Electrochemical characteristics of cathodes in solid oxide fuel cells based on ceria electrolytes

Journal Article · Thu May 01 04:00:00 EDT 1997 · Journal of the Electrochemical Society

DOI:https://doi.org/10.1149/1.1837653· OSTI ID:511946

Goedickemeier, M; Sasaki, K; Gauckler, L J ^[1]; Riess, I ^[2]

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1. ETH Zuerich (Switzerland)
2. Technion IIT, Haifa (Israel). Dept. of Physics

The ionic current-overpotential characteristics of cathodes on ceria-based electrolytes have been evaluated by galvanostatic current-interrupt measurements. The measurements were carried out on mixed conducting ceria electrolytes under fuel cell operating conditions. The effect on the oxygen reduction kinetics of the simultaneous transport of electrons and oxygen was investigated. As model substances for cathodes were La{sub 0.8}Sr{sub 0.2}MnO{sub 3}, La{sub 0.84}Sr{sub 0.16}CoO{sub 3}, Pt, Ag, and Au. Cathode reaction mechanisms as a function of the transport properties are discussed for the different cathode materials. Steady-state cathode overpotentials were interpreted using a Butler-Volmer-type equation to describe charge-transfer processes and to evaluate exchange current densities. At 700 C the exchange current density of the best cathode La{sub 0.84}Sr{sub 0.16}CoO{sub 3} was 180 mA/cm{sup 2} whereas the one for La{sub 0.8}Sr{sub 0.2}MnO{sub 3} was only 30 mA/cm{sup 2}. In both cases the authors identified charge-transfer on the cathode material as the rate-limiting step.

• Sponsoring Organization: USDOE
• OSTI ID: 511946
• Journal Information: Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 5 Vol. 144; ISSN 0013-4651; ISSN JESOAN
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
36 MATERIALS SCIENCE
CATHODES
CERIUM OXIDES
COBALT OXIDES
ELECTRICAL PROPERTIES
ELECTROCHEMISTRY
GOLD
LANTHANUM OXIDES
MANGANESE OXIDES
PLATINUM
SILVER
SOLID ELECTROLYTE FUEL CELLS
STRONTIUM OXIDES