Densification and Proton Conductivity of La1-xBaxScO3-delta Electrolyte Membranes

Bain La1-xBaxScO3-delta 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 Co3O4 sintering additive. An addition of only 0.5 wt% of Co3O4 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 La1-xBaxScO3-delta, which reduces the stability of protons: it reduces the enthalpy of the hydration reaction, but increases the mobility of protons. Thus, the Co3O4 sintering additive causes a complex of negative effects on the conductivity of La1-xBaxScO3-delta materials. Only high-temperature (1800 degrees C) processing with protection against Ba loss contributes to the production of dense La1-xBaxScO3-delta ceramics. The chemical composition of such ceramics corresponds well to the specified one, which ensures high water uptake and, consequently, high proton conductivity.

Automated summary

The dense ceramic production of perovskite La1-xBaxScO3-δ faces challenges due to impaired sintering and decreased material conductivity. High-temperature processing and the introduction of Co3O4 sintering additive are effective methods, but can negatively affect material stoichiometry and proton stability.