Advances in All-Solid-State Batteries Based on Chloride Solid Electrolytes

Driven by the imperative for enhanced battery safety, solid electrolytes have emerged as a leading strategy in next-generation energy storage technologies. Beyond conventional polymer, oxide, and sulfide systems, chloride-based inorganic solid electrolytes have recently garnered significant attention due to their unique combination of high ionic conductivity, favorable electrochemical stability, and processability. This work presents a comprehensive review of chloride solid electrolytes, examining their crystal structures, synthesis approaches, ionic transport mechanisms, and physicochemical stability under operational conditions. Furthermore, we discuss critical considerations for integrating these materials into practical all-solid-state batteries (ASSBs), including performance across wide temperature ranges, scalable cell fabrication methods, and cost-effectiveness. By bridging fundamental material properties with device-level engineering challenges, this review aims to provide a roadmap for future research and development, highlighting the substantial promise of chloride electrolytes in enabling safe, high-performance solid-state batteries.