All-solid-state thin film lithium microbatteries (thickness ~10 µm) are currently developed as electrical energy storage and power supply systems for miniaturized electronic devices (autonomous sensors, MEMS, smart cards, ‘perpetual energy’ modules,…). One specificity of these batteries is to use a glassy inorganic electrolyte conducting Li+ ions, deposited by RF magnetron sputtering. Today, LiPON type materials (lithium phosphorus oxynitrides) are mainly used for this purpose. Nevertheless, their rather low ionic conductivity (~3.10-6 S.cm-1) appears now as a major obstacle for the use of microbatteries in a growing number of emerging devices.

Hence, the aim of the work will be the development of new glassy inorganic electrolytes able to meet both conductivity and process requirements for the realization of improved Li-ion microbatteries. These sulfide or oxide type materials, based on network formers comprising a metal or metalloid element, will be deposited as thin films by radio-frequency magnetron sputtering of home-made targets, using an equipment connected to a glovebox. Different strategies dealing with materials composition (type of network former, synergic effect of mixed formers) and/or structure (glass-ceramics) will be carried out to get optimal performance in terms of ionic and electronic transport, chemical and electrochemical stability. Numerous techniques will be used to determine the chemical composition of the thin films (ICP, Rutheford Back-scattering Spectroscopy, Electron Probe Micro Analysis, Auger spectroscopy, …) and to characterize their structure (X-ray diffraction, Raman spectroscopy, XPS, TEM,…) and their morphology (MEB-FEG). Impedance spectroscopy measurements performed at different temperatures will allow determining conduction properties (ionic conductivity, activation energy). In the course of this study, the behavior of selected electrolytes will be assessed in real microbatteries. The work will be carried out in the CEA/CNRS team located at ICMCB (Bordeaux).

This position is open until it is filled.

Department: Département Composants Silicium (LETI)
Laboratory: Laboratoire Composants micro stockage de l’Energie
Start Date: 01-10-2015
ECA Code: SL-DRT-15-0103
Contact: frederic.lecras<στο>cea.fr