物理化学学报 >> 2011, Vol. 27 >> Issue (09): 2123-2128.doi: 10.3866/PKU.WHXB20110902

电化学和新能源 上一篇    下一篇

溶胶-凝胶法制备多孔LiMnPO4/MWCNT复合材料及其电化学性能

聂平, 申来法, 陈琳, 苏晓飞, 张校刚, 李洪森   

  1. 1. 新疆大学化学化工学院, 乌鲁木齐 830046;
    2. 南京航空航天大学材料科学与技术学院, 南京 210016
  • 收稿日期:2011-05-23 修回日期:2011-06-20 发布日期:2011-08-26
  • 通讯作者: 张校刚 E-mail:azhangxg@163.com
  • 基金资助:

    国家重点基础研究发展计划项目(973) (2007CB209703), 国家自然科学基金(20873064), 江苏省普通高校科研创新计划(CXZZ11_0204)及南京航空航天大学博士学位论文创新与创优基金(BCXJ11-10)资助

Sol-Gel Synthesis and Electrochemical Performance of Porous LiMnPO4/MWCNT Composites

NIE Ping, SHEN Lai-Fa, CHEN Lin, SU Xiao-Fei, ZHANG Xiao-Gang, LI Hong-Sen   

  1. 1. College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi 830046, P. R. China;
    2. College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, P. R. China
  • Received:2011-05-23 Revised:2011-06-20 Published:2011-08-26
  • Contact: ZHANG Xiao-Gang E-mail:azhangxg@163.com
  • Supported by:

    The project was supported by the National Key Basic Research Program of China (973) (2007CB209703), National Natural Science Foundation of China (20873064), Jiangsu Innovation Program for Graduate Education, China (CXZZ11_0204) and Outstanding Doctoral Dissertation in NUAA, China (BCXJ11-10).

摘要: 以柠檬酸为络合剂, 采用溶胶-凝胶法制备了多孔LiMnPO4和LiMnPO4/MWCNT(多壁碳纳米管)复合材料. 用X射线衍射(XRD)、场发射扫描电镜(FE-SEM)、N2吸脱附等温曲线(BET)和透射电镜(TEM)对其晶体结构与微观形貌进行了表征. 结果表明, 得到的样品具有橄榄石晶体结构, 物相较纯; 两种材料均具有丰富的多级孔道结构, 孔径在介孔范围内分布集中, 比表面积分别为73.7、69.9 m2·g-1; 碳纳米管以嵌入或包埋的形式在多孔LiMnPO4中形成了高导电性的三维网络. 恒流充放电测试表明, 与纯LiMnPO4相比, 复合材料具有更高的放电比容量, 在0.05C、2C倍率下的放电容量分别为108.8、33.2 mAh·g-1. 电化学交流阻抗谱(EIS)表明MWCNT可以有效提高LiMnPO4的电子导电性. LiMnPO4/MWCNT复合材料具有较优的电化学性能可归因于增强的电子导电性, 连接的孔道结构和高的比表面积.

关键词: LiMnPO4, 碳纳米管, 多孔材料, 溶胶-凝胶法, 锂离子电池

Abstract: Porous LiMnPO4 and LiMnPO4/MWCNT (multi-walled carbon nanotube) composites were prepared using a citric acid assisted sol-gel method. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), nitrogen adsorption-desorption isotherms (BET), and transmission electron microscopy (TEM) were performed to characterize their morphologies and structures. The results indicated that fine-sized, well-crystallized olivine LiMnPO4 was synthesized. The interlaced carbon nanotube networks were intimately embedded and incorporated into the porous LiMnPO4 particle to form highlyconductive three-dimensional (3D) networks. The LiMnPO4 particle and LiMnPO4/MWCNT composite had rich hierarchical pores. A detailed analysis showed that the average pore size was in the mesoporous range and specific surface areas of 73.7 and 69.9 m2·g-1 were obtained, respectively. Compared with the LiMnPO4 particle the LiMnPO4/MWCNT composite exhibited much higher specific capacity. When discharged at a rate of 0.05C and 2C the capacities were 108.8 and 33.2 mAh·g-1, respectively. The MWCNT effectively improved the electronic conductivity of the hybrid materials as shown by electrochemical impedance spectroscopy (EIS). The improved electrochemical performance of the LiMnPO4/MWCNT electrode is attributed to the enhanced electrical conductivity caused by the tighter binding of the carbon nanotubes with the LiMnPO4 primary particles as well as by the interconnected open pores with a high surface area.

Key words: Lithium manganese phosphate, Carbon nanotube, Porous material, Sol-gel method, Lithium ion battery

MSC2000: 

  • O646