Aqueous eutectic lithium-ion electrolytes for wide-temperature operation

Hong I. Kim, Eunhye Shin, Seung Hyeok Kim, Kyung Min Lee, Jaehyun Park, Seok Ju Kang, Soonyong So, Kwang Chul Roh, Sang Kyu Kwak, Sang Young Lee

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Enabling reliable operation of energy storage devices over a wide temperature range without safety failures is an urgent prerequisite for extending their applications. Conventional liquid electrolytes in energy storage devices fail to reach this goal due to their limitations in freezing/boiling temperatures and flammability (for organic electrolytes). Here, we demonstrate a new class of aqueous eutectic electrolyte (AEE) based on a colligative property of lithium bis(trifluoromethane sulfonyl)imide (LiTFSI)-water binary mixture. The AEE (5.2 m LiTFSI in water) maximizes effect of freezing-point depression (below −40°C) and shows good electrochemical stability with electrode materials. We identify that a key-underlying mechanism of AEE is coordination of water molecules with Li+ and TFSI-. To explore potential use of AEE, we choose lithium-ion hybrid supercapacitors (HSC) as a model system. The AEE enables the HSC to provide exceptional high-rate cell performance over broad temperature ranges (−40°C ~ 100°C) without incurring fire or explosion.

Original languageEnglish
Pages (from-to)222-228
Number of pages7
JournalEnergy Storage Materials
Publication statusPublished - 2021 Apr

Bibliographical note

Funding Information:
H.-I.K. and E.S. contributed equally to this work. This work was supported by the Basic Science Research Program (2017M1A2A2087812, 2018R1A2A1A05019733, and 2018M3D1A1058624), Wearable Platform Materials Technology Center (2016R1A5A1009926) and Korean government (MSIP) (2014R1A5A1009799) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and future Planning. This work was also supported by Electronics and Telecommunications Research Institute (ETRI) grant funded by the Korea government (20ZB1200, Development of ICT Materials, Components and Equipment Technologies). Computational resources were from UNIST-HPC.

Publisher Copyright:
© 2020 Elsevier B.V.

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)
  • Energy Engineering and Power Technology


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