High-performance triphylite-NaFePO4 synthesized by solvothermal sodium insertion process for sodium-ion batteries

Triphylite-NaFePO4 has attracted considerable attention for utilization in sodium-ion batteries on account of its highest theoretical capacity amongst polyanionic type compounds. Herein, we propose an innovative solvothermal sodium insertion method, for the first time to synthesize triphylite-NaFePO4, wherein ethanol is employed as a reducing agent. Triphylite-NaFePO4 shows optimal electrochemical performance of 125.40, 109.53, 90.11, 70.97, and 54.63 mAh/g at 0.1, 0.2, 0.5, 1, and 2C, respectively. In addition, the capacity retention rate is 91.41 % following a total of 100 cycles at 0.1C. Therefore, this novel solvothermal sodium insertion method provides a reference pathway for the preparation of triphylite-NaFePO4.