Electrochemical and Solid-State Letters · 2002 · 64 citations · 11 references
Natural SciencesMaterials EngineeringMaterials ScienceElectrochemical EngineeringElectrochemistryMaterials ChemistryCathode MaterialsElectrochemical CellsElectrode MaterialsElectrode-electrolyte InterfacesFuel CellsSolid-state ElectrolytesElectrochemical ConductivityElectrochemical Impedance AnalysisElectrochemical MeasurementsOxide ElectrolytesOxide Solid ElectrolytesScanning Electron MicroscopySolid Oxide Fuel Cell MaterialsSolid Oxide Fuel Cells
Functionally graded cathodes were fabricated by slurry coating process for honeycomb solid oxide fuel cells with yttria-stabilized zirconia (YSZ) electrolytes. The cathodes are composed of strontium-doped lanthanum manganate (LSM), gadolinia-doped ceria, and (LSCF). The LSM content was gradually decreased, while the LSCF content was gradually increased with the increasing distance away from the electolyte-electrode interface. Scanning electron microscopy investigation and electrochemical impedance spectroscopy measurements revealed that the electrochemical performance of the graded cathodes depends sensitively on the microstructures that were primarily determined by firing temperatures. The cathodes graded in composition show interfacial resistances about 10 times lower than traditional LSM-YSZ cathodes that have similar microstructures and thickness. The graded cathode fired at low temperature has an interfacial resistance as low as at 750°C, which is very encouraging for developing honeycomb fuel cells operated below 800°C. © 2002 The Electrochemical Society. All rights reserved.
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