Research Progress on Modification of Cathode Materials for Polyanionic Sodium-Ion Batteries

As one of the main anode materials for sodium-ion batteries, polyanionic anode materials for sodium-ion batteries have the advantages of long cycle life, high safety, low price and suitable for large-scale energy storage, but there are also problems such as low energy density and low conductivity. In order to optimize the energy density, conductivity, service life and other properties of polyanionic sodium ion cathode materials, doping, surface coating and structural design are needed to modify them. Reasonable modification methods have been proved to significantly improve the properties of materials. In this paper, phosphate, sulfate and other types of polyanionic sodium-ion batteries are first introduced, then the latest research results of element doping, surface coating and structural design are reviewed, and the existing research results are evaluated. Finally, the modification methods of the positive electrode materials of polyanionic sodium-ion batteries are prospected, which provides important research ideas for the commercial application of sodium-ion batteries in the future.