Nanotech 2003 Vol. 3
Nanotech 2003 Vol. 3
Technical Proceedings of the 2003 Nanotechnology Conference and Trade Show, Volume 3

Fuel Cells Chapter 11

Modeling Water Uptake of Proton Exchange Membranes

Authors: P. Berg and K. Promislow

Affilation: Simon Fraser University, Canada

Pages: 493 - 496

Keywords: PEM fuel cell

Abstract:
Water content in Nafion membranes of proton exchange membranes (PEM) is crucial to its functionality. The adsorption of liquid water occurs on a time scale of seconds, while the desorption (drying) time scale is on the order of hours. In this contribution, we show that these disparate phenomena can be modeled by the same nonlinear diffusion model. Two essential ingredients to match experimental results are: 1) a diffusion coefficient that varies dramatically across the water content regime of interest, 2) a boundary condition that couples the water flux at the interface to the water content of the membrane and the sorption equilibrium prescribed by the environment. We demonstrate that the hydration-dehydration dichotomy arises from an intrinsic hysteresis implicit in the nonlinear model.

Modeling Water Uptake of Proton Exchange Membranes

ISBN: 0-9728422-2-5
Pages: 560