Impedance spectroscopy studies of electrode-electrolyte systems
Abstract Impedance spectra have been recorded for three different electrode systems (Pt, Pt/SrCeO 3 : Yb and Pt/CaTiO 3 ) with ZrO 2 :8Y 2 O 3 as a common electrolyte. The systems have been investigated as a function of temperature (650–875°C) and oxygen partial pressure (10 −5 −1 atm). The measured impedance spectra have been deconvoluted by means of an NLLS program and are well described by a Randles type equivalent circuit, in which the electrode resistance is the sum of a charge transfer resistance and a diffusion resistance. The cathodic reaction is apparently limiting in all three systems. In all three systems the presence of a PtO x compound is suggested.