Analytical Expression for Concentration Overpotential of Anode-Supported Solid Oxide Fuel Cell Based on the Dusty Gas Model

Abstract

The Dusty Gas model (DGM), despite being arguably the most accurate representation of gas diffusion in electrodes, is not readily adopted in the literature as it entails relatively expensive numerical integration of differential equations for concentration polarization calculations. To address this issue, this article demonstrates an analytical procedure to solve the DGM equations in a fuel cell electrode setting. In the process, it highlights the differences with previous attempts in the literature and improves upon the shortcomings. This paper specifically provides explicit expressions of concentration overpotentials of anode-supported solid oxide fuel cells (SOFCs) for binary and ternary gas systems via the analytical solution of DGM equations in one dimension without considering the viscous effects. The model predictions match very well with the experimental data available in the open literature. This paper also provides a semi-analytical framework for higher-order multicomponent systems. Finally, the effect of the pore-size distribution in the porous electrode on the concentration polarization is thoroughly explored.