Fabrication of Composite Cathode for All‐Solid‐State Sodium Batteries

Abstract All‐solid‐state sodium‐ion batteries (ASSSBs) are regarded as highly promising candidates for large‐scale energy storage systems owing to their expected lower cost and enhanced safety. In recent years, the advent of novel fast ion‐conducting solid electrolytes (SEs) has further accelerated the rapid development of this field. Nevertheless, several critical challenges remain, preventing the performance of ASSSBs from surpassing that of their liquid‐electrolyte counterparts. Among these, a key obstacle lies in the design of cathode systems that ensure optimal compatibility between the SE and the cathode active material (CAM). This review focuses on the essential properties and persistent challenges of CAM in ASSSBs employing inorganic SEs and highlights the current strategies developed to address these issues. Particular attention is given to the design considerations at the cathode, particle, and interface levels, including aspects related to the microstructure, mechanical integrity, and (electro)chemical interactions with the SE. Finally, the review outlines future directions and design principles for the development of next‐generation cathode materials in ASSSBs.