Inorganic All‐Solid‐State Sodium Batteries: Electrolyte Designing and Interface Engineering

Inorganic all‐solid‐state sodium batteries (IASSSBs) are emerged as promising candidates to replace commercial lithium‐ion batteries in large‐scale energy storage systems due to their potential advantages, such as abundant raw materials, robust safety, low price, high‐energy density, favorable reliability and stability. Inorganic sodium solid electrolytes (ISSEs) are an indispensable component of IASSSBs, gaining significant attention. Herein, this review begins by discussing the fundamentals of ISSEs, including their ionic conductivity, mechanical property, chemical and electrochemical stabilities. It then presents the crystal structures of advanced ISSEs (e.g., β/β''‐alumina, NASICON, sulfides, complex hydride and halide electrolytes) and the related issues, along with corresponding modification strategies. The review also outlines effective approaches for forming intimate interfaces between ISSEs and working electrodes. Finally, current challenges and critical perspectives for the potential developments and possible directions to improve interfacial contacts for future practical applications of ISSEs are highlighted. This comprehensive review aims to advance the understanding and development of next‐generation rechargeable IASSSBs. This review summarizes various inorganic solid‐state electrolytes (such as oxide‐based, NASICON‐type, sulfide‐based, etc.) for all‐solid‐state sodium batteries. Their crystal structures, and modification strategies to enhance ionic conductivity are discussed. Additionally, methods for modifying the interfaces between solid electrolytes and cathodes/anodes, and optimizing full battery performance are explored. Lastly, the future development directions of all‐solid‐state sodium batteries are proposed.