由CO还原FePO4和LiOH前驱体合成LiFePO4正极材料,应用XRD、SEM表征材料结构和形貌、充放电曲线测试电化学性能.结果表明,LiOH过量5%合成的LiFePO4样品颗粒度约200 nm,包覆碳后LiFePO4电极0.1C放电容量可达158 mAh/g.高温现场XRD对该合成反应作实时监控,借助时间分辨图谱分析,检测出Li3Fe2(PO4)3中间物.动力学研究表明成核与生长是该合成过程的速控步骤,反应活化能为89.44 kJ/mol.

LiFePO4 cathode material was synthesized by CO reducing FePO4 and LiOH precursors.The structure,morphology and electrochemical performances of such LiFePO4 material were characterized by XRD,SEM and charge-discharge tests.It was shown that the particle size of the LiFePO4 synthesized with 5% excess of LiOH in the precursor was about 200 nm.By carbon coating,the LiFePO4 electrode was able to deliver a reversible capacity of 158 mAh·g-1 at 0.1C discharge rate.Temperature-programmed X-ray diffraction was employed to monitor the reaction during the formation of LiFePO4,and Li3Fe2(PO4)3 was found to be an intermediate by analyzing the time-resolved XRD patterns.Kinetic study indicates that nucleation and their growth is the rate-determining step in the process of the reaction and the activation energy of this reaction was 89.44 kJ/mol.