Enhanced electrochemical stability of polyaniline in ionic liquids

The electrochemical performance of polyaniline thin films on platinum electrode substrates has been investigated using cyclic voltammetry in two aprotic ionic liquid electrolyte systems, 1-butyl-3-methyl imidazolium hexafluorophosphate (BMI PF(6)(-)) or 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfon)imide (EMI TFSI). Enhanced redox stability of the polyaniline was observed in both electrolyte systems. Initial redox cycles in both ILs exhibited increasing current responses, over the first 10-20 cycles, which was attributed to the electrochemically induced ion exchange processes occurring within polyaniline film. Extended cycling after the redoping process was observed to result in a stable and reversible electrochemistry. (C) 2003 Elsevier B.V. All rights reserved.