Unraveling the defect chemistry and proton uptake of yttrium-doped barium zirconate

A review of the experimental literature documenting water uptake in yttrium-doped barium zirconate in combination with new results obtained here show that much of the observed scatter can be explained in terms of barium deficiency, which furthermore induces a lowering in cell volume. In addition, through a comparison of weight changes under regular and heavy water vapor pressure, strong evidence is found for bulk oxidation of the oxide by water simultaneous with hydration.