Fitting Improvement Using a New Electrical Circuit Model for the Electrode-Electrolyte Interface

The characteristics of impedance for the electrode-electrolyte interface are important in the electrode researches for biomedical applications. So, the equivalent circuit models for the interface have been researched and developed. However, the applications of such previous models are limited in terms of the frequency range, type of electrode or electrolyte. In this paper, a new electrical circuit model was proposed and demonstrated its capability of fitting the experimental results more accurately than before. A new electrical circuit model consists of three resistors and two constant phase elements. Electrochemical impedance spectroscopy was used to characterize the interface for several materials of Au, Pt, and stainless steel electrode in 0.9% NaCl solution. The new model and the previous model were applied to fit the measured impedance results, and were compared their goodness of fit