A MODELING APPROACH TO THE CHARACTERIZATION OF THE LIMITING POLARIZATION BEHAVIOR OF GAS-DIFFUSION ELECTRODES

In this work, a new mathematical treatment for the description of the polarization behaviour of porous gas diffusion fuel cell electrodes is derived on the basis of a simple finite difference method and using the equations of the thin film-flooded agglomerate model. The method allows the fitting of the theoretical equations to the experimental oxygen reduction polarization results, considering the presence of ohmic drop inside the flooded agglomerate zones and the presence of a pressure gradient for the reactant in the gas channels. The method also allows the establishment of the state of the polarization losses along the thickness of the catalyst layer of the electrode under real operational conditions.