物理化学学报 >> 2010, Vol. 26 >> Issue (06): 1507-1514.doi: 10.3866/PKU.WHXB20100638

电化学 上一篇    下一篇

湿化学法合成LiNi1/3Mn1/3Co1/3O2及其表征

张晓雨, 江卫军, 朱晓沛, 其鲁   

  1. 北京大学化学与分子工程学院应用化学系, 北京 100871; 中信国安盟固利电源技术有限公司, 北京 102200
  • 收稿日期:2010-02-09 修回日期:2010-03-24 发布日期:2010-05-28
  • 通讯作者: 其鲁 E-mail:qilu@pku.edu.cn

Characterization of LiNi1/3Mn1/3Co1/3O2 Synthesized by Wet-Chemical Method

ZHANG Xiao-Yu, JIANG Wei-Jun, ZHU Xiao-Pei, QI Lu   

  1. Department of Applied Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China; CITIC Guoan Mengguli Power Source Technology Co., Ltd., Beijing 102200, P. R. China
  • Received:2010-02-09 Revised:2010-03-24 Published:2010-05-28
  • Contact: QI Lu E-mail:qilu@pku.edu.cn

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摘要：

利用琥珀酸为鳌合剂的湿化学法成功合成了一系列锂离子电池正极材料LiNi1/3Mn1/3Co1/3O2, 在合成过程中改变琥珀酸与金属离子摩尔比(R)并研究了这一参数对合成LiNi1/3Mn1/3Co1/3O2材料物理及电化学性质的影响. 采用热重、X射线衍射、Rietveld精修、扫描电镜以及超导量子干涉仪对反应机理、材料的结构、形貌以及磁学性质进行了详细表征. 得到最佳合成条件为R=1, 此时LiNi1/3Mn1/3Co1/3O2的阳离子混排度最低. 此外, 通过Rietveld精修得到该材料阳离子混排度的结果与通过磁学方法得到的结果定量相符, 如对于在R=1条件下合成的样品, Rietveld精修结果显示其阳离子混排度为1.85%, 而超导量子干涉仪的测试结果为1.80%. 当充放电区间为3.0-4.3 V, 电流密度为0.2C (1C=160 mA·g-1)时, 该样品的首次放电容量为161 mAh·g-1, 库仑效率为93.1%, 经过50次循环后, 容量保持率可达91.3%.

关键词: 锂离子电池, LiNi1/3Mn1/3Co1/3O2, 湿化学法, 阳离子混排, 磁学性质

Abstract:

A series of cathode materials LiNi1/3Mn1/3Co1/3O2 for lithium-ion batteries were successfully synthesized using succinic acid as a chelating agent by a wet-chemical method. We varied the succinic acid to metal-ion molar ratios (R) and investigated the effect of this parameter on the physical and electrochemical properties of the prepared LiNi1/3Mn1/3Co1/3O2. The reaction mechanism, structural, morphological, and magnetic properties of the powders were characterized in detail by thermogravimetry (TG), X-ray diffraction (XRD), Rietveld refinement, scanning electron microscopy (SEM), and superconducting quantuminterface device (SQUID).We determine that the optimumconditions for the synthesis of LiNi1/3Mn1/3Co1/3O2 assisted with succinic acid is R=1, at the lowest amount of cation mixing. In addition, measurement of the magnetic properties revealed a concentration of Ni on the 3b Wyckoff site of the lithium-ions in good agreement with the results from the Rietveld refinement on the XRD spectra. For LiNi1/3Mn1/3Co1/3O2 (R=1), the Rietveld refinement showed that cation mixing in this sample was 1.85%, which is in quantitative agreement with that fromthe SQUIDresult (1.80%). It delivered an initial discharge capacity of 161 mAh·g-1 at a current rate of 0.2C (1C=160 mA·g-1) and at a cut-off voltage of 3.0-4.3 V with a coulombic efficiency of 93.1% and its capacity retention was 91.3% after 50 cycles.

Key words: Lithium-ion battery, LiNi1/3Mn1/3Co1/3O2, Wet-chemical method, Cation mixing, Magnetic property