J. Mater. Sci. Technol. ›› 2025, Vol. 209: 230-239.DOI: 10.1016/j.jmst.2024.04.068

• Research Article • Previous Articles     Next Articles

Atomically dispersed Fe-N5 coordination structure anchored in defective g-C3N4 as oversaturated asymmetric single-atom catalysts for accelerating redox kinetics in Li-S batteries

Jun Wanga, Jinxin Wanga, Yongzheng Zhanga, Cheng Mab,*, Jitong Wanga,c,*, Wenming Qiaoa, Licheng Linga,*   

  1. aState Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai, 200237, China;
    bKey Laboratory of Specially Functional Polymeric Materials and Related Technology (Ministry of Education), School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, China;
    cGuangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning, 530004, China
  • Received:2024-03-04 Revised:2024-04-08 Accepted:2024-04-17 Published:2025-02-20 Online:2024-05-21
  • Contact: *State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai, 200237, China. E-mail addresses: mac@mail.ecust.edu.cn (C. Ma), wangjt@ecust.cn (J. Wang), lchling@ecust.edu.cn (L. Ling)

Abstract: Lithium-sulfur (Li-S) batteries are regarded as the most formidable competitor to lithium-ion batteries due to their superior theoretical capacity. However, the negative impact of soluble lithium polysulfide (LiPSs) and slow redox reaction kinetics seriously hamper the commercialization of Li-S batteries. In this study, a defect-rich single-atom catalyst with an oversaturated asymmetric Fe-N5 coordination structure anchored in defective g-C3N4 (C3N4-Fe@rGO) is designed via an absorption-pyrolysis strategy. The two-dimensional (2D) conducting C3N4@graphene structure with abundant defect sites accelerates the transfer and transportation of lithium ions and electrons. The oversaturated asymmetric Fe-N5 coordination structure effectively improves the adsorbility of LiPSs and accelerates the redox kinetics of sulfur species. Hence, the Li-S cell with a C3N4-Fe@rGO modified separator reveals a high initial capacity (1197.1 mAh g-1 at 0.2 C) and a low capacity decay rate (0.037 % per cycle after 900 cycles at 1 C). Even at high sulfur loading and extreme temperatures of 0 °C, it also shows good cycling performance. This work creates ideas for synthesizing oversaturated single-atom coordination environments and an efficient route to the practical realization of the Li-S batteries.

Key words: Defective, Oversaturated asymmetric, Single-atom Fe catalyst, Sulfur conversion kinetics, Lithium-sulfur batteries