Sc-doped SrCoO3-δ cathode with enhanced oxygen reduction reaction catalytic activity and stability for low -temperature solid oxide fuel cell

Abstract

SrCoO_3-δ (SCO) as a perovskite material delivers enormous potential in electrolyte application for solid oxide fuel cell (SOFC) due to its high mixed conductivity and excellent catalytic activity toward oxygen reduction reaction (ORR) activity. However, SCO is suffering from the drawback of bad thermal stability at high temperatures, which limits its practical development. In our study, the doping strategy of Sc³⁺ is adapted to enhance the stability and promote the ORR catalytic activity of SCO cathode. The perovskite material SrSc_χCo_1-χO_3-δ (SS_χCO, χ=0, 0.1, 0.2, 0.3) is synthesized by solid phase method and used as the cathode to fabricate the fuel cell. The crystal structure, oxygen transport performance, electrical conductivity and stability of the SS_χCO serial cathode are characterized. The results show that the Sc³⁺ doping strategy can significantly improve the phase structure and electrochemical stability of SCO, and further facilitate ionic conduction. Among the SS_χCO serial cathode, the material with 0.2 Sc doping exhibits the lowest polarization impedance (0.35 Ω cm²) at 550 °C, highlighting its superior catalytic activity toward the ORR. Notably, the fuel cell fabricated from this optimized material achieves an impressive maximum power density of 748 mW cm⁻².