Proton concentration in 15 mol% Y-doped BaZrO3 proton conductors prepared at various temperatures

Proton concentration as a function of ambient temperature in 15 mol% Y-doped BaZrO3 proton conductors prepared at 1800 °C, 1600 °C and 1400 °C, is measured by thermo-gravimetric (TG) analysis. TG analysis reveals that the maximum proton concentration in the specimen prepared at 1400 °C is over 15 mol%. The value is over the limitation decided by hydration process via oxygen vacancy. Infrared diffuse reflection spectroscopy confirms that additional O–D stretching vibration exists in the specimen. Both results strongly suggest that not a few amounts of water incorporate in the specimen prepared at low temperature through other hydration process.