Durability test on coral Ce0.9Gd0.1O2-δ-La0.6Sr0.4Co0.2Fe0.8O3-δ with La0.6Sr0.4Co0.2Fe0.8O3-δ current collector working in SOFC and SOEC modes

Abstract

This work presents a 790h durability test performed on a solid oxide cell. An innovative Ce0.9Gd0.1O2-δ-La0.6Sr0.4Co0.2Fe0.8O3-δ oxygen electrode with coral microstructure was deposited on a solid oxide fuel cell (SOFC) anode supported with 8mol.% yttria-stabilized zirconia (8YSZ) electrolyte. An initial cell potential was found to be 817mV at 773 °C under synthetic air on the oxygen electrode side, and pure hydrogen (500NmL.min−1) on the hydrogen electrode side, under 0.5A.cm−2 current density in SOFC. The initial cell potential in the solid oxide electrolysis cell (SOEC) was 1200mV at 773°C under synthetic air on the oxygen electrode side and a mixture of steam/hydrogen (80 %/20 %, respectively) on the hydrogen electrode side under −0.75 and −0.5 A.cm−2 current density. The cell resistance progressively increased during the durability test. The increase at the high frequency range was mainly responsible for an increase in total cell resistance. This frequency range was associated with the blocking effect on the oxygen electrode/electrolyte interface. U-j curves showed reversibility of the current loading from −0.75 to 0.5A.cm−2. SEM observations indicated cracks in the 8YSZ electrolyte and the detachment of the oxygen electrode.