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Materials for a sustainable transition


Breakthrough zero-emissions energy storage and conversion technologies for carbon-neutrality

This symposium targets to attract novel concepts and breakthrough materials and technologies of storage and conversion of clean energy beyond batteries, solar cells and fuels with zero emissions of greenhouse gasses and a minimal use of rare or toxic materials.


The provision of clean and sustainable energy is a major target and challenge for Europe’s climate ambition. Towards this aim novel concepts and breakthrough techniques with zero emissions of greenhouse gasses and a minimal use of rare or toxic materials are required. Novel solutions for portable uses, in sustainable housing, remote places or in emergency situations that substitute fossil fuels are targeted.

This symposium focusses on breakthroughs in energy storage and conversion that is clean, compact and ultimately low-cost going beyond batteries, solar cells and fuels. Topics of interest could include solar fuels and chemicals, trasforming of atmospheric CO2 and other pollutants, method for efficiently converting waste heat and vibrations into electricity, optically controlled solar energy storage solutions, or novel thin-film technologies for energy storage. We will attract scientists with multidisciplinary research who will present advances in their material’s design, characterization, device fabrication and device performance. Circular design and focus on recyclability is desired.

This symposium is inspired by the FET Proactive call emerging paradigms and communities: Breakthrough zero-emissions energy storage and conversion technologies for carbon-neutrality.

Hot topics to be covered by the symposium:

  • Solar fuels and solar chemicals
  • Solid Oxide Fuel and Electrolysis Cells
  • Recycling of atmospheric CO2 and other pollutants
  • Method for efficiently converting waste heat and vibrations into electricity
  • Optically controlled solar energy storage solutions
  • Novel thin-film technology for energy storage
  • Operando characterization technique applied to energy and sustainability
  • Advanced materials for energy production and storage

List of confirmed invited speakers:

  • David Fairen-Jimenez (University of Cambridge, UK)
  • Magda Titirici (Imperial College, London, UK)
  • Esther Alarcón Lladó (AMOLF, Amsterdam, NL)
  • Mónica Burriel (CNRS, FR)
  • Felix Gunkel, (Forschungszentrum Jülich, DE)
  • Jin-Chong Tan (University of Oxford, UK)
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Electrochemical Energy Storage : Teresa Gatti
Authors : Magda Titirici, Heather Au, Maria Crespo, Hui Luo, Angus Pedersen,
Affiliations : Imperial College London

Resume : I will present my latest results on biomass electrooxidation to high value chemicals along with CO2 electroreduction to fuels and chemicals.

Authors : Minghao Yu, Xinliang Feng
Affiliations : Faculty of Chemistry and Food Chemistry & Center for Advancing Electronics Dresden (cfaed), Technische Universität Dresden, 01062 Dresden, Germany

Resume : Electrochemical energy storage technologies have been brought into the spotlight as they provide elegant and efficient approaches to storing, transporting, and delivering energy harvested from sustainable energy resources.[1-2] Typically, supercapacitors and batteries differ in electrochemical mechanisms, hence featuring almost opposite energy and power characteristics. However, the demand for power and energy supply is equally imperative in actual use and is keen to expand in the future. Thus it is highly desirable to design new electrode chemistries for energy storage devices to mitigate the power-energy tradeoff. Here, I will present our recent studies in controlling the charge carrier ions of 2D layered electrode materials for high-power energy storage applications.[3-5] Specifically, we have demonstrated several interlayer space engineering strategies for inorganic 2D layered materials to regulate the ion transport phenomena, such as solid-state diffusion kinetics,[6] selective-ion transport properties[7], and additional ion-storage sites[8]. Moreover, we will also introduce our latest efforts in manipulating interfacial ion behaviours (e.g., ion desolvation, anion-cation dissociation), by the manner of constructing crystal polymer-based artificial interface and precisely electrolyte engineering.[9-10] References: 1. Yu et al., Chem. Soc. Rev., 50, (2021) 2388-2443. 2. Yu et al., Joule, 3, (2019) 338-360. 3. Yu et al., J. Am. Chem. Soc., 142, (2020) 12903-12915. 4. Yu et al., J. Mater. Chem. A, 9, (2021) 19317-19345. 5. Yu et al., Mater. Chem. Front., 5, (2021) 2996-3020. 6. Yu et al., Nat. Commun., 11, (2020) 1348. 7. Yu et al., Angew. Chem. Int. Ed., 60, (2021) 896-903. 8. Yu et al., Adv. Mater., (2022) e2108682. 9. Yu et al., Small Science, 2, (2022) 2100080. 10. Yu et al., Adv. Mater., 32, (2020) e2000287.

Authors : Matteo Crisci1, Sara Domenici1-2, Jonas Pflug,1 Felix Boll1, Teresa Gatti1
Affiliations : 1Center for Materials Research, Justus Liebig University, Heinrich-Buff-Ring 17, 35392 Giessen, Germany 2 Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy

Resume : Wearable technologies will be the next frontier for device applications: they have been used for years, but the next step in this field would be to exploit these devices to both store and fuel the different individual daily necessities.[1] In order to do so, flexible and not-dangerous materials, that can achieve the highest performance possible without being degraded by daily usage and unusual deformation, are needed. For this reason, gels and, more specifically, conductive polymer hydrogels (CHPs)[2] are a very interesting class of material that allows to bridge the gap between electronics and the flexibility necessary to be used in wearable devices, while featuring good biocompatibility. Here, we report on the synthesis of hybrid CHPs based polyaniline (PANI) and 2D transition metal dichalcogenides (TMDCs), employing different methodologies and formulations. In particular, we resort to liquid phase exfoliation (LPE) to produce 2D TMDCs in both the 2H and 1T phase and to in-situ polymerization to produce PANI chains directly on the surface of these nanomaterials. Further morphology tuning is achieved by employing templating agents, being some of them also suitable to induce gelation. The as-obtained hydrogels are characterized through a combination of techniques and their swelling behavior and mechanical properties are investigated. Finally, they are integrated into proof-of-concept energy storage devices, to understand their potential for future use within flexible and wearable technologies. [1] Sumboja, A. et al., Chem. Soc. Rev., (2018), 47, 5919. [2] Stejskal, J. et al., Conducting polymer hydrogels. Chem. Pap., (2017) 71, 269–291. [3] Backes, C. et al., Chem. Mater. (2017), 29, 1, 243–255.

Authors : BENOÎT NOTREDAME*, Jean-François GOHY
Affiliations : UCLouvain – IMCN - BSMA 1, Place Louis Pasteur, 1348 Louvain-la-Neuve

Resume : Nowadays, commercial lithium-ion batteries are fabricated with electrodes separated by a flammable electrolyte based on organic solvents. Unfortunately, liquid electrolytes can lead to fire issues, explosion of the batteries and the resulting batteries cannot operate at a high voltage.[1] Therefore, new generations of safer batteries are under development. Among them, lithium metal batteries (LMBs) incorporating a solid-state electrolyte and a lithium metal anode are investigated. One of the major issues in LMBs is the ionic conductivity at room temperature of the solid electrolyte.[2] Furthermore those new solid electrolytes should be stable in a large electrochemical window. In this context, we are developing novel solid polymer electrolytes derived from a phosphonate monomer. Radical polymerization (RAFT or free) is used to prepare well-defined statistical copolymers containing phosphonate (MAPC1), cyclocarbonate (MA-cyCB) and boronate-containing (BPEGMA) monomers. This combination allows us to combine the flammability resistance and conductivity of phosphonate and the conductivity of cyclocarbonate groups when mixed with lithium salts (LiTFSI) with the addition of boronate flexibility to obtain a self-standing solid electrolyte. Ionic conductivities obtained at room temperature for those copolymers are in the same range as typical solid polymeric electrolyte not based on poly(ethylene oxide) (10-5 S/cm) and these electrolytes are stable in a large electrochemical window (0,5-6V vs Li+/Li) and until high temperature (>120°c). Furthermore, the addition of inorganic conductor particles (Li7-2xLa3Zr2-xWwO12, LLZWO) to enhance the conductivity as well the difference between copolymer and mix of homopolymers electrolytes has been investigated. References : [1] Q. Wang, C. Chen, Journal of Power sources, 208 (2012) 210-224 [2] H. Xiangming, W. Shuailing, Internation Journal of Mining Science and Technology, 23 (2013), 13-20

10:30 COFFEE BREAK    
Authors : David Fairen-Jimenez
Affiliations : The Adsorption & Advanced Materials Laboratory (A2ML), Department of Chemical Engineering & Biotechnology, University of Cambridge, Cambridge, UK.

Resume : The building-block approach to the synthesis of metal-organic frameworks (MOFs) has opened the possibility to synthesise a virtually infinite number of these materials. This creates exciting opportunities, but also raise the question of how to identify and classify MOFs among the plethora of existing crystal structures. At the same time, experimental trial-and-error discovery of MOFs is not fast enough and therefore new methods accessible not only to computational researchers but mainly to experimentalists need to be developed. To solve this problem, we have developed a curated database containing all the MOFs deposited in the Cambridge Structural Database (CSD). This initiative provides the MOF community with tools to extract their desired structures from the pool of crystalline structures in the CSD and to visualise their data of interest. We also developed new capabilities to enable researchers to browse and look for MOF families based on metal-clusters, chirality, surface chemistry (functional groups) and pore and network dimensionality. This has resulted in a regularly updated CSD-MOF subset of ca. 90,000 structures to date. With this tool, we have also demonstrated the power of the MOF subset for computational high-throughput screening (HTS), where we analyse their performance in different applications. We have completed the full cycle from the screening of MOFs to the identification and synthesis of optimal materials. To move it further, we have advanced on the shaping of MOF materials and in particular on porous, monolithic MOFs based on a sol-gel process without requiring binders and/or high pressures. The monolithic materials are able to retain the characteristic structure and porosity of the powders while showing a three times higher density and therefore three times higher volumetric gas adsorption capacity. This has resulted in some of the highest values reported to date for natural gas adsorption and carbon capture for conformed shaped porous solids. All in all, we believe this represents a significant step forward in the shaping and densification of MOFs, opening the gate towards their applicability in real-world industrial applications where high volumetric adsorption capacities and resilient mechanical properties are critical. Chem. Mater. 2017, 29, 7, 2618–2625 Chem. Sci. 2020, 11, 8373–8387 Nature Communications 2018, 9, 1378 Nature Materials 2018, 17, 174–179 J. Am. Chem. Soc. 2020, 142, 19, 8541–8549

Mechanical and Thermal Energy : Magda Titirici
Authors : Eder Amayuelas1*, Josh David Littlefair2, Luis Bartolomé1, Sandeep Kumar Sharma3,4, Jaideep Mor3, Pranav Utpalla3, Paweł Zajdel6, Yaroslav Grosu1,7
Affiliations : 1 Centre for Cooperative Research on Alternative Energies (CIC energiGUNE), Basque Research and Technology Alliance (BRTA), Alava Technology Park, Albert Einstein 48, 01510 Vitoria-Gasteiz, Spain. 2 Dipartimento di Scienze Chimiche, Farmaceutiche e Agrarie (DOCPAS), Università degli Studi di Ferrara (Unife), Via Luigi Borsari 46, I-44121, Ferrara, Italy. 3 Radiochemistry Division, Bhabha Atomic Research Centre Mumbai, India 400 085 4 Homi Bhabha National Institute, Anushaktinagar, Mumbai 400 094 6 Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500, Chorzow, Poland. 7 Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice, Poland.

Resume : Metal-organic frameworks are a well-known materials due to their proven capabilities in areas of industrial interest such as catalysis, biomedicine and gas adsorption and separation.[1] Moreover, in the last years hydrophobic MOFs became emerging materials in the field of energy dissipation.[2] By means of intruding water under pressure into MOFs’ hydrophobic porous structure and due to their outstanding features as the wide range of topologies, high surface areas and structural flexibility, these materials arise as great candidates for energetic applications such as shock-absorbers,[3] or as recently demonstrated, for the transformation of mechanical energy into electricity.[4] In this context, few MOFs were reported to show water intrusion-extrusion cycle, where ZIF-8 has turned out to be one of the reference MOFs in this field letting us to unravel the mechanism of intrusion and extrusion in these materials.[5] The well-known structural flexibility of this material, due to accommodation of the imidazolates at the pore gates when hosting guest molecules, lie beneath the shock absorber performance of ZIF-8. In this work we explore the impact of flexibility studying the water intrusion-extrusion performance of a stiffened ZIF-8_Cm. In this material, “pore gate opening effect” of imidazolates is limited due to suppressed linker mobility (and the pore diameter has been slightly enlarged) and, consequently, intrusion and extrusion pressures have been increased. We tackled the mechanism and the effect of stiffness by means of experimental water intrusion-extrusion measurements and atomistic simulations showing that structural properties such as flexibility/stiffness can be used for tuning intrusion-extrusion pressure. References [1] M. Safaei, M. M. Foroughi, N. Ebrahimpoor, S. Jahani, A. Omidi, M. Khatami, TrAC Trends in Analytical Chemistry 2019, 118, 401–425. [2] A. le Donne, A. Tinti, E. Amayuelas, H. K. Kashyap, G. Camisasca, R. C. Remsing, R. Roth, Y. Grosu, S. Meloni, 2022, 7, 2052353. [3] I. Khay, G. Chaplais, H. Nouali, G. Ortiz, C. Marichal, J. Patarin, Dalton Transactions 2016, 45, 4392–4400. [4] Y. Grosu, M. Mierzwa, V. A. Eroshenko, S. Pawlus, M. Chorazewski, J. M. Nedelec, J. P. E. Grolier, ACS Applied Materials and Interfaces 2017, 9, 7044–7049. [5] I. Khay, G. Chaplais, H. Nouali, C. Marichal, J. Patarin, RSC Advances 2015, 5, 31514–31518. Aknowledgment This project leading to this application has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101017858.

Authors : Louis L. De Taeye, Liese B. Hubrechtsen, Philippe M. Vereecken
Affiliations : Imec - Kapeldreef 75, Leuven, 3001, Belgium; KU-Leuven Centre for Membrane Separations, Adsorption, Catalysis, and Spectroscopy for Sustainable Solutions - Celestijnenlaan 200F - box 2454, Leuven, 3001, Belgium

Resume : A primary issue with remote sensor networks for IoT is the devices’ limited battery lifetime. Energy harvesting, wherein energy is harvested from the device’s surroundings and converted to electrical energy provides a more reliable source of energy for these devices. Energy can be harvested from a variety of sources, such as vibrations, photons, and temperature gradients. In this work, we focus on energy harvesting from temperature fluctuations using thermally regenerative electrochemical cycles (TREC). The TREC principle consists of charging and discharging an electrochemical cell at different temperatures. By combining two active materials with different thermogalvanic coefficients in a single cell, the discharge potential can be increased beyond the charge potential by this change in temperature, allowing thermal energy to be converted to electrical energy. The harvested energy can be stored in a stable manner with high cycle ability by using a Li-ion battery cell as both an energy harvester and storage device. Thin-film batteries are particularly well suited for this application, as this device will quickly reach the stable temperature, will comprise no thermal gradients and has a higher energy density due to the absence of inactive materials. In this work, we studied a selection of three active materials, namely LiFePO4 (LFP), Li4Ti5O12 (LTO), and LiMn2O4 (LMO). These materials are already in commercial use and comprise only abundant materials. A custom-built measurement set-up, capable of precisely measuring the thermogalvanic coefficient of individual active materials at different states of charge was used to study the three materials. In this presentation, we will showcase the dependence of the thermogalvanic coefficient on both the choice of active materials and the state of charge of the active material measured using this unique set-up. Further, general design principles for a Li-ion based TREC cell are derived from the material analyses, which can be used to guide the choice of material for full TREC cells. Three material properties of importance for active materials for TREC devices will be elucidated: (1) the thermogalvanic coefficient of the full cell has to be sufficiently high to harvest energy from limited temperature changes, (2) the thermogalvanic coefficient has to be nearly constant over the entire insertion region of the active materials to avoid a diverging harvesting loop, and (3) the voltage hysteresis of the active material has to be limited to enable harvesting.

Authors : Andrea Le Donne, Alexander Lowe, Miroslaw Chorazewski, Yaroslav Grosu, Simone Meloni
Affiliations : Dipartimento di Scienze Chimiche, Farmaceutiche e Agrarie (DOPAS), Università degli Studi di Ferrara (Unife), Ferrara, Italy; Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice, Poland; Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice, Poland; Centre for Cooperative Research on Alternative Energies (CIC energiGUNE), Basque Research and Technology Alliance (BRTA), Alava Technology Park, Albert Einstein 48, 01510 Vitoria-Gasteiz, Spain; Dipartimento di Scienze Chimiche, Farmaceutiche e Agrarie (DOPAS), Università degli Studi di Ferrara (Unife), Ferrara, Italy

Resume : Intrusion and extrusion processes of a liquid into a porous material are important for many technological applications, among which the separation of liquids1, conversion and storage of energy2-3, porosimetry, biological and bioinspired channels4, and others. Intrusion/extrusion of solutions and liquid mixtures are relevant to both separation and energy storage. For example, water-salt solutions might allow to increase the intrusion pressure of porous materials and, hence, mechanical energy that can be stored through this process5. However, salts might be aggressive and deteriorate materials used to build devices. Here we consider the alternative strategy of using alcohol/water solutions for the same purpose. In particular, we focus on alcohol/water solutions intruding/extruding ZIF-8, a prototypical hydrophobic metal-organic framework. If alcohol molecules are too large to intrude inside ZIF-8, the process is accompanied by a water-alcohol/water solution demixing, which could represent a possible method to increase the heat of intrusion and to exploit the heat of demixing. We focused on three different water/alcohol mixtures - methanol, tert-butanol and glycerol – and investigated intrusion/extrusion of water and alcohols. Several challenges arise for modelling the intrusion path for a system like these: during intrusion, water molecules must cross narrow pseudo-hexagonal windows, which represent a kinetic bottleneck of the process. Furthermore, the possibility that the alcohol molecules enter and stuck to the internal cavities of ZIF-8, preventing int/ext cycles, should be taken into account. We performed both “brute force” and enhanced sampling simulations (Restrained Molecular Dynamics and Parallel Replica Molecular Dynamics) of ZIF-8 slab in contact with the alcohol/water solutions to investigate intrusion/extrusion energetics and kinetics as well as the interface between alcohol/water mixtures and ZIF-8. 1. Yang H.-C., Hou J., Chen V., et al. Ang. Chem. Int. Ed. 2016, 55, 13398–13407. 2. Eroshenko V., Regis R.-C., Soulard M., et al. J. Am Chem Soc. 2001;123:8129–8130. 3. Grosu Y., Mierzwa M., Eroshenko V. A., et al. ACS Appl. Mater. Interfaces. 2017, 9, 7044–7049. 4. Gußmann F., Roth R. Phys. Rev. E 2017, 95, 062407. 5. Fraux G., Boutin A., Fuchs A. H., Coudert F.-X. J. Phys. Chem. C 2019, 123, 25, 15589–15598.

12:30 LUNCH BREAK    
Solar Energy Conversion (I) : Ilka Kriegel
Authors : Esther Alarcon-Llado
Affiliations : AMOLF

Resume : Nanostructured semiconductors and metals are promising building blocks for next generation solar energy conversion devices at low cost, including solar cells and solar fuel devices. From the optical perspective, nanostructure (NS) ensembles constitute a new class of metamaterial, where the optical properties (light absorption, transmission and scattering) of the ensemble are ruled by the NS geometry and collective arrangement. As an example, we have demonstrated that rationally designed NS offer new high efficiency solar cell designs that minimizes material usage (i.e. reduction of 99.9% of the material). Also, new additional functionalities are enabled, including a new kind of semi-transparent solar energy devices. Despite the great potential for such nanostructured architectures, there is still a major challenge in the field on nanoscale solar energy devices: how to cost-effectively fabricate large area NS arrays on a substrate. Electrochemistry offers an attractive manufacturing method through electrochemical deposition and etching for a wide range of materials owing to its inherent low cost, minimal raw material usage, low temperature budget and high throughput. Electrochemical deposition is an emerging powerful tool for NS fabrication. Electrochemically grown metal nanoparticle arrays have been demonstrated for a wide range of applications, and large area arrays with targeted light-matter interactions have been demonstrated by combining electrochemistry with a scalable patterning method. However, the arrays are typically polydisperse as little is known about local electrochemical environment effect on nucleation and growth at the single NS level. Here, we use in-situ electrochemical scanning probes as means to probe and control the electrochemical environment during electrochemical growth and dissolution. We demonstrate that SPM tips can confine metal deposition down to 50 nm around the tip offering a step forward towards 3D printing of metals and semiconductor nanostructures on demand. On the other hand, green electrical current from solar or wind energy is now comparable in cost to conventional sources, but the intermittency of the power generation makes energy storage crucial. Electrolyzers convert electricity directly into fuel through the formation of energy-rich compounds such as hydrogen, hydrocarbons or alcohols from water and CO2. Electrocatalysts serve to lower the activation energy. Unfortunately, the best electrocatalysts so far are based on precious metals such as platinum, thus hampering scalability. The field desperately looks for earth-abundant materials with similar catalytic properties. However, the key limiting factor in this quest is the lack of understanding of why this activation energy is different from one material to another, and even at different locations within the same material. To solve this, we are developing operando scanning probes and fluorescence microscopy to identify catalytic efficiency variations across the surface and correlate them to nanoscale irregularities, such as roughness, variations in crystal lattice structure, presence of crystal defects, etc.

Authors : Junya Kimura1,Erika Saito1,Midori Suzuki1,Tsukasa Yoshida1
Affiliations : 1:Yamagata university

Resume : Organic solar cells achieve efficient charge separation by creating a junction interface between donor (D) and acceptor (A) molecules in the light absorbing layer. At that time, a large voltage loss in the relaxation process from the Frenkel exciton to the charge transfer (CT) exciton is a problem. Therefore, we aim to construct a novel organic solar cell without voltage loss by using an organic charge-transfer complex as a single light-absorbing layer to generate CT exciton directly from light absorption. In our research, it was recently observed that the dianionic xanthene dye Eosin Y (EY) and the monocationic phenothiazine dye Methylene Blue (MB) quench each other in mixed aqueous solution. Considering the HOMO-LUMO level, the photoexcitation of EY probably causes electron transfer from EY to MB, and the photoexcitation of MB is thought to induce hole transfer from MB to EY, both of which are in the CT state. Co-salting of organic ions is a good strategy because the strong Coulomb interaction is expected to improve crystallinity and carrier mobility. The purpose of this study is to elucidate the crystal structure and exciton behavior in the solid state in order to investigate whether the newly discovered EY-MB CT pair can be applied as a single light absorbing layer in organic solar cells. EY-MB powder was obtained by precipitation of EY and MB at an amount of substance ratio of 1 : 2 in aqueous solution, and filtration. By dissolving the powder in an ethanol solvent with high affinity for EY-MB and comparing the absorbance, it was determined that EY : MB is a stoichiometric ratio of 1 : 2 based on charge balance. Absorption spectra of the powder show an increase in absorbance around 720 nm at the expense of the original absorption of MB, confirming photoexcitation to directly form the CT state. Emission spectra were measured after cooling down to 77 K to survey the exciton behavior in detail. In addition to the EY and MB-derived emission peaks, a luminescence not seen in the single molecule was observed around 900 nm. Excitation spectral measurements revealed a slight contribution of CT absorption. This indicates that the relaxation from Frenkel exciton generated inside the EY and MB molecules to CT exciton occurs in parallel with the direct generation of CT exciton. In addition to this fact, for application to novel solar cells, the conduction path of the carriers is necessary and the packing mode of the constituent molecules is important. Powder XRD measurements clarified new peaks that were not found in the single-component powder, which is considered to form a co-crystal. By creating single crystal of the dye pair, relationship between molecular orientation and intermolecular interactions will be discussed in more detail.

Authors : Fabian Schmitz,1,2 Nicolò Lago,3 Lucia Fagiolari,4 Julian Burkhart,1 Andrea Cester,3 Andrea Polo,3 Mirko Prato,5 Gaudenzio Meneghesso,3,6 Silvia Gross,6,7 Federico Bella,4 Francesco Lamberti,6,7 Teresa Gatti1,2
Affiliations : 1 Institute of Physical Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, 35392 Giessen, Germany 2 Center for Materials Research, Justus Liebig University, Heinrich-Buff-Ring 17, 35392 Giessen, Germany 3 Department of Information Engineering, University of Padova, Via Gradenigo 6/B, 35131 Padova, Italy 4 Department of Applied Science and Technology, Politecnico di Torino, Duca degli Abruzzi 24, 10129 Torino, Italy 5 Materials Characterization Facility, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genova, Italy 6 Center “Giorgio Levi Cases” for Energy Economics and Technology, Via Marzolo 9, 35131, Padova, Italy 7 Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy

Resume : Costs and toxicity concerns are at the center of a heated debate regarding the implementation of perovskite solar cells (PSCs) into commercial products. The first bottleneck could be overcome by eliminating the top metal electrode, generally gold, and the underlying hole transporting material and substituting both with one single thick layer of conductive carbon, as in the so-called carbon-based PSCs (C-PSCs). The second issue, related to the presence of lead, can be tackled by resorting to other perovskite structures based on less toxic metallic components. An interesting case is that of the double perovskite Cs2AgBiBr6, which at present still lacks the outstanding optoelectronic performances of the lead-based counterparts, but is very stable to environmental factors. In this contribution, we report on the processing of carbon electrodes onto Cs2AgBiBr6-based C-PSCs starting from an additive-free isopropanol ink of a carbon material obtained from the hydrothermal recycling of waste tires and employing a high-throughput ultrasonic spray coating method in normal environmental conditions. Through this highly sustainable approach, we obtain devices delivering record open circuit voltages of 1.293 V, which might in the future represent ultra-cheap solutions to power the indoor Internet of Things ecosystem.

Authors : Zijie Sha, Zonghao Shen, Eleonora Calì, John A. Kilner, and Stephen J. Skinner
Affiliations : Department of Materials, Exhibition Road, Imperial College London, London, SW7 2AZ, UK.

Resume : The ability of mixed ionic and electronic conducting (MIEC) perovskite oxides (ABO3) to support both electronic and ionic conductivity, as well as their favourable catalytic properties and chemical and redox stability, make them promising electrode materials in electrochemical energy conversion devices, such as solid oxide fuel/electrolysis cells (SOFC/SOEC) and oxygen transport membranes (OTM). In these applications, the exchange of oxygen across the gas phase and an electrode often determines the overall device performance, and the surface exchange kinetics have been found strongly related to the surface composition of electrodes. Currently, the nature of these electrode surfaces, particularly under the gas atmospheres closer to those experienced in operation, still remains unexplored. In this work, taking (La0.8Sr0.2)0.95Cr0.5Fe0.5O3-δ (LSCrF8255) as a model MIEC perovskite oxide, the surface composition evolution was studied under dry oxygen (pO2 = 200 mbar), wet oxygen (pO2 = 200 mbar, pH2O = 30 mbar), and water vapour (pO2 < 1 mbar, pH2O = 30 mbar) environments, to reflect the implementation of the materials for oxygen reduction/evolution and H2O electrolysis in the applications mentioned above. The surface chemistry and morphology of the materials were investigated comprehensively through X-ray photoelectron spectroscopy (XPS), angle-resolved XPS (ARXPS), low energy ion scattering (LEIS), scanning electron microscopy (SEM), and scanning transmission electron microscopy (STEM). The Sr surface segregation phenomenon has been observed on surface of all the samples annealed in dry oxygen, wet oxygen, and water vapour. The segregation level increased with annealing temperature, and was found particularly high at 900 °C. For the samples annealed at 900 °C in different atmospheres with the same 27-hour annealing time, the surface of the sample annealed in water vapour displayed the highest atomic fraction of Sr in surface species compared to Sr in the perovskite structure, however, the surface of the sample annealed in dry oxygen showed the highest total Sr content. Meanwhile, on the sample annealed in wet oxygen, Sr surface enrichment was likely suppressed. In addition, the Sr segregation phenomenon observed on LSCrF8255 can be correlated to other mass transport phenomena such as Cr evaporation and redeposition and Si deposition. Further, the Sr segregation behaviour on LSCrF8255 can also be related to annealing duration, crystal orientation, and defects such as grain boundaries and dislocations. Apart from the A-site cation segregation, a phase separation was consistently observed on all samples annealed in the three conditions. The secondary phase was B-site cation (relatively Cr enriched, significantly Fe enriched) enriched and A-site cation (La and Sr) deficient. In addition, in contrast to the Sr enriched surface, a La enriched surface was observed on samples annealed in dry oxygen at 600 and 700 °C, which was found to be potentially caused by the Sr and Cr surface evaporation processes. Our scientific findings are expected to provide an advancement in understanding and guidelines for material design, performance, and durability of MIEC perovskite oxide applications.

15:30 COFFEE BREAK    
Solid Oxide Cells : Alarcon-llado Esther
Authors : M. Burriel* (a), Alexander Stangl (a), Adeel Riaz (a,b), R. Rodriguez-Lamas (a), C. Pirovano (c), L. Rapenne (a), E. Sarigiannidou (a), D. Pla (a), O. Chaix-Pluchery (a), Michel Mermoux (b), R.-N. Vannier (c), and C. Jiménez (a)
Affiliations : (a) Univ. Grenoble Alpes, CNRS, Grenoble INP, LMGP, F-38000 Grenoble, France (b) Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, Grenoble INP, LEPMI, 38000 Grenoble, France (c) Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille, France

Resume : Ionic transport is of primary importance for the development and miniaturization of numerous devices such as solid oxide fuel cells and electrolyzers, oxygen separation membranes, and memristive devices. When prepared in the form of thin films, the functional properties can largely vary in comparison to the intrinsic bulk ones. There is thus a large interest in understanding and controlling the influence of parameters such as epitaxy, substrate-induced strain, and nano-structure, for the use of ionic conducting oxides in applied functional devices. Using Pulsed-Injection Metalorganic Chemical Vapor Deposition we have developed different strategies to control the growth of perovksite, and perovskite-related thin films, such as LaMnO3±δ and La2NiO4+δ. The oxygen stoichiometry, oxygen diffusion, and both the intrinsic and apparent oxygen exchange activity can be tailored in these thin films by tuning the deposition parameters, leading to differences in the amount of point and extended defects in the films, to different strain states, as well as to diverse controlled nano-architectures (dense, nano-columnar, nano-hierarchical). Ultimately by selecting the appropriate deposition conditions a substantial enhancement of the ionic transport properties in the films is achieved.

Authors : Juan de Dios Sirvent(a), Albert Carmona(a), Laetitia Rapenne(b), Francesco Chiabrera(a), Alex Morata(a), Mónica Burriel(b), Federico Baiutti(a,c), Albert Tarancón(a,d).
Affiliations : (a) Department of Advanced Materials for Energy, Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, Sant Adrià del Besòs, Barcelona 08930, Spain (b) Univ. Grenoble Alpes, CNRS, Grenoble INP, LMGP, 38000 Grenoble, France (c) Department of Materials Chemistry, National Institute of Chemistry, Hajdrihova 19, Ljubljana SI-1000, Slovenia (d) ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain

Resume : A paradigm shift will take place in the energy industry in the upcoming years, leading to the appearance of new technologies for feeding the power supply chain. Among these solutions, solid oxide cells (SOCs) are expected to play an important role for both storing and generating power on-demand in an efficient and sustainable manner. Nonetheless, limitations faced by these systems (e.g. high temperature operation, undesired side reactions and material degradation) must be solved. With this goal in mind, research on the fabrication of functional layers, to be implemented within the architecture of SOCs, is an appealing strategy particularly for avoiding the formation of secondary phases on the electrolyte-electrode interface and for preventing electrode degradation. In this work, we show results on fabrication and characterization of a series of thin film heterostructures (i.e. in-plane oriented multilayer and self-assembled nanocomposite) based on La0.75Sr0.25Cr0.5Mn0.5O3 (LSCrMn) and Ce0.8Sm0.2O2 (SDC), to be employed as functional layers in fuel electrodes and symmetrical systems. The two heterostructures present a dense, polycrystalline microstructure, with differentiated perovskite and fluorite-rich phases. In both cases a promising electrochemical performance under hydrogen atmosphere was obtained (ASR ≈10 Ω.cm2 at 750 ºC), while high in-plane conductivity -characteristic of the perovskite phase- was maintained. Most interestingly, the self-assembled LSCrMn-SDC nanocomposite also showed a remarkable electrochemical performance under oxidizing conditions, surpassing the activity of the rest of the materials studied and hence being suitable for use as a symmetrical functional layer in full cell devices. The electrochemical stability of this nanocomposite upon degradation at 780 ºC has been studied for over 500 h with no significant increase in the area specific resistance, leading to potential applications as robust electrodes in symmetric SOCs.

Authors : Brigita Abakevičienė, Fariza Kalyk, Tomas Tamulevičius, Sigitas Tamulevičius
Affiliations : Kaunas University of Technology, K. Donelaičio st. 73, LT-44249 Kaunas, Lithuania

Resume : The development of nanostructure cells, which cannot be achieved with ceramic processes, can be realized through the use of thin films, which can lower the solid oxide fuel cell (SOFC) operating temperature and improve their performance. Techniques using vapor deposition have, therefore, attracted significant amounts of attention for the fabrication of solid oxide thin films. The e-beam evaporation technique is initially used to melt down the target material using an electron beam, and the evaporated atoms are deposited onto the substrate. A dense film can, could be obtained via the use of a high deposition rate, and the quality of the thin film is excellent due to the process clean vacuum. The e-beam evaporation technique could be used for deposition of the thin film interlayers for SOFC. In this study, the 8 mol % yttria stabilized zirconia (8YSZ) thin films was deposited on different substrates and the physical properties were investigated. The chemical composition of evaporated 8YSZ thin films with different thicknesses up to 200 nm were obtained from SEM/EDX and ICP-OES analysis showed that the stoichiometry deviation of the evaporated thin films is, on average, 30 % lower than that of the target material. To control the chemical composition of YSZ thin films, the target materials should be prepared with higher stoichiometry using the chemical synthesis routes. In this study, the co-precipitation synthesis was used to produce the yttria stabilized zirconia as the target material with different stoichiometry.

Authors : Hyunjung Lim 1,2, Gwangsik Mun 1, Songhak Yoon 1, Marc Widenmeyer 2, Benjamin Balke 1, Anke Weidenkaff 1,2
Affiliations : 1 Fraunhofer Research Institution for Materials Recycling and Resource Strategies IWKS, Aschaffenburger Straße 121, 63457 Hanau, Germany 2 Technical University of Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt, Germany

Resume : The growing demand for conversion of clean energy has attracted much attention for many years to solid oxide fuel cells (SOFC), a promising power generation technology in view of efficient conversion of hydrogen and carbon monoxide at high operating temperature. One of the major challenges of developing SOFC is designing the cathode materials, which should have promising material properties including high ionic conductivity, electronic conductivity, and oxygen reduction reaction (ORR) activity. Mixed ionic-electronic conductors (MIEC) such as perovskite-type oxides La0.6Sr0.4CoO3–δ (LSC), and La0.6Sr0.4Co0.2Fe0.8O3–δ (LSCF) have been extensively investigated as cathode materials so far. Cobalt-based perovskite-type oxides have shown good electrochemical performance and catalytic activity as cathode in SOFC. [1] However, cobalt is regarded as one of the critical raw materials with high risk of supply. For sustainable and waste-free circular economy, implementation of clean and renewable technologies by substitution of critical raw materials by more sustainable alternatives has become an essential issue. In the present work, perovskite-type Sr- and Ni-substituted lanthanum ferrite for MIEC has been investigated expecting better oxygen reduction reaction activity compared with Co-based perovskites. [2] Three series of perovskite (La1–xSrx)(Fe1–yNiy)O3–δ (x = 0.1-0.2, y =1/7; x = 0.2-0.3, y =1/4; x = 0.28-0.38, y =1/3) powders were synthesized via solid-state reaction and further characterized by X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Le Bail fits of the XRD patterns of three series clearly showed linear decrease of unit cell volume with increasing Sr-substitution. Contraction of unit cell volume is attributed to the partial oxidation of Fe and/or Ni, resulting in the expected electrical conductivity enhancement. [3] Moreover, the change of the unit cell volume after thermal reduction showed same trend with the mass change in TGA. Evidently, a strong correlation between crystal structural changes and formation of oxygen vacancies with oxygen nonstoichiometry in (La1–xSrx)(Fe1–yNiy)O3–δ is highlighted in this study. In summary, substitution of trivalent La ion by divalent Sr ion can lead to the formation of either oxygen vacancies or electron holes to maintain the charge neutrality. [3] Both charge compensation mechanisms have been investigated more in depth trying to elucidate which mechanism is dominant. As an outlook, this approach would serve as a predictable indicator for comparing ionic and electronic conducting properties within varying compositions in cobalt-free (La1–xSrx)(Fe1–yNiy)O3–δ and will facilitate finding the potential cathode compositions for the final application in solid oxide cells. References [1] M. J. López-Robledo, et al., J. Power Sources 2018, 378, 184. [2] Y. Tian, et al., ACS Appl. Energy Mater. 2019, 2, 3297. [3] Q. Ji, et al., Energy Environ. Sci. 2020, 13, 1408.

Authors : Fjorelo Buzi (1), Kosova Kreka (1), José Santiso (2), Monica Burriel (3), Lucile Bernadet (1), Federico Baiutti (1), Albert Tarancón (1,4)
Affiliations : (1) Catalonia Institute for Energy Research (IREC), Jardins de Les Dones de Negre 1, 08930 Sant Adrià Besos, Barcelona, Spain; (2) Catalonia Institute for Nanoscience and Nanotechnology (ICN2), Campus de la Universitat Autònoma de Barcelona, Edifici ICN2, Av. de Serragalliners, s/n, 08193 Bellaterra, Barcelona; (3) Laboratories of Materials and Physical Engineering (LMGP) UMR 5628 CNRS, Grenoble INP Minatec 3, Parvis Louis Néel CS 50257 38016 GRENOBLE Cedex 1 France; (4) ICREA, Passeig Lluís Companys 23, Barcelona 08010, Spain

Resume : Thin-film engineering is a promising tool for next-generation solid oxide fuel cells (SOFCs) with improved energy conversion performance. Oxygen reduction reaction (ORR) at the air electrode has been widely reported to represent a bottleneck for the overall performance of SOFC devices. Hence, electrode material choice and optimization are crucial. While the introduction of mixed ionic-electronic conductors (MIECs) can significantly enhance the ORR activity and the final output of the cell, the intrinsic thermochemical instability of such materials during long term operation (around 700-900°C) hinders their wide deployment. To this end, nanoengineering of MIECs is a promising approach for tuning the electrochemical activity while suppressing detrimental structural evolution. In this work, perovskite-based nanocomposites of lanthanum strontium cobaltite (La1-xSrxCoO3 with x = 0.2, 0.4 - LSC) and samarium-doped ceria are directly synthesized via pulsed laser deposition (PLD) to be employed as a SOFC air electrode functional layer. Electrochemical characterization reveals high electrochemical activity towards ORR (ASR ≈ 1.2 cm-2 at 700 ºC) and, more importantly, outstanding long-term thermochemical stability (ASR degradation rate -20 vs +110 % for single phase LSC, as resulting from 100 hrs monitoring of ASR evolution at 700º C in open circuit conditions). These results will be discussed on the basis of a comprehensive system characterization, including impedance spectroscopy under polarization, high resolution X-ray diffraction, scanning and transmission electron microscopy, surface analysis by X-ray photoelectron spectroscopy.

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Electrocatalysis : Simone Meloni
Authors : Moritz Weber, Lisa Heymann, Anton Kaus, Marcus Wohlgemuth, Christoph Bäumer, Felix Gunkel
Affiliations : Peter Grünberg Institute, Forschungszentrum Jülich, Germany; MESA+ Institute, University of Twente, The Netherlands

Resume : Complex oxides have evolved as a major class of functional energy materials applied in a wide range of energy conversion and storage approaches which harvest the ability to precisely tailor and combine oxides on the nanoscale. Heterogeneous interfaces of oxides enable the exchange of ionic and electronic defect species between the neighboring materials, giving rise to electronic-ionic charge transfer and space charge formation.[1] Such space charge regions typically possess distinctly different material properties as compared to the bulk and allow tailoring and tuning of ionic-electronic properties by intentional design of interfaces. Here, we will discuss how dedicated design and understanding of interfacial space charge phenomena can be used to tailor electronic and ionic charge transport along and across electrochemically active oxide interfaces and surfaces, with particular focus on the role of space charge at solid-liquid interfaces operating in alkaline water splitting. We will discuss materials engineering strategies that allow to overcome the limitations of ‘bulk catalyst’ owing to intrinsic scaling relations and the typically observed inverse relationship of catalyst activity and long term stability. [2] As we elaborate the choice and combination of select oxides in from of defined multilayers and superlattices can lead to superior stability compared to the parent materials.[3] As will be discussed the dedicated control of the surface band structure of oxide catalysts via space charge can be used to mediate activity for oxygen evolution reaction, while the mass transport across the interface is responsible for the degradation and limited lifetime of the catalysts.[4] In this way, the control of space charge and electronic structure can be used to realize hybrid catalysts that attempt to break the classically inverse relations of electrochemical activity and stability. [1] Gunkel et al., J. Mater. Chem. (2020) [2] Wohlgemuth et al., Front. Chem. (2022) [3] Heymann et al., ACS Appl. Mater. Interf. (2022) [4] Weber et al., under review (2022)

Authors : Hakan Bildirir, Diego A. Alvan, Nagaraj Patil, Rebecca Grieco, Víctor A. de la Peña O´Shea, Marta Liras, Rebeca Marcilla
Affiliations : Hakan Bildirir 1,2; Diego A. Alvan 1; Nagaraj Patil 1; Rebecca Grieco 1; Víctor A. de la Peña O´Shea 2; Marta Liras 2; Rebeca Marcilla 1 1 Electrochemical processes Unit, IMDEA Energy, Mostoles/Spain 2 Photoactivated Processes Unit, IMDEA Energy, Mostoles/Spain

Resume : Porous organic polymers provide high dimensionality and high surface areas, which make them favorable for many applications from separation to organic electronics.[1–3] To form porosity along a polymeric skeleton, it is necessary to use angled and rigid (co)monomers, which are also called as structure directing motives. The restricted packing of such building blocks results in empty voids (i.e. pores) along the backbone, hence the high accessible surface areas. Even though the high surface area and dimensionality make porous organic polymers very attractive, a task-specific design for the planned usage area is necessary for a successful outcome.[4] For example, the materials produced from carbonyl bearing monomers (e.g. anthraquinone) demonstrate significant performances for battery applications[5] whereas the ones containing thiophene derivatives (e.g. dibenzothiophene S,S dioxides) are highly efficient for photocatalytic hydrogen evolution (HER).[6] In this communication, the delicate points of task-specific porous polymer synthesis for energy storage applications will be highlighted. Briefly, investigations regarding to the combinations of various redox-active compounds in porous polymeric backbones will be presented. Effect of the ratios of co-monomers exhibiting different redox properties to the overall electrochemical performances and post-modifications to the processability (e.g. post-synthetic miniemulsion hydrothermal treatment) will be discussed. Acknowledgement: Authors acknowledge the funding support given by the Spanish Ministry of Science and Innovation (MCIN/AEI/10.13039/501100011033) through the SUSBAT project (Ref.RTI2018-101049-B-I00) and the Maria de Maetzu Unit of Excellence award (Ref: CEX2019-000931-M) and by the European Union’s Horizon 2020 under the Marie Skłodowska-Curie grant agreement (No 860403). References [1] N. Chaoui, M. Trunk, R. Dawson, J. Schmidt, A. Thomas, Chem. Soc. Rev. 2017, 46, 3302–3321. [2] H. Bildirir, V. G. Gregoriou, A. Avgeropoulos, U. Scherf, C. L. Chochos, Mater. Horizons 2017, 4, 546–556. [3] H. Bildirir, Crystals 2021, 11, 762. [4] Q. Sun, Z. Dai, X. Meng, L. Wang, F. S. Xiao, ACS Catal. 2015, 5, 4556–4567. [5] A. Molina, N. Patil, E. Ventosa, M. Liras, J. Palma, R. Marcilla, Adv. Funct. Mater. 2020, 30, 1908074. [6] M. Sachs, R. S. Sprick, D. Pearce, S. A. J. Hillman, A. Monti, A. A. Y. Guilbert, N. J. Brownbill, S. Dimitrov, X. Shi, F. Blanc, M. A. Zwijnenburg, J. Nelson, J. R. Durrant, A. I. Cooper, Nat. Commun. 2018, 9, 4968.

Authors : Lesia Piliai a, Mykhailo Vorokhta a, TomᨠSkála a,b, Peter Matvija a, Ivan Khalakhan, a Yuliia Kosto a, Iva Matolínová a
Affiliations : a) Department of Surface and Plasma Science, Charles University, Prague, Czech Republic; b) Elettra-Sincrotrone Trieste S.C.p.A., Basovizza (Trieste), Italy

Resume : Cerium-based catalysts play an important role in C1 chemistry, preferentially for various oxidation reactions such as water-gas shift, CO-oxidation reaction, or oxidation of volatile organic compounds. A great deal of scientific activity devoted to adjusting the catalyst structure implies the enhancement of catalyst performance by the introduction of other active components to the catalyst. The complex electronic structure of cerium oxide, particularly in the reduced form, emphasizes the need for practical research, especially on the atomic level where the model studies are widely applied. In this work, we carried out a mechanistic investigation of the metal-support interaction between cerium oxide and dopants(iron and platinum) in the different model Fe/CeO2, Ce1-xFexO2, and Pt/Ce1-xFexO2 catalysts. Utilizing the synchrotron radiation photoelectron spectroscopy we determined the oxidation state of the ceria and dopants (iron and platinum) taking into account compositional and morphological features as well as the temperature treatment. It was revealed that Fe atoms instantly reacted with CeO2 and created a iron-ceria solid solution upon annealing in UHV conditions, with prevalent Fe3+ species in the structure. Also, we found that Pt oxidation state is significantly influenced by the morphology of the substrate where the presence of iron on the ceria surface prevents it from stabilizing in 4-fold oxygen pockets in the ceria lattice. However, stable Pt2+ species were found to be formed on a co-deposited iron-ceria mixed layer. Keywords: ceria, photoelectron spectroscopy, thin films, mixed oxide, iron, platinum

Authors : Rajendra B. Mujmule, Hern Kim
Affiliations : Department of Energy Science and Technology / Environmental Waste Recycle Institute, Myongji University, Republic of Korea

Resume : Carbon dioxide (CO2) utilization has attracted great attention from researchers due to environmental problems such as climate change and ocean acidification. The aerobic burning of carbon-containing materials produces CO2. It is the most major greenhouse gas that is massively produced by the combustion of fossil fuels. Thus, CO2 utilization is being considered as the best option to mitigate the greenhouse gas effect. In this regard, CO2 can be utilized as a raw material to produce value-added chemicals such as formic acid, amides, carbonates, methanol, urea, and carboxylates. Among these, the most effective and promising synthetic route is the chemical fixation of CO2 with epoxides into cyclic carbonates at the point of green chemistry and atom economy. It is also a more environmentally friendly and safer alternative to the traditional method of using diols and toxic phosgene. Cyclic carbonates have a wide range of applications, including as electrolytes in batteries, aprotic solvents in the synthesis of organic compounds, and as intermediates in the polymer and pharmaceutical industries. However, CO2 conversion remains difficult due to its thermodynamically stable and kinetically inert nature. The development of a suitable catalyst system could help to mitigate this problem. A catalyst is a crucial tool for successfully completing the transformation required for chemical synthesis. In this study, we successfully developed metal oxide, ionic liquid, and carbonaceous materials as catalysts for the cycloaddition reaction of CO2 and epoxides into cyclic carbonates. Notably, all established catalysts have been synthesized using commercially available chemicals. Catalytic systems were thoroughly examined for the presence of functional groups. All the proposed catalysts exhibited excellent catalytic performance. Using challenging internal and terminal epoxides, the catalytic applicability of established catalytic systems was investigated. Further, a possible mechanism for the chemical fixation of CO2 into cyclic carbonate was proposed based on the active sites in the established catalytic system. Keywords: Catalysts, Epoxides, CO2 utilization, Cyclic carbonates, Metal oxide, Ionic liquid, Carbonaceous materials

Authors : Lisa Heymann, Moritz L. Weber, Marcus Wohlgemuth, Marcel Risch, Regina Dittmann, Christoph Baeumer, Felix Gunkel
Affiliations : Lisa Heymann: Peter Grünberg Institut 7, Forschungszentrum Jülich GmbH, Jülich, Germany and JARA-FIT, RWTH Aachen University, Aachen, Germany; Moritz L. Weber: Peter Grünberg Institut 7, Forschungszentrum Jülich GmbH, Jülich, Germany and JARA-FIT, RWTH Aachen University, Aachen, Germany; Marcus Wohlgemuth: Peter Grünberg Institut 7, Forschungszentrum Jülich GmbH, Jülich, Germany and JARA-FIT, RWTH Aachen University, Aachen, Germany; Marcel Risch: Nachwuchsgruppe Gestaltung des Sauerstoffentwicklungsmechanismus, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany; Regina Dittmann: Peter Grünberg Institut 7, Forschungszentrum Jülich GmbH, Jülich, Germany and JARA-FIT, RWTH Aachen University, Aachen, Germany; Christoph Baeumer: (a) Peter Grünberg Institut 7, Forschungszentrum Jülich GmbH, Jülich, Germany and JARA-FIT, RWTH Aachen University, Aachen, Germany and (b) MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, Enschede, Netherlands; Felix Gunkel: Peter Grünberg Institut 7, Forschungszentrum Jülich GmbH, Jülich, Germany and JARA-FIT, RWTH Aachen University, Aachen, Germany

Resume : To compensate demand-and-supply electricity peak times, efficient hydrogen energy storage systems are one of the most urgently needed technologies in the near future. Today, commercially available water electrolyzers run with Ir or Ru based catalyst materials in acidic media. There is a big need to shift this catalyst composition to more economically available and earth abundant elements. Transition metals such as Fe, Co and Ni are more sustainable catalysts that are used in alkaline water splitting but they do not reach the efficiency of Ir/Ru based catalysts. As alternative to the Ni/Fe/Co alloys in alkaline water electrolysis, the perovskite oxides (A1-xA’xBO3) of those 3d transition metals achieve high efficiency for the sluggish oxygen evolution reaction (OER) , i.e. the kinetically limiting half-cell reaction for hydrogen production. Different perovskite oxide compositions exhibit a broad range of OER performance trends determined by the so called OER descriptors. They can show insulating to highly conducting behavior and ionic to covalent B-O binding. In this work, we developed model epitaxy perovskite oxide electrocatalysts to investigate the two prominent OER activity descriptors B-O covalency and accessible hole carriers at the catalyst-electrolyte interface to improve the understanding for a rational OER catalyst design. The Co-O covalency in perovskite oxide cobaltites like La1-xSrxCoO3 is believed to impact the electrocatalytic activity in the OER. Additionally, space charge layers through band bending at the interface to the electrolyte may affect the electron transfer into the electrode, complicating the analysis and identification of true OER activity descriptors. Here we use atomically defined bilayer stacks of cobalt based perovskite oxides to achieve a fine-tuning of the surface B-O covalency and carrier concentration, which enables us to correlate the two OER descriptors to the observed OER activity. In this way, we separate the influence of covalency and band bending in hybrid epitaxial bilayer structures of highly OER active La0.6Sr0.4CoO3 and less active LaCoO3. Ultra-thin LaCoO3 capping layers of 2-8 unit cells on La0.6Sr0.4CoO3 show intermediate OER activity between La0.6Sr0.4CoO3 and LaCoO3 that is evidently caused by the increased surface Co-O covalency compared to single LaCoO3 as detected by x-ray photoelectron spectroscopy. A Mott Schottky analysis revealed low flat band potentials for the different LaCoO3 thicknesses, indicating that no limiting extended space charge layer exists under OER conditions as all catalyst bilayer films exhibited hole accumulation at the surface. The combined x-ray photoelectron spectroscopy and Mott Schottky analysis thus enables to differentiate between the influence of the covalency and intrinsic space charge layers, which are indistinguishable in a single physical or electrochemical characterization. Our results emphasize the prominent role of transition metal oxygen covalency in perovskite electrocatalysts and introduces a bilayer approach to fine-tune the surface electronic structure [1]. [1] L. Heymann, M. L. Weber, M. Wohlgemuth, M. Risch, R. Dittmann, C. Baeumer, F. Gunkel ACS Appl. Mater. Interfaces 2022, 14, 14129-14136.

10:30 COFFEE BREAK    
Mechanical and Thermal Energy (II) : Felix Gunkel
Authors : Jin-Chong Tan (1), Yueting Sun (1,2), Sven M.J. Rogge (3), Clive R. Siviour (4), Veronique Van Speybroeck (3)
Affiliations : (1) Multifunctional Materials & Composites (MMC) Laboratory, Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, United Kingdom. (2) School of Engineering, University of Birmingham, Edgbaston, Birmingham, United Kingdom. (3) Center for Molecular Modeling (CMM), Ghent University, Zwijnaarde, Belgium. (4) Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, United Kingdom.

Resume : Zeolitic imidazolate frameworks (ZIFs) are a promising class of nanoporous metal-organic frameworks (MOFs) due to their thermomechanical and chemical stability. There is an increasing number of studies devoted to the mechanical properties of ZIFs, yet more work should be done to address their structural dynamics [1] and mechanical energy conversion, and their rate-dependent mechanical response. All of which are central to the engineering of real-world applications, such as energy absorption and dissipation, structural damping, and novel impact mitigation systems [2]. We demonstrate a liquid intrusion-extrusion approach for energy absorption by leveraging nanoporous frameworks. This is enabled by nanofluidic confinement mechanisms, occurring at the molecular length scale, when the hydrophobic nanopores of ZIFs are subject to a hydrostatic pressure [3]. We found that the specific energy absorption capacity is of the order of 1-10 J/g under a quasi-static deformation [4], which is comparable to the damping performance of the foams, rubbery polymers, and hollow truss structures. Remarkably, we discovered that the damping capacity of ZIFs is strongly strain-rate dependent, whereby an energy absorption capacity of 100’s J/g was accomplished under high-rate deformation exceeding 1000 s^-1 [5]. Our ab initio molecular dynamics simulations reveal that this rate-dependent effect originates from the intrinsic nanosecond timescale required to form critical-sized confined water clusters being transported across the hydrophobic ZIF cages [5]. Furthermore, multicycle liquid intrusion-extrusion experiments confirmed that the nanoporous framework is viscoelastic, such that mechanical recovery is achieved through structural relaxation over time. The results could open up the new field of rate-dependent nanoporous material dynamics, and instigate development of next-generation hydrophobic materials geared towards vibrations, damping, and impact protection technologies. [1] Ryder MR, Civalleri B, Bennett TD, Henke S, Rudić S, Cinque G, Fernandez-Alonso F, Tan JC. Identifying the Role of Terahertz Vibrations in Metal-Organic Frameworks: From Gate-Opening Phenomenon to Shear-Driven Structural Destabilization, Phys. Rev. Lett. 113 (2014) 215502. [2] Tan JC, Marmier A, Rogge SMJ, Moggach S, Sun Y. Mechanical Behaviour of Metal-Organic Framework Materials. London: Royal Society of Chemistry, 2022 (In Press). [3] Sun Y, Li Y, Tan JC. Framework flexibility of ZIF-8 under liquid intrusion: discovering time-dependent mechanical response and structural relaxation, Phys. Chem. Chem. Phys. 20 (2018) 10108. [4] Sun Y, Li Y, Tan JC. Liquid Intrusion into Zeolitic Imidazolate Framework-7 Nanocrystals: Exposing the Roles of Phase Transition and Gate Opening to Enable Energy Absorption Applications, ACS Appl. Mater. Interfaces 10 (2018) 41831. [5] Sun Y, Rogge SMJ, Lamaire A, Vandenbrande S, Wieme J, Siviour CR, Van Speybroeck V, Tan JC. High-rate nanofluidic energy absorption in porous zeolitic frameworks, Nat. Mater. 20 (2021) 1015.

Authors : Rahul Kumar Singh, Antoni Gil Pujol, Purvi Jain, Alessandro Romagnoli
Affiliations : Rahul Kumar Singh ; Antoni Gil Pujol ; Purvi Jain - Surbana Jurong – Nanyang Technological University Corporate Lab, 61 Nanyang Drive, 637355, Singapore Alessandro Romagnoli - School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore

Resume : The rise in global warming is increasing the necessity of more energy efficient solutions in terms of technologies and materials. During the last years, this necessity has been foreseen in refrigeration field, where the demand for building cooling (commercial and residential), and refrigeration and cold storage facilities for industrial applications is becoming more and more relevant for a globalized economy. All these systems are extremely energy intensive and add on to the peak electricity demands of the facility. Cold thermal energy storage (CTES) systems based on phase change materials (PCM) present an important solution to reducing the global carbon emissions by shifting the peak energy requirements of these facilities. PCMs have been critical for such systems and have found use in applications such as cold food storage, free cooling of buildings, storing regasification waste energy and more recently even in transport of Covid vaccines at ultra-low temperatures(<-300C). However, the PCMs at these temperatures suffer with two main energy inefficiencies that of low thermal conductivity and supercooling. Supercooling is defined as the difference between the crystallization (TC) and melting (Tm) points of a PCM when measured with a non-zero cooling rate which is the case in most of the real systems. The accurate determination of supercooling values is critical for correct simulation of the CTES system and optimization of the charge and discharge cycles for the PCM. Apart from the material composition and encapsulation, the supercooling also depends on the scale of measurement with the differential scanning calorimetry (DSC) apparatus, which uses samples of milligrams, and bulk systems using kilograms of PCM. Most of the previous studies on supercooling have been performed at laboratory scale using DSC. From the literature reviewed and to the best of knowledge of the authors, the study on system level supercooling characterization at ultra-low temperature range is rare. To focus on the above, a commercial eutectic PCM material with a melting peak of -50 °C has been chosen and a helicoidal heat exchanger is used to test out system level supercooling in a tank carrying 4 kg of material. The prototype system showed a supercooling value ranging between 5-10 °C below the melting point. For small scale measurements, with weight of PCM tested in mg, DSC tests show a material sub-cooling range greater than 30 °C. Due to this large difference in the sub-cooling numbers at small scale and prototype scale, a set-up based on T-history measurement with ~50 grams of PCM are developed. The supercooling values measured with this set-up is between 10-15 °C which is much closer to the system measurement. The current results suggest that DSC crystallization data should not alone be taken as a standard to measure system behaviour especially at ultra-low temperatures. This study is a part of ongoing research on the accurate measurement of material properties at ultra-low temperatures to be used in CTES system designing.

Authors : Josh D. Littlefair*, Marco Tortora†, Paweł Zajdel‡, Alexander R. Lowe§, Mirosław Chorążewski §, Juscelino B. Leão**, Grethe V. Jensen**, Markus Bleuel**, Alberto Giacomello†, Carlo M. Casciola†, Simone Meloni*, Yaroslav Grosu††
Affiliations : *Università di Ferrara, Italy †Sapienza Università di Roma, Italy ‡University of Silesia in Chorzów, Poland §University of Silesia in Katowice, Poland **NIST Center for Neutron Research, United States ††CIC energiGUNE, Spain

Resume : Materials possessing negative linear compressibility (NLC), whose size increases in at least one of their dimensions upon compression, are very rare, while those demonstrating negative volumetric compressibility (NVC) are exceptional. We have recently shown a general strategy to obtain NLC and NVC based on the liquid intrusion in flexible and hydrophobic porous materials (Nano Lett. 2021, 21, 2848). Indeed, one can achieve the proper mixing of flexibility and hydrophobicity required for NLC and NVC by exploiting the tunability of metal-organic frameworks (MOFs). On top of the importance of this discovery from the point of view of fundamental research, NLC and NVC via liquid intrusion in MOFs and, possibly, other nanoporous material allows the development of technological applications such as nanovalves, opening novel perspectives for nanofluidics and other fields. In this contribution we will describe our recent experimental and theoretical results explaining the mechanism beneath NVC in MOFs, namely in ZIF-8. By combining liquid porosimetry, in situ neutron diffractometry and advanced sampling simulations we revealed that the key to achieve NVC is the presence of peculiar, star-like windows among ZIF-8 cavities, which have a size comparable with that of the molecules of the intruding liquid, water in our case. Ab initio simulations have proved that lattice expansion during intrusion is due to the rotation of ZnIm4 (Im = methyl imidazolate) units, suggesting a specific characteristic of the MOF that could be tuned to maximize NVC.

Authors : Alexander R Lowe, Miroslaw Chorazewski
Affiliations : Institute of Chemistry, University of Silesia in Katowice, 40-006 Katowice, Poland

Resume : Scanning Transitiometery, is an analytical technique which can be used to record the mechanical and thermal effects of a physico-chemical process over a wide range of different pressures and temperatures. This is done by controlling the rate of change over three state variables of Temperautre, Pressure, and Volume. From these experiments it is possible to evaluate the amount of mechanical and thermal energy stored. It is with this technology it becomes possible to accurately determine which combinations of materials are possible to be exploited for energy storage, both mechanical and thermal. The aim of the poster is to present the technique and the recent contributions it has made to current and future projects in energy storage in high-pressure and high-temperature conditions with simple and complex systems.

Authors : Sebastiano Merchiori, Mirosław Chorążewski, Paweł Zajdel, Alexander Lowe, Simone Meloni, Yaroslav Grosu
Affiliations : Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy; Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice, Poland; Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500, Chorzow, Poland; Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice, Poland; Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy; CIC EnergiGUNE, Basque Research and Technology Alliance (BRTA), Alava Technology Park, Albert Einstein 48, 01510 Vitoria-Gasteiz, Spain

Resume : The development of efficient and compact energy conversion methods is a crucial challenge driven by the rising of global energy consumption. Reversible intrusion of non-wetting liquid into nanopores is a new method of energy storage in the form of solid-liquid interfacial energy. Lyophobic flexible nanoporous materials, acting as Molecular Springs (MSs), can be used for thermal-to-mechanical energy conversion when coupled with water.[1] A peculiar property of MSs is that upon charging (intrusion) they store not only mechanical energy, but also thermal energy–forced intrusion is accompanied by endothermic effect of solid-liquid interface development. Such thermal energy is also restored during the exothermic extrusion. In particular for the high stable Cu2L(L=3,3’,5,5’-tetraethyl-4,4’-bipyrazolate) MOF[2-4] a thermal-to-mechanical conversion efficiency of∼30% was recently measured.[1] This system demonstrates highly pronounced temperature dependent compressibility, which results in a non-linear temperature dependence of intrusion-extrusion pressure: at higher temperature effective pore size before intrusion is smaller compared to the one at lower temperature. Lower pore size leads to higher intrusion pressure according to Laplace capillary pressure.[5] The same effect means that the effective porosity (pore volume available for water molecules to occupy) will be smaller at higher temperature. Therefore, intrusion/extrusion pressure increases with temperature while intrusion/extrusion volume decreases at higher temperature. In addition, Molecular Dynamics simulations shows that under isobaric conditions water vapor develops inside MOF channels and as temperature increases, the density of vapor molecules increases. This phenomenon, together with the flexibility of the MOF, may represent an additional thermodynamic factor influencing the intrusion mechanism. References [1] Chorążewski M., Zajdel P., Feng T., Luo D., Lowe A., Brown M. C., Leão J. B., Li M., Bleuel M. Jensen G., Li D., Faik A., Grosu Y., ACS Nano 2021, 15, 9048-9056;[2] Wang J-H., Li M., Li D., Chem. Eur. J. 2014, 20, 12004 – 12008;[3] Grosu Y., Li M., Peng Y-L., Luo D., Li D., Faik A., Nedelec J-M., Grolier J-P., Chem. Phys. Chem 2016, 17, 3359 –3364;[4] Zajdel P., Chorążewski M., Leão J. B., Jensen G. V., Bleuel M., Zhang H-F., Feng T., Luo D., Li M., Lowe A., Geppert-Rybczyńska M., Li D., Grosu Y., J. Phys. Chem. Lett. 2021, 12, 4951-4957;[5] Lowe A., Wong W. S. Y., Tsyrin N., Chorążewski M., Zaki A., Geppert-Rybczyńska M., Stoudenets V., Tricoli A., Faik A., Grosu Y., Langmuir 2021, 37, 4827-4835.

12:30 LUNCH BREAK    
Solar Energy Storage (I) : Víctor Antonio de la Peña
Authors : Débora Ruiz-Martínez, Rebeca Marcilla
Affiliations : Electrochemical Processes Unit, IMDEA Energy, Avenida Ramón de la Sagra 3, 28935 Móstoles, Madrid, Spain

Resume : The use of energy from renewable energy sources is becoming urgent over the last several years to decrease fossil fuel demand and large CO2 emissions. The sun is the most exploitable and limitless energy source. However, the intermittent nature of sunlight necessitates the development of efficient energy storage devices to store the photogenerated electricity. In this context, solar flow batteries (SFBs) have been proposed as an attractive renewable technology for sunlight harvesting and chemically storage of energy. In such technology, the redox couples in liquids electrolytes store the photogenerated electrons or holes as chemical energy. Recently, some works have been published describing the performance of monolithically integrated SFBs. They show some advantages with respect to non-integrated ones such as a safety performance of the photoelectrode, and the more cost-effective production due to their compact design[1]. Nevertheless, SFBs suffer from poor round trip efficiency due to the limits of the solar conversion components and the voltage mismatch between the photoelectrode and the redox potential of the electrolytes. Moreover, similar to conventional redox flow batteries they still make use of expensive and ineffective ion-selective membranes such as Nafion to separate the redox electrolytes. Here we review the state-of-art of this technology highlighting the multiple current challenges and presenting some interesting approaches that will be explored in the framework of LIGHT-CAP European Project. One of the main objectives is not only to design more efficient SFBs making use of nanostructured materials with multiple electron/hole properties, but also to develop a membrane-free SFB in which the multi-charge transfer process might take place at the liquid-liquid interface. To do so, we will first explore the matching of developed photo electrodes with the different battery chemistries developed within the framework of MFreeB ERC Consolidator Grant [2]. References [1] Wenjie Li, Song Jin. Design principles and developments of Integrated Solar Flow Batteries. Acc. Chem: Res. 2020, 53, 2611-2621. [2] Navalpotro, P. et at. Critical aspects of membrane-free aqueous battery based on two immiscible neutral electrolytes. Energy Storage Mater. 2020, 26, 400-407. Acknowledgments The project LIGHT-CAP has received funding from the European Union’s Horizon 2020 Research and Innovation program under grant agreement no.[101017821]. This work has been partially funded by project MFreeB which have received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant Agreement No. 726217).

Authors : Nastaran Kazemi Tofighi,1 Aswin Asaithambi,1 Ivet Maqueira Albo, 1.2, Nicola Curreli, 1 Andrea Camellini,1. Ilka Kriegel, 1
Affiliations : 1. Functional Nanosystems, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy; 2. Physics Department, University of Genoa, Via Dodecaneso 33, 16146 Genoa, Italy

Resume : Research into new materials and its technological advances might improve the efficiency in the use of renewable energy sources, fostering new opportunities, with solar radiation among the most promising alternatives for meeting the global energy demand. In light of this, the objective is focused on the research and study of materials that are able to support the mechanisms behind the solar energy applications. Nanoscale materials display very promising characteristics as light energy absorbers and transmitters. In particular, the size and thickness dependence allows modifying their single and combined optoelectronic response, which can be exploited for energy applications. Optical spectroscopy and microscopy represent important tools to extract fundamental light-matter interactions, which represent the initial processes towards solar energy conversion. In this contribution, it will be discussed the characterization of zero-dimensional nanocrystals and two-dimensional materials, such as perovskites or transition metal dichalcogenides, in an effort to explore their joint potential for applications in nanotechnology.

Authors : Anjana Panangattil Muraleedharan, Michele Ghini, Luca Rebecchi, Andrea Rubino, Andrea Camellini, Ilka Kriegel
Affiliations : Functional Nanosystems, Istituto Italiano di Tecnologia, Genova, Italy

Resume : Energy from sunlight is a potential alternative solution for the global sustainable energy crisis. Solar power can be exploited effectively by combining light energy conversion and storage functions into one single component by taking advantage of a novel approach which helps to avoid the losses associated with the compartmentalization of these two functions [1]. Photodoping of metal oxide nanocrystals can be considered as one of the most interesting strategies for the realization of this task. This photo-induced n-type doping allows multiple charge accumulation of electrons induced by absorption of high-energy photons above the band gap of the material[1, 2]. In fact, it has been reported that the capacitance values exhibited by doped metal oxide nanocrystals after photodoping may rival those of the best supercapacitors used in commercial energy-storage devices, exposing these systems as extremely promising materials for future light-driven energy storage solutions [3]. To understand and optimize the charge accumulation process of metal oxide nanocrystals during the light driven charging, a spectro-electrochemical approach capable of relating the optical response to the electrochemical signatures is necessary [4]. We have charged the metal oxide NCs with a light source in a controlled atmosphere, simultaneously monitoring the changes in the open circuit voltage by extending the instrumental set up for photodoping with a Potentiostat. A long-term impact on the development of solar chargeable devices can be envisaged by the fruitful implementation of photodoping in solar energy storage applications. 1. [1] M Ghini et al Nanoscale, 2021, 13, 8773– 8783 2. [2] I. Kriegel et al J. Phys. Chem. C 2020, 124, 8000−8007 3. [3] Brozek et al Nano Lett. 2018, 18, 3297−3302 4. [4] Agarwal et al ACS Photonics 2018, 5, 2044−2050

Authors : Mariam Barawi,1 Miguel Gomez‐Mendoza,1 Freddy E. Oropeza,1 Giulio Gorni,2 Ignacio J Villar-Garcia,3 Sixto Giménez,4 Victor A. de la Peña O'Shea1 and Miguel García-Tecedor*1
Affiliations : 1. Photoactivated Processes Unit, IMDEA Energy, Avda. Ramón de la Sagra, 3, Móstoles, 28935, Spain. 2. CLÆSS Beamline, ALBA Synchrotron, Carrer de la Llum 2-26, Cerdanyola del Valles, 08290, Spain. 3. NAPP Endstation, CIRCE Beamline, ALBA Synchrotron, Carrer de la Llum 2-26, Cerdanyola del Valles, 08290, Spain. 4. Institute of Advanced Materials (INAM), Universitat Jaume I, Avda. Vicente Sos Baynat, s/n, Castelló, 12006, Spain.

Resume : BiVO4 is one of the most attractive candidates for photoelectrochemical (PEC) water splitting due to its suitable optoelectronic properties as its bandgap (2.4 eV) and its energy band edge positions. However, it also suffers from poor carrier transport and surface recombination. In order to overcome these limitations, a great effort has been made to enhance the performance of BiVO4 photoanodes through different approaches such as nanostructuring, heterostructuring with other metal oxides, the deposition of co-catalysts and the employment of post-synthetic treatments. Among the different reported post-synthetic treatments, several studies were focused on different light exposures enhancing the performance of BiVO4. On this direction, several works reported oxygen-vacancies-rich BiVO4 photoanodes based on different post-synthetic methods. The present study proposes a laser irradiation method to superficially reduce BiVO4 photoelectrodes that boosts their water oxidation reaction performance. The origin of this enhanced performance towards Oxygen Evolution Reaction (OER) was studied by a combination of a suite of structural, chemical, and mechanistic advanced characterization techniques including XPS, XAS, EIS and TAS, among others. We found that the reduction of the material is localized at the surface of the sample and that this effect creates an effective n-type doping and a shift to more favorable energy band positions towards water oxidation. This thermodynamic effect, together with the change in sample morphology to larger and denser domains, result in an extended lifetime of the photogenerated carriers and an improved charge extraction. In addition, the stability in water of the reduced sample was also confirmed. All these effects, result on a two-fold increase in the photocurrent density of the laser treated samples.

15:15 COFFEE BREAK    
Advanced Characterization (I) : Liese Hubrechtsen
Authors : Santosh Kumar,(1) James Counter,(1) Paul B. Webb,(2) Stephen Francis,(2) Federico Grillo,(2) Pilar Ferrer,(1) David C. Grinter,(1) Anna B. Kroner,(1) Georg Held,(1)
Affiliations : (1) Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK, (2) School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK,

Resume : Any bottom-up design of energy storage or conversion systems has to be based on a molecular-level understanding of the components involved (photo-active materials, catalysts, or membranes) and the chemical changes they undergo in reactive environments. In order to facilitate spectroscopic investigations of such materials, we have developed a suite of operando cells for synchrotron-based soft X-ray photoelectron and absorption spectroscopy. All cells feature a simple, user-friendly design with replaceable windows, which can be either of X-ray transparent silicon nitride or of water permeable membrane material (e.g. Nafion). The latter material is particularly suitable for liquid flow or electrochemical cells and enables measuring photoelectrons emitted from the membranes or from catalyst material deposited at the solid-liquid interface outside the cell. Both types of cells have been tested and results from model (photo) catalysts will be presented. Silicon nitride windows are transparent for X-rays and are used for X-ray absorption spectroscopy of materials inside the cells. They can be used with liquid cells but also with gas-phase micro-reactors at high pressures, up to 2 bar, and temperatures up to 400° C. Materials can be studied simultaneously using total electron yield (TEY) and fluorescence-yield (FY) detection mode, which provide a useful contrast when investigating surface phenomena, such as metal-support interactions and molecular adsorption. The microreactor was successfully tested studying gas encapsulation within metal-organic framework materials and the structural evolution of a series of Fischer-Tropsch catalysts. This presentation will highlight the design and broad scope of the above operando cells and micro-reactors and discuss future plans.

Authors : Lilian Moumaneix, Akseli Rautakorpi, Tanja Kallio
Affiliations : Department of Chemistry and Materials Science, Aalto University, 00076 Aalto, Finland

Resume : In view of the alarming reports on the risks caused by a global elevation of temperatures, disruptive energy technologies are urgently needed. Cold fusion has recently regained interest from several research projects due to its potential as a breakthrough zero-emissions heat generation technology. When inserting deuterium atoms into the palladium lattice, there is a chance to observe the production of excess heat which can be sustained for up to several weeks. Over the years, a significant amount of studies have attempted to reproduce the initial results from Fleischmann et al., bringing a better understanding of the critical conditions to achieve in order to observe excess heat production. Parameters such as the applied current density (> 100, the cathode temperature (> 60 °C), or the deuterium loading (D/Pd > 0.85) have been found to greatly influence the result of experiments. The latter has attracted the attention of many fields of research, e.g. hydrogen storage, purification, sensors or catalysis, as many properties of the PdH(D)x system vary with x. As part of the European HERMES project, our research group has focused on studying the electrochemical absorption of both hydrogen and deuterium atoms into Pd nanoparticles (NPs). In theory, an overpotential of 120 mV produces the thermodynamic equivalent of approximately 100 atm of pressure. In this work, measurements were carried out in a rotating disk electrode setup (RDE) as well as in a proton pump configuration, the latter allowing low voltages up to -1 V, high current densities (> 500, and operation at temperatures up to 80 °C. A novel modelling procedure has been developed to extract pertinent information from the electrochemical desorption of H(D), such as the proportion of H(D) atoms inserted into the Pd lattice or onto the particles surface. In addition to this, comparisons with wide-angle X-ray scattering measurements have been performed on the H(D) adsorption/desorption. The influence of loading voltage, loading duration, temperature, and isotope variation has been investigated, leading to mechanistic and kinetic information on the PdH(D) system. The loading voltage was identified as having the largest impact on the H(D) absorption, with H/Pd values as high as 0.20 ± 0.02 in the proton pump and up to 0.47 ± 0.02 in the RDE setup. Interestingly, saturation of the Pd NPs was achieved in 3 – 5 s, compared to several minutes for Pd wires or thin films, as reported in the literature. Furthermore, the existence of an optimal temperature for the insertion of H into Pd was determined, likely due to an optimal balance between the H adsorption rate and the actual diffusion rate of H into the Pd lattice. Using novel materials along with experimental setups rarely studied could bring new insights for cold fusion investigations. Other applications involving PdHx, such as CO2 reduction to HCOOH, could also benefit from these new results and modelling procedure.

Authors : Ivet Maqueira Albo, Nastaran Kazemi Tofighi, Andrea Camellini, Aswin Asaithambi, and Ilka Kriegel
Affiliations : Functional Nanosystems, Istituto Italiano di Tecnologia, Via Morego 30,16163 Genova, Italy

Resume : Monitoring the surface-related chemical properties of inorganic nanomaterials to understand their morphology-dependent behavior in complex photochemical reactions under operating conditions is a key aspect to advance their applications. In-situ steady-state and time-resolved photoluminescence and Raman micro-spectroscopy are effective tools to accomplish these observations. When performed within an electrochemical cell that allows controlling precisely their environment, these techniques could provide a great insight into material modifications during light-triggered chemical reactions as well as into the formation of intermediate chemical species during oxidation and reduction reactions. Here, we propose a high-end custom-made micro-spectroelectrochemical setup that allows us to perform the aforementioned investigations by monitoring simultaneously the electrochemical signatures, as well as the optical features. As case studies, we focus on nanomaterials, such as doped metal oxide nanocrystals (e.g. Sn doped In2O3), lead halide perovskite nanocrystals (e.g. CsPbBr3), two-dimensional transition metal dichalcogenides (e.g. MoS2, MoSe2) as well as their hybrids. We foresee that by using the presented setup and technique on hybrid systems, we additionally extract carrier behaviors and increase our understanding of charge/energy transfer between two components of the desired heterostructure.

Authors : Juan de Dios Sirvent(a), Giulio Cordaro(b), Dominique Thiaudière(c), Marc Núñez(a), Alex Morata(a), Guilhem Dezanneau(b), Federico Baiutti(a,d), Albert Tarancón(a,e)
Affiliations : (a) Department of Advanced Materials for Energy, Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, Sant Adrià del Besòs, Barcelona 08930, Spain (b) Université Paris-Saclay, CentraleSupélec, CNRS, Lab. SPMS, 91190 Gif-sur-Yvette, France (c) Synchrotron Soleil, 91192 Gif-Sur-Yvette, France (d) Department of Materials Chemistry, National Institute of Chemistry, Hajdrihova 19, Ljubljana SI-1000, Slovenia (e) ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain

Resume : As research on materials science and in particular on solid oxide cells progresses, the need for more advanced, systematic and effective methodologies for discovering novel materials and their application areas becomes evident. The development of high-throughput tools for screening complete formulation families has risen as a compelling approach for satisfying this need. These tools make it possible to synthesize and characterize a whole set of samples in a single run, ensuring the same experimental conditions in every measurement and enabling more efficient materials screening. Here, we report on a systematic study of the La0.8Sr0.2CoxMnyFe1-x-yO3 (LSCMF) perovskite ternary system of air electrodes. Combinatorial pulsed laser deposition was employed on the parent materials (i.e. LSC, LSM and LSF), resulting in the growth of a thin film wafer with graded composition. The three single-phase target materials were alternatively deposited on opposite edges of the substrate at high temperature. The formation of an intermixed layer that contains the compositions of the whole ternary diagram was obtained in a single deposition run. The multicomponent sample was characterized by X-ray diffraction, X-ray fluorescence spectroscopy, Raman spectroscopy and spectroscopic ellipsometry, allowing mapping of the structural, crystallographic and electronic properties (e.g. lattice parameter, Raman shift peak and optical absorption coefficient). Most interestingly, the electrochemical performance of the whole system was measured at once by impedance spectroscopy using an automated large-area high temperature testing station. This setup allowed the simultaneous recording of the area specific resistance of the thin film at a given temperature and for each composition. The results obtained pave the way to a deeper understanding of the LSMCF cathode family based on the correlation of structural and electrochemical properties for a wide materials space, as well as setting up a general methodology for high-throughput research of electrochemical materials.

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Solar Energy Conversion (II) : Albert Tarancón
Authors : Mariam Barawi*1, Elena Alfonso1, Carmen G. López-Calixto1, Alberto García1, Alba García1, Ignacio J. Villar-García2, Marta Liras1, Victor A. de la Peña O´Shea 1
Affiliations : 1- Photoactivated Proceses Unit IMDEA Energy Institute, Av. Ramón de la Sagra 3, 28935 Móstoles, Madrid, Spain 2- CIRCE Beamline. ALBA Synchrotron, Barcelona, Spain.

Resume : Solar energy conversion into fuels such as hydrogen through photoelectrochemical (PEC) cells is an attractive way to solve the problems present in the actual energetic system. (1) Despite the any advances that have been in this line, is still necessary to develop new materials and cell configurations to take this technology to a higher scientific level. The application of organic polymers for is a hot topic that continues to grow due to the promising optoelectronic properties of this class of semiconductors. Conjugated polymers exhibit advanced properties because of it particular conjugation that confers it a huge conductivity through the whole structure. (2) In particular, Conjugate Porous Polymers (CPP) offers a higher photostability and robustness that is fundamental for long term application, but their synthesis often leads to a large-particle powder, unsuitable for preparing thin films, key to preparing high-quality photoelectrodes.(3) In this work, we present an innovative mini emulsion synthesis of a CPP, Nano IEP-1 (Imdea Energy Polymer-1) that leads to a 500 nm particles, adequate for thin film preparation. The electronic structure and was determined by a combination XPS, electrochemistry and UV-VIS spectroscopy. The photoelectrochemical response of Nano IEP-1 reveals a p type semiconductor with photocurrents at different applied potentials that suggest its potentiality for solar energy conversion. In this way, a tandem PEC cell was assembled to enhance its properties and achieve higher photocurrents. Two hybrid photoelectrodes were assembles by the heterojunction of Nano-IEP-1 and inorganic nanocrystals (TiO2 and CuI). The energy diagram calculated before shows an ideal position of the energy bands in order to use the synthesized polymer both as photocathode and as an electron injector to TiO2 in photocatalytic reactions (to former the photoanode) and CuI will works as hole collector in the photocathode. The formed hybrid photoelectrodes have been characterized by X-ray diffraction, SEM, EDX and AFM. A series of photoelectrochemical measurements have been performed in a three electrode cell configuration, using the hybrid materials as working electrodes. The photoelectrodes presents improved photovoltages and photocurrents on the hybrids electrodes compared with TiO2 and the CPP alone, suggesting and adequate light absorption and charge transfer between them. Besides, Electrochemical Impedance Spectroscopy (EIS) was performed to confirm the improved charge transfer observed when illuminating the hybrid photoelectrodes. We build them a tandem PEC cell in a monolithic configuration and perform a series of photoelectrochemical measures in two electrode configuration, achieving a photovoltage of 0.9 V and photocurrents of around 0.5 mA/cm2 in a two-electrode configuration. Finally, the cell was biased at 0.6 V and hydrogen evolution was observed and quantified by gas chromatography achieving 581 µmol of H2 in a one-hour reaction.

Authors : Liudmila Starodubtceva (a,b), Piotr J. Cegielski (a), Sebastian Lukas (b), Martin Otto (a), Shayan Parhizkar (a), Max C. Lemme (a,b). a) AMO GmbH, Advanced Microelectronic Center Aachen, Otto-Blumenthal-Str. 25, 52074 Aachen, Germany b) Chair of Electronic Devices, RWTH Aachen University, Otto-Blumenthal-Str. 2, 52074 Aachen, Germany
Affiliations : This work has received funding from the German Ministry of Education and Research (BMBF) under grant agreement 16ES1121 (ForMikro-NobleNEMS) and from the European Union’s Horizon 2020 research and innovation programme under grant agreements 951774 (FOXES), 881603 (Graphene Flagship Core 3), 825272 (ULISSES), 952792 (2D-EPL) as well as from German Research Foundation (DFG) project LE 2440/12-1 (Hyper-Lase).

Resume : Halide perovskites are direct bandgap semiconductors that can be deposited by low-cost processes, making them a promising candidate for optoelectronic devices like solar cells [1], light emitting diodes [2], and lasers [3, 4]. However, perovskites are unstable when subjected to moisture, heat, oxygen, and long light exposure, which severely hinders their implementation in commercial devices. In the Dunham’s work [1] it was proven that highly conductive and hydrophobic graphene (Gr) prevents diffusion of water and oxygen into perovskite layers. Moreover, Gr can block ion migration, improving stability and increasing the lifetime of perovskite devices [5]. Gr cannot be grown directly on perovskites but has to be transferred from a growth substrate like copper or sapphire. The transfer is commonly performed using water followed by annealing at temperatures above 100°C [6, 7]. Both process components cause perovskite degradation. Few low-temperature processes not involving water are available to date [1, 8] and, to the best of our knowledge, a comprehensive study of the influence of the type of polymer membrane and its glass transition temperature on the transferred graphene quality is missing. Here, low-temperature dry transfer of monolayer chemical vapor deposited (CVD) graphene onto the perovskite CsPbBr3 was investigated. Before the transfer, the Gr grown on copper was coated with a polymer support layer membrane. Next, copper was etched by a mixture of hydrochloric acid, hydrogen peroxide and deionized water, which released Gr attached to the polymer layer. After rinsing with deionized water and drying, the Gr – polymer stack was transferred onto the perovskite and heat was applied to ensure that the Gr fully adheres. In this work, two types of polymers with high and low glass transition temperatures (Tg) were used as a support layer: PMMA (Poly(methyl methacrylate)) with a Tg of 105°C and PPC (polypropylene carbonate) with a Tg of 40°C. It is shown that depending on the Tg, the transfer temperature and transfer duration can be adjusted: 130°C for 60 minutes and 50°C for 5 minutes for PMMA and for PPC, respectively. Afterwards, the polymer was dissolved in a nonpolar solvent such as chlorobenzene or toluene. We found that during the Gr-PMMA transfer air bubbles are trapped under the Gr sheet. Thus, Gr is partly delaminated and CsPbBr3 is exposed to oxygen and moisture. This causes perovskite degradation evidenced by a drop in amplitude of photoluminescence intensity of the perovskite that is not covered with Gr by a factor of 50. Scanning electron microscopy shows an appearance of pinholes on CsPbBr3-Gr surface after the transfer. This is attributed to a perovskite recrystallization that is expected to occur at 130°C. In contrast, the CsPbBr3 morphology does not change after Gr transfer using the PPC membrane, which we attribute to the lower processing temperature. In conclusion, graphene dry transfer processes with different polymer supporting layers have been investigated with respect to their compatibility with CsPbBr3 perovskite. We demonstrated that the process temperature can be selected with the polymer glass transition temperature. Moreover, photoluminescence spectroscopy revealed that Gr indeed protects the perovskite from air exposure if the transfer is compatible and thus is a promising material for enhancing the stability of perovskite devices. [1] Dunham B. et al., ACS Appl. Energy Mater. 5, 52 (2022) [2] Kim, YH. et al., Nat. Nanotechnol. (2022) [3] Cegielski P. et al., Nano Lett. 18, 11 2018 [4] Pourdavoud N. et al., Adv. Mat.31, 39 2019 [5] Hongzhen S. et al., Small methods 4, 10 (2020) [6] Ullah S. et al., Nano res. 14, 3756 (2021) [7] Wagner S. et al, Microelectron. Eng. 159 (2016) [8] Ishikawa R. et al., ACS Appl. Energy Mater. 2, 171 (2019)

Authors : Luca Rebecchi, Andrea Rubino, Nicolò Petrini, Ilka Kriegel
Affiliations : Functional Nanosystems, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy - Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Genova, Via Dodecaneso 31, 16146 Genova, Italy; Functional Nanosystems, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy; Functional Nanosystems, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genova, Italy - Dipartimento di Fisica, Università degli Studi di Genova, Via Dodecaneso 33, 16146, Genova, Italy; Functional Nanosystems, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genova, Italy;

Resume : Transparent, conductive compounds constitute a fundamental class of materials. Combining high electrical conductivity and optical transparency in the visible range of the electro-magnetic spectrum. They are fundamental for opto-electronics and energy-related industries. These properties are usually achieved by doping metal oxides, creating Transparent Conductive Oxides (TCOs). Conductivity is controlled by doping, while optical transparency is given by a sufficiently large bandgap. Currently, several materials are used, with the most diffused being Indium Tin Oxide (or ITO). However, several alternatives have been developed, such as Fluoride Tin Oxide (FTO) and Aluminum Zinc Oxide (AZO)[1]. Recently, materials such as ITO and Zinc Iron Oxide nanocrystals have shown the ability to photodope[2,3]. This is the capacity to photo-generate – and accumulate – electric charges upon illumination. Indeed, using photons with an energy greater than the bandgap of the material, they can generate electron-hole pairs, and accumulate electrons for a long period of time[2]. These materials can be synthetized colloidally, to precisely control their dimensions and chemical composition[4]. Such synthesized nanoparticles are quite versatile materials and can be used from solution to prepare substrates to be used industrially in devices at low cost. A big challenge remains to their deposition into films with similar electrical and optical properties as their bulk counterparts. In this contribution, we focus on the study of doped metal oxide nanoparticles, from the synthesis to the tuning of opto-electronic properties. Furthermore, we will show how photodoping can affect the optical and electrochemical response both in solution and solid films. We will present the preparation of thin films from solution with the scope of integrating them in functioning devices targeting their application as electrodes for solar energy storage devices. 1. Pandey, R., Yuldashev, S., Nguyen, H. D., Jeon, H. C. & Kang, T. W. Fabrication of aluminium doped zinc oxide (AZO) transparent conductive oxide by ultrasonic spray pyrolysis. Curr. Appl. Phys. 12, S56–S58 (2012). 2. Kriegel, I. et al. Light-Driven Permanent Charge Separation across a Hybrid Zero-Dimensional/Two-Dimensional Interface. J. Phys. Chem. C 124, 8000–8007 (2020). 3. Brozek, C. K. et al. Soluble Supercapacitors: Large and Reversible Charge Storage in Colloidal Iron-Doped ZnO Nanocrystals. Nano Lett. 18, 3297–3302 (2018). 4. Ghini, M. et al. Control of electronic band profiles through depletion layer engineering in core-shell nanocrystals. (2021).

Authors : Mao Goto, Hiroto Yamagachi, Erika Saito, Yuki Tsuda, Kyota Uda, Tensho Nakamura, Atsuhiko Ueno, Tsukasa Yoshida
Affiliations : Yamagata university

Resume : Charge transfer (CT) complexes are attracting attention as light-absorbing layers that can reduce voltage loss in organic solar cells. We have discovered that a novel CT salt from deprotonated 1,3-(bisdicyanomethylidene)indan anion (TCNIH-) and methylviologen cation (MV2+). We have successfully fabricated devices by collecting microcrystals at the liquid interface and depositing them on a thin film of n-type semiconductor ZnO, and have successfully extracted CT excitons as photocurrent. However, the photocurrent extracted was very small, and this is thought to be due to a problem in carrier extraction from the microcrystals. In order to improve the affinity between the CT crystal and the carrier transport layer, hybrid thin films of p-type semiconductor CuSCN and TCNIH, MV were electrodeposited and their effect on the device properties was investigated. Potentiostatic electrolysis at an F-doped SnO2 (FTO) coated glass rotating disk electrode (RDE, ω = 500 rpm) was carried out at +0.2 V vs. Ag/AgCl. in an ethanolic solution containing 2.5 mM Copper(II) perchlorate hexahydrate, 2.5 mM Lithium Thiocyanate and 0.1 M Lithium Perchlorate served as the electrolytic bath for the electrodeposition of CuSCN, to which 1,3-(bisdicyanomethylidene)indan anion and 1,1'-Dimethyl-4,4'-bipyridinium Dichloride cation was added at 50 μM for 5 min. TCNIH toluene solution was mixed with aqueous MV solution and reacted at the water/toluene interface to accumulate TCNIH/MV CT microcrystals at the interface. When TCNIH- was added to the CuCSN deposition bath, blue thin films were obtained. The absorption spectrum of the deposited film showed absorption peaks derived from TCNIH- (620 nm). In a previous study, FLNCS hybridized with CuCSN because of the SCN group, a soft base in the HSAB rule [2]. Similarly, the soft base CN group of TCNIH is considered to act as an anchor for CuCSN, resulting in the electrodeposition of the TCNIH/CuSCN hybrid thin film. When MV2+ was added, a white thin film was electrodeposited. Dissolving the obtained film and adding a reducing agent confirmed the formation of radical cations of MV. Thus, MV2+ also formed hybrid thin films with CuCSN. The effects of the affinity between the CT layer and the hole transport layer are discussed by comparing the device properties of CT microcrystals stacked on top of electrodeposited CuCSN, CuSCN/TCNIH, and CuSCN/MV hybrid thin films. 1. E. Saito, T. Yasuhara, Y. Tanaka, R. Yamakado, S. Okada, T. Nohara, A, Masuhara, T. Yoshida, ECS Trans., 88, 301-311 (2019) 2. Y. Tsuda, K. Uda, M. Chiba, H. Sun, L. Sun, M. Schuette White, A. Masuhara T. Yoshida, Microsyst. Technol., 24, 715–723 (2018)

Authors : Andrea Rubino, Andrea Camellini, Michele Ghini, Luca Rebecchi, llka Kriegel
Affiliations : Functional Nanosystems, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova, Italy; Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Genova, Via Dodecaneso 31, 16146 Genova, Italy

Resume : In the current context of technological development, the definition of efficiency must include both optimization from an energy point of view and sustainability from an environmental point of view. Among the global strategic targets, one of the major challenges concerns the reduction of greenhouse gas emissions mainly induced by the use of fossil fuels for energy production. Solar radiation is the most promising alternative out of the various solutions for a sustainable energy supply, as an abundant, clean, renewable source of global access. For a complete de-carbonization, the technological improvement for the exploitation of solar energy deserves special attention. Nonetheless, the future industrial and commercial implementation of solar-based technology require novel advanced photoactive materials and composites in order to face energetic, environmental and economic demand. A promising way out is represented by multi-functional low dimensional materials [1,2] capable of multi-charge transfers offering new routes for energy applications and enhancing process efficiency [3]. In this work, we investigate two class of nanomaterials, in particular doped metal oxides nanocrystals [4,5] and graphenes quantum dots [6]. These materials present versatile and low-cost processability, useful for solid-state hybrid architectures, together with very attractive optical and electrical properties as for the case of the of the impressive charge accumulation in transparent semiconductor nanoparticles upon illumination [7,8]. The focus of this research concern the opportunity to access multiple-charge processes, with the prospect of the possible implementation in different devices for solar energy conversion and storage. We report the analysis of potential transfer of more than one charge carrier (electron or hole) through chemical titration of photodoped electron-rich ITO nanocrystals and modified GQDs for holes scavenging. Specific changes in the optical response of the materials subject of this study allow for the spectroscopic monitoring of the electronic state evolution. The results herein illustrated offer a new step forward in the material science for green energy-technology. References [1] Liu, R. et al. Nano Res. 2017, 10, 1545 - 1559. [2] B. Luo et al. Adv.Sci. 2017, 4, 1700104 [3] F. Wu et al. Adv. Energy Mater. 2021, 11, 2101041 [4] I. Kriegel et al. Physics Reports 2017, 674, 1–52 [5] L. Qianwen, et al. Mater. Chem. Front. 2020, 4.2, 421-436. [6] M. Ghini, et al. Nanoscale Adv. 2021, 3, 6628-6634 [7] M. Ghini, et al. Nanoscale, 2021,13, 8773-8783

15:30 COFFEE BREAK    
Advanced Characterization (II) : Mónica Burriel
Authors : Liese B. Hubrechtsen, Philippe M. Vereecken
Affiliations : Imec - Kapeldreef 75, Leuven, 3001, Belgium KU Leuven Centre for Membrane Separations, Adsorption, Catalysis, and Spectroscopy for Sustainable Solutions - Celestijnenlaan 200F, box 2454, Leuven, 3001, Belgium

Resume : One of the major challenges facing the rollout of the Internet-of-Things is the need for novel solutions to power wireless or remote sensing nodes. For these applications, strategies that harvest and convert ubiquitous energy sources such as heat into electricity would be especially advantageous. Though thermoelectrics are the most familiar approach for heat-to-electricity harvesting, these devices have relatively low temperature coefficients. This provides a stimulus for research into unconventional harvesting concepts such as the thermogalvanic effect. Thermogalvanic devices exploit the temperature dependence of the equilibrium potential of an electrochemical reaction – a property captured by the so-called thermogalvanic coefficient. These cells contain two identical electrodes in contact with a common redox electrolyte. When a temperature difference is applied over the cell, the resulting potential difference can be used to power a load. However, the spacing between the electrodes introduces an inherent trade-off between thermal and ionic conduction. As a mitigation, an alternative thermogalvanic strategy called thermally regenerative electrochemical cycles (TREC) can be used. TREC cells feature homogenous temperature distributions and two different half-reactions occurring at either electrode. Each half-reaction has its own thermogalvanic coefficient, resulting in a temperature-dependent cell potential. A TREC cell is charged and discharged at different temperatures: by discharging at a temperature where the cell potential is higher, net energy generation occurs. Thin-film Li-ion batteries could enable a new generation of high-performing and scalable TREC-based harvesters due to their low heat capacities and compact architectures. To design such devices, knowledge of the thermogalvanic coefficient of Li-ion electrodes is critically important. However, existing techniques to measure this property in Li-ion materials are not suitable as screening tools to provide reliable coefficient values for device design. We have developed a novel methodology to determine the thermogalvanic profiles of Li-ion electrodes. These profiles capture the variation of the thermogalvanic coefficient with the electrode’s lithiation state. Our approach relies on a thermogalvanic cell containing thin-film electrodes and an electrochemically-controllable lithiation state. This strategy has two advantages. On the one hand, the use of thin-film electrodes prevents thermoelectric contributions from the electrode material from influencing the thermogalvanic profile shape. Additionally, electrochemical control of the lithiation state allows to easily sample the thermogalvanic profiles with high lithiation state resolution, enabling the study of finer profile features. The methodology was validated by measuring the profile of thin-film anatase TiO2, a commonly studied Li-ion electrode material, and demonstrating it to be in excellent agreement with accepted phase behavior.

Authors : Mudasir A Yatoo and Stephen J Skinner
Affiliations : Department of Materials, Faculty of Engineering, Imperial College London Royal School of Mines, SW7 2BP, London

Resume : Storage of purified hydrogen is one of the central challenges in addressing climate change and reducing our reliance on fossil fuels for energy conversion and storage, and therefore there is a global surge in research and development concerning hydrogen purification and storage. In this regard, we are studying proton conduction in solid oxide materials at elevated temperatures for applications in hydrogen separation and compression membranes. Hydrogen compression is the most recommended method to store hydrogen for automotive applications as it allows an increase in the hydrogen volumetric energy density. Traditionally the protonic conductivity in these materials is measured by indirect methods. For example, conductivity measurements in mixed gas atmospheres, comparing for example dry N2 with humidified N2, thereby allowing the contribution of protons to be evaluated. In this study, we for the first time report the evaluation of protonic conductivity in BaZr1-xCexY0.2O3−d (BZCY) and BaZr0.1Ce0.7Y0.2–xYbxO3–d (BZCYYb) by direct measurements afforded by the Isotope Exchange Depth Profiling (IEDP) technique with deuterium labelling. We also report the kinetics of H/D transport through the bulk materials and across metal-ceramic interfaces with a particular interest in the behaviour of the interface between the key Pd/Pd alloy catalyst component and the hydrogen transporting oxide ceramic material. The transport and interface behaviour information will be significant in designing hydrogen separation and compression membranes.

Authors : Mykhailo Vorokhta1, Oleksii Bezkrovnyi2, Thu Ngan Dinhová1, Lesia Piliai1, Iva Matolinova1
Affiliations : 1. Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, 180 00, Prague 8, Czech Republic; 2. W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw, Poland;

Resume : In this work, we prepared a promising catalyst for propane oxidation composed of ruthenium supported on polycrystalline CeO2. It was found that the Ru loading on the CeO2 support strongly improves its catalytic activity, decreasing the T50 by about 200 ºC (from 500 to about 300 ºC). By utilizing several ex-situ techniques (XRD, HR-STEM, Raman spectroscopy) and in-situ NAP-XPS, we investigated the effect of different pre-treatments (calcination, reduction, and C3H8 oxidation reaction) on the morphology, structure, and chemical state of the Ru/CeO2 catalyst. The correlations between the chemical state of ruthenium in Ru/CeO2 catalyst and its activity in C3H8 oxidation receive particular attention. It is shown for the first time that the Ru/CeO2 interaction with an oxygen-rich atmosphere (C3H8+O2 (1:5)) at ≥300 °C results in ruthenium oxidation to the volatile RuO4, leading to its homogeneous dispersion inside the powder catalyst and increased catalytic activity.

Authors : A.Morata, J.C. Gonzalez-Rosillo, V. Siller, F.Chiabrera, M. Nuñez, RM. Stchakovsky, A. Tarancón,
Affiliations : (a) Department of Advanced Materials for Energy Applications, Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, 08930 Sant Adrià del Besòs, Barcelona, Spain (b) HORIBA Scientific, Avenue de la Vauve, Passage Jobin Yvon, 91120 Palaiseau, France (c) ICREA, Passeig Lluís Companys 23, 08010, Barcelona, Spain

Resume : Thin film solid-state batteries will play a prominent role as a power supply for future micro-devices. Despite this interest, there are very few commercial solutions available. Many efforts are still invested in the development of such devices with improved capabilities. The challenge is to develop appropriate electrodes with high capacity, stability and fast performance, and electrolytes with a low ionic resistance at room temperature. Furthermore, it is crucial to pay attention to the mechanical and electrochemical compatibility between the components and to provide good quality interfaces. Here we present the development of LiMn2O4 (LMO) and Li4Ti5O12 spinel electrodes, and Li1+xAlxTi2-x(PO4)3 electrolyte thin films. The materials have been deposited by means of Large Area Pulsed Laser Deposition (LA-PLD), using multi-layering routines to balance lithium content of the films. Exhaustive structural and electrochemical characterization of the layers has been carried out. In particular, recently developed operando spectroscopic ellipsometry and Raman spectroscopy techniques have been used for the study of ion-transport phenomena and the track of Lithium content and volume expansion during cycling.


No abstract for this day

Symposium organizers
Albert TARANCONCatalonia Institute for Energy Research - IREC/ICREA

Jardins de les Dones de Negre, 1, Planta 2, E-08930, Sant Adrià del Besòs, Barcelona, Spain

+34 933562615
Ilka KRIEGELFunctional Nanosystems Italian Institute of Technology

via Morego 30, 16164 Genova, Italy

Simone MELONIUniversity of Ferrara

via Luigi Borsari 46, 44121, Ferrara, Italy

+39 0532 455174

Photoactoivated Processes Unit - Avd. Ramón de la Sagra 3, 28935 Mostoles (Madrid), Spain