Sulfur in Mesoporous Tungsten Nitride Foam Blocks: A Rational Lithium Polysulfide Confinement Experimental Design Strategy Augmented by Theoretical Predictions

Zhen Dong Huang, Yanwu Fang, Mingtong Yang, Jike Yang, Yizhou Wang, Zhen Wu, Qingchuan Du, Titus Masese, Ruiqing Liu, Xusheng Yang, Chenhui Qian, Shaowei Jin, Yanwen Ma

Research output: Journal article publicationJournal articleAcademic researchpeer-review

3 Citations (Scopus)

Abstract

To enhance the utilization of sulfur in lithium-sulfur batteries, three-dimensional tungsten nitride (WN) mesoporous foam blocks are designed to spatially localize the soluble Li2S6 and Li2S4 within the pore spaces. Meanwhile, the chemisorption behaviors of polysulfides and the capability of WN as an effective confiner are systematically investigated through density functional theory calculations and experimental studies. The theoretical calculations reveal a decrease in chemisorption strength between WN and the soluble polysulfides (Li2S8 > Li2S6 > Li2S4), while the interactions between WN and the insoluble Li2S2/Li2S show a high chemisorption strength of ca. 3 eV. Validating theoretical insights through electrochemical measurements further manifest that the assembled battery configurations with sulfur cathode confined in the thickest WN blocks exhibit the best rate capabilities (1090 and 510 mAh g-1 at 0.5C and 5C, respectively) with the highest initial Coulombic efficiency of 90.5%. Moreover, a reversible capacity of 358 mAh g-1 is maintained with a high Coulombic efficiency approaching to 100%, even after 500 cycles at 2C. As guided by in silico design, this work not only provides an effective strategy to improve the retentivity of polysulfides but also underpins that properly architectured WN can be effective retainers of polysulfides.

Original languageEnglish
Pages (from-to)20013-20021
Number of pages9
JournalACS Applied Materials and Interfaces
Volume11
Issue number22
DOIs
Publication statusPublished - 5 Jun 2019

Keywords

  • lithium polysulfides
  • lithium-sulfur batteries
  • shuttle effect
  • spatial confinement effect
  • tungsten nitride

ASJC Scopus subject areas

  • Materials Science(all)

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