A-site Ca-doped layered double perovskite Pr1-xCaxBa0.94Co2O5+δ as high-performance and stable cathode for intermediate-temperature solid oxide fuel cells

Abstract

Developing highly active and stable air electrode is crucial to large-scale commercialization of intermediate-temperature solid oxide fuel cells (IT-SOFCs). Herein we report A-site Ca-doped layered double perovskites, Pr1-xCaxBa0.94Co2O5+δ (PCxB0.94C, x = 0.1–0.3), as a family of promising cathode materials for catalyzing the oxygen reduction oxygen (ORR). Benefiting from enhanced electrical conductivity and promoted surface oxygen exchange/chemical diffusion rates, Pr1-xCaxBa0.94Co2O5+δ demonstrates an efficient ORR activity in intermediate-temperature region. The electrochemical performance of the samples is characterized by symmetrical half-cells and button fuel cells. Among all these compositions, Pr0.8Ca0.3Ba0.94Co2O5+δ (PC0.3B0.94C) exhibits the lowest polarization resistance (Rp) of 0.027 Ω cm2 at 700 °C. The peak power density (PPD) of 1114 mW cm-2 is achieved in the PC0.3B0.94C cathode-based button fuel cell at 700 °C, along with outstanding stability over a period of 130 h. The findings endow the potential utilization of the PC0.3B0.94C cathode for IT-SOFCs under the realistic conditions.