Novel lanthanum and cerium coatings on (Ba, Sr)-ferrate cathodes for intermediate-temperature solid oxide fuel cells

Ba0.5Sr0.5FeO3-δ (BSF) and Nb-doped BSF (BSNF) particles were coated with single or combined La and Ce (LC) components by a novel semi-organic solution method. Ce-coated BSF (BSF-x Ce) presented a cubic structure after heat treatment. Sintering BSF-x Ce and BSNF-x LC at 1150 °C for 6 h reduced the grain sizes. Among the coated samples, 3.75 mol% LC-coated BSNF (BSNF-3.75 LC) presented the most significant conductivity increase. AC impedance data indicate that the LC coating decreased the ohmic and diffusion resistances in half-cells with a BSNF-x LC cathode and (La0.75Sr0.2Ba0.05)0.175Ce0.825O1.891 (LSBC) electrolyte. The power density of the BSNF-3.75 LC/LSBC/Pt half-cell at 650 °C far exceeds that of BSF/LSBC/Pt at 700 °C. The Ce coating on BSF and LC coating on BSNF provided lattice stability and better BSF cathode-LSBC electrolyte adhesion. LC coating enhanced the cell performance by increasing the triple-phase boundaries (TPBs) in the solid oxide fuel cell (SOFC).