LiAlO_2包覆尖晶石LiMn_2O_4及电化学性能研究  

Preparation of Li Al O_2 coated spinel Li Mn_2O_4 and its electrochemical properties

作　　者：陈守彬[1] 吴显明[1,2] 陈上[1,2] 刘志雄[1] 丁其晨[1] 

机构地区：[1]吉首大学化学化工学院,湖南吉首416000 [2]湘西自治州矿产与新材料技术创新服务中心,湖南吉首416000

出　　处：《现代化工》2016年第4期68-71,共4页Modern Chemical Industry

基　　金：国家自然科学基金项目(21263004)

摘　　要：采用超声辅助溶液法在尖晶石Li Mn_2O_4表面包覆LiAlO_2。通过X射线衍射、扫描电子显微镜、恒电流充放电及交流阻抗技术分析合成材料的结构、粒径、形貌及电化学性能。XRD测试结果表明:LiAlO_2包覆Li Mn_2O_4与Li Mn_2O_4的X射线衍射结果相差不大,包覆后的样品仍为尖晶石结构,没有出现杂质相。室温下0.2 C充放电时,包覆0.5%、1%、3%LiAlO_2的LiMn_2O_4首次放电比容量分别为123.3、120.2 m A·h/g和118.7 m A·h/g,低于未包覆Li Mn_2O_4的125.4 m A·h/g,但在1C和5C高倍率下,包覆3%LiAl O_2的Li Mn_2O_4放电比容量分别为107.8 m A·h/g和85.6 m A·h/g,高于未包覆的104.2 m A·h/g和64.1 m A·h/g。室温下以1 C倍率循环50次后,表面包覆3%LiAlO_2的Li Mn_2O_4的容量保持率比未包覆高出2.9%。LiAlO_2 coated spinel Li Mn_2O_4 is prepared by ultrasonic assisted solution method. The structure,surface morphology and electro-chemical performance of the resultant materials are characterized by X-ray diffraction,scanning electron microscope（ SEM）,galvanostatic charge-discharge technique and AC impedance spectroscope. The XRD results show that Li Mn_2O_4 and LiAlO_2-coated Li Mn_2O_4 have the similar X-ray diffraction patterns. They are spinel structure without impurity phase. When charge-discharge of 0. 2 C is cycled at room temperature,the initial discharge specific capacity of Li Mn_2O_4 coated with 0. 5%,1% and 3% of LiAlO_2 are 123. 3,120. 2 and 118. 7 m A·h / g,respectively,which are a bit smaller than that of the uncoated Li Mn_2O_4（ 125. 4 m A·h/g）. But when charge-discharges of 1C and 5C are performed,the discharge specific capacities of Li Mn_2O_4 coated with 3% LiAlO_2 are 107. 8 m A·h / g and 104. 2 m A·h / g,respectively,which are much higher than that of origin Li Mn_2O_4（ 102. 8 m A·h/g and 64. 1 m A·h/g,respectivley）.When the charge-discharge of 1C is cycled for 50 times at room temperature,the capacity retention of 3% LiAlO_2 coated Li Mn_2O_4 is higher than that of the uncoated one by 2. 9%.

关 键 词：锂离子电池 表面包覆 锰酸锂 电化学性能 

分 类 号：TM912[电气工程—电力电子与电力传动] TQ131[化学工程—无机化工]