Preparation and properties of LiFePO_4/C composites

LiFePO4/C was synthesized using solid-state reaction under N2 atmosphere where the reaction precursor was prepared by sol-gel method.XRD analysis proved that the sintering temperature and carbon source play an important role in crystalline of LiFePO4/C.In range of 650～700 ℃,LiFePO4 was crystallized well.When the content of carbon source was beyond 20%,the diffraction intensity was weakened.The particles of LiFePO4/C were homogeneous,about 100 nm sizes.Charge-discharge test was made with LiFePO4/C as cathode material.It was found that carbon sources had close relation to composite's initial discharge capacity.At 0.1 C rate,the initial discharge capacity was corresponding 120,135,162 mA·h/g with acetylene black,sucrose,and glucose as carbon sources.The LiFePO4/C with glucose as carbon source exhibited large current charge-discharge properties.At 1 C and 3 C rate,the initial discharge capacity was 90%,80% in 0.1 C,respectively.