All-solid-state lithium(-ion) microbatteries for high temperature applications

Published : 24 April 2017

The aim of this thesis is the development of all-solid-state microbatteries suitable for high temperature operation (80-200°C), as power supplies for sensors located in severe environments.

The first part of the work will aim at assessing the behaviour (electrochemical cycling, impedance) of conventional Li/LiPON/LiCoO2 microbatteries operating at various temperature, as a function of time, cycles and state-of-charge, in order to determine the level of performance of these devices and to highlight thermally-activated aging phenomena. Then, a thorough physico-chemical characterization of these microbatteries and their constituents will be carried out by various means (STEM-EELS, SEM-FIB, Auger nano-probe, XRD, Raman spectroscopy, XPS, ToF-SIMS,…) in order to identify the origin of these phenomena.

The second part of the thesis work will focus on the improvement of the microbattery design – especially by means of a proper choice of electrode and/or electrolyte materials – able to enhance the robustness of the device and to make it more appropriate to specific purposes. Therefore, new thin film electrode/electrolyte materials will be prepared by PVD (sputtering) in a dedicated equipment connected to a glove-box. The thermal stability of these materials will be assessed (DSC, XRD, Raman spectroscopy,…) at first individually, then for couples of electrode/electrolyte materials in order to highlight the possible evolution of their interface (XPS, ToF-SIMS, Auger spectroscopy). Finally, the more promising systems (secondary or primary batteries) will be completed and their electrochemical behaviour at high temperature will be studied.

The thesis will be carried out at ICMCB in Bordeaux (Laboratory of Condensed Matter Chemistry) in a joint CEA/CNRS team, having expertise in the fields of all-solid-state microbatteries and thin film materials.

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