Low-viscosity quaternary ammonium-based ionic liquid electrolytes for lithium air batteries

Hyunjee Yoon, Seoyoon Shin, Sooyeol Park, Moo Whan Shin

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Ionic liquids (ILs) have attracted significant attention as candidates for Li-air battery electrolyte solvents owing to their novel properties, such as non-volatility and low reactivity with lithium metal anodes. However, the main drawback of IL-based electrolytes is their high viscosity, which results in poor battery capacity and conductivity. In this study, we synthesized low-viscosity ILs with reduced molecular weights using the side-chain shortening method. In particular, the IL: trimethyl ethoxymethyl ammonium bis(fluoromethylsulfonyl)imide (N111(1O2) FSI), has a lower viscosity (111.4 cP) than that of the electrochemically stable reference material, diethylmethyl (2-methoxyethyl) ammonium bis(fluoromethylsulfonyl)imide (DEME FSI; viscosity of 131.1cP). The use of the optimal IL, N111(1O2) FSI, resulted in an initial capacity 3.75 times higher than that obtained using DEME FSI in the cell test. The chemical stability of N111(1O2) FSI with lithium metal was confirmed by microstructure analysis of the lithium surface. The physicochemical properties, such as viscosity, ionic conductivity, melting point, and electrochemical properties, were thoroughly characterized.

Original languageEnglish
Article number119352
JournalJournal of Molecular Liquids
Publication statusPublished - 2022 Aug 1

Bibliographical note

Funding Information:
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: MooWhan Shin reports financial support was provided by Hyundai Motor Company.

Publisher Copyright:
© 2022 Elsevier B.V.

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Spectroscopy
  • Physical and Theoretical Chemistry
  • Materials Chemistry


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