Free-standing compact cathodes for high volumetric and gravimetric capacity Li-S batteries

Cheng Hu, Caroline Kirk, Joaquín Silvestre-Albero, Francisco Rodríguez-Reinoso, Mark James Biggs

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Free-standing high performance Li-S battery cathodes are currently attracting significant research efforts. Loose macroporous structures have been proposed by many to improve sulfur utilization and areal capacity. However, their low cathode sulfur densities and high electrolyte fractions lead to low cell volumetric and gravimetric capacities. We report here a compact free-standing Li-S cathode structure that delivers areal, volumetric and gravimetric capacities all exceeding those of typical Li-ion batteries. The cathodes, formed by pressure filtration of the constituents, are composed of highly micro/mesoporous nitrogen-doped carbon nanospheres (NCNSs) embedded in the macropores of a multi-walled carbon nanotube (MWCNT) network to form a dense structure. The MWCNT network facilitates low cathode impedance. The NCNSs maximize sulfur utilization and immobilization. These collectively result in high cathode volumetric capacity (1106 mA h cm-3) and low electrolyte requirement (6 μL mg-1 of sulfur), which together lead to high cell-level gravimetric capacity. Stable long-term cycling at 0.3C (2.5 mA cm-2 for 5 mg cm-2 areal sulfur-loading) has also been achieved, with the areal and volumetric capacities of the best remaining above typical Li-ion values over 270 cycles and the per-cycle capacity fading being only 0.1%. The facile preparation means significant potential for large scale use.

Original languageEnglish
Pages (from-to)19924-19933
Number of pages10
JournalJournal of Materials Chemistry A
Volume5
Issue number37
Early online date25 Aug 2017
DOIs
Publication statusPublished - 7 Oct 2017

ASJC Scopus subject areas

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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    Hu, C., Kirk, C., Silvestre-Albero, J., Rodríguez-Reinoso, F., & Biggs, M. J. (2017). Free-standing compact cathodes for high volumetric and gravimetric capacity Li-S batteries. Journal of Materials Chemistry A, 5(37), 19924-19933. https://doi.org/10.1039/c7ta06781j