Strong Chemical Interaction between Lithium Polysulfides and Flame-Retardant Polyphosphazene for Lithium–Sulfur Batteries with Enhanced Safety and Electrochemical Performance

Peng Chen, Zhen Wu, Tong Guo, Yan Zhou, Mingliang Liu, Xifeng Xia, Jingwen Sun, Lude Lu, Xiaoping Ouyang, Xin Wang, Yongsheng Fu, Junwu Zhu

Research output: Contribution to journalArticlepeer-review

118 Scopus citations

Abstract

The shuttle effect of lithium polysulfides (LiPS) and potential safety hazard caused by the burning of flammable organic electrolytes, sulfur cathode, and lithium anode seriously limit the practical application of lithium–sulfur (Li–S) batteries. Here, a flame-retardant polyphosphazene (PPZ) covalently modified holey graphene/carbonized cellulose paper is reported as a multifunctional interlayer in Li–S batteries. During the discharge/charge process, once the LiPS are generated, the as-obtained flame-retardant interlayer traps them immediately through the nucleophilic substitution reaction between PPZ and LiPS, effectively inhibiting the shuttling effect of LiPS to enhance the cycle stability of Li–S batteries. Meanwhile, this strong chemical interaction increases the diffusion coefficient for lithium ions, accelerating the lithiation reaction with complete inversion. Moreover, the as-obtained interlayer can be used as a fresh 3D current collector to establish a flame-retardant “vice-electrode,” which can trap dissolved sulfur and absorb a large amount of electrolyte, prominently bringing down the flammability of the sulfur cathode and electrolyte to improve the safety of Li–S batteries. This work provides a viable strategy for using PPZ-based materials as strong chemical scavengers for LiPS and a flame-retardant interlayer toward next-generation Li–S batteries with enhanced safety and electrochemical performance.

Original languageEnglish
Article number2007549
JournalAdvanced Materials
Volume33
Issue number9
DOIs
StatePublished - 1 Mar 2021
Externally publishedYes

Keywords

  • flame-retardant
  • lithium–sulfur batteries
  • polyphosphazene
  • safety
  • strong chemical interaction

ASJC Scopus subject areas

  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering

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