Acta Phys. -Chim. Sin. ›› 2009, Vol. 25 ›› Issue (04): 629-634.doi: 10.3866/PKU.WHXB20090411

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Surface Modification of LiCo1/3Ni1/3Mn1/3O2 by TiO2-Coating

 WU Feng, WANG Meng, SU Yue-Feng, CHEN Shi   

  1. National Development Center of High Technology Green Materials, School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing 100081, P. R. China
  • Received:2008-11-19 Revised:2008-12-25 Published:2009-03-31
  • Contact: SU Yue-Feng


A method to improve the cycling performance of LiCo1/3Ni1/3Mn1/3O2 in lithium-ion batteries by coating with TiO2 using an in-situ dipping and hydrolyzing method was presented in this work. The effect of the TiO2 coating on the structure and electrochemical properties of LiCo1/3Ni1/3Mn1/3O2 was investigated using X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), inductively coupled plasma-optical emission spectroscopy (ICP-OES), and galvanostatic charge/discharge testing. TiO2 forms a layer on the surface of LiCo1/3Ni1/3Mn1/3O2 without destroying the structure of the core material. The TiO2-coated LiCo1/3Ni1/3Mn1/3O2 possesses better rate capability and cyclability than the uncoated material. The capacity of the TiO2-coated material at 5.0C (1.0C=160 mA·g-1) reaches 66.0% of that achieved at 0.2C, while the capacity of the uncoated LiCo1/3Ni1/3Mn1/3O2 obtains a value of only 31.5%. The rate of capacity retention after 12 cycles at 2.0C for the coated sample is about 100%, which is much better than that of the uncoated material (94.4%). EIS shows that the reason for this improvement in the capacity of the coated material is the enhanced interface stability during cycling. XRD and ICP-OES tests taken after cycling indicate that the TiO2-coating can enhance the structural stability of LiCo1/3Ni1/3Mn1/3O2.

Key words: TiO2-coating, LiCo1/3Ni1/3Mn1/3O2, Cycling performance, Lithium-ion battery


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