Surface Modification of Self-Assembled Composite Cathode for Solid Oxide Fuel Cells with NiO Nanoparticles

Surface modification with simple metal oxides is a promising strategy to improve the catalytic activity of perovskite-derived cathode materials for solid oxide fuel cells. Herein, a Pr0.6Sr0.4FeO3−δ–Pr1.2Sr0.8NiO4+δ composite cathode is synthesized through a one-pot self-assembly process, and the surface of the cathode is decorated with NiO nanoparticles. The incorporation of Ni results in the oxidation of Fe3+ into Fe4+, which is beneficial for p-type conduction in the cathode. Furthermore, the formation of NiO nanoparticles facilitates the surface exchange process of oxygen. The polarization resistance of the composite cathode is 0.017 Ω cm2 at 750 °C, and a single cell with that cathode presents the highest maximum power density of 2.15 W cm–2 at 750 °C and a promising durability of 240 h. These results demonstrate that the self-assembled NiO modification provides a cobalt-free and cost-effective strategy for highly active cathode materials.