In situ electron holography for characterizing Li ion accumulation in the interface between electrode and solid-state-electrolyte

Abstract

An intensive understanding of the Li-ion transport mechanism in solid-state-electrolytes (SSEs) is crucial for the buildup of industrially scalable solid-state batteries. Here, we report on the charge distribution near the electrode/SSE interface and the Li-ion transport in solid-state-electrolyte Li₇La₃Zr₂O₁₂ (LLZO) via real-time in situ electron holography and electron energy loss spectroscopy (EELS) monitoring in a working cell model. The reconstructed phase image unravels the behavior of Li ions beneath the electrode during the charging process. The inhomogeneous accumulation occurs at charging, and the Li ions remained there after the reversal operation. Grain boundary (GB) may be the negative influence on the ion conductivity. These findings provide an in-depth understanding of the interfacial mechanism, and thus improve the optimized design of solid-state batteries.