Oxygen electrode reaction in molten carbonate fuel cells
Molten carbonate fuel cell system is a leading candidate for the utility power generation because of its high efficiency for fuel to AC power conversion, capability for an internal reforming, and a very low environmental impact. However, the performance of the molten carbonate fuel cell is limited by the oxygen reduction reaction and the cell life time is limited by the stability of the cathode material. An elucidation of oxygen reduction reaction in molten alkali carbonate is essential because overpotential losses in the molten carbonate fuel cell are considerably greater at the oxygen cathode than at the fuel anode. Oxygen reduction on a fully-immersed gold electrode in a lithium carbonate melt was investigated by electrochemical impedance spectroscopy and cyclic voltammetry to determine electrode kinetic and mass transfer parameters. The dependences of electrode kinetic and mass transfer parameters on gas composition and temperature were examined to determine the reaction orders and the activation energies. The results showed that oxygen reduction in a pure lithium carbonate melt occurs via the peroxide mechanism. A mass transfer parameter, D{sub O}{sup 1/2}C{sub O}, estimated by the cyclic voltammetry concurred with that calculated by the EIS technique. The temperature dependence of the exchange current density and the product D{sub O}{sup 1/2}C{sub O} were examined and the apparent activation energies were determined to be about 122 and 175 kJ/ mol, respectively.
- Research Organization:
- Texas A and M Univ., College Station, TX (United States). Dept. of Chemical Engineering
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG22-87PC79931
- OSTI ID:
- 7295482
- Report Number(s):
- DOE/PC/79931-T13; ON: DE92040180
- Resource Relation:
- Other Information: Thesis (Ph.D.). Contains thesis by Bhasker B. Dave: Oxygen reduction in lithium carbonate melt: Determination of electrode kinetic and mass transfer parameters
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ELECTRODES
CHEMICAL REACTIONS
MOLTEN CARBONATE FUEL CELLS
ACTIVATION ENERGY
ENERGY EFFICIENCY
LITHIUM CARBONATES
MASS TRANSFER
OXYGEN
PROGRESS REPORT
REDUCTION
VOLTAMETRY
ALKALI METAL COMPOUNDS
CARBON COMPOUNDS
CARBONATES
DIRECT ENERGY CONVERTERS
DOCUMENT TYPES
EFFICIENCY
ELECTROCHEMICAL CELLS
ELEMENTS
ENERGY
FUEL CELLS
HIGH-TEMPERATURE FUEL CELLS
LITHIUM COMPOUNDS
NONMETALS
OXYGEN COMPOUNDS
300502* - Fuel Cells- Performance & Testing