尖晶石型LiMn_2O_4高温电性能的研究

The Effect of Lithium Resource and Manganese Resource on the Performance of LiMn_2O_4 at Elevated Temperature

采用熔盐浸渍法用不同的锂锰源(LiNO_3、LiOH·H_2O、EMD、CMD)制备了4种尖晶石型LiMn_2O_4正极材料。对材料进行了XRD结构表征,采用最小二乘法计算了样品的晶格常数。采用BET法测定了各样品的比表面积,测定了各样品的电导率。检测了各样品在高温下的贮藏和循环性能,在高温下作了循环伏安分析。结果表明虽然各样品均属于立方尖晶石结构但晶格常数和比表面积均不相同。以LiOH·H_2O和EMD为原料制得的样品的极化最小,在高温下的循环性能最好。

Four LiMn2O4 cathodes were prepared by melt-impregnation method with different La sources and Mn sources (LiNO3, LiOH-H2O, EMD, CMD). The structure of the materials was characterized by XRD and the lattice parameters of the samples were calculated by using least square method. The specific surface area was determined by BET method and the electrical conductivity of the samples was also determined. The electrochemical performance of the cathodes at room temperature and elevated temperature was tested. And cyclic voltammetric study was performed for all the samples. The results showed that although the structure of the samples was confirmed to be cubic spinel structure, the lattice parameter and specific surface area of the samples are different. The cell polarization of the cathode developed by LiOH -H2O and EMD was identified to be the least and the elevated temperature cyclability to be the best.