Clay‐Enabled (quasi) Solid‐State Electrolytes for Metal Batteries: Toward Safe, Sustainable, and High‐Energy Storage

Abstract (Quasi) solid‐state electrolytes (QSSEs) are a promising route to commercially viable batteries, offering superior interfacial compatibility and tunability. Yet their application is limited by low ionic conductivity, poor thermal stability, and safety risks from lithium dendrites. Clay minerals have recently emerged as attractive QSSE components owing to their unique nanostructures, abundant ion‐conducting sites, intrinsic flame retardancy, and low cost. This review summarizes the key properties of representative clays and advances in their use for QSSEs in metal (Li, Zn, Na) batteries, with emphasis on their role in ion‐transport regulation and the multi‐component interactions within clay composite solid‐state electrolytes (CCSEs). Finally, design strategies and research directions are outlined to realize high‐performance, intrinsically safe CCSEs. This review aims to deepen mechanistic understanding and accelerate the development of clay‐based electrolytes for next‐generation energy storage.