Multi‐Physical Field Coupling Mechanisms and Multi‐Scale Design for All‐Solid‐State Lithium Batteries

All-solid-state lithium batteries (ASSLBs) are regarded as a pivotal developmental route for next-generation energy storage technologies owing to their inherent safety and promising high-energy-density capability. Focusing on multi-physical field coupling and aiming to achieve high safety and high energy density simultaneously, this review systematically summarizes the multi-scale design strategies of ASSLBs. At the intrinsic material scale, this work summarizes the performance characteristics, failure mechanisms and optimization approaches of high-voltage/high-capacity cathodes, high-energy-density anodes, and diverse solid-state electrolytes (SSEs). From the electrode-electrolyte interfacial perspective, particular emphasis is placed on the multi-physical field coupling failure evolution of cathode-electrolyte and anode-electrolyte interfaces, alongside the modulation mechanisms of interfacial modification and structural engineering on interfacial contact, ionic conduction, volume variation effects and structural durability. At the full-cell system scale, optimization designs including cell configuration refinement, monolithic integration manufacturing, and synergistic thermal management and safety engineering are elaborated. Finally, addressing the current challenges in the field, such as ambiguous dynamic multi-physical-field coupling fundamentals and the infeasibility of real-time prediction on coupled failure behaviors, this review concludes with prospects for the establishment and implementation of an in-situ multi-physical-field characterization framework, delivering experimental foundations and theoretical guidelines toward the multi-scale synergistic optimization of ASSLBs.