Determination of a Dimensionless Fluctuation Coefficient Using Electrochemical Impedance Spectroscopy

摘要

Using the Randles circuit model, we determined that, for the impedance to fall on a straight line in aCole–Cole plot, a dimensionless fluctuation coefficient that represents the quantity of the fluctuation inion concentration near an electrode must be considered. The electrochemical impedance spectroscopy(EIS) measurement in a silver ferrocyanide-thiocyanate solution containing antimony potassium tartrate(APT) known as a leveling agent fell on a straight line in a Cole–Cole plot. The dimensionless fluctuationcoefficient of silver ions, which was shown to be independent of the APT concentration, was determinedto be 8.9 by comparison with calculations of the Randles model impedance. In addition, according to thederived formulae, exchange current density and equilibrium concentration of silver ions were determined.