流变相法合成高倍率性能优异的LiFePO_4/C复合材料

Synthesis of LiFePO_4/C composite with excellent high-rate performance by rheological phase method

以月桂酸为碳源和表面活性剂,采用流变相法合成性能优异的LiFePO4/C复合材料。研究了不同制备方法对材料结构、形貌和电化学性能的影响。采用XRD、SEM、电化学循环性能测试以及循环伏安测试对材料进行表征。结果表明:相比固相法,流变相法合成的材料粒径更小,仅有200 nm,且分布均匀;0.1 C下材料的放电比容量可达155mAh/g,10 C放电比容量高达115 mAh/g,且经820次循环后容量保持率高达95%,再经20 C放电,比容量仍有101mAh/g,具有优异的高倍率循环性能。

LiFePO4/C composite material was synthesized by rheological phase method using lauric acid as carbon source and surfactant.The effects of different methods on structure,morphology and electrochemical performance of material were researched.The materials were characterized by XRD,SEM,electrochemical test and cyclic voltammetry.The results show that compared with solid state method,the material prepared by rheological phase method has smaller particle of 200 nm and uniform distribution;the discharge specific capacity is up to 155 mAh/g at 0.1 C,115 mAh/g at 10 C,and the retention rate of capacity is above 95% after 820 cycles,even at the high current density of 20 C,the material still presents a discharge specific capacity of 101 mAh/g.The sample has an excellent cycling performance at high rate.