Multiscale Understanding of Anode-Electrolyte Interfaces Challenges in Sulfide-Based All-Solid-State Lithium-Metal Batteries

All-solid-state batteries (ASSBs) offer the promise of enhanced safety and higher energy density compared with conventional liquid-electrolyte systems. However, when employing lithium (Li) metal as the anode, the anode/solid-state electrolyte (SSE) interface remains a critical bottleneck, plagued by poor interfacial contact, chemical and electrochemical instability, and progressive mechanical degradation during cycling. These interfacial challenges are inherently multiscale, originating from atomic-level diffusion and reaction, mesoscale morphological evolution, and macroscale electro-chemo-mechanical interaction. Focusing on sulfide electrolytes, this review systematically elucidates the fundamental origins of these issues and summarizes corresponding mitigation strategies across multiple scales, aiming to bridge the understanding from atomic interactions to device-level behavior and to guide the rational design of the Li/SSE interface for future ASSBs.