Ex-Situ Electron Microscopy Study of Solid Electrolyte Interphase Formed by Charge-Discharge Reaction of Silicon Negative Electrode in Lithium-Ion Secondary Battery

摘要

A SEI (Solid Electrolyte Interphase) is formed on the surface layer of the negative electrode active material of a lithium ion secondary battery (LIB) during the initial charging process, and its morphology and structure significantly affect performance and safety. in this study, by conducting ex situ experiments, SEM, TEM and STEM-EELS observations were performed on Si negative electrodes under charge state within an actual battery and Si negative electrodes directly charged on a TEM thin film. revealed morphology and structure of the SEI. All of the processes from specimen preparation for electron microscopy observation to specimen transport were performed under non-atmospheric exposure conditions.