On modelling molten carbonate fuel-cell cathodes by electrochemical potentials

We derive an electrochemical-potential model for the peroxide mechanism describing the electrochemistry of a molten carbonate fuel cell cathode. The advantages of this model include elegantly combining the chemical and electrical processes, making clear the connection to the underlying reaction stoichiometry, and requiring the fewest equations consistent with that stoichiometry. 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 parameters. In particular, it is shown that the mean current density associated with a small portion of electrode may be increased by as much as a factor of five by carefully redistributing the electrolyte, and that on this scale the current density is most sensitive to the electrolyte diffusivity.