Ion Conduction of BaPrO3-δ Thin Film with Mixed Valence State for SOFC Anode Electrode

The in-plane-oriented BaPrO3-δ thin film with mixed valence states has been prepared on an Al2O3 (0001) substrate by RF magnetron sputtering. The lattice constant decreases with increasing film thickness. The thin film has the mixed valence states of Pr4+ and Pr3+. The ~168 nm thickness film with small lattice constant exhibits high electrical conductivity and low activation energy of 0.58 eV. The thin film at wet air shows hole-ion mixed conduction and proton conduction, which is required as anode electrode of solid oxide fuel cell, at 300 °C.