Room-Temperature Ionic Liquids with High Conductivities and Wide Electrochemical Windows

Abstract

Room-temperature ionic liquids ?RTILs?, N-alkyl-N-methylpyrrolidinium (RMPyr?) and N-alkyl-N-methylpiperidinium (RMPip?) fluorohydrogenates formulated by RMPyr?HF)2.3F and RMPip?HF)2.3F(R ? ethyl, propyl, and butyl?, have been synthesized by the reactions of the corresponding chlorides and anhydrous hydrogen fluoride. These RTILs exhibit relatively low viscosities ?11.5-34.4 cP?, high conductivities ?12.3-74.6 mS cm?1?, and wide electrochemical widows around 5 V using glassy carbon electrodes. The fluorohydrogenate salts of symmetric cations, N,N-dimethylpyrrolidinium (DMPyr?) and N,N- dimethylpiperidinium (DMPip?) obtained by evacuation at room temperature are solids, exhibiting the composition of DMPyrF- 2HF and DMPipF-2HF