Experimental Visualization of the Diffusional Pathway of Oxide Ions in a Layered Perovskite-type Cobaltite PrBaCo₂O_5+δ

Abstract

Layered perovskite-type cobaltite PrBaCo2O5+δ is an oxide-ion and electronic mixed conductor with high oxide-ion conductivity and is promising for potential use in SOFC (solid oxide fuel cell) cathodes and oxygen membranes. The crystal structure and oxide-ion diffusional pathway of PrBaCo2O5+δ at 596 and 1000 °C have been investigated by in situ high-temperature neutron powder diffraction and a maximum-entropy method (MEM)-based nuclear-density analysis. The oxide ions of PrBaCo2O5+δ two-dimensionally and anisotropically diffuse through equatorial and deficient apical oxygen sites along the ⟨101⟩ directions in the Pr–Co–O ion-conducting slab.