Descriptif des activités de recherche

Fundamental study of interfaces in all solid state batteries (ASSB) by environmental scanning electron microcopy (ESEM). Conventional LIBs use organic liquid electrolytes (OLEs), which consist of a lithium salt such as lithium hexafluorophosphate (LiPF6) dissolved in organic solvents such as ethylene carbonate (EC) and dimethyl carbonate (DMC). The high flammability of organic solvents (EC flash point 150 °C and DMC flash point 18 °C) presents safety risks during battery operation. Further, OLEs are depleted during charge/discharge cycles, due to the repeated breakdown and reformation of solid electrolyte interphase (SEI) films. Due to the limitations of the aforementioned OLEs, current LIB technologies are not able to meet the higher energy density and better safety required for existing and new applications. The ideal battery, that meets these new needs, will be made with a solid-state electrolyte (SSE), a Li metal anode and a high-voltage cathode, what is known as an all-solid-state battery (ASSB). Most SSEs are nonflammable and have a wider operating temperature range, making them much safer than their liquid counterparts in the event of short circuiting. Though ASSB offer many advantages over LIB, they show problems related to interface. It’s extremely important to know what’s cooking at the interface. During this P.hD we will answer problems related to the interfaces in all solid state batteries. The first studied systems will be composed of oxide or sulfur (argyrodite, LISCON, …) as solid electrolyte, carbon (or metallic anode) and LiCoO2 (or LiMn2O4, LiNixCoyMn1-x-yO2) as electrodes. In this aim, the PhD thesis will follow two axes: (i) a fundamental study to understand the influence of parameters (pressure, temperature, particles size, mixture, coating etc …) on the interface quality with a synergistic work with Electrochemistry group, and (ii) the in-situ and operando study in the ESEM of the degradation mechanisms (interphases formation, cracks apparition, …) through the development and the test of home-made and innovative electrochemical cell adapted to the microscopes at the UPJV electron microscopy platform (PME). The obtained results will be compared to post-mortem characterizations at different cycling steps to ensure observation reliability.

Parcours

• Master - Medical and industrial applications of radiations, solar fuels and nanomedicine SERP+ Erasmus Mundus (University Paris Sud /Paris Saclay, 2017-2019)
• Bachelors - Nanoscience and Technology (Shivaji University Kolhapur, 2014-2017)

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Compétences

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