An advanced ionic liquid-lithium salt electrolyte mixture based on the bis(fluoromethanesulfonyl)imide anion

•A novel PYR24FSI-LiFSI mixture was prepared.•The mixture melts near − 40 °C with a room temperature conductivity close to 4 × 10− 3 S cm− 1.•The PYR24FSI-LiFSI mixture is an appealing electrolyte for lithium battery systems.

An innovative electrolyte mixture, based on the novel N-butyl-N-ethylpyrrolidinium bis(fluoromethanesulfonyl)imide (PYR24FSI) ionic liquid and the LiFSI lithium salt, was prepared and its thermal and ion-transport properties were investigated. The FSI-based mixture showed fast crystallization kinetics with melting point around − 40 °C. A conductivity close to 4 × 10− 3 S cm− 1 was reached at room temperature. This PYR24FSI-LiFSI mixture family has been found to be an appealing electrolyte for high safety and performance lithium battery systems.

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