Li2S-reduced graphene oxide nanocomposites as cathode material for lithium sulfur batteries

Kai Han, Jingmei Shen, Cary M. Hayner, Hongqi Ye, Mayfair C. Kung, Harold H. Kung

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Abstract

A lithium sulfide-reduced graphene oxide nanocomposite (Li 2S-rGO) was synthesized and evaluated as the cathode material and Li source for the assembly of Li-S batteries. The composite, with a unique 3-D pocket structure, was synthesized by a combination of facile solution chemistry and thermal treatment. The as-prepared Li2S-rGO nanocomposites were characterized by X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy, which showed 20-40 nm Li2S particles homogeneously dispersed between reduced graphene oxide sheets. Li2S contents as high as ∼66% could be obtained. When used with an electrolyte containing LiNO3 and polysulfide, the Li2S-rGO nanocomposites exhibited a high initial capacity of 982 mAh g-1 Li2S. However, there was noticeable capacity fade in subsequent cycles, probably due to polysulfide dissolution and the shuttle mechanism, but a capacity of 315 mAh g-1 could still be obtained after 100 cycles, with 90-95% coulomb efficiency. The effect of polysulfide additive in the electrolyte on the activation of Li2S in the first delithiation step was discussed.

Original languageEnglish
Pages (from-to)331-337
Number of pages7
JournalJournal of Power Sources
Volume251
DOIs
Publication statusPublished - Apr 1 2014

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Keywords

  • Battery
  • Cathode
  • Lithium
  • Polysulfide
  • Sulfide

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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