Barium carbonate nanoparticle to enhance oxygen reduction activity of strontium doped lanthanum ferrite for solid oxide fuel cell

BaCO 3 nanoparticles are demonstrated as outstanding catalysts for high-temperature oxygen reduction reaction (ORR) on the La 0.8 Sr 0.2 FeO 3-δ (LSF) cathode for solid oxide fuel cells (SOFCs) based on ytrria-stabilized zirconia (YSZ) electrolytes. Thermal gravitational and X-ray diffraction measurements show that BaCO 3 is stable and chemically compatible with LSF under the fabrication and operation conditions of intermediate-temperature SOFCs. The BaCO 3 nanoparticles can greatly reduce the interfacial polarization resistance; from 2.96 to 0.84 Ω cm 2 at 700 °C when 12.9 wt % BaCO 3 is infiltrated to the porous LSF electrode on the YSZ electrolyte. Electrochemical impedance spectroscopy shows that there is about one order of magnitude decrease in the low-frequency resistance, indicating that BaCO 3 nanoparticles can greatly enhance the surface steps for ORR. Electrical conductivity relaxation investigation indicates about one order of magnitude increase in the chemical oxygen surface exchange coefficient when BaCO 3 is applied, directly demonstrating significant increase in the kinetics for ORR. In addition, LSF cathodes with infiltrated BaCO 3 nanoparticles have shown excellent stability and substantially enhanced cell performance as demonstrated with single cells, suggesting BaCO 3 nanoparticles are very effective in enhancing ORR on LSF. • BaCO 3 nanoparticles enhance the oxygen reduction activity of LSF cathode. • BaCO 3 increases oxygen chemical exchange coefficient by a factor of ∼10. • BaCO 3 nanoparticles are very stable upon heating at 700 °C for more than 300 h.