Fluorinated, Sulfur-Rich, Covalent Triazine Frameworks for Enhanced Confinement of Polysulfides in Lithium-Sulfur Batteries

Fei Xu, Shuhao Yang, Guangshen Jiang, Qian Ye, Bingqing Wei, Hongqiang Wang

Research output: Contribution to journalArticlepeer-review

167 Scopus citations

Abstract

Lithium-sulfur battery represents a promising class of energy storage technology owing to its high theoretical energy density and low cost. However, the insulating nature, shuttling of soluble polysulfides and volumetric expansion of sulfur electrodes seriously give rise to the rapid capacity fading and low utilization. In this work, these issues are significantly alleviated by both physically and chemically restricting sulfur species in fluorinated porous triazine-based frameworks (FCTF-S). One-step trimerization of perfluorinated aromatic nitrile monomers with elemental sulfur allows the simultaneous formation of fluorinated triazine-based frameworks, covalent attachment of sulfur and its homogeneous distribution within the pores. The incorporation of electronegative fluorine in frameworks provides a strong anchoring effect to suppress the dissolution and accelerate the conversion of polysulfides. Together with covalent chemical binding and physical nanopore-confinement effects, the FCTF-S demonstrates superior electrochemical performances, as compared to those of the sulfur-rich covalent triazine-based framework without fluorine (CTF-S) and porous carbon delivering only physical confinement. Our approach demonstrates the potential of regulating lithium-sulfur battery performances at a molecular scale promoted by the porous organic polymers with a flexible design.

Original languageEnglish
Pages (from-to)37731-37738
Number of pages8
JournalACS Applied Materials and Interfaces
Volume9
Issue number43
DOIs
StatePublished - 1 Nov 2017

Keywords

  • covalent triazine frameworks
  • fluorinated
  • lithium-sulfur batteries
  • polysulfides confinement
  • porous organic polymers
  • trimerization

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