High Crystallinity 2D π–d Conjugated Conductive Metal–Organic Framework for Boosting Polysulfide Conversion in Lithium–Sulfur Batteries

Tong Guo, Yichen Ding, Chang Xu, Wuxin Bai, Shencheng Pan, Mingliang Liu, Min Bi, Jingwen Sun, Xiaoping Ouyang, Xin Wang, Yongsheng Fu, Junwu Zhu

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The catalytic performance of metal–organic frameworks (MOFs) in Li-S batteries is significantly hindered by unsuitable pore size, low conductivity, and large steric contact hindrance between the catalytic site and lithium polysulfide (LPSs). Herein, the smallest π-conjugated hexaaminobenzene (HAB) as linker and Ni(II) ions as skeletal node are in situ assembled into high crystallinity Ni-HAB 2D conductive MOFs with dense Ni-N4 units via dsp2 hybridization on the surface of carbon nanotube (CNT), fabricating Ni-HAB@CNT as separator modified layer in Li-S batteries. As-obtained unique π-d conjugated Ni-HAB nanostructure features ordered micropores with suitable pore size (≈8 Å) induced by HAB ligands, which can cooperate with dense Ni-N4 chemisorption sites to effectively suppress the shuttle effect. Meanwhile, the conversion kinetics of LPSs is significantly accelerated owing to the small steric contact hindrance and increased delocalized electron density endued by the planar tetracoordinate structure. Consequently, the Li-S battery with Ni-HAB@CNT modified separator achieves an areal capacity of 6.29 mAh cm−2 at high sulfur loading of 6.5 mg cm−2 under electrolyte/sulfur ratio of 5 µL mg−1. Moreover, Li-S single-electrode pouch cells with modified separators deliver a high reversible capacity of 791 mAh g−1 after 50 cycles at 0.1 C with electrolyte/sulfur ratio of 6 µL mg−1.

Original languageEnglish
Article number2302518
JournalAdvanced Science
Volume10
Issue number27
DOIs
StatePublished - 26 Sep 2023
Externally publishedYes

Keywords

  • conductive metal–organic frameworks
  • functionalized separator
  • lithium–sulfur batteries
  • polysulfides

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • General Chemical Engineering
  • General Materials Science
  • Biochemistry, Genetics and Molecular Biology (miscellaneous)
  • General Engineering
  • General Physics and Astronomy

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