Development of LSM/YSZ composite cathode for anode-supported solid oxide fuel cells

This paper presents the effect of (La, Sr)MnO3 (LSM) stoichiometry on the polarization behaviour of LSM/Y2O3ZrO2 (YSZ) composite cathodes. The composite cathode made of A-site deficient (La0.85Sr0.15)(0.9)MnO3 (LSM-B) showed much lower electrode interfacial resistance and overpotential losses than that made of stoichiometric (La0.85Sr0.15)(1.0)MnO3 (LSM-A). The much poorer performance of the latter is believed to be due to the formation of resistive substances such as La2Zr2O7/SrZrO3 between LSM and YSZ phases in the composite electrode. A slight A-site deficiency (similar to0.1) was effective in inhibiting the formation of these resistive substances. A power density of similar to1 W cm(-2) at 800degreesC was achieved with an anode-supported cell using an LSM-B/YSZ composite cathode. In addition, the effects of cathodic current treatment and electrolyte surface grinding on the performance of composite cathodes were also studied.