High performance Pd promoted Sm0.5Sr0.5CoO3–La0.8Sr0.2Ga0.8Mg0.15Co0.05O3−δ composite cathodes for intermediate temperature solid oxide fuel cells

Pd promoted Sm0.5Sr0.5CoO3 (SSC)–La0.8Sr0.2Ga0.8Mg0.15Co0.05O3−δ (LSGMC5) composite cathodes for intermediate temperature solid oxide fuel cells (ITSOFC) were prepared using the wet impregnation method. XRD analyses demonstrated that the Pd in the electrode was in the form of PdO. The activity for oxygen reduction of the electrode increased with the increase in the concentration of Pd in the electrode and with the decrease in the electrode sintering temperature. The electrode containing 2.4 wt% Pd sintered at 1123 K showed an electrode resistance about 0.12 Ω cm2 at near equilibrium conditions in oxygen at 873 K, which was only about one fourth of the electrode resistance without Pd addition. The addition of Pd species in the electrode showed no obvious effect on the mechanism of the oxygen reduction reaction.