Microstructure-property relations of solid oxide fuel cell cathodes and current collectors: Cathodic polarization and ohmic resistance

Journal Article · Thu Feb 01 00:00:00 EST 1996 · Journal of the Electrochemical Society

DOI:https://doi.org/10.1149/1.1836476· OSTI ID:212159

Sasaki, K; Wurth, J P; Gschwend, R; Goedickemeier, M; Gauckler, L J ^[1]

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1. Swiss Federal Inst. of Tech., Zuerich (Switzerland)

Microstructure, cathodic polarization, and ohmic resistance on the cathode side of ZrO{sub 2}-based solid oxide fuel cells have been studied for the intermediate temperature operation range between 700 and 900 C. Starting powder characteristics, powder calcination temperature, and sintering temperature strongly influence the final microstructure of cathodes. Electrochemical performance depends on these processing parameters as well as on the cathode thickness and the contact spacing of current collectors. A decrease in effective electrode area occurs both on the microscopic level with coarse and inhomogeneous cathode microstructure and on the macroscopic level with a wide contact spacing of the current collectors. The smaller effective electrode area causes inhomogeneous current density distribution and results consequently in higher ohmic losses originating from the electrolyte and higher cathodic polarization. These losses are evaluated using La{sub 0.85}Sr{sub 0.15}MnO{sub 3} cathodes with different microstructures and on the ZrO{sub 2}-8 mole percent Y{sub 2}O{sub 3} electrolyte. The influence of current path constrictions on the ohmic and nonohmic losses is demonstrated using Pt current collectors of different geometric spacings.

• Sponsoring Organization: USDOE
• OSTI ID: 212159
• Journal Information: Journal of the Electrochemical Society, Vol. 143, Issue 2; Other Information: PBD: Feb 1996
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
36 MATERIALS SCIENCE
SOLID ELECTROLYTE FUEL CELLS
CATHODES
CHARGE COLLECTION
LANTHANUM OXIDES
MICROSTRUCTURE
ELECTRICAL PROPERTIES
STRONTIUM OXIDES
MANGANESE OXIDES
PLATINUM
ZIRCONIUM OXIDES
YTTRIUM OXIDES
LOSSES
ELECTRIC POTENTIAL
FABRICATION
POWDER METALLURGY
CALCINATION
SINTERING