Synthesis and Characterization of ( CeO2 ) 0.8 ( SmO1.5 ) 0.2 Thin Films from Polymeric Precursors

(CeO{sub 2}){sub 0.8}(SmO{sub 1.5}){sub 0.2}(CSO) has been suggested for solid oxide fuel cell (SOFC) applications, because of its higher electrical conductivity and chemical stability, compared to other ceria-based materials. However, CSO is difficult to densify under conditions compatible with other SOFC components. A thin film synthesis technique has been developed for the fabrication of dense CSO films from precursor solutions at relatively low temperatures. Dense, smooth, and homogeneous films were obtained on Pt, single-crystal Si, and La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3} (LSCF) substrates by spin-coating a polymeric precursor and subsequent heat-treatment. Crystallization of the film occurred at temperatures as low as 320 C. The developed oxide film did not react with La{sub 0.8}Sr{sub 0.2}MnO{sub 3}, LSCF, or (ZrO{sub 2}){sub 0.84}(YO{sub .15}){sub 0.16}(YSZ) at temperatures up to 1,200 C. When a CSO layer was applied between LSCF and YSZ, a significant improvement in the interfacial resistance was observed. The results suggest that CSO can be used as a buffer layer on YSZ electrolytes for improved performance of high temperature SOFCs.