Influence of Ca-doping in layered perovskite PrBaCo2O5+δ on the phase transition and cathodic performance of a solid oxide fuel cell†
Layered perovskite oxides with the formula LnBaCo2O5+δ (Ln = Pr, Nd, Sm and Gd) have received attention as promising cathode materials for solid oxide fuel cells (SOFCs) because of their high oxygen diffusion and surface exchange coefficients. Recently, many researchers have reported that substituting barium with strontium or calcium can increase the structural stability, electrical conductivity, and catalytic activity of LnBaCo2O5+δ. In this study, we investigated the effect of Ca doping on the structural, electrical, and electrochemical properties of PrBa1−xCaxCo2O5+δ (x = 0, 0.1, 0.2, 0.3 and 0.4). Increasing the amount of Ca dopant changed the structure of PrBa1−xCaxCo2O5+δ from a layered perovskite to a simple perovskite. At x = 0.3, co-existence of the simple and the layered perovskite structure is observed. Electrical conductivity and electro-chemical performance were improved with increasing amount of Ca in the layered perovskite structure and declined with increasing amount of the simple perovskite phase.