高等学校化学学报

高等学校化学学报 ›› 2013, Vol. 34 ›› Issue (7): 1709.doi: 10.7503/cjcu20121057

• 物理化学 • 上一篇    下一篇

Li2MnSiO4/CNTs复合正极材料的合成与电化学性能

高伟1, 包丽颖1,2, 苏岳锋1,2, 田君1, 刘伟1, 陈实1,2, 吴锋1,2   

  1. 1. 北京理工大学化工与环境学院, 北京 100081;
    2. 国家高技术绿色材料发展中心, 北京 100081
  • 收稿日期:2012-11-22 出版日期:2013-07-10 发布日期:2013-06-21
  • 通讯作者: 苏岳锋, 男, 博士, 副教授, 主要从事锂离子电池电极材料研究. E-mail: suyuefeng@bit.edu.cn E-mail:suyuefeng@bit.edu.cn
  • 基金资助:

    国家"九七三"计划项目(批准号: 2009CB220100);国家自然科学基金青年科学基金(批准号: 51102018, 21103011)和国家"八六三"计划项目(批准号: 2011AA11A235, SQ2010AA1123116001)资助.

Preparation and Electrochemical Performance of Li2MnSiO4/CNTs Composite Cathode Material for Lithium Ion Batteries

GAO Wei1, BAO Li-Ying1,2, SU Yue-Feng1,2, TIAN Jun1, LIU Wei1, CHEN Shi1,2, WU Feng1,2   

  1. 1. School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing 100081, China;
    2. National Development Center of High Technology Green Materials, Beijing 100081, China
  • Received:2012-11-22 Online:2013-07-10 Published:2013-06-21

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摘要：

采用水热辅助溶胶-凝胶工艺, 通过原位复合的方法合成了锂离子电池用Li2MnSiO4/CNTs复合正极材料. 分析了复合正极材料的形貌和组成特征, 并对每摩尔分别复合5, 10, 20和30 g碳纳米管(CNTs)及未复合CNTs的样品进行了电化学性能测试. 结果显示, 所合成的Li2MnSiO4颗粒尺寸分布均匀, 粒径在100 nm左右, 易团聚. 但随着CNTs复合量的增加, 团聚现象逐渐改善. 合成的Li2MnSiO4材料结晶度良好, 属于正交晶系Pmn21空间群. 电化学测试结果表明, 每摩尔复合20 g CNTs的样品电化学性能最佳, 在10 mA/g电流密度下, 首周放电容量为150 mA·h/g, 循环20周后仍保持在80 mA·h/g; CNTs的原位复合可提高Li2MnSiO4材料的导电性能, 并改善其电化学性能.

关键词: 锂离子电池, 正极材料, Li2MnSiO4, 碳纳米管

Abstract:

Li2MnSiO4/CNTs composite cathode material for lithium ion batteries was in situ synthesized by the sol-gel process assisted with hydrothermal method. The crystalline structure and morphology of the obtained samples containing 0, 5, 10, 20 and 30 g carbon nanotubes(CNTs) in 1 mol Li2MnSiO4, respectively, were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and their electrochemical performances were evaluated by different electrochemical test. The results show that the grains of samples have narrow size distribution and their dimension is about 100 nm. They are easy to be an agglomerate mass and the agglomeration of the samples is gradually reduced with the increase of the contents of CNTs. The XRD patterns reveal that the well-crystallized Li2MnSiO4/CNTs materials are orthorhombic with space group Pmn21. The sample with 20 g CNTs in 1 mol Li2MnSiO4(the carbon content is 16.74%) demonstrates the best electrochemical performance, showing an initial discharge capacity of 150 mA·h/g and a discharge capacity of 80 mA·h/g after 20 cycles at 10 mA/g current density. The in situ composite of CNTs could improve the overall conductivity and the electrochemical performance of Li2MnSiO4 cathode materials.

Key words: Lithium ion battery, Cathode material, Li2MnSiO4, Carbon nanotubes

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