Demixing the miscible liquids: toward biphasic battery electrolytes based on the kosmotropic effect

Won Yeong Kim, Hong I. Kim, Kyung Min Lee, Eunhye Shin, Xu Liu, Hyunseok Moon, Henry Adenusi, Stefano Passerini, Sang Kyu Kwak, Sang Young Lee

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Exploring new electrolyte chemistry beyond conventional single-phase battery electrolytes is needed to fulfill the heterogeneous requirements of anodes and cathodes. Here, we report a biphasic liquid electrolyte (BLE) based on the kosmotropic effect. The key underlying technology for the BLE is phase separation of its electrolyte couples using a principle of “demixing the miscible liquids”. Kosmotropic/chaotropic anions affect the ion coordination structures and the intermolecular interactions of electrolyte couples, enabling on-demand control of their immiscibility/miscibility. Despite the intrinsic miscibility of water (in aqueous electrolytes) and acetonitrile (in nonaqueous electrolytes), the structural change of the aqueous electrolyte induced by kosmotropic anions allows demixing with the nonaqueous electrolyte. The resultant BLE facilitates redox kinetics at cathodes and Zn plating/stripping cyclability at anodes. Consequently, the BLE enables Zn-metal full cells to exhibit a long cyclability (86.6% retention after 3500 cycles). Moreover, Zn anode-free full cells with the BLE exhibit a higher energy density (183 W h kg−1) than previously reported Zn batteries.

Original languageEnglish
Pages (from-to)5217-5228
Number of pages12
JournalEnergy and Environmental Science
Issue number12
Publication statusPublished - 2022 Oct 12

Bibliographical note

Funding Information:
This work was supported by the Basic Science Research Program (2021R1A2B5B03001615, 2021M3D1A2043791, and 2020R1A2C3005939) through the National Research Foundation of Korea (NRF) grant by the Korean Government (MSIT). This work was also supported by the LG energy solution. Computational resources were supported by the National Supercomputing Center including technical support (KSC-2020-CRE-0340) and UNIST-HPC.

Publisher Copyright:
© 2022 The Royal Society of Chemistry.

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Pollution


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