Acta Phys. -Chim. Sin. ›› 2005, Vol. 21 ›› Issue (11): 1285-1290.doi: 10.3866/PKU.WHXB20051118

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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

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