Rapid oxygen ion diffusion and surface exchange kinetics in PrBaCo2O5+x with a perovskite related structure and ordered A cations

Abstract

As part of an investigation of new cathode materials for intermediate temperature solid oxide fuel cells, we have investigated particular perovskite oxides with ordered A cations which, in turn, localize the oxygen vacancies into layers. The oxygen exchange kinetics of polycrystalline samples of the oxygen-deficient double perovskite PrBaCo2O5+x (PBCO) have been determined by electrical conductivity relaxation (ECR) and by oxygen-isotope exchange and depth profiling (IEDP). The ECR and IEDP measurements reveal that PBCO has high electronic conductivity and rapid oxygen ion diffusion and surface exchange kinetics. Both techniques demonstrate that the oxygen kinetics in this structure type are significantly faster than in corresponding disordered perovskites.