A comparative study of NiO(Li), LiFeO[sub 2], and LiCoO[sub 2] porous cathodes for molten carbonate fuel cells

Journal Article · Wed Nov 30 23:00:00 EST 1994 · Journal of the Electrochemical Society; (United States)

DOI:https://doi.org/10.1149/1.2059349· OSTI ID:6594508

Makkus, R C ^[1]; Hemmes, K; Wit, J H.W. de ^[2]

---

1. Netherlands Energy Research Foundation ECN, Petten (Netherlands)
2. Delft Univ. of Technology (Netherlands). Lab. for Materials Science

Porous cathodes of NiO(Li), Co-doped LiFeO[sub 2], and LiCoO[sub 2] for the molten carbonate fuel cell (MCFC) were examined in a comparative study using electrochemical impedance spectroscopy at temperature of 923, 973, and 1023 K. Using this technique the contributions of charge transfer and diffusion to the impedance could be separated. The impedance results as a function of gas composition were compared with theoretical predictions using the thin-film model leading to the conclusion that the most predominant diffusing species in porous MCFC electrodes are molecular oxygen and carbon dioxide. The reaction mechanism is probably the same for all three cathodes involving either the reduction of peroxy-carbonate or the reduction of dissociated oxygen. The remaining difference in gas dependencies can then be explained by assuming a low coverage of oxide ions on LiFeO[sub 2] while NiO(Li) and LiCoO[sub 2] have intermediate coverage by oxide ions. From the temperature dependence of the impedance an estimate may be given of the activation energies of the polarization processes.

• OSTI ID: 6594508
• Journal Information: Journal of the Electrochemical Society; (United States), Journal Name: Journal of the Electrochemical Society; (United States) Vol. 141:12; ISSN JESOAN; ISSN 0013-4651
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
300502 -- Fuel Cells-- Performance & Testing
300503* -- Fuel Cells-- Materials
Components
& Auxiliaries
ACTIVATION ENERGY
ALKALI METAL COMPOUNDS
CATHODES
CHALCOGENIDES
CHEMICAL REACTIONS
COBALT COMPOUNDS
COBALT OXIDES
COMPARATIVE EVALUATIONS
DIRECT ENERGY CONVERTERS
ELECTRIC IMPEDANCE
ELECTROCHEMICAL CELLS
ELECTRODES
ENERGY
EVALUATION
FUEL CELLS
HIGH-TEMPERATURE FUEL CELLS
IMPEDANCE
IRON COMPOUNDS
IRON OXIDES
LITHIUM COMPOUNDS
LITHIUM OXIDES
MOLTEN CARBONATE FUEL CELLS
NICKEL COMPOUNDS
NICKEL OXIDES
OXIDES
OXYGEN COMPOUNDS
PERFORMANCE
PERMEABILITY
POROSITY
REDOX REACTIONS
TRANSITION ELEMENT COMPOUNDS