LAUSR

Redox-active ionic liquids are of interest for various applications in electrochemistry, for example, as electrochemically active anions and cations in supercapacitors, as redox mediators in dye-sensistized solar cells and for overcharge protection in batteries. Due to the chemical variability of redox-active ionic liquids, their electrochemical properties can be easily tuned. Here, we investigate the electrochemical kinetic properties of four ionic liquids containing sulfonium and phosphonium cations, with ferrocenyl substituents directly attached to the onium center. The redox-active ionic liquids are dissolved in the electrochemically innocent ionic liquid [EMIm]TFSI. The results are compared to the electrochemical kinetic properties of free ferrocene standard. We obtain precise values for the heterogeneous rate constant k0 by means of a multispectrum fit of impedance spectra measured at different overpotentials. Diffusion coefficients are derived from a convolution analysis of cylic voltammograms. The...