物理化学学报 >> 2012, Vol. 28 >> Issue (05): 1183-1188.doi: 10.3866/PKU.WHXB201202221

电化学和新能源 上一篇    下一篇

机械活化辅助多元醇法合成锂离子正极材料LiFePO4

曹雁冰1,2, 段建国1, 姜锋2, 胡国荣1, 彭忠东1, 杜柯1   

  1. 1. 中南大学冶金科学与工程学院, 长沙 410083;
    2. 中南大学材料科学与工程学院, 长沙 410083
  • 收稿日期:2011-11-02 修回日期:2012-02-04 发布日期:2012-04-26
  • 通讯作者: 曹雁冰 E-mail:cybcsu@csu.edu.cn
  • 基金资助:

    国家科技支撑计划项目(2007BAE12B01)和湖南省科技计划项目(2009GK3150)资助

Synthesis of LiFePO4 Cathode Materials by Mechanical-Activation-Assisted Polyol Processing

CAO Yan-Bing1,2, DUAN Jian-Guo1, JIANG Feng2, HU Guo-Rong1, PENG Zhong-Dong1, DU Ke1   

  1. 1. School of Metallurgical Science and Engineering, Central South University, Changsha 410083, P. R. China;
    2. School of Materials Science and Engineering, Central South University, Changsha 410083, P. R. China
  • Received:2011-11-02 Revised:2012-02-04 Published:2012-04-26
  • Contact: CAO Yan-Bing E-mail:cybcsu@csu.edu.cn
  • Supported by:

    The project was supported by the National Key Technology Research and Development Program of China (2007BAE12B01) and Technology Research and Development Program of Hunan Province, China (2009GK3150).

摘要: 以LiH2PO4和还原铁粉为原料, 通过机械液相活化法获得了棒状形貌的[Fe3(PO4)2·8H2O +Li3PO4]前驱体, 然后在三甘醇(TEG)介质中采用多元醇工艺制备了LiFePO4材料. 为提高其电导率, 以聚乙烯醇(PVA)为碳源, 对纯相LiFePO4进行碳包覆改性. 通过X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、恒电流充放电和电化学阻抗谱(EIS)等测试方法对制备的材料进行了表征. 结果表明:采用机械活化辅助多元醇法可在低温下合成结晶良好的LiFePO4, 碳包覆改性的LiFePO4/C 材料导电性能得到改善, 电荷转移阻抗减小, 1C、2C倍率下放电容比量分别为139.8、129.5 mAh·g-1, 具有良好的倍率性能和循环稳定性.

关键词: 正极材料, LiFePO4, 机械活化, 多元醇法, 碳包覆

Abstract: A low-temperature approach for efficient preparation of LiFePO4 was developed. The rod-shaped [Fe3(PO4)2·8H2O + Li3PO4] precursor was prepared, using a mechanochemical liquid-phase activation technique, from LiH2PO4 and reduction iron powder. Pure LiFePO4 was then synthesized in boiling tetra(ethylene glycol) (TEG) by polyol processing with the as-prepared precursor. In order to improve the electrical conductivity, carbon coating of the pure LiFePO4 was carried out, using poly(vinyl alcohol) (PVA) as the carbon source. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), galvanostatic charge-discharge test and electrochemical impedance spectroscopy (EIS). The results show that well-crystallized LiFePO4 was successfully synthesized by polyol processing at low temperature. Carbon coating significantly improves the conductive properties of LiFePO4 and reduces charge-transfer impedance. The obtained LiFePO4/C composite delivers specific discharge capacities of 139.8 and 129.5 mAh·g-1 at 1C and 2C rates, respectively, displaying good cycling performance and rate capability.

Key words: Cathode Material, LiFePO4, Mechanical activation, Polyol processing, Carbon coating

MSC2000: 

  • O646