Structural, electrical and transport properties of yttrium-doped proton-conducting strontium cerates

Series of SrCe1−xYxO3−δ solid solutions with x varying between 0 and 0.2 were prepared by solid-state reaction method. XRD results revealed that samples with 0 ≤ x < 0.1 (SrCe1−xYxO3−δ) are homogenous perovskite phases, while the samples with higher concentration of yttrium contain admixture of other phase (identified as Sr2CeO4). According to SEM observations the samples were dense with uniform grain sizes within 3–5 μm. Impedance spectroscopic investigations revealed a strong influence of Y concentration on electrical properties of SrCe1−xYxO3−δ. The activation energies of the total electrical conductivity as well as grain boundary and bulk components have been determined. Mixed ionic-electronic conductivity in studied materials at experimental conditions has been observed. Potentiometric measurements of EMF versus temperature of solid cells containing studied materials as solid electrolytes were performed in order to determine ionic transference numbers versus temperature.