Application of the Positive Reality Principle to Metal Electrode Linear Polarization Phenomena

The linear electrode-electrolyte polarization immittance (impedance or admittance) can be analyzed by the fractional power pole (FPP) model [38] based on the modification of Bode's [4] method to include functions with poles and/or zeros of fractional power. This is, in essence, an extension of the Davidson-Cole model [12] to the entire frequency spectrum. In this paper, the minimum phase property of the FPP model is verified and the positive reality principle [5] is used to identify the specific type of immittance function for which the FPP model is applicable. This condition is an extension of the "universal" law of dielectric response as advanced by Jonscher [26].     

A Unified Approach to Represent Metal Electrode Polarization

A unifying approach based on methods of linear and nonlinear systems engineering theory to conveniently analyze the metal electrode polarization is presented. The polarization phenomenon is modeled in the linear and nonlinear range. The linear model is based on an exentension of Bode's method consisting of a number of time constant distributions of the Davidson?Cole type. In the nonlinear range, the describing function method is used to analyze the interface in terms of a modified saturation element in cascade with a linear part. The linear part of the nonlinear model has the same form as the linear model with shorter "apparent" average time constants than the corresponding linear representation. The applicability of the method is illustrated using the platinum electrode data. However, the methodology is equally appropriate to the study of a wide class of interfacial and dielectric polarization phenomena characterized by a special dispersion behavior.