Ba0.6Sr0.4Ce0.8-xZr xY0.2O3-δ (x = 0-0.8) proton-conducting oxides are prepared using a sol-gel complexing process. The effects of the Ce/Zr ratio on various material properties are systematically investigated. The sintered samples show a perovskite crystal structure without impurity phases and have a rather compact interior, making them suitable for use as a fuel cell electrolyte. Increasing the Zr content in the oxides causes lattice constriction and suppresses grain growth during sintering at 1600 C. The ionic conductivity of the oxides increases with increasing Ce/Zr ratio. At 800 C, Ba0.6Sr0.4Ce0.8Y0.2O 3-δ has a conductivity of as high as 0.14 S/cm. However, X-ray diffraction and Raman spectroscopy evaluations show that this oxide cannot withstand a CO2 atmosphere. A suitable substitution of Ce with Zr in the structure significantly improves the chemical stability of the oxide without significantly degrading conductivity.
- A. Energy storage materials
- B. Sol-gel synthesis
- C. Scanning and transmission electron microscopy
- C. X-ray diffraction
- D. Ionic conduction