Nano La_0.6Ca_0.4Fe_0.8Ni_0.2O_3-δ decorated porous doped ceria as a novel cobalt-free electrode for "symmetrical" solid oxide fuel cells

Here we report that the nano La_0.6Ca_0.4Fe_0.8Ni_0.2O_3-δ (LCFN) decorated Sm_0.2Ce_0.8O_1.9 (SDC) composite oxide, prepared by the solution infiltration method, could function well as a cobalt-free electrode material for "symmetrical" solid oxide fuel cells (SOFCs). The structure, morphology, thermal expansion, oxygen reduction reaction activity and catalytic activity for methane oxidation of the as-prepared LCFN-infiltrated SDC electrode was investigated systematically. Under a reducing atmosphere, the partial segregation of metallic nickel from the LCFN perovskite lattice was demonstrated by SEM and STEM-EDX, and the XRD results suggested that the perovskite structure of LCFN still survived. Consequently, the good anode performance was expected due to the high catalytic activity of LCFN for methane oxidation and the excellent electrocatalytic activity of nano nickel for the methane reforming and electro-oxidation of hydrogen. In an air atmosphere, an area specific resistance as low as 0.12 Ω cm² was achieved at 600 °C. The SDC electrolyte supported "symmetrical" SOFC with the LCFN-infiltrated SDC electrode was then fabricated and tested, which delivered attractive peak power densities of 510 and 350 mW cm^-2 at 800 °C, operating on hydrogen and CH₄-O₂ fuels, respectively.