Effect of F-doping on the properties of LiFePO4-x/3F x /C cathode materials via wet mechanical agitation-assisted high-temperature ball milling method

LiFePO4-x/3F (x) /C (x = 0, 0.03, 0.06, 0.09) were obtained via wet mechanical agitation-assisted high-temperature ball milling method. XRD, SEM, TEM, galvanostatic testing, EIS, and CV were applied to study the effects of the amount of F-doping on the structure and electrochemical performance of LiFePO4/C. The results showed that LiFePO3.98F0.06/C displayed the best electrochemical performance: its initial discharge capacities were 162.6 (0.1 C), 156.6 (0.5 C), 150.2 (1.0 C), 144.5 (2.0 C), 131.6 (5.0 C), and 115.8 mAhg(-1) (10 C), respectively. Moreover, its discharge capacity was 110.5 mAhg(-1) over 100 cycles with a capacity retention rate of 95.4% at 10 C-rate. F-doping is suggested to be an effective approach to enhance the electrochemical performance of LiFePO4.