Enhanced transport properties of Sn‐substituted proton‐conducting BaZr0.8Sc0.2O3–δ ceramic materials

High‐temperature proton conductors based on acceptor‐doped barium zirconate exhibit excellent chemical stability in atmospheres containing CO2 or H2O. However, due to their refractory nature, these conductors have a low grain growth rate, which negatively affects the overall electrical conductivity. A possible strategy for increasing the ionic conductivity of zirconates lies in the partial substitution of Zr‐ions with other isovalent dopants. In this work, we carried out systematic studies of the crystal structure, microstructure, hydration capacity, transport, and thermal properties of BaZr0.8–xSnxSc0.2O3–δ (x = 0, 0.1, and 0.2). According to X‐ray powder diffraction and scanning electron microscopy data, all studied ceramic samples have a cubic perovskite structure, whose average grain size decreases with tin doping. It is found that the composition with x = 0.1 exhibits the highest values in terms of total, ionic, grain, and grain‐boundary conductivities. The complex analysis of the obtained data shows that a low‐level substitution of Zr4+‐ with Sn4+‐ions is a competent approach for designing new proton‐conducting electrolytes attractive for high‐temperature applications.