Enlarged electrochemical window in dialkyl-imidazolium cation based room-temperature air and water-stable molten salts

The electrochemical windows of the ionic liquids 1-n-butyl-3-methyl imidazolium tetrafluoroborate (BMI+)(BF4−) and 1-butyl-3-methyl imidazolium hexafluorophosphate (BMI+)(PF6−) have been investigated at platinum, vitreous carbon, tungsten and gold electrodes. The lowest current densities and widest electrochemical windows were found on tungsten and vitreous carbon 6.10 and 5.45 V for (BMI+)(BF4−) and >7.10 and 6.35 V for (BMI+)(PF6−), respectively.