A Highly Efficient and Robust Perovskite Anode with Iron-Palladium Co-exsolutions for Intermediate-Temperature Solid-Oxide Fuel Cells.

The low performance and insufficient catalytic activity of perovskite anodes hinder their further application in intermediate-temperature solid-oxide fuel cells (IT-SOFCs). A novel La0.8 Sr0.2 Fe0.9 Nb0.1 Pd0.04 O3-δ (LSFNP) anode material has been developed with Fe-Pd co-exsolutions for IT-SOFCs. Fe0 and Pd0 metallic nanoparticles are confirmed to exsolve on the surface of the perovskite anode during operation under a hydrogen atmosphere. The introduced Pd exsolutions promote the charge-transfer process slightly and the H2 -adsorption ability of the La0.8 Sr0.2 Fe0.9 Nb0.1 O3-δ (LSFN) parent anode significantly, as metallic Pd is a conductor with excellent catalytic activity and an absorber of hydrogen that can absorb a large amount of H2 by forming unstable chemical bonds. A single cell with the LSFNP anode exhibits high output performance (maximum power density of 287.6 mW cm-2 at T=800 °C by using humidified H2 as the fuel), excellent redox stability, and considerable coking and sulfur tolerances. After the introduction of Pd exsolutions, the increase in the electrochemical performance is more significant under low H2 concentrations and at low temperatures with a maximum power density ratio of the LSFNP anode cell/LSFN anode cell reaching 18 under 5 % H2 /argon at T=650 °C. Pd-decorated LSFNP is a high-performance, redox-stable, coking-tolerant, and sulfur-tolerant anode material for IT-SOFCs, making Pd exsolution a reliable nanodecoration strategy to improve the low kinetics of perovskite anodes.