Gas Transport in Porous Electrodes of Solid Oxide Fuel Cells

Abstract

Concentration polarization is a key SOFC performance parameter. It is caused by the limitation of transport of fuel or oxidant from the gas feeding channels through the electrodes to the reaction sites along the electrode/electrolyte interface. This paper presents the numerical simulations of gas transport in the porous electrodes of solid oxide fuel cells with an interdigitated flow channel design. By creating a convective component of mass transport in the porous electrodes, the interdigitated flow channel design could enhance the mass transport. The mass transport simulation was conducted using the FEMLAB software. Two porous media mass transport models, i.e. Fick's Model and the Dusty Gas Model (DGM) were used in the simulation. The simple but less accurate Fick's model is validated against the Dusty Gas Model results. It is found that for a combined diffusive and convective flow in the SOFC porous electrodes, when the fuel concentration is low and the pore size is small, the Dusty Gas Model should be used.