Am. Svensson et K. Nisancioglu, CURRENT DISTRIBUTION AT POROUS ELECTRODE-SOLID OXIDE ELECTROLYTE INTERFACE, Journal of the Electrochemical Society, 145(9), 1998, pp. 3130-3134
Citations number
14
Categorie Soggetti
Electrochemistry,"Materials Science, Coatings & Films
A two-dimensional model is developed fur transport of oxygen in a poro
us solid oxide fuel cell (SOFC) cathode with negligible oxygen ion con
ductivity in the bulk. Adsorption and surface diffusion of oxygen adso
rbates on the pore walls, interfacial diffusion of adsorbates, and ele
ctrochemical reaction kinetics at the electrode/electrolyte interface
are considered, as well as the nonuniform current and potential distri
bution in the electrolyte. In particular; the effect of a nonuniform c
urrent distribution along the electrode/electrolyte interface is inves
tigated. The results are compared to a previously developed one-dimens
ional model for SOFC perovskite cathodes based on the porous electrode
theory. The two models agree well, except in the case of strong inter
facial mass-transfer limitations. The benefit of an expanded reaction
zone along the electrode/electrolyte interface is demonstrated. Howeve
r, nonuniform current distribution at high current levels caused by di
ffusion limitations at the interface reduces the effective size of the
reaction zone and restricts this zone close to the three-phase bounda
ry.