锂离子电池正极材料LiNi_(0.5)Mn_(1.5)O_4的制备及性能研究

Synthesis and electrochemical properties of LiNi_(0.5)Mn_(1.5)O_4 cathode materials for lithium-ion batteries

以Li(CH3COO).2H2O、Ni(CH3COO)2.4H2O、Mn(CH3COO)2.4H2O和H2C2O4.2H2O为原料,聚乙二醇20000为分散剂,采用化学合成法制备了具有立方尖晶石结构的锂离子电池正极材料LiNi0.5Mn1.5O4。通过XRD、SEM和充放电测试对样品进行表征。850℃下焙烧制备的LiNi0.5Mn1.5O4样品电化学性能最佳,在3.5～4.9V电压范围内以0.2、0.5、1、2和5C充放电,其首次放电比容量分别为132.9、117.3、111.2、104.8和91mAh/g,20次循环后容量保持率分别为93.2%、98.9%、97.4%、97.3%和95.5%。

The lithium-ion battery cathode material LiNi0.5Mn1.5O4 with cubic spinel structure were synthesized by a chemical route using Li（CH3COO）.2H2O,Ni（CH3COO）2.4H2O,Mn（CH3COO）2.4H2O and H2C2O4.2H2O as raw materials,and polyethylene glycol 20000as dispersant.The evaluation of the synthesized samples were carried out by using X-ray diffraction,scanning electron microscopy and charge-discharge tests.When calcinated at 850℃,the LiNi0.5Mn1.5O4samples show the best electrochemical performance.The specific discharge capacities were 132.9,117.3,111.2,104.8and 91mAh/g at 0.2,0.5,1,2,5C（1C=146.7mAh/g）rates in the range of 3.5-4.9V,and after 20cycles the capacity retention are 93.2%,98.9%,97.4%,97.3%,95.5%,respectively.