Optimized electrochemical performance of LiMn0.9Fe0.1−xMgxPO4/C for lithium ion batteries
Optimized electrochemical performance of LiMn0.9Fe0.1−xMgxPO4/C for lithium ion batteries
复制标题
DOI：
10.1016/j.electacta.2011.01.121
复制
发表时间：
2011-04
影响因子：
6.6
通讯作者：
H. Yi;Chen Hu;H. Fang;Bin Yang;Yaochun Yao;Wenhui Ma;Yong-nian Dai
中科院分区：
文献类型：
--
作者：
H. Yi;Chen Hu;H. Fang;Bin Yang;Yaochun Yao;Wenhui Ma;Yong-nian Dai
采用固相反应法合成了一系列LiMn0.9Fe0.1− xMgxPO 4/C（x=0，0.01，0.02，0.05）材料，并通过X射线衍射、扫描电镜、拉曼光谱和电化学测试研究了合成温度和Fe/Mg比对材料电化学性能的影响。在650 ~ 800°C范围内，随着合成温度的升高，Fe和Mg共取代LiMnPO 4的电化学性能明显提高，但进一步升高会导致杂质的形成，导致容量急剧下降。Fe和Mg共掺杂能显著提高LiMnPO 4的电化学活性，但Mg掺杂量过高会降低LiMnPO 4的倍率性能。在800°C下合成的LiMn0.9Fe0.09Mg0.01PO4/C表现出最佳的电化学性能，具有高容量和优异的倍率性能。即使以10 C的速率放电，仍然观察到60 mAhg − 1的容量。
A series of LiMn0.9Fe0.1−xMgxPO4/C (x=0, 0.01, 0.02, 0.05) was synthesized by a solid state reaction, and the effect of synthesis temperature and Fe/Mg ratio on the electrochemical performance of the obtained materials was investigated by X-ray diffraction, scanning electron microscopy, Raman spectroscopy and electrochemical measurements. The electrochemical performance of the Fe and Mg co-substituted LiMnPO4was obviously improved with increasing synthesis temperature from 650 to 800°C, but further increase led to an abrupt capacity loss due to the impurity formation. The Fe and Mg co-substitution could remarkably enhance the electrochemical activity of LiMnPO4compared with the Fe substitution only, but too high level of Mg doping would worsen the rate capability. The LiMn0.9Fe0.09Mg0.01PO4/C synthesized at 800°C demonstrated the optimum electrochemical performance with a high capacity and an excellent rate capability. Even discharged at the rate of 10C, a capacity of 60mAhg−1was still observed.