-0011, Japan; 3) Institute of Engineering Innovation, The University of Tokyo, Bunkyo, Tokyo 113-8656, Japan

Resume : Development of the next generation of lithium-ion battery materials requires a detailed understanding of the atomic-level structures and properties not just of bulk crystals but also of low-symmetry features such as surfaces, grain boundaries and, particularly in the case of solid-state batteries, heterogeneous interfaces between electrodes and electrolyte [1]. Such features can display very different ion migration energetics, structural stabilities, and electronic conductivities. The combination of atomic-level computer simulation with atomic-resolution scanning transmission electron microscopy provides a powerful means of probing such features, as a number of recent papers have demonstrated [e.g., 2,3]. In this paper, examples of computer modeling of surfaces and other two-dimensional features of lithium-ion battery cathode materials LiMPO4 (M = Mn, Fe, Co, Ni) and LiCoO2 will be presented and compared with structures observed using state-of-the-art scanning transmission electron microscopes. The observed features will be related to their performance as cathode materials, particularly in terms of cycle life and capacity fade. [1] M. S. Islam and C. A. J. Fisher, Chem. Soc. Rev., 43 (2014) 185-204. [2] S. Kobayashi, C. A. J. Fisher, T. Kato, Y. Ukyo, T. Hirayama and Y. Ikuhara, Nano Lett., 16 (2016) 5409–5414. [3] Y. H. Ikuhara, X. Gao, C. A. J. Fisher, A. Kuwabara, H. Moriwake, K. Kohama and Y. Ikuhara, J. Mater. Chem. A, 5 (2017) 9329-9338. Acknowledgment: This work was supported by the Research & Development Initiative for Scientific Innovation of New Generation Batteries II (RISING II) project of NEDO, Japan.

Authors : Manickam Minakshi
Affiliations : School of Engineering and Information Technology, Murdoch University, WA 6150, Australia

Resume : Sustainable energy sources require efficient energy storage system with increased power and energy densities. Integrating energy storage devices such as rechargeable battery and supercapacitors will have an effective utilization of varying renewable energy resources. To enable the renewable integration into a large-scale deployment, the amount of storage depends on the chosen electrode material, and its electrochemical activity. Therefore, the race for better electrochemical energy storage systems has prompted to examine the stability in the molybdate framework (MMoO4; M = Mn, Co or Ni) through selecting the appropriate transition metal cations from both computational and experimental approaches. Comparing to oxides and phosphate frameworks, molybdates (MMoO4) have demonstrated improved electrochemical properties [1-2]. Molybdate materials synthesized with controlled nanoscale morphologies have been utilised as a cathode in energy storage systems. The computational and experimental data confirms that the MnMoO4 crystallised in β form with α-MnMoO4 type whereas Co and Ni cations crystallised in α form with α-CoMoO4 type structure. Among the transition metal cations (Mn, Co or Ni) studied in the molybdate, hybrid capacitor comprising NiMoO4 vs. activated carbon exhibited excellent electrochemical performance having the specific capacitance 82 F g-1 at a current density of 0.1 A g-1 but the cycling stability need to be significantly improved. The specific capacitance of the NiMoO4 electrode material is shown to be directly related to the surface area of the electrode / electrolyte interface but the CoMoO4 and MnMoO4 favoured a bulk formation that could be suitable for structural stability. However, the capacitors comprising CoMoO4 and MnMoO4 showed an initial capacitance of 40 F g-1 and 20 F g-1 at a current density of 0.1 A g-1. Therefore, a better understanding of possible crystal configurations and the development of ternary metal molybdate can lead to efficient energy storage system. The experimental findings are correlated well through density functional theory based electronic structure calculations. Overall, both the theoretical and experimental insights of synthesized transition metal molybdates suitable for hybrid capacitors will be presented at the meeting. References 1. M. Minakshi, M. J. Barmi, and R. T. Jones, Dalton. Trans. 46 (2017) 3588. 2. T. Watcharatharapong, M. Minakshi Sundaram, S. Chakraborty, D. Li, GM. Shafiullah, R. D. Aughterson, and R. Ahuja, Applied Materials and Interfaces, DOI: 10.1021/acsami.7b03836 (2017).

Authors : Young-Hwan Kim, Kwang-Bum Kim e-mail :
Affiliations : Department of Materials Science and Engineering, Yonsei University, 134 Sinchon-dong, Seodaemoon-gu, Seoul 120-749, Republic of Korea.

Resume : Graphene has been extensively studied as an electrode material for supercapacitors due to its high electric conductivity, large specific surface area, and excellent chemical/mechanical stability.1,2 Due to the 2D nature of the graphene sheet, however, it tends to easily to form lamellar microstructures on a current collector during electrode fabrication. Restacking of the graphene sheets in the electrode greatly reduces the effective surface area of graphene and limits ion transport within the graphene electrode, which in turn leads to a decrease in the specific capacitance.3 Assemblies of graphene has been reported to convert 2D graphene sheets to a 3D structure of graphene could sustain its structure after being immersed in an electrolyte solution and was remarkably aggregation – resistant.4 In this study, we make 3D microsphere of graphene by using N-containing carbon and activate the produced 3D microsphere of graphene by potassium hydroxide. We report on activated graphene microspheres exhibited a large surface area of 1380 m2 g-1 and high micro-pore volume of 1.216 cm3 g-1 with a high specific capacitance of 254 F g-1 at 0.5 A g-1 and 226.7 F g-1 at 10 A g-1 in 1 M TEABF4/AN electrolyte. Detailed synthetic procedure, electrochemical properties of activated graphene microspheres will be discussed in the meeting.

15:30 Coffee break    
Authors : Ho Won Jang
Affiliations : Department of Materials Science and Engineering

Resume : Heterojunction nanostructures for high-performance water splitting photoelectrodes Ho Won Jang* Department of Materials Science and Engineering, Seoul National University, Korea *E-amil: After a brief introduction on the principles of solar water splitting, we introduce our recent achievements in photocathodes and photoanodes for water splitting. It is shown that solution-processed 1-dimensional (1D) TiO2 nanorods can be used as protection and antireflective layer for Si photocathodes. 1D TiO2 nanorods themselves have catalytic effect to split water. Using the 1D TiO2 nanorods and 0D Pt nanoparticles, we demonstrate the state-of-the-art performance of Si photocathodes with high stability. We are going to show chemical vapor deposition method to grow wafer-scale 2D transition metal disulfides (TMDs) such as MoS2 and WS2. Compared with a bare Si photocathode, substantially enhanced catalytic activity and stability of TMD/p-Si photocathodes are presented. We also present photoanodes based on vertically ordered hematite nanotubes synthesized by anodization, BiVO4-based type II heterojunctions synthesized by electrodeposition, and anion-doped TiO2 nanorods synthesized by hydrothermal method. We emphasized that the solution processes are promising for producing large-scale cost-effective 1D metal oxide nanostructures of high surface-to-volume ratios and crystallinity.

Authors : Dharmendra Pratap Singh and Redouane Douali
Affiliations : Unite de Dynamique et Structure des Materiaux Moleculaires (UDSMM), Universite du Littoral Cote d’Opale (ULCO), 50 Rue Ferdinand Buisson, 62228 Calais Cedex, France

Resume : Graphene-oxide (GO), prepared by Hummers method, was used to disperse in 4-n-octyl-4’-cyanobiphenyl (8CB) mesogen into different concentrations. The GO-8CB hybrid materials are characterized for soft energy storage applications along with their use in organic photovoltaics. The orientation of GO couples with the director of 8CB mesogen and provides a stable nematic phase for a wide range of temperature. The resultant orientation of hybrid materials can be controlled with the help of an external applied field. The mobility of charge carriers significantly depends upon the resultant orientation, concentration of GO and anchoring between GO and 8CB molecules. The soft energy storage and photovoltaic applications of these hybrid materials have been analysed and discussed. Email:

Authors : Franck Tessier 1, Erwan Ray 1, François Cheviré 1, Laurent Lemaître 2, Fabien Bonnier 2, Delphine Bazer-Bachi 2, Vincent Lecocq 2
Affiliations : 1 Institut des Sciences Chimiques de Rennes (UMR CNRS 6226), équipe Verres et Céramiques, Université de Rennes 1, F-35042 Rennes cedex, France 2 IFP Energies nouvelles, Rond-point de l'échangeur de Solaize, BP 3, F-69360 Solaize, France

Resume : AlPOxNy are the most studied materials among nitrided phosphates in heterogeneous catalysis. Such catalysts and AlPO4 (parent oxide) were tested in this work for the transesterification reaction of canola oil [1]. The final products are fatty acid esters (FAME) entering the composition of biodiesel and glycerine, a by-product (generally 10 to 15 wt.%) that can be further recycled and valued in industry if highly pure. High specific surface areas AlPO4 precursors have been prepared using hydrogel or citrate routes. Nitrided powders obtained after thermal reaction under ammonia flow keep high surface areas and nitrogen contents can be modulated depending on the experimental conditions. Both precursor and oxynitrides have been characterized by BET, oxygen and nitrogen analyses, infrared and NMR spectroscopies. The influence of the metal, the alcohol and the nitrogen content on the catalytic performances was also studied. AlPO4 and corresponding nitrided phases (with N wt.% < 10) produce higher catalytic activities for the transesterification of vegetable oils compared to that of the reference catalyst ZnAl2O4. [1] F. Tessier, E. Ray, F. Cheviré, L. Lemaître, F. Bonnier, D. Bazer-Bachi, V. Lecocq. Appl. Catal. B 185 (2016) 253-264

Authors : Parvathala Reddy Narangari1, Siva Krishna Karuturi1, Joshua Butson1, Rowena Yew1, Mykhaylo Lysevych2, Hark Hoe Tan1 and Chennupati Jagadish1
Affiliations : 1Department of Electronic Materials Engineering, 2The Australian National Fabrication Facility, Research School of Physics & Engineering, The Australian National University, Canberra, ACT 2601, Australia

Resume : Research on renewable energy technologies has been intensified from the past decade due to the scarcity of fossil fuels and global warming caused by the by-products from the consumption of fossil fuels. Hydrogen generation from solar water splitting is one of the promising routes to secure sustainable, green, storable and portable form of energy. Gallium nitride-based alloys, such as InGaN, are attractive for solar water splitting due to their tunable band gap, good crystal quality and stability against chemical corrosion which are requisites for solar water splitting. In addition, nanostructures made from these materials offer several advantages such as enhanced sunlight absorption, increased surface area and improved carrier separation which are critical for photocatalytic applications. In this work, we report on the fabrication of stable GaN-based nanopillar (NP) photoanodes for solar water splitting. Inductively coupled reactive ion etching (ICP-RIE) and random nanomask techniques were employed for the fabrication of n-doped GaN NPs. Structural and optical quality of GaN NPs was carried out by using SEM and photoluminescence studies, respectively [1]. The solar water splitting performance of GaN photoanodes was measured using a three-electrode photoelectrochemical PEC setup in NaOH electrolyte. NP photoanodes exhibit superior PEC performance compared to their counterpart planar photoanodes[2]. Most importantly, doping concentration and NP dimensions play a critical role in controlling the PEC performance of GaN NP photoanodes. Electrochemical impedance and diffuse reflectance measurements were used to analyze the PEC performance of GaN NP photoanodes. Our ongoing works on NP photoanodes based on InGaN multi quantum wells for improved photocurrent conversions will also be presented.

Authors : Brian Graves (1), Jean de la Verpillière (1), Michael De Volder (2), Adam Boies (1)
Affiliations : (1) University of Cambridge Department of Engineering, (2) University of Cambridge Institute for Manufacturing

Resume : TBA

Authors : William Parfitt, Ralph Jennings-Moors, Alex Pakpour-Tabrizi, Joseph Welch and Richard B. Jackman
Affiliations : London Centre for Nanotechnology and Department of Electronic and Electrical and Engineering, University College London, 17-19 Gordon Street, London, WC1H 0AH, UK

Resume : The vulnerability of water distribution systems in pressurised water nuclear (PWR) plants to materials failure, human error, natural disaster or deliberate attacks, which would have major public health, economic, and psychosocial consequences, is one of the main issues of concern to governmental agencies and reactor operators. UCL with BAE Systems plc are working on a family of diamond-based sensors for water quality control applications. This paper addresses diamond-based ion-sensitive field effect transistors (ISFETs) for the measurement of pH level within a water cooling system. A novel design is explored where all active regions of the device are diamond and a diamond-like carbon (DLC) passivation layer is used. This offers the first truly robust diamond ISFET sensor for deployment in the harsh environment encountered in PWR cooling systems. In addition, the deployment of such potentially robust devices in marine and river aquatic environments is of great interest and will be discussed.

Authors : Min Gyeom Kim, Yong Cheon Hong, In Seok Seo, Kyung Il Kim, Tae Whan Hong
Affiliations : Department of Material Science and Engineering Korea National University of Transportation Chung-ju 380-702 Republic of Korea

Resume : In recent years, magnesium and magnesium alloys are attractive materials for hydrogen storage applications, but activation, hydrogenation/dehydrogenation kinetics, thermodynamic equilibrium parameters and degradation behaviors have to be improved for applications.[1]. Especially, in case of the great improvement of the hydrogen properties of Mg alloys that can be achieved by Mg-Al-Zn-Hx. In this study, Mg-Ca-Hx is fabricated from Mg and Ca chips by hydrogen induced mechanical alloying(MA) for 72h, 96h under a high-pressure hydrogen atmosphere. The balls to chips mass ratios(BCR) are 30:1. The particles obtained are characterized by XRD and TEM, and absorbed hydrogen contents(AHC) were measured by TGA[2]. The results of XRD and TEM revealed that the Mg-Al-Zn-Hx peaks are broadened in the case of high BCR and the particles are composed of the nano crystalline phases less than 10nm with the amorphous phase.

Authors : Zhe Li, Chundong Wang, Yang Yang Li
Affiliations : Department of Physics and Materials Science, City University of Hong Kong 83 Tat Chee Avenue, Kowloon, Hong Kong 999077

Resume : Three-dimensional (3D) silicon (Si) thin films supported on a graphene scaffold were prepared as an anode electrode for lithium-ion battery. The as-prepared Si anode exhibited a gravimetric capacity as high as 1560 mAh g-1 at a current density of 797 mA g-1, and capacity retention of 84% after 500 cycles relative to the capacity value in the 50th cycle. Meanwhile, specific capacities of 1083 and 803 mAh g-1 were demonstrated after 1200 cycles at 2390 mA g-1 and 7170 mA g-1, respectively. The high specific capacity, and excellent cyclability and rate performance could be ascribed to the highly porous 3D architecture of graphene scaffold, which possesses good electrical conductivity and the feature of mechanical flexibility. The results presented here pave a new way to synthesize Si-graphene hybrid materials using microwave plasma-enhanced chemical vapor deposition as robust and scalable Si-based anodes for lithium ion batteries.

Authors : A. Kirakosyan, S. Yun, J. Kim, J. Choi*
Affiliations : Department of Materials Science and Engineering, Chungnam National University, Daejeon, Korea

Resume : Organometal halide perovskites become important in the photovoltaic and light emitting devices due to the compositional flexibility with AMeX3 formula (A is an organic amine cation; Me is a metal ion; X is a halogen atom), imposing a significant demand to develop a synthetic route toward new types of nanocrystals. Although chemical pathways for perovskites nanoparticles were developed on a basis of the reprecipitation method, a poor control of nucleation and growth process results in a large size polydispersity that induces the ambiguities associated with quantum confinement effect depending on their size. Here, a modified reprecipitation method is presented for synthesis of CH3NH3PbBr3 perovskite nanoparticles with a controlled nanoparticle size by systematically tuning the feed ratio of the precursors. Fine control of the nanocrystal size provides new insights into the quantum confinement effect observed in microscale and nanoscale perovskite materials, associated with the preferential growth in a lateral dimension and their energy bandgap.

Authors : Junghoon Yang, Yong-Mook Kang*
Affiliations : Department of Energy and Materials Engineering, Dongguk University-Seoul

Resume : Sodium manganese oxide (NaxMnO2) is a representative cathode material for sodium ion battery. Because of the preferred coordination of sodium ions in MnO2 layer, sodium manganese oxide can be constructed into either P2 or O3 structure. Among them, sodium manganese oxide with P2 structure exhibited better electrochemical performances compared to not only O3 structure but also other sodium ion cathode materials. However, low sodium content in its initial state is one of the biggest limitations that it has. Furthermore, many reports showed that the initial charge capacity of P2 phase is lower than that of its theoretical capacity. Nevertheless, any in-depth study for the low initial charge capacity of P2 phase has not been conducted so far. Meanwhile, the formation of sodium carbonates on the surface of layered Na ion cathodes looks typical and more severe compared to that on layered lithium ion cathodes. This phenomenon might be due to the reaction between atmospheric CO2 and sodium ions on the surface of cathode materials. The formation of surface sodium carbonate is definitely negative because it is electrochemically inactive and generally consumes significant amount of sodium ions during its formation. Our study indicated that the formation of sodium carbonate is one of the important reasons that deteriorate overall electrochemical properties including initial charge capacity and etc.. It may be because the formation of sodium carbonate affects the oxidation state of manganese on the surface, finally leading to lower electrochemical activity during first charge. So, in this study, we tried to study the natural formation of sodium carbonate on the surface of sodium manganese oxide and suggest the novel ways to enable the electrochemically inactive sodium carbonate activated with higher initial charge capacity.

Authors : Truong-Giang Vo, Jian-Ming Chiu, Yian Tai, Chia-Ying Chiang
Affiliations : Department of Chemical Engineering, National Taiwan University of Science and Technology, Taiwan (ROC)

Resume : Inspired by the functions and structures of the root and stalk of a turnip, a novel BiVO4/CuSCN heterojunction was constructed for photoelectrochemical water splitting, by initially fabricating bulky BiVO4 film (the root) and subsequently depositing p-type CuSCN nanorods (the stalk) on top. This BiVO4/CuSCN photoanode produced an enhanced photocurrent density of 1.78 mA cm-2 and hole injection efficiency of 82% at the potential 1.23 V vs. RHE. About 40% increase in photocurrent density coupled with a dramatic cathodic shift (~220 mV) in onset potential compared with bare BiVO4. The heterojunction also possesses external quantum efficiency of approximately 33% in the range from 350-450 nm with fairly high solar energy conversion efficiency (0.5%). The unique electrode architecture design favors the facile water splitting process over conventionally fabricated electrode by providing the more active sites and facilitates transportation and consumption of photoinduced holes, open a new route for the high-efficiency photoanodes.

Authors : Gong Xuefei, Li Shaohui, Lee Pooi See*
Affiliations : Materials Science and Engineering, Nanyang Technological University, Singapore

Resume : Fiber supercapacitor, as one kind of energy storage devices, have been received great attention due to its high flexibility, small size and light weight. With today?s modern weaving technology, they can be conveniently woven into fabric and integrated with other flexible gadgets, like sensors, energy harvesters, health monitors and sports monitors, for wearable applications. However, low energy density is one of the dominating factors limiting further developments of fiber-shaped supercapacitors. Carbon materials as anode electrode materials typically lead to moderate capacitance and energy density. In our work, we fabricated a fiber supercapacitor based on pseudocapacitive mechanism with asymmetric design that provides large specific capacitance and wide potential window, achieving the enhanced energy density of 3.7 mWh cm-3 with the corresponding power density of 190 mW cm-3. The energy density is comparable to that of a 4 V-500 µAh thin film lithium ion battery (0.5-10 mWh cm-3 at 1-5 mW cm-3). The series and parallel configurations demonstrate the easy scalability to deliver wider voltage window and larger stored energy. In addition, the encapsulated fiber supercapacitor could operate even after harsh soaking or washing solutions, like acid or alkaline. Our assembled device can be stitched onto fabric glove and delivers a high power output (fast charging a LED in seconds) for wearable applications.

Authors : Mickaël Pruvost, Annie Colin, Philippe Poulin, Cécile Monteux
Affiliations : ESPCI SIMM lab, Paris, France ESPCI SIMM lab, Paris, France Centre de Recherche Paul Pascal, Pessac, France ESPCI SIMM lab, Paris, France

Resume : The Internet of Things (IoT) is a new concept which aim at connecting everyday physical objects into the Internet without any human interaction. Eliminate the batteries and the wires for providing electrical power to these objects is a key to success for IoT. To overcome this problem, a promising route is harvesting mechanical energy from ambient vibrations and convert it into electrical power to fulfil energy demands. It could thus make captors, sensors, MEMS etc. autonomous. One way to convert mechanical energy into electrical power is to use variable capacitors. Composed of electrostrictive materials (i.e. for which dielectrics properties are modified under strain), these components are easily integrated into small devices. A recent approach is the use of polymers loaded with conductive nanoparticles. Near percolated networks of conductive particles are expected to yield materials with giant dielectric constant and electrostriction coefficients [1]. Nevertheless, the validation of such expectations and the development of electrostrictive nanocomposites remain challenging. It is necessary to finely control the morphology of the inner network formed by the particles within an elastic polymer. The aim of the present work is the development of near percolated reduced graphene oxide or carbon black network within an elastic polymer matrix, such as polydimethylsiloxane (PDMS). Two novel emulsions formulations routes are employed to achieve a fine control over the structure of the materials. In the first route, reduced graphene oxide (r-GO) solution is dispersed in the continuous phase of an emulsion made of PDMS droplets in water. The r-GO platelets are segregated after water removal between the PDMS droplets and can form near percolated networks controlled by the emulsion droplets. In the second route, droplets of a black-carbon solution are dispersed in a PDMS matrix. After water removal, black carbon are confine in the intern surface of pores. We have studied the dielectric properties of these two types of polymer nanocomposites at rest and under deformation. In the high filler concentration situation, the values of the permittivity are giant. The power harvestable with the composites has been measured too but remain still low (nW) because of high value of conductivity (typically higher than 10?7 S/m). Nevertheless, the high values of the piezoresistivity measured in the high filler concentration situation, open the road to use these material for stress or strain sensor applications considering their giant responses to mechanical deformations. 1. B. Vigolo, et al, Science 309, 920 (2005)

Authors : Lea de Biasi [1], Aleksandr O. Kondrakov [1], Holger Geßwein [2,3], Torsten Brezesinski [1], Pascal Hartmann [1,4], Jürgen Janek [1,5]
Affiliations : [1] Battery and Electrochemistry Laboratory, Institute of Nanotechnology; [2] Institute for Applied Materials, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany; [3] Helmholtz Institute Ulm for Electrochemical Energy Storage, Helmholtzstraße 11, 89081 Ulm, Germany; [4] BASF SE, 67056 Ludwigshafen, Germany; [5] Institute of Physical Chemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany

Resume : Li-ion batteries (LIBs) as energy storage devices have dominated the market since their commercialization in the early 1990s. However, automotive applications place high demands on the energy density and a new generation of LIBs is needed, especially for extended range vehicles. Two major strategies are currently pursued to improve the energy density of LIB full-cells using NCM cathode materials: (i) increasing the fraction of redox active Ni; and/or (ii) increasing the cut-off voltage on charge. In both cases, however, the lattice structure is subjected to strain, contributing to some extent to the capacity degradation with cycling. [1] Herein we present a comparison of the electrochemical and structural properties of low- and high-Ni NCMs in an attempt to identify the composition providing the optimum in terms of specific energy and stability. Crystallographic changes upon charging to 4.6 V vs. Li ? followed via in situ XRD ? were found to be accompanied by a large decrease (up to 8.0%) in unit cell volume. To make a fair comparison, energy densities were estimated and correlated with the XRD (Rietveld refinement) results. Overall, we show that low-Ni NCMs are capable of providing energy densities similar to high-Ni NCMs when operated at high voltages, but still undergo less significant changes in crystal structure. Yet, the cycling stability is also strongly dependent upon other factors such as gas evolution due to electrolyte decomposition. Summarizing, we demonstrate that it is of utmost importance to better understand the (voltage-dependent) degradation processes of LIBs using NCM cathode materials to be able to optimize their performance. [1] H.-J. Noh, S. Youn, C. S. Yoon and Y.-K. Sun, J. Power Sources, 2013, 233, 121?130.

Authors : Monalisa Ghosh, Venkatesh G, G Mohan Rao
Affiliations : Instrumentation and Applied Physics, Indian Institute of Science,Bangalore-560012;

Resume : Branched conical carbon tree-like nanostructures are grown by plasma enhanced chemical vapour deposition (PECVD) using electron cyclotron resonance (ECR) plasma system. These nanostructures have a nanotube aligned perpendicular to the surface of the substrate with carbon films branching from the central tube giving it a conical tree like appearance. These films have a high surface to volume ratio and can serve as a three dimensional (3D) anode for lithium ion battery. Thin films of these nanostructures are deposited on nickel seed layer of about 10 nm in thickness. The nanostructures are grown in a custom made ECR system with a microwave power of 500 W using acetylene and hydrogen gas in 2:1 ratio, at a working pressure of 7x10-4 mbar in the presence of a negative substrate bias of 200V. The performance of the material as anode of lithium ion battery has been studied with respect to lithium metal by assembling Swagelok type half-cell. Lithiation capacity for the first cycle is 172 µAhr cm-2 µm-1 and thereafter it decreased up to 54 µAhr cm-2 µm-1 after 5 th cycle. After initial capacity fall the specific capacity remains fairly constant up to 15th cycle. The cyclic voltammetry studies indicate repeatability in performance of the material as anode of lithium ion battery.

Authors : Yuya Ishii1, Taiki Nobeshima2, Keisho Omori1, Sei Uemura2, Heisuke Sakai3, Mitsuo Fukuda1
Affiliations : 1 Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology; 2 Flexible Electronics Research Center, National Institute of Advanced Industrial Science and Technology; 3 School of Material Science, Japan Advanced Institute of Science and Technology

Resume : Piezoelectric polymer micron/submicron fibers have unique features including piezoelectric properties, light weight, mechanical flexibility, and inherent waveguide structures. Thus, they are promising building blocks for energy producing or sensing devices used in wearable or bioimplant applications. In this paper, we demonstrated a unique piezoelectric-like response from electrospun fibers composed of the amorphous polymers poly(DL-lactic acid) (PDLLA) and poly(methyl methacrylate) (PMMA), whose films normally do not show a piezoelectric response. The waveguiding properties in the fibers were investigated. Electrospun fibers of PDLLA or PMMA with a mean diameter of ~730 nm or ~1 ?m, respectively, were deposited as disordered mats. Mat thickness changed depending on the applied voltage and its polarity, like the inverse piezoelectric effect of piezoelectric materials. The apparent piezoelectric constants of the PDLLA and PMMA mats were ~8500 and ~9700 pm/V, respectively, which are very large compared with those of common ceramics. The Young?s modulus was ~15.7 kPa for the PDLLA fiber mat and ~6.1 kPa for the PMMA mat, indicating they were quite soft. Aligned electrospun fibers of PDLLA or PMMA with mean diameters of 360 and 640 nm, respectively, were then fabricated. Their optical propagation losses were 0.63?3.6 dB/mm for the PDLLA fibers and 3.2?5.3 dB/mm for the PMMA ones at 630 nm.

Authors : A. Boileau (1), A. Cheik (2), M. Boisserie (2), P. Marie (2), A. Fouchet (1), A. David (1), C. Frilay (2), C. Labbé (2), F. Gourbilleau (2), U. Lüders (1)
Affiliations : (1) Normandie Univ, ENSICAEN, UNICAEN, CNRS, CRISMAT, 14000 Caen, France; (2) Normandie Univ, ENSICAEN, UNICAEN, CEA, CNRS, CIMAP, 14000 Caen, France

Resume : SrVO3 vanadate is a serious alternative material as a substitute for indium tin oxide (ITO) which suffers from poor mechanical properties and cost fluctuations. This material shows to be an excellent transparent conductor in its crystalline phase. However, the versatility of good SrVO3 layers for their integration into thermally sensitive technologies is currently constrained by its epitaxial growth at high temperature. Therefore, the growth and the electro-optical properties of SrVO3 films deposited at low temperatures were investigated and optimised for a wide variety of substrates. In this work, SrVO3 thin films have been deposited by Pulsed Laser Deposition onto SrTiO3 and LaAlO3 (100) oriented substrates as well as onto silicon and fused silica taken as typical substrates used in potential applications. A comparative study of the substrate effect on the crystallisation of SrVO3 and its electrical and optical properties is proposed. Furthermore, different strategies have been implemented to improve the transparent-conductive performances of the layers using post-thermal treatments with their pros and cons. These performances have been tracked by electrical and optical characterisations and faced to the structural characterisations and the chemistry of films. The room temperature resistivity, the plasma frequency and the transparency in the optical window 400-800 nm were notably used as comparative benchmarks. Both optical and electrical analyses confirm that SrVO3 deposited at low temperature can be a promising material for transparent conductive layers.

Authors : Yalin Zhu 1,2, Yu Chi 1, Shuen Liang 1,*, Jianhua Wang 1 and Lin Zhang 2
Affiliations : 1 Institute of Chemical Materials, China Academy of Engineering Physics (CAEP), Mianyang 621900, P. R. China; 2 Science and Technology on Plasma Physics Laboratory, Research Center of Laser Fusion, China Academy of Engineering Physics (CAEP), Mianyang 621900, P. R. China

Resume : Fast heat transfer is very important for practical application of encapsulated phase change materials. Herein, we combine the advantages of both highly thermal conductive shell materials and small capsule size, to prepare novel silver coated nanoencapsulated phase change materials (NanoPCMs). Dopamine surface activation was carried out on silica nanocapsules containing n-octadecane, followed by electroless plating in Tollen?s reagent. Chemical composition and crystallinity of the original silica nanocapsules, polydopamine modified NanoPCMs, and silver coated NanoPCMs were characterized by FT-IR, XPS, and XRD methods. Microstructure and morphology of these NanoPCMs were observed by SEM and TEM. Phase change property, thermal stability, thermal reliability, and thermal conductivity of these NanoPCMs were measured by DSC, TG, thermal cycling test, and laser flash method, respectively. These NanoPCMs crystallize mainly based on heterogenous nucleation and exhibit low supercooling, by introducing n-octacosane as nucleating agent. The silver coated NanoPCMs exhibit minor decrease of volume-based latent heat, compared with the original silica nanocapsules, and keep constant phase change properties during multiple melting/solidifying thermal cycles. More importantly, the apparent thermal conductivity of the silver coated NanoPCMs increases signi?cantly from 0.246 to 1.346 W/m?K. The silver coated NanoPCMs are promising for thermal energy storage and thermo-regulation applications.

Authors : Yalin Zhu, Hui Wang, Shuen Liang, Chunrong Tian, and Jianhua Wang*
Affiliations : Institute of Chemical Materials, China Academy of Engineering Physics (CAEP), Mianyang 621900, P. R. China

Resume : Morphological control was attempted on organosilica nanoencapsulated n-octadecane phase change material by adjusting various synthetic conditions, and the relationship between morphology and phase change property was investigated. The chemical structure and thermal stability of the nanocapsules were characterized by FT-IR spectroscopy and thermogravimetric analysis, respectively. The morphology and microstructure of the nanocapsules were observed by SEM and TEM, and the phase change property was determined by DSC and temperature-dependent XRD methods. With decreasing water-to-ethanol ratio, increasing cetyltrimethylammonium bromide (CTAB) concentration, or increasing NH3?H2O concentration, the morphologies of the NanoPCMs can be regulated from thin-shelled nanocapsules with bowl like, hemispherical, or spherical geometries to thick-shelled spherical nanocapsules or mesoporous particles. Meanwhile, the average diameter of the nanocapsules also increases obviously. It was demonstrated that the phase change properties of these nanocapsules are intimately related to their morphologies: thicker organosilica shells induce heterogeneous nucleation better and result in less supercooling, compared with the thinner ones. The methods and mechanisms proposed herein might be helpful to prepare various micro/nano encapsulated phase change materials through interfacial hydrolysis-condensation method, and optimize their morphologies and thermal properties.

Authors : Geon-Woo Lee , Myeong-Seong Kim, Jun Hui Jeong ,Kwang Bum Kim
Affiliations : Department of Materials Science and Engineering, Yonsei University, 134 Shinchon- Dong, Seodaemoon-gu, Seoul 120-749, Republic of Korea

Resume : Spinel Li4Ti5O12 (LTO) is one of the most attractive faradaic reaction materials for Hybrid supercapacitors (HSCs), because of its good Li-ion de/intercalation reversibility and near-zero strain during charge/discharge processes. Despite these advantages, LTO is not quite ready for its application on the high power HSCs because of its low electrical conductivity (10-13 S cm-1), which in turn leads to a poor rate capability. In order to improve the electrochemical properties of LTO, studies such as reduction of the particle size to nanoscale, surface modification, and carbon coating have been reported. MWCNT (Multi-Wall Carbon Nanotube) have unique 1-D tubular structure and high electrical conductivity. As it can entangle with the primary particles to form an interconnected conducting network, which can facilitate the electron transference, their existence can greatly enhance the conductivity between particles. Therefore, they can obviously increase the rate capability especially working at high current densities. In this study, we synthesized a LTO/Pristine-MWCNT (LTO/P-CNT) composite via a spray drying process without any MWCNT treatment. We nearly maintain the pristine carbon to utilize high electrical conductivity of MWCNT in the LTO/MWCNT composites to maximize high rate performance. More detailed on the synthetic procedure, morphology, electrochemical and structural properties of LTO/P-CNT microspheres will be presented at the meeting.

Authors : Yasutaka Mugita, Masatoshi Aramaki, Kazuhiko Yamazaki, Yoshimasa Funakawa, Osamu Furukimi
Affiliations : Kyushu University, Kyushu University, JFE Steel Corporation, JFE Steel Corporation, Kyushu University

Resume : Local elongation (El loc.) obtained by tensile test that relates to hole expansion ratio (?) depends on voids nucleation, growth and coalescence during tensile deformation. In this study, two kinds of 780MPa tensile strength-class steels. One was fine precipitation strengthened ferritic steel with 100% of ?, 8% of El loc. and the other was bainitic steel with 75% of ?, 5% of El loc. Voids nucleation, growth and coalescence during tensile test were examined by using Synchrotron X-ray. The test specimens were prepared by sequentially unloading of tensile force at six steps after maximum load and were observed 3-dimensionally voids by Laminography method. Number of voids nucleated in the fine precipitation strengthened ferritic steel that had higher El loc. was larger as compared to the bainite steel. The analysis results of carbon by Nano SIMS (Secondary Ion Mass Spectrometer) showed that carbon atoms segregated in grain boundaries of the bainite steel. Nano-indentation hardness increased largely on the grain boundaries of the bainite steel. From these results, it was concluded that the fine precipitates hardened ferrite steel has high El loc. and ?, because of suppressing carbon segregation which resulted in strain concentration at the grain boundaries.

Authors : Byung-Hoon Park, Jun-Hui Jeong, Suk Woo Lee and Kwang-Bum Kim
Affiliations : Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-Dong, Seodaemoon-Gu, Seoul 120-749, Korea

Resume : Currently, Li-ion batteries (LIBs) are considered the most promising power sources for portable electronic devices, clean transportation, and renewable energy storage facilities. Among various anode materials investigated for use in LIBs, Si has been considered as a promising anode material for due to its fascinating features such as high theoretical capacity (~4200 mAh g-1) and low operating potential vs. Li. However, a large volume change of Si during charge/discharge causes severe fading in the reversible capacity. In order to effectively exploit Si-based materials, recent research has focused on the synthesis of nanostructured Si or Si/carbon composite materials. Recently, multi wall carbon nanotube(MWCNT) can be used as a conductive carbon matrix on Si-based nanocomposites instead of graphene, because MWCNT has high theoretical electrical conductivity (105 ~ 107 S m-1) and high aspect ratio compared to the other carbon materials. It could form high electrical conductive porous structure that can not only efficiently accommodate the volume change of Si during the electrochemical reaction but also greatly improve electrical conductivity of the active material, potentially resulting in a significant improvement in battery cycling stability and rate capability. In this study, we developed a high-rate performance Si-based hybrid anode material with suitable cycling performance by developing a spray-assisted assembly process based on a combination of CNT and sucrose. It exhibits not only enhanced rate performance but also superior cycling performance, owing to the formation of the protective/binding carbon layers derived from the sucrose. More details will be discussed at the meeting.

Authors : Karolina Pietak [1], Michal Wrzecionek [1], Krzysztof Wozniak [3], Damian Trzybinski [3], Cezariusz Jastrzebski [2], S?awomir Podsiadlo [1]
Affiliations : [1] Faculty of Chemistry, Warsaw University of Technology, ul. Noakowskiego 3, 00-664 Warsaw [2] Faculty of Physics, Warsaw University of Technology, ul. Koszykowa 75, 00-662 Warsaw [3] Chemistry Department, Warsaw University, ul. Ludwika Pasteura 1, 02-093 Warsaw

Resume : Energy management indicates that in the future one of the main source of electricity will be renewable energy sources. Constant interest of new cheap, efficient and ecological photovoltaics devices stimulates study of new semiconductor materials and structures. Ag2ZnSnS4 is a compound that characterized by the same structure as Cu2ZnSnS4 - a popular semiconductor. It is assumed that Ag2ZnSnS4 will have similar properties as Cu2ZnSnS4, because Cu and Ag - the only ones that have been swapped - belong to the same group of the periodic table. Ag2ZnSnS4 consists of low cost, non-toxic elements and therefore has a chance to be used in the energy industry.The crystals of Ag2ZnSnS4 have been prepared by the Chemical Vapor Transport Method at a temperature of 600 - 1000 stC with different transport agent. The obtained materials have been characterized with X-ray diffraction, Raman Scattering Spectroscopy, Scanning Electron Microscopy and Energy-Dispersive X-ray Spectroscopy.

Authors : Ashwani Kumar and Ramesh Chandra
Affiliations : Nanoscience Laboratory, Institute Instrumentation Centre, Indian Institute of Technology Roorkee, Roorkee - 247667, India

Resume : Metal oxides are potential candidates for energy storage devices like supercapacitors and rechargeable batteries because of their several advantages such as natural abundance and lower price. This research work is focused on the fabrication of 2-D metal oxide nanostructured materials, which can have superior electrochemical performance to the bulk materials. The several chemical methods are being used to synthesize metal oxide nanostructures which involve toxic reagents, solvents and introduction of byproducts. However, physical vapour deposition (PVD) methods provide an eco-friendly route to fabricate 2-D metal oxide nanostructures with clean surface morphology. In this report, the fabrication of binder free supercapacitor electrode of MnO2 nanosheet on Nickel (Ni) coated porous anodic aluminum oxide (AAO) substrate by DC magnetron sputtering, is presented for first time. Ni-coated porous AAO substrate acts as an excellent current collector, which enhances the specific capacitance of MnO2 to 649 F/g. The binder-free symmetric supercapacitor device delivered a high areal capacitance (112.6 mF/cm2), specific capacitance (194.23 F/g), good cyclic ability (89.83% retention in capacitance after 5000 cycles), energy density (4.2 Wh/kg), and power density (1.4 kW/kg).

Authors : Jang-Yeon Hwang, Yang-Kook Sun*
Affiliations : Hanyang University

Resume : The O3-type layered structured transition metal oxides appear to be attractive based on the success of using layered LiMO2 cathodes in LIBs. However, delivery of high capacity with good retention is a challenge in developing cathodes for rechargeable sodium-ion batteries. Herein, we proposed an enhanced O3-type NaMO2 cathode materials by strengthening the particle surface, which effectively minimize unfavorable reaction with electrolyte solution. This cathode exhibited high capacity and enhanced cycling stability as well as thermal stability. In this study, we also investigated the capacity fading mechanism through the posted cycled study via various analysis techniques. We believe that our approaches are considered as a plausible step to yield high energy density cathode materials for SIBs.

Authors : Nagendra. S. Chauhan, Bathula Sivaiah, Bhasker Gahtori, Ajay Dhar
Affiliations : 1. Academy of Scientific & Innovative Research (AcSIR), CSIR-National Physical Laboratory (CSIR-NPL) campus, New Delhi-110012, India. 2. Advance Materials & Devices, National Physical Laboratory, Council of Scientific and Industrial Research, New Delhi 110012, India.

Resume : Half- Heusler (HH) based semiconducting intermetallic compounds show high potential as thermoelectric materials for operation in the mid-temperature range (500 - 800°C) where waste heat is abundant, which could be harvested for generation of energy. In the present study, we report the realization of highest thermoelectric figure of merit (ZT) in compatible n-type Zr1-xHfxNiSn and p-type Zr1-xHfxCoSb0.9Sn0.1 HH alloys for thermoelectric conversion in the mid-temperature range. A ZT of 1.5 for n-type and 1.1 for p-type at 873K for synthesized HH alloys was achieved with a similar value of Seebeck coefficient, which is one of the prerequisite for efficient thermoelectric devices. Isoelectronic alloyed arc-melted ingot was high temperature sintered employing spark plasma sintering for synthesis of both n-type and p-type HH materials. Isoelectronic partial substitution at Zr site with its heavier homologue Hf results in intrinsic phase separation, which optimises the carrier concentration by energy filtering and therefore results in a higher power factor for both n-type and p-type HH materials. Additionally, an enhanced phonon scattering, owing to mass defect scattering and boundary scattering via. phase separation results in significant reduction in thermal conductivity thus effectively improving ZT.

Authors : Matthew Zervos (a), Eugenia Vasile (b), Eugeniu Vasile (c), Andreas Othonos (d)
Affiliations : (a)Nanostructured Materials and Devices Laboratory, School Of Engineering, University of Cyprus, Nicosia, 1678, PO Box 20537, Cyprus. (b)(c)Politehnica University of Bucharest, Bucharest, 060042, Romania (d) Laboratory Of Ultrafast Science, School Of Physical Sceineces, University of Cyprus, Nicosia, 1678, PO Box 20537, Cyprus.

Resume : Metal oxide semiconductor nanowires (NWs) such as SnO2, In2O3, TiO2 etc. have been investigated extensively in the past and have been used for the realization of energy storage and conversion devices such as solar cells, super capacitors and for the photo catalytic generation of H2 .These are n-type, wide band gap metal oxide semiconductors so they require doping to increase their conductivity as in the case of Sn doped In2O3 NWs which is a transparent conducting oxide used extensively in solar cells. Similarly p-type metal oxide semiconductors such as Fe2O3 nanocrystals have recently been deposited on n-type Sn:In2O3 NWs to promote the photo catalytic generation of H2 generation [1]. However most p-type metal oxides suffer from high resistivity. In contrast metal sulfides are p-type semiconductors with a high conductivity so they do not require doping and may be readily combined with n-type metal oxides to make p-n junctions. For instance Sn:In2O3/CuS core-shell p-n junction NWs obtained via the deposition of Cu over Sn : In2O3 NWs and processing under H2S were used as counter electrodes in a quantum dot sensitized solar cell [2]. Transition metal sulfides like NiS and NiS2 are still being actively investigated to promote the photo catalytic generation of H2 [3] so here we describe our latest work on the properties of Sn:In2O3/NiS2 core-shell NWs obtained by the deposition of Ni over Sn:In2O3 NWs grown on metal foils and processing under H2S. We show that Sn:In2O3/NiS2 NWs consisting of a cubic bixbyite Sn:In2O3 core and a surface shell of NiS2 quantum dots with a cubic crystal structure and diameters of a few nm?s may be obtained on metal foils such as Ni and Mo as well as on a C fiber network. The Sn:In2O3 NWs form a p-n junction in contact with NiS2 giving rectifying current voltage characteristics and form a stradlling type I heterojunction where electrons are confined in the n-type Sn:In2O3 core and holes in the p-type NiS2 shell as shown by the self-consistent solution of the Poisson-Schrödinger calculations. We discuss the differences in the electron affinity and band gap of NiS2 , NiS and Sn:In2O3 but also the band alignment and the different types of p-n junction that occur in the context of photo catalytic generation of H2. Our initial results show that the Sn:In2O3/NiS2 NWs on the metal foils can reach current densities > 5 mA/cm2 at 1.5 V in alkaline electrolyte and appear promising for the photo catalytic generation of hydrogen. [1] Yang et al., ACS Appl. Mater. Interfaces 2015, 7, 26482?26490 [2] Zervos et al, J. Phys. Chem. C, 2016, 120 , pp 11?20 [3] Luo et al., ACS Appl. Mater. Interfaces 2017, 9, 2500?2508

Authors : Ghada H. Ahmed?, Jun Yin?, Riya Bose? , Lutfan Sinatra?, Erkki Alarousu?, Emre Yengel? , Noktan M. AlYami?, Makhsud I. Saidaminov?, Yuhai Zhang?, Mohamed N. Hedhili?, Osman M. Bakr? , Jean-Luc Brédas?# , and Omar F. Mohammed*?
Affiliations : King Abdullah University for science and technology (KAUST)

Resume : Engineering the surface energy through careful manipulation of the surface chemistry is a convenient approach to control quantum confinement and structure dimensionality during nanocrystal growth. Here, we demonstrate that the introduction of pyridine during the synthesis of methylammonium lead bromide (MAPbBr3) perovskite nanocrystals can transform three-dimensional (3D) cubes into two-dimensional (2D) nanostructures. Density functional theory (DFT) calculations show that pyridine preferentially binds to Pb atoms terminating the surface, driving the selective 2D growth of the nanostructures. These 2D nanostructures exhibit strong quantum confinement effects, high photoluminescence quantum yields in the visible spectral range, and efficient charge transfer to molecular acceptors. These qualities indicate the suitability of the synthesized 2D nanostructures for a wide range of optoelectronic applications.

Authors : Keisuke Watanabe, Hirofumi Ide, Morihiko Nakasaki, Akihisa Takeuchi, Masatoshi Aramaki, Osamu Furukimi
Affiliations : Sanyo Special Steel Co., Ltd.; Sanyo Special Steel Co., Ltd.; Sanyo Special Steel Co., Ltd.; Japan Synchrotron Radiation Research Institute; Department of Materials Science and Engineering, Kyushu University; Department of Materials Science and Engineering, Kyushu University

Resume : Center porosities due to solidification contraction during continuous or ingot casting could remain, ever after bar rolling and forging. To eliminate these defective porosities, it is effective to minimize the porosity generation during casting and to close them by optimizing the plastic forming conditions such as rolling and forging. Numerical analysis and experimental verification are used for optimizing plastic forming conditions. To evaluate the closure of porosities, hydrostatic pressure integral, which is the integral value of stress triaxiality, is commonly used. Although some experiments have been conducted on an artificial porosity of a millimeter size, there are no studies comparing experiment results and FEM analysis with the closure behaviors of a micron size porosity in a steel ingot. In this study, the shape change of center porosities during hot compression on Fe-0.25wt%C carbon steel, and stainless steel, Type316L, were sequentially, nondestructively and three-dimensionally observed by synchrotron X-ray laminography. Consequently, it was found that porosities of Type316 L were easier to be closed than those of Fe-0.25wt%C, while FEM results had the same tendency that the hydrostatic integration of Type316L had a larger value than that of Fe-0.25wt%C.This is because Type316L has a smaller work hardening coefficient in the tested temperature range than Fe-0.25wt%C.

Authors : Bo Reum Lee, Mi Gyoung Lee, Ho Won Jang
Affiliations : Seoul National University

Resume : Tungsten oxide have been developed as a promising water splitting material due to its appropriate band-edge position and moderate hole diffusion length. Also, It can absorb large range of wavelength including visible light because of its proper band gap. Solar water splitting using metal oxide nanorods is suitable for hydrogen production due to their large surface area and short distance for holes to diffuse. Among the various oxide nanostructure fabrication technologies, hydrothermal synthesis is the most simple and eco-friendly technology because pre-existing technologies often need vacuum equipment or etching process. However, the hydrothermal synthesis of WO? nanorods without seed layer on substrate such as FTO/glass is difficult to be achieved due to the poor adhesion between WO? nanorods and FTO/glass. Herein, we report the synthesis of WO? nanorod arrays without seed layer for water splitting. Furthermore, to enhance photoelectrochemical properties, BiVO?/WO? heterojunction anodes were fabricated by all-solution process. BiVO? nanodots were formed by pulsed electrodeposition on WO? nanorods synthesized by hydrothermal method. The photocurrent density of BiVO?/WO? heterojunction anodes was double that of bare WO? nanorod arrays at 1.23 V vs. RHE. This all-solution process enables the eco-friendly technology to fabricate efficient water splitting anode.

Authors : Sangwon Park, Jung Hoon Ha, Jeong Min Park, Byung Won Cho, Heon-Jin Choi
Affiliations : Yonsei university, Korea Institute of Science and Technology

Resume : With the growing interest of the flexible properties in energy storages, flexible active materials and current collectors are key elements for Lithium ion batteries (LIBs). Among flexible current collectors, carbon textile has been used for flexible LIBs because of cost-effectiveness, reasonable chemical stability, high electrical conductivity, and mechanical flexibility. Meanwhile, Si has been considered as attractive anode materials for LIBs due to the high theoretical capacity of 4,200 mA/g. However, Si is brittle and has a large volume change about 400 % during insertion of Li into Si that degrades the capacity significantly after cycling. In terms of these problems, silicon nanosheets are the ideal framework for fast lithium storage since it can provide high specific surface area. Herein, we have investigated flexible LIBs using Si nanosheets on carbon textile composites (SCCs). SCCs showed the high areal capacity about 3.35 mAh/cm2 and capacity retention of 98% even after 200 cycles. It showed excellent stability for repeatable bending. These findings can be contributed to fabricating other high performance electrode and current collector composites for flexible LIBs.

Authors : Nagaraju Sykam and G. Mohan Rao
Affiliations : Nagaraju Sykam, Research Scholar, Dept. of Instrumentation and Applied Physics, Indian Institute of Science Bangalore, 560012; Prof. G Mohan Rao, Dept. of Instrumentation and Applied Physics, Indian Institute of Science Bangalore, 560012

Resume : Carbon materials play considerable role towards energy and environmental applications in a fast growing world. Energy storage and waste water treatment are the two major challenges in the global scenario. Exfoliated graphite, a worm like highly porous carbon nanostructured material exhibits excellent properties and is a potential candidate for many applications. Here, we report rapid and efficient preparation of exfoliated graphite with manganese oxide materials by using microwave irradiation technique, which is one of the most efficient energy sources. The as prepared material was characterized by X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FESEM) and fourier transform infrared spectroscopy (FTIR) techniques. The material showsexcellent electrochemical performance with high specific capacitance value of 166.6 F/g at a current density of 1 A/g under 1M Na2SO4 electrolyte solution. Also, the material shows unusual removal performance of various organic dyes such as congo red (CR) and indigo carmine (IC) from water. The effect of process parameters i.e., pH, contact time, and initial dye concentration on removal of dyes under aqueous solutions was investigated. The adsorption isotherms (Langmuir model), kinetics models (pseudofirst and pseudo-second-order) were used to study the dye adsorption mechanism. It is suggested that the mechanism of adsorption depends mainly on the random distribution of pores, as well as, surface area. The maximum adsorption capacity reaches 222.2 and 204.1 mg/g for IC and CR dyes at equilibrium under aqueous solutions. Keywords: Carbon materials, porous materials, exfoliated graphite, adsorption, supercapacitors.

Authors : Mengjie Qin, Gaogao Dong, Jie Xu, Yi Zhang, Yu Wang, Feng Gao* *Corresponding author: Prof. Feng Gao,, Tel: +8613096956133
Affiliations : State Key Laboratory of Solidification Processing, MIIT Key Laboratory of Radiation Detection Materials and Devices, USI Institute of Intelligence Materials and Structure, School of Material Science and Engineering, Northwestern Polytechnical University, Xi?an, 710072, China

Resume : Sr0.9La0.1TiO3 thermoelectric ceramics with nano-sized Ag (Sr0.9La0.1TiO3/xAg, x=0.05, 0.10, 0.15, 0.20) and Ti (Sr0.9La0.1TiO3/yTi, y=0.05, 0.10, 0.15, 0.20, 0.30, 0.40) metal particles as additives were prepared by conventional solid state reaction method, and the influences of metal particles adding content on the microstructure and thermoelectric properties had been investigated. XRD characterization confirmed that the main phase was perovskite Sr0.9La0.1TiO3, accompanying with a small amount of metal phase. SEM images showed that all samples were dense, and the metal particles accumulated at the grain boundaries, which can form a local structure of complex network, contributing to increase the electrical conductivity. Raman spectra of samples before and after annealed in Ar+C atmosphere showed a great difference, resulting from the creation of oxygen vacancies and changes of Ti-O bond vibration and rotation modes. Adding nano-sized metal particles can increase the electrical conductivity and improve thermoelectric properties effectively. The maximum ZT value of 0.37 was obtained for Sr0.9La0.1TiO3/0.30Ti samples at 1073 K, accompanying with the relative high Seebeck coefficient of -336 ?V/K and low thermal conductivity of 2.14 W/m/K. This work suggested a route for using nano-sized metal particles to enhance thermoelectric properties of oxide thermoelectric ceramics.

Authors : Md. Selim Arif Sher Shah, Jooyoung Lee, Byungwon Lim and Pil J. Yoo*
Affiliations : Md. Selim Arif Sher Shah - School of Chemical Engineering, Sungkyunkwan University; Jooyoung Lee and Byungwon Lim - School of Advanced Materials Science & Engineering, Sungkyunkwan University; Pil J. Yoo - School of Chemical Engineering and SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University

Resume : Oxygen reduction reaction (ORR) is the cathodic process generally occurring in renewable energy devices such as, fuel cells and rechargeable metal-air batteries. Due to the slow kinetics of ORR, Pt has been preferred as the main catalyst. However, it is rare and exhibits poor long-term stability and low tolerance to methanol or CO. In order to resolve these issues, herein, we report N, P and S ternary doped graphene-based porous carbon foam synthesized through a template-free and self-assembly means using graphene oxide with 2-aminothiazole, branched polyethylenimine and phytic acid, followed by carbonization. The obtained carbon foam showed meso- and macropores with high specific surface area and pore volume. Notably, the best catalytic performances exhibited an onset and a half-wave potential of 0.97 and 0.82 V, respectively vs. standard hydrogen electrode and near four electron transfer pathways for ORR, which is closely comparable to those of the commercial 20 wt.% Pt/C catalysts. In addition, our synthesized materials have shown superior stability even in the later uses. Therefore, we anticipate that this catalyst would serve as a low-cost and highly efficient electrocatalyst for renewable energy applications.

Authors : Dmitry Bocharov1, Oleg Lisovski1, Stephan Kenmoe2, Sergei Piskunov1, Yuri F. Zhukovskii1, and Eckhard Spohr2
Affiliations : 1Institute of Solid State Physics, University of Latvia, Riga, LV-1063 (Latvia) 2Department of Theoretical Chemistry, University of Duisburg-Essen, Essen D-45141 (Germany)

Resume : Solar light-driven hydrogen evolution is in focus of modern material research. Among the different developing technologies, there is particular interest towards metal oxide photocatalysts in the form of various 1D nanostructures. Nowadays, a mismatch between the regular structures that can be synthesized and the largest structures that are feasible for computer simulation is still essentially large. For example, study on water adsorption at nanotube (NT) surfaces in addition to DFT requires simulation within TD-DFT and MD methods, although the latter ones are computationally costly. Traditionally, infinite slab model is used as an approximation of a large NT surface, but precision of this approach is rather insufficient. To eliminate this drawback we propose three simplified models of a relatively large TiO2 NT unit cell suitable for computational-power demanding methods (such as TD-DFT and MD simulations) based on infinite slab models with additional constraints. We use the energy of water adsorption, equilibrium adsorbate-surface distances and calculated density of state (DOS) as criteria for model estimate. After analyzing viability of the models, we draw a conclusion concerning suitability of the proposed models to serve as an approximation of either inner or outer surface of a NT.

Authors : Gulsen Baytemir, Firat Es, Rasit Turan
Affiliations : Middle East Technical University Physics Department, Center for Solar Energy Research and Applications (GUNAM); Middle East Technical University Micro and Nano Technology Department, Center for Solar Energy Research and Applications (GUNAM); Middle East Technical University Physics Department, Center for Solar Energy Research and Applications (GUNAM)

Resume : Among all other technologies, crystalline Silicon based solar devices are the dominant technologies with more than 90% share of the commercial market. The working principle of a c-Si solar cell device is based on electron-hole pairs generation inside the bulk by absorption of sunlight, diffusion of carriers through the junction region and separation of the charges by the built in electric field. As photo-generated carriers may be created away from the space charge region due to low light absorption in longer wavelengths, the minority carriers should be able to diffuse long enough to enter the vicinity of the space charge region. Therefore, for efficient collection of charges with less recombination, high purity Si material usage is crucial. On the other hand in order to enhance the optical absorption, Si material should be thick enough. In the end, to design a c-Si solar cell in with good electrical and optical properties, thick (high amount of) and high quality material usage is mandatory. In order to overcome this design problem alternative technologies and different geometries are being studied to obtain high efficient solar cells with low production cost. Recently, radial junction Si solar cells have been attracting attention as an alternative device geometry to reduce the cost of fabrication of crystalline Si photovoltaic cells. This new device structure is a promising candidate not only for higher optical absorption, but also for better carrier collection. This structure has a high density array of Si nano/micro wires and it facilitates to separate the direction of carrier collection from the direction of light absorption. Consequently, in radial junctions, collection of photogenerated minority carriers which have shorter diffusion lengths is more accessible than in conventional planar junctions. Therefore there is no need to use high purity material to obtain higher efficiencies. In this work, metal assisted chemical etching was used to obtain pillar structure on 500 µm thick, single side polished, p type mono crystalline silicon with boron doping wafers. It is a simple and low cost method besides its controllable fabrication. However, before obtaining micropillar structure, 30 nm Au layer was evaporated on the samples and annealing study was performed to decrease bulk lifetime since the aim of this study is to show that radial structure is also useful for low quality materials. At the end at 1000C, for 40 min. annealing under nitrogen atm., it was observed that bulk lifetime is very low. After this step, before MAE, photolithography technique was performed. The photoresist dots which have approximately 1.5 µm thickness act as a mask to a gold thin layer which will be a catalyst for MAE. After thermally evaporation of 25 nm Au layer, an ultrasonic lift-off process was followed to obtain a thin gold layer which has holes. When the samples are subject to an etchant contains HF and oxidative agent the silicon beneath the thin noble metal layer is etched much faster than the silicon. In this work, 65 mL HF, 10 mL H2O2 and 200 mL water solution was used for MAE. Consequently, this thin gold layer was etched faster than the holes and wire array structure was generated by holes. After metal assisted etching, aqua regia solution (HNO3:HCl=1:3) was used to remove residual Au catalyst. As a next process step, using standard process steps, radial junction solar cells will be formed. Moreover, at the same time conventional planar solar cells will also be formed for comparison.

Authors : Wanli Gao, Ozlem Sel, Hubert Perrot
Affiliations : Sorbonne Universités, UPMC Univ. Paris 06, CNRS, UMR 8235, LISE, F-75005, Paris, France.

Resume : In supercapacitors, periodical ion insertion/deinsertion or adsorption/desorption affects the electrode structure and thereby its mechanical integrity, causing long-term cycling performance deterioration. It is thus crucial to monitor in situ mechanical properties together with ion transport to better understand the correlation between mechanical and electrochemical evolution of electrodes, and in fine design of efficient high-rate functioning electrodes. Therefore, an approach capable of tracking the electrochemical and viscoelastic evolution of electrodes during cycling is urgently required. The combination of electrochemical quartz crystal microbalance (EQCM) and its coupling with the electrochemical impedance (ac-electrogravimetry) is proposed herein to monitor the evolution of the electrochemical properties of the electrodes, allowing the species? interfacial transfer mechanisms to be investigated in a time-resolved scale [1]. The corresponding mechanical property variations can be scrutinized by the electroacoustic analyses. As pertinent examples, the methodology combining EQCM, ac-electrogravimetry and electroacoustic tests was exploited to track the evolution of electrochemical and mechanical properties of (i) purely capacitive material, i.e. electrochemically reduced graphene oxide (ERGO) and (ii) pseudo-capacitive material, i.e. doped polypyrrole (PPy) electrodes upon cycling. For the ERGO, the electrochemical and mechanical properties seem to be affected by synthesis conditions such as the electrochemical reduction time, whereas for PPy electrodes, the electrochemical activity loss upon cycling is likely due to an increase in the rigidity of polymer electrode [2]. [1] C. Gabrielli, J.J. Garcia-Jareno, M. Keddam, H. Perrot, F. Vicente, Ac-electrogravimetry study of electroactive thin films. II. Application to polypyrrole, Journal of Physical Chemistry B, 106 (2002) 3192-3201. [2] W. Gao, O. Sel, H. Perrot, Electrochemical and viscoelastic evolution of dodecyl sulfate-doped polypyrrole films during electrochemical cycling, Electrochimica Acta, 233 (2017) 262-273.

Authors : R. Kumar, K. Bergum, H. N. Riise, E. Monakhov, B. G. Svensson
Affiliations : Department of Physics, Center for Materials Science and Nanotechnology (SMN), University of Oslo, Oslo, Norway

Resume : Cuprous oxide (band gap ~ 2.2 eV) with ?intrinsic? p-type conductivity is a nontoxic, low cost, and abundant material, has been a subject of extensive study with high potential as absorber layer in a tandem heterojunction solar cell structure based on silicon. Cu2O thin films were deposited using direct current (DC) magnetron sputtering system (Semicore Triaxis) on quartz substrates in a controlled atmosphere (O2|Ar ratio) at 400 ?C deposition temperature. Thin films analyzed by X-ray diffraction were polycrystalline Cu2O. As-grown polycrystalline Cu2O films were annealed at 900 ºC for 3 minutes in vacuum (pressure ~10-1 Torr) in order to enhance the optical and electrical properties. After annealing Cu2O films become more transparent. The mobility and carrier density increased while resistivity decreased with annealing temperature. The Cu2O thin films were implanted by various doses of hydrogen ions from 5E13, 1E14, 4E14, 1E15 and 2E15 cm-2 with 35 keV at room temperature. A series of heat treatments at 100 ?C, 200 ?C, 300 ?C, 400 ?C, 500 ?C, and 600 ?C temperatures has been performed. The impact of hydrogen dose and post annealing temperature were investigated. A correlation was established between mobility, carrier density and hydrogen implantation values. The Cu2O films annealed at low temperature from 100 ?C to 600 ?C in Ar to promote hydrogen passivation of prevalent intrinsic acceptors and tune the carrier concentration for optimum performance as absorption layer. The optical transmission spectrum in the wavelength range from 300 nm to 1500 nm was measured using a setup with spectrophotometers, a deuterium?halogen light source, and an integrating sphere. The room temperature as well as temperature dependent Hall effect measurements (LakeShore 7604) using the van-der Pauw method were employed to determine the mobility, resistivity, and carrier concentration of the Cu2O thin films. We found a trend that carrier density decreased (~ 9.6E+13 1/cm³ for 2E15 cm-2) while mobility and resistivity increased (~ 26 cm²/VS and 2.4 K? cm for 2E15 cm-2) as the hydrogen dose goes from lower to higher concentration. The impact of post annealing of thin films revealed that mobility goes high at 300 ?C (~ 26 cm²/VS for 2E15 cm-2) while carrier density and resistivity goes low (~ 9.6E+13 1/cm³ and 2.4 K? cm for 2E15 cm-2) at 300 ?C temperature.

Authors : Beniamino Iandolo, Elisabetta M. Fiordaliso, Sabrina R. Johannsen, Rasmus S. Davidsen, Maksym Plakhotnyuk, Marco Beleggia, Takeshi Kasama and Ole Hansen
Affiliations : Beniamino Iandolo; Rasmus S. Davidsen; Maksym Plakhotnyuk; Ole Hansen: Department of Micro-and Nanotechnology, Technical University of Denmark, 2800, Kongens Lyngby, Denmark; Elisabetta M. Fiordaliso; Marco Beleggia; Takeshi Kasama: Center for Electron Nanoscopy, Technical University of Denmark, 2800, Kongens Lyngby, Denmark; Sabrina R. Johannsen: DFM A/S, Danish National Metrology Institute, Matematiktorvet 307, 2800 Kongens Lyngby, Denmark

Resume : Black silicon fabricated by reactive ion etch (RIE) is intriguing for photovoltaics because of (i) lower optical reflectance than wet textured silicon, leading to potentially higher efficiency, and (ii) higher aesthetical value for building integrated panels. Due to the characteristic dimensions (100-500 nm) and the irregular shape of the nanostructures resulting from RIE, techniques used to characterize flat or wet textured wafers (e.g. 4-point probe, secondary ion mass spectroscopy) are not as reliable as when used on black Si. This in turn complicates understanding and optimization of processes such as emitter doping and passivation. We show how these challenges can be tackled by applying electronic and scanning probe microscopy, with a focus on black Si passivated by Al2O3 deposited by atomic layer deposition. High-resolution transmission electron microscopy confirms our success in tuning RIE towards minimal ion damage. Energy dispersed X-ray spectroscopy indicates that interdiffusion between Si and Al is limited. Off-axis electron holography enables visualization of p-n junctions and investigation of the fixed charges at the Si/Al2O3 interface. Kelvin probe force microscopy enables spatial mapping of the photovoltage in Si/Al2O3 with sub-µm resolution. The combination of these techniques give provide guidelines for realizing the full potential of black Si.

Authors : Lerato Y. Molefe, Nicholas M. Musyoka,Henrietta W. Langmi, Jianwei Ren, Patrick G. Ndungu
Affiliations : Lerato Y. Molefe, HySA Infrastructure Centre of Competence, Materials Science and Manufacturing, Council for Scientific and Industrial Research (CSIR), Pretoria, South Africa, Department of Applied Chemistry, Doornfontein Campus, University of Johannesburg, Faculty of Science, Johannesburg, South Africa; Nicholas M. Musyoka, HySA Infrastructure Centre of Competence, Materials Science and Manufacturing, Council for Scientific and Industrial Research (CSIR), Pretoria, South Africa; Henrietta W. Langmi, HySA Infrastructure Centre of Competence, Materials Science and Manufacturing, Council for Scientific and Industrial Research (CSIR), Pretoria, South Africa; Jianwei Ren, HySA Infrastructure Centre of Competence, Materials Science and Manufacturing, Council for Scientific and Industrial Research (CSIR), Pretoria, South Africa; and Patrick G. Ndungu, Department of Applied Chemistry, Doornfontein Campus, University of Johannesburg, Faculty of Science, Johannesburg, South Africa

Resume : Metal organic frameworks (MOFs), zeolites, carbons and porous polymers have been well investigated as adsorbents for hydrogen storage applications. However, these materials are still yet to meet all the specified standards and characteristics stated by the United States department of energy?s 2020 hydrogen storage targets for on-board applications [1]. Furthermore, for intended practical applications, these materials have to be shaped into a mechanically stable and more utilizable form due to the downsides of their powdery appearance [2]. Therefore, there is always a need for investigations for ways of achieving complementing properties of the pristine powdered materials without adversely compromising their intrinsic characteristics. The approach of this study was to utilise the flexibilities of polymer of intrinsic microporosity (PIM-1) for the design of new adsorbent composite materials which can easily be prepared in large quantities. Monolithic bodies of MOF@polymer composites materials that possess improved requisite properties resulting from the synergistic effects of compositing PIM-1 and MIL-101(Cr) were obtained in this study and tested for H2 storage applications. Moreover, the handling of the composite material was easier compared to the crystalline powder MOF. Keywords: Hydrogen storage, adsorbents, polymer of intrinsic microporosity, MOF-composites References 1. Lim, K.L et al. Chem. Eng. Technol., 33, 2010, 213?226. 2. Ren, J. et al. Int. J. Energy Res., 39, 2015, 607?620.

Authors : Xoliswa L. Dyosiba, Jianwei Ren, Nicholas M. Musyoka, Henrietta W. Langmi, Mkhulu Mathe, and Maurice S. Onyango
Affiliations : Xoliswa L. Dyosiba - Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Private Bag X680, Pretoria, South Africa -HySA Infrastructure Centre of Competence, Materials Science and Manufacturing, Council for Scientific and Industrial Research (CSIR) Pretoria, South Africa; Jianwei Ren - Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Private Bag X680, Pretoria, South Africa -HySA Infrastructure Centre of Competence, Materials Science and Manufacturing, Council for Scientific and Industrial Research (CSIR) Pretoria, South Africa; Nicholas M. Musyoka - HySA Infrastructure Centre of Competence, Materials Science and Manufacturing, Council for Scientific and Industrial Research (CSIR) Pretoria, South Africa; Henrietta W. Langmi - HySA Infrastructure Centre of Competence, Materials Science and Manufacturing, Council for Scientific and Industrial Research (CSIR) Pretoria, South Africa; Mkhulu Mathe - HySA Infrastructure Centre of Competence, Materials Science and Manufacturing, Council for Scientific and Industrial Research (CSIR) ; Maurice S. Onyango - Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Private Bag X680, Pretoria, South Africa.

Resume : Hydrogen at room temperature (300 K) is a mixture of 75% ortho-H2 and 25% para-H2. Such conversion can be promoted in the presence of an engineered solid surface such as metal-organic framework (MOF) materials. Ortho-H2 can be detected using nuclear magnetic resonance (NMR) and quantified by integrating the Fourier transformed Free Induction Decay (FID), while para-H2 does not produce any NMR signal. In this work, waste PET-derived MIL-101(Cr) materials were synthesized as cost-effective catalysts to enrich para-H2 by flowing ultra-purity H2 gas at 77 K. NMR was employed to quantify the presence of para-H2 when an unknown sample was compared to a normal H2 sample. The achievement from this study will contribute to the building-up of a continuous para-H2 generation system Keywords: Metal-organic frameworks, waste PET, para-hydrogen, nuclear magnetic resonance References [1] K. Fukutani, T. Sugimoto. Prog. Surf. Sci., 2003, 88, 379?348. [2] G. Buntkowsky, B. Walaszek, A. Adamczyk, Y. Xu, H.H. Phys. Chem. Chem. Phys., 2006, 8, 1929?1935.

Authors : Inês Cruz, Marta Costa, Paula Parreira, Clara Pereira, M. Cristina Martins, André Pereira
Affiliations : Inês Cruz (IFIMUP and IN ? Institute of Nanoscience and Nanotechnology and Department of Physics and Astronomy, Faculty of Science University of Porto); Marta Costa (REQUIMTE/LAQV, Department of Chemistry and Biochemistry, Faculty of Science University of Porto); Paula Parreira (i3S (INEB) ? Instituto de Investigação e Inovação em Saúde, Univ. of Porto); Clara Pereira (REQUIMTE/LAQV, Department of Chemistry and Biochemistry, Faculty of Science University of Porto); M. Cristina Martins (i3S (INEB) ? Instituto de Investigação e Inovação em Saúde, Univ. of Porto); André Pereira (IFIMUP and IN ? Institute of Nanoscience and Nanotechnology and Department of Physics and Astronomy, Faculty of Science University of Porto, Porto)

Resume : Helicobacter pylori (H. pylori) is a gram-negative bacterium that colonizes the gastric mucosa of over 50% of the world?s population1. This human gastric pathogen is thought-out as the etiologic agent of several gastric disorders, as chronic active gastritis, ulcers, gastric atrophy, intestinal dysplasia, lymphoma and invasive adenocarcinoma2. A remark on the gastric cancer since is the second most deadly type of tumor and it is the fourth most common cancer worldwide2. The current eradication treatment relies on antibiotic-based therapies that have revealed to be inefficient in about 20% of the patients3. The treatment would be improved with a targeted oral drug delivery system, with the therapeutic agents delivered directly onto affected sites and maintaining high drug concentration for the exact time needed4. An innovative solution for H. pylori eradication based on chitosan particles decorated with specific ligands to H. pylori where previously developed by us5. To improve the treatment, chitosan encapsulating magnetic nanoparticles is herein proposed. More specifically, the work will focus on new methodologies of synthesis of the magnetic nanoparticles6 coated with chitosan leading to a final core-shell nanoparticles and micrometric binders. The particles will be characterized by TEM and XRD to study the morphology, particle size as well as the crystallinity. Moreover, ZFC-FC and isothermal magnetic properties performed by SQUID will be presented to unveil the magnetic character of the nanoparticles. References 1. Wroblewski, L E et al. Clin. Microbiol. Rev. 23(4), 713-739 (2010). 2. Parreira, P et al. Crit Rev Microbiol. 42(1), 94-105 (2016). 3. Gonçalves, I C et al. Expert Rev. Anti-Infect. Ther. 12, 981?992 (2014). 4. Hao, S L et al. Mol. Pharm. 11(5), 1640?1650 (2014). 5. Gonçalves, I C et al. Acta Biomater. 33, 40-50(2016). 6. Pereira, C et al. Chem. Mater. 24(8), 1496?1504 (2012).

Authors : Q. Abbas, P. Przygocki, P. Babuchowska, P. Ratajczak, F. Béguin
Affiliations : Institute of Chemistry and Technical Electrochemistry, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland

Resume : Carbon/carbon capacitors in aqueous electrolyte can be charged up to 1.6 V by applying neutral aqueous lithium sulfate or sodium sulfate electrolytes. Such voltage, higher than the thermodynamic window of water (1.23 V), is owing to the trapping of hydroxyl anions in the porosity of the negative electrode, which downshifts hydrogen evolution potential according to the Nernst equation [1-2]. Despite the scientific interest of this new system, a number of hurdles still need to be overcome to make it at least as attractive as capacitors in organic electrolyte. To enhance the energy, we proposed a dual-function electrolyte containing lithium sulfate (Li2SO4) and potassium iodide (KI) as voltage and capacitance enhancers, respectively, leading to approach the energy of an EDL capacitor in organic electrolyte. Owing to the presence of KI, polyiodides are confined in the porosity of the positive electrode, creating a hybrid capacitor which exhibits twice higher capacitance as compared to its EDL counterpart [3]. In order to extend the operation of this family of capacitors to low temperatures, methanol has been added to neutral aqueous electrolytes. The capacitors could operate down to -40°C, temperature at which hydrogen storage in the negative electrode is quenched, and consequently self-discharge dramatically reduced [4]. However, such electrolytes display a relatively low conductivity which is not favourable for high power. Recently, we have circumvented this disadvantage by introducing aqueous electrolytes with eutectic properties which enable the capacitors to operate down to -40°C displaying high energy and high power. The various steps which lead to the present state of deliverable of aqueous electrolytes based capacitors will be critically discussed during the presentation. Acknowledgements The authors are grateful to the Ministry of Education of Poland for supporting this work under the project DS - 03/31/DSMK/0348/2017. References 1. L. Demarconnay, E. Raymundo-Piñero, F. Béguin, F. Béguin, Electrochem. Comm. 12 (2010) 1275. 2. Q. Gao, L. Demarconnay, E. Raymundo-Piñero, F. Béguin, Energy Environ. Sci. 5 (2012) 9611. 3. Q. Abbas, P. Babuchowska, E. Fr?ckowiak, F. Béguin, J. Power Sources 326 (2016) 652. 4. Q. Abbas, F. Béguin, J. Power Sources 318 (2016) 235.

Authors : Bin Wang
Affiliations : institute of chemical materials, china academy of engineering physics

Resume : In this work, the flexible fiber-shaped supercapacitors have been fabricated by using the conductive polymers as the electrodes. The prepared fiber-shaped electrodes show good mechanical properties and excellent electrochemical performances. They can be easily knoted, twisted and woven into different shapes without sacrificing their electrochemical properties.

Authors : Yan Song, Jianhong Dai, Yuying Chen, Ruiwen Xie
Affiliations : Harbin Institute of Technology at Weihai

Resume : Magnesium hydride is one of promising hydrides for on board applications. However, it's high thermodynamic stability and slow kinetics impede the practice application. Many efforts have been made to improve the hydrogen storage properties of magnesium hydride, such as inducing defects aiming to reduce its thermodynamic stability. Point like defects (such as dopant and vacancy) can effectively reduce its thermodynamic stability but still can not match the targets of DoE. Recently, we study the influence of planar kind defects, such as the interface by inducing an atomic layers into the magnesium acting as a catalytic layer (Mg-CL) on the hydrogen storage properties of magnesium hydride via first principles calculations. The catalytic layer can effectively improve the thermodynamics of thin films of magnesium based alloys by reducing overall stability of the alloys and providing more activating sites for hydrogen to be adsorbed. Generally the sandwich structures are less stable than the bulk system, however the adsorption of hydrogen could stabilise this structure in some degree, which make the hydrogen adsorption energy lies in a reasonable energy range. Therefore the inserting of catalytic layers greatly improves the hydrogenation properties of Mg film. The hydrogen adsorption energy reaches a positive value of 0.089 eV in Mg(0001) film, but all the Mg-CLs win negative hydrogen adsorption energies. The smallest adsorption energies of hydrogen atom in Mg-Ti, TiAl, TiMn2 and Ni films are -0.991, -1.241, -1.6, and -0.663 eV, respectively. The electronic structure analysis illustrates that in the Mg-CL films CL and Mg both act as active sites to capture hydrogen atoms and strong interactions between H and its surrounding alloying elements are expectable. Thus, inserting of CL layers could promote the hydrogenation of Mg by creating an interfacial zone.

Authors : Samih Haj Ibrahim, Tomasz Wejrzanowski
Affiliations : Warsaw University of Technology, Faculty of Material Science and Engineering

Resume : Presented study concerns numerical models of the microstructure of open-porous electrodes for Molten Carbonate Fuel Cells (MCFC) and analysis of their behavior during the startup process. Numerical models of open-porous 3D microstructures were generated based on fabrication routes of real materials, including mixing of powders, tape casting and sintering processes. Each of the casting slurry components (nickel powder, liquid phase, porogen) is represented by spheres with the same size distribution and volume fraction as the powder particles in the real manufacturing recipes. Discrete element method (DEM) implemented in LAMMPs software with the granular package was applied in order to model the slurry and its sintering process. The validation of the model structures was performed via image analysis of both representative models and 3D images of the real microstructures obtained from micro-computed tomography. Finite element method (ANSYS Mechanical software) was applied to simulate compression of the porous structures. Operating temperature was taken into account by using material?s mechanical properties in that temperature (650°C). Bilinear model of plasticity was utilized to include plastic strain in our modeling approach. Stress distribution and total strain were analyzed. In order to study changes in the microstructure related to the deformation, quantitative image analysis was performed on models before and after simulations. Results were verified with profilometry of dents from current collectors on fuel cell electrodes after the operation.

Authors : Young Jin Song,1 Wan Jae Dong,1 Gwan Ho Jung, Kisoo Kim, Sungjoo Kim and Jong-Lam Lee*
Affiliations : Dr. W. J. Dong, Y. J. Song, S. Kim, Prof. J.-L. Lee Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea) E-mail: Dr. G. H. Jung, Dr. K. Kim POSCO, Pohang 790-300 (Korea)

Resume : Solar-driven water splitting is a promising technology to produce hydrogn fuels. Efficient oxygen evolution (OER) catalysts were required for water spliting, since hydrogen evolution is severely constrained by sluggish kinetics of OER. Thus, main challenge for water splitting is to lower OER overpotential and integration of catalysts with solar cells. Recently, most of reported OER catalysts are powders coated on glassy carbon or metallic foams with polymeric binders. However, there are distinct limitations like slow charge transfer, poor stability and impossibility to integrate with solar cells. Such problems can be solved by anodizing the electrodeposited Ni-Fe foil. The Ni-Fe foil has a film structure with flatness, so it could be used as the catalytic substrates of solar cells. Here, we fabricated Ni-Fe oxyhydroxide film by anodizing Ni-Fe film, which exbilits low OER overpotential of 0.251 V and excellent stability for 36 h in 1 M KOH solution. We also integrated the catalyst with an amorphous silicon (a-Si:H) solar cell to demonstrate a monolithic photo-assisted water splitting device with a structure of Ni-Fe foil / Ag (120 nm) / Al-doped ZnO (60 nm) / p-i-n a-Si:H (250 nm) / ITO (60 nm). When the device was illuminated under 100mW/cm2 AM 1.5G solar irradiation in the electrolyte, photocurrent lowered OER overpotential by 0.8 V. It was the first monolithic device which has a significant impact on large-area and highly efficient solar-driven water splitting devices.

Authors : B. Orayech and D. Saurel
Affiliations : CIC EnergiGUNE, Parque Tecnológico, C/Albert Einstein 48, 01510 Miñano, Spain

Resume : The critical role of energy storage is by now self-evident: they are indispensable for an increased share of renewable energy and electric vehicles. Considering the abundance of sodium resources, sodium-ion batteries (NIBs) are poised as an alternative to Li-ion batteries as sustainable electrochemical energy storage (EES) solution.[1?6] However, several technical challenges still remain to be addressed before the commercialization of NIBs, with the anode being one of them. Graphite has been employed as the anode for commercial lithium-ion batteries (LIBs) since 1991.[7] However, for NIB, a high degree of disorder of the carbon structure is needed to allow sodium insertion at positive voltages. Therefore, alternative anode materials are demanded. One family of candidates is nongraphitic carbon, which comes in the forms of ?hard carbon? (HC) or ?soft carbon? (SC).[8] For both SC and HC the amount of sodium ions that can be inserted at positive voltages between the graphene layers is greatly increased compared to graphite. The specificity of HC is to present an additional capacity traduced by a low voltage plateau (LVP). Since the pioneer work of Stevens and Dahn in the early 2000?s, the sloping voltage below 1V and the low voltage plateau are usually ascribed to defect assisted intercalation and packing of sodium within the voids opened between cross-linked graphitic layers, respectively, [9] although recent results demonstrate that it might be more complicated than that.[10] Due to this extra capacity due to the LVP, the effort of the community has been mainly focused in recent years on hard carbons and on improving their capacities by tuning their micro-porosity. Thus, there is tremendous need to understand deeply the sodium insertion/extraction mechanism into disordered carbons. In the present work an optimized PVC-based SC as active material for NIB negative electrode will be underlined. A comparative study of the performance of PVC-C compared to Sugar-HC with similar particle size and electrode preparation will be presented. Although it does not present the typical low voltage plateau of hard carbons, PVC-SC reaches an initial reversible capacity of 230mAh/g and retains 225mAh/g after 150 cycles at 24.8mA/g. At high current density of 1C (372mA/g), the electrode still can achieve a capacity of 175mAh/g with a Coulombic efficiency near 100%. The microstructure and the morphology of these carbons have been studied by coupling gas adsorption, powder X-ray diffraction (in-situ and ex-situ PXRD) and Small Angle X-ray Scattering (SAXS) measurements, which, by correlating with their electrochemical performance, had led us to identify the and identifying key-microstructural features at origin of the performance of PVC?SC and give new insights into the mechanism of sodium insertion into disordered soft and hard carbons. [11] [1] Kim, S. W.; Seo, D. H.; Ma, X.; Ceder, G.; Kang. Adv. Energy Mater. 2012, 2 (7), 710?721. [2] Kundu, D.; Talaie, E.; Duffort, V.; Nazar, L. F. Angew. Chem., Int. Ed. 2015, 54 (11), 3431?3448. [3] Luo, W.; Shen, F.; Bommier, C.; Zhu, H.; Ji, X.; Hu, L. Acc. Chem. Res. 2016, 49 (2), 231?240. [4] Pan, H.; Hu, Y.-S.; Chen, L. Energy Environ. Sci. 2013, 6 (8), 2338?2360. [5] Slater, M. D.; Kim, D.; Lee, E.; Johnson, C. S. Adv. Funct. Mater. 2013, 23 (8), 947?958. [6] Wenzel, S.; Hara, T.; Janek, J.; Adelhelm, P. Energy Environ. Sci. 2011, 4 (9), 3342?3345. [7] Nagaura, T.; Tozawa, K. Prog. Batteries Sol. Cells 1990, 9, 209. [8] Na-ion batteries for large scale applications: a review on anode materials and solid electrolyte interphase formation; Muñoz-Márquez, M. Á.; Saurel, D.; Gómez-Cámer, J. L.; Casas-Cabanas, M; Castillo-Martínez, E.; Rojo, T.; accepted to Advanced Energy Materials (2017). [9] D. A. Stevens and J. R. Dahn, J. Electrochem.Soc. 148 (2001) A803-A811. [10] C. Bommier, T. Wesley Surta, M.Dolgos and X. Ji, Nano Lett. 15 (2015) 5888?5892. [11] Ultra-microporous soft carbon as high performance active material for the negative electrode of sodium-ion batteries; Orayech, B.; Clarke, C.; Acebedo, B. and Saurel, D.; submitted.

Authors : Chao Li, Prof. Yu Li, Prof. Bao-lian. Su
Affiliations : a Laboratory of Inorganic Materials Chemistry (CMI) 61 rue de Bruxelles, B-5000 Namur, Belgium b State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology 122 Luoshi Road, 430070 Wuhan, Hubei, China

Resume : The bursting market demands for mobile electronics, electric vehicles and large-scale energy storage, prompted the quick development of batteries with high energy density, long circles and low costs. Conventional cathode materials are lithium transition metal oxide materials, such as LiFePO4, LiCoO2, which are short of energy density and rate performance. Recently, Li-S batteries attracted much attention due to its high theoretical capacity(1672mAh/g), however, sulphur suffers from low electron conductivity and redox shuttle effect. Selenium belong to the same main group of sulphur but with much better conductivity, while still undergo the dissolution of high-order polyselenides, giving rise to poorer cycle and lower coulombic efficiency. Several strategies which confine selenium inside of carbon materials like mesoporous carbon, carbon spheres and graphene has been demonstrated effectively. Metal-organic frameworks(MOFs), a class of porous material assembled by connecting metal ions and organic linkers, has been recognised as promising precursors for porous carbon materials. Due to abundant of metal parts and organic parts, pore shape, size, volume, and modification which exhibits uniform porosity and multitudinous structures. In this work, three kinds of aluminium based MOFs are synthesized, then porous carbon materials are obtained by calcination in high temperature. Finally?Selenium was confined in porous carbon derived by melt-diffusion strategy and showed improved performance of capacity, rate and cycle. It was also carefully evaluated by x-ray diffraction(XRD), scanning electron microscopy(SEM), transition electron microscopy(TEM), x-ray photoelectron spectroscopy(XPS), raman spectrum, cyclic voltammetry. The better electrochemical performance benefits from pores distribution, restricted solubility of selenium, polyselenide by micropores, thus effectively suppresses the shuttle effects. The simple efficient method provides a promising route towards high performance lithium and sodium batteries.

Authors : Paula Ratajczak, Patryk Przygocki, Qamar Abbas, Francois Beguin
Affiliations : Institute of Chemistry and Technical Electrochemistry, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland

Resume : Supercapacitors (SCs; also known as ultracapacitors) are high power and long cycle-life energy storage devices which attract a lot of research attention. It is well known that the operating voltage, and consequently the energy of SCs, is limited by the electrochemical stability of the electrode/electrolyte system [1, 2]. The main observable ageing symptom, initiated by increasing voltage, is the formation of gases and decomposition products blocking the porosity of carbon, with related decrease of capacitance and increase of resistance [2, 3]. Due to the uncontrolled potential range of electrodes, electrolyte decomposition may even occur when the voltage is lower than stability window of the electrolyte with the considered electrodes. For this reason, the combination of electrochemical online mass spectrometry (EOMS) and pressure measurement during high voltage operation appears as an interesting tool to detect the gaseous decomposition products and reveal the degradation mechanisms of SCs from the point of view of nanoporous carbon electrodes. In this study, the mass spectrometry (MS) signals of the evolved gases are recorded both after (post-ageing analysis) and during cyclic voltammetry investigations, galvanostatic charge/discharge and potentiostatic floating on SCs (in-operando investigations). As already observed, in aqueous medium, the contribution is due to di-hydrogen evolution from the negative electrode, and CO and CO2 due to oxidation of the positive electrode. To provide fundamental insights on the nature of side-reactions and facilitate the understanding of processes occurring at the electrode/electrolyte interface, the semi-quantitative estimation of the evolved gases from the leakage current and comparison to pressure records during electrochemical ageing appears to bring many important information regarding the ageing phenomena. In the presentation the results of these analyses will be discussed and strategies for optimizing SCs in view of high voltage performance and energy storage, as well as long cycle-life will be proposed. Acknowledgements The authors are grateful to the Ministry of Education of Poland for supporting this work under the project DS - 03/31/DSMK/0348/2017. References 1. M. Arulepp, J. Leis, M. Latt, F. Miller, K. Rumma, E. Lust, A.F. Burke, J. Power Sources, 162 (2006) 1460. 2. P. Ratajczak, K. Jurewicz, P. Skowron, Q. Abbas, F. Béguin, Electrochim. Acta, 130 (2014) 344. 3. P. Azais, L. Duclaux, P. Florian, D. Massiot, M.A. Lillo-Rodenas, A. Linares-Solano, J.P. Peres, C. Jehoulet, F. Béguin, J. Power Sources 171 (2007) 1046.

Authors : Roozbeh Siavash Moakhar (a,b,c), Nastaran Riahi-Nouri (a), Mahsa Jalali (b), Gregory Kia Liang Goh (b), Abolghasem Dolati (c), Mohammad Ghorbani (c)
Affiliations : (a) Niroo Research Institute, Chemistry and Materials Division, Non-Metallic Materials Group, Tehran, Iran (b) Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis, #08-03 Singapore 138634 (c) Department of Materials Science and Engineering, Sharif University of Technology, Tehran, 11155-9466, Iran

Resume : Photoelectrochemical (PEC) water splitting is one of the highly efficient and eco-friendly methods of production of H2 for renewable green fuel application. In this paper, we report a promising sunlight-driven TiO2 nanorods (NR) photoanode and decorated with silver-palladium (Ag-Pd) nanostructures for PEC water splitting. Fabricated photoanodes were fully characterized using field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-Ray diffraction (XRD) analysis and UV-vis spectroscopy. Decoration with bimetallic Ag-Pd nanoparticles is exhibited that play a vital role in boosting up the PEC performance by injecting hot electrons and excellent catalytic effect. Ultimately, the results were also compared with another promising Au-Pd bimetallic nanoparticles.

Authors : Dasom Jeon;Yeongkyu Choi;Yuri Choi;Nayoung Kim;Byeong-Su Kim;Jungki Ryu
Affiliations : Ulsan National Insititute of Science and Technology (UNIST)

Resume : Artificial photosynthesis has drawn great attention for decades as a promising solution to energy and environmental problems. For example, we can produce valuable chemicals (e.g., formate, synthesis gas, and methanol) from abundant carbon dioxide and water through a series of photoelectrochemical processes in a carbon-neutral manner. For the successful development of efficient and stable photosynthetic devices, it is critical to precisely assemble various functional materials such as semiconductors for exciton generation, conducting materials for exciton dissociation and charge transport, and redox catalysts for target-chemical reactions. Here, we report the improvement of an efficient and stable, hematite-based photoelectrode for solar water splitting by layer-by-layer assembly (LbL) of cationic graphene oxide (GO) nanosheets and anionic molecular metal oxides as a charge transporting/separation material and water oxidation catalyst, respectively. It was found that their serial deposition significantly develops the photocatalytic performance and stability of the hematite photoelectrode by promoting charge transport and transfer across the electrode/electrolyte interface. Unexpectedly, it was also found that deposition of alternating layers of cationic and anionic functional materials allow us to engineer work-function of hematite photoelectrode beneficial for charge transport by forming an interfacial dipole layer at the surface of hematite. We believe that the present study can provide not only a general and simple method to fabricate an efficient photosynthetic device, but also an insight to scientists and engineers for designing of a novel electrochemical/photoelectrochemical device. References 1. Qiushi Yin, Jeffrey Miles Tan, Claire Besson, Yurii B. Geletii, Djamaladdin G. Musaev, Aleksey E. Kuznetsov, Zhen Luo, Ken I. Hardcastle and Craig L. Hill, ?A Fast Soluble Carbon-Free Molecular Water Oxidation Catalyst Based on Abundant Metals.? Science 2010, 328, 342. 2. Jae Young Kim, Ji-Wook Jang, Duck Hyun Youn, Ganesan Magesh and Jae Sung Lee, ?A Stable and Efficient Hematite Photoanode in a Neutral Electrolyte for Solar Water Splitting: Towards Stability Engineering.? Adv. Energy Mater., 2014, 4, 1400476. 3. Jungki Ryu, Dong Heon Nam, Sahng Ha Lee and Chan Beum Park, ?Biocatalytic Photosynthesis with Water as an Electron Donor.? Chemistry-A European Journal, 2014, 20, 12020. 4. Dasom Jeon, Hyunwoo Kim, Cheolmin Lee, Yujin Han, Minsu Gu, Byeong-Su Kim and Jungki Ryu, ?Layer-by-Layer Assembly of Molecular Metal Oxide Catalysts for Photoelectrochemical Water Splitting.? Manuscript in preparations. 5. Yeongkyu Choi, Dasom Jeon, Yuri Choi, Taemin Lee, Nayoung Kim, Minsu Gu, Hyun-Wook Lee, Byeong-Su Kim and Jungki Ryu, ?Rational Assembly and Band Engineering of Functional Materials by Layer-by-Layer Assembly for Solar to Fuel Conversion.? Manuscript in preparations.

Authors : Dasom Jeon;Hyunwoo Kim;Yujin Han;Cheolmin Lee;Jungki Ryu*
Affiliations : Ulsan National Institute of Science and Technology (UNIST)

Resume : Hematite is one of the candidates for solar water oxidation owing to its proper band gap for water oxidation, abundance and easy synthesis. For their practical applications, however, there still remain many problems to be addressed such as a low photocurrent/stability under neutral pH condition and high onset potential for catalytic water splitting. To solve these critical issues, we developed a novel surface modification method to improve photocatalytic efficiency of hematite using layer-by-layer assembly (LbL) of cationic polyelectrolytes and anionic polyoxometalates (POMs) water oxidation catalysts. We found that the surface modification of hematite with polyelectrolytes (which is electrically and electrochemically inactive) and POMs led to the enhancement of photocurrent approximately 5 times and the cathodic shift of onset potential for water oxidation by about 400 mV. Unexpectedly, we also find that the LbL films also improve the stability of hematite films at the same time under neutral pH conditions. We believe that our findings can be further applied for assembly of various functional materials with different size and shape on virtually any kinds of photoelectrodes, providing a general and simple method to fabricate novel photoelectrochemical devices. 1. Q. Yin, J. M. Tan, C. Besson, Y. B. Geletii, D. G. Musaev, A. E. Kuznetsov, Z. Luo, K. I. Hardcastle and C. L. Hill, ?A Fast Soluble Carbon-Free Molecular Water Oxidation Catalyst Based on Abundant Metals.? Science 2010, 328, 342. 2. J. Y. Kim, G. Magesh, D. H. Youn, J. W. Jang, J. Kubota, K. Domen and J. S. Lee, ?Single-Crystalline, Wormlike Hematite Photoanodes for Efficient Solar Water Splitting.? Scientific Reports 2013, 3, 2681. 3. D. Jeon, H. Kim, C. Lee, Y. Han, M. Gu, B. S. Kim and J. Ryu, ?Layer-by-Layer Assembly of Molecular Metal Oxide Catalysts for Photoelectrochemical Water Splitting.? Manuscript in preparations. 4. Y. Choi, D. Jeon, Y. Choi, T. Lee, N. Kim, M. Gu, H. W. Lee, B. S. Kim and J. Ryu, ?Rational Assembly and Band Engineering of Functional Materials by Layer-by-Layer Assembly for Solar to Fuel Conversion.? Manuscript in preparations.

Authors : Agnieszka Zurawska1*, E.N. Naumovich1, Ryszard Kluczowski2
Affiliations : 1 Institute of Power Engineering - Research Institute, Department of High Temperature Electrochemical Processes, Augustowka 36, 02-981 Warsaw, Poland, 2 Institute of Power Engineering, Ceramic Department CEREL, Techniczna 1, 36-040 Boguchwala

Resume : Units based on solid oxide fuel cells (SOFC) have become a very promising alternative for energy generation because of very high efficiency and environmentally-friendly nature. It is applied in such system as combined heat and power systems (CHP) or solid oxide electrolysers (SOEC) which run in reverse mode to produce oxygen and hydrogen. One of the critical challenges that are faced by SOFC/SOEC units designers is the need for reliable sealing technology, which limits their commercialization. The main requirements for the seals are long-term stability in the high temperature SOFC environment (600-800°C) and maintenance of their integrity during thermal cycling, which means that the thermal expansion coefficient of the seal must be compatible with the steel and ceramic parts of the unit. The research was focused on manufacturing and testing of hybrid glass-mica seals that plays double role in the SOFC/SOEC designs: a barrier protecting hydrogen and oxidant from mixing and a structural element assuring proper distance between the following compartment of the units. In presented results selected solutions are compared in terms of final operational properties, with respect to different sources of materials and conditions of preparation. The row glass tapes were fabricated by tape casting process from glass powder and the finally shaped by laser cutting. The gas permeability tests in high temperatures were performed with the use of specially designed test station. Acknowledgement: Authors would like to acknowledge financial support from the Ministry of Science and Higher Education through the statutory grant in the Institute of Power Engineering (CPC/4/STAT/2016) and NCBR, Poland (project POIR.01.02.00-00-0013/16 NewSOFC, co-founded from the European Regional Development Fund under the Operational Programme Smart Growth

Authors : David Simeone1, Gordon James Thorogood2, Da Huo3, Laurence Luneville1, Gianguido Baldinozzi1, Joel Ribis1, Suzy Surble3
Affiliations : 1DEN/Service de Recherches Metallurgiques Appliquees, CEA, Universite Paris-Saclay, F-91191, Centralesupelec/SPMS/UMR-8085/LRC CARMEN, 92292 Chatenay Malabry, France 2ANSTO, Lucas Heights, NSW, Australia and Department of Nuclear System Safety Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka,Nagaoka 940-2188, Japan 3LEEL, NIMBE, CEA/CNRS, Universite Paris Saclay, 91191 Gif sur Yvette, France

Resume : used for nuclear waste immobilization matrices and fuel cells, are the result of disorder at the atomic scale. To investigate how order at the atomic scale induces disorder at a larger scale length, we have applied different techniques to study the atomic composition of a homogeneous La2Zr2O7 pyrochlore, a textbook example of such a structure. Here we demonstrate that a pyrochlore, which is considered to be defect fluorite, is the result of intricate disorder due to a random distribution of fully ordered nano-domains. Our investigation provides new insight into the order disorder transformations in complex materials with regards to domain formation, resulting in a concord of chemistry with crystallography illustrating that order can induce disorder.

Start atSubject View AllNum.Add
09:00 Plenary Session - Main Hall    
12:30 Lunch break    
Authors : Arzu KARAYEL, Oguz GULSEREN
Affiliations : Hitit University, Faculty of Arts and Sciences, Department of Physics, 19030 – Corum (Turkey); Bilkent University, Faculty of Science, Department of Physics, 06800 - Ankara (Turkey).

Resume : In this study, a supercapacitor model using first principles calculations based on density functional theory (DFT) has been explored. Bilayer graphene as electrode and ammonia as electrolyte are used in this graphene-based supercapacitor device. Both the combination of electrode and electrolyte are important in order to improve the energy storage capacity of the device. In our calculations, both the local density approximation (LDA) and van der Waals functional for exchange-correlation potential are considered. First, the adsorption of ammonia on monolayer graphene is studied. The different configurations and orientations of NH3 on monolayer graphene are investigated. The relative position of NH3 with respect to graphene can be hollow (H), top (T) and bridge (B), where NH3 is placed at the center of hexagon, on top of the carbon atom and between two carbon atoms, respectively, with orientations of NH3 being up and down with respect to the position of H atoms. Bridge case is found to be the most energetically favorable. Consequently, supercapacitor is formed from bilayer graphene system. After extensive structure optimizations, electronic structure is studied from density of states (DOS) calculations. Then, the quantum capacitances based on these DOS are calculated. For realistic modelling of these capacitor devices, it is necessary to include the effect of solution because of the electrolyte. The effect of the solvent environment on the electronic structure and the quantum capacitance of the graphene based supercapacitor systems have been studied using the nonlinear polarizable continuum model. Accordingly, based on the results of these simulations, appropriate devices are suggested. This work is supported by TÜBİTAK Project No: 114F118

Authors : B. Gadermaier, M. Wilkening
Affiliations : Institute for Chemistry and Technology of Materials, Christian Doppler Laboratory for Lithium Batteries, Graz University of Technology (member of NAWI Graz), 8010 Graz, Austria

Resume : Nanostructuring of electrodes can significantly improve materials characteristics like cycling behavior as well as overall charge transfer kinetics due to enlarged electrode-electrolyte interface [1]. We present a template-assisted synthesis route for transition-metal phosphate nanorods using biological templates. A great benefit of using biological templates is the versatility of its use since the template can be modified conveniently by genetic engineering [2]. The biological template, the bacteriophage M13 – a rod-shaped virus with 8 nm in diameter and about 1 µm in length – is covered by the active material FePO4 in a co-precipitation process giving rise to hollow nanorods that can be used as nanostructured cathodes in batteries [3]. Modifying the template even further allows for it to bind carbon nanotubes thereby forming a tight connection between the active material and the percolating network resulting in enhanced electronic conductivity in the nanostructured composite cathode. The as-such synthesized nanocomposite electrodes have a large surface as well as a superior percolating network. Results of electrochemical characterization such as cyclability, rate performance and specific capacities will be presented. 1. Liu, R., et al., Chemical Communications (2011) 47 (5), 1384 2. Moon, J.-S., et al., Mini-Reviews in Organic Chemistry (2015) 12 (3), 271 3. Lee, Y. J., and Belcher, A. M., Journal of Materials Chemistry (2011) 21 (4), 1033

Authors : Amjid Rafique* Usman Zubair,, Marco Fontana, Mara Serrapede, Stefano Bianco, Candido F. Pirria and Andrea Lamberti
Affiliations : a Politecnico di Torino, Dipartimento di Scienza Applicata e Tecnologia (DISAT), Corso Duca Degli Abruzzi, 24, 10129 Turin, Italy. b Istituto Italiano di Tecnologia, Center for Sustainable Future Technologies, Corso Trento, 21, 10129 Turin, Italy

Resume : Internet of things and big data acquisition demand portable and compatible energy storage devices for retrieving and processing information. Supercapacitors being high power, high rate capable and long cyclic life energy devices are promising candidates among its commercial counterparts. Aforementioned, energy requests can be addressed by integrating fiber shaped flexible supercapacitors onto physical substrates and textiles. Therefore, current collectors must be flexible and should be configurable into complex devices such as pacemakers, artificial skins, foldable displays, wireless sensors and smart cards. In current study, we report the two-steps electrodeposition of stoichiometric MnO2 nanoflakes on carbon fiber and their H-inserted MnO2-x phases for high performance flexible supercapacitors. The two-steps deposition of MnO2 enable to achieve uniform and crack free nanoflake-structured films. As deposited electrodes showed promising capacitive performance in neutral electrolyte (0.5 M Na2SO4) at slightly basic conditions with specific capacitance as high as 575 F/g. KOH-activation of the carbon fibers shows an improvement in capacitance up to 600 F/g at 1 A/g current density. We have also worked on a reliable and low cost approach to enhance the capacitive performance of these electrodeposited carbon fibers. The hydrogenation of these MnO2 electrodeposited electrodes exhibited remarkable improvement in capacitance up to 835 F/g. The superior capacitive performance can be attributed to the hierarchal deposition of two uniform, continuous and highly porous layers of stochiometric and H-inserted MnO2-x. Surface oxygen vacancies contribute to improve conductivity and kinetics of the surface redox reactions.

Authors : Susann Nowak, Guido Schmitz
Affiliations : Institute of Materials Science, University of Stuttgart Heisenbergstr. 3, 70569 Stuttgart, Germany

Resume : In the ongoing endeavor of miniaturization of sensors and micro-electro-mechanical systems, a miniaturized power source is one of the remaining challenges. A proposed solution for powering these devices are all-solid-state thin-film batteries. Over one hundred of these systems have been reported over the last decades and a few have already been commercialized. Another trend was the commercialization of lithium iron phosphate (LFP) in conventional batteries due to its excellent cycling stability and safety. But surprisingly, LFP was so far not well used in all-solid-state systems despite its promising properties. We combined LFP with the state-of-the-art thin-film electrolyte lithium phosphorous oxynitride (LiPON) and different anode materials (lithium, tin, silicon). The obtained batteries were characterized by temperature-dependent electrochemical methods, mainly using cyclic voltammetry (CV) and chronopotentiometry (CP). In contrast to similar batteries using lithium cobalt oxide as the cathode, it is demonstrated that the capacity of these batteries is strongly dependent on the temperature. Measurements of LFP/LiPON layers have been used to determine the part of the overpotential that is introduced by the interface in between cathode and electrolyte. It shows an Arrhenius activated behavior with an activation enthalpy of (52 -9) kJ/mol for a 200nm thick LiPON layer. TEM cross-section micrographs were used to determine the nature of the interface. Evidence is derived that the observed behavior of the interface is best explained by using a space-charge layer model.

Authors : Elena Marelli, Cyril Marino, Claire Villevieille
Affiliations : Paul Scherrer Institute, Electrochemistry Laboratory, CH-5232 Villigen PSI

Resume : The worldwide increased demand of energy and the need to limit the fossil fuel consumption urged scientists to develop cleaner and more efficient ways to produce and store renewable energies. Lithium-ion batteries (LiBs) are, since their first commercialisation in the early ‘90s, the technology of choice to power portable devices, thanks to the largest energy density stored. The limited availability of lithium and thus its expected increase in costs, however, favoured the development of the analogous sodium-ion batteries (NiBs). The larger atomic radius and ionisation potential of Na compared to Li, inevitably lead to a lower energy density in this family of batteries, which has to demonstrate long-term cycling stability and lower costs than the Li equivalent to hope for commercialisation. Based on the remarkable performance reported for P2-Na0.67Mn0.5Fe0.25Co0.25O2,[1] a new class of P2-layered cathode materials for NiBs, namely Na0.67MniFejCokAlzO2 (with i+j+k+z=1), was studied. The cobalt is believed to prevent the full reduction of the Mn(IV) to Mn(III) upon cycling, preventing the detrimental Jahn-Teller distortion in the layers. However, in order to reduce the toxicity and costs of this material, the cobalt content was decreased either by varying the ratio between transition metals[2] or by substitution with aluminium. A good compromise between Co content and electrochemical stability was found in P2-Na0.67Mn0.5Fe0.35Co0.15O2 while the Al-containing materials showed a surprisingly improvement in the electrochemical performance. 1. Liu, L., et al., High-Performance P2-Type Na2/3(Mn1/2Fe1/4Co1/4)O2 Cathode Material with Superior Rate Capability for Na-Ion Batteries. Advanced Energy Materials, 2015. 5(22): p. 1500944. 2. Marino, C., E. Marelli, and C. Villevieille, Impact of cobalt content in Na0.67MnxFeyCozO2 (x + y + z = 1), a cathode material for sodium ion batteries. RSC Advances, 2017. 7(23): p. 13851-13857.

Authors : Wolfram Kohs, Jürgen Kahr, Atanaska Trifonova
Affiliations : Wolfram Kohs, Jürgen Kahr, Atanaska Trifonova AIT Austrian Institute of Technology GmbH Center for Low-Emission Transport Electric Drive Technologies

Resume : Lithium-ion cells are powering cell phones, laptops, tools and electric driven cars today. However, their capacity is often considered as not totally satisfying. One approach to further increase the energy density is using high capacity cathode materials, or cathode materials with a higher working potential. Using these more sophisticated high-end materials the electrolyte cathode interactions and the formation of the cathode electrolyte interphase (CEI) come into focus, as these reactions determine the degradation, and thus the cycle life and safety of the system. In this contribution we would like to give a small insight into the chemical reactions occurring when combining carbonate based electrolytes with NMC and the high voltage spinel LNMO. The resulting decomposition products, and their dependency on the cathodes potential are measured using a GC-MS / IR combination. Commercially and laboratory made cathode materials are compared, different known additives are used. This work is realised in the course of the eCAIMAN project, which is generously co-funded by the European Union under the H2020 framework.

15:30 Coffee break    
Authors : Chengzhou Zhu, Shaofang Fu, Dan Du, Yuehe Lin*
Affiliations : School of Mechanical and Materials Engineering Washington State University

Resume : Recent years have witnessed the increasing production of the sustainable energy. Electrocatalysts play a central in these electrochemical energy devices and engineering advanced electrocatalysts in term of the more rational control of size, shape, composition and structure become a high priority. Specifically, the rapidly emerging studies on single-atom catalysts have aroused great attention in electrocatalysis thanks to the unique properties including high catalytic activity, stability and selectivity with maximum atom utilization. Herein, we will introduce our recent advances in constructing single-atom electrocatalysts and exploring their electrochemical application in oxygen reduction reaction (ORR). Fe-based carbonaceous catalysts, with Fe-N-C active sites, are the most promising nonprecious metal nanocatalysts for ORR. Rational design of Fe-N-C structures with single-atom feature allows the even dispersion of highly active Fe-N-C active sites and ensures the high ORR performance. We successfully synthesized Fe,N-codoped carbon nanotube aerogels and metal-organic framework-derived atomically dispersed Fe-N-based catalysts, both of which exhibited excellent ORR electrochemical performances superior to commercial Pt/C catalyst. Taking advantage of the novel synthetic strategies, advanced characterization technologies as well as theoretical modeling, more high-efficiency ORR catalysts with single-atom feature will be available and enable the large-scale application of fuel cell technology.

Authors : Yong Min Lee
Affiliations : Daegu Gyeongbuk Institute of Science and Technology (DGIST)

Resume : Surface And Interfacial Cutting Analysis System (SAICAS) is a new tool to measure adhesion properties of composite electrodes and membranes in energy storage and conversion devices. In particular, since the SAICAS can cut the sample to the thickness direction, we can measure the adhesion strength at a specific depth. In this work, we introduce a variety of studies on the adhesion property of the electrodes with different binder types, compositions, thickness, density, etc. Also, with composite membranes, we could apply the SAICAS to get some adhesion properties with and without electrolyte. We think this tool is very powerful to understand and elucidate the adhesion properties to design both composite electrodes and membranes.

Authors : Anna Szumska, Jacek A. Majewski
Affiliations : Faculty of Physics, University of Warsaw, ul. L. Pasteura 5, 02-093 Warszawa, Poland and Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, U.K; Faculty of Physics, University of Warsaw, ul. L. Pasteura 5, 02-093 Warszawa, Poland

Resume : Graphene and other two-dimensional layered materials (such as silicene, germanene) have emerged recently as very promising candidates for novel devices for the electronics, optoelectronics, spintronics, quantum computing, and recently also for thermoelectric applications. The figure of merit for thermoelectric devices favors systems characterized by: (i) large Seebeck coefficient and/or (ii) by as large as possible the ratio of electric to the thermal conductivity. The low dimensional systems are the most promising candidates to fulfill these conditions, since it is much easier to tune their properties by suitable structural modifications. Therefore, it has been proposed to introduce structural defects to these materials just to diminish their thermal conductivity. Here, we present results of ab initio calculations based on Nonequilibrium Green’s function and density functional theories for thermoelectric properties of graphene, silicene, and germacene nanoribbons with various structural defects. Further, we consider also two-dimensional (2D) hexagonal SiGe alloys. Our studies reveal that SiGe nanoribbons have much better thermoelectric characteristics than graphene, silicene and germacene. The figure of merit for 2D SiGe alloys reaches very promising values, exceeding the value of two (required for reasonable thermoelectric systems) already in very slightly defected SiGe.

Authors : Hariom JANI, Prince Saurabh BASSI, Sreetosh GOSWAMI, Soumya SARKAR, Ragavendran NAGARAJAN, Changjian LI, Mallikarjuna Rao MOTAPATHULA, Yonghua DU, Ping YANG, Siddhartha GHOSH, Lydia Helena WONG, Stephen PENYCOOK, Venkatesan THIRUMALAI
Affiliations : NUS Graduate School of Integrative Sciences and Engineering, National University of Singapore, Singapore; NUS Nanoscience and Nanotechnology Initiative - NanoCore, National University of Singapore, Singapore; Material Sciences and Engineering, National University of Singapore, Singapore; Singapore Synchrotron Light Source, National University of Singapore, Singapore; Institute of Chemical & Engineering Sciences, Agency for Science, Technology and Research (ASTAR), Singapore; Energy Research Institute @ NTU (ERI@N), Interdisciplinary Graduate School, Nanyang Technological University, Singapore; School of Materials Science and Engineering, Nanyang Technological University, Singapore

Resume : Hematite (α-Fe2O3), is a photoanode material candidate for application in Photoelectrochemical cell (PEC). It has an optical bandgap (~2.1eV) which straddles the water oxidation and reduction potentials, allowing it to drive water splitting by absorbing light. Its chemical resistance, non-toxicity and low cost, make it a promising material to manufacture hydrogen in an environmentally friendly way. Unfortunately, its poor electrical conductivity, carrier transport dynamics and absortivity, yield low solar-to-hydrogen conversion. Hence, Fe2O3 photoanodes are often doped to yield higher photo-currents. In my talk, I will present how we have used catalytic hydrogenation to enhance electrical performance of Fe2O3 thin films. We observe that hydrogen doping increases the electronic conductivity of Fe2O3 by 3 orders of magnitude, without changing its optical bandgap. Furthermore, X-Ray Absorption Near Edge Structure (XANES) spectroscopy shows that the enhancement in conductivity is concomitant with a shift in the Fe K-edge toward lower valence states, suggesting that hydrogenation leads to electron doping into Fe2O3 lattice. The novel hydrogenated phase of Fe2O3 is characterised by X-Ray Diffraction, Raman Spectroscopy, UV-Vis Spectroscopy and Scanning Tunnelling Electron Microscopy. We use Elastic Recoil Detection Analysis (ERDA) to prove that hydrogenation causes incorporation of H atoms in the Fe2O3 lattice, as opposed to creating any vacancies or defects. Lastly we use this catalytic hydrogenation technique to increase the PEC performance of Fe2O3 photoanodes.

Authors : Navnita Kumari, B. R. Mehta
Affiliations : Indian Institute of Technology Delhi

Resume : In family of Transition Metal Chalcogenides (TMDs), Molybdenum disulfide (MoS2) is a highly capable material for energy harvesting applications such as lithium ion batteries (LIBs), photocatalysis, photoelectrochemical as well as electronic device etc. MoS2 nanoflakes and nanoflowers were prepared by one step hydrothermal route with uniform morphology in temperature range 150-220°C. From XRD and HRTEM it has been clearly observed that grown nanoflakes have hexagonal primitive structure. Orientation of grown nanoflakes and flowers shows at (002) plane with interplanar spacing 0.61 nm and (100) plane having 0.32 nm which confirmed growth of MoS2 in desired pattern and signature of hexagonal arrangement. Temperature affects the formation of nanoflakes conversion towards 3D nanoflowers. FTIR transmission spectrum shows the vibrational bonding around wave number 467 cm-1 which is signature peaks of bonding between S-Mo-S with different morphology its showing shift in nature which may be due to another bonding of Mo-O at around 451 cm-1 which is grown at temperature 220°C. In Raman spectra prepared nanostructure shows a difference between two consecutive peaks is the range of 18 cm-1 to 24 cm-1 which indicates its change towards monolayer to few layers. The distance between two consecutive peaks is around 19 cm-1 which is clear signature of monolayer formation. Conversion of indirect band gap to direct band gap in monolayer structure has been confirmed by photoluminescence (PL) studies. This monolayer to few layers structures potentially important for different device application point of view.

Authors : Kaoruho Sakata; Takashi Hisatomi; Yosuke Goto; Blanka Magyari-Köpe; Peter Deák; Taro Yamada; Kazunari Domen
Affiliations : Department of Chemical System Engineering, School of Engineering, the University of Tokyo; Department of Electrical Engineering, Stanford University; Bremen Center for Computational Materials Science, University of Bremen

Resume : Photocatalytic and photoelectrochemical (PEC) water splitting under visible light irradiation has been extensively investigated for production of solar hydrogen as a potential energy resource for the future. La5Ti2Cu1-xAgxS5O7, a solid solution of La5Ti2CuS5O7 and La5Ti2AgS5O7, is a semiconductor studied for photocathode material. In this study, the band structure and effective mass of La5Ti2Cu1-xAgxS5O7 solid solutions are analyzed by density functional theory (DFT) calculations to reveal the effect of the composition on the band structure and the anisotropy in the conductivity. The correlation between the composition and the band gap was well approximated with a square curve, representing the band gap bowing. The theoretical calculation presented in this study suggests that the band gaps of La5Ti2Cu1-xAgxS5O7 solid solutions were governed principally by the structure of the top of the valence band. The effective masses of holes and electrons in La5Ti2Cu1-xAgxS5O7 are estimated from the band structure. Both holes and electrons have smaller effective masses in the b-axis direction than in the other directions, testifying the highly anisotropic electronic properties. The wave functions at the valence band maximum and the conduction band minimum are both delocalized along the b-axis only, forming parallel channels for electron and hole conduction. These results support the experimental observation that photoexcited carriers tend to migrate one dimensionally.

18:00 Best Student Presentation Awards Ceremony and Reception (Main Hall)    
Start atSubject View AllNum.Add
Authors : Drew Parsons*, Manickam Minakshi*, Motohiro Kasuya†, Kazue Kurihara†∥
Affiliations : * School of Engineering and Information Technology, Murdoch University, 90 South St, Murdoch, WA 6150, Australia † Institute of Multidisciplinary Research for Advanced Materials and ∥ WPI-AIMR, Tohoku University, Sendai 980-8577, Japan

Resume : We present a theoretical model that describes how nonelectrostatic (van der Waals) interactions of electrolyte ions influence adsorption of the ions at electrode surfaces. The model enables the dependence of the capacitance on the specific electrolyte to be described using a modified Poisson-Boltzmann formalism employing quantum chemical calculations for van der Waals interactions. We compare lithium electrolytes with PF6− , BF4− and ClO4− and Cl− anions in water and in propylene carbonate, with graphite electrodes. Van der Waals interactions affect the physisorption of ions and thereby control electrolyte specificity in the capacitance of supercapacitors. We build a theory of pseudocapacitors by adding chemisorption to the same model, chemically binding ions to the electrode surface. This introduces an additional degree of dependence of the capacitance on the specific electrolyte. Capacitance varies with the strength of the chemisorption binding energy. Significantly, even though physisorption and chemisorption refer to two distinct ion-surface interaction mechanisms, the chemisorption contribution to the total free energy is partially determined by the nonelectrostatic (van der Waals) physisorption energy of the binding ion. In this way nonelectrostatic properties of ions influence the overall energy storage capacity of a pseudocapacitor.

Authors : Francois Aguey-Zinsou
Affiliations : Materials Energy Research Laboratory in Nanoscale School of Chemical Engineering The University of New South Wales Sydney, Australia

Resume : Storing hydrogen in materials is based on the observation that metals can reversibly absorb hydrogen. However practical application of such a finding has found to be rather challenging especially for vehicular applications. The ideal material should reversibly store a significant amount of hydrogen under moderate conditions of pressure and temperature. To date, such a material does not exist and the high expectation of achieving the scientific discovery of a suitable material simultaneously with engineering innovations seems out of reach. One of the key materials with capability to deliver high capacity reversible hydrogen storage is magnesium (Mg). Upon hydrogen absorption, Mg spontaneously converts to the thermodynamically favored β-MgH2 phase, but this leads to hydrogen release/uptake far from the desired low temperatures and fast kinetics. Conversion to the metastable γ-MgH2 phase is believed to lead to improved hydrogen sorption properties. However, experimental verification of such a hypothesis has remained distant and the capability of γ-MgH2 to lead to simultaneously improved thermodynamic and kinetic properties has remained hypothetical. In this work, we report the electrochemical synthesis of nanosized Mg leading to the formation of a mixed γ/β hydride phase upon hydrogen absorption with a high γ-MgH2 content (29.6%). More remarkably, full release of hydrogen from these phases occurred at 200 °C only and upon hydrogen reabsorption at 100 °C, the γ/β-MgH2 mixture was restored. It was thus possible to determine for the first time the effect of γ-MgH2 on the kinetic and thermodynamic properties of the Mg/H2 reaction and its potential to lead to improved hydrogen sorption.

Authors : Sergey Borisenko
Affiliations : IFW-Dresden

Resume : Electronically driven nematic order is often considered as an essential ingredient of high-temperature superconductivity. Its elusive nature in iron-based superconductors resulted in a controversy not only as regards its origin but also as to the degree of its influence on the electronic structure even in the simplest representative materials FeSe and BaFe2As2. Here we utilized angle-resolved photoemission spectroscopy and density functional theory calculations to study the influence of the nematic order on the electronic structure of FeSe and BaFe2As2 and determine its exact energy and momentum scales.

Authors : Xuanhua Li, Shaohui Guo, Bingqing Wei
Affiliations : State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Lab of Graphene (NPU), Xi'an, 710072, China.

Resume : Photocatalytical water splitting of MoS2 nanomaterials based on plasmonic nanoparticles (NPs) has been limited because of the insufficient utilization of plasmonic hot spots, which is an important strategy for efficient light harvesting. Here, we design a high-performance photocatalyst Au multimer@MoS2 core-shell hybrid structures to address this issue. The Au NP’s multimer with 5-10 nm inter-particle distance realized by a pre-decoration is employed as a plasmonic component. As expected, rationally structural arrangement provides a strong near-field coupling at their inter-particle gaps of Au NPs and then gives rise to strong absorption enhancement, which leads to the significant improvement of exciton generation and dissociation in the Au-MoS2 junctions. Theoretical modeling and surface enhanced Raman scattering (SERS) have been used to demonstrate the enhanced optical effect; and the photoluminescence (PL) and electrochemical measurements are adopted to clarify the improved electrical effect. As a result, a 240.2% increment in hydrogen gas production amount (2997.2 μmol/g) is achieved as compared to that of the pure MoS2 spheres (881.6 μmol/g). The hydrogen gas production amount of Au multimer@MoS2 spheres is among the highest values reported in the plasmon-enhanced photocatalytic hydrogen production.

Authors : Jessica C. McGlynn, Irene Cascallana-Matías, James P. Fraser, Isolda Roger, James McAllister, Haralampos. N. Miras, Mark D. Symes and Alexey Y. Ganin
Affiliations : School of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK

Resume : Transition metal chalcogenides have attracted significant interest as hydrogen evolution catalysts in recent years. Currently, attention has been given to MoS2 as a potential replacement for platinum, the HER catalyst of choice. In the bulk form, MoS2 exists naturally as the semiconducting 2H-MoS2 phase which is a remarkably inactive catalyst. Nanostructuring leads to the exposure of catalytically active edge sites; however this tends to reduce the stability of the catalyst. Therefore, in the long term, efforts must be turned towards the application of catalytically active materials in the bulk form. Chemical exfoliation via lithium intercalation allows for the transition from semiconducting 2H-MoS2 to the metallic 1T-MoS2 polymorph which is catalytically active even as the bulk material. However, due to the complex synthesis and low thermodynamic stability, the isolation of single phase 1T-MoS2 remains rather challenging. Contrastingly, polymorphic control of MoTe2 can be achieved by a simple change in synthetic temperature. Hence, the semiconducting and metallic phases can be easily isolated and therefore the effect of polymorphic control on catalytic activity can be accurately investigated in the bulk form. In this work, we exploit this facile polymorphic control and demonstrate that bulk 1T’-MoTe2 is an efficient electrocatalyst for the hydrogen evolution reaction with a Faradaic efficiency of 100 %. Therefore, we deem polymorphic control a key factor in the development of future HER catalysts.

Authors : Takuya NAKAO[1], Tomofumi TADA[2], Hideo HOSONO[1][2][3]
Affiliations : [1]Laboratory for Materials and Structures, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan; [2]Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8501, Japan; [3]ACCEL, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan

Resume : Recently, out group found that ruthenium (Ru)-loaded metal hydrides, such as Ca2NH, CaH2[1], LaH2 x, CeH2 x [2], works as efficient catalysts for ammonia synthesis under 0.1 MPa and 300-400 °C, which is milder reaction condition than Haber-Bosch process. The key points of the high activity using Ru/hydrides are the charge transfer from electron localized at surface hydrogen vacancy (VH) on hydrides to Ru and the reversible encapsulation of hydrogen adsorbed on Ru as H into the surface VH. Thus, the VH formation energy (Edef(VH)) at Ru/hydrides interface is a crucial factor in the VH-H exchange mechanism. The VH formation at Ru/hydrides interface is easier than that on pure hydride surfaces by the anti-bonding state between Ru and surface H. Thus, much easier formation of VH could be expected in other transition metal (TM) than in Ru, and Ru-TM intermetallic alloy-loaded hydrides possibly become more efficient catalyst for ammonia synthesis and other reactions. In this study, we investigated the VH formation at the Ru-TM/hydrides interface and the electronic structures of Ru-TM alloy by using Ru5TM/Ca2NH model with DFT calculations. We found that the Edef(VH)s decrease at a Ru5TM/Ca2NH interface compared with that at the Ru6/Ca2NH interface. At the conference, we will show the details of calculated Edef(VH)s of Ru5TM/Ca2NH interface and the correlation between the Edef(VH)s and TM-H covalent bonds. [1] M. Kitano et al., Chem. Sci. 7. 7 (2016): 4036-4043. [2] H. Mizoguchi et al., Inorg. Chem. 55.17 (2016): 8833-8838.

10:30 Coffee break    
Authors : Teahoon Park1, Kang Eun Lee1, Youngseok Oh1, Hanwhuy Lim2, Eunkyoung Kim2, Moon-Kwang Um1
Affiliations : 1. Carbon Composites Department, Korea Institute of Materials Science, Changwon, Korea (the Republic of). 2. Chemical and Biomolecular Engineering, Yonsei University, Seoul, Korea (the Republic of).

Resume : Conducting polymers (CPs) have unique properties, such as solution processability to create patterns on large areas, low processing costs for manufacturing devices, absorbing near infrared light, and application potential to flexible and light-weight devices. The PEDOT is a well-known CP. We can make this CP film by several polymerization techniques to obtain useful properties. Their doping level has been controlled and optimized by an electrochemical method to obtain high thermoelectric performances. Their conductive domain structure was controlled by a molecular structure organizer to achieve high enough conductivity for other electrical applications. Furthermore, the PEDOT film can convert photon to phonon energy through the photothermal effect. Therefore, the versatile PEDOT has been studied for thermoelectric, piezoelectric, pyroelectric, and hybrid energy applications. In addition, we tried to make practical devices using CPs. Several ideas were suggested by understanding different energy conversion mechanisms. A solar cell was combined with a pyroelectric and a thermoelectric device. The PEDOT film was fabricated for not only an electrode of pyroelectric film but the photothermal active layer. Combining these energy conversions, a new hybrid energy harvester was obtained which can operate electrochromic devices. We also tried to achieve a flexible thermoelectric device using CPs. Newly designed roll-type CP films were prepared and combined with n-type inorganic materials. For flexibility, a rigid-flexible concept was suggested and successfully achieved. With a handmade circuitry including connected capacitors, an LED was lit up by the rigid-flexible thermoelectric module.

Authors : Marcus D. Pohl(a), Federico Calle-Vallejo(b) and Aliaksandr S. Bandarenka(a)
Affiliations : (a) Technical University Munich, Department of physics, Working group ECS James-Franck-Str. 1, 85748 Garching b. München, Germany (b) Leiden University, Leiden Institute of Chemistry, PO box 9502, 2300 RA Leiden, Netherlands

Resume : The carbon monoxide oxidation (CMO) is an important reaction step limiting the efficiency of fuel cells based on the electrochemical oxidation of organic molecules like methanol, ethanol or dimethyl ether. Nowadays the State-of-the-Art catalysts for these fuel cells consist of the expensive precious metal platinum or its alloys. Therefore, the minimization of the catalyst loading is needed, while keeping the activity. This increase in efficiency calls for the identification of quantitative structure-activity relations. Unfortunately, these influences are generally assessed by demanding computational and experimental approaches. Alternatively, the so-called generalized coordination numbers (GCN) are a mathematically simple geometric descriptor. They link the activity of a catalytic site with their geometry by incorporating the coordination numbers of the neighboring atoms. This connection is illustrated in the so-called coordination-activity plot relating the geometry of surface sites with their activity for the CMO. In this talk, the legitimacy of GCN as descriptor is experimentally and theoretically proven for the CMO. Ultimately, allowing to determine the active sites for CO electro-oxidation based on simple and systematic coordination considerations.

Authors : K. Ebner, J. Herranz, T. J. Schmidt
Affiliations : Paul Scherrer Institut, Electrochemistry Laboratory, 5232 Villigen PSI, Switzerland ; Paul Scherrer Institut, Electrochemistry Laboratory, 5232 Villigen PSI, Switzerland ; Paul Scherrer Institut, Electrochemistry Laboratory, 5232 Villigen PSI, Switzerland & ETH Zürich, Laboratory of Physical Chemistry, 8093 Zürich, Switzerland

Resume : Polymer electrolyte fuel cells (PEFCs) are energy conversion devices well-suited for the automotive sector. To reduce their cost, efforts are made to employ materials based on abundant metals as the cathode catalyst [1]. Despite outstanding initial activities, widespread application of such non-noble metal catalysts (NNMCs) is hindered by their instability [2]. This is believed to be partially caused by the materials’ composition, which not only consists of active sites, but also of side phases that potentially catalyze side reactions and contribute to the depletion of active sites [3]. To gain insight into composition-related deactivation, a refined synthesis which offers precise composition control is imperative. With this in mind, we present a novel synthesis approach for Fe-based NNMCs where the influence of critical parameters on the composition is studied systematically. The obtained materials are characterized by means of electrochemical activity measurements (RDE and PEFC tests) as well as surface- and bulk-characterization techniques (N2-physisorption, transmission electron microscopy, X-ray photoelectron and absorption spectroscopy) allowing to correlate composition and electrochemical activity and durability, enabling fine-tuning of these crucial features. [1] Jaouen (2014), Non-Noble Metal Fuel Cell Catalysts, 29–118. [2] Shao et al (2016), Chem.Rev., 116(6), 3594–3657. [3] Banham et al (2015), J.Power Sources, 285, 334–348.

Authors : *Inyeong Kang(1,2), Juyoung Jang(1,2), Seong-In Kim(1), Kyung-Woo Yi(2), Young Whan Cho(1)
Affiliations : 1. High Temperature Energy Materials Research Center, Korea Institute of Science and Technology 2. Department of Materials Science and Engineering, Seoul National University

Resume : Several attempts have been made to solve the volumetric expansion problem of silicon anode materials, and their performance has been greatly improved. However, there are difficulties in practical use such as using expensive nano-silicon and complicated synthetic process. This study shows the results that can improve the performance of lithium ion batteries by introducing controllable void structure in silicon-based alloy anode materials. The active material that satisfies several solutions to solve disadvantages of silicon anode materials is synthesized with a simple and practical method. It is possible to reduce the absolute volume expansion of active materials by using ball-milled silicon/silicide nanocomposite. In addition, our approach is relatively easy to control both the size and volume fraction of voids using various size and volume fraction of water-soluble compounds. Also, the type of void structure can be controlled by changing the heat treatment condition. The microstructure analysis has shown the difference of void structure introduced into the active material. Coin half-cell tests demonstrate the improved electrochemical performance of the silicon/silicide nanocomposites with controllable voids compared to that of the anode materials without the voids. And different electrochemical behavior was observed depending on various void structures. In particular, the relationship between the size and amount of voids and the swelling of the electrodes has been analyzed quantitatively.

Authors : M. Zellmeier, M. Mews, and J. Rappich
Affiliations : Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institut für Silizium-Photovoltaik, Kekuléstr. 5, 12489 Berlin, Germany

Resume : Molecular doping of the organic semiconductor poly-(3-hexylthiophene), P3HT, with the strong molecular acceptor tetrafluorotetracyanoquinodimethane, F4TCNQ, is one of the most common techniques to overcome the restriction of low conductivity in this organic material. The well-established method leads to a decrease of the hole mobility in the low to medium doping regime, while the hole density increases linearly with the doping concentration [1]. Additionally, it presents an important prerequisite towards controlling p/n-junctions involving organic materials. Hybrid interfaces combining organic materials and inorganic semiconductors are of special importance as they are crucial for the performance of most applications, e.g. light emitting devices [2] or solar cells [3]. Employing photoelectron spectroscopy, we studied the interface between crystalline silicon, c-Si, and doped P3HT. The doping in the spin coated organic layer was varied from a low doping concentration of 1:1000 F4TCNQ molecules per 3HT monomer units up to 1:3. UPS was used to monitor the development of the HOMO-onset upon doping as well as the work function. A special focus is placed on the shift of the silicon 2p orbital binding energy, which is measured using XPS. The data is used to extract the band bending at the silicon/organic semiconductor junction. [1] P. Pingel et al., Appl. Phys. Lett. 100, 143303 (2012) [2] V. L. Colvin et al., Nature 370, 354 - 357 (1994) [3] M. Zellmeier et al., Appl. Phys. Lett. 107, 203301 (2015)

Authors : Amit Mahajan1,2*, Hangfeng Zhang 1, Haixue Yan1,2, and Mike J Reece1,2
Affiliations : 1 School of Engineering & Materials Science, Queen Mary University of London, Mile End Road, E1 4NS, London, United Kingdom 2 Nanoforce Technology Limited, London, Mile End Road, E1 4NS, London, United Kingdom

Resume : Relaxor-based ferroelectrics are looked as a potential material for pulsed power capacitors (energy storage) due to their high spontaneous polarization and low remanent polarization. By now, the maximum energy density was reported for the lead-based relaxor Pb0.92La0.08Zr0.52Ti0.48O3 in the form of a thin film (~ 11 J/cm3) and numbers for bulk ceramics are much lower (2.73 J/cm3). Due to lead toxic, there is a need for lead-free alternatives. One among other lead free ferroelectric is Bi0.5Na0.5TiO3 (BNT) – based compounds due to their high spontaneous polarization (> 30 µC/cm2) and due to weak polar phase (relaxor) above depolarization temperature. The depolarization temperature for BNT lies > 100 oC and can be shifted close to room temperature by A-site the substitution without compromising the spontaneous polarization. In this context, we have investigated the BNT – NaNbO3 compounds with A-site substitution with different mol. % of Li ions to achieve maximum energy storage density. The ceramics were fabricated using the solid state mixing route. The ceramics show relaxor ferroelectric loops at room temperature with energy density up to ~ 0.8 J/cm3 at 100 kV/cm with high efficiency >85 %, which can be attributed to the phase transitions produced by the chemical pressure that was induced by co-substitution on the A-site in BNT-based ceramics. The phase and microstructure of the ceramics were characterized using X – Ray diffraction (XRD) and Scanning Electron Microscopy (SEM), respectively. Piezo Force Microscope (PFM) was used to investigate the localized domains in the ceramics. The present studies emphasize that the BNT based compounds can be attractive candidate for lead-free high power energy storage applications.

12:30 Lunch break    
Authors : Tomás Palacios
Affiliations : Massachusetts Institute of Technology

Resume : Lateral GaN transistors are widely used today in state-of-the-art RF amplifiers and power electronics. However, in spite of the excellent results shown by these devices and their successful market penetration, their performance is still far from the theoretical maximum for GaN. The relatively low linearity, poor reproducibility of sub-100 nm gate length technology, and the high cost and difficulty of current ohmic regrowth technologies are important challenges of today’s lateral GaN RF devices. At the same time, the reliability, low current density and high device cost limits the penetration of GaN transistors in power electronics above 1000 V. This talk will describe how vertical GaN transistors could help overcome most of the challenges identified above for lateral GaN devices. For example, GaN vertical-fin FETs offer excellent performance as power switches with unprecedented current-density levels. When these transistors are fabricated on Si substrates, the cost is lower than in lateral devices and the performance is significantly improved. In addition, p-type ion implantation can be used to engineer the electric field, reduce leakage current and increase the breakdown. Approaches to scale-down these devices to sub-20 nm gate lengths, including hybrid Graphene/GaN hot electron transistor structures, will also be discussed, which open the door for vertical GaN to be used on advanced digital and mixed signal applications. Acknowledgements.- This work has been partially supported by the ONR PECASE program, monitored by Dr. Paul Maki, and by the ARPA-E Switches program, monitored by Dr. Timothy Heidel and Dr. Isik Kizilyalli.

Authors : Andréia Luísa da Rosa
Affiliations : Universidade Federal de Goiás Instituto de Física Campus Samambaia, Goiânia - GO, Brazil

Resume : Doping has been widely used to tailor the electronic, magnetic, and optical properties of semiconductors. Wide band-gap semiconductors such as ZnO are attractive for ultraviolet light-emitting diodes, lasers and high-power photonic applications. In ZnO, rare-earth elements can be incorporated in the material and the long lifetimes of the excited states allow for an easy realization of population inversion with promising applications in optoelectronics. The main challenge here is the correct description of both ZnO band edges and defect states. It is common understanding that the use of local exchange-correlation functionals wrongly described the ZnO band gap, which could lead to misleading conclusions on the location of the impurity rare-earth f states. Besides, intrinsic defects may also play an important role. In this work, the formation energies and electronic structure of rare-earth complexes in zinc oxide have been determined using density-functional theory and the many-body GW technique. In this talk we will discuss our results on complexes containing intrinsic defects and rare-earth elements in doped ZnO and the main challenges encountered to explain experimental spectra.

Authors : Louis Vaure,1 Liu Yu,2 Doris Cadavid,2 Dmitry Aldakov,1 Stéphanie Pouget,3 Andreu Cabot,2,4 Peter Reiss,1 Pascale Chenevier 1
Affiliations : 1 Univ. Grenoble Alpes, CEA, CNRS, INAC, SYMMES, 38000 Grenoble, France ; 2 IREC, Jardí de les Dones de Negre 1, Sant Adrià de Besòs, Barcelona 08930, Spain ; 3 Univ. Grenoble Alpes, CEA, INAC, MEM, 38000 Grenoble, France ; 4 Departament d’Electronica, Univ. de Barcelona, Barcelona 08028, Spain

Resume : Thanks to their robustness and simple design, thermoelectric generators are interesting candidates for microscale energy harvesting applications. However current room temperature thermoelectrics based on heavy elements such PbTe or Bi2Te3 would preferably be replaced by more abundant, eco-friendly and low cost materials for use in widespread applications such as internet of things. CuFeS2 is an interesting semi-conductor in this scope. It shows high Seebeck and easy doping affording good n-type conduction. The too high thermal conductivity in bulk can be reduced in nanostructured pellets from pressed nanopowders. Here we describe nanocomposites made of CuFeS2 colloidal nanocrystals. Grown in organic solvents, the nanocrystals present a surface/core gap in chemical composition that can be tuned by non-stoichiometric conditions in synthesis, or by post synthesis surface treatment of nanocrystals in solution. The nanocrystals are then mixed with Sn nanoparticles for additional surface doping and hot-pressed into pellets. The nanocomposite pellets show a 5 times decrease in thermal conductivity down to 0.8W/m/K compared to bulk chalcopyrite, while electrical conductivity is maintained above 50S/cm. Perspectives of improvements using anisotropic nanocrystals in the composites will be discussed.

Authors : F. Bouhjar, B.Marí and B. Bessaïs
Affiliations : a. Institut de Disseny i Fabricació, Universitat Politècnica de València. Camí de Vera s/n 46022 València (Spain) b. Laboratoire Photovoltaïques, Centre de Recherches et des Technologies de l’Energie Technopole H.lif 2050(Tunisia) c. University of Tunis

Resume : Polycrystalline Cr-doped hematite thin films have been successfully deposited on fluorine-doped tin oxide coated (FTO) glass substrates using the facile hydrothermal method. The hydrothermal bath consists of an aqueous solution containing a mixture of FeCl3.6H2O and NaNO3 adjusted to a pH = 1.5. The samples were introduced in an autoclave and heated for a fixed duration and temperature. Afterward, the hematite coated samples were annealed for a 4 h at 550°C. The Cr doping fractions were varied from 2 to 20 %. All samples were submitted to structural and morphological studies using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and High-resolution transmission electron microscopy (HRTEM). Cr doping induces a slight shift of the main diffraction peaks (012) and (104) towards lower angles. On the other hand, chronoamperometry technique showed that Cr-doped films exhibited higher photoelectrochemical activity relatively to un-doped α-Fe2O3 thin films. Maximum photocurrent densities as well as incident photon conversion efficiencies (IPCE) have been obtained for 16% Cr-doped films in a normal alcaline solution and under standard illumination conditions. We attributed this high photoactivity to the high active surface area of the nanostructured hematite and to the increasing donor density caused by Cr doping.

15:30 Coffee break    
Authors : Michal Wrzecionek [1], Grzegorz Matyszczak [1], Daniel J. Jastrzebski [1], Paulina Hubner - Kulicka [2], Jacek Ulanski [2], Slawomir Podsiadlo [1]
Affiliations : [1] Faculty of Chemistry, Warsaw University of Technology; Noakowskiego 3, 00-664 Warsaw, Poland [2] Department of Chemistry, Lodz University of Technology, Zeromskiego 116, 90-925, Lodz, Poland

Resume : The aim of this study was to obtain nanopowders with the structure of kesterite - Cu2ZnSnS4, Cu2CoSnS4, Cu2MnSnS4, Cu2NiSnS4. Then it was decided to create a prototype of photovoltaic cells based on received materials, because these compounds have semiconducting properties. Additionally, kesterite could be functionalized in a wide range by modifying the following variables: the ligand, the elements of the structure, the shape of nanoparticicles. This operation entails a modification of the width of the band gap and compatibility with semiconducting polymers used for the construction of solar cells. All this leads to a conclusion that kesterites are promising materials for applications in the field of photovoltaics. In the implementation of engineering work, nanopowders were obtained from metal chlorides and sulphur in organic solvent – oleylamine. Photovoltaic cells were made by application of respective layers by spincoating method. The study used the following test methods: X-ray powder diffraction, spectrophotometry UV-Vis, transmission electron microscopy, dynamic light scattering, current-voltage characteristics of the working of the photovoltaic cell.

Authors : Yeon Jun Choi, Hyun-Kyung Kim, Suk-Woo Lee, Hee-Chang Youn, and Kwang-Bum Kim e-mail :
Affiliations : Department of Material Science and Engineering, Yonsei University, 134 Shinchon-dong, Seodaemoon-gu, Seoul, 120-749, South Korea

Resume : Graphene has been studied as promising electrode material for supercapacitor owing to its large theoretical specific surface area (SSA) and high electrical conductivity. Ideal graphene has a theoretical SSA of 2650 m2/g, which is entirely from its basal plane. According to the theoretical SSA, a theoretical specific capacitance of ideal graphene is 530 F/g. However, specific capacitance of graphene is reportedly around 200 F/g, which is far below the theoretical specific capacitance of ideal graphene. Recent advances in introducing edge sites to the basal plane of graphene open up new ways to improve the specific capacitance of graphene. However, likewise 2D graphene, GNMs also have natural tendency to stack into multilayers, resulting in a decrease of the ion-accessible area and impeding in-plane ion diffusion. In this study, we report the fabrication of GNM/CNT composite by controlling the surface charge of CNTs, followed by catalytic carbon gasification. Incorporation of CNTs into GNM as nanospacers not only increased the ion-accessible surface area of GNM but also improved in-plane ion diffusion. Finally, the resulting GNM/CNT composite exhibited an outstanding electrochemical performance with a high specific capacitance (288 F/g at 0.5 A/g) and rate capability as well as excellent cycling stability (99% capacitance retention even after 30,000 charge/discharge cycles). More details will be discussed at the meeting.

Authors : Juyoung Jang(1,2), Inyeong Kang(1,2), Seong-In Kim(1), Kyung-Woo Yi(2), Young Whan Cho(1),
Affiliations : (1)High Temperature Energy Materials Research Center, Korea Institute of Science and Technology; (2)Department of Materials Science and Engineering, Seoul National University

Resume : The heat treatment process is essential to coat Si-based anode materials with carbon to enhance their electrical conductivity in lithium ion batteries. Although there are numerous previous works on carbon coating of silicon anode by various heat treatments, there is little study on the change in the active material itself. So, we focused on the change of active materials itself without coating layer. Si/iron silicide nanocomposite is prepared as anode materials in which electrochemically inactive iron silicide can serve as a buffer when active Si undergoes huge volume change during cycling. In this composite anode, there are two major changes after the heat treatment; phase transformation of iron silicide and grain growth of both Si and silicide. These factors can have significant influence on the electrical conductivity of the electrode. The effect of phase transformation between conducting α-FeSi2 and semiconducting β-FeSi2 phase on electrical conductivity of the composite anode will be presented. The microstructure change mainly due to grain growth of silicon and iron silicide will also be characterized by Rietveld refinement and TEM analysis.

Authors : Heechul Jung, Gyusung Kim, Sungsoo Han
Affiliations : Energy Lab., Samsung Advanced Institute of Technology, Suwon, Korea

Resume : To employ Li-based batteries to their full potential in a wide range of energy-storage applications, their capacity and performance stability must be improved. Si is a viable anode material for Li-based batteries in electric vehicles due to its high theoretical capacity and good economic feasibility. However, it suffers from physical and chemical degradation, leading to unstable electrochemical performance and preventing its incorporation in new Li-based battery systems. Herein, we applied a protective coating for Si-graphite anodes with hybrid polymer and confirmed an improvement in the electrochemical performance. The experimental results revealed that the polymer acts as a protective layer such as artificial SEI layer as well as a binder to alleviate the pulverization of the electrode. Furthermore, the oxide coating reduces the consumption of irreversible Li ion due to the formation of a stable solid electrolyte interphase. Our findings suggest that a stable and ion-conducting anode/interphase can be developed by applying an oxide and polymer coating in combined approach. Therefore, this study is expected to provide a basis for the further development and design of high-performance Li-based battery systems. After surface treatment with hybrid polymer, the capacity retention was improved compared with that of the bare electrode, and it shows a stable Coulombic efficiency through 100 cycles. We showed that electrode surface treatment can act as an artificial SEI, alleviating the pulverization of the electrode. In addition, it contributes to maintaining stable Li2O, which has high ionic conductivity, during repeated operation, resulting in the formation of a stable SEI layer. Furthermore, electrode surface treatment reduces the penetration of the electrolyte and suppresses the formation of reaction products inside the electrode. We believe that these results provide a deeper understanding of the effect of surface treatments on the formation of a stable and highly ion-conducting SEI layer and indicate its crucial role in electrochemical performance. Therefore, this study is expected to provide a foundation for the further development and design of high-performance LIBs.

Authors : Matthias Kuenzel, Dominic Bresser, Stefano Passerini
Affiliations : Helmholtz Institute Ulm (HIU), Helmholtzstrasse 11, 89081 Ulm, Germany Karlsruhe Institute of Technology (KIT), P.O. Box 3640, 76021 Karlsruhe, Germany ; Helmholtz Institute Ulm (HIU), Helmholtzstrasse 11, 89081 Ulm, Germany Karlsruhe Institute of Technology (KIT), P.O. Box 3640, 76021 Karlsruhe, Germany ; Helmholtz Institute Ulm (HIU), Helmholtzstrasse 11, 89081 Ulm, Germany Karlsruhe Institute of Technology (KIT), P.O. Box 3640, 76021 Karlsruhe, Germany

Resume : Given the rapid growth of the lithium-ion battery market, which is expected to gain even more momentum with the mass market introduction of electric vehicles in near future, it appears of utmost importance to improve their environmental benignity and sustainability.[1] In this regard, one of the great remaining challenges is the replacement of toxic and costly N-methylpyrrolidone, i.e., the positive electrode processing solvent, ideally by water and the introduction of cobalt-free active materials, since this metal has been identified as a highly critical element.[2,3] While the implementation of the high-voltage LiNi0.5Mn1.5O4 (LNMO) spinel provides a promising strategy in the latter regard, the aqueous electrode processing of lithium-ion cathodes is still a great challenge, due to the severe issues of lithium leaching and aluminum current collector corrosion, leading to immediate capacity loss, electrode degradation, and inferior cycling performance.[4] Herein, we present our recent successful implementation of aqueous electrode preparation techniques for high-voltage LNMO lithium-ion cathodes by identifying advanced binding agents and in situ surface coating techniques, allowing for an improved stabilization of the active material particles towards water. In particular, the combination of these complementary approaches results in a substantially enhanced performance without requiring any additional processing step.

Authors : Loay Elalfy, Dr. Yang Han, Prof. Dr. Ming Hu.
Affiliations : Institute of Mineral Engineering, Department of Materials Modeling, RWTH Aachen University. Mauerstr. 5, D-52064 Aachen, Germany

Resume : Thermoelectricity is the phenomenon of conversion temperature gradient into electric current and vice versa. This phenomena is becoming more important as it reduces the losses during energy conversion, mainly due to heat. The figure of merit (ZT) for thermoelectric materials is the quantity that reflects how efficient a material is. ZT is inversely proportional to the thermal conductivity, which means that for a better thermoelectric material, low thermal conductivity is to be achieved. For most of materials thermal conductivity increases under compression. However, recent study found that materials with negative Grüneisen parameter (negative thermal expansion materials) have the opposite effect [Physical Review B 92, 235204 (2015)]. The effect of pressure on thermal conductivity of zinc and cadmium telluride and antimonide was calculated by solving the Boltzmann transport equation using second- and third-order force constants calculated from Density Functional Theory. The contribution of mean free path, group velocities, and heat capacity on the thermal conductivity was revealed. For higher accuracy, time domain normal mode analysis was conducted to characterize the contribution from higher order phonon anharmonicity. The results show that the significant drop in the lattice thermal conductivity of the studied materials under pressure is mainly due to mean free path. Further underlying mechanism is analyzed and provided.


Symposium organizers
Manickam MINAKSHIMurdoch University

School of Engineering and Information - Technology, Murdoch, WA 6150, Australia
Rajeev AHUJADepartment of Physics and Astronomy, Uppsala University

Box-516 SE-75120 Uppsala, Sweden
Yong-Mook KANGDongguk University

Dept. of Energy & Materials Engineering - 30, Pildong-ro 1 gil, Jung-gu, Seoul, 04620, Republic of Korea

82 10 3257 9051