反应球磨合成尖晶石LiMn_2O_4及其电化学性能

Reaction Milling Synthesis and Electrochemical Performance of Spinel LiMn_2O_4

以KMnO4、MnSO4·H2O和LiOH·H2O为原料,采用反应球磨法合成了LiMn2O4。用X射线衍射仪、扫描电子显微镜对产物的结构和表面形貌进行表征。结果表明,反应球磨后生成了LiMn2O4、Li2SO4·H2O和KLiSO4,水洗后的产物为尖晶石LiMn2O4,但结晶度不高;经800℃保温30 min后LiMn2O4晶型完整,颗粒细小,粒径分布均匀,平均粒径为500 nm左右。电化学测试结果表明,LiMn2O4在0.2、0.5、1、3 C下的首次充放电比容量分别为115.8、107.0、105.5、98.2 mA.h/g。材料循环性能良好,10次循环后容量衰减仅3.2%。

Spinel LiMn2O4 was synthesized by reaction milling with KMnO4,MnSO4·H2O and LiOH·H2O as the raw material.The samples were characterized by XRD and SEM from structure and surface morphology.The results show that the sample after reaction milling is composed of LiMn2O4,Li2SO4·H2O and KLiSO4.After washing,the product is spinel LiMn2O4,but the crystallization degree is incomplete.After heating at 800 ℃ for 30 min,the synthesized LiMn2O4 is complete crystal,and its grains are fine and uniform with an average diameter of about 500 nm.And its initial discharge capacities are 115.8,107,105.5,98.2 mA·h/g at these discharge rates of 0.2,0.5,1 and 3 C,respectively,based on electrochemical tests.It is also of an excellent cycle performance with only 3.2% capacity fading degree after 10 cycles.