掺杂对LiMn_2O_4正极材料的结构和性能的影响

Doping effect of cobalt,cerium and magnesium to spinel LiMn2O4 on their structures character and properties

采用溶胶凝胶法合成了尖晶石型LiMn2O4正极材料,选取钴、铈和镁作为掺杂元素,考察了钴、铈和镁的掺杂对LiMn2O4正极材料的结构和电化学性能的影响.并运用XRDI、R、BET等方法对所合成的材料进行了表征.实验结果表明,掺杂一定量钴、铈和镁后的LiMn2O4正极材料循环寿命优于未经掺杂的LiMn2O4正极材料,循环50次后,3种掺杂后所得的电池材料的容量保持率均达95%以上.其中以掺杂钴的LiCo0.2Mn1.8O4正极材料循环性能最好,首次充放电容量达到105.6 mAh/g,50次循环后,其充放电容量仍保持在100.8 mAh/g.

The positive materials of spinel LiMn2O4 were prepared by sol-gel method. The performance of a low cost, good rechargeable battery technology based on the LiM0.2 Mnl.8O4 （M = Co, Ce, Mg） was described and compared to LiMn2O4 positive materials. The doping effect of Co,Ce, Mg into LiMn2O4 positive materials was studied and the charge-discharge was carried to test the typical property of the new materials of LiM0.2 Mnl. 8O4 （M= Co, Ce, Mg）. The structure characters were measured by XRD, IR, and BET techniques. The results revealed that Mdoped （M=Co,Ce,Mg） species could stabilize the structure of LiMn2O4 spinel and decrease the dissolution of manganese in the electrolyte effectively. The presence of Co,Ce, Mg in LiMn2O4 positive materials results in the improvement of the cyclization stability.