Lithium sulfide (Li2S)/graphene oxide nanospheres with conformal carbon coating as a high-rate, long-life cathode for Li/S cells

Yoon Hwa, Juan Zhao, Elton J. Cairns

Research output: Contribution to journalArticlepeer-review

108 Scopus citations

Abstract

In recent years, lithium/sulfur (Li/S) cells have attracted great attention as a candidate for the next generation of rechargeable batteries due to their high theoretical specific energy of 2600 W·h kg-1, which is much higher than that of Li ion cells (400-600 W·h kg-1). However, problems of the S cathode such as highly soluble intermediate species (polysulfides Li2Sn, n = 4-8) and the insulating nature of S cause poor cycle life and low utilization of S, which prevents the practical use of Li/S cells. Here, a high-rate and long-life Li/S cell is proposed, which has a cathode material with a core-shell nanostructure comprising Li2S nanospheres with an embedded graphene oxide (GO) sheet as a core material and a conformal carbon layer as a shell. The conformal carbon coating is easily obtained by a unique CVD coating process using a lab-designed rotating furnace without any repetitive steps. The Li2S/GO@C cathode exhibits a high initial discharge capacity of 650 mA·h g-1 of Li2S (corresponding to the 942 mA·h g-1 of S) and very low capacity decay rate of only 0.046% per cycle with a high Coulombic efficiency of up to 99.7% for 1500 cycles when cycled at the 2 C discharge rate.

Original languageEnglish (US)
Pages (from-to)3479-3486
Number of pages8
JournalNano Letters
Volume15
Issue number5
DOIs
StatePublished - May 13 2015
Externally publishedYes

Keywords

  • cathodes
  • energy storage
  • graphene oxide
  • lithium batteries
  • lithium sulfide
  • sulfur

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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