Pressure and rate dependency of phase evolution and utilization of Si in solid-state batteries

The main objective is to investigate the phase, microstructure and elastic strain evolution in Si-anode based solid-state batteries (SSBs) as a function of the applied stack pressure as well as the charge-discharge rate by using operando XRD using our newly developed operando set-up at the BM31. Si is one of the most promising anode materials due to its high specific capacity. Although SSBs utilizing Si show attractive application prospects, current results are still in an infant state. In particular, the phase evolution, comprising amorphization and re-crystallization during charge and discharge, as well as the actually amount of Si utilization, which is expected to by significant influenced by stack pressure, are lacking in understanding. This study will shed light on the underlying processes taking place during operation and will therefore propel the battery field toward engineered silicon anodes that meet the requirements for large-scale adoption of SSBs.