Effect of Sintering-method on Electrochemical Performance of LiFePO_4/C Cathode Material

Static nitrogen atmospheres(SA),dynamic nitrogen atmosphere(DA) and static vacuum(SV) sintering methods were adopted to synthesize LiFePO4/C cathode material.The crystalline structure,morphology and electrochemical performances of the products were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM) and galvanostatic charge/discharge test.Effects of sintering method on crystallinity,particle size,carbon content,reaction temperature and electrochemical performance of the as-obtained LiFePO4/C cathode material are remarkable.SV-sintered LiFePO4/C has better crystalline,but DA-sintering is helpful to obtain LiFePO4/C particles with smaller particle size and narrower particle size distribution,kinetics of Li+ diffusion is also improved.For the DA-sintered sample,sintering temperature can be reduced to 500℃ with excellent electrochemical performance.Specific discharge capacity for the first cycle reaches 163.4 mAh/g at 0.5C rate,and up to 99.02% of discharge capacity can be kept after 50 cycles.