Fabrication and characterization of micro-tubular cathode-supported SOFC for intermediate temperature operation

We report the fabrication and characterization of a micro-tubular cathode-supported cell consisting of a Ce0.9Gd0.1O1.95 electrolyte with a Ni–cermet anode on a porous La0.6Sr0.4Co0.2Fe0.8O3−δ/Ce0.9Gd0.1O1.95 (60:40 volume) tube (460 μm wall thickness and 2.26 mm diameter). The cells were fabricated by a cost-effective technique involving extrusion molding and slurry coating through a co-firing process. Densification of the ceria film (thickness < 15 μm) was successful by co-firing the laminated electrolyte with the porous cathode at 1200 °C. NiO–Ce0.9Gd0.1O1.95 (Ni: Ce0.9Gd0.1O1.95 = 50:50 in volume after reduction) was subsequently sintered on the electrolyte at 1100 °C to construct a 10 μm thick, porous and well-adherent anode. The cell having 1.5 cm tube length fed with humidified 30 vol.% H2–Ar (3% H2O) yielded the maximum power densities of 0.16, 0.13 and 0.11 W cm−2, at 600, 550 and 500 °C, respectively. It was found that the cell performance is strongly dominated by the tube length, due to a high substrate resistance from the cathode current collections.