Journal of the Electrochemical Society, Vol.143, No.2, 401-405, 1996
Voltammetry and Conductivity of a Polyether-Pyridinium Room-Temperature Molten-Salt Electrolyte and of Its Polymer Electrolyte-Solutions in Polydimethylsiloxane
This report describes the synthesis, microelectrode voltammetry, and ionic conductivity of a new room temperature molten salt N-(methoxy(ethoxy)(2)ethyl)pyridinium p-toluenesulfonate (abbreviated as [Py(E(3)M)(+)][Tos(-)]) and of its solution in a hydroxy-terminated polydimethylsiloxane. Both ionically conductive liquids (conductivity = 1 X 10(-4) Omega(-1) cm(-1)) exhibit voltammetric potential windows of about 1.5 V:The negative potential limit is determined by the reduction of the [Py(E(3)M)(+)] pyridinium species, with subsequent radical coupling to form a voltammetrically observed viologen dimer. The estimated diffusivities of the [Py(E(3)M)(+)] species, of a diethyleneglycol-tailed ferrocene redox solute studied, and by application of Nernst-Einstein relation to the ionic charge carriers, ail lie in the 10(-7) to 10(-8) cm(2)/s range. Viscosities and glass transition thermal observations are reported as is the fit of the temperature dependencies of ionic conductivity in [Py(E(3)M)(+)][Tos(-)] and in [Py(E(3)M)(+)] [Tos(-)]/PDMS mixtures to Vogel-Tamman-Fulcher predictions.