Synthesis and Performance of LiFePO_4/C Prepared by Nonaqueous Sol-Gel Method

LiFePO_4/C was synthesized by a sol-gel method using glycol as solvent.X-ray diffraction and scanning electron microscope were used for the phase identification and the structural observation of the synthesized LiFePO_4 products.The electrochemical properties including the cycle stability,the discharge capacity under different discharge rates of LiFePO_4 synthesized at 600-750℃were investigated by means of electrochemical impedance spectroscope and other methods.The results show that the crystallization and electrochemical performance of LiFePO_4/C are affected remarkably by the sintering temperature.LiFePO_4/C sintered at 700℃is well crystallized and has an even distribution of gain with size of around 150nm,exhibiting excellent electrochemical properties.Its discharge capacity reaches 150mAh/g at 0.5C and the discharge capacity still reaches 141mAh/g at 1C.The discharge capacity of the LiFePO_4/C is almost reserved after 200 cycles.