Experimental and theoretical approaches for the investigation of proton conductive characteristics of La1-xBaxYbO3-δ

The proton conductive characteristics of La1-xBaxYbO3-δ (x = 0.02, 0.06, 0.10) were examined by an impedance analysis in the temperature range of 873-1473 K. The maximum proton concentrations in La1-xBaxYbO3-δ determined by the weight changes were almost 1/5 of the oxygen vacancies formed by the substitution of Ba. This result indicated that at least two types of oxygen vacancies, a hydratable oxygen vacancy and hydration independent one, exist in the crystal. The bond distances and electronic structure of the Ba-substituted LaYbO3 supercell with or without an oxygen vacancy were investigated by the first-principles molecular dynamics calculations. The substitution of Ba for the La-site of LaYbO3 was found to induce the local structure change of oxygen atoms surrounding the La atom.