The effect of calcium doping on the improvement of performance and durability in a layered perovskite cathode for intermediate-temperature solid oxide fuel cells

Abstract

Layered perovskite oxides have received extensive attention as promising cathode materials for solid oxide fuel cells (SOFCs) because of their faster diffusion coefficient and oxygen transport kinetics. With the goals of enhancing electrochemical properties and improving the durability, this study focuses on the effect of calcium (Ca) doping in PrBa0.5Sr0.5−xCaxCo2O5+δ (x = 0 and 0.25) layered perovskite oxides through an investigation of their structural characteristics, electrical properties, redox behavior, electrochemical performances, and stability. In the temperature range of 100–750 °C, the electrical conductivity of PrBa0.5Sr0.25Ca0.25Co2O5+δ (PBSCaCO) is higher than that of Ca-free PrBa0.5Sr0.5Co2O5+δ (PBSCO). The area specific resistance (ASR) value of PBSCaCO–GDC (0.079 Ω cm2) is lower than that of PBSCO–GDC (0.093 Ω cm2) at 600 °C, based on a GDC electrolyte. Moreover, PBSCaCO–GDC achieves a good performance of 1.83 W cm−2 at 600 °C. PBSCaCO shows a stable power output without observable degradation for 100 h. On the basis of these results, the PBSCaCO cathode is an excellent candidate for IT-SOFC applications.