Deterioration Analysis of Si Composite Anodes for All-Solid-State Batteries during Charge–Discharge by Auger Electron Spectroscopy and Scanning Electron Microscopy with Energy Dispersive Spectroscopy

Silicon (Si) is a promising anode material for lithium-ion batteries owing to its large capacity. Herein, all-solid-state full cells using Si composite anodes and sulfide solid electrolytes were fabricated and their charge–discharge performances were evaluated. From Auger electron spectroscopy and scanning electron microscopy with energy dispersive spectroscopy analyses of the cross section of the full cells, the presence of Li2O in the Si composite anodes was confirmed after the 50th charge–discharge cycle. Further, the relation between the capacity deterioration mechanism of the cells using the Si composite anodes and the generation of Li2O was studied.