Recent Progress and Advances of High-entropy Polyanionic Cathodes in Lithium-ion and Sodium-ion batteries

In recent years, research on lithium-ion and sodium-ion battery cathodes has advanced rapidly, with materials categorized into layered oxides, polyanionics, and Prussian blue analogues. Polyanionic cathodes stand out for sodium-ion batteries due to their structural stability, safety, and long cycle life, but face challenges in phase transition and property optimization. High-entropy doping has emerged as a key strategy to enhance their electrochemical performance. This review first introduces the concept of high entropy and its stabilizing role in polyanionics, and then outlines structural and electrochemical improvements via high-entropy doping, such as enhanced ion/electron transport and phase stability. Finally, the characteristics of high-entropy polyanionic cathodes for lithium-ion and sodium-ion batteries were summarized. In addition, we describe the challenges encountered in this research area as well as potential future directions for the implementation of high-entropy strategies in the field of polyanionic cathode materials.