Analysis of Nonexponential Transient Response Due to a Constant‐Phase Element

Abstract

To characterize electrical losses of fuel cells or batteries, impedance spectroscopy (IS) or current interruption (CI) can be used. Analysis and parameter determination of impedance data is widely used. The system under study is usually represented by an equivalent circuit from which the system parameters can be determined. However, the analysis of current‐interruption data is often carried out with too simple circuits, e.g., using pure exponential behavior, because analysis in the time domain (CI) is often much more awkward than analysis in the frequency domain (IS). A comparative study has been carried out on the analysis of a relatively ideal electrical circuit, containing a pure capacitor, and a more realistic circuit where the capacitor is replaced by a constant‐phase element. Equations describing the response in the frequency and time domain are presented. Emphasis is put upon the analysis of circuits containing a constant‐phase element because impedance measurements clearly indicate the presence of such an element in many types of experiments, and because there is only limited literature available describing the behavior in the time domain.

Obtaining electrical equivalent circuits of biological tissues using the current interruption method, circuit theory and fractional calculus

“…The current interruption method has been used in electrochemistry to estimate ohmic losses. 21 We have adapted this method for obtaining the parameter values of the EEC shown in Fig. 1(D) using a four-electrode arrangement.…”

Simulation of transient electrochemical impedance spectroscopy due to water uptake or oxide growth

“…Fringing fields, rough or fractal electrode surfaces, etc., may also contribute to this type of behavior [7]. Materials that do not have intrinsically simple exponential relaxation properties may also be modeled by CPE in an equivalent circuit [12] as well as materials that have intrinsically complex properties [13]. However, modeling with a CPE does not always prove to be satisfactory [14].…”

The differentiation of elementary polarizations of FeF3·3H2O/C cathode material in LIB

“…We usually consider the Q components as the purely capacitive components to simplify the calculation because of the difficulties in both analytical and numerical solution to the constant phase element Q and resistance R parallel in time domain. However, this approximation is only considered to be reasonable on the premise that the time constant of this parallel circuit is small enough so that the potential drop remains constant, the magnitude of which is determined by R element, after a several millisecond transient process [18]. Otherwise, the discrepancy between experimental and simulated potential transients cannot be neglected.…”