Design of a Reduction-Resistant Ce0.8Sm0.2 O 1.9 Electrolyte Through Growth of a Thin BaCe1−xSmxO3−α Layer over Electrolyte Surface

A method that can block off electronic current through a samaria-doped ceria (SDC, Ce 0 . 8 Sm 0 . 2 O 1 . 9 ) electrolyte is proposed. A thin BaCeO 3 -based layer 12 μm thick was grown by a solid-state reaction of the electrolyte substrate and a BaO film deposited previously over the substrate surface at 1500°C. A homogeneous junction between the layer and the electrolyte was formed, thus allowing no delamination and cracking of the layer. Tolerance of this layer to CO 2 was high enough to suppress decomposition into BaCO 3 and CeO 2 . Open-circuit voltages of a hydrogen-air fuel cell with the coated SDC electrolyte were near 1 V or more in the range of 600-950°C. The resulting peak power density was higher than that of a fuel cell with an uncoated SDC electrolyte.

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