Direct Visualization of Lithium Polysulfides and Their Suppression in Liquid Electrolyte

Hyeon Kook Seo, Yoon Hwa, Joon Ha Chang, Jae Yeol Park, Jae Sang Lee, Jungjae Park, Elton J. Cairns, Jong Min Yuk

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Understanding of lithium polysulfide (Li-PS) formation and the shuttle phenomenon is essential for practical application of the lithium/sulfur (Li/S) cell, which has superior theoretical specific energy (2600 Wh/kg). However, it suffers from the lack of direct observation on behaviors of soluble Li-PS in liquid electrolytes. Using in situ graphene liquid cell electron microscopy, we have visualized formation and diffusion of Li-PS simultaneous with morphological and phase evolutions of sulfur nanoparticles during lithiation. We found that the morphological changes and Li-PS diffusion are retarded by ionic liquid (IL) addition into electrolyte. Chronoamperometric shuttle current measurement confirms that IL addition lowers the experimental diffusion coefficient of Li-PS by 2 orders of magnitude relative to that in IL-free electrolyte and thus suppresses the Li-PS shuttle current, which accounts for better cyclability and Coulombic efficiency of the Li/S cell. This study provides significant insights into electrolyte design to inhibit the polysulfide shuttle phenomenon.

Original languageEnglish (US)
Pages (from-to)2080-2086
Number of pages7
JournalNano Letters
Volume20
Issue number3
DOIs
StatePublished - Mar 11 2020
Externally publishedYes

Keywords

  • graphene liquid cell
  • in situ transmission electron microscopy
  • ionic liquid
  • lithium polysulfides
  • lithium sulfur cells

ASJC Scopus subject areas

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

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