On the sol-gel synthesis and characterization of (BaSr)(CeZr)O₃-based fuel cell electrolytes

Proton-conducting ceramics have been very useful due to their potential applications in fuel cells, electrolysers, and hydrogen membranes. The proton-conducting fuel cell electrolytes (Ba_1−xSr_x)(Ce_0.75Zr_0.10Y_0.15)O_3−δ (x = 0–1.0) have been synthesized through sol-gel method and characterized with regard to phase, structural stability, and electrical conductivity. The structural behavior has been investigated by X-ray diffraction and theRaman spectroscopy. The XRD analysis shows perovskite-type cubic structure and values of lattice parameter lie in the range of ~4.29 to ~4.40 Å. Strontium substitution leads to lattice contraction, strengthening of the metal-oxygen bond, and increase of oxygen content (3−δ). The Raman spectra show different types of stretching/vibrations corresponding to octahedral, M-O stretching, and oxygen vacancies. The electrical conduction was found to be protonic in nature and decreases with increase of strontium insertion. The composition x = 0.4 shows relatively better structural stability against humid air/boiling water condition while inferior in carbon dioxide atmosphere.