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Understanding the transport properties of porous materials plays an important role in the development and optimization of polymer electrolyte fuel cells (PEFCs). In this study numerical simulations of different transport properties are compared and validated with data obtained using recently developed experimental techniques. The study is based on a Toray TGP-H-060 carbon paper, a common gas diffusion layer (GDL) material in PEFC. Diffusivity, permeability, and electric conductivity of the anisotropic, porous material are measured experimentally under various levels of compression. A sample of the GDL is imaged with synchrotron-based X-ray tomography under three different compression levels. Based on these three-dimensional images, diffusivity, permeability, and conductivity are calculated numerically. Experimental and numerical results agree in general. Deviations are observed for the through-plane conductivity. An explanation for the discrepancy is presented and affirmed by numerical simulations on a virtually created structure model. This proves that numerical simulation based on tomography data is a versatile tool for the investigation and development of porous structures used in PEFCs.

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The local saturation in porous transport layers (PTL) has been determined using synchrotron-based x-ray micro-tomography. The water distribution inside the porous structure could be resolved on the scale of the pores. After phase segmentation of the image data, the measurement of the liquid saturation as function of the through plane coordinate of the PTL and the capillary pressure was possible. For verification, first experiments with complete cells are also shown.