| Abstract: | La0.8Sr0.2FeO3-δ is a new kind of cathode material for intermediate SOFC, but its electrochemical activity is relative poor for the lanthanum gallate based solid oxide fuel cell. In this paper, a novel composite cathode of La0.8Sr0.2FeO3-δ/La0.9 Sr0.1Ga0.8Mg0.2O3-δ was prepared on the LSGM electrolyte substrate by screen-printing method. The results of cathodic polarization measurements show that the overpotential decreases significantly when the composite cathode is used instead of the La0.8Sr0.2FeO3-δ single layer cathode. The cathodic overpotential of the composite La0.8Sr0.2FeO3-δ/La0.9Sr0.1Ga0.8 Mg0.2O3-δ cathode is 150 mV at the current density of 0.2 A·m-2 at 800 ℃, while the cathodic overpotential of the La0.8 Sr0.2 FeO3-δ single layer cathode is higher thaN260 mV at the same condition. The electrochemical impedance spectroscopy was employed to investigate the polarization resistance of the cathode. The polarization resistance of the composite cathode is 1.20 Ω·m2 in open circuit condition, while the value of the single La0.8 Sr0.2 FeO3-δ cathode is 1.235 Ω·m2. |
