Proton-Conducting Ceramics Based on Barium Hafnate and Cerate Doped with Zirconium, Yttrium, and Ytterbium Oxides for Fuel Cell Electrolytes

Nanopowders of the compositions BaHf1 – xYbxO3 – δ (x = 0.04, 0.08, 0.10) and BaCe0.9 – xZrxY0.1O3 – δ (x = 0, 0.5, 0.6, 0.7, 0.8) were synthesized by the combined crystallization of nitric acid salts and the citrate-nitrate method. Those nanopowders were used to produce ceramic materials with a cubic crystal structure of the perovskite type, with a grain size of ~20–70 nm. The study of electrophysical properties revealed that they have a proton type of conductivity in the temperature range of 500–700°C; σ = 10–2–10–5 S/cm. The type and mechanism of electrical conductivity of ceramics of the composition BaHf1 – xYbxO3 – δ (x = 0.04, 0.08, 0.10) were studied both experimentally and using theoretical calculations by computer modeling using the electron density functional method; the results are in good agreement. The research shows the prospects of using the obtained ceramic materials as proton-conducting electrolytes for solid oxide fuel cells.