Preparation and improvement electrochemical performance of Ni-Fe doped porous LiMnPO₄/C materials

Lithium manganese phosphate (LiMnPO₄) is the most promising candidate for the next generation of lithium-ion battery cathode materials due to its 4.1 V(vs. Li/Li⁺) high voltage platform. At present, the discharge rate performance and cycle stability are still poor. And here, various Fe, Ni co-doped carbon-coated LiMnPO₄ composites materials LiMnPO₄/C were successfully prepared using coprecipitation and solvothermal methods. Morphological and electrochemical performance analyses were conducted on the LiMnPO₄/C materials prepared by different methods to explore the relationship between material morphology and electrochemical performance. Compared with the coprecipitation method, LiMnPO₄/C prepared by the solvothermal method has a smaller particle size and a more regular morphology. Moreover, after the addition of glucose as an auxiliary, the particles exhibit a spindle-shaped porous structure, leading to improved cycling performance and rate capability, and demonstrating superior electrochemical properties. At 0.1, 0.2, 0.5, 1, and 2 C, the discharge specific capacities are 121.4, 102.7, 91.2, 81.5, and 53.7 mAh g^- 1, respectively. After 100 cycles at 1 C rate, 91% of the initial capacity is still retained. The above results indicate selecting appropriate preparation methods and controlling the structure and morphology of the material, the electrochemical activity of LiMnPO₄ can be directly influenced, which providing a new approach to improve the electrochemical performance of LiMnPO₄.