Multicomponent Gd1−xSmxBa0.5Sr0.5CoCuO5+δ double perovskites as oxygen electrodes for solid oxide cells: Effect of chemical composition and electrospun morphology

• Gd0.75Sm0.25Ba0.5Sr0.5CoCuO5+δ double perovskite exhibits optimal structural, electrical, and thermomechanical properties among the tested compositions. • Electrodes fabricated via electrospinning outperform sol–gel-based electrodes, achieving a power density of 462 mW·cm−2 at 700°C in fuel cell mode. • Low polarization resistance of 0.086 Ω·cm² at 800°C demonstrates excellent electrocatalytic activity for oxygen reduction and evolution reactions. • The study validates the potential of multicomponent double perovskites as efficient oxygen electrodes for reversible solid oxide cells operating at intermediate temperatures.