Chloride-Based Solid Electrolytes from Crystal Structure to Electrochemical Performance

To address the challenges of liquid-state batteries, all-solid-state lithium-ion batteries (ASSLBs) have gained increasing attention due to their high safety and energy density. A critical aspect of this development is the creation of suitable solid electrolytes. Among these, chloride-based solid electrolytes have emerged as promising candidates due to their high ionic conductivity and wide electrochemical stability window. Compared with earlier halide materials, halide solid electrolytes have made significant breakthroughs; however, several challenges remain. This Perspective comprehensively summarizes the latest advancements and current challenges in halide solid electrolytes, with a particular focus on the relationship between crystal structure, conduction mechanisms, and doping structures. Additionally, we reveal the challenges at the electrode–electrolyte interfaces and explore strategies to enhance the interface stability. Finally, we provide an overview of approaches to designing high-performance halide solid electrolytes, offering insights and directions for the future development of all-solid-state lithium-ion batteries.