物理化学学报 >> 2005, Vol. 21 >> Issue (11): 1285-1290.doi: 10.3866/PKU.WHXB20051118

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LiNiyCo0.1－yMn1.9O4正极材料的沉淀法制备及其结构与电化学性能

王国光; 王建明; 毛文曲; 刘立清; 张鉴清; 曹楚南   

  1. 浙江大学化学系, 杭州 310027; 中国科学院金属研究所, 金属腐蚀与防护国家重点实验室, 沈阳 110016
  • 收稿日期:2005-04-05 修回日期:2005-05-09 发布日期:2005-11-15
  • 通讯作者: 王建明 E-mail:wjm@cmsce.zju.edu.cn

Structure and Electrochemical Performance of LiNiyCo0.1－yMn1.9O4 Cathode Materials Prepared by a Precipitation Method

WANG Guo-guang WANG Jian-ming MAO Wen-qu LIU Li-qing ZHANG Jian-qing CAO Chu-nan   

  1. Department of Chemistry, Zhejiang University, Hangzhou 310027; State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016
  • Received:2005-04-05 Revised:2005-05-09 Published:2005-11-15
  • Contact: WANG Jian-ming E-mail:wjm@cmsce.zju.edu.cn

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摘要： 采用沉淀法制备了尖晶石型LiMn2O4和LiNiyCo0.1－yMn1.9O4 (y=0, 0.05, 0.1)正极材料. 应用FT-IR、XRD和SEM技术对不同掺杂样品的相结构与形貌进行了表征, 并用恒电流充放电测试和电化学阻抗技术研究了样品的电化学行为. FT-IR、XRD和SEM结果显示: 随着掺杂型LiNiyCo0.1－yMn1.9O4 样品中Ni含量的减少, 位于519 cm-1处的红外峰向高频方向移动; Ni、Co 或Ni/Co的掺杂降低了LiMn2O4的晶格参数; 掺杂型 LiNiyCo0.1－yMn1.9O4 样品具有更好的分散度和小的粒径. 电化学实验结果表明, 不同成分的掺杂导致电化学性能改善的原因不尽相同. 其中LiNi0.05Co0.05Mn1.9O4样品因其较低的电化学极化和较大的Li+扩散系数而具有较好的电化学性能.

关键词: 锂离子电池, 掺杂锂锰氧尖晶石, 沉淀法, 电化学性质

Abstract: Spinel LiMn2O4 and LiNiyCo0.1－yMn1.9O4 (y=0, 0.05, 0.10) samples were prepared by a precipitation method. The structure, morphology, and electrochemical performance of the samples were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron micrographs (SEM), charge-discharge measurements, and electrochemical impedance spectra (EIS). The results of FT-IR and XRD indicated that the absorption band at about 519 cm-1 shifts to the high frequency with the decrease of Ni content in LiNiyCo0.1－yMn1.9O4 samples and the lattice parameter(a) of LiMn2O4 samples decreases with the addition of Ni, Co, or Ni/Co. The SEM observation displayed that the LiNiyCo0.1－yMn1.9O4 samples have lower agglomeration degree and smaller particle size. The results of the electrochemical experiments showed that the improvements on the electrochemical performance of substituted samples have some different reasons, and the LiNiyCo0.1－yMn1.9O4 sample manifests better electrochemical performance in 4 V region due to its lower electrochemical polarization and larger diffusion coefficient of Li+ ions.

Key words: Lithium ion batteries, Substituted manganese spinel oxide, Precipitation, Electrochemical properties