Various amounts of ethylene glycol (EG) were used during the preparation of LiFePO4/C composite by hydrothermal method. The effects of EG on the structure, morphology, and the electrochemical performance of LiFePO4/C were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, surface area measurement, and electrochemical testing methods. The results showed that the ratio of the EG/water of the reaction medium for the electrode preparation has significant effects on the morphology and the crystallinity of the particles. The results also showed that the LiFePO4/C prepared with the optimized EG/water ratio (7/93) exhibited the best electrochemical performance. In particular, this electrode exhibited the best specific discharge capacity of 168.8 mAh g−1 at 0.1 C rate because of its uniform particle distribution, its large specific surface area, and its best crystallinity which is favorable for high Li-ion diffusion during redox reaction.
