BaZr_0.2Ce_0.8-xY_xO_3-δ solid oxide fuel cell electrolyte synthesized by sol-gel combined with composition-exchange method

This study reports the synthesis of proton-conducting BaZr _0.2Ce_0.8-xY_xO_3-δ (x = 0-0.4) oxides by using a combination of citrate-EDTA complexing sol-gel process and composition-exchange method. Compared to those oxides prepared from conventional sol-gel powders, the sintered BaZr_0.2Ce_0.8-xY _xO_3-δ pellets synthesized by sol-gel combined with composition-exchange method are found to exhibit improved sinterability, a higher relative density, higher conduction, and excellent thermodynamic stability against CO₂. Moreover, the Pt/electrolyte/Pt single cell using such a BaZr_0.2Ce_0.6Y_0.2O _3-δ electrolyte shows an obviously higher maximum powder density in the hydrogen-air fuel cell experiments. Based on the experimental results, we discuss the improvement mechanism in terms of calcined particle characteristics. This work demonstrates that the BaZr_0.2Ce _0.8-xY_xO_3-δ oxides synthesized by sol-gel combined with composition-exchange method would be a promising electrolyte for the use in H⁺-SOFC applications. More importantly, this new fabrication approach could be applied to other similar ABO₃- perovskite material systems.