Performance of Solid Oxide Fuel Cells with LSGM-LSM Composite Cathodes

Abstract

Anode-supported cells comprising zirconia (YSZ) anode, thin YSZ electrolyte, and composite cathodes containing a mixture of (LSM) and (LSGM) were fabricated. The relative proportions of LSGM and LSM were varied between 30 wt % % LSM and 70 wt % % LSM, while the firing temperature was varied between 1000 and 1200°C. The cathode interlayer composition had a profound effect on cathode performance at 800°C with overpotentials ranging between 60 and 425 mV at and exhibiting a minimum for 50 wt % % LSM. The cathodic overpotential decreased with increasing firing temperature of the composite interlayer in the range and then increased dramatically for the interlayer fired at 1200°C. The cell with the optimized cathode interlayer of 50 wt % % LSGM fired at 1150°C exhibited an area specific cell resistance of and a maximum power density of at 800°C. Chemical analysis revealed that LSGM reacts with YSZ above 1000°C to form the pyrochlore phase, The formation of the pyrochlore phase at the interface between the LSGM/LSM composite cathode and the YSZ electrolyte limits the firing time and temperature of the cathode interlayer. © 2002 The Electrochemical Society. All rights reserved.