Chem. J. Chinese Universities ›› 2022, Vol. 43 ›› Issue (2): 20210546.doi: 10.7503/cjcu20210546

• Physical Chemistry • Previous Articles     Next Articles

Effects of SmPO4 Coatingon Electrochemical Performance of High-voltage LiNi0.5Mn1.5O4 Cathode Materials

LI Xiaohui1,3, WEI Aijia1,2,3(), MU Jinping1,2,3, HE Rui1,3, ZHANG Lihui1,3, WANG Jun3, LIU Zhenfa1,3()   

  1. 1.Institute of Energy Resources,Hebei Academy of Sciences,Shijiazhuang 050081,China
    2.School of Chemical Engineering and Technology,Hebei University of Technology,Tianjin 300130,China
    3.Hebei Functional Materials Technology Innovation Center for Lithium Battery Electrolyte,Shijiazhuang 050081,China
  • Received:2021-08-02 Online:2022-02-10 Published:2021-12-04
  • Contact: LIU Zhenfa E-mail:weiaijia2012@126.com;lzf63@sohu.com
  • Supported by:
    the Project of Hebei Academy of Sciences, China(21709);the Hebei Province Major Scientific and Technological Achievements Transformation Project, China(20284401Z)

Abstract:

Spinel-type LiNi0.5Mn1.5O4 has been widely used in large-scale energy storage equipment, energy conversion equipment and power vehicle, due to its low preparation cost, high discharge platform and long cycle life. However, the electrolyte of LiNi0.5Mn1.5O4 decomposes easily under high voltage(5 V) charging, which leads to a decrease in specific capacity and a decline in cycling performance. To solve the above problems, the LiNi0.5Mn1.5O4 cathode material was successfully coated with a thin layer of SmPO4via a hydrothermal process. The influence of the coating amount of SmPO4 on the electrochemical performance of LiNi0.5Mn1.5O4 material was systematically studied. The results indicate that the as-prepared LiNi0.5Mn1.5O4 coated with 0.5%(mass fraction) SmPO4(LNMO@SP-0.5) exhibits optimal electrochemical performance. In case of 0.2C and 5C, the discharge specific capacity of LNMO@SP-0.5 was 129.2and 90.9 mA?h/g, respectively, while Pristine LNMO only had 114.2 and 77.7 mA?h/g. LNMO@SP-0.5 exhibited a capacity retention of 93.4% after 500 cycles at 5C and 25 ℃, whereas the Pristine LNMO exhibited a poor capacity retention of 86.6%. The improvement was due to SmPO4 coating can effectively alleviate the side reaction between LiNi0.5Mn1.5O4 material and electrolyte, and reduce the polarization degree and charge transfer resistance of the electrode, and increase the diffusion coefficient of Li+.

Key words: Spinel-type LiNi0.5Mn1.5O4, Coathode material, SmPO4 Coating layer, Hydrothermal method

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