Sr0.25Bi0.5FeO3 (delta) (SBF) has been studied as a cathode material for lo
w- and intermediate-temperature (600-850 degreesC) solid oxide fuel cells (
SOFCs) based on the La0.9Sr0.9Ga0.9Mg0.1O3 (LSGM) electrolyte. The observed
cathodic current density passing through an SBF/LSGM interface at 840 degr
eesC in pure oxygen is about 1 A . cm(-2) at an overpotential of 40 mV, muc
h higher than that for an LaxSr1-xMnO3 electrode under similar conditions r
eported in the literature. Analysis indicates that the electrode kinetics i
s controlled primarily by mass transfer at high temperatures and by charge
transfer at low temperatures. The inductive loops of the impedance spectra
further suggest that the adsorption of intermediate species is involved in
the interfacial reaction.