Voltammetry is a powerful tool for quantifying the electrode kinetics, thermodynamic parameters, diffusivity (D), stoichiometric number of electrons (n) and bulk concentration (c) associated with an electrochemical system. In some circumstances, steady-state techniques, such as microelectrode or rotating disk electrode voltammetry, are advantageous over transient voltammetric techniques, as the steady-state limiting current, in contrast to the transient peak current, is insensitive to both sluggish heterogeneous electron-transfer kinetics and uncompensated resistance. Unfortunately, the intrinsically high viscosity of most room-temperature ionic liquids makes it difficult to approach a true voltammetric steady state, restricting the use of microelectrode and rotating disk electrode methods in these media. Another important method of voltammetric analysis involves comparing experimental and simulated transient data, and although this is versatile, it also is often hampered by uncompensated resistance and/or mechanistic uncertainties. Semiintegral voltammetry is a robust analytical method that involves transforming a transient peak-shaped voltammogram (obtained under conditions whereby mass transport occurs by semi-infinite planar diffusion) into a form which closely resembles a steady-state voltammogram. This technique shares the same advantages as the directly experimentally based steady-state techniques, but is based on data recorded under transient conditions. An extension of this technique, known generally as convolution voltammetry, allows this approach to be used under conditions where mass transport by nonplanar (radial) diffusion is significant, permitting the use of a wide range of electrode geometries and voltammetric scan rates. Overall, these convolutive techniques provide powerful analytical tools which have great versatility, being applicable in ionic liquids under conditions where the use of conventional steady-state techniques, transient peak currents, and numerical simulations to quantify D, n, or c is severely limited.
|Title of host publication||Electrochemistry in Ionic Liquids|
|Subtitle of host publication||Fundamentals|
|Editors||Angel A J Torriero|
|Place of Publication||Cham Switzerland|
|Number of pages||25|
|Publication status||Published - 2015|