Performance of a Double-Layer CGO/YSZ Electrolyte for Solid Oxide Fuel Cells

The use of a double-layer ceria-gadolinia (CGO) - yttria-stabilized zirconia (YSZ) electrolyte has been suggested as an alternative for efficient intermediate temperature operation of Solid Oxide Fuel Cells (SOFC). CGO offers the advantage of high ionic conductivity and good chemical compatibility with Co-containing cathode perovskite materials, while YSZ serves as an electron blocking layer. The main problem for the applicability of such a composite film still remains the formation of a poorly conductive solid solution phase at the CGO/YSZ interface. The microstructure and the elemental distribution of this solid solution phase were examined with the aid of electronic probe microanalysis. Powders with the same composition were synthesized in order to examine their crystal structure and electrical properties, with the objective to propose a suitable gradation at the interface in order to improve the feasibility of CGO/YSZ two-layer composite electrolyte films.