碳包覆Li_3VO_4作为锂离子电池负极材料的研究

Study of Carbon-Encapsulated Li_3VO_4 as Anode for Li-ion Batteries

采用溶胶-凝胶法合成碳包覆Li3VO4复合材料(Li3VO4/C),通过X-射线衍射仪(XRD)、扫描电子显微镜(SEM)、热重分析仪(TG)对其进行了表征,探究了该材料作为锂离子电池负极材料的电化学性能。结果表明,该材料具有良好的循环性能和优异的倍率性能。在1.25 C(1 C=400 m Ah/g)的电流密度下,其首次充电比容量为199.6 m Ah/g,循环150次后,其容量保持率为89.2%。此外,在充放电倍率分别为0.5、1、2、5、10 C时,其充电比容量分别为228.7、202、180.5、149.9、116.6 m Ah/g。

The carbon-encapsulated Li3VO4 sample(Li3VO4/C)was prepared by a simple sol-gel method.The chemical composition and morphology of the Li3VO4/C was investigated by X-ray diffraction(XRD),thermogravimetric analysis(TG)and scanning electron microscopy(SEM).The electrochemical performance of Li3VO4/C as anode material for Li-ion batteries was studied.The results showed that Li3VO4/C presented good cycling stability and exceeding rate performance.The Li3VO4/C exhibited an initial charge capacity of 199.6 mAh/g(charge capacity)at the charge-discharge rate of 1.25 C(1 C=400 mAh/g),maintaining capacity retention of 89.2%within 150 cycles.Furthermore the charge capacity of the sample can retain 228.7、202、180.5、149.9 and 116.6 mAh/g at 0.5、1、2、5 and 10 C respectively.