Effects of external pressure on all-solid-state batteries: comprehensive review and analysis

All-solid-state batteries (ASSBs) offer next-generation energy storage solutions with high energy density and enhanced safety. A central challenge remains the solid-solid interfacial contact between electrodes and solid electrolytes. While external pressure improves contact and ionic conductivity, excessive pressure induces cracking and mechanical degradation. This review discusses the interplay of mechanical factors in sulfide, oxide, and polymer electrolytes, as well as lithium metal and alloy anodes and layered oxide cathodes. We assess the material-specific pressure requirements and their impact on structural integrity and electrochemical performance. Strategies for optimizing fabrication and operational pressure are discussed to enable robust, scalable ASSB designs.