%0 Journal Article
%A Adam Z Weber
%B Journal of Power Sources
%D 2010
%G eng
%P 5292-5304
%R 10.1016/j.jpowsour.2010.03.011
%T Improved modeling and understanding of diffusion-media wettability on polymer-electrolyte-fuel-cell performance
%V 195
%8 08/2010
%X <p><span>A macroscopic-modeling methodology to account for the chemical and structural properties of fuel-cell diffusion media is developed. A previous model is updated to include for the first time the use of experimentally measured capillary pressure–saturation relationships through the introduction of a Gaussian contact-angle distribution into the property equations. The updated model is used to simulate various limiting-case scenarios of water and gas transport in fuel-cell diffusion media. Analysis of these results demonstrate that interfacial conditions are more important than bulk transport in these layers, where the associated mass-transfer resistance is the result of higher capillary pressures at the boundaries and the&nbsp;</span>steepness<span><span>&nbsp;of the capillary pressure–saturation relationship. The model is also used to examine the impact of a&nbsp;microporous&nbsp;layer, showing that it dominates the response of the overall diffusion medium. In addition, its primary mass-transfer-related effect is suggested to be limiting the&nbsp;</span>water-injection&nbsp;sites into the more porous gas-diffusion layer.</span></p>