Critical Assembly and Test Procedures Driven by Mechanical Constriction Principle for Advanced Performances of Solid‐State Batteries

The perspective aims to articulate the fundamental aspect of the unique mechanical constriction effect that is implied in some widely used experimental procedures in solid‐state battery assembly and test. The effect is important to battery performances in terms of the voltage stability with high voltage cathodes and Li metal anode, the fast‐charging ability using Li metal anode, and the cycling stability. The physical picture of the mechanical constriction effect under the constrained ensemble is first described. Theoretical and computational approaches to implement such a physical picture are then introduced to make concrete metastability and kinetic stability predictions that can be compared with experiments from various measurable aspects. Future directions are discussed in the end regarding a synergistic mechanical constriction design by simultaneously considering battery materials, assembly procedures, and device designs for advanced battery performances and the compatibility with practical considerations of interest to industries. It can be envisioned that fully unlocking the potential of the mechanical constriction design principle will greatly speed up the development of solid‐state batteries.