Effect of Cu doping on Ba0.5Sr0.5Fe1−xCuxO3−δ perovskites for solid oxide fuel cells: A first-principles study

• Ba0.5Sr0.5Fe1−xCuxO3−δ was simulated using first-principles.
• Thermodynamic stability decreases with the incorporation of Cu into the structure.
• Oxygen vacancy formation and diffusion barriers decrease with the Cu-substitution.
• Copper inclusion in the structure brings the O p-band closer to the Fermi level.
• p-band proximity to Fermi level promotes an increase of the ORR activity.

Nowadays a rational design of solid oxide fuel cells (SOFCs) cathodes is possible thanks to first-principles calculations based on density functional theory (DFT). We study the effect of Cu-doping in the bulk properties for the perovskite Ba0.5Sr0.5Fe1−xCuxO3−δ (with x = 0, 0.25 and 0.50) and correlate the results with previous experimental characterization. Bulk properties such as geometric structure, charge analysis, thermodynamic stability, vacancy formation energy, oxygen diffusion and electronic structure where studied in detail to provide an explanation of the oxygen reduction reaction (ORR) activity enhancement with Cu-doping. The results obtained here, using GGA+U, demonstrate the first-principles approach gives useful information that allows the prediction and explanation of experimental characterizations.