聚吡咯包覆尖晶石LiMn_2O_4微球的合成及其电化学储锂性能  

Synthesis and Electrochemical Performance of Spinel LiMn_2O_4 Surface Coated with Polypyrrole

作　　者：张堃[1] 李桂村[1] ZHANG Kun LI Guicun(College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, Chin)

机构地区：[1]青岛科技大学材料科学与工程学院,山东青岛266042

出　　处：《青岛科技大学学报（自然科学版）》2016年第5期533-538,共6页Journal of Qingdao University of Science and Technology:Natural Science Edition

摘　　要：利用共沉淀法合成MnCO_3微球与Li_2CO_3进行固相反应制备了尖晶石LiMn_2O_4微球。通过吡咯在LiMn_2O_4表面上进行化学氧化聚合合成了聚吡咯包覆LiMn_2O_4微球(PPy@LiMn_2O_4)。聚吡咯包覆层不仅可以提高LiMn_2O_4微球的电子导电率,而且其本身像一个电容器。这种结构特点有利于提高LiMn_2O_4的容量,倍率性能和高倍率循环稳定性。通过循环伏安(CV)、交流阻抗(EIS)和恒流充放电等方法测试了电极材料的电化学性能,研究表明:PPy@LiMn_2O_4显示了比LiMn_2O_4微球更好的电化学储锂性能,包括高比容量(118.4 mA·h·g^(-1))、高倍率性能(5C,104.5 mA·h·g^(-1))。Spinel lithium manganese oxide（LiMn2O4）microspheres have been prepared by solid state reaction between Li2CO3 and MnCO3 microspheres obtained by co-precipitation method.Polypyrrole coated LiMn2O4 microspheres（PPy@LiMn2O4）have been synthesized by the chemical oxidation polymerization of pyrrole on the surfaces of LiMn2O4 microspheres.The polypyrrole coating can not only increase the electronic conductivity of LiMn2O4 microspheres,but also behaves like a capacitor.The structure features are favorable for improving the capacity density,rate capability and cycling stability of LiMn2O4.Electrochemical properties have been studied by cyclic voltammetry（CV）,electrochemical impedance spectroscopy（EIS）and galvanostatic charge/discharge tests at various current rates.When used as cathode materials,PPy@LiMn2O4exhibit better electrochemical lithium storage performances including high specific capacity（118.4mA·h·g^-1）and rate capability（104.5mA·h·g^-1 at 5C）.

关 键 词：锂离子电池 锰酸锂 聚吡咯 包覆 

分 类 号：TM912.9[电气工程—电力电子与电力传动]