Carbonaceous-Material-Induced Gelation of Concentrated Electrolyte Solutions for Application in Lithium-Sulfur Battery Cathodes

Ryo Motoyoshi, Shanglin Li, Seiji Tsuzuki, Arnab Ghosh, Kazuhide Ueno, Kaoru Dokko, Masayoshi Watanabe

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Lithium-sulfur (Li-S) batteries can theoretically deliver high energy densities exceeding 2500 Wh kg-1. However, high sulfur loading and lean electrolyte conditions are two major requirements to enhance the actual energy density of the Li-S batteries. Herein, the use of carbon-dispersed highly concentrated electrolyte (HCE) gels with sparingly solvating characteristics as sulfur hosts in Li-S batteries is proposed as a unique approach to construct continuous electron-transport and ion-conduction paths in sulfur cathodes as well as achieve high energy density under lean-electrolyte conditions. The sol-gel behavior of carbon-dispersed sulfolane-based HCEs was investigated using phase diagrams. The sol-to-gel transition was mainly dependent on the amount of the carbonaceous material and the Li salt content. The gelation was caused by the carbonaceous-material-induced formation of an integrated network. Density functional theory (DFT) calculations revealed that the strong cation-πinteractions between Li+and the induced dipole of graphitic carbon were responsible for facilitating the dispersion of the carbonaceous material into the HCEs, thereby permitting gel formation at high Li-salt concentrations. The as-prepared carbon-dispersed sulfolane-based composite gels were employed as efficient sulfur hosts in Li-S batteries. The use of gel-type sulfur hosts eliminates the requirement for excess electrolytes and thus facilitates the practical realization of Li-S batteries under lean-electrolyte conditions. A Li-S pouch cell that achieved a high cell-energy density (up to 253 Wh kg-1) at a high sulfur loading (4.1 mg cm-2) and low electrolyte/sulfur ratio (4.2 μL mg-1) was developed. Furthermore, a Li-S polymer battery was fabricated by combining the composite gel cathode and a polymer gel electrolyte.

Original languageEnglish
Pages (from-to)45403-45413
Number of pages11
JournalACS applied materials & interfaces
Volume14
Issue number40
DOIs
StatePublished - 12 Oct 2022
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.

Funding

This study was supported by Japan Science and Technology Agency (JST) ALCA-SPRING (Grant JPMJAL1301), Japan.

FundersFunder number
Japan Science and Technology AgencyJPMJAL1301

    Keywords

    • Li-S battery
    • carbonaceous material
    • cation-πinteraction
    • high energy density
    • highly concentrated electrolyte
    • polymer gel cathode
    • sol-gel transition

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