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. The designed Mg-doping P2-type Na0.67Mn0.7Ni0.2Mg0.1O2 cathode materials have been fabricated via a facile controllable method. Notably, this paper pays much attention to the optimal calcination temperature in the synthesis procedure and its effects are subsequently investigated. Pure P2 cathode materials were synthesized at high temperature above 900 ​°C, while P2/P3 biphasic materials were produced at low temperatures from 800 to 850 ​°C. 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. [Display omitted] •Mg-doping P2-type Na0.67Mn0.7Ni0.2Mg0.1O2 cathode materials are successfully synthesized through a two-step process.•The effects of sintering temperature on electrochemical performance in P2-type Na0.67Mn0.7Ni0.2Mg0.1O2 cathodes.•A two-phase structure consisted of P2 and P3-type structure is synthesized at a relatively low calcination temperature.•The pure P2-type Na0.67Mn0.7Ni0.2Mg0.1O2 cathodes demonstrates superior performance for sodium storage.