ORALS

SESSION: AdvancedMaterialsWedPM2-R6	4th Intl. Symp. on New and Advanced Materials and Technologies for Energy, Environment and Sustainable Development
Wed Nov, 7 2018 / Room: Guaratiba (60/2nd)
Session Chairs: Hervé Martinez; Xijia Wu; Session Monitor: TBA

15:55: [AdvancedMaterialsWedPM209] Keynote
New Surface Science Investigations for the Knowledge of Electrochemical Energy Storage
Hervé Martinez¹ ; ¹Université de Pau et des Pays de l'Adour - IPREM CNRS UMR 5254, Pau, France;
Paper Id: 9 [Abstract]

It is now generally accepted that the performance of all lithium ion or lithium batteries (including liquid or solid electrolyte) depends on the surface chemistry developed on the electrode / electrolyte interface system. This work presents a contribution to the knowledge of the solid electrolyte interface (SEI) from two different examples: The first one concerns Spinel Li₄Ti₅O₁₂ (LTO) which is considered as a good alternative negative electrode material for Li-ion batteries. The reactivity of LTO toward commons carbonates based electrolytes has been evidenced by surface analysis and an important gassing occurring at the electrode/electrolyte interface was reported. Therefore it is essential to better understand the interfacial phenomena. A precise understanding of the Spinel Li₄Ti₅O₁₂ (LTO) electrode/electrolyte interfaces in relation with batteries (Li₄Ti₅O₁₂/Li half-cells) electrochemical performances is presented. The influence of various parameters (cycling temperature, electrode and electrolyte composition, cycling potential window) upon the SEI formation and dissolution through cycles is investigated. Finally, full cells as Li₄Ti₅O₁₂/LiMn₂O₄ cells having potential assets in term of cost and safety will be investigated, in order to point out the changes in the SEI formation due to interactions between both electrodes. The samples are analyzed using 3 complementary extreme surface characterization techniques XPS-AES-TOF-SIMS (analysis depth 1-10 nm), operating at different spatial resolutions. The second example is related to the recent technological development of miniaturized systems which has induced a strong demand for developing compact power sources with high efficiency and small dimensions that are suitable for portable devices. Among these systems, the lithium microbattery may be relevant for a wide range of applications (microelectronic devices). An all solid state battery LiCoO₂ / LiPON / Li is considered and more specifically the behaviour of the interface between the positive electrode and the solid electrolyte, studied by ion milling cross section / Auger Spectroscopy coupling.

References:
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3. J.B. Gieu, V. Winkler, C. Courriges, H. Martinez (2017) New insights in the characterization of the electrode/electrolyte interfaces within LiMn 2 O 4 /Li 4 Ti 5 O 12 cells, by X-ray Photoelectron Spectroscopy, Scanning Auger Microscopy and Time-of-Flight Secondary Ion Mass Spectrometry. Journal of Materials Chemistry A, 5 (29)
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5. Uhart, J.B. Ledeuil, B. Pecquenard, F. Le Cras, M. Proust, H. Martinez (2017) Nanoscale chemical characterization of solid state microbattery stacks by means of Auger Spectroscopy and ion-milling cross-section preparation. ACS Applied Materials & Interfaces, 9 (38), pp 33238-33249