The performances of anode-supported solid oxide fuel cells (SOFCs) utilizing a Mn-containing ferritic stainless steel (Crofer22 APU) as the cathode current collector were assessed. Three cathodes were considered: (La0.8Sr0.2)(0.99)MnO3, (La0.8Sr0.2)(0.99)FeO3, and (La0.6Sr0.4)(0.98)Fe0.8Co0.2O3 (all samples incorporated a Sm-doped CeO2 interlayer between the cathode and the thin-film yttria-stablized zirconia electrolyte). Inclusion of the Fe-Cr alloy caused rapid degradation in all samples, which was attributed to solid-state reactivity at the cathode-Crofer interface, in addition to Cr volatilization from the alloy and subsequent condensation/ reaction within the cathode and at the cathode-electrolyte interface. In situ high-temperature X-ray diffraction was used to assess the cathode-Crofer reaction products. Preoxidation of the Crofer at 800 degrees C for 500 h to form a protective (Mn, Cr)(3)O-4 spinel coating resulted in a marginal reduction of the cell degradation rate. (c) 2005 The Electrochemical Society.