Development of operando hard X-ray photoelectron spectroscopy for all-solid-state batteries and reaction analysis in fluoride ion batteries

Abstract

We have developed operando hard X-ray photoelectron spectroscopy (HAXPES) for all-solid-state batteries taking advantage of the large photoelectron escape depth of several 10 nm. The large escape depth is one of the features of HAXPES. This operando HAPXPES method was applied to reveal the reaction mechanism of fluoride shuttle batteries which are taken attention as one of the post lithium-ion batteries. The measurement was performed while charging and discharging a Cu-based model fluoride shuttle battery grown on a solid electrolyte substrate, and the formation and deformation of CuF₂ were observed from both Cu 2p and F 1s during the charge and discharge process, respectively.