Modeling the impact of cation contamination in a polymer electrolyte membrane fuel cell
Advances in Electrocatalysis, Materials, Diagnostics and Durability
Advanced diagnostics, models and design
Low-temperature fuel cells
Published Online: 15 DEC 2010
Copyright © John Wiley & Sons, Ltd. All rights reserved.
Handbook of Fuel Cells
How to Cite
Greszler, T. A., Moylan, T. E. and Gasteiger, H. A. 2010. Modeling the impact of cation contamination in a polymer electrolyte membrane fuel cell. Handbook of Fuel Cells. .
- Published Online: 15 DEC 2010
Starting from fundamental principles, we have developed an isothermal, one-dimensional model for cation contamination of a proton exchange membrane (PEM) fuel cell. When current is drawn, the foreign cations migrate toward the cathode under the influence of the potential gradient while diffusion acts to balance this migration. The model provides the electrolyte potential along with the concentration of water, cation, and proton across the membrane electrode assembly (MEA) at steady-state condition. The voltage loss associated with cation contamination is largely thermodynamic in nature owing to the proton concentration (pH) difference that develops between the anode and cathode. This potential loss is proportional to current density and inversely proportional to water content. If the cation fraction in the cathode approaches unity, the cell current becomes limited because of proton starvation. The model is validated with experimental hydrogen pump performance data using lithium-doped MEAs. Hydrogen/oxygen operation is presented experimentally and discussed, but not explicitly modeled because of the added complications introduced by the sluggish oxygen reduction reaction kinetics. Experimental data for cobalt-doped MEAs, which can react in the cathode when the local pH increases above five, is presented and explained with the aid of cobalt's Pourbaix diagram. Finally, the effect of cobalt ion contamination (e.g., from PtCo cathode catalysts degradation) on H2/air PEMFC performance under automotive conditions is shown.
- hydrogen pumping;
- proton exchange membrane fuel cell;