Insight to the synergistic effect of N-doping level and pore structure on improving the electrochemical performance of sulfur/N-doped porous carbon cathode for Li-S batteries

Shanxing Wang, Kaixiang Zou, Yunxian Qian, Yuanfu Deng, Lei Zhang, Guohua Chen

Research output: Journal article publicationJournal articleAcademic researchpeer-review

31 Citations (Scopus)

Abstract

Three nitrogen-doped porous carbons (NDPCs) with the ultrahigh specific surface areas are prepared via a one-step activation of the biomass waste. The as-prepared samples have different levels of nitrogen contents and pore structure. These sulfur hosting matrix materials are designed to systematically elaborate the effect of N-doping level and pore structure on the electrochemical performance of the S/NDPC nanocomposites. The higher volume ratio of marco-mesopores to micropores of the substrate can greatly enhance the rate capability of the S/NDPC cathodes. This is attributed to the improved electrolyte penetration via the rich marco-mesopores. Meanwhile, the higher nitrogen content of the NDPC contributes to improving the cycle stability of the S/NDPC cathode, which is assigned to the strong chemical adsorption and physical restriction of polysulfides by the interaction of nitrogen atom and polysulfides. Therefore, the S/NDPC-1 cathode, prepared by using a NDPC matrix with high nitrogen content, large specific surface area, and a moderate microporous volume percentage (V Micro /V T ), displays an obvious enhancement in the electrochemical performance. It exhibits specific capacities of 926.1 and 815.8 mAh g −1 at 0.5 and 1.0 C rate, respectively, with a capacity fading rate of only 0.067% per cycle after 500 cycles at 1.0 C.

Original languageEnglish
Pages (from-to)745-755
Number of pages11
JournalCarbon
Volume144
DOIs
Publication statusPublished - 1 Apr 2019

Keywords

  • Electrochemical performance
  • Li-S batteries
  • N-doped carbon
  • Pore structure
  • Synergistic effect

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)

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