Preparation of LiFePO_4/C composite materials by natural carbon sources

Cathode material LiFePO4/C was synthesized with 5% lignin, ascorbic acid or cellulose as carbon sources.The crystalline structure, morphology and electrochemical performance of LiFePO4/C were investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM) and charge-discharge performance test methods. The results show that LiFePO4/C is simple pure phase olivine-type crystal structure and no obvious impurity phase. LiFePO4/C composite materials, doped with lignin as natural carbon sources, show excellent electrochemical performance with the first discharge specific capacity of 144.7 mAh/g at the rate of 0.2 C and the discharge specific capacity of 146.57mAh/g after 30 times cycling.