Evolution mechanism and response strategy of interface mechanics in all solid-state lithium metal batteries

All-solid-state lithium metal batteries (SSBs) are considered one of the most promising next-generation batteries due to its high energy density and safety, which can be popularized and applied in the electronic information, transportation, and power grids fields in the future. However, the critical bottleneck is the interface instability. For one thing, establishing effective solid-solid interface contact is crucial to enhancing the performance of SSBs, with the distribution of stress playing a significant role. For another, electrochemical processes induce mechanical strain at the electrode/SE interface, leading to dendrite growth. Therefore, aiming at this failure, this review conducts a comprehensive analysis of the mechanical evolution mechanism of internal interfaces in SSBs, together with potential methods for controlling performance. It introduces the transport mechanism of ions in solid electrolytes (SEs), the change mechanism of the stress field based on damage mechanics and fracture mechanics. Then a classification of the SEs is provided, and interface mechanical behavior and characterization technologies are discussed. This information can guide efforts to inhibit the formation of lithium dendrites and regulate the interfacial stability of SEI. Finally, it explores the future development and research focus of SSBs, aiming to present new potential for developing stable and high-performance batteries.