Sulfide‐Based Electrolytes for All‐Solid‐State Sodium Batteries

ABSTRACT All‐solid‐state sodium batteries with abundant resources, low cost, high safety, and high energy density show promising potential for grid‐scale energy storage and electric vehicles, positioning them as strong candidates for the post‐lithium era. Among them, sulfide‐based solid electrolytes stand out due to the high room‐temperature ionic conductivity, comparable to that of liquid electrolytes, as well as their superior interfacial compatibility and ease of production, making them a rapidly growing focus of cutting‐edge research. Nevertheless, critical challenges persist in current sulfide‐based solid electrolytes research, including inadequate ionic conductivity, moisture sensitivity, and interfacial incompatibility, which deteriorate electrochemical performance and hinder practical implementation. Herein, a systematic overview of the structure, properties, and synthesis methods of several representative sulfide‐based solid electrolytes is provided. Next, the key challenges and current optimization strategies are comprehensively summarized. Additionally, the assembly and battery performance of sulfide‐based solid electrolytes in sodium systems, along with the long‐overlooked safety risks and technical bottlenecks for industrial production, are discussed. Finally, a summary and recommendations for the identified and potential challenges of sulfide‐based solid electrolytes for future research are proposed.