Lithium manganite development as a molten carbonate fuel cell cathode

Technical Report · Wed May 01 00:00:00 EDT 1991

OSTI ID:5739101

Smith, J L; Kucera, G H; Brown, A P ^[1]

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1. Argonne National Lab., IL (USA)

A number of Molten Carbonate Fuel Cell system studies indicate the potential for significant cost savings by operation at elevated pressure conditions (6--10 atm). Hampering operation at elevated pressure at this time is the problem of slow dissolution at the standard MCFC nickel oxide cathode. This program focused on the development of doped lithium manganite, a potential alternative material. Li{sub 2}MnO{sub 3} is thermodynamically stable in the cathode environment of the molten carbonate fuel cell. That is, it will exist indefinitely without transformation to another manganese compound in the full range of conditions from typical inlet to typical outlet. Manganese will not reduce to metal in the anode environment so the Li{sub 2}MnO{sub 3} cathode is inherently not subject to the migration problem of NiO. This has been confirmed through previous cell testing. The stable undoped compound is an n-type conductor and has a resistivity of about 700 ohm-cm in the cathode environment (temperature and cover gas). Successful application of the material for the MCFC cathode therefore is dependent on improvement of the conductivity through doping. The effect of Ca, Zn, Al, Nb, and W as dopants was examined. Testing included conductivity as a function of temperature and cover gas, Seebeck measurements as a function of temperature and cover gas, and TGA measurements as a function of cover gas. The results of the work indicate that with doping the bulk resistivity of Li{sub 2}MnO{sub 3} can be reduced to as low as 13 ohm-cm at 650{degrees}C and under typical cathode cover gas. 5 figs., 4 tabs.

• Research Organization: Electric Power Research Inst., Palo Alto, CA (USA); Argonne National Lab., IL (USA)
• Sponsoring Organization: EPRI; Electric Power Research Inst., Palo Alto, CA (USA)
• OSTI ID: 5739101
• Report Number(s): EPRI-GS-7288
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
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ALKALI METAL COMPOUNDS
ALKALINE EARTH METALS
ALUMINIUM
CALCIUM
CATHODES
CERAMICS
CHALCOGENIDES
CHEMICAL REACTIONS
CORROSION
DIRECT ENERGY CONVERTERS
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTROCHEMICAL CELLS
ELECTRODES
ELEMENTS
FUEL CELLS
HIGH-TEMPERATURE FUEL CELLS
LITHIUM COMPOUNDS
LITHIUM OXIDES
MANGANESE COMPOUNDS
MANGANESE OXIDES
MATERIALS
MATERIALS TESTING
METALS
MOLTEN CARBONATE FUEL CELLS
NIOBIUM
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
TESTING
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TUNGSTEN
ZINC