锂离子电池正极材料LiFePO_4电化学性能

Electrochemical Performance of Cathode Material LiFePO_4 of Lithium Ion Batteries

分别采用蔗糖和乙炔黑作为碳添加剂,高温固相法合成LiFePO_4复合物,利用X射线衍射、扫描电子显微镜和充放电等测试技术对其晶体结构、表观形貌和电化学性能进行了研究。结果表明,合成的LiFePO_4均为单一的橄榄石型晶体结构。采用蔗糖包覆的LiFePO_4具有更好的电化学性能,以0．2 C充放电,首次放电比容量为148．6 mA·h/g,20次循环后放电容量仍为140．3 mA·h/g。

LiFePO4 composites obtained with sucrose or acetylene black coating processing were prepared via high temperature solid-state reaction. The crystalline structures, morphologies of the particles, and electrochemical performance of the samples were investigated by X-ray diffraction, scanning electron microscopy, and charge-discharge test. The results show that LiFePO4 composites were simple olive-type phase. Electrochemical tests showed that LiFePO4 composites obtained with sucrose coating processing possessed excellent electrochemical performance, the first specific discharge capacity of which was 148.6 mA · h/g during charge and discharge at 0. 2C, and even after 20 times cycling, the discharge capacity was 140. 3 mA · h/g.