Resolving Real-Time Interfacial Dynamics on Garnet-Based Solid-State Electrolytes via Snapshot Operando XPS

Unveiling interfacial dynamics in solid-state batteries under operando conditions remains a major challenge in solid-state battery research, largely due to the limited temporal resolution of conventional analytical techniques. Here, we introduce a laboratory-based operando x-ray photoelectron spectroscopy (XPS) methodology employing a snapshot spectral acquisition mode that enables real-time tracking of interfacial chemistry in solid-state battery systems. The approach is demonstrated by monitoring electrochemical lithiation occurring in Sb and Cu films deposited on the surface of the Li_6.25Al_0.25La₃Zr₂O₁₂ solid-state electrolyte (SSE). Understanding these processes is critical for developing effective SSE/Li interfacial layers that improve the cycling stability of lithium metal anodes and for advancing anode-free solid-state battery architectures. When combined with the static in-situ non-destructive depth-profiling capabilities of hard x-ray photoelectron spectroscopy (HAXPES), this methodology has strong potential to become a key analytical approach for probing buried interfaces in solid-state batteries under operando conditions.