Fabrication of thin Ag–YSB composite cathode film for intermediate-temperature solid oxide fuel cells

Composites consisting of Ag–Y0.25Bi0.75O1.5 (YSB) were investigated as composite cathodes for intermediate-solid oxide fuel cells. A thin film of Ag–YSB composite cathode was fabricated by using slurry painting method. The slurry of Ag–YSB composite cathodes was used to coat anode-bilayered electrolytes (NiO–SDC/SDC/YSB) at room temperature. TGA and DSC results confirmed that all the organic components in the slurry were completely decomposed at temperatures below 600 °C. XRD analysis revealed the formation of a pure Ag–YSB composite cathode phase. SEM images showed the grain size increment of the Ag–YSB powder that was ascribed to the consolidation between adjacent grains, which reduced the size of the porosity as the heat treatment temperature was increased. The electrochemical performances (interfacial polarization resistance, Rp) were 0.483, 0.469, 0.416, and 0.441 Ω cm2 after one, two, three, and four coatings, respectively.