Reaction mechanism and electrochemical performance of LiFePO4/C cathode materials synthesized by carbothermal method

Abstract Spray drying and carbothermal method was employed to investigate reaction mechanism and electrochemical performance of LiFePO 4 /C cathode by using different carbon sources. Micro-structural variations of LiFePO 4 /C precursors using different carbon sources were studied by Thermo-gravimetric (TG)/Differential Thermal Analysis (DTA). The LiFePO 4 /C samples were characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) absorption spectroscopy. The results indicated that the crystallization temperature of LiFePO 4 was 453 °C, while the transform temperature was 539 °C from Li 3 Fe 2 (PO 4 ) 3 to LiFePO 4 . At 840 °C, LiFePO 4 /C sample with an excess of impurity phase Fe 2 P gave much poorer electrochemical performance. The severe decomposition of LiFePO 4 /C happened at 938 °C and generated impurity phases Li 4 P 2 O 7 and Fe 2 P. The clear discharge platform of Fe 2 P emerged at around 2.2 V.