Abstract:
The disorder that occurs at the interface boundaries of heterogeneous phases in oxide composites is favorable for water adsorption, therefore, it is favorable for the appearance of proton conduction at these boundaries. High composite conductivity requires a well-developed network of interfacial boundaries, which is implemented in thin films synthesized at low temperatures. Such thin-film materials may prove to be promising proton electrolytes for solid oxide fuel cells designed to operate at low temperatures. The composites "pyrochlor LaZrO$_{3.5}$ + perovskite LaScO$_3$" served as a model object for studying this effect in the form of films up to 250 nm thick. The films were deposited on single crystal plates of ZrO$_2$ + 10 mol.%Y$_2$O$_3$ by spreading dosed amounts of alcohol solutions of nitrates and were studied in the entire range of compositions from 0 to 100% LaScO$_3$. Measurements of the transverse conductivity of films by the impedance method in the range 250–500$^\circ$C confirmed the appearance of a 1:1 composite conductivity maximum in humid air. There was no effect in dry air.
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