碳掺杂方式对磷酸铁锂电化学性能的影响

为了提高LiFePO4的电化学性能,分别采用在原料中添加导电炭黑(途径A)和对反应前驱体用环氧树脂进行包覆(途径B)的途径,通过高温固相反应合成了LiFePO4/C锂离子蓄电池复合正极材料,并用X-射线衍射、扫描电镜和恒电流充放电测试等方法对其晶体结构、表观形貌和电化学性能进行了研究。研究结果表明:所合成LiFePO4/C试样均为单一的橄榄石型晶体结构;通过途径B合成的LiFePO4/C材料,其炭黑分布更均匀,电性能更佳,以0.1C、1.0C以及2.0C倍率放电,该材料首次放电比容量分别为156.4mAh/g、145.7mAh/g和128.9mAh/g。

Influence of carbon doping method on the electrochemical performances of lithium iron phosphate

To improve the electrochemical performances, LiFePO4/C composite cathode materials were synthesized through adding carbon black (method A) and coating with epoxy resin (method B) by high temperature solid-state reaction. The crystalline structure, crystalline size, morphology of particles and charge-discharge performances of the samples were investigated by X-ray diffraction,scanning electron microscopy and galvanostatic charging- discharging experiments. The results showed that the LiFePO4/C samples were pure olive-type structure. The composite synthesized by the method B showed even carbon distribution and better electrochemical performances, whose first specific discharge capacities were 156.4 mAh/g, 145.7 mAh/g and 128.9 mAh/g at the rate of 0.1 C, 1.0 C and 2.0 C respectively.