Low-Coordinated Zn-N2 Sites as Bidirectional Atomic Catalysis for Room-Temperature Na-S Batteries

Daliang Fang, Shaozhuan Huang, Tingting Xu, Pan Sun, Xue Liang Li, Yew Von Lim, Dong Yan, Yang Shang, Bing Jian Su, Jenh Yih Juang, Qi Ge, Hui Ying Yang

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

The rational design of advanced catalysts for sodium-sulfur (Na-S) batteries is important but remains challenging due to the limited understanding of sulfur catalytic mechanisms. Here, we propose an efficient sulfur host consisting of atomic low-coordinated Zn-N2 sites dispersed on N-rich microporous graphene (Zn-N2@NG), which realizes state-of-the-art sodium-storage performance with a high sulfur content of 66 wt %, high-rate capability (467 mA h g-1 at 5 A g-1), and long cycling stability for 6500 cycles with an ultralow capacity decay rate of 0.0062% per cycle. Ex situ methods combined with theoretical calculations demonstrate the superior bidirectional catalysis of Zn-N2 sites on sulfur conversion (S8 ↔ Na2S). Furthermore, in situ transmission electron microscopy was applied to visualize the microscopic S redox evolution under the catalysis of Zn-N2 sites without liquid electrolytes. During the sodiation process, both surface S nanoparticles and S molecules in the mircopores of Zn-N2@NG quickly convert into Na2S nanograins. During the following desodiation process, only a small part of the above Na2S can be oxidized into Na2Sx. These results reveal that, without liquid electrolytes, Na2S is difficult to be decomposed even with the assistance of Zn-N2 sites. This conclusion emphasizes the critical role of liquid electrolytes in the catalytic oxidation of Na2S, which was usually ignored by previous works.

Original languageEnglish
Pages (from-to)26650-26659
Number of pages10
JournalACS Applied Materials and Interfaces
Volume15
Issue number22
DOIs
StatePublished - Jun 7 2023
Externally publishedYes

Funding

This research/project is supported by the Ministry of Education, Singapore, under its SUTD Kickstarter Initiative (SKI 2021_02_16). S. Huang gratefully acknowledges financial support from the National Natural Science Foundation of China (22109183).

FundersFunder number
Ministry of Education - SingaporeSKI 2021_02_16
National Natural Science Foundation of China22109183

    Keywords

    • Zn single atom
    • bidirectional catalysis
    • low-coordination number
    • sodium−sulfur batteries

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