Fundamentally manipulating the electronic structure of polar bifunctional catalysts for lithium-sulfur batteries: Heterojunction design versus doping engineering

Huifang Xu, Qingbin Jiang, Zheng Shu, Kwan San Hui, Shuo Wang, Yunshan Zheng, Xiaolu Liu, Huixian Xie, Weng Fai (Andy) Ip, Chenyang Zha, Yongqing Cai, Kwun San Hui

Research output: Contribution to journalArticlepeer-review

Abstract

Heterogeneous structures and doping strategies have been intensively used to manipulate the catalytic conversion of polysulfides to enhance reaction kinetics and suppress the shuttle effect in lithium-sulfur (Li-S) batteries. However, understanding how to select suitable strategies for engineering the electronic structure of polar catalysts is lacking. Here, a comparative investigation between heterogeneous structures and doping strategies is conducted to assess their impact on the modulation of the electronic structures and their effectiveness in catalyzing the conversion of polysulfides. These findings reveal that Co0.125Zn0.875Se, with metal-cation dopants, exhibits superior performance compared to CoSe2/ZnSe heterogeneous structures. The incorporation of low Co2+ dopants induces the subtle lattice strain in Co0.125Zn0.875Se, resulting in the increased exposure of active sites. As a result, Co0.125Zn0.875Se demonstrates enhanced electron accumulation on surface Se sites, improved charge carrier mobility, and optimized both p-band and d-band centers. The Li-S cells employing Co0.125Zn0.875Se catalyst demonstrate significantly improved capacity (1261.3 mAh g−1 at 0.5 C) and cycle stability (0.048% capacity delay rate within 1000 cycles at 2 C). This study provides valuable guidance for the modulation of the electronic structure of typical polar catalysts, serving as a design directive to tailor the catalytic activity of advanced Li-S catalysts.

Original languageEnglish
Article number2307995
JournalAdvanced Science
Early online date11 Mar 2024
DOIs
Publication statusE-pub ahead of print - 11 Mar 2024

Keywords

  • active sites
  • doping strategies
  • electronic structures
  • heterogeneous structures
  • polar catalysts

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