Ln0.6Sr0.4Co1−yFeyO3−δ (Ln = La and Nd; y = 0 and 0.5) cathodes with thin yttria-stabilized zirconia electrolytes for intermediate temperature solid oxide fuel cells

The electrochemical performances of the solid oxide fuel cells (SOFC) fabricated with Ln0.6Sr0.4Co1−yFeyO3−δ (Ln = La, Nd; y = 0, 0.5) perovskite cathodes, thin yttria-stabilized zirconia (YSZ) electrolytes, and YSZ–Ni anodes by tape casting, co-firing, and screen printing are evaluated at 600–800 °C. Peak power densities of ∼550 mW cm−2 are achieved at 800 °C with a La0.6Sr0.4CoO3−δ (LSC) cathode that is known to have high electrical conductivity. Substitution of La by Nd (Nd0.6Sr0.4CoO3−δ) to reduce the thermal expansion coefficient (TEC) results in only a slight decrease in power density despite a lower electrical conductivity. Conversely, substitution of Fe for Co (La0.6Sr0.4Co0.5Fe0.5O3−δ or Nd0.6Sr0.4Co0.5Fe0.5O3−δ) to reduce the TEC further reduces the cell performance greatly due to a significant decrease in electrical conductivity. However, infiltration of the Fe-substituted cathodes with Ag to increase the electrical conductivity increases the cell performance while preserving the low TEC.