Encapsulating Co9S8 nanocrystals into CNT-reinforced N-doped carbon nanofibers as a chainmail-like electrocatalyst for advanced Li-S batteries with high sulfur loading

Jintao LIU, Shuhao XIAO, Xingquan LIU, Rui WU, Xiaobin NIU, Yong XIANG, Jun Song CHEN*, Chenghao YANG

*Corresponding author for this work

Research output: Journal PublicationsJournal Article (refereed)peer-review

48 Citations (Scopus)

Abstract

Li-S batteries have been regarded as one promising candidate for next-generation energy storage systems, however, their practical implementations are severely hindered by the intractable polysulfides shuttle (PSS) effect and retarded conversion kinetics. Herein, a flexible electrode consisting of Co9S8 nanocrystals and CNTs encapsulated inside porous N-doped carbon nanofibers (NCF) (CNT@NC/Co9S8) was developed by electrospinning followed by in-situ sulfurization. The carbon nanofibers and embedded CNTs build a highly conductive network, while the Co9S8 and N dopant provide more polar sites for LiPSs confinement. This self-supported flexible electrode with a sulfur loading of 12.5 mg cm−2 exhibits a high initial discharge capacity (1207.7 mAh g−1 at 0.1C), excellent rate capability (831.2 mAh g−1 at 4.0C) and cycling stability (765.5 mAh g−1 with a capacity retention of 78.1% after 1000 cycles at 2.0C). Moreover, when the sulfur loading increases to 20 and 30 mg cm−2, high capacities of 869.2 and 706.6 mAh g−1can still be obtained at 0.1C after 100 cycles, respectively. Theoretical analysis suggests that the sulfur cathode built on CNT@NC/Co9S8 is electrocatalytically active towards LiPSs redox with enhanced conversion dynamics, thus mitigating the detrimental PSS effect.

Original languageEnglish
Article number130246
JournalChemical Engineering Journal
Volume423
DOIs
Publication statusPublished - 1 Nov 2021
Externally publishedYes

Bibliographical note

We gratefully acknowledge the financial support from the National Natural Science Foundation of China (Nos. 51872098 and 51922042), Fundamental Research Funds for the Central Universities, China (Nos. ZYGX2019J030 and 2020ZYGXZR074), and Sichuan Science and Technology Program (No. 2020YJ0299).

Keywords

  • Chainmail-like electrocatalyst
  • CoS nanocrystals
  • First-principle calculations
  • High sulfur loading
  • Li-S batteries

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