The novel P3-type layered Na0.65Mn0.75Ni0.25O2 oxides doped by non-metallic elements for high performance sodium-ion batteries

Due to the attractive advantage of safety and cost of sodium-ion batteries, lithium-ion batteries can be replaced by sodium-ion batteries with the ever-increasing demand of large-scale energy storage systems. However, short cycle life and poor rate performance restrict sodium-ion batteries further commercial application. Cathode materials are one of the most important components of sodium-ion batteries, which have an unparalleled effect on the electrochemical performance of sodium-ion batteries. Herein, the novel P3-Na0.65Mn0.75Ni0.25O2 cathode material doped by non-metal elements is synthesized via hydrothermal method and subsequent low temperature annealing process. The as-prepared P3-Na0.65Mn0.75Ni0.25O2 shows excellent electrochemical performance due to doping of non-metal elements. It can be found that fluorine doped Na0.65Mn0.75Ni0.25F0.1O1.9 can distinctly suppress P3-O1 phase transition and deliver a higher reversible capacity of 163.7 mAh g−1 at 0.1 C, while boron doped Na0.65Mn0.75Ni0.25B0.1O2 transforms from P3 phase to a more stable P2 phase and exhibits remarkable cycle life and rate performance. Therefore, this new strategy doping by means of non-metal elements provides a significant exploration for the development of the high capacity electrode materials of sodium-ion batteries.