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 6.25 Al 0.25 La 3 Zr 2 O 12 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.