Numerical modeling of an anode-supported SOFC button cell considering anodic surface diffusion

A two-dimensional isothermal mechanistic model of an anode-supported solid oxide fuel cell was developed based on button-cell geometry. The model coupled the intricate interdependency among the ionic conduction, electronic conduction, gas transport, and the electrochemical reaction processes. All forms of polarizations were included. The molecular diffusion, Knudsen diffusion, as well as the simplified competitive adsorption and surface diffusion were also considered. An electric analogue circuit was used to determine the effective hydrogen diffusivity. The model results showed good agreement with the published experimental data in different H2–H2O mixtures without any other calibrations after the parameter estimation according to the experimental data in baseline operating condition. The distributions of species concentration and current density were predicted and the effects of cathode area, gas components, and anode thickness on the cell performance were studied.