Research on the construction of high-stability O3-type sodium-ion battery cathode materials via B-Co doping based on solid solutions

Abstract

The O3-type Na[Ni_1/3Fe_1/3Mn_1/3]O₂ cathode material for sodium-ion batteries is restricted by problems such as poor performance and low capacity retention rate during high-rate charge and discharge, making it difficult to be applied on a large scale. In this study, a B-Co co-doping strategy based on solid solution was adopted to address the issues of low capacity retention rate and slow ion diffusion rate caused by the complex phase transition of the Na[Ni_1/3Fe_1/3Mn_1/3]O₂ cathode material. B-Co co-doped Na[Ni_1/3Fe_1/3Mn_1/3]O₂ samples were prepared by solid-phase sintering method and investigated. The B-Co co-doped sample exhibits an initial discharge specific capacity of 105.4 mAh·g⁻¹ at a 1C rate, with a capacity retention rate as high as 92.79 % after 100 cycles. The experimental results demonstrate that the B-Co co-doping strategy based on solid solution can effectively mitigate phase transition, increase the interlayer spacing, and significantly enhance the structural stability, endowing the cathode material with high electrical conductivity, high structural stability, and high specific capacity retention rate. This research provides solid theoretical support and important references for the development of high-performance sodium-ion battery cathode materials.