Enhanced Li-S batteries using amine-functionalized carbon nanotubes in the cathode

Lin Ma, Houlong Zhuang, Shuya Wei, Kenville E. Hendrickson, Mun Sek Kim, Gil Cohn, Richard G. Hennig, Lynden A. Archer

Research output: Contribution to journalArticle

197 Scopus citations

Abstract

The rechargeable lithium-sulfur (Li-S) battery is an attractive platform for high-energy, low-cost electrochemical energy storage. Practical Li-S cells are limited by several fundamental issues, including the low conductivity of sulfur and its reduction compounds with Li and the dissolution of long-chain lithium polysulfides (LiPS) into the electrolyte. We report on an approach that allows high-performance sulfur-carbon cathodes to be designed based on tethering polyethylenimine (PEI) polymers bearing large numbers of amine groups in every molecular unit to hydroxyl- and carboxyl-functionalized multiwall carbon nanotubes. Significantly, for the first time we show by means of direct dissolution kinetics measurements that the incorporation of CNT-PEI hybrids in a sulfur cathode stabilizes the cathode by both kinetic and thermodynamic processes. Composite sulfur cathodes based the CNT-PEI hybrids display high capacity at both low and high current rates, with capacity retention rates exceeding 90%. The attractive electrochemical performance of the materials is shown by means of DFT calculations and physical analysis to originate from three principal sources: (i) specific and strong interaction between sulfur species and amine groups in PEI; (ii) an interconnected conductive CNT substrate; and (iii) the combination of physical and thermal sequestration of LiPS provided by the CNT=PEI composite.

Original languageEnglish (US)
Pages (from-to)1050-1059
Number of pages10
JournalACS Nano
Volume10
Issue number1
DOIs
StatePublished - Jan 26 2016
Externally publishedYes

Keywords

  • Lithium-nitrile interactions
  • lithium-sulfur batteries
  • Molecular sorbents
  • Sequestering lithium polysulfide

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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  • Cite this

    Ma, L., Zhuang, H., Wei, S., Hendrickson, K. E., Kim, M. S., Cohn, G., Hennig, R. G., & Archer, L. A. (2016). Enhanced Li-S batteries using amine-functionalized carbon nanotubes in the cathode. ACS Nano, 10(1), 1050-1059. https://doi.org/10.1021/acsnano.5b06373