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Energy materials


Future electrochemical energy storage materials: from nanoscience to device integration and real environment application

The development of Electrochemical Energy Storage (EES) devices is the key challenge to face the climate change mitigation and the energy crisis for the coming years. Towards a more competitive energy markets, this Symposium will cover the main drawbacks related to the present of the EES technology as well as new findings and perspectives.


In the last decades, the EES technology has been worldwide extensively developed, allowing the successfully penetration on the market of the lithium ion-based batteries, redox flow batteries including metal air cells and supercapacitor technologies. However, those technologies suffer from several technological issues like cost, sustainability, safety, performance, and long stability. In an attempt to overcome these drawbacks, a large variety of improved nanomaterials with innovative structural and functional properties have been emerging, creating a new generation of energy storage systems. The fundamental understanding of the formation and evolution of interfaces, which leads to degradation and failure modes, is the key point behind the nanomaterial design. Additionally, novel engineering prototypes as well as in-deep evaluation in real applications are mandatory to accomplish the exigent future market requirements.

The symposium will discuss the main topics related to:

  1. High-performance materials:
    - New and economical manufacture route suitable for large scale applications
    - Improved interphase electrode/electrolyte
    - Doped materials design with innovative morphologies and porosity
    - New electrolytes formulation, additives, solid state electrolytes, water-in salt
    - Emerging chemistries with intercalation electrodes
  2. Device integration and characterization:
    - Novel cell and multi cell configuration
    - Performance optimization: operational parameters
    - Diagnosis procedures and ageing mechanism
  3. Real Application Demonstration and Economic Aspect
    - in-situ, in-operando and postmortem characterization
    - Evaluation of the performance according with the application: lifespan, efficiency
  4. Materials modeling
    - Modeling morphology and structural properties
    - Interphase studies

The symposium will share experience from interdisciplinary sectors; -industry and academic scientist -to bring an overview of the developed nanomaterials for energy storage devices. Selected papers from the symposium will be recommended by the Scientific Committee for the further consideration in the prestigious journal Electrochimica Acta.

Hot topics to be covered by the symposium:

Abstracts will be solicited in, but not necessarily limited to, the following hot topics :

  • Materials for (Photo)batteries
  • Materials and components for Redox flow batteries: liquid (i.e., metal or organic based electrolytes), semi solid electrolytes, hybrid RFB (i.e., anode materials like Li, Zn, Fe and Cu), metal-air batteries
  • Intercalation materials for post-lithium technology (i.e. Na+; Ca2+; Mg2+, Al3+ using organic electrolytes and solid electrolytes. LiS or NaS batteries
  • Materials for supercapacitadors and pseudo-capacitadors
  • Electrode/electrolyte interfaces studies
  • New electrochemical tools for characterization of devices/materials
  • Design of the cell /multi-cell: optimization operational parameter, real environment applications (i.e. electric vehicle, grid applications, household).
  • Battery/supercapacitor hybrid systems
  • Computational design
  • Modelling or “in-operando” techniques for the detection of failure mechanism: ageing mechanism
  •  Performance in real applications and economic aspects

Tentative list of invited speakers:

  • Li Yongdan (Aalto University, Finland)
  • Sebastian Fantini (Solvionic, France)
  • Alejandro Franco (Université de Picardie Jules Verne, France)
  • Fatima Montemor (Instituto Superior Tecnico, Portugal)
  • Belen Sobrido (Queen Mary University of London, UK)
  • Francesca Soavi (University of Bologna, Italy)
  • Thierry Brousse (University of Nantes, France)
  • Patrice Simon (Université Paul Sabatier, France)



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08:45 Welcome and Introduction to the Symposium    
Supercapacitor : Olivier Crosnier
Authors : Patrice SIMON
Affiliations : 1. Université Toulouse-3 Paul Sabatier, CIRIMAT Laboratory, Toulouse, France 2. RS2E, FR CNRS 3459, F-31062 Toulouse, France E-mail address:

Resume : This presentation will give an overview of the research work achieved on capacitive (porous carbon) and high-rate redox (pseudocapacitive) materials, and show the challenges/limitations associated with the development of these materials. Starting with porous carbons [1,2], we will present the state-of-the art of the fundamental of ion adsorption mechanism in porous carbons and its practical applications. Moving from double layer to high rate redox materials, we will show how the control of the material and electrode structures can help in preparing high capacitance electrodes using 2-Dimensional MXene materials in both aqueous and non-aqueous electrolytes [3-5]. In a last part, we will introduce a new in-plane electrochemical impedance spectroscopy technique based on Van der Paw measurements. These operando in-plane impedance measurements allow for the deconvolution of the ionic and electronic contributions of the total impedance at different potentials and brings new insights regarding the electronic and ionic transport mechanisms in porous electrodes during operation. This novel set-up comes as a new tool to further evaluate and improve the performance of electrode materials for energy storage devices. These results helped in developing our basic understanding of the ion fluxes at the electrolyte / material interface as well as ion interactions in confined structures. From a practical point of view, they offer new opportunities for designing high energy density electrochemical capacitors. References [1] H. Shao, Y.-C. Wu, Z. Lin, P.-L. Taberna and P. Simon, Chemical Society Reviews, 2020, 49, 3005-3039 [2] P. Simon and Y. Gogotsi, Nature Materials 19 (11), (2020) 1151-11633 [3] I. Wu et al., Angew. Chem. (2021),133,2–8. [3] B. Anasori et al., Nature Reviews Materials, vol. 2, no. 2, 2017, pp. 17. [4] X. Wang, et al., Nature Energy 4, 241–248 (2019) [5] Y. Li et al., Nature Materials (2020), 19, (2020) 894–899

Authors : Thierry Brousse1,2, Jean Le Bideau1,2 and Christophe Lethien2,3
Affiliations : 1. Institut des Matériaux Jean Rouxel (IMN), CNRS UMR 6502 – Université de Nantes, 2 rue de la Houssinière BP32229, 44322 Nantes cedex 3, France 2. Réseau sur le Stockage Electrochimique de l’Energie (RS2E), CNRS FR 3459, 33 rue Saint Leu, 80039 Amiens Cedex, France 3. Institut d’Electronique, de Microélectronique et de Nanotechnologies (IEMN), Université de Lille, CNRS, Centrale Lille, ISEN, Université de Valenciennes, UMR 8520 - IEMN, F-59000 Lille, France

Resume : The Internet of Things, enabled by a worldwide network of interconnected sensors, is limited in its large-scale deployment of nomadic miniaturized devices due to the bounds of energy self-sufficiency. One possible solution, albeit challenging, is constructing on-chip pseudocapacitive micro-supercapacitors. Herein, we achieve the collective fabrication of micro-supercapacitors based on two strategies: high capacity bi-functional electrode such as feather-like vanadium nitride films or manganese dioxide deposited onto three-dimensional microstructured silicon scaffold. The reported surface and volumetric capacitance values compete well with those of cutting-edge transition metal oxide/nitride materials, and exceed those of standard carbon electrodes. The pseudocapacitive behavior of these electrode materials in aqueous electrolytes remaining unclear. Thus, studies involving in situ/operando characterization techniques were conducted, enabling to unveil charge storage mechanisms. Moreover, solid-state like electrolytes such as ionogels were developed and enabled the fabrication of leakage-free microsupercapacitors that can sustain microelectronic fabrication processes such as solder reflow. Thus, the frontier between science and technology is never well defined when reporting on microsupercapacitors but the race for achieving high performance microdevices has been blurring the scientific investigations of micro-sized electrodes for quite a long time. Fortunately, engineering powerful electrodes involves the understanding of charge storage phenomena and of the influence of the microstructure on their electrochemical behavior.

Authors : Mathieu Deschanels(1), Marc Dietrich(2,3), Pascale Gentile(3), Saïd Sadki(2), Cristina Iojoiu(1) et Fannie Alloin(1)
Affiliations : 1) Univ. Grenoble Alpes, CNRS, Grenoble INP LEPMI, 38000 Grenoble, France (2) Univ. Grenoble Alpes, CEA, CNRS, IRIG-SyMMES, 38000 Grenoble, France (3) Université Grenoble Alpes, CEA-Grenoble, IRIG-DEPHY-PHELIQS-SINAPS, F-38000 Grenoble, France

Resume : Large-scale manufacturing of high-performance micro-supercapacitors (MSCs) is the cornerstone for the development of the next generation of miniaturized electronic devices. To be able to integrate these electrochemical devices into textiles, for example, these systems must be flexible. The development of all-solid-state systems with the use of polymer electrolyte can meet this constraint. However, these systems suffer from low power density due to the low ionic conductivity of polymer electrolytes. Polysiloxanes due to their low glass transition temperature allow a good compromise to have the possibility to develop flexible systems operating over a very wide temperature range and whose derived ionic polymer conductivities are acceptable. [1] In our study, the functionalization of polysiloxanes with different ammonium groups is performed. The decrease of the symmetry of the ammonium group allows a decrease of the glass transition temperature of the polymer. The compatibility of the polymer electrolyte with silicon nanowire electrodes has been shown by SEM image and electrochemical measurements. The first device tests seem to show a good stability of the polymer electrolyte in cycling. Reference : [1] V. Bocharova, A. P. Sokolov; J. Phys. Chem. B; 2017; 121, 11511-11519

Authors : Khac Huy Dinh (1 2 3), Kevin Robert (1 3), Florent Blanchard (2), Marielle Huvé (1 2), Pascal Roussel (1 2), Christophe Lethien (1 3 4)
Affiliations : 1 Institut d’Electronique, de Microélectronique et de Nanotechnologies, Université de Lille, CNRS, Centrale Lille, Université Polytechnique Hauts-de-France, UMR 8520 - IEMN, F-59000 Lille, France 2 Unité de Catalyse et de Chimie du Solide (UCCS), Université de Lille, CNRS, Centrale Lille, Université d’Artois, UMR 8181 – UCCS, F-59000 Lille, France 3 Réseau sur le Stockage Electrochimique de l’Energie (RS2E), CNRS FR 3459, 33 rue Saint Leu, 80039 Amiens Cedex, France 4 Institut Universitaire de France (IUF)

Resume : To power electronic devices for Internet of Things applications, obtaining high-performance electrode materials for micro-supercapacitor (MSC) is essential [1], [2]. Due to both a high electrical conductivity and an environmentally friendly behavior, transition metal nitrides (TMN) are promising candidates. Among the existing binary TMN, sputtered vanadium nitride (VN) film was recently proposed as a bi-functional material acting both as a current collector and a pseudocapacitive electrode for MSC applications [3]–[5]. Despite high surface capacitance value (~ 1.2 for 16 µm-thick VN film), VN should operate between -1 and -0.4 V vs Hg/HgO in 1M KOH aqueous electrolyte to keep the capacitance retention close to 70 % after 50 000 cycles [4], [6], validating the use of such VN films as a negative electrode. Consequently, the cell voltage is restricted to 0.6 V in a symmetric configuration, i.e. five times lower than that of electrochemical capacitors made from porous carbon-based electrodes operating in organic electrolyte (~ 3 V). To enhance the cell voltage, the design of asymmetric MSC is mandatory but the positive electrode should have similar performance than the ones of sputtered VN film to have a good balance of the charge values between the two electrodes. We recently show that asymmetric VN // RuO2 MSC can operate up to ~ 1.2 V in 1M KOH [5]. In this study, ruthenium nitride (RuN) films made from magnetron sputtering deposition method were investigated as an efficient pseudocapacitive material for positive electrode of asymmetric MSC. The electrochemical, structural and microstructural properties of RuN films were evaluated regarding the deposition parameters used in the magnetron sputtering process (pressure, gas ratio, temperature deposition and film thickness). Hence, our RuN films behave as excellent bi-functional materials for MSC electrodes, which 16 µm thick yielded high surface capacitance value close to 0.7 (or 450 in 1 M KOH aqueous electrolyte while keeping high the electrical conductivity (~ 100 For the first time, an asymmetric MSC based on sputtered RuN and VN (vanadium nitride) films, acting as positive and negative electrodes, respectively, was designed. Taking benefit of complementary working potential windows in 1 M KOH, the asymmetric VN // RuN MSC in a parallel plate configuration shows a cell voltage of 1.15 V and an energy density of 70 µ at power density of 1 REFERENCES: [1] C. Lethien, J. Le Bideau, and T. Brousse, “Challenges and prospects of 3D micro-supercapacitors for powering the internet of things,” Energy Environ. Sci., vol. 12, no. 1, pp. 96–115, 2019, doi: 10.1039/c8ee02029a. [2] N. A. Kyeremateng, T. Brousse, and D. Pech, “Microsupercapacitors as miniaturized energy-storage components for on-chip electronics,” Nat. Nanotechnol., vol. 12, no. 1, pp. 7–15, 2017, doi: 10.1038/nnano.2016.196. [3] K. Robert et al., “On Chip Interdigitated Micro-Supercapacitors Based on Sputtered Bifunctional Vanadium Nitride Thin Films with Finely Tuned Inter- and Intracolumnar Porosities,” Adv. Mater. Technol., vol. 3, no. 7, pp. 1–12, 2018, doi: 10.1002/admt.201800036. [4] K. Robert et al., “Novel insights into the charge storage mechanism in pseudocapacitive vanadium nitride thick films for high-performance on-chip micro-supercapacitors,” Energy Environ. Sci., vol. 13, no. 3, pp. 949–957, 2020, doi: 10.1039/c9ee03787j. [5] B. Asbani, K. Robert, P. Roussel, T. Brousse, and C. Lethien, “Asymmetric micro-supercapacitors based on electrodeposited Ruo2 and sputtered VN films,” Energy Storage Mater., vol. 37, no. February, pp. 207–214, 2021, doi: 10.1016/j.ensm.2021.02.006. [6] A. Morel, Y. Borjon-Piron, R. L. Porto, T. Brousse, and D. Bélanger, “Suitable Conditions for the Use of Vanadium Nitride as an Electrode for Electrochemical Capacitor,” J. Electrochem. Soc., vol. 163, no. 6, pp. A1077–A1082, 2016, doi: 10.1149/2.1221606jes.

10:30 Discussion    
10:45 Break    
Authors : Sakeb Hasan Choudhury, Guillaume Vignaud, Botayna Bounor, Jensheer Shamsudeen Seenath, Pascal Dubreuil, David Bourrier and David Pech
Affiliations : Sakeb Hasan Choudhury: Botayna Bounor: Jensheer Shamsudeen Seenath: Pascal Dubreuil: David Bourrier: and David Pech LAAS-CNRS, Université de Toulouse, CNRS, 7 avenue du colonel Roche, Toulouse 31400, France. Guillaume Vignaud Université Bretagne Sud, 2 rue Coat Saint-Haouen, BP 92116 Lorient, France

Resume : The application of independent autonomous microelectronic devices has revolutionized the IoT (Internet of Things) based industry [1]. Therefore, the development of on-board micro energy storage has become one of hot research topics in scientific community. In recent years, it was evident that the 3D micro supercapacitors are shaping up to be capable of serving such purposes. One of the remarkable aspects of 3D micro supercapacitors was the emergence of dynamic hydrogen bubble template (DHBT). It provided the necessary 3D architectures of micro supercapacitors for satisfying the energy storage requirements of high-power on-board devices. However, the efficient utilization of this highly porous DHBT structures still remains a challenge when it comes to coat them with active materials [2]. Here, in this work we represent the Atomic Layer Deposition (ALD) approach to handle such challenges. ALD is considered as a deposition method capable of depositing materials conformally on intricate and porous surfaces. To investigate the scheme, we propose to deposit a hydrous RuO2.xH2O as the active materials on DHBT samples. In order to examine the stable ALD growth, we used Ru(EtCp)2 and O2 as precursors on flat Au and Pt substrates primarily [3]. Afterwards, the DHBT samples were subjected to ALD RuOx process. The temperature for ALD deposition was kept at 200°C to avoid losing electrochemical area of the DHBT samples. From our initial experiments, we observed that capacitance value of 7 mF cm-2 can be achieved from 500 ALD cycles of RuOx on an Au DHBT template. To optimize the performance, an electrochemical oxidation needs to be performed on the as-deposited ALD RuOx [4]. We assume that the electrochemical oxidation promotes the hydrous nature of ALD deposited RuOx. [1] N.A. Kyeremateng, T. Brousse, D. Pech, Microsupercapacitors as miniaturized energy-storage components for on-chip electronics, Nat. Nanotechnol. 12 (2017) 7–15, [2] A. Ferris, D. Bourrier, S. Garbarino, D. Guay, D. Pech, 3D interdigitated microsupercapacitors with record areal cell capacitance, Small 15 (2019) 1901224, [3] S Park, W Kim, W. Maeng, Y. Yang, C. Park, H Kim, K Lee, S Jung, W. Seong, 3D interdigitated microsupercapacitors with record areal cell capacitance, Thin Solid Films 516 (2008) 7345, [4] R. Warren, F. Sammoura, F. Tounsi, M. Sanghadasa and L. Lin, Highly active ruthenium oxide coating via ALD and electrochemical activation in supercapacitor applications, J. Mater. Chem. A, 3 (2015) 15568,

Authors : Maciej Tobis*(1), Anetta Płatek-Mielczarek(1), Justyna Piwek(1), Łukasz Przypis(2), Dawid Janas(2), Elżbieta Frąckowiak(1)
Affiliations : (1) Poznan University of Technology, Institute of Chemistry and Technical Electrochemistry, 60 – 965 Poznań, Berdychowo 4, Poland, (2) Silesian University of Technology, Faculty of Chemistry, 44 – 100 Gliwice, B. Krzywoustego 4, Poland * lead presenter

Resume : Electrochemical capacitors (ECs) are high-power energy storage systems, which gather significant attention from researchers in the era of device miniaturization. The principal mechanism of charge storage is based on the ion reversible electrostatic attraction at the electrode/electrolyte interface. Therefore, the ideal electrode material should possess well-developed specific surface area and high conductivity. Carbonaceous materials, e.g., activated carbons meet these criteria and are able to provide high capacitance and high charge/discharge rates. However, despite many positive aspects of these systems, one major drawback is low-energy density which excludes ECs from the competition with metal-ion batteries. To increase their specific energy density, it is possible to incorporate a redox component in the electrode material or in the electrolytic solution. It has been already demonstrated that the use of halogen salts (e.g., iodides or bromides) as an additive to the electrolyte or electrolyte itself improves the overall performance of the ECs by exhibiting reversible faradaic reactions. However, the influence of different forms of iodine incorporated in carbon framework has never been explored in ECs response. Very recently, it was found that the iodonium salts (e.g., pyridine iodine monochloride) can be successfully employed as doping agents. They are also able to tailor the electronic properties of nanocarbon materials such as single-walled carbon nanotubes (SWCNTs). Iodonium salts can contribute to the overall amount of charge stored by exhibition of redox reactions, while simultaneously increasing the conductivity of the electrode material. In this work, we explore the effect of iodonium salts as doping agents for SWCNT-based capacitors. Thin film electrodes from SWCNTs were soaked with selected iodonium salts dissolved in methanol and dried. Then, such materials were assembled in symmetrical and asymmetrical EC systems. The electrochemical performance of the prepared cells was studied in neutral electrolytes (sulphates and iodides) by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. Different techniques such as nitrogen adsorption-desorption at 77K, Raman spectroscopy, and Scanning Electron Microscopy were chosen for structural and textural properties characterization. An asymmetric system with activated carbon as the negative electrode in 1 mol L-1 KI exhibited a three-fold higher specific capacitance compared to symmetric one containing only SWCNTs. It was proven that the tandem application of iodonium salt and redox-active electrolyte in ECs may significantly enhance specific capacitance and offer high power rate retention. Acknowledgements: The authors would like to acknowledge the National Science Centre, Poland, for the financial support in the framework of the project 2018/31/B/ST4/01852.

Authors : Miguel Granados-Moreno*(1)(2), Gelines Moreno-Fernández(1), Rosalía Cid(1), Juan Luis Gómez Urbano(1)(2) and Daniel Carriazo(1)(3).
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)Universidad del País Vasco, UPV/EHU, 48080 Bilbao, Spain (3)IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain

Resume : Lithium-ion capacitors (LICs) comprising a battery-type and a capacitor-type electrode have emerged in the energy storage field in order to overcome the main limitations of batteries (i.e., low power density output) and electrochemical double layer capacitors (i.e., low energy density output) [1]. Graphene has shown potential use for LICs, since it can be used both for battery-type and capacitor-type electrodes[2]. In this work, a microstructured nitrogen-doped graphene decorated with Sn submicrometer-sized particles has been successfully developed by a single-step synthesis. The nitrogen doping made on to the negative electrode induces topological defects that can offer extra Li storage sites and enhance electronic conductivity. The excellent features of the nitrogen-doped graphene matrix combined with the homogeneous distribution and high theoretical capacity (994 mA·h·g-1) of the submicrometer-sized Sn particles, allows developing a negative electrode able to arise high capacity outputs even at fast charge/discharge rates. This material is later incorporated as the battery-type electrode of the developed LIC. For the capacitor-type electrode, an activated carbon derived from the pyrolysis of a graphene-carbon composite was synthetized. The flat-shaped morphology, large surface area and proper pore size distribution that it presents, enhances the double-layer formation. The developed LIC was optimized by means of selecting the best mass ratio between the positive and negative electrode, which turns out to be 2:1. This system allows to deliver high energy and power values of 133 W·h·kg-1 at 142 W·h·kg-1 and 51 W·kg-1 at 25,600 W·kg-1 (per mass of active material, AM). Moreover, it also shows very long cycle life, reaching 19,000 cycles with 100% capacitance retention, while delivering 100 W·h·kg-1 at 5,600 W·kg-1, becoming one of the best values reported for Sn-based LICs and being comparable to the cycle life of EDLCs [3], [4] [1] B. Babu et al., Adv. Energ. Mat., 10 (29) 2001128, 2020 [2] C. Li et al., J. Phys. D. Appl. Phys., 52 (14), 143001, 2019 [3] F. Sun et al., Sci. Rep., 7 (1), 40990, 2017 [4] J. Ajuria et al., J. Power Sources, 363, 422–427, 2017

11:45 Discussion    
12:00 LUNCH    
Authors : Joyanti Halder, Ananya Chowdhury, Puja De, Sakshi Kansal, Surbhi Priya, Amreesh Chandra
Affiliations : Indian Institute of Technology, Kharagpur, Department of Physics; Indian Institute of Technology, Kharagpur, Department of Physics; Indian Institute of Technology, Kharagpur, Department of Physics; Indian Institute of Technology, Kharagpur, School of energy science and engineering; Indian Institute of Technology, Kharagpur, School of energy science and Engineering; Indian Institute of Technology, Kharagpur, Department of Physics

Resume : The performance of supercapacitors under the external magnetic field has become an interesting and new field of interest. For the last few decades, this particular field remained almost ignored. But, very recently, it was reported that the external magnetic field can affect the electrochemical performance of magnetic metal oxide based electrodes like Fe2O3, NiO, Co3O4, etc. The improvement in the charge storage performance under an external magnetic field has been attributed to the modulation in the diffusion behavior of the electrolyte ions near the surface electrolyte interface (SEI). Also, the magnetohydrodynamic (MHD) effect is responsible for performance alteration as it reduces the Nernst layer and enhances the limiting current. Although there was a number of investigation on magnetic metal oxides like NiO and Fe2O3, no such study was reported till now where two magnetic metal oxides are present in the same electrode material in a composite form. In this work, the synergistic effect of two magnetic elements for inducing significant enhancement in the electrochemical activity of composite electrode material has been established. A solid sphere of α-Fe2O3 was synthesized using a simple hydrothermal route. Further, it's composite with another magnetic metal oxide viz., NiO was formed using a simple ex-situ path. The composite showed better electrochemical performance with a specific capacitance of 86 F g-1 at 1 A g-1 current density whereas the single metal oxide i.e. α-Fe2O3 possessed a value of 50 F g-1 under similar conditions. Under external magnetic field, both α-Fe2O3 and Fe2O3@NiO showed nearly 3 times higher specific capacitances. Further, a theoretical model has been established and being reported to explain the change of diffusion behavior of the electrolyte ions under the action of external magnetic fields. A correlation between the specific capacitance and the diffusion coefficient values of the electrolyte ions has been established to prove the synergistic effect of two magnetic elements in the corresponding electrochemical activity.

Authors : Nilanka M. Keppetipola* (1), G. R. A Kumara (2), Marie-Anne Dourges (1), Céline Olivier (1), Thierry Toupance (1), Ludmila Cojocaru (1)
Affiliations : (1) The University of Bordeaux, Institute of the Molecular Science, 351 Cours de la Libération F-33405 Talence Cedex, France (2) National Institute of Fundamental Studies, Hantana Road, 20000 Kandy, Sri Lanka

Resume : As a promising clean energy generation technology, solar cells have attracted much more attention to meet the rising global energy demand. However, the main drawback of intermittency of solar irradiation limits the continuous power generation which can be overcome with the use of storage devices to keep continuous power delivery in the dark. Currently, the devices with this dual functionality named photo-supercapacitors, are receiving increasing attention, specifically hybrid solar cells such as dye-sensitized or perovskite solar cells integrated with storage devices in a single system.[1] Among the storage devices, supercapacitors show favorable properties for direct integration with solar cells due to their quick charging abilities and long cycle life. In this work, supercapacitor electrodes were fabricated using activated carbon produced through an environmentally friendly activated carbon synthesis approach and easily accessible coconut shells waste as raw material. Two simple synthetic routes were carried out with different sizes of carbonized coconut shell particles and activation times via water and steam as activating agents. Characterization studies from X-ray diffraction (XRD) and Raman spectroscopy confirmed the graphite type carbons with higher disordered nature for those prepared by steam activation. Moreover, N2 sorption studies showed a range of Brunauer–Emmett–Teller (BET) surface area from 539 to 1998 m2 g-1 with the total pore volume of 0.22 to 1.09 cm3 g-1 respectively. More importantly, the activated carbon sample with the highest surface area (1998 m2 g-1) and total pore volume (1.09 cm3 g-1) prepared by steam activation showed significant storage ability as electrode material in supercapacitors. The assembled device using this activated carbon as electrodes in combination with ionic liquid (1-methyl-1-propyl-pyrrolidinium bis(fluorosulfonyl)imide) as electrolyte, under 3.5 V working potential, exhibits remarkable capacitance of 219.4 F g-1 at the scan rate of 1 A g−1. Moreover, this device showed low internal resistance of 4.3  and high specific energy of 92.1 W h kg−1 and power density of 2046.9 W kg−1.[2] This device was able to maintain its high energy values at 30 A g−1 indicating its potential to be applied in high energy and power-related applications and be integrated with solar cells. To the best of our knowledge, these are the best performances reported so far for ionic liquid-based supercapacitors with activated carbon obtained from biomass wastes and there are no examples in the literature of photo-supercapacitors using biomass as a source of activated carbon in an integrated compact system with perovskite solar cells. References: 1. N. M. Keppetipola, et al., Sustainable Energy Fuels, 2021, 5, 4784-4806. 2. N. M. Keppetipola, et al., RSC Advances, 2021, 11(5), 2854-2865.

14:45 Discussion    
Poster Session 1 - Electrodes for energy storage : Cristina Flox
Authors : Farjana J. Sonia*, Golam Haider, Martin Müller, Milan Bousa, Antonín Fejfar, Martin Kalbáč, Otakar Frank
Affiliations : Farjana J. Sonia; Golam Haider; Milan Bousa; Martin Kalbáč; Otakar Frank - J. Heyrovsky Institute of Physical Chemistry of the AS CR, v.v.i., Dolejskova 2155/3, 182 23 Prague 8, Czech Republic; Martin Müller; Antonín Fejfar - FZU-Institute of Physics of the Czech Academy of Sciences, 16200 Prague 6, Czech Republic

Resume : Energy storage devices are especially important for the fields of portable electronics and energy processes related to renewable energy generation and its application. Li-ion battery has become an excellent energy storage solution for a wide range of applications because of its multi-fold advantages i.e., high energy and power density, high working potential, long lifetime, etc. However, to fulfill the ever-increasing demand for energy, long cyclic performance, and safety of Li-ion batteries, exploring new and more efficient electrode materials has been stressed in recent years. Silicon is considered the most promising substitute of the commonly used graphitic carbon anode material due to very high theoretical Li-storage capacity, earth abundance, and better safety aspects. However, severe volume expansion/contraction upon lithiation/delithiation and hence pulverization from the current collector, poor electrical conductivity, unstable solid electrolyte interface layer, etc. are the major problems of Si anode that hinder the practical application of Si in Li-ion battery. In the current report, an attempt is made to address these issues by introducing few-layer graphene (Gr) with Si. The Si/Gr composite is engineered in such a way that the electrode possesses a porous structure providing Si enough space to expand/contract during Li-intake/uptake. Additionally, graphene acts here as a strong backbone to Si and provides a smooth electronic conduction path so that Si can withstand volume expansion, sustain more lithiation/delithiation cycles and also provide high power density. The thus prepared Si/Gr composite electrodes have shown excellent rate capability and cyclic stability. The reversible capacity obtained with Si/Gr is ~2100mAh/g at the current rate of C/5 even after 200 cycles. Furthermore, ~1500mAh/g reversible capacity is obtained with Si/Gr at a much higher current rate of 20C which is twice that obtained with Si thin film (of similar thickness as in the Si/Gr composite) without Gr buffer layer.

Authors : E.I.Ionete1 , S.M. Iordache2 ,3, A.M. Iordache2 ,3, I. Stamatin3, E. Tanasa4, V. Barna5, I. C.Vasiliu2, M.Elisa2, I. Chilibon2, S. Caramizoiu3,6, C.E.A. Grigorescu2
Affiliations : 1National R&D Institute for Cryogenics and Isotopic Technologies – ICSI Rm.Valcea, 4 Uzinei Str. RM Valcea, 240050, Valcea, Romania. 2National Institute for Research and Development in Optoelectronics-INOE 2000,Optospintronics Department, 409 Atomistilor, 077125, Magurele Romania 3University of Bucharest, Faculty of Physics, 3Nano-SAE Research Center, 405 Atomistilor, P.O. Box MG-38, 077125, Magurele, Romania. 4Politehnica University of Bucharest, 313 Splaiul Independenței, Bucharest, Romania. 5University of Bucharest, Faculty of Physics, 405 Atomistilor, 077125, Magurele, Romania 6National Institute for R&D in Microtechnologies IMT-Bucharest, 126A Erou Iancu Nicolae Str., Voluntari, 077190, Romania

Resume : Abstract Carbon nanotubes were functionalized with Cs nanoparticles via reverse micelle. For the synthesis route, we used single-step synthesis by preparing three solutions (a solution containing the metal ion, one containing the reducing agent and the third one containing the MWCNT-support solution) which were mixed in an ultrasound processor and allowed to react at room temperature for 12 hours. After this time, the solid phase separates and the precipitate is decanted and washed with acetone. The electrochemical characterization (cyclic voltammetry and EIS) of the material was performed in acidic low-deuterium water (Qlarivia®, concentration of deuterium ≤25 ppm). The micellization process is a simple and highly efficient approach to successfully synthesize metallic nanoparticles, while the electrochemical investigations show promising results in energy storage. Keywords: cyclic voltammetry, electrochemical impedance, functionalized carbon nanotubes Acknowledgements: 87PD/2020, 393PED/2020, 18/N/2019, 18PFE/30.12.2021

Authors : H. Ghannam*(1,2), O.Elkhouja (1,3), T. Tite (1), C. Ungureanu(4), M. Buga(4), A. A. Zaulet(4), E. Matei(1), C. C. Negrilă(1), A.C. Galca(1), G. Stan(1), A. Chahboun(2)
Affiliations : (1) National Institute of Materials Physics, RO-077125 Magurele, Romania (2) Abdelmalek Essaadi University, FSTT, Thin Films and Nanomaterials Lab., 90000 Tangier, Morocco (3)Laboratory of Materials and Subatomic Physics, Faculty of Sciences, Ibn Tofail University, Campus Universitaire, 14000 Kenitra, Morocco (4) National Research and Development Institute for Cryogenics and Isotopic Technologies - ICSI Rm. Valcea, Uzinei Street no. 4, PO Box Râureni 7, 240050, Râmnicu Vâlcea, Romania

Resume : The increased demand for autonomous and miniaturized energy storage devices (ESDs) has stimulated an intense interest in the research community to identify ways to improve the anodes and cathodes in rechargeable Li-ion batteries and supercapacitors. Alternatively, in concomitance a recent trend aims to develop ESDs with less lithium or beyond Li technology (e.g. Sodium). Transition-metal oxides (TMO) (e.g. V2O5, Co3O4, ZnO) and hydroxide materials (e.g. Ni(OH)2, Co(OH)2), have been considered as the most promising materials electrode for batteries and capacitors due to their unique physico-chemical properties [1]. Indeed, transition metal oxides /hydroxides provide one of greatest range of forms. They can grow in one, two and three-dimensional forms allowing for higher electro-active surface, short pathways, and high kinetics for lithium ion insertion/extraction. On the other hand, transition-metal oxides/hydroxide materials provided synergic properties through their faradaic contribution. In this context, the employment of nanosized and nanostructured TMO could provide new strategies for achieving ESDs with higher energy density and better cycling stability [1]. The development of CoO and Co3O4 nanostructures is appealing by the possibility of an effective cycling performance at low voltages and a capacity between 640-700 mA.h.g–1 in the voltage interval exceeding from 3.0 to 0 V, [1,2]. In the present work, porous cobalt oxide films have been electrodeposited by chronoamperometry from an aqueous solution of 0.1 M Co(NO3)2.6H2O on aluminium-graphene foil and nickel foam. The obtained deposits were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy, X-ray diffraction measurements (XRD), and Raman spectroscopy. SEM shows porous structures consisting of many interlaced sheets. Raman analysis and XRD patterns have confirmed the formation of Co3O4 nanostructures after the thermal treatment of the electrodeposited film. Raman spectroscopy spectra revealed the most intense characteristic band corresponding to stretching mode of spinel Co3O4 (A1g symmetry vibrational mode). The electrochemical properties have been investigated by cyclic voltammetry, electrochemical impedance spectra and galvanostatic charge/discharge in different electrolyte (e.g. LiCl, Na2SO4). The effect of Co3O4 deposit on different substrate on the electrochemical performance were systematically studied. The results indicate an improvement of the electrochemical performance of Co3O4 on aluminum –graphene foil. This improvement is related to synergic properties provided from the electrical double layer (EDL) capacitance of graphene and the faradaic contribution of Co3O4. [1] Yao et al., Journal of Alloys and Compounds 521 (2012) 95– 100 [2] Fang et al., Adv. Energy Mater. 2020, 10, 1902485

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Electrolytes for batteries : Olivier Crosnier
Authors : Sébastien FANTINI, Rongying LIN, Anaïs FALGAYRAT, Pauline RULLIERE, Pierre-Alexandre MARTIN, Tom GOUVEIA, François MALBOSC
Affiliations : Solvionic SA, Chemin de la Loge, CS 27813, Toulouse, 31078, France

Resume : Electrolyte optimization is requested to improve next generation batteries in terms of performance, including cell cyclability, rate capability, safety, and lifespan. In this presentation we will present the strategic key points of ionic liquid based electrolytes production and R&I to achieve commercialization goals and meet the expectation of battery manufacturers: purity, process and scale-up, low production cost.

Authors : Palumbo, O. (1), Sarra, A. (1), Cimini, A.(1), Brutti. S. (1,2), Appetecchi, G.B.(3), Simonetti, E.(3), Maresca, G.(3), Fantini, S.(4), Lin, R.(4), Falgayrat, A.(4), Paolone, A.(1).
Affiliations : (1) Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi,Piazzale Aldo Moro 5, 00185 Rome, Italy (2) Sapienza University of Rome, Department of Chemistry, Piazzale Aldo Moro 5, 00185 Rome, Italy (3) Agenzia Nazionale per le Nuove Tecnologie, l’Energia e lo Sviluppo Economico Sostenibile (ENEA), Materials and Physicochemical Processes Technical Unit (SSPT-PROMAS- MATPRO), Via Anguillarese 301, 00123 Rome, Italy (4) Solvionic SA, 11 Chemin des Silos, 31100 Toulouse, France

Resume : Ionic liquid (ILs) electrolytes based on imidazolium and tetra-alkyl-ammonium cations, coupled with bis(perfluroalkylsulfonyl) imide anions have been specifically tailored for lithium batteries operating up to ~5 V in the framework of the Si-Drive H2020 Project, obtaining satisfying ion transport and electrochemical properties. Here, we present the full characterization of their physical properties paying attention to the effect of temperature and lithium salt incorporation, as well as to the nature of the cation. The thermal stability is studied by means of themomogravimetry showing that the liquids with the bis(fluorosulfonyl)imide (FSI) anion decompose at temperatures lower than those based on the bis(trifluoromethylsulfonyl)imide (TFSI). Moreover, their vapor pressures are measured by isothermal heating. Infrared spectroscopy exploiting both MIR and FIR frequency range, coupled with DFT calculation, is used to obtain information about the interactions between anion and cation and the possible occurrence of conformational disorder. Indeed, all the properties of ILs are the consequence of competitive microscopic interaction forces; therefore, the knowledge of the microscopic properties and of the intermolecular forces is fundamental to allow the design of ILs with specific macroscopic properties. The reported results, besides showing that the properties of the proposed liquids are well suitable for their use as electrolytes, provide insights into the close relation between intermolecular interactions and conformational disorder. In particular the data obtained for two ILs having ethoxy containing tetra-alkyl-ammonium cations highlight the importance of the interplay between conformational disorder and acidity/polarization of the possible hydrogen bonds behind the determination of the macroscopic properties of the ILs.

Authors : Michele A. Salvador, Elena Degoli, Alice Ruini, Rita Magri
Affiliations : University of Modena and Reggio Emilia; University of Modena and Reggio Emilia; University of Modena and Reggio Emilia; University of Modena and Reggio Emilia; University of Modena and Reggio Emilia

Resume : Ionic liquids have been proposed to constitute electrolyte solutions that improve the performance of Li-ion batteries, due to their particular properties, especially conductivity. In this work, classical molecular dynamics simulations were used to study the structural and dynamic properties of electrolyte solutions, based on ionic liquids and with different amounts of lithium. Pyrrolidinium cations with small linear chains 1-methyl-1-ethyl pyrrolidinium (Pyr12) and 1-butyl-1-butyl pyrrolidinium (Pyr14) were combined with anions hexafluorophosphate (PF6) and tetrafluoroborate (BF4) to build the pure ionic liquid models, while a fraction of the pyrrolidinium cations were replaced (1:1 proportion) by lithium (Li) cations to form the electrolyte solutions with different fractions of lithium. OPLS-based forcefield parameters as implemented in Gromacs software were used to model the intramolecular and intermolecular interactions of all the species, and all the properties were obtained from a 20 ns production phase with NPT ensemble at 400 K temperature and 1 bar pressure. Our results show that the density of systems with PF6 anions is larger than that of the systems with BF4, for all fractions of lithium. Also, for the four ionic liquids considered, the density decreased almost linearly with the increasing amount of lithium, except for the Li-anion systems (i.e., without pyrrolidinium). We have obtained interesting trends also for the behavior of the pair correlation function (g(r)) analyzes and for the cation and anion self-diffusion. Our results show that for systems without lithium, the cations diffuse differently in each ionic liquid, although the systems with the same anion have closer values of cation self-diffusion. Anion self-diffusion depends on the anion species. Lithium diffusion is larger in Pyr12-anion systems, with a 0.25 lithium fraction, and BF4 anions. It is important to point out that the lithium diffusion in the ionic liquid is smaller than the diffusion of other ionic species, as reported in the literature. Our results are of interest for the engineering of new ionic liquid based electrolytes for the batteries of the next generation. This research was developed under the framework of the BAT4EVER project ( that has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 957225.

Authors : Cluzeau Benoît, Dedryvere Rémi, Dumont Erwan, Gillot Stephane, Jordy Christian, Pavlenko Ekaterina
Affiliations : IPREM laboratory; IPREM laboratory; Saft compagny; Saft compagny; Saft Compagny; Saft compagny.

Resume : Li-ion batteries have reached great importance in the last decades as power sources of portable devices such as cell phones, laptop computers and others. However, some safety problems like electrolyte leakage or fire, that constitute a bottleneck for future applications, have been reported from these types of batteries. Most of these problems come from the use of a highly flammable liquid electrolyte. An ideal solution would be to use a solid polymer electrolyte (SPE), which is solvent free and non-flammable. But SPEs exhibit low ionic conductivity and large interfacial resistance at room temperature (RT). To combine good properties of liquid and polymer electrolytes, the gel polymer electrolyte (GPE) concept has been introduced. GPEs display high ionic conductivity and good interfacial contact at RT. In addition, in-situ polymerization presents an easy assembly process compatible with the conventional Li-ion fabrication equipment In this work, we report on a GPE based on poly (ethylene glycol diacrylate) (PEGDA) as polymer matrix coupled with a liquid phase, mostly composed of a non-flammable solvent. The mechanical properties can be tuned by changing the polymer-to-liquid weight ratio. Good results in terms of ionic conductivity, electrochemical stability and safety suggest it is suitable for Li-ion batteries. As a confirmation, NMC and graphite electrode with high loading were used to prepare 100 mAh pouch cells. After studying polymer distribution in the electrode, electrochemical testing revealed a very good capacity retention (>80% after 350 cycles).

Authors : Jun Deng, Kazunori Nishio, Yuki Watanabe, Kurei Edamura, Ryota Shimizu, and Taro Hitosugi
Affiliations : Tokyo Institute of Technology, Japan

Resume : Ionic liquids (ILs) are attractive candidates as electrolytes for Li-ion batteries (LIBs) due to their high ionic conductivity, wide electrochemical potential window, and nonflammability. For further development of the LIBs using ILs, it is critical to design the interface of ILs and positive electrodes with electrochemically robust and low resistance. However, the mechanism of Li-ion transport at the interface is not well known. Therefore, in this study, we investigated the interface resistance quantitatively by utilizing a LiCoO2(001) epitaxial thin film as a positive electrode and tetraglyme-lithium bis(trifluoromethanesulfonyl)imide equimolar complex, [LiG4][TFSA], as IL electrolyte. For the characterization of battery performance, a three-electrode type battery cell was prepared, consisting of the LiCoO2(001) film and Li foils as working and reference/counter electrodes. The three electrodes were immersed into [LiG4][TFSA] ionic liquid. Cyclic voltammetry (CV) was performed to test battery operation. Electrochemical impedance spectroscopy was used to evaluate the interface resistance. In CV curves, oxidation and reduction reaction current peaks are observed at 3.93 and 3.86 V vs. Li/Li in the first CV cycle. After the first CV cycle, the interface resistance at [LiG4][TFSA] LiCoO2(001) is 268 Ωcm2. However, as CV cycles increase, the difference between the oxidative and reduction current peaks is enlarged, meaning the deteriorated battery performance. This result originates from the increase in the interface resistance, which is 82 times greater (21,780 Ωcm2) after ten CV cycles than after the first CV cycle. In contrast, we succeeded in stable battery performance by introducing a Li3PO4 film with a thickness of 20 nm at the [LiG4][TFSA]–LiCoO2(001) interface. As a result, introducing the Li3PO4 film leads to overlapping CV curves even after ten cycles. In addition, no significant increase in the interface resistance is confirmed after the CV cycling. The results highlight the importance of the interfacial modification at IL and positive electrode to improve battery performance.

10:30 Discussion    
Authors : M. F. Montemor
Affiliations : Centro de Química Estrutural, Institute of Molecular Sciences, Departamento de Engenharia Química Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1049 001 Lisboa, Portugal

Resume : The energetic transition is raising countless applications that require electrochemical energy storage solutions. Batteries and supercapacitors are the main players, being used in distinct applications since their metrics are quite different. Batteries provide high energy density, while supercapacitors are excellent to manage high power demand and short time of responses. Despite the importance of these devices there is still a gap, concerning applications that may require metrics that do not match well with the response of batteries or conventional supercapacitors. In this frame, asymmetric supercapacitors (and ultra batteries) combining a battery type electrode and a supercapacitive carbon electrode have been reported. However, they still suffer of modest energy density and important capacity fade under cycling. Thus, despite important advances there are still many open challenges to better tailor the metrics of these devices and to ensure enhanced performance in practical applications. The development of new electrode material compositions, combining pseudocapacitive (fast redox redox) materials and carbon based materials in the same electrode, appears as a very promising strategy to enhance energy density and to keep high power rate. This is particularly attractive to develop new supercapacitor devices capable of storing higher energy density at high power density. This talk overviews recent advances on the development of composite materials, combining both carbon based materials and redox metal compounds to enhance the capacitance of the electrodes in aqueous and environmentally friendly electrolytes. The main target is to create compositions that can tailor the electrodes metrics, creating fit for the purpose devices, capable of delivering higher energy density at high power. Aknowledgments: The author acknowledges Funding drom Fundação para a Ciência e Tecnologia (FCT) for the projects: CQE - UIDB/00100/2020, UIDP/00100/2020, LA/P/0056/2020 and PTDC/QUI-ELT/2075/2020

Authors : N. Carboni,(a) S. Brutti,(a),(b),(c) O. Palumbo,(a) G.B. Appetecchi,(d) G. Maresca,(d) H. Geaney,(e) K. M. Ryan,(e) F. Capitani,(f) S. Fantini,(g) R. Lin,(g) P.-A. Martin,(g) A. Paolone(a)
Affiliations : (a) ISC-CNR, UOS Sapienza, Piazzale A. Moro 5, 00185 Roma (IT); (b) Dip. Chimica Un. Roma La Sapienza, P.le Aldo Moro 5, 00185 Roma (IT); (c) GISEL—Centro di Riferimento Nazionale per i Sistemi di Accumulo Elettrochimico di Energia, INSTM, via G. Giusti 9, 50121 Firenze (IT); (d) ENEA, Materials and Physicochemical Processes Technical Unit (SSPT-PROMAS- MATPRO), Via Anguillarese 301, 00123 Roma (IT); (e) Department of Chemical Sciences, University of Limerick (IE); (f) Synchrotron Soleil, BP 48, 91192 Gif-sur-Yvette (FR); (g) SOLVIONIC, 11 Chemin des Silos, 31100 Toulose (FR)

Resume : The improvement of the performances of Lithium-Ion Batteries (LIBs) is one of the hot topics for energy storage. LIBs are, currently, the state-of-art energy storage systems in terms of energy density, duration and efficiency(1). To pursue a wider market penetration of hybrid or all-electric vehicles, innovations are needed in the battery formulations regarding all the active components: positive and negative electrodes as well as electrolytes. The aim of the Si-DRIVE projectis to develop a new generation LIB using a Silicon negative electrode, an ionic liquid-based (IL) electrolyte and a Cobalt free Lithium Rich Oxide positive electrode. In this work, we analysed the morphology and the composition of the solid electrolyte interphase (SEI) layer precipitated on the carbon free self-standing amorphous Silicon (a-Si) electrodes during galvanostatic cycling in an electrochemical cell. Various experimental techniques, such as Attenuated Total Reflectance (ATR), Raman, Optical Photothermal IR Spectroscopy (OPTIR) and Scanning Electron Microscopy (SEM) were employed. We used either a lithium bis(fluorosulphonyl) imide/ethyl methyl imidazolium bis(fluorosulphonyl) imide or a lithium bis(trifluoromethyl sulphonyl) imide/ethyl methyl imidazolium bis(fluorosulphonyl) imide based electrolyte. The use of this ionic liquid as solvent discloses a unique combination of promising electrochemical performance and enhanced safety. The aim of this study is to verify the impact of this innovative electrolyte on the chemical nature and morphological properties of the SEI layer over the high-capacity silicon electrode. This Project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 814464. (1) M. Stanley Whittingham, Chem. Rev. 2014, 114 (23), 11413

Authors : A. Hardy, J. Mercken, A.-S. Kelchtermans, B. Joos, D. De Sloovere, M.K. Van Bael
Affiliations : UHasselt, Institute for Materials Research, imec division imomec, Energyville, Agoralaan building D, 3590 Diepenbeek, Belgium

Resume : Ionogels, in which an ionic liquid (IL) is confined within a silica matrix, are attractive hybrid solid electrolytes for lithium ion batteries (LIBs) because of their sufficiently high ionic conductivity, high thermal stability, and broad electrochemical stability window. However, several other properties remain to be improved. Ionic liquids are often considered to be expensive, which warrants investigation into more cost-effective alternatives. In addition, the pure silica matrix imparts a brittle nature to some ionogels, which may lead to loss of contact with the electrodes during battery cycling, and premature breakdown. Furthermore, lithium prices are currently rising very fast, due to an imbalance in supply and demand. This could eventually reverse the steady price drops which Li ion batteries have shown until now, and which are mandatory for the large scale breakthrough of electric vehicles on a large scale. In our group, we have investigated routes to tackle precisely these challenges. Research was done into deep eutectic solvents (DES) to replace ionic liquids both for LIBs and Na ion batteries (SIBs). The new class of hybrid solid electrolytes obtained with DES, are the so-called eutectogels (ETG) for LIBs. Na is much more abundant than Li and so, SIBs (sodium ion batteries) can be interesting alternatives to LIBs. It has been shown that SIB full cells with DES electrolyte have enormously enhanced the cycle life compared to cells containing conventional electrolyte. To enhance the mechanical properties of the material obtained with a pure silica matrix, two routes were developed. First of all, the silica matrix was replaced by a polymer matrix. This yielded a class of materials named polymer eutectogels (pETG). The first generation of the pETGs was found to be adequate for LIBs with LiFePO4 cathode, while a second generation was needed for NMC (Li(Ni,Mn,Co)O2) cathodes. Particularly in the last case, detailed studies of the interface between the electrolyte and electrode have shown a high stability. Alternatively, also the organic modification of the silica matrix has been investigated. Here, the focus lies on improving the mechanical properties and its effects on the battery operation stability, whilst maintaining the mostly inorganic nature of the matrix material. In conclusion, a summary of the group?s research progress regarding ionogels and eutectogels will be presented, outlining both the advantages and challenges of these interesting new materials. Partly published in: - Deep Eutectic Solvents as Nonflammable Electrolytes for Durable Sodium-Ion Batteries, D. De Sloovere et al., Adv. Energy and Sustainability Res., 2022, - Polymeric Backbone Eutectogels as a New Generation of Hybrid Solid-State Electrolytes, B. Joos et al., Chem. Mater., 32 (9) 2020 3783-3793 - Eutectogels: A New Class of Solid Composite Electrolytes for Li/Li-Ion Batteries, B. Joos et al. Chem. Mater. 30 (3) 2018 655-662

12:00 Discussion    
12:15 LUNCH    
Redox Flow Batteries : Cristina Flox
Authors : Ana Belen Jorge Sobrido*, Rhodri Jervis, Michael W Thielke, Maria Crespo Ribadeneyra
Affiliations : Associate Professor in Sustainable Energy Materials, UKRI Future Leaders Fellow School of Engineering and Materials Science, Queen Mary University of London *

Resume : The continuous emissions of greenhouse gases is one of the major environmental issues the world faces today. Wind power and solar energy are promising alternatives to fossil fuels in our aim to decarbonise global energy generation. However, with the increase in renewable generation comes a pressing need for effective energy storage. With the drastic fall in lithium ion battery cost in recent years, they have found a market in stationary storage applications, even though they are not particularly well suited to medium-to-large-scale grid storage (10 s of MWh), due to lifetime and cost issues. The technology with perhaps the greatest potential for safe and effective medium-long term storage is the Redox Flow Battery (RFB). RFBs offer long lifespan, high reliability and independent tuneable power and energy. A typical RFB consists of two electrolyte tanks from which the electrolytes with the electroactive species dissolved are circulated by pumping through two carbon electrodes. The role of the electrode is to provide active sites for the redox reactions and facilitate mass transport and charge transfer. Because of this, the performance of the RFB is highly dependent on the porous microstructure of the electrodes. Commercial electrodes usually consist of fibre carbon mats in the form of felts or papers. Although their use is widespread, these materials suffer from poor wettability and high-pressure drop. Here we present our work on alternative carbon electrode materials derived from lignin that has been processed in the form of freestanding fibre mats using electrospinning, a versatile technique that enables the fine control of the properties of the obtained materials including the tuning of the surface chemistry, conductivity, porosity and thickness, key parameters when designing electrodes.

Authors : M. Moghaddam1 and P. Peljo1
Affiliations : 1. Research group of Battery Materials and Technologies, Faculty of Technology, University of Turku, 20500 Finland /

Resume : Solid boosters are an emerging concept for improving the performance and especially the energy storage density of the redox flow batteries but information about electron transfer (ET) reactions between the redox active solid and the redox electrolyte in the tank are missing, scarce or scattered in the literature. So far, we have formulated how these systems work from the point of view of thermodynamics. We described possible pathways for charge transfer, estimated the overpotentials required for these reactions in realistic conditions, and illustrated the range of energy storage densities achievable considering different redox electrolyte concentrations, solid volume fractions and solid charge storage densities[1]. As the next step, we study the ET reactions in solid boosted flow batteries employing scanning electrochemical microscopy (SECM). SECM, with a micrometer scale spatial and millisecond scale temporal resolution, is able to track the local ET between the redox electrolyte and the redox solid. In the SECM set-up, active solid material is drop-casted on a glass that is immersed in the redox electrolyte similar to our system for studying oxygen absorption in electrocatalyst layers [2]. When the biased tip approaches the substrate, the reduced electrolyte species generated at the tip are oxidized by the substrate and recirculate to the tip, leading to a positive feedback. The biased tip being located in different distances from the substrate will oxidize and reduce the active solid material and the obtained current-time behavior provides information about kinetics of ET reactions. Employing SECM in solid boosted flow batteries provides valuable information on the kinetics of these systems and this knowledge improves the system’s operation. References [1] M. Moghaddam, S. Sepp, C. Wiberg, A. Bertei, A. Rucci, P. Peljo, Molecules 2021, 26, 1–19. [2] M. Moghaddam, P. Peljo, ChemElectroChem 2021, DOI 10.1002/celc.202100702.

Authors : M. Chakraborty1,2, T. Andreu1,3, M. Guc1, J.R. Morante1,3, S. Murcia-López1
Affiliations : 1 Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, Sant Adrià de Besós, 08930, Spain 2 Universitat Autonoma de Barcelona (UAB), Plaça Cívica, Bellaterra, 08193, Spain 3 University of Barcelona (UB), Martí i Franquès 1, Barcelona, 08020, Spain e-mail address:

Resume : Redox flow batteries (RFBs) are considered as one of the most promising large-scale energy storage technologies, significantly for the integration with renewable energies. However, so far, none of the RFB systems has significantly deployed to the marketplace due to several limitations such as low energy density, poor electrochemical performance, high cost. Among the various alternative RFB chemistries, zinc-iodide aqueous RFB (ZIFB) hold great promise for next-generation FBs applications due to their appealing features of cost-effectiveness, high safety, and high energy density. However, the performance of ZIFB is hindered by multiple critical challenges such as poor cyclability, capacity fading as a result of irreversible zinc plating and stripping, slow kinetics of the redox reactions. The electrolyte has a major contribution in scaling up the battery performance. In this work, we proposed an improved electrolyte design by introducing a low cost salt, NaCl, as an additive to enhance the electrochemical performance and cyclability of ZIFB. The half-cell electrochemical performance shows improved reversibility and kinetics of redox reactions which, further reflects in the promising cell cycling performances of high discharge capacity and excellent capacity retention. Such improvements are mainly attributed to the multifunctional roles of this cost-effective salt in the both sides redox reactions starting from the efficient Zn dissolution by the formation of soluble ZnClx complex on the surface of the anode, and freeing up the I- ions by I2Cl- formation. This encouraging results indicate that addition of a cost-effective salt, NaCl, enlighten a great prospect for high performance yet cost-competitive ZIFB applications. The work was funded by MICINN under CERES (PID2020-116093RB-C42) project. M. Chakraborty received PhD grant from the EU Horizon 2020 research and innovation programme (DOC FAM COFUND 2016) under the Marie Skłodowska-Curie grant agreement No 754397. Keywords: Aqueous Zn-iodide flow batteries, Supporting electrolyte, Redox reversibility, Zn deposition/dissolution, Cycle life.

Authors : Loïs BRIOT(a), Quentin CACCIUTTOLO(a), Martin PETIT(a), Marie-Cécile PERA(b)
Affiliations : (a) IFP Energies Nouvelles, Rond-Point de l’échangeur de Solaize, F-69360 Solaize, France. (b) FEMTO-ST Institute, FCLAB, Univ. Bourgogne Franche-Comté, CNRS, F-90000 Belfort, France.

Resume : Redox flow batteries are among preferential systems for stationary energy storage, which is taking more and more importance with the growing share of renewable energy generation. Since 2013, research around redox flow batteries tends to diversify towards organic systems. Active molecules utilized in such aqueous organic batteries (quinones, viologens, TEMPO etc.) show potential advantages over vanadium, namely ability to be operated in neutral or basic media, low cost and no criticity, while being harmless for human and the environment. However, stability and durability issues because of chemical or electrochemical degradations still hinder their massive development. Our work focuses on understanding and modelling aqueous organic flow batteries aging mechanisms, and how they affect battery’s performances (energy fade, coulombic or energy efficiency loss). In such batteries, electrolytes degradations are usually a main concern compared to membrane issues or electrodes corrosion. Degradations are studied via a combined modelling/experimental approach, using a well described in the literature 2,6-DHAQ/Fe(CN)6 cell system as reference [1,2]. 0D multiphysics model has been developed because this modelling scale enables long-time scale simulations, while still being able to describe the physical reality of a redox flow cell. The base model considers electrochemical main reactions as well as water splitting reactions, mass transport through membrane and electrodes, liquid electrolyte transport and pressure losses, and an electric part in electrodes, electrolyte, and membrane [3]. Chemical degradations, electrochemical degradations towards inactive species, and electrochemical degradations forming new redox couples, corresponding to frequently encountered degradations, were added to the model. Calibration and validation of the model is done with the help of dedicated cycling aging experiments at different current densities, temperatures, and voltage limits, both in symmetric cells (to suppress crossover) and in full cells. Post-aging samples are characterized by cyclic voltammetry, 1H and 13C NMR and HPLC-MS, to help identify and quantify degradations. This model is used to gain insights into how aging impacts long term behaviour of flow batteries using organic electroactive species. Understanding degradations mechanisms and how operating parameters influence them is essential for improving operating conditions, thus increasing global lifetime of the system. Furthermore, since degradations described in the model are frequently encountered in aqueous organic flow batteries, this work can be easily extended to similar electroactive organic species. References [1] M.-A. Goulet, L. Tong, D.A. Pollack, D.P. Tabor, S.A. Odom, A. Aspuru-Guzik, E.E. Kwan, R.G. Gordon, M.J. Aziz, Journal of the American Chemical Society (2019). [2] K. Lin, Q. Chen, M.R. Gerhardt, L. Tong, S.B. Kim, L. Eisenach, A.W. Valle, D. Hardee, R.G. Gordon, M.J. Aziz, M.P. Marshak, Science 349 (2015) 1529–1532. [3] Q. Cacciuttolo, M. Petit, D. Pasquier, Electrochim. Acta (2021) 138961.

16:15 Discussion    
Authors : Yongdan Li a,b,c*
Affiliations : a) Department of Chemical and Metallurgical Engineering, Aalto University, Kemistintie 1, FI-00076 Aalto, Finland b) State Key Laboratory of Chemical Engineering (Tianjin University), Tianjin Key Laboratory of Applied Catalysis Science and Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China c) Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China E-mail of corresponding author:

Resume : Redox flow battery (RFB) stands out as a promising energy storage technology owing to its independent power and energy features, long cycle life, and rapid response. Compared with the aqueous RFBs, the non-aqueous RFBs (NARFBs) have received increasing attention because of their wider electrochemical window and thus higher energy density. However, the performance of NARFBs has insufficient for commercialization, the lack of high ionic selectivity and ionic conductivity membrane is the key limiting factor. To improve the performance and efficiency, many novel membranes have been developed subsequently. In my group, we synthesized a two-dimensional (2D) metal organic framework (MOF) modified Celgard membrane via an infiltration method and achieved 82% EE at a current density of 12 mA cm-2. We also synthesized 2D vermiculite nanosheets modified porous membrane and achieved 85.8% EE at 2 mA cm-2. Furthermore, we proposed to utilize an intrinsic composite membrane to enhance the performance of the battery. For instance, we developing a novel highly selective MOF-based mixed-matrix membrane and a porous poly(vinylidene fluoride) membrane with 2D vermiculite nanosheets. Keywords: Non-aqueous redox flow battery, Membrane, Metal organic framework, Two dimensional materials

Authors : Puiki Leung
Affiliations : School of Energy and Power Engineering, Chongqing University, ChongQing, China

Resume : To ensure deeper market penetration, electrolytes of redox flow batteries (RFB) should be based on low-cost and abundant materials. All-organic systems based on new types of organic molecules are developed, from a study of theoretical calculations, fundamental chemistry to full-cell testing. The selection of organic active materials in relation to their physical and chemical properties (reaction kinetics, electrode potentials and solubilities) were facilitated by density functional theory (DFT) calculations. Based upon the results, we proposes new multi-electron active molecules with new reaction mechanisms that are capable of delivering multi-electron transfers and exhibiting superior electrode potentials in both aqueous and non-aqueous electrolytes. The proposed molecules were successfully demonstrated with reasonable solubilities (> 1 M) while demonstrating reversible behaviours using conventional electrochemical techniques. Following these, stable charge-discharge cycling performances of these active molecules were also performed with relatively high energy efficiencies (> 60 %) over prolonged operations, demonstrating the prospects of alternative organic molecules for future redox flow battery applications. Keywords: flow battery; organic; reaction mechanism

Authors : Romadina E.I.[1], Stevenson K.J.[1]
Affiliations : [1] Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, bld. 1, Moscow, Russia

Resume : The rapid growth of the role of renewable energy sources dictates new requirements for electrochemical energy storage devices [1]. Among them, redox flow batteries (RFBs) are regarded as a promising technology, since their advantages of excellent scalability, low cost, easy fabrication and operation, long lifetime, and safety. Today inorganic RFBs are penetrating the market, however, low specific capacity in conjunction with low electrochemical stability window of aqueous electrolytes (≈1.5 V) and safety issues, hinders their wide-scale commercialization. [2]. Herein, we studied a group of organic materials based on aromatic amines with general formulas of NPh3RnBrm and N2Ph5RnBrm where R=-(OCH2CH2)2-OCH3. All the compounds demonstrated high solubility in MeCN, which potentially enables outstanding specific capacities approaching 134 Ah L-1 [3]. Compounds demonstrated one or two quasi-reversible electron transition processes with redox potential up to 0.6 V vs. Ag/AgNO3 reference electrode, which makes them perspective catholyte materials. For the RFB investigation butylviologen perchlorate ( 0.75V vs. Ag/AgNO3, ~1.15 V battery voltage) was chosen as the redox pair. Firstly, the selection of the most appropriate electrolyte was performed: it was shown that the usage of the TBABF4 and NaClO4 produces stable characteristics of RFB performance. Final RFB tests proved that the most promising systems are capable to exhibit 65% of maximum capacities and more than 95% Coulombic efficiency after 50 cycles [3]. In the next step, we synthesized and investigated novel phenazine derivative with oligomeric ethylene glycol ether substituents as promising anolyte material [4]. The designed compound undergoes a reversible and stable reduction at -1.72 V vs. Ag/AgNO3 and demonstrates excellent (>2.5 M) solubility in MeCN. A non-aqueous organic redox flow battery assembled using novel phenazine derivative as an anolyte and substituted triarylamine derivative as a catholyte exhibited high specific capacity (~93% from the theoretical value on the first cycles), >95% Coulombic efficiency and good cycling stability. To summarize, investigated materials establish themselves attractive for future research: obtained parameters open promising future directions for their usage as redox-active materials for non-aqueous RFBs. Romadina Elena acknowledges the support provided by Haldor Topsøe A/S Scholarship 2021. [1] Panwar N., Kaushik, S., Kothari S. Renew. Sustain. Energy Rev. 2011, 15 (3), 1513 1524. [2] Placke T., Heckmann A., Schmuch, R., Meister P., Beltrop K., Winter, M. Joule 2018, 2 (12), 2528 2550. [3] (a) Romadina E., Volodin I., Stevenson K., Troshin P. JMC-A, 2021, 9, 8303-8307; (b) Romadina E., Troshin P., Stevenson K., Patent RU2752762C1 “Highly soluble triphenylamine-based catholyte and electrochemical current source based on it” [4] Romadina E., Komarov D., Stevenson K., Troshin P. ChemComm, 2021, 57, (24), 2986-2989

17:45 Discussion    
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Lithium ion batteries : Cristina Flox
Authors : Alejandro A. Franco
Affiliations : Laboratoire de Réactivité et Chimie des Solides (LRCS), CNRS UMR 7314, Université de Picardie Jules Verne, Hub de l’Energie, 15 Rue Baudelocque, 80039 Amiens, France;Réseau sur le Stockage Electrochimique de l'Energie (RS2E), Fédération de Recherche CNRS 3459, Hub de l’Energie, 15 Rue Baudelocque, 80039 Amiens, France; ALISTORE-European Research Institute, Fédération de Recherche CNRS 3104, Hub de l’Energie, 15 Rue Baudelocque, 80039 Amiens, France; Institut Universitaire de France, 103 Boulevard Saint-Michel, 75005 Paris, France

Resume : In this lecture I discuss the latest progresses achieved with the computational modeling platform developed in the ARTISTIC project[1] which is able to predict the impact of manufacturing parameters on electrode and lithium ion battery (LIB) cell properties. This platform is supported on a hybrid approach encompassing a physics-based multiscale modeling workflow, machine learning models and high throughput experimental characterizations.[2] Different steps along the battery cells manufacturing process are simulated, such as the electrode slurry preparation, the coating, the drying, the calendering and the electrolyte infiltration. The multiscale physical modeling workflow couples experimentally-validated Coarse Grained Molecular Dynamics, Discrete Element Method and Lattice Boltzmann Method simulations and it allows predicting the impact of the process parameters on the final electrode mesostructure in three dimensions. The predicted electrode mesostructures are injected in a 3D-resolved continuum performance simulator capturing the influence of the pore networks and spatial location of carbon-binder within the electrodes on the solid electrolyte interphase formation (for anodes) and on the electrochemical response (of anodes vs. lithium, cathodes vs. lithium and the full cells). Machine learning models are used to accelerate the physical models’ parameterization, to mimic their working principles and to unravel manufacturing parameters interdependencies from the physical models’ predictions and experimental data, and as a guideline for reverse engineering. The predictive and optimization capabilities of this platform, coupling physical models with machine learning models, are illustrated with results for different electrode formulations and active material chemistries. Finally, I present the ARTISTIC Online Calculator, a free online service using our physics-based models, which allows you to predict the influence of manufacturing parameters on electrode architectures using your internet browser. References: [1] The ERC-funded ARTISTIC project website: ; [2] List of the ARTISTIC project publications:

Authors : Cressa, L.* (1), Sun, Y. (2), Kopljar, D. (2), Burkhardt, C. (3), De Castro, O. (1), Gerard, M. (1), Wirtz, T. (1), Eswara, S. (1)
Affiliations : (1) Advanced Instrumentation for Nano-Analytics (AINA), MRT Department, Luxembourg Institute of Science and Technology, 41, rue du Brill, L-4422 Belvaux, Luxembourg; (2) German Aerospace Center (DLR), Institute of Engineering Thermodynamics, Pfaffenwaldring 38-40, 70569 Stuttgart, Germany; (3) Natural and Medical Sciences Institute (NMI) at the University of Tübingen, Markwiesenstr. 55, 72770 Reutlingen, Germany

Resume : One of the major challenges towards a sustainable and greener society, is to develop efficient and secure energy storage systems. Lithium-ion batteries, being among the most prominent candidates, unfortunately still present some drawbacks. Thus far, commercial batteries still suffer from safety issues, capacity loss and cyclic degradation [1]. Consequently, the research interest is tremendous, and a plethora of new materials and composites are emerging daily. To investigate the performance degradation mechanisms, a multimodal characterization is often needed. Thus, we developed an analysis approach which allows to correlate high-resolution chemical and structural information of battery materials. The structural analysis is performed via Scanning Electron Microscope (SEM) imaging in a dual-beam Focused Ion Beam (FIB)-SEM instrument, and the chemical characterization is done with the FIB in combination with an in-house developed high-resolution high-sensitivity Secondary Ion Mass Spectrometer (SIMS) which is attached to the same FIB-SEM instrument. Both techniques can reach nm-range resolutions. Especially the implementation of a SIMS system is attractive as it is capable of detecting light elements such as H, Li, Be and B [2]. The latter are, on one hand, particularly difficult to characterize using conventional analytical techniques such as Energy Dispersive X-ray Spectroscopy and on the other hand, essential when investigating lithium-ion batteries. We are currently using the FIB-SEM-SIMS analysis methodology to study all solid-state Li batteries using LLZO garnets as solid electrolyte. The analytical method is used to inspect the characteristics of the components in the initial state (e.g. the quality of the adhesion between lithium metal anode and the LLZO) as well as in the cycled state. Furthermore, we designed an in operando FIB-SEM-SIMS sample holder, which allows charging and discharging solid state batteries or half cells. This enables the possibility to follow the structural and chemical evolution over several charge-discharge cycles and to identify the precise degradation mechanisms. The entire workflow is performed under high vacuum within the same instrument without the need to transfer the sample and risk contamination. In this presentation, we will showcase our latest experimental results to demonstrate the FIB- SEM-SIMS analytical methodology for battery materials. Ultimately, with this work we aim to reveal the complex relation between morphological appearance, chemical composition and electrochemical performance. We believe that correlative analysis approaches can give scientists valuable insights to understand and improve novel battery materials [3]. Acknowledgement: Financial support by the Luxembourg National Research Fund (FNR) through the INTERBATT project (INTER/MERA/20/13992061) is gratefully acknowledged. References [1] T. Waldmann et al., J. Electrochem. Soc. 163 (2016) A2149-A2164. [2] T. Wirtz et al., Nanotechnology 26 (2015) 434001. [3] M. Sun et al., ACS Energy Lett. 6 (2021) 451–458.

Authors : Sahar Lausch, Andreas Krause-Bader, Robert Gorgas, Toni Buttler, Susan Fülle, Marcel Neubert
Affiliations : Sahar Lausch; Andreas Krause-Bader; Robert Gorgas; Susan Fülle; Marcel Neubert are with the NORCSi GmbH Battery Company, Weinbergweg 23, D-06120 Halle, Germany. Toni Buttler is with the Interdisciplinary Centre for Materials Sciences (IZM), Martin Luther University Halle-Wittenberg, D-06120 Halle, Germany.

Resume : Silicon is one of the most promising anode materials replacing metallic Li due to a maximum specific capacity of 3579 mAh/g at room temperature to fabricate high-capacity anodes for lithium-ion batteries (LIB). However, the insertion of lithium in silicon is accompanied by a volume expansion of more than 300%, which hinders the use of layered Si structures due to pulverization of the electrode. The introduction of nanoscale structures such as nanowires and nanodots have been intensively investigated to reduce stress and overcome the intense volume expansion [1-2]. In layer structures, the patterning of Si anodes by photolithography and etching techniques [3] are proposed to enable the usage of Si layers in LIB. In 2012, He et al. reported the formation of Kirkendall voids in a Si-Cu layer structure, which effectively helps to compensate stress of the Si layer and resulting in an excellent cycling performance [4]. The Kirkendall effect is caused by the difference in diffusion rate of two different materials. In a non-equilibrium state of diffusion at the interface, the vacancies condense and form voids on the side of the atom with the faster diffusion rate [5]. In our work, we take advantage of the Kirkendall voids and create a thick multilayer of alternating Cu and Si layers. A patented temperature step with ultra-fast annealing helps to control the formation of Kirkendall voids shown in cross-sectional SEM. Furthermore, with low-energy tempering, the voids are formed, while for high- energy tempering, the formation of voids are suppressed and a full silicidation takes place. The void size can be controlled with the amount of copper or other metals in the layer. As prepared Si-Cu electrodes up to 5 µm thickness have been used to fabricate LIB coin cells with LiCoO2 cathode and LP30 electrolyte. No additive for SEI control is needed. The cells are cycled with a rate of C/2 in voltage rage between 3.0-4.0 V. Results show that the increase of Cu thickness and subsequent larger voids support the improved cycling performance with a specific Si capacity above 2000 mAh/g. Coulomb efficiencies above 99.5 % are achieved even after 50 cycles for a samples deposited by different thicknesses of Cu layer. References [1] Chan, Candace K., et al. NAT NANOTECHNOL 3.1 (2008): 31-35. [2] Krause, A., et al. J ELECTROCHEM SOC 166.3 (2019): A5378. [3] McSweeney, W., et al. NANO RES 8.5 (2015): 1395-1442. [4] He et al., J ELECTROCHEM SOC, 159 (12) A2076-A2081 (2012) [5] Kim et al., J MATER SCI: MATER ELECTRON, 22:703–716 (2011)

Authors : Lelotte, B.* (1), Vaz, C. A. F. (2), Pelé, V. (3), Jordy, C. (3), Gubler, L. (1) & El Kazzi, M. (1)
Affiliations : (1) Electrochemistry Laboratory, Paul Scherrer Institut, Villigen PSI, Switzerland (2) Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland (3) SAFT, Direction de la Recherche, Bordeaux, France

Resume : All-solid-state batteries (ASSBs) are closer than ever to wide-scale applications. They could bring improved safety, an enlarged temperature stability and extended cycle life compare to conventional Li-ion batteries using liquid electrolytes. If the compact solid electrolyte (SE) can stabilize Li metal dendrites growth, ASSBs would also level up two to three times the energy density. For the past decades, research has focused on improving the ionic conductivity of the SEs, until the discovery of the thiophosphate family, with an ionic conductivity similar or exceeding those of liquid electrolytes. However, due to their narrow electrochemical stability window, currently, the stronger focus is on the stabilization of their interfaces with both cathode and anode materials to improve the ionic transport. Understanding the degradation reaction mechanism taking place at these buried interfaces is extremely challenging. It requires the use of non-destructive surface sensitive techniques capable to provide depth profile chemical analysis combined with an excellent lateral resolution to discriminate signals originating from the surface and near surface of the different particles (active materials, solid electrolyte and conductive carbon additive) composing the working electrode. In this contribution, we present detailed surface and interface (electro-)chemical study of the working electrode (NCM622/LPSCl/C) cycled up to 4.3 V vs. Li+/Li. First, galvanostatic cycling and impedance spectroscopy demonstrate, as expected, a large irreversible charge of 32% during the 1st cycle and the gradual increase of the impedance with the number of cycles. Second, the interface chemical evolution is monitored by soft-X-ray absorption spectroscopy (XAS) at the TMs, P and S L-edges, as well as, at the C and O K-edges providing very crucial knowledge on the oxidation states and structural evolution during cycling of both NCM622 and LPSCl. The XAS acquisition is performed by combining measurements with the (i) high lateral resolution and surface sensitivity of X-ray photoemission electron microscopy (XPEEM) and (ii) depth profile total electron yield (TEY) and total fluorescence yield (TFY) at the SIM beamline of the synchrotron Swiss Light Source. Our results demonstrate that the 1st irreversible charge is mainly associated with LPSCl oxidation but the gradual impedance increase is caused also by the surface degradation on the NCM622 leading to the formation of inactive reduced TMs species. The full picture of the interface reaction will be presented by emphasizing the role of the unstable layered oxygen and the possible diffusion of TMs leading to the formation of sulfate, sulfide, phosphate and phosphide species.

Authors : Gwenaëlle COURBARON (1,2), Nathalie DELPUECH (1,3,4), Emmanuel PETIT (2,3,4), Jon SERRANO (2,4,5), Dany CARLIER (2,3,4), Jacob OLCHOWKA (2,3,4), Christine LABRUGERE (6), Cyril AYMONIER (2,3), Laurence CROGUENNEC (2,3,4)
Affiliations : (1) Renault SAS, Technocentre, 1 avenue du golf, 78280 Guyancourt, France (2) Univ. Bordeaux, CNRS, Bordeaux INP, ICMCB UMR 5026, F-33600 Pessac, France (3) RS2E, Réseau Français sur le Stockage Electrochimique de l’Energie, FR CNRS 3459, France (4) ALISTORE-ERI European Research Institute, FR CNRS 3104, 80039 Amiens Cedex France (5) CIC Energigune, Albert Einstein 48, Parque Tecnologico de Alava, Miñano 01510, Spain (6) PLACAMAT, UMS 3626, CNRS Université Bordeaux, 33600 Pessac, France

Resume : Disruptive technology is necessary to improve battery energy and power densities with a significantly increased safety. Among positive electrode materials being attractive candidates for next battery generations, both Lithium ion batteries and all solid-state batteries, spinel LiNi0.5Mn1.5O4 (LNMO) appears as one of the favourite thanks to its numerous advantages: Co-free and thus more sustainable and with lower cost, high voltage (4.7 V vs Li+/Li) and thus high energy density (650 Wh/kg). Nevertheless, challenges are remaining before its integration in next generations of batteries, due to its reactivity at high voltage at the interface between the electrode and the (liquid or solid) electrolyte. Formation of protective surface layers is one of the route prospected to stabilize this interface. In this work, commonly used wet coating process will be compared to supercritical fluid chemical deposition (SFCD) in order to evaluate the advantage of this latter, that was previously shown to allow with success the formation of homogeneous and continuous coating at the surface of BaTiO3 particles 1. The main advantage of this process is its ability, as atomic layer deposition (ALD), to control precisely the thickness of the coating, but on powders and not only on electrodes as for ALD. Al2O3-type coating was chosen as abundant, cheap and simple to prepare by different synthesis processes. We will show that coated LNMO materials were prepared with optimal thickness for the Al-rich coating and that very attractive electrochemical performances were obtained, especially at high rates2. These composite materials have been characterized in-depth combining X-ray diffraction, scanning and transmission electron microscopy, as well as Infra-red, Raman, X-ray photoelectron and nuclear magnetic resonance spectroscopies. [1] Aymonier, C. et al. Supercritical Fluid Technology of Nanoparticle Coating for New Ceramic Materials. J. Nanosci. Nanotechnol. 5, 980–983 (2005). [2] Courbaron G., Delpuech N., Croguennec L., Aymonier C., & Petit E. (2021). Matériau d’électrode enrobé d’un composé particulier (FR2114404)

10:30 Discussion    
10:45 Break    
Authors : Abdolkhaled Mohammadi Laure Monconduit Lorenzo Stievano Reza Younesi
Affiliations : 1 ICGM, University Montpellier, CNRS, Montpellier, France 2 Department of Chemistry – Ångström Laboratory, Uppsala University, Box 538, 75121 Uppsala, Sweden 3 Alistore-ERI, CNRS FR, Amiens 3104, France 4 RS2E, CNRS, Amiens, France

Resume : Over the past four decades, many researchers have studied rechargeable Li metal batteries (LMB) as a promising system due to the low electrochemical potential and high theoretical specific capacity of the lithium metal negative electrode [1]. Despite extensive research on LMB, their commercialization continues to be hampered by their poor performance, and the origin of many essential factors governing it remains elusive [2]. One of these parameters is the nucleation overpotential, which represents the energy required to form the Li nuclei during plating. Although some research has been carried out on the nucleation overpotential of Li metal [3-5], still little is known on its origin. In the literature, this phenomenon is often measured with a two-electrode setup, which fails to demonstrate the contribution of the working and counter electrodes independently. To achieve a clear view of nucleation overpotential, we used a three-electrode setup to deconvolute the potential associated with each electrode during galvanostatic Li electrodeposition. Our findings demonstrate that the main source of observed polarization is a quick drop in the potential of the counter electrode (lithium foil), which can be attributed to Li stripping from the counter-electrode. This finding may aid in clarifying the origins of the experimental polarization, preventing researchers from misinterpreting it in terms of nucleation overpotential. References: [1] Cheng, Xin-Bing, et al. "Toward safe lithium metal anode in rechargeable batteries: a review." Chemical reviews 117.15 (2017): 10403-10473. [2] Horstmann, Birger, et al. "Strategies towards enabling lithium metal in batteries: interphases and electrodes." Energy & Environmental Science 14.10 (2021): 5289-5314. [3] Yan, Kai, et al. "Selective deposition and stable encapsulation of lithium through heterogeneous seeded growth." Nature Energy 1.3 (2016): 1-8. [4] Pei, Allen, et al. "Nanoscale nucleation and growth of electrodeposited lithium metal." Nano letters 17.2 (2017): 1132-1139. [5] Biswal, Prayag, et al. "Nucleation and early-stage growth of Li electrodeposits." Nano letters 19.11 (2019): 8191-8200.

Authors : María Bernechea1,2,3,4*, Sergio Aina1,2, M. Pilar Lobera1,2,3
Affiliations : 1 Instituto de Nanociencia y Materiales de Aragón (INMA) CSIC-Universidad de Zaragoza, Zaragoza, Spain 2 Departamento de Ingeniería Química y Tecnologías del Medio Ambiente, Universidad de Zaragoza, Zaragoza, Spain 3 Networking Biomedical Research Centre of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain 4 ARAID, Zaragoza, Spain *

Resume : Energy storage systems will play an essential role in reducing fossil fuel consumption and greenhouse gas emissions by providing solutions to store energy produced from renewable sources and implement electrical mobility. Graphite is the conventional material used to fabricate standard rechargeable batteries and supercapacitors. Nonetheless, it has some limitations such as limited intrinsic capacity, lithium-ion insertion capacity, and specific capacitance. Additionally, graphite, together with lithium and cobalt, characteristic materials used in Li-ion batteries, are limited resources, especially since Europe depends on importation and external supply. In this sense, UNIZAR is leading the European project NOEL: Innovative Nanostructured Electrodes for Energy Storage Concepts preparing new functionalized carbons with non-toxic nanocrystals to be used as electrode materials for post-lithium batteries and supercapacitors, in collaboration with the National Institute of Chemistry (NIC) in Slovenia and the Poznan University of Technology (PUT), Poland. The presence of metal sulphide nanocrystals on the carbon surface can bring interesting features like higher surface/volume ratio, which can increase the contact area between electrode and electrolyte, more ion adsorption sites, smaller distances for ion or electron transport and better accommodation of the mechanical strain and structural distortion. Novel carbon-nanoparticle hybrids have been prepared, using new carbons synthetized at NIC as well as commercial carbons, for their use as electrodes in batteries and supercapacitors. The characterisation techniques confirm the incorporation of nanocrystals, the control on the preparation and its reproducibility.

Authors : Madec, L.*(1,2), Ledeuil, J.B.(1), Tang, C.(2,3), Giaume, D.(2,4), Guerlou-Demourgues, L.(2,3), Monconduit, L.(2,5), Martinez, H.(1,2)
Affiliations : (1) Universite de Pau et des Pays de l’Adour, E2S UPPA, CNRS, IPREM, Pau, France; (2) Réseau sur le Stockage Electrochimique de l’Energie, CNRS FR3459, Amiens, France; (3) Bordeaux, Bordeaux INP, ICMCB UMR5026, F-33600 Pessac, France; (4) Chimie-ParisTech, PSL Research University, CNRS, IRCP, 75005 Paris, France; (5) ICGM, Université de Montpellier, CNRS, Montpellier, France

Resume : In the field of energy storage, bulk chemical/morphological information of composite materials and electrodes and their evolution during cycling are of high interest. However, conventional analytical methods are often limited to access to the bulk properties of composites as they are buried. To tackle this challenge, samples preparation by cross-section coupled to nano-Auger analysis is developed as a suitable alternative. In the case of conversion-based electrodes for Li-ion batteries and beyond, direct evidence of the conversion reaction after long term cycling remains to be elucidated so far. Here, cross-section Auger imaging allows revealing the chemical/morphological evolution of TiSnSb conversion material at the electrode scale with a nano resolution.[1][2] Importantly, results show that the conversion mechanism still occurs even after 400 cycles, which was unexpected. In the case of pseudocapacitive composite materials for hybrid supercapacitors, their bulk organization and structure remain a challenge to investigate. Here, cross-section Auger imaging allows revealing the nanoscale assembly and porosity of Mn-Co composites prepared by exfoliation/restacking, which could not be proven so far.[3] Overall, a good correlation between the restacking method, the nanoscale organization/structure of composites and resulting electrochemical performance was obtained. Finally, the innovative cross-section Auger approach presented here is suitable to get reliable and relevant bulk chemical/morphological information in composites for energy storage and will also benefit to other research fields. References [1] L. Madec, J.-B. Ledeuil, G. Coquil, L. Monconduit, H. Martinez, Cross-Section Auger / XPS imaging of conversion type electrodes: how their morphological evolution controls the performance in Li-ion batteries, ACS Appl. Energy Mater. 2 (2019) 5300. [2] L. Madec, J.B. Ledeuil, G. Coquil, G. Gachot, L. Monconduit, H. Martinez, Cross-section Auger imaging: A suitable tool to study aging mechanism of conversion type electrodes, J. Power Sources. 441 (2019) 227213. [3] L. Madec, C. Tang, J. Ledeuil, D. Giaume, L. Guerlou-demourgues, H. Martinez, Cross-Section Auger Analysis to Study the Bulk Organization / Structure of Mn-Co Nano-Composites for Hybrid Supercapacitors, J. Electrochem. Soc. 168 (2021) 10508.

12:00 Discussion    
12:15 Lunch    
Authors : T. Tite*(1), H. Ghannam(1,2), O.Elkhouja(1,3), C. Ungureanu(4), M. Buga(4), A. A. Zaulet(4), I. Stavarache(1), E. Matei(1), M. Y. Zaki(1), C. C. Negrila(1), A.C. Galca(1), G.E. Stan(1), A. Galatanu(1), M-C. Bartha(1), M. Baibarac(1), A. Chahboun(2)
Affiliations : (1) National Institute of Materials Physics, RO-077125 Magurele, Romania (2) Abdelmalek Essaadi University, FSTT, Thin Films and Nanomaterials Lab., 90000 Tangier, Morocco (3) Laboratory of Materials and Subatomic Physics, Faculty of Sciences, Ibn Tofail University, Campus Universitaire, 14000 Kenitra, Morocco (4) National Research and Development Institute for Cryogenics and Isotopic Technologies - ICSI Rm. Valcea, Uzinei Street no. 4, PO Box Râureni 7, 240050, Râmnicu Vâlcea, Romania

Resume : Advanced electrochemical energy storage devices (ESDs) are internationally considered as one of the disruptive technologies of the future. On the main trends that drive energy storage development in our daily life is the rise of electrical devices. Lithium-ion batteries (LIBs) have revolutionized our society, since its first commercialization in 1991 by Sony. Despite its great success, LIBs need to be improved in term of energy power density, speed charge capabilities, cost, and safety. Notably, such safety risks are unacceptable for autonomously powered medical implants, residing inside the human body. In this context, in recent years, extensive efforts have been devoted to design new anodes or cathodes, improve the electrolyte properties or designing new batteries more sustainable (e.g. Sodium-ion batteries (SIBs)) [1]. Among new materials investigated in the literature, transition metal oxides (TMO) (e.g. vanadium oxide (VOx) and zinc oxide (ZnO)) have shed new promises for future ESDs electrodes in regards to their unique physico-chemistry properties, such as layered structures, thermal stability and high theoretical capacity [2,3]. VOx exist in various compositions (e.g. V2O5, VO2, V2O3 and VO). As anode material, V2O5 and ZnO can reach, respectively, a theoretical capacity of 1472 and 978 mAh/g, which are far more than the actual anodes (e.g. graphite ~372 mAh/g). As cathode, V2O5, V2O3, and VO2(B) can attain a theoretical capacity of 294, 356 and 324 mAh/g [3] which is higher than known cathode materials such as LiCoO2 (140 mAhg-1). Recently, TMO oxides in thin-film, two (2D) or one-dimensional (1D) nanostructured architecture have attracted the attention in ESDs field since their development can provide high surface area, short pathways and high kinetics for lithium ion insertion/extraction [4]. In the present work, we aim to synthesize directly on graphene (G)-based current collector, VOx and ZnO thin films/nanostructures by physical vapor deposition (PVD) and electrochemical deposition (ED) methods. The synergy of the undoped or doped oxides with graphene have been studied. The physico-chemical properties of the thin films were multi-parametrically surveyed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDXS), X-ray diffraction measurements (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The electrochemical performance was measured by using cyclic voltammetry, impedance and galvanostatic charge-discharge methods. SEM analysis have shown the formation of VOx and ZnO structure with opened porosity. Compared with the bare electrode, (Mg-doped) ZnO/V2O3 electrodes on graphene exhibited enhanced electrochemical properties. [1] A. El Kharbachi et al. J. Alloys Compd. 817, 153261 (2020) ; [2] Zhang et al., Journal of Energy Chemistry 59, 343?363 (2021) [3] Khac Hoang Bui et al., Nanomaterials, 11, 2001 (2021) [4] Yao et al., Journal of Alloys and Compounds 521, 95? 100 (2012)

Authors : Innocenti, A. (1, 2)*, Chen, Z. (1, 2) & Passerini, S. (1, 2)
Affiliations : 1) Helmholtz Institute Ulm (HIU), Germany 2) Karlsruhe Institute for Technology (KIT), Germany

Resume : Lithium-ion batteries are regarded as one of the keystone technologies of the energy transition of our society. But the projections on the required amounts of critical resources such as lithium, copper, nickel, and cobalt are raising concerns about the capability of maintaining an economical and constant supply of raw materials for their production. [1, 2] Therefore, new chemistries are being studied to find alternatives to the lithium-ion paradigm. In the last 20 years, organic materials for batteries have found extensive fortune among researchers. An uncountable number of monomers and polymers that can undertake redox reactions with alkali metals cations or anions were synthesized and tested on a laboratory scale. [3] Nevertheless, a systematic study on the cost and performances of commercial-like batteries made with such materials and the comparison with commercial and highly promising inorganic lithium-ion chemistries is necessary to understand the practical viability of organic batteries, and which specific classes of organic materials can be competitive. Using BatPac 4.0, an analysis on several organic redox monomers for lithium-ion batteries, selected after an extensive literature review, has been performed. [4] The software allows the simulation of different configurations of battery packs, and in this study, three kinds of packs, i.e., for domestic energy storage, plug-in hybrid vehicles, and fully electric vehicles, have been modeled. The cost, the specific capacity, the voltage curve, and the density of each material was calculated, estimated, or measured, according to the availability of such data in patents and scientific articles. Combinations of organic cathodes with organic anodes or Li-metal anode have been compared with NCM811 and LFP vs. graphite and Li-metal configurations. Effects of the amount of carbon in the organic electrodes and of the raw material cost have been also taken into account. [1] Greim, P., Solomon, A. A., Breyer, C.. Assessment of lithium criticality in the global energy transition and addressing policy gaps in transportation. Nat. Commun. 11, 4570, 2020 [2] Vaalma, C., Buchholz, D., Weil, M., Passerini, S.. A cost and resource analysis of sodium-ion batteries. Nat. Rev. Mater. 3, 18013, 2018 [3] Esser, B., Dolhem, F., Becuwe, M., Poizot, P., Vlad, A., Brandell D.. A perspective on organic electrode materials and technologies for next generation batteries. J. Power Sources 482, 228814, 2021 [4] Nelson, P. A., Ahmed, S., Gallagher, K. G., and Dees, D. W.. Modeling the Performance and Cost of Lithium-Ion Batteries for Electric-Drive Vehicles, Third Edition. United States: N. p., 2019 A.I. acknowledges the EU’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement N. 860403 “POLYSTORAGE” for the funding of the position. All the authors thank the support of the Helmholtz Association for the basic funding.

Authors : Gianlorenzo Bussetti1, Claudia Filoni*1, Lamberto Duò1, Franco Ciccacci1, Klaus Wandelt2
Affiliations : 1) Department of Physics, Politecnico di Milano (Italy) 2) Institute of Physical and Theoretical Chemistry, Bonn University (Germany)

Resume : Copper has been termed the ?metal of the 21st century?. In particular, the electrochemical production of integrated copper circuitry (?Damascene Process?) has revolutionized information technology. The steadily decreasing dimensions of the wires and vias of the circuitry calls for a detailed understanding of the electrochemical behaviour of copper on the nanometer, even atomic, scale. This obviously turns the gaze on the influence of atomic scale surface defects in the underlying electrochemical deposition and etching processes. In this contribution we present in situ electrochemical scanning tunneling microscopy (EC-STM) results, i.e. registered in solution, on the reconstruction of well-defined vicinal Cu(111) electrodes of progressively reduced terrace width (e.g. Cu(21 21 16) and Cu(221)) in dilute sulfuric acid solution (H2SO4). In contact with H2SO4 the flat reference Cu(111) electrode is known to reconstruct due to a strong interaction between copper and the sulfate anions, thereby forming a very stable Moiré ? superstructure. A slight distortion of this superstructure leads to the formation of three 120° rotated domains. We observe a distribution of terrace widths of the Cu(221) electrode after anodic adsorption of SO4 ? anions. All the measured three widths (1.2nm (1); 2.1 nm (2) and 3,3 nm (3)) are significantly larger than the terrace width of the bare Cu(221) surface (0.74 nm), but fully consistent with multiples of the size of a Moiré unit in different orientation. The underlying adsorbate induced transport processes may be suited to control the surface topography of surfaces, e.g. before the deposition of further species, and confined systems.

Authors : Ali Zitouni, Gherici Remil, Bouabdellah Bouadjemi, Samira Cherid, Yamina Sefir, Mohamed Houari, Mohamed Matougui, Tayeb Lantri and Samir Bentata.
Affiliations : Laboratory of Technology and of Solids Properties / Faculty of Sciences and Technology, BP227 AbdelhamidIbn Badis University, 27000 Mostaganem, Algeria

Resume : First-principles calculations for the structural, electronic, magnetic, elastic and thermodynamic properties of full-Heusler compound Co2TiPb, have been performed for using full-potential linearized augmented plane wave (FP-LAPW) scheme within the GGA approximation. Features such as the lattice constant, bulk modulus, and its pressure derivative are reported, in addition to the results of the band structure and the density of states. In all studied compounds, the stable type Cu2MnAl was energetically more favourable than type Hg2CuTi structure. The electronic structure in the ferromagnetic configuration for Co2TiPb Heusler compound shows that the spin-up electrons are metallic, but the spin-down bands are semiconductor. From electronic calculations, it is found that all the compounds studied have an indirect band gap with a half-metallic behavior. The compound Co2TiPb has a total magnetic moment of 2, well consistent with the Slater-Pauling rule. The elastic constants reveal that the Co2TiPb are mechanically stable and the Poisson’s ratio confirmed that the alloys considered are ductile. Finally, we calculated the thermodynamic properties such as heat capacity, thermal expansion and Debye temperature using the quasi-harmonic Debye model at temperatures from 0 to 1200 K.

16:00 Discussion    
16:15 Break    
Authors : Vagenas M.* (1,2), Plakantonaki N. (1), Giannakopoulou T. (1), Todorova N. (1), Papailias I. (1), Argirusis C. (2), Trapalis C. (1) * lead presenter
Affiliations : (1)Institute of Nanoscience and Nanotechnology, National Centre for Scientific Research “Demokritos”, 15341, Greece (2) School of Chemical Engineering, National Technical University of Athens, 15773, Greece

Resume : Carbon electrode technology is rapidly accelerating throughout the last few decades and a lot of research effort has been focused on electrochemical devices and mechanisms. Redox active conducting polymers are considered promising organic materials for electrochemical devices due to their favorable properties such as conductivity, reversibility and environmental stability. They have the ability to store electric energy as pseudo-capacitors and have been explored extensively as materials in secondary energy storage devices because of their apparent advantages, such as structure and morphology control, low weigh, flexibility and relatively low cost. Polypyrrole (PPy) is one of the most promising conductive polymers for industrial application as it can be easily prepared by chemical oxidation of monomer in acidic aqueous environment. In particular, Iron (III) chloride (FeCl3) and ammonium persulfate (APS) are the most frequently used oxidants of the pyrrole. Typical granular PPy has some drawbacks regarding its specific surface area which is a major property for electrochemical electrodes. In this work we present a composite material of one-dimensional PPy nanotubes (PNTs) and porous carbon as a candidate for use in electrochemical applications such as capacitive deionization (CDI), which is a water desalination technology where electrical field is applied while the feed water flows between two electrodes. As a result, the ions in the saline feed are adsorbed on the opposite electrodes reducing the water salinity. During the process, no high pressure needs to be applied. The resultant composites were characterized by Fourier Transform Infrared (FTIR) spectroscopy and their morphology was studied by scanning electron microscopy (SEM). The electrochemical performance of the nanocomposite electrodes was evaluated in 1M sodium chloride (NaCl) aqueous solution using a three-electrode configuration. Cyclic Voltammetry (CV), Galvanostatic Charge-Discharge (GCD) and Electrochemical Impedance Spectroscopy (EIS) measurement techniques were used to determine the specific capacitance. The Carbon/PNTs composites obtained exhibited reversible electrochemical properties even in a neutral aqueous environment, probably due to the π-π interaction between the materials. Capacitance of 173 Fg-1 was obtained at 12mAg-1.

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Post Lithium-ion batteries : Cristina Flox
Authors : Francesca Soavi1,2,3,4*, Alessandro Brilloni1,2,3,4, Francesca De Giorgio3,4,5, Federico Poli1,2,3,4
Affiliations : 1 Department of Chemistry “Giacomo Ciamician”, Alma Mater Studiorum Università di Bologna, Via Selmi 2, Bologna 40126, Italy 2 ENERCube, Centro Ricerche Energia, Ambiente e Mare, Centro Interdipartimentale per la Ricerca Industriale Fonti Rinnovabili, Ambiente, Mare ed Energia (CIRI -FRAME), - Alma Mater Studiorum University of Bologna, Viale Ciro Menotti, 48, 48122 Marina di Ravenna RA (RA) 3 BETTERY Srl, Via C. Pisacane 56, Massafra 74016, Italy 4 National Reference Center for Electrochemical Energy Storage (GISEL) - INSTM, Via G. Giusti 9, 50121 Firenze (Italy) 5 Consiglio Nazionale delle Ricerche, Istituto per lo Studio dei Materiali Nanostrutturati (CNR-ISMN), via Piero Gobetti 101, Bologna, 40129, Italy

Resume : Lithium-Air (O2) batteries are considered as one of the next generation batteries, due to their very high specific energy. In parallel, Redox Flow Batteries (RFBs) are getting much attention in the energy transition because of their highly flexible design that enables the decoupling of energy and power. However, commercial RFBs still suffer from low energy density. One of the solutions proposed to increase the energy density is the combination of the high energy density of the Li/O2 battery with the flexible and scalable architecture of redox flow batteries in semi-solid flow Li/O2 batteries. The challenging activities on materials and components development and prototyping of semi-solid flow Li/O2 batteries are presented and discussed.

Authors : Deepa Singh* (1), A Baby (1,2), & Prabeer Barpanda (1)
Affiliations : (1) Indian Institute of Science, Bangalore, India; (2) University of Illinois at Urbana Champaign (UIUC), IL, USA.

Resume : Investigation of Zinc-based Spinels & (Pyro)phosphates for Zn-ion and Zn-air Batteries Deepa Singh* (1), A Baby (1,2), & Prabeer Barpanda (1) (1) Indian Institute of Science, Bangalore, India; (2) University of Illinois at Urbana Champaign (UIUC), IL, USA. * Abstract Although Li-based batteries are the undeniable leaders in the portable energy storage sector, it is difficult to replicate their success in large-scale stationary energy storage due to the scarcity of Li, high cost, and the inclusion of non-aqueous electrolytes, which make them relatively perilous and inefficient. Recently, aqueous Zn-ion batteries (ZIBs) have emerged as alternate candidates featuring the inherently safe nature of metallic Zn anode and its unique properties.1 Ideal spinel structure is suggested to be incompetent for reversible intercalation of Zn2+ due to higher electrostatic repulsion arising from its dipositive nature. Hence, many synthesis routes are adopted to synthesize spinels that incorporate cation deficiency or cumbrous pathways to enhance Zn2+ (de)intercalation. Herein, we report an economical, fast, and template-free solution combustion synthesis of ZnMn2O4 (ZMO), ZnCo2O4 (ZCO), and ZnMnCoO4 (ZMCO) nanostructured spinels. For the first time, reversible Zn2+ (de)intercalation is observed for ZMCO cathode (ca. 1.5 V vs. Zn2+/Zn) using a low-cost ZnSO4 electrolyte with MnSO4 additive to suppress Mn dissolution from the cathode.2 On another note, highly efficient bifunctional activity is desirable for high energy-density zinc-air batteries. The above-mentioned spinels along with zinc substituted (pyro)phosphates ZnCo2(PO4)2 (ZCP1) and ZnCo2P2O7 (ZCP2) have been examined as bifunctional electrocatalysts in an alkaline medium (0.1 M KOH). The Oxygen reduction reaction (ORR) activity of ZMCO is found to be comparable (onset potential: 0.94 V, the diffusion-limited current density: 5.93 mA/cm3) to existing literature. For the first time, ZCP1 & ZCP2 are shown to exhibit promising stable bifunctional electrocatalytic activities, leading to their application in Zn-air batteries.3 The synthetic, structural, and electrochemical activity of these spinels and phosphates will be described synergizing various experimental and computational tools. References (1) Song, M.; Tan, H.; Chao, D.; Fan, H, J. Recent advances in Zn-Ion batteries. Advanced Functional Materials 2018, 28(14), 1802564. (2) Baby, A.; Senthilkumar, B.; Barpanda, P. Low-cost Rapid Template-free synthesis of nanoscale zinc Spinels for energy storage and electrocatalysis applications. Applied energy materials. 2019, 2(5), 3211-3219 (3) Baby, A.; Singh, D.; Murugesan, C.; Barpanda, P.(2020). The design of zinc-substituted cobalt (pyro) phosphates as efficient bifunctional electrocatalysts for zinc-air batteries. Chemical Communications, 2020, 56(60), 8400-8403.

Authors : Macrelli, A.*(1), Casari, C.S.(1), Li Bassi, A.(1), Russo, V.(1) & Bozzini, B.(2).
Affiliations : (1) Micro- and Nanostructured Materials Lab (NanoLab), Department of Energy, Politecnico di Milano, 20133 Milano, Italy; (2) Battery Materials Engineering Laboratory (BMEL), Department of Energy, Politecnico di Milano, 20156 Milano, Italy. * lead presenter

Resume : Rechargeable zinc-ion batteries (ZIBs) are innovative and promising devices for electrochemical energy storage. Compared to traditional Li-ion technology, the use of a Zn metal anode in combination with an aqueous electrolyte is advantageous in terms of safety, sustainability, cost, ease of preparation, and availability of raw materials. However, several issues are still to be solved, including the risk of Zn corrosion and/or shape change and the instability of the water medium. In addition, a few cathodic materials are currently available, such as Mn and V oxides, V phosphates, and Prussian blue analogues, for which a clear understanding of the electrochemical mechanism is still lacking. A deeper investigation into the electrochemical mechanism is enabled by thin films, which are suitable as model systems and open the possibility of microbatteries. Zn manganites could be effectively used as cathode materials to provide Zn2+ ions thanks to low cost, abundance, environmental benignity, and relatively high redox potential. However, the available literature is scarce and the exact storage mechanism, possibly involving structural changes, phase transitions, precipitation, and proton insertion, is not fully clarified. Here, we report on the synthesis of spinel ZnMn2O4 thin films by Pulsed Laser Deposition (PLD) as candidates for aqueous ZIBs. The versatility of PLD allows the exploration of several thin film structures and morphologies at the nanoscale, which could alleviate volume changes and positively affect the kinetics of the charge transfer, reducing the diffusion path for electrons and ions, thus compensating for poor electrical conductivity without the use of any binder or conductive agent. For example, the presence of an oxygen background gas during deposition permits one to tune the film nano-porosity, and hence its density and surface area, while the post-process annealing temperature allows one to vary the degree of crystallinity of the film and the size of the crystalline grains. The effect of deposition parameters on the film morphology, stoichiometry and vibrational/optical properties is explored by Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDX), Raman, and ultraviolet-visible (UV-VIS) spectroscopies, as well as the effect of annealing temperature, atmosphere, and duration. We then discuss preliminary measurements correlating the different film structures and morphologies to the electrochemical behaviour. The use of in situ Raman spectroscopy allows the characterization of vibrational properties during the application of electrochemical polarization. As a result, one can probe the phase evolution of the cathode material during charge/discharge in slightly-acidic aqueous electrolyte and correlate it to the electrochemical reactions occurring in spinel ZnMn2O4.

Authors : Puja De, Joyanti Halder, Surbhi Priya, Amreesh Chandra
Affiliations : Department of Physics, Department of Energy Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur-721302, India

Resume : One of the most widely explored paths to reduce the cost of electrochemical storage systems is the replacement of current lithium metal with alternative metal anodes. Aluminum-ion batteries are rapidly gaining momentum for use in the next generation energy storage industry. Aluminum is the most abundant metal in the Earth’s crust, with a four and seven times larger volumetric capacity compared to lithium and sodium respectively. Additionally, the three-electron redox reaction (Al+3) and the smaller ionic radius (0.0535 nm) of aluminum offer the path to achieve higher specific energy and power. But, exploring compatible and high-performance cathode materials for rechargeable aluminum ion battery is a key challenge. In this paper, we discuss the electrochemical performance of V2O5 as a cathode material for aluminum ion battery in AlCl3 aqueous solution. The nanostructure of V2O5 was synthesized via hydrothermal synthesis protocol. The preliminary physiochemical characterization of synthesized V2O5 was performed using various techniques. The electrochemical properties were investigated by cyclic voltammetry and charge-discharge measurements in 0.5 M AlCl3 aqueous electrolyte. The V2O5 cathode delivered an initial discharge capacity of ~ 50 mAh g-1 at high current density of 1000 mA g-1 and the capacity was maintained over 200 cycles. The high energy storage mechanism of V2O5 can be attributed to the facile intercalation and deintercalation of the tri-valent Al+3 ions from the electrolyte through the electrode material during discharging and charging processes, respectively. Further, the V2O5 cathode fabricated in this work is of low cost with high safety, making it a useful material for aqueous aluminum ion batteries.

Authors : Bodin C.* (1) (2), Forero-Saboya J.D. (1), Yousef I. (3), Davoisne, C. (2) (4), Dedryvère R. (2) (5) & Ponrouch A. (1) (2).
Affiliations : (1) Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Campus UAB, 08193 Bellaterra, Spain (2) ALISTORE - European Research Institute - CNRS FR 3104 - Hub de l’Energie - 80039 Amiens - France (3) MIRAS Beamline, ALBA Synchrotron Light Source, Carrer de la Llum 2-26, 08290 Cerdanyola del Vallès, Spain (4) Laboratoire de Réactivité et Chimie des Solides, Université de Picardie Jules Verne, CNRS UMR7314, 33 rue Saint Leu, 80039 Amiens, France (5) IPREM, E2S-UPPA/CNRS/ Université de Pau & Pays de l’Adour, 64000 Pau, France

Resume : New battery technologies have received increased attention in recent years, especially those based on the use of divalent cations such as calcium and magnesium. Their high abundance (calcium and magnesium being, respectively, the 5th and 8th most abundant element in the earth crust) and the possible safe use of metal anodes could result in more sustainable devices with lower cost and higher energy density systems when compared to Li-ion. Feasibility of plating/stripping of calcium metal has been demonstrated recently [1] in very few organic electrolyte formulations. In all cases, some degree of electrolyte reduction and formation of passivation layer were reported. [2] In particular, using Ca(BF4)2 in a mixture of carbonate solvents, a fully conformal passivation layer is formed at the surface of the metal anode. Yet this layer allows for Ca plating and stripping, thus exhibiting similar behavior as a solid electrolyte interphase (SEI). However, the nature and composition of such layer remain mostly unknown. In this communication, an in-depth analysis of the SEI will be presented. The influence of the electrolyte formulation (salt, solvent and additive) on the formation of the SEI and how it affects Ca plating and stripping kinetics were investigated. Among other techniques, XPS, EELS and ToF-SIMS measurements allowed to detail the composition of the SEI. The homogeneity, the morphology and the microstructure were studied by means of TEM and synchrotron-based µFTIR microspectroscopy. [1] M.E. Arroyo-de Dompablo, A. Ponrouch, P. Johansson, M.R. Palacín, Achievements, Challenges, and Prospects of Calcium Batteries, Chem. Rev. 2020, 120 6331–6357. [2] Forero-Saboya, J. D., Tchitchekova, D. S., Johansson, P., Palacín, M. R., Ponrouch, A., Interfaces and Interphases in Ca and Mg Batteries. Adv. Mater. Interfaces 2021, 2101578.

10:30 Discussion    
10:45 Break    
Authors : Romain Wernert, Antonella Iadecola, François Fauth, Laure Monconduit, Dany Carlier, Laurence Croguennec
Affiliations : Université de Bordeaux, CNRS, Bordeaux INP, ICMCB UMR CNRS #5026, Pessac, F-33600, France; RS2E, Réseau Français sur le Stockage Electrochimique de l’Energie, FR CNRS #3459, Amiens F-80039 Cedex 1, France; CELLS-ALBA synchrotron, E-08290, Cerdanyola del Vallès, Barcelona, Spain; ICGM, Univ. Montpellier, CNRS, Montpellier, France; Université de Bordeaux, CNRS, Bordeaux INP, ICMCB UMR CNRS #5026, Pessac, F-33600, France;Université de Bordeaux, CNRS, Bordeaux INP, ICMCB UMR CNRS #5026, Pessac, F-33600, France

Resume : Among positive electrode materials for K-ion batteries, KVPO4F vanadium phosphate fluoride has been proposed as a high voltage material with a theoretical capacity of 131 mAh·g-1 at an average voltage of 4.3 V. Such properties confer a theoretical energy density of 560 Wh·kg-1 at the material scale, which is the same as largely commercialized LiFePO4. However in practice only ~100 mAh·g-1 can be reversibly reached, corresponding to 0.8 K exchanged. In this work, we investigated whether the impossibility to reach full capacity originates from structural constraints or kinetic limitations. K0VPO4F synthesized by chemical deintercalation of potassium from KVPO4F was characterized by the means of X-ray diffraction and MAS-NMR and XAS spectroscopies. It was evidenced that the polyanionic framework was conserved despite contraction of the unit cell volume by 9%. Further electrochemical characterizations of K0VPO4F led us to conclude that the failure to reach theoretical capacity is due to a competition between electrochemical de-insertion on one hand and side reactions driven by the instability of the electrolyte above 4.5 V on the other hand. This work was also extended to anion substituted KVPO4F0.5O0.5 and similar conclusions are drawn. This study also highlights the interest of combining a chemical K insertion/de-insertion to the electrochemical measurements to investigate the structure and reactivity of active materials at the frontier of their stability.

Authors : Vincenzo Palermo1,3 Jinhua Sun1, Matthew Sadd1, Philip Edenborg1, Henrik Grönbeck1, Peter Thiesen2, Zhenyuan Xia1, Vanesa Quintano1, Ren Qiu1, Aleksandar Matic1
Affiliations : 1Chalmers University of Technology, Göteborg, Sweden. 2Accurion GmbH, Stresemannstraße 30, Göttingen 37079, Germany. 3Institute of Organic Synthesis and Photoreactivity (ISOF), National Research Council of Italy (CNR), Bologna, Italy.

Resume : Sodium, in contrast to other metals, cannot intercalate in graphite, hindering the use of this cheap, abundant element in rechargeable batteries. Here, we report1 a nanometric graphite-like anode for Na+ storage, formed by stacked graphene sheets functionalized only on one side, termed Janus graphene. The asymmetric functionalization allows reversible intercalation of Na+, as monitored by operando Raman spectroelectrochemistry and visualized by imaging ellipsometry. Our Janus graphene has uniform pore size, controllable functionalization density, and few edges; it can store Na+ differently from graphite and stacked graphene. Density functional theory calculations demonstrate that Na+ preferably rests close to -NH2 group forming synergic ionic bonds to graphene, making the interaction process energetically favorable. The estimated sodium storage up to C6.9Na is comparable to graphite for standard lithium ion batteries. Given such encouraging Na+ reversible intercalation behavior, our approach provides a way to design carbon-based materials for sodium ion batteries. 1 Science Advances 2021; 7 : eabf0812

Authors : Gustav Åvall, Youhyun Son, Guillermo Alvarez Ferrero, Knut Arne Janßen, Philipp Adelhelm
Affiliations : Institut für Chemie, Humboldt Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany;Institut für Chemie, Humboldt Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany;Institut für Chemie, Humboldt Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany;Institut für Chemie, Humboldt Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany;Institut für Chemie, Humboldt Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany, Joint Research Group Operando Battery Analysis, Helmholtz-Zentrum Berlin, Hahn-Meltner-Platz 1, 14109 Berlin, Germany

Resume : Sodium-ion batteries (SIBs) is one of the more promising battery technologies that are starting to see commercialisation, were the low cost, abundance of necessary raw materials, higher safety and power and similar energy densities compared to lithium-ion batteries (LIBs) are often mentioned as their key advantages. SIBs, due to their great similarities with LIBs have seen rapid development. One of the key differences, however, is the carbonaceous negative electrode, where SIBs, due to Na+ not forming thermodynamically stable binary intercalation compounds with graphite, the anode of choice for LIBs, are forces to use primarily hard carbons. But, it was recently discovered by Jache et al. that Na+ can form stable ternary graphite intercalation compounds through a solvent co-intercalation mechanism, thus enabling the use of graphite in SIBs [1]. This sparked several follow-up studies exploring solvent co-intercalation [2], which have shown that the system has great rate capabilities and remarkable cycle life but is plagued by a large volume expansion and poor energy density due to the low specific capacity of the system and the high potential vs. sodium where the co-intercalation reaction happens. Even after all these investigations, the question of how many solvent molecules are intercalated along with the cation, and thus the stoichiometry of the redox reaction, was never settled. Here, we present a novel electrochemical method to directly measure the number of solvents that are brought along by the cation into the graphite host structure by investigating glyme based electrolytes. The knowledge from these measurements enabled us to rationally design new electrolytes, composed of glymes mixed with another co-solvent, that both increases the energy density of the system by lowering the voltage where co-intercalation occurs, and by establishing a new low voltage plateau showing that these electrolytes enable a new electrochemical reaction, while also reducing the cost of the electrolyte. The impact of the new electrolytes on the structure of graphite is studied using operando dilatometry and XRD – showing that the detrimental volume expansion that occurs upon co-intercalation is greatly reduced using these new electrolytes. The local electrolyte structure is investigated with ab initio molecular dynamics, showing how the structure and stability of the solvation shells changes with the ratio of salt to glyme, glyme per co-solvent, and glyme to carbon, which we connect with the observed altered electrochemical behaviour and the structural changes of graphite upon sodiation. The experimental and computational studies together giving a comprehensive view of the system. [1] B. Jache, P. Adelhelm, Angew. Chem. Int. Ed. 2014, 53, 10169-10173, DOI: 10.1002/anie.201403734 [2] J. Park, Z-L. Xu, K. Kang, Front. Chem., 2020, 8:432, DOI: 10.3389/fchem.2020.00432

Authors : Fasulo, F. *(1), Massaro, A. (1), Muñoz-García, A.B. (2) & Pavone, M. (1).
Affiliations : (1) Department of Chemical Sciences, University of Naples Federico II, Via Cintia 21, 80126 Napoli, Italy (2) Department of Physics “E. Pancini”, University of Naples Federico II, Via Cintia 21, 80126 Napoli, Italy * lead presenter

Resume : Na-ion batteries (NIBs) are promising devices to replace the prevailing Li-ion based technologies (LIBs) for large-scale energy storage, thanks to cheap and easily available sodium raw materials [1]. However, the large Na+ radius hampers a reversible sodiation-desodiation of common LIB negative electrodes [2] and great research efforts are devoted to development and optimization of highly effective NIB anode materials [3]. In this context, TiO2 anatase has been proposed as a possible anode material for both NIB and LIB devices because it ensures low operation voltage, high capacity, nontoxicity, and low cost. Recent experiments highlighted that the performances of anatase nanoparticles (NPs) as NIB negative electrode depend on the exposed NP surfaces: the (100) and (001) facets being much more effective than the most stable (101) surface [6]. The behavior of these different surface terminations has been ascribed to a convenient accommodation of the large cations without large crystalline lattice distortion for the (100) surface, and to an easy insertion to the sub-surface layer for the (001) [7]. However, in operando conditions should also consider the presence of an electric field, which is neglected in common DFT simulations of anatase-Na+ interfaces. Here, we report a first-principles investigation on the Na+ adsorption and intercalation on exposed TiO2 anatase-crystal facets, the (101), (100) and (001), under the influence of an external electric field. Following computational approach pioneered for TiO2 by Selloni and coworkers [8], we applied the PBE+U level of theory [9,10] and we simulated the electric field in the direction perpendicular to the surface by adding a sawtooth-like potential [12] to the bare ionic potential. We found that the direction of the applied field can have a significant influence on the Na uptake, with the insertion more favorite at electric field opposite to z-axis. Moreover, the electric field affects the Ti4+/3+ redox couple, that is involved during Na+ intercalation reaction at the NIB electrode. Overall, our findings will improve the current understanding of electrochemical reactions at NIB electrode surface and will help the further design of new effective anodes for this promising energy storage devices. [1] Abraham, K.M.; ACS Energy Lett. 2020, 5, 11, 3544 [2] Lu, Y.; et al. Adv. Energy Mater., 2018, 1702469. [3] Li, L.; et al. Energy Environ. Sci., 2018, 11, 2310. [6] Longoni, G.; et al. Nano Lett., 2017, 17, 992. [7] Massaro, A.; et al. Nanoscale Adv., 2020, 2, 2745. [8] Selçuka, S.; Selloni, A.; J. Chem. Phys., 2014, 141, 084705. [9] Perdew, J.P.; Burke, K.; Ernzerhof, M.; Phys. Rev. Lett., 1996, 77, 3865. [10] Anisimov, V.I.; Zaanen, J.; Andersen, O.K.; Phys. Rev. B, 1991, 44, 943. [12] Kunc, K.; Resta, R.; Phys. Rev. B, 1986, 34, 7146.

12:00 Discussion    
12:15 Lunch    
Post Lithium-ion batteries : Olivier Crosnier
Authors : Lochab, S.*(1), Singh, D.(2), Jayanthi, K.(3) Navrotsky, A.(3), Ahuja, R.(2) & Barpanda, P.(1)
Affiliations : (1) Indian Institute of Science, Bangalore, India; (2) Uppsala University, Upsala, Sweden; (3) Arizona State University, Arizona, United States;

Resume : The evolution of energy storage devices which are inexpensive and possess large capacity are important for our future energy needs. Battery active materials, which are economic and can be produced via a facile synthesis, are extensively explored.1 In current work, NASICON type NaFe¬2PO4(SO4)2 was examined as a battery insertion material for rechargeable batteries.2, 3 It was synthesized via a facile spray drying method for the first time with spherical morphology, for usage as cathode material in Li-ion as well as Na-ion batteries. Electron microscopy confirmed the formation of nanospherical morphology. Vibration spectroscopy analysis (FTIR, Raman and UV vis) confirmed the presence of sulphate and phosphate groups. Isothermal acid solution calorimetry technique was employed to find the dissolution enthalpy for the material considering enthalpy of formation of reactants via Hess’s Law. Theoretical and experimental studies were done to get a better understanding of the electrochemical behavior, along with the underlying redox mechanisms. Theoretical calculations like density functional theory (DFT), bader charge analysis, bond valence sum energy (BVSE) were employed to predict various fundamental properties and the redox involved. Electrochemical performance for both Li and Na ion batteries was tested by cyclic voltammetry, galvanostatic cycling and electrical impedance spectroscopy. The results indicate that NaFe¬2PO4(SO4)2, employing Fe+3/+2 redox couple, is a good intercalating cathode for both Li and Na batteries in the voltage range of 2.0 V to 4.5 V with good capacity and cycling stability. Keywords: polyanions, capacity, cathode, crystal structure, intercalation, single particle model 1. Tarascon, J.-M. Key challenges in future Li-battery research. Phil. Trans. R. Soc. A. 2010, 368 (1923), 3227-3241. 2. Yahia, H. B.; Essehli, R.; Amin, R.; Boulahya, K.; Okumura, T.; Belharouak, I. J. J. o. P. S. Sodium intercalation in the phosphosulfate cathode NaFe2 (PO4)(SO4) 2. 2018, 382, 144-151. 3. Shiva, K.; Singh, P.; Zhou, W.; Goodenough, J. B. NaFe 2 PO 4 (SO 4) 2: a potential cathode for a Na-ion battery. Energy Environ. Sci. 2016, 9 (10), 3103-3106.

Authors : A. Petrongari (a), M. Tuccillo (a), A. Latini (a), S. Brutti (a)
Affiliations : (a) Dipartimento di Chimica, Università di Roma La Sapienza, P.le Aldo Moro 5, 00185 Roma (Italy)

Resume : Sodium metal batteries (SMBs) have recently gained attention as promising energy storage systems. SMBs are a competitive technological paradigm compared to the state-of-the-art lithium ion batteries thanks to the high specific capacity of sodium metal, i.e. 1166 mAh/g, and the Na+/Na0 low redox potential of -2.71V vs. SHE. Dendrite growth of sodium is the main drawback that hinders the development of SMBs. Herein, we propose Na-SG-II as an active material in order to obtain dendrite-free sodium metal anodes. Na-SG-II is a functionalized silica gel material with extended porosity that can act as a host for sodium plating/stripping to mitigate the dendrite growth. Na-SG-II is a dual-phase material obtained by absorption of liquid Na into nanostructured silica gel and subsequent heating up to 400°C for 15h, leading to an open structure constituted by Na4Si4 and Na2SiO3. Na-SG-II has been incorporated in composite electrodes using a conductive carbon additive and polymeric binders. Binders with different mechanical properties, PVDF and PEO, are used in order to point out their impact on the electrochemical performance in batteries. Galvanostatic tests of the Na-SG-II electrodes in half cells versus Na anodes demonstrates that the active material allows an highly reversible sodium plating/stripping with 100% of coulombic efficiency for at least 200 cycles at room temperature. The analysis of the experimental overpotentials at various applied currents by the Tafel equations allowed to estimate the exchange currents J0 and the symmetry factors β. Apparently PEO-based electrodes outperform in terms of electrokinetic activity the PVDF-based ones.

Authors : Arianna Massaro, Ana Bélen Muñoz-García, Michele Pavone
Affiliations : Department of Chemical Science, University of Naples “Federico II”, Naples, Italy Department of Physics “E. Pancini”, University of Naples “Federico II”, Naples, Italy

Resume : Na-ion batteries (NIBs) are rapidly emerging as promising post-Lithium technology for large-scale applications, thanks to the wide availability and low cost of raw materials [1]. Research efforts aiming at developing an effective deployment of NIB technology are mainly focused on the design and optimization of highly efficient active materials, which for the cathode side seem to rely on enhanced energy density and stability [2]. Layered transition metal oxides (NaxTMO2) have shown outstanding performances as high-energy cathode materials in NIB cells and exhibited the chance to attain larger specific capacity by enabling anionic reactions at high operating voltage [3, 4]. This represents a new paradigm in the development of positive electrodes, but the O2-/O2n-/O2 redox processes need to be finely controlled to prevent the release of molecular oxygen and thus huge capacity loss. We report a first-principles investigation of P2-type Mn-defective layered oxides with different metal doping at the TM site (e.g., Ni or Ni and Fe) by means of PBE+U-D3(BJ) calculations. Structural and electronic features are dissected for each redox-active element in NaxNi0.25Mn0.68O2 (NNMO) and NaxFe0.125Ni0.125Mn0.68O2 (NFNMO) materials as function of sodiation degree corresponding to different states of charge. We address the oxygen redox activity by considering the formation of oxygen vacancies and dioxygen metal complexes at low Na loads (i.e., high voltage range). Low-energy superoxide moieties with different coordination geometries are predicted to be formed at x Na = 0.25 in Mn-deficient sites, while the x Na = 0.125 content enables the release of molecular O2 via preferential breaking of Ni-O bonds. Mechanistic insights show that dioxygen formation is driven by the M-O covalency and unveil that O2 loss can be effectively suppressed by Fe doping. Our findings pave the route for the rational design of high-energy NaxTMO2 cathodes that feature enhanced reversible capacity and thus boost the development of efficient NIB devices. These outcomes are collected in a recent publication on ACS Energy Letters [5]. References: [1] B. Dunn, et al., Science, 334(6058), 928-935 (2011) [2] Y. Huang, et al., ACS Energy Lett., 3(7), 1604-1612 (2018) [3] Q. Wang, et al., Nat. Mater., 20(3), 353-361 (2021) [4] M. Ben Yahia, et al., Nat. Mater., 18(5), 496-502 (2019). [5] A. Massaro, et al. ACS Energy Lett., 6, 2470-2480 (2021).

Authors : Egorov E.V.(1,2,3), Egorov V.K.(1)
Affiliations : (1) Institute of Microelectronics Technology Russian Academy of Science (IMT RAS) (2) Institute of Radio Engineering and Electronics Russian Academy of Science (IRE RAS) (3) Financial University under the Government of the Russian Federation

Resume : Generally accepted approaches for the electric energy production on base the nuclear technology includes an electrical yield use appeared in result of heavy nuclei disintegration, by application of the thermonuclear fusion, “cold” nuclear fusion at Pd and Ti atoms presence and in result of the beta decay. The thermonuclear technology intends to get over the Coulomb barrier by use the high-temperature plasma. This approach, in principle, allows to expect an appearing of nuclear power facility in future but its perspective is misty. The “cold” nuclear fusion is oriented on conditions search for the under barrier nuclear reaction procession in result of the tunneling effect. This approach was realized on practice but is characterized by very low efficiency and high unpredictability. At the same time, there is available the alternative approach to direct nuclear interaction realization allowed to evade the Coulomb interaction. It can be achieved on base of consecutives of the radiation fluxes waveguide-resonance propagation phenomenon in combination with the corpuscle-wave dualism principle use. The phenomenon of radiation fluxes waveguide-resonance propagation can be realized when radiation fluxes have possibility to excite in the propagation space the uniform interference field of radiation standing wave. Optical, X-ray and neutron quasimonochromatic radiation fluxes form these conditions when the width of its propagation space will be smaller as half of the radiations coherence length. The phenomenon peculiarities study showed that the interaction between independent radiation fluxes is possible in result of mutual influence of uniform interference fields excited by these fluxes. At the sane time, owing to the corpuscle-wave dualism atomic and molecular beams can excite principle similar uniform interference fields. By this means, one can get similar fields for atomic and molecular quasimonochromatic fluxes of hydrogen, deuterium, tritium and other elements and search of its interaction conditions. So, in frame of our paradigm the task of nuclear fusion reaction realization will be not connected with Coulomb barrier overcoming and will be directed on search of specific conditions for interaction of atomic and molecular beams through the mutual influence of uniform interference fields excited by these fluxes. Some peculiarities of the similar interaction is discussed in the report.

16:00 Discussion and Closing Remarks    

No abstract for this day

Symposium organizers
Adélio MENDESFaculdade de Engenharia da Universidade do Porto

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Carlos PONCE DE LEON ALBARRANUniversity of Southampton

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Cristina FLOXInstitut de Ciencia de Materials de Barcelona, CSIC

Campus UAB, Barcelona, 08193, Spain

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Olivier CROSNIERUniversité de Nantes

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Volker PRESSERLeibniz Institut für Neue Materialien GmbH

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