On modelling molten carbonate fuel-cell cathodes by electrochemical potentials

We derive an electrochemical-potential model for the peroxide mechanism des cribing the electrochemistry of a molten carbonate fuel cell cathode. The a dvantages of this model include elegantly combining the chemical and electr ical processes, making clear the connection to the underlying reaction stoi chiometry, and requiring the fewest equations consistent with that stoichio metry. The relationship between electrochemical-potential and concentration models is also discussed, along with a two-dimensional computational study of the effects of variations in electrode geometry or coefficient paramete rs. In particular, it is shown that the mean current density associated wit h a small portion of electrode may be increased by as much as a factor of f ive by carefully redistributing the electrolyte, and that on this scale the current density is most sensitive to the electrolyte diffusivity.