Prilling and Coating Strategy to Synthesize High-Performance Spherical NaNi_0.4Fe_0.2Mn_0.4O₂ Cathode Materials for Sodium Ion Batteries

Low-cost sodium ion batteries are of great significance in large-scale energy storage applications. With its high energy density and simple synthesis process, layered transition-metal oxides have become one of the most likely sodium ion battery cathode materials to replace lithium ion batteries in the energy storage market. Here, we report a prilling and MoS₂ coating strategy to prepare the spherical cathode material. The spherical micronano particles shorten the diffusion path of Na⁺, restrain the complexity phase transitions, and enhance the tap density of the materials. In addition, the MoS₂ coating improves the electrical conductivity of the material and the structural stability of the cathode material in air. The initial specific discharge capacity is 148.4 mA h g^-1 at 0.1 C, which can be maintained at 128.9 mA h g^-1 after exposure to air for 10 days. This method dramatically improves the energy density and structural stability of the cathode material, which provides a new scheme for preparing high-performance sodium ion batteries.