Cell performance of strontium ruthenium oxide cathode/ Gd-doped ceria (GDC) electrolyte/ nickel-GDC anode system

Abstract

Cell performance was measured at 773-1073 K for Ni-GDC(Gd-doped ceria) anode-supported GDC film (60 μm thickness) with SrRuO3 cathode using a 3 vol% H2O-containing H2 fuel. Reduction of particle size (< 1 μm) of SrRuO3 cathode was effective to decrease the voltage drop at the cathode because of the increased length of triple phase boundary (GDC electrolyte-SrRuO3 cathode-O2 gas). Open circuit voltage (OCV) of GDC electrolyte in an anode atmosphere without H2 fuel was close to the value calculated by Nernst equation for no electronic conduction. However, the OCV in a H2-containing atmosphere decreased from the values by Nernst equation owing to the increased electronic conduction in a GDC film. This tendency of decrease in OCV became significant for thinner GDC film. This result was interpreted by the dissolution and dissociation of H2 fuel in a GDC film to form protons and electrons (H2 → 2H+ + 2e-).