Densification and Proton Conductivity of La(1-x)Ba(x)ScO(3-δ) Electrolyte Membranes

Bain La(1-x)Ba(x)ScO(3-δ) impairs sintering and leads to a decrease in its ceramic density. Two approaches have been studied for obtaining dense ceramics: using a high processing temperature and the introduction of a Co(3)O(4) sintering additive. An addition of only 0.5 wt% of Co(3)O(4) sintering additive, despite the positive sintering effect, causes a noticeable violation of stoichiometry, with partial decomposition of the material. This can lead to the formation of cationic vacancies, which form associates with oxygen vacancies and significantly reduce the oxygen ion and proton conductivity of the materials. There is also a partial substitution of Co for Sc in La(1-x)Ba(x)ScO(3-δ), which reduces the stability of protons: it reduces the enthalpy of the hydration reaction, but increases the mobility of protons. Thus, the Co(3)O(4) sintering additive causes a complex of negative effects on the conductivity of La(1-x)Ba(x)ScO(3-δ) materials. Only high-temperature (1800 °C) processing with protection against Ba loss contributes to the production of dense La(1-x)Ba(x)ScO(3-δ) ceramics. The chemical composition of such ceramics corresponds well to the specified one, which ensures high water uptake and, consequently, high proton conductivity.