Chemical stability and electrical and mechanical properties of BaZr_xCe_0.8-xY_0.2O₃ with CeO₂ protection method

This study investigated the decline in the conductivity and mechanical strength after CO₂ poisoning and found a new protective method for BaZr_xCe_0.8-xY_0.2O₃ proton-conducting electrolyte. The high temperature solid state reaction (SSR) was used in synthesizing electrolyte to naturally generate CeO₂ on the surface. A comparison of the oxides in the conductivity decline test revealed that the sample with CeO₂ on the surface substantially improved the stability of conductivity, reducing the decline ratio from 56% to 7% for BCY electrolyte and 50% to 7% for BCZY sample. Raman mapping results indicate the naturally generated CeO₂ on electrolyte surface can considerably reduce impurity formation and maintain the microstructure of electrolyte. This work demonstrates that samples with CeO₂ on the surface effectively protect the BaCeO₃-based proton-conducting electrolyte from CO₂ poisoning. This method may be applied to similar BaCeO₃-based perovskite materials as a new protective method.