Development of Sodium-Lithium-Manganese-Cobalt Oxide with B Doping or B/F Dual Doping as Cathode Electrode Materials for Sodium-Ion Batteries.

The abundance of raw materials is a significant advantage that positions sodium-ion batteries (SIBs) as a promising energy storage solution for the future. However, the low cycle efficiency and poor rate capacity of cathode materials have hindered the commercialization of SIBs, prompting extensive research efforts to address these challenges. Ion doping into the material structure is considered to be an effective, simple, and scalable approach to enhancing the electrical performance of cathode materials. In this work, B and F elemental ions were selectively doped into the structure of sodium-lithium-manganese-cobalt oxide material via the sol-gel method combined with calcination. The effects of B and F ion doping on the properties of the obtained materials exhibited distinct variations, particularly in the electrochemical performance. While the B-doped material (B-NLMC) exhibited a specific capacity of up to 166.5 mAh g^-1 at a current density of 10 mA g^-1 and maintained 72.1% capacity after 100 cycles, the material simultaneously doped with B and F ions (BF-NLMC) demonstrated lower specific capacity and cycling efficiency compared to B-NLMC. However, the BF-NLMC material exhibited significantly improved rate capability, delivering a specific capacity of up to approximately 80 mAh g^-1 at a high current density of 200 mA g^-1. Obviously, this research offers valuable insights into diversifying doping strategies to enhance the electrochemical performance of cathode materials, contributing to the advancement of SIB technology.