Tetragonal Y-doped zirconia: Structure and ion conductivity

Zirconia is of great industrial importance as support for catalysts and as ion conductor. Especially when mechanical stability is needed in environments with varying temperature the tetragonal modification is superior, because of its high resistivity against physical shocks and thermal stresses. In this study density functional theory is used to investigate the interaction between Y impurities and oxygen vacancies and to develop in this way a structural model for Y-doped zirconia. For every two Y defects an O vacancy is formed at a distance of about 4.11 Angstrom to each dopant. An activation energy for ion conductivity of 0.87 eV is calculated in very good agreement with experimental findings.