LaNi0.6Fe0.4O3–Ce0.8Sm0.2O1.9–Ag composite cathode for intermediate temperature solid oxide fuel cells

LaNi0.6Fe0.4O3 (LNF), LNF–Sm0.2Ce0.8O1.9 (SDC), and LNF–SDC–Ag cathodes on SDC electrolytes were investigated at intermediate temperatures using AC impedance spectroscopy. Results show that adding 50 wt.% SDC into LNF yields a significant low area specific resistance (ASR) which was found to be 0.92 Ω cm2 at 700 °C. Infiltrating 0.3 mg/cm2 Ag into LNF-50 wt.% SDC can improve the electronic conductivity and oxygen exchange reaction activity, and thereby remarkably decrease the ASRs. The ASR value of the LNF–SDC–Ag cathode is as low as 0.18 Ω cm2 at 700 °C, and 0.46 Ω cm2 at 650 °C. The long-term test shows that the LNF–SDC–Ag cathode may be a promising candidate for solid oxide fuel cells operating at temperatures lower than 650 °C.

► Adding 50 wt.% SDC into LNF yields a significant low area specific resistance (ASR).
► Infiltrating Ag into LNF-50 wt.% SDC can improve oxygen exchange reaction activity.
► The ASR value of the LNF–SDC–Ag cathode is as low as 0.46 Ω cm2 at 650 °C.