Na–Ti Codoping to Enhance the Electrochemical Performance of Li0.98Na0.02Mn0.6Fe0.4–xTixPO4/C Cathode Materials

In order to improve the deficiencies of LMFP cathode materials, such as low specific capacity, poor cycling performance, and inadequate high-rate capability, the present experiments were conducted to prepare Na–Ti-doped LMFP/C composites by the carbothermal reduction method, and the Li0.98Na0.02Mn0.6Fe0.4–xTixPO4/C (x = 0, 0.01, 0.02, 0.03) composites samples were successfully produced. The experimental results indicated that appropriate Na+ doping optimizes the crystal structure of the material but increases the energy band gap, rather than diminishing the electrochemical properties such as cell multiplicity performance and specific capacity. Conversely, the addition of Ti enhances the lattice length, enlarges the cell volume, and introduces impurity bands, which significantly improves electronic conductivity. The codoping of two elements mitigated the Jahn–Teller effect and reduced lattice distortion, thereby enhancing the performance of the cell in terms of capacity and high-rate capability. Even after 100 cycles at a high rate of 5 C, the battery specific capacity can still reach 132.9 mA h g–1. This demonstrates that two-element cation doping is an effective method for improving the electrochemical performance of LMFP materials.