Effective promotion of oxygen reduction activity by rare earth doping in simple perovskite cathodes for intermediate-temperature solid oxide fuel cells

The development of highly efficient cathode materials at intermediate temperatures is critical to realize the large-scale commercialization of solid oxide fuel cells (SOFCs). Here, a facile way is presented to tune both the crystal structure and the electrochemical performance of simple perovskite oxides as cathode materials by doping rare earth cations (La, Pr, Nd) in A site. The obtained cubic perovskites Ln(x)Ba(1-)xCo(0.7)Fe(0.3)O(3-delta) (Ln = La, Pr, Nd, x = 0.1, 0.2) exhibit enhanced electrocatalytic activity in comparison with their parent compound BaCo0.7Fe0.3O3-delta, with Pr(0.1)Ba(0.9)Co(0.7)Fe(0.3)O(3-delta )reaching area specific resistance of 0.038 and 0.026 Omega cm2 and peak power densities of 905.9 and 1236.4 mW cm(-2) at 650 and 700 degrees C, respectively. Such enhancement is a result of the stabilized cubic structure and the promoted oxygen vacancy formation and oxygen adsorption-dissociation process due to rare-earth doping (Pr is more effective for its redox-active character) by the combination of experimental characterization and first-principles calculation. Furthermore, Pr-doped materials also maintain favorable durability at 600 degrees C (800 mA cm(-2) for similar to 150 h). These findings in this work may provide new insights into the design of cathode materials for other perovskite systems in SOFCs, especially those involving rare earths.