Diffusion-reaction-conduction processes in porous electrodes: the electrolyte wedge problem

This work studies mathematical issues associated with steady-state modellin g of diffusion-reaction-conduction processes in an electrolyte wedge (menis cus corner) of a current-producing porous electrode. The discussion is appl icable to various electrodes where the rate-determining reaction occurs at the electrolyte-solid interface; molten carbonate fuel cell cathodes are us ed as a specific example. New modelling in terms of component potentials (l inear combinations of electrochemical potentials) is shown to be consistent with tradition concentration modelling. The current density is proved to b e finite, and asymptotic expressions for both current density and total cur rent are derived for sufficiently small contact angles. Finally, numerical and asymptotic examples are presented to illustrate the strengths and weakn esses of these expressions.