Enhanced sintering and electrical properties of proton-conducting electrolytes through Cu doping in BaZr0.5Ce0.3Y0.2O3-δ.

To obtain BaZrO 3 -based electrolyte materials with both good sinterability and high proton conductivity, a Cu-doped B-site BaZr 0.5 Ce 0.3 Y 0.2- x Cu x O 3- δ (BZCYCu x ; x = 0, 0.05, 0.1) system is designed and synthesized. The effects of Cu doping on the crystal structure, sintering and electrical properties of BZCYCu x are systematically investigated. The BZCYCu 0.05 sample demonstrates the highest sintering density and total conductivity among the studied materials. BZCYCu 0.05 can be densified at 1250 °C, which is 300 °C lower than that for unmodified BZCY. The calculated results suggest that the increased conductivity in BZCYCu 0.05 benefits from a high apparent specific grain-boundary conductivity, which originates from a small space-charge potential and a large clean part of impurities in the electrolyte. A synthetic analysis based on impedance spectroscopy and distribution of relaxation time further confirms that BZCYCu 0.05 is more conductive. A single cell built using the BZCYCu 0.05 (∼46 μm) electrolyte shows an excellent power density of 258 mW cm−2 at 700 °C. These results indicate that BZCYCu 0.05 is a potential proton conductor for use in protonic ceramic fuel cells. [Display omitted] [ABSTRACT FROM AUTHOR]