Electrochemical Characterization of Ceramic SOFC Anodes

Abstract

A simple method for the rapid electrochemical characterization of solid oxide fuel cell (SOFC) anodes is presented. Current-potential and impedance measurements have been performed at operating temperature in a simplified manner using unsintered ceramic electrodes. Results for materials with different crystal structures and electrical properties are presented and show characteristic differences attributed to the materials’ electrical properties. At 1000°C in hydrogen saturated with water at room temperature materials with dominant electronic conduction show polarization resistances in the range 10-13 Ω cm2.cm2. For mixed conducting ceramics as Y0.2Ti0.18Zr0.62O1.9±δY0.2Ti0.18Zr0.62O1.9±δ (YZT) and Ce0.6Gd0.4O2±δCe0.6Gd0.4O2±δ the electrochemical performance is improved to 3.7 and 0.44 Ω cm2,cm2, respectively. The best value measured for YZT was 0.7 Ω cm2cm2 when sintering the layer at 1300°C. Initial evaluation of the impedance spectra indicates an extension of the reaction zone into the porous mixed conducting electrode, which can explain the higher electrochemical activity of the mixed conductors Ce0.6Gd0.4O1.8±δCe0.6Gd0.4O1.8±δ and YZT. © 2001 The Electrochemical Society. All rights reserved.