biostudies-literatureKisu KJapan Society for the Promotion of Science7563https://www.ebi.ac.uk/biostudies/studies/S-EPMC8024376biostudies-literatureUnknown11(1)High-energy-density and low-cost calcium (Ca) batteries have been proposed as 'beyond-Li-ion' electrochemical energy storage devices. However, they have seen limited progress due to challenges associated with developing electrolytes showing reductive/oxidative stabilities and high ionic conductivities. This paper describes a calcium monocarborane cluster salt in a mixed solvent as a Ca-battery electrolyte with high anodic stability (up to 4 V vs. Ca²⁺/Ca), high ionic conductivity (4 mS cm^-1), and high Coulombic efficiency for Ca plating/stripping at room temperature. The developed electrolyte is a promising candidate for use in room-temperature rechargeable Ca batteries.Scientific reportsMonocarborane cluster as a stable fluorine-free calcium battery electrolyte.PMC802437618H0551319K15305Kim SKisu KZuttel AShinohara TZhao KOrimo SIfalseMonocarborane cluster as a stable fluorine-free calcium battery electrolyte.High-energy-density and low-cost calcium (Ca) batteries have been proposed as 'beyond-Li-ion' electrochemical energy storage devices. However, they have seen limited progress due to challenges associated with developing electrolytes showing reductive/oxidative stabilities and high ionic conductivities. This paper describes a calcium monocarborane cluster salt in a mixed solvent as a Ca-battery electrolyte with high anodic stability (up to 4 V vs. Ca²⁺/Ca), high ionic conductivity (4 mS cm^-1), and high Coulombic efficiency for Ca plating/stripping at room temperature. The developed electrolyte is a promising candidate for use in room-temperature rechargeable Ca batteries.2021-01-01T00:00:00Z2021 Apr2025-04-19T16:15:44.48Z2022-02-09T14:16:13.228ZS-EPMC80243763382435710.1038/s41598-021-86938-0