Allylic ionic liquid electrolyte-assisted electrochemical surface passivation of LiCoO2 for advanced, safe lithium-ion batteries

Junyoung Mun, Taeeun Yim, Jang Hoon Park, Ji Heon Ryu, Sang Young Lee, Young Gyu Kim, Seung M. Oh

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)


Room-temperature ionic liquid (RTIL) electrolytes have attracted much attention for use in advanced, safe lithium-ion batteries (LIB) owing to their nonvolatility, high conductivity, and great thermal stability. However, LIBs containing RTIL-electrolytes exhibit poor cyclability because electrochemical side reactions cause problematic surface failures of the cathode. Here, we demonstrate that a thin, homogeneous surface film, which is electrochemically generated on LiCoO2 from an RTIL-electrolyte containing an unsaturated substituent on the cation (1-allyl-1-methylpiperidinium bis(trifluoromethanesulfonyl)imide, AMPip-TFSI), can avert undesired side reactions. The derived surface film comprised of a high amount of organic species from the RTIL cations homogenously covered LiCoO2 with a ,25 nm layer and helped suppress unfavorable thermal reactions as well as electrochemical side reactions. The superior performance of the cell containing the AMPip-TFSI electrolyte was further elucidated by surface, electrochemical, and thermal analyses.

Original languageEnglish
Article number5802
JournalScientific reports
Publication statusPublished - 2014 Aug 29

Bibliographical note

Funding Information:
The authors acknowledge the financial support from the National Research Foundation of Korea funded by the MEST (NRF-2010-C1AAA001-2010-0029065).

All Science Journal Classification (ASJC) codes

  • General


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