The impact of mixtures of protic ionic liquids on the operative temperature range of use of battery systems

In this work we report for the first time about the mixture of protic ionic liquids, butylpyrrolidinium bis (trifluoromethanesulfonyl)imide (Pyr(H4)TFSI) and pyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr(HH)TFSI), as solvent for battery electrolytes. This IL mixture displays a melting point of -80 degrees C, good conductivity and low viscosity at room temperature. We show that its use together with the salt lithium bis (trifluoromethanesulfonyl)imide allows the realization of devices displaying high performance in the temperature range between -20 degrees C and 80 degrees C.