EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Thin film solid state batteries can provide a compact and environmentally friendly solution for powering future micro-devices. While few commercial solutions exist, there is a major interest in providing improved performances and capabilities by developing appropriate electrodes with high capacity, stability and fast performance, and electrolytes with a low ionic resistance. Here we present the development of LiMn2O4 (LMO) and Li4Ti5O12 spinel electrodes, and Li1 xAlxTi2-x(PO4)3 electrolyte thin films. The materials have been deposited by means of Large Area Pulsed Laser Deposition (LA-PLD), using multi-layering strategies to compensate for the lithium loss during processing. Exhaustive structural and electrochemical characterization of the layers has been carried out. In particular, recently developed operando spectroscopic ellipsometry (SE) technique has been applied for the study of ion-transport phenomena and for the track of Lithium content and volume expansion during cycling. This procedure allowed to observe the evolution of the layers with a time resolution below 100 ms, with a simple setup and in a non-destructive way. Using this approach, we finally provide information about relevant phenomena such as self-discharge or volume expansion during cycling.