Transport parameters for the modelling of water transport in ionomer membranes for PEM-fuel cells

• Published in: Electrochimica acta Vol. 49; no. 11; pp. 1731 - 1742
• Main Authors: Meier, Frank, Eigenberger, Gerhart
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 30.04.2004; Elsevier
• Subjects: Applied sciences; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; H 2-PEFC; Hydraulic permeability; Modelling; Water transport mechanism; Water transport number; Water transport number; H 2-PEFC; Water transport mechanism; Modelling; Hydraulic permeability; Polymeric membrane; H2-PEFC; Polymer solid electrolyte; Theoretical study; Water permeability; Transport process; Sulfonate polymer; Numerical simulation; Microstructure; Transport number; Proton exchange membrane fuel cells
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2003.12.004

The water transport number (drag coefficient) and the hydraulic permeability were measured for Nafion. The results show a significant increase of both parameters with increasing water content indicating that they are strongly influenced by the membrane microstructure. Based on these experimental studies a new model approach to describe water transport in the H 2-PEFC membrane is presented. This approach considers water transport by electro-osmosis caused by the proton flux through the membrane and by osmosis caused by a gradient in the chemical potential of water. It is parametrized by the measured data for the water transport number and the hydraulic permeability of Nafion. First simulation results applying this approach to a one-dimensional model of the H 2-PEFC show good agreement with experimental data. Therefore, the developed model can be used for a new insight into the dominating mechanisms of water transport in the membrane.