Correction of chaotic distortions in electrochemical impedance spectra

Abstract

The work is dedicated to the problem of minimization of the effect of industrial noise on electrochemical impedance. A method of moving chaotic points on the impedance curve into new positions on the complex plane is developed. Coordinates of these positions were determined using reproducible impedance measurements at two close frequencies (ω₁ and ω₂). A physically validated sample model representing a resistor–capacitor bipole was used as the basis for approximation of impedance for frequency (ω₃), where chaos is observed. It is shown that this equivalent circuit in the absence of the inductive impedance component adequately describes electric properties of the sample in the frequency range of at least half a decade. Detailed derivation of all relationships required for calculation of impedance at frequency ω₃ is provided. The developed algorithm can be used for implementation of a digital filter that allows correcting the impedance spectrum in the automatic mode. The suggested method is used to correct the impedance spectrum of Bi_1.6Cu_0.8Ti₂O_7.2 solid solution distorted by electromagnetic interference.