This study reports the synthesis of proton-conducting Ba 1-xKxCe0.6Zr0.2Y0.2O 3-δ (x=0.025-0.075) ceramics by using a combination of citrate-EDTA complexing sol-gel process and the composition-exchange method. Compared to the sintered oxides of similar composition prepared from conventional sol-gel powders, Ba1-xKxCe 0.6Zr0.2Y0.2O3-δ oxides synthesized by sol-gel combined with the composition-exchange method are found to exhibit improved sinterability, higher conductivity, more homogeneous phase, and excellent chemical stability against CO2. Among all sintered oxides in this study, the Ba0.925K0.075Ce 0.6Zr0.2Y0.2O3-δ pellet fabricated by this new method has the highest conductivity, 0.0094 S/cm at 800 C, which is higher than those pressed from conventional sol-gel powders in the K doping range of 0-15%. Based on the experimental results, we discuss the mechanism for improvement in these properties in terms of calcined particle characteristics. This work demonstrates that Ba1-xK xCe0.6Zr0.2Y0.2O 3-δ oxides synthesized by sol-gel combined with the composition-exchange method would be a promising electrolyte for H +-SOFC applications. More importantly, this new fabrication approach may be applied to other similar material systems, such as Sr-doped Ba(Ce,Zr)O3 ceramics.
- C. Ionic conductivity
- Chemical stability
- Proton-conducting electrolyte
- Solid oxide fuel cells