锂离子电池正极材料Li(Mn_xFe_(1-x))PO_4的合成及电化学性能的研究  

Synthesis of Li(Mn_xFe_(1-x))PO_4 and study on its electrochemical performances

作　　者：宋士涛[1] 邓小川[1] 孙建之[1] 马培华[1] 魏述彬[1] 闫春艳[1] 

机构地区：[1]中国科学院青海盐湖研究所

出　　处：《功能材料》2005年第12期1941-1943,共3页Journal of Functional Materials

基　　金：国家科技攻关计划课题资助项目(2001BA602B-01)

摘　　要：采用高温固相法合成了组成为Li(MnxFe1-x)PO4(x=0、0.2、0.4、0.6、0.8、1.0)的锂离子电池正极材料。通过对合成样品的XRD、SEM及电化学性能(循环性能,大电流放电性能)的研究表明,少量Mn的掺杂未影响到LiFePO4的晶体结构,但显著改善了它的电化学性能。Li(Mn0.2Fe0.8)PO4与LiFePO4材料相比有更好的电化学性能,在低放电倍率(电流密度为20mA/g)时,放电容量为150mAh/g,当放电倍率提高到2C时,放电容量仍可达113mAh/g,且循环性能良好。Composites Li（MnxFe1-x）PO4 （x=0,0. 2,0. 4,0. 6,0. 8,1. 0） were synthesized by high temperature solid state reaction method. The samples were characterized by X-ray diffraction and scanning electron microscope,and they were investigated including cycling behavior and large current discharging. The results indicate that the Mn^2＋ ion dopant does not affect the structure of LiFePO4 but considerable improves its kinetics in terms of capacity delivery and cycle performance. The LiMn0.2 Fe0.8 PO4 showed better electrochemical performances than LiFePO4. At a low discharging rate,LiMn0.2 Fe0.8 PO4 is capable of delivering reversible specific capacity of 150mAh/g,with fairly stable cycleability. Even at a 2C discharging rate,it can show capacity of 113mAh/g,too.

关 键 词：磷酸铁锂 正极材料 离子掺杂 电化学性能 

分 类 号：TQ912.9[化学工程]