Evaluation of Chemical Stability in Perovskite-Type Proton-Conductive Oxide Thin-Films

The chemical stability of sputtered Ba(Ce,Y)O-3, Ba(Zr,Y)O-3, and Sr(Zr,Y)O-3 thin-films of proton-conductive oxides were investigated. The samples were prepared under optimal conditions regarding crystallinity and annealed at 600 degrees C for 12 h in wet Ar atmosphere. The annealed samples were characterized by XRD measurement. Although the Ba(Ce,Y)O-3 thin-film after annealed in wet Ar atmosphere was decomposed to Ba(OH)(2) and CeO2, Ba(Zr,Y)O-3 and Sr(Zr,Y)O-3 thin-films showed high chemical stability. Higher chemical stability materials are desired for applying an electrolyte of fuel cells; however, a material which satisfies sufficient proton conductivity and chemical stability were hardly reported. Thus, we propose a novel structure of Ba (Ce,Y)O-3 with fully covered by Ba(Zr,Y)O-3 of high chemical stability as a protection layer. As a results of endurance test of chemical stability for 100 h in wet Ar atmosphere, no degradation or decomposition of Ba(Zr,Y)O-3/Ba(Ce,Y)O-3 was observed. Thus, these multilayer structures can be candidate for improvement of chemical stability keeping its high proton conductivity.