Contact Mechanics of Solid-State Batteries

The performance and stability of all-solid-state batteries (ASSBs) are critically dependent on the mechanical contact at their solid-solid interfaces. Poor contact between electrodes and the solid electrolyte results in a limited real area available for charge transfer, leading to increased interfacial impedance and performance degradation during cycling. This perspective reviews the fundamental principles of contact mechanics and their application to the dynamic, evolving interfaces unique to ASSBs. We summarize recent advances in modeling and characterization techniques that diagnose contact loss and its evolution, which often manifests as a distinct constriction resistance in impedance measurements. Finally, we identify key knowledge gaps and outline future research directions required to overcome these interfacial challenges and advance ASSB development.