摘要
以多壁碳纳米管(multi-walled carbon nanotubes,MWCNTs)作为正极材料导电剂制备了LiMn2O4/MWCNTs复合电极。扫描电镜照片显示:MWCNTs形成三维网状结构并且均匀的分散在LiMn2O4活性颗粒之间。以1C倍率进行充放电测试,质量分数分别为2%,5%和8%MWCNTs的正极材料首次放电容量为分别为96.0,105.5mAh/g和114.8mAh/g。质量比为5%的乙炔黑(acetylene black,AB)电极放电容量为98.0mAh/g,说明MWCNTs能有效提高电极材料的电子电导率以及活性物质的利用率。交流阻抗测试结果表明:电极过程中电荷传递电阻随MWCNTs含量的增加而减小,并由此计算得出相同导电剂含量的LiMn2O4/MWCNTs和LiMn2O4/AB复合电极的电荷传递活化能为27.5kJ/mol和32.3kJ/mol。
Composite anodes of LiMn2O4/multi-walled carbon nanotubes （MWCNTs） were prepared by mixing LiMn2O4 particles with MWCNTs as electric agent. The morphology was analyzed by scanning electron microscope, and LiMn2O4 particles were connected by MWCNTs to form a three-dimensional network wiring. Electron transport and electrochemical activity were improved effectively by the web wiring structure. Galvanostatic charge/discharge tests at a rate of 1 C show that the initial discharge capacities are 96.0, 105.5 mAh/g and 114.8 mAh/g, respectively when the contents of MWCNTs are 2%, 5% and 8% compared to 98.0 mAh/g with 5% acetylene black（AB）. The electrochemical alternating current （AC） impedance spectroscopy results show that during the electrochemical reaction process the charge transfer resistance decrease obviously with the increase of the content of MWCNTs. The activation energy values of LiMn2O4/MWCNTs and LiMn2O4/AB composite cathodes with the same content of MWCNTs or acetylene black are calculated to be 27.5 kJ/mol and 32.3 kJ/mol, respectively according to electrochemical impedance spectra measurement at different temperatures.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2008年第9期1319-1324,共6页
Journal of The Chinese Ceramic Society
关键词
锂离子电池
复合电极
电化学性质
交流阻抗
lithium ion battery
composite electrode
electrochemical character
alternating current impedance
作者简介
刘素琴（1965-），女，博士，教授。
