A Morphologically Stable Li/Electrolyte Interface for All‐Solid‐State Batteries Enabled by 3D‐Micropatterned Garnet

Abstract Morphological degradation at the Li/solid‐state electrolyte (SSE) interface is a prevalent issue causing performance fading of all‐solid‐state batteries (ASSBs). To maintain the interfacial integrity, most ASSBs are operated under low current density with considerable stack pressure, which significantly limits their widespread usage. Herein, a novel 3D‐micropatterned SSE (3D‐SSE) that can stabilize the morphology of the Li/SSE interface even under relatively high current density and limited stack pressure is reported. Under the pressure of 1.0 MPa, the Li symmetric cell using a garnet‐type 3D‐SSE fabricated by laser machining shows a high critical current density of 0.7 mA cm –2 and stable cycling over 500 h under 0.5 mA cm –2 . This excellent performance is attributed to the reduced local current density and amplified mechanical stress at the Li/3D‐SSE interface. These two effects can benefit the flux balance between Li stripping and creep at the interface, thereby preventing interfacial degradation such as void formation and dendrite growth.