Experimental observation of ohmic impedance
By You, Chen; Dizon, Arthur; Gao, Ming; Vivier, Vincent; Orazem, Mark E.
Published in Electrochimica Acta
2022
Abstract
Impedance spectroscopy measurements are often confounded by electrode-geometry-induced high-frequency phenomena associated with a frequency-dependent complex ohmic impedance. The ohmic impedance was obtained by Levenberg-Marquardt regression of a process model that used the Havriliak-Negami equation to account for the ohmic impedance. Experimental results obtained for the ferri/ferrocyanide redox species on a gold disk used as a model system were interpreted using a physical description expressed in terms of an ohmic impedance and an expression that accounted for the influence of a local constant-phase element on the faradaic reaction and the convective diffusion impedance. Regressions were weighted by the experimentally determined error structure of the data, and the resulting parameters characteristic of the ohmic impedance were in excellent agreement with numerical simulations.