Chem. J. Chinese Universities ›› 2022, Vol. 43 ›› Issue (8): 20220163.doi: 10.7503/cjcu20220163

• Physical Chemistry • Previous Articles     Next Articles

Enhance of CoSe2/C Composites Modified Separator on Electrochemical Performance of Li-S Batteries at High Sulfur Loading

HAN Fuchao1, LI Fujin1, CHEN Liang1(), HE Leiyi1, JIANG Yunan1, XU Shoudong1, ZHANG Ding1, QI Lu2   

  1. 1.College of Chemistry and Chemical Engineering,Taiyuan University of Technology,Taiyuan 030024,China
    2.College of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China
  • Received:2022-03-15 Online:2022-08-10 Published:2022-05-06
  • Contact: CHEN Liang E-mail:chenliang@tyut.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(21706171)

Abstract:

Herein, CoSe2/C composite was obtained by a simple two-step calcining method with the rhombohedral dodecahedral ZIF-67 as the template. The CoSe2 nanoparticles with diameters of approximately 30 nm were dispersed in the carbon skeleton maintaining the structure of the template. Systematically electrochemical results demonstrated that the CoSe2/C composite could fasten the kinetics of the soluble lithium polysulfides, as well as guide the deposition of the insoluble Li2S during the discharge process. In addition, the CoSe2/C could also boost the oxidation of Li2S. It was loaded on commercial Celgard 2400 separators as the electrocatalytic materials. It is worth to note that the mass loading of the modified layer is only 0.15 mg/cm2, in which the CoSe2/C composite only accounts for 30%(mass fraction). Consequently, the cells with CoSe2/C-modified separator delivered a superior electrochemical performance, which with a high sulfur loading of 4.8 mg/cm2 gave an initial specific capacity of 756 mA·h/g at 0.2C and maintained at 715 mA·h/g after 180 cycles, with a capacity decay rate of 0.031% per cycle.

Key words: Li-S battery, Electrocatalysis, CoSe2, Modified separator, Shuttle effect

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