Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (08): 1899-1905.doi: 10.3866/PKU.WHXB201205152

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Improved Electrochemical Stability of Zn-Doped LiNi1/3Co1/3Mn1/3O2 Cathode Materials

LI Jie-Bin1,2, XU You-Long1, DU Xian-Feng1, SUN Xiao-Fei1, XIONG Li-Long1   

  1. 1. Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, International Center for Dielectric Research, Xi’an Jiaotong University, Xi’an 710049, P. R. China;
    2. Shaanxi Applied Physics and Chemistry Research Institute; Xi'an 710061, P. R. China
  • Received:2012-03-15 Revised:2012-05-14 Published:2012-07-10
  • Contact: XU You-Long E-mail:ylxuxjtu@mail.xjtu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation (50902109).

Abstract:

Highly stable Li(Ni1/3Co1/3Mn1/3)1-xZnxO2 (x=0, 0.02, 0.05) cathode materials doped with Zn are synthesized by solid-state reactions with co-precipitated precursors. Cyclic voltammetry (CV) curves reveal that the potential difference between oxidation and reduction decreases to 0.09 V, and from electrochemical impedance spectra (EIS) curves, the impedance of LiNi1/3Co1/3Mn1/3O2 cathode materials is reduced from 266 to 102 Ω. The diffusion coefficients of Li+ ions in intercalation processes increase from 1.20×10-11 to 2.54×10-11 cm2·s-1. Li(Ni1/3Co1/3Mn1/3)0.98Zn0.02O2 is stable at 0.3C (constant charge/discharge) at a high cut-off potential of 4.6 V vs Li/Li+. It has a second discharge capacity of 176.2 mAh·g-1 at 0.3C and 142 mAh·g-1 at 3C, and keep almost no decay after 100 cycles at room temperature. Furthermore, its average capacity loss per cycle at 55 °C is 0.20%, which is lower compared with 0.54% for LiNi1/3Co1/3Mn1/3O2 and 0.38% for Li(Ni1/3Co1/3Mn1/3)0.95Zn0.05O2 after 100 cycles. The improved electrochemical stability of Zn-doped LiNi1/3Co1/3Mn1/3O2 is attributed to the reduced electrode polarization and impedance values, and an increased Li+ ion diffusion coefficient.

Key words: Lithium nickel cobalt manganese oxide, High cut-off voltage, Zn-doping, Cathode material, Lithium ion battery

MSC2000: 

  • O646