Four room-temperature ionic liquids (RTILs) based on N-methyl-N-methoxyethylpyrrolidinium (PYR1201+) and fluorinated sulfonylimides, bis(fluorosulfonyl)imide (FSI-), bis(trifluoromethanesulfonyl)imide (TESI-),bis(pentafluoroethylsulfonyl)imide (BETI-) and (trifluoromethanesulfonyl) (nonafluorobutanesulfonyl)imide (IM14-) anion have been synthesised and intensively investigated from an electrochemical and physico-chemical point of view, including thermal behaviour, viscosity, conductivity and electrochemical stability. The prepared ionic liquids are thermally stable (over 200 degrees C in N-2 and over 180 degrees C in O-2 atmosphere) and electrochemically stable with electrochemical stability windows on platinum in the range from 4.7 V (PYR1201FSI) to 5.4V (PYR1201IM14). Conductivity decreases in the series FSI-TESI-BETI-IM14 according to the viscosity increase. DSC measurements showed no crystallisation down to -150 degrees C for PYR1201TESI and PYR1201 IM14. (C) 2012 Elsevier Ltd. All rights reserved.