Influence of sintering temperature on the electrochemical properties of P2-type Na0.67Mn0.7Ni0.2Mg0.1O2 cathodes for sodium-ion batteries

Sodium-ion batteries are thought to be ideal alternatives to Lithium-ion batteries due to their similar electrochemical properties. However, several technique obstacles in cathode materials still impede the commercialized adoption of Sodium-ion batteries. Herein, the Mg-doping P2-type Na0.67Mn0.7Ni0.2Mg0.1O2 cathode materials were synthesized via a two-step process, including sol-gels and solid-state reaction method. This paper pays much attention to the optimal calcination temperature in the synthesis procedure and its effects are subsequently investigated. According to the results, under a series of calcination temperatures from 800 to 950 ​°C, Na0.67Mn0.7Ni0.2Mg0.1O2 cathode materials shows different particle sizes and crystalline structures, exhibiting varied electrochemical properties. Among them, samples calcinated at 900 ​°C display a high specific discharge capacity of 120.9 ​mAh g−1, and a stable cycling performance of 67.2% retention at 1 C rate for 100 cycles. The results suggest that calcination temperature at approximately 900 ​°C could effectively promote the electrochemical performance, which provides a good reference for the synthesis of cathode materials in sodium-ion batteries.