The effect of potassium on the properties of PrBa1−xCo2O5+δ (x = 0.00–0.10) cathodes for intermediate-temperature solid oxide fuel cells

• Modify the properties of PrBa1−xCo2O5+δ by introducing K during synthesis.
• The present of K resulted in a greater cation deficiency in the double perovskites.
• K lead to markedly decreased of Co ion content on the double perovskites' surfaces.

An understanding of the relationships between the processing, compositions, and properties of perovskites is vitally important in the search for high performance cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs). In this work, the properties of PrBa1−xCo2O5+δ (x = 0.00–0.10) double perovskites were modified by introducing K during synthesis, and their performances as the cathode materials for IT-SOFCs were then characterized. The addition of K resulted in a greater cation deficiency in the double perovskites, improving bulk oxygen transport. However, K addition also markedly decreased the Co ion content on the perovskites' surfaces, which significantly deteriorated the perovskites’ electrochemical performances related to the surface exchange of oxygen.