化学学报 ›› 2011, Vol. 69 ›› Issue (02): 117-121.    下一篇

研究论文

改性Pechini方法合成富锂正极材料Li[Li(1/3-x/3)CoxMn(2/3-2x/3)]O2及性能研究

赵煜娟*,赵春松,孙召琴,冯海兰   

  1. (北京工业大学环境与能源工程学院 北京 100124)
  • 收稿日期:2010-07-23 修回日期:2010-09-06 出版日期:2011-01-28 发布日期:2010-09-19
  • 通讯作者: 赵煜娟 E-mail:zhaoyujuan@bjut.edu.cn

Synthesis and Characterization of Li-rich Cathode Materials Li[Li(1/3-x/3)CoxMn(2/3-2x/3)]O2 by Modified Pechini Method

ZHAO Yu-Juan, ZHAO Chun-Song, SUN Zhao-Qin, FENG Hai-Lan   

  1. (College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124)
  • Received:2010-07-23 Revised:2010-09-06 Online:2011-01-28 Published:2010-09-19

通过改性Pechini方法合成不同Co含量的富锂正极材料Li[Li(1/3-x/3)CoxMn(2/3-x/3)]O2 (x=0.4, 0.5, 0.6). XRD研究结果表明, 不同Co含量的富锂正极材料均具有良好的层状结构, 结晶度高. 电化学测试结果表明材料的初始容量随Co含量的增加而增加, 在200~220 mAh/g之间. 其中x=0.4材料的循环性能最佳, 在0.5 C (100 mA/g)时, 循环50次后的容量保持率为75%. 容量微分曲线研究结果表明在3.5 V以下出现了Mn4+/Mn3+的还原峰, 并随循环次数的增加峰面积加大. 循环过程的XRD研究表明, 随着充放电次数的增加, 富锂正极材料的层状结构逐渐向尖晶石相转变, 且有杂质相MOx (M=Co, Mn)生成, 导致容量衰减.

关键词: 锂离子电池, 富锂正极材料, 改性Pechini方法, 电化学性能

The Li-rich cathode materials Li[CoxLi(1/3-x/3)Mn(2/3-2x/3)]O2 with different Co contents (x=0.4, 0.5, 0.6) were synthesized by modified Pechini method. The results of XRD confirmed that the crystals of the Li-rich compounds possess layered structure and have good crystallinity. The initial discharge capacities of the compounds are high between 200~220 mAh/g, increasing with the increase of Co contents. The material with x=0.4 exhibits the best cycling property. The capacity retainment is about 75% after 50 cycles at 0.5 C (100 mA/g). The peak of Mn4+/Mn3+occurred below 3.5 V in the plots of dQ/dV, and the area of the peak increases with the cycle numbers. The results of the XRD during the cycling process show the layer structure of the Li-rich materials transfers to the spinel phase, and the impurities appears during the cycling, resulting in the capacity fade.

Key words: lithium ion batterie, Li-rich cathode material, modified Pechini method, electrochemical behaviors