Metal-supported solid oxide fuel cells with impregnated SrFe0.75Mo0.25O3 cathodes

This paper reports on the fabrication in reducing atmospheres of SrFe0.75Mo0.25O3 (SFMO)-8 mol%Y2O3-stabilized ZrO2 (YSZ) composites by impregnating Sr2+-, Fe3+- and Mo7O246−-containing solutions into the porous YSZ backbones, which would find important applications as cathodes for co-fired metal-supported solid oxide fuel cells. X-ray diffraction examination shows that as-synthesized infiltrates consist of perovskite SFMO oxides and metallic Fe. In situ oxidation during the fuel cell operation eliminates metallic Fe, and SFMO oxides become the predominant component with some minor SrMoO4 impurities. Impedance measurements on symmetric cathode fuel cells show that such impregnated SFMO-YSZ composites exhibit low polarization resistances in air, e.g., 0.06 Ω cm2 at 800 °C. Metal-supported solid oxide fuel cells, consisting of porous 430L stainless steel substrates, Ni-YSZ active anodes, YSZ electrolytes and impregnated SFMO-YSZ composite cathodes, are fabricated using tape casting, tape lamination, co-sintering and solution impregnation techniques, and show maximum power densities of 438 mW cm−2 at 800 °C and 221 mW cm−2 at 700 °C.