Doped cerium oxide for molten carbonate fuel cell cathodes
- Case Western Reserve Univ., Cleveland, OH (USA)
Donor-doped Ce0{sub 2} was studied as a cathode material for the molten carbonate fuel cell. The electrical conductivity of Nb-doped Ce0{sub 2} was measured as a function of dopant level (0.80-1.3 cat%), temperature (600--900{degree}C), and partial pressure of oxygen (10{sup {minus}12} {minus}1 atm). The conductivity of Ta- and W-doped cerium oxide was also measured in air from 600 to 900{degree}C. The corrosion resistance of pure and Nb-doped Ce0{sub 2} in molten carbonate was studied as a function of atmosphere and material preparation procedure, and characterized using electron microscopy and solubility measurements. Nb-doped Ce0{sub 2} showed excellent corrosion resistance to molten carbonate, when silicate grain boundary phases were eliminated. The electrical conductivity is near the target value of 0.1 {Omega}{sup {minus}1}cm{sup {minus}1} at 650{degree}C and <10{sup {minus}1} atm oxygen pressure. For pO{sub 2}{ge} 0.2 atm, CeNb0{sub 4} precipitation sharply reduces the electrical conductivity. Preliminary in-cell testing of tape cast Ce0{sub 2}/Nb electrodes showed no evidence of corrosion. Electrical losses, however, were higher than for lithiated nickel oxide (Ni0/Li). Replacing Nb with W or Ta resulted in substantially higher electrical losses and greater corrosion resistance than Ni0/Li. 42 refs., 19 figs., 1 tab.
- Research Organization:
- Electric Power Research Inst., Palo Alto, CA (USA); Case Western Reserve Univ., Cleveland, OH (USA)
- Sponsoring Organization:
- EPRI
- OSTI ID:
- 6558418
- Report Number(s):
- EPRI-ER-6983
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
300503* -- Fuel Cells-- Materials
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& Auxiliaries
300505 -- Fuel Cells-- Electrochemistry
Mass Transfer & Thermodynamics
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400400 -- Electrochemistry
CERAMICS
CERIUM COMPOUNDS
CERIUM OXIDES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CORROSION
CRYSTAL STRUCTURE
DIRECT ENERGY CONVERTERS
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTROCHEMICAL CELLS
ELECTRODES
ELEMENTS
FUEL CELLS
HIGH-TEMPERATURE FUEL CELLS
KINETICS
MATERIALS
METALS
MICROSTRUCTURE
MOLTEN CARBONATE FUEL CELLS
NICKEL COMPOUNDS
NICKEL OXIDES
NIOBIUM
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
REACTION KINETICS
TANTALUM
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TUNGSTEN