一种商品化锂锰氧化物的物理化学特性

Physical and chemical performances of a commercial lithium manganese oxide used in Li-ion battery

使用ICP、SEM、XRD、CV和EIS等方法 ,研究一种商品化的锂离子电池用锂锰氧化物的一些物理化学性能。结果表明 :这种锂锰氧化物主要含有锂、锰外 ,还含少量铝 ;其晶体结构属于尖晶石型 ,晶胞常数a =0 82 2 6nm ,比标准锂锰氧化物 (LiMn2 O4 ,a =0 82 48nm)小 ;该氧化物为球形颗粒 ,平均粒径为 5 0 μm ;模拟电池正极的初始放电容量为14 1mAh/g ,接近理论值 ( 14 8mAh/ g) ,但其容量下降较快 ,2 0次循环后容量下降 5 1% ;随着循环次数的增加 ,锂离子在正极混合物中的扩散系数愈来愈小。

Some physical and chemical performances of a commercial lithium manganese oxide used in Li ion batteries were studied by using several techniques including ICP?SEM?XRD?CV and EIS Besides the matrix elements lithium and manganese, the oxide contained a little aluminum It was a spinel structure with a =0 822?6nm, less than the standard of spinel LiMn 2O 4 ( a =0 824?8nm) Its grain was spherical with an average diameter of 50 μm Its first discharge capacity in a model battery was 141mAh/g, close to the theoretical capacity of LiMn 2O 4(148 mAh/g ), but its capacity decreased by 51% after 20 cycles The diffusion coefficient of Li ions in the positive mixture decreased with increasing cycle