Publication date: 10th April 2024
BaFeO3-d is a prototypical triple-conducting oxide with mobile protons, oxygen vacancies, and electron holes. Such materials are key components for protonic ceramic fuel/electrolysis cells and hydrogen permeation membranes.
BaFeO3-d can be doped with various redox-inactive cations in the perovskite's B-site, which typically increases the proton uptake.[1,2] This effect is attributed to the introduction of local lattice distortions (Fe-O-Fe buckling) that decrease the covalency of the Fe-O bonds.[3,4]
In the present poster, the variation of proton uptake with size and concentration of dopants such as Acc = Sc3+, Y3+, In3+, Zr4+, Ce4+, Sn4+ - covering a large range of ion radius and acid/base properties - is investigated using thermogravimetry. Dopants with size mismatch below 0.1 Å can be introduced in large concentration and form extended solid solutions, while the solubility of dopants with larger mismatch does not exceed 20%. The optimum dopant size and concentration for maximizing proton uptake while preserving a high electronic conductivity is discussed.