Influence of Composition of Gd-Doped Ceria Electrolyte on Performance of Solid Oxide Fuel Cell

Abstract

Cell performance was measured for four types of Ni (40 vol%)-Gd-doped ceria (GDC) anode-supported solid oxide fuel cells with GDC electrolyte (40-120 μm thickness) of Ce1-xGdxO2-x/2 compositions (x = 0.05, 0.1, 0.15 and 0.2) at 773-1073 K using a H2 fuel. (La0.8Sr0.2)(Co0.8Fe0.2)O3 cathode was printed on the GDC films. The open circuit voltage and maximum power density at 873-1073 K showed a maximum at x = 0.1. The maximum power density at x = 0.1 was 166 and 506 mW/cm2 at 873 and 1073 K, respectively. The excess oxygen vacancy at x = 0.1-0.2, which does not contribute to the oxide ion conductivity, reacts with a H2 fuel to form electrons (H2 + VO 2H+ + VO×, VO× VO + 2e-). This reaction reduces the cell performance.