Structural and Electrochemical Property of LiFePO₄/C Composites Prepared by Different PEG Combination Systems

The LiFePO₄/C composites were prepared by rotary evaporation method using different molecular weights polyethylene glycol (PEG) combination systems as the template and the carbon source. The crystal structure, morphology and electrochemical performance of the samples were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and galvanostatic charge-discharge tests. The results show that the crystalline size and morphology of the LiFePO₄/C composites can be controlled by the different combination systems. The sample synthesized using PEG200+PEG35K as carbon source has spherical shape and small size with narrow size distribution. It shows the outstanding electrochemical performance with the first discharge capacities of 168.3 mA·h/g, 138.1 mA·h/g at 0.1C and 1C rate respectively.