Polarization phenomena at the metal/proton conducting electrolyte interphase

Abstract

Abstract. The eleclxokinetics at the H 2 -Pd/SrCeo.95Ybo.0503_ct interphase are presented, Currentoverpotential (I-'q) curves were obtained at 400-700 ~ and at hydrogen partial pressures from 1 kPa to 100 kPa, using a three electrode single chamber cell. The present data were assumed to be free of mass transfer effects. The anodic and cathodic charge transfer coefficients as well as the exchange current density were calculated from the experimental results by using the Butler-Volmer equation. The high and low field approximations were used to simplify the analysis.

Electrode polarization at the Pd/proton conductor interface

“…The ohmic resistance of the solid electrolyte was calculated by taking AC impedance data. At low frequencies, the overall resistance is the sum of the ohmic resistance and electrode polarization, while at higher frequencies, it tends to become purely ohmic [12]. This high frequency value was used in each case in order to obtain ohmic-free overpotentials.…”

“…1. More details can be found in previous communications [12,13]. SEM images of the freshly prepared Pd electrodes on SCY and SZY surfaces are presented in Fig.…”

Preparation of the SrCe0.95Yb0.05O3?? proton conductor and study of the electrokinetics at the SrCe0.95Yb0.05O3??/Pd interface

“…In order to study the current-overpotential characteristics of the SCY/Pd interface, ohmic-free overpotentials had to be calculated. The ohmic resistance of the solid electrolyte was calculated by taking AC impedance data [10].…”

“…Details about the apparatus and the experimental procedure can be found in previous communications [8,10]. …”

“…Although the bulk properties of these materials have been studied by a large number of investigators [1][2][3][4], there are still details of the preparation procedure that can affect considerably their mechanical and conductivity characteristics. Furthermore, little information exists on the electrode kinetics at the electrolyte-electrode interface [5][6][7][8][9][10]. In the present study, the 5%Yb-doped strontia ceria perovskite of the form SrCe 0.95 Yb 0.05 O 3Àa (SCY) was prepared and the electrode kinetics using Pd electrodes and CO 2 -H 2 -He mixtures was studied.…”