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This content will become publicly available on October 7, 2018

Title: Investigating Phase-Change-Induced Flow in Gas Diffusion Layers in Fuel Cells with X-ray Computed Tomography

The performance of polymer-electrolyte fuel cells is heavily dependent on proper management of liquid water. One particular reason is that liquid water can collect in the gas diffusion layers (GDLs) blocking the reactant flow to the catalyst layer. This results in increased mass-transport losses. At higher temperatures, evaporation of water becomes a dominant water-removal mechanism and specifically phase-change-induced (PCI) flow is present due to thermal gradients. This study used synchrotron based micro X-ray computed tomography (CT) to visualize and quantify the water distribution within gas diffusion layers subject to a thermal gradient. Plotting saturation as a function of through-plane distance quantitatively shows water redistribution, where water evaporates at hotter locations and condenses in colder locations. The morphology of the 2 GDLs on the micro-scale, as well as evaporating water clusters, are resolved, indicating that the GDL voids are slightly prolate, whereas water clusters are oblate. From the mean radii of water distributions and visual inspection, it is observed that larger water clusters evaporate faster than smaller ones.
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [1]
  1. Tufts Univ., Medford, MA (United States). Dept. of Mechanical Engineering
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS)
  3. Argonne National Lab. (ANL), Argonne, IL (United States). X-ray Science Division
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Storage and Distributed Resources Division
  5. Norwegian Univ. of Science and Technology, Trondheim (Norway). Dept. of Energy and Process Engineering
Publication Date:
Grant/Contract Number:
AC02-06CH11357; AC02-05CH11231
Accepted Manuscript
Journal Name:
Electrochimica Acta
Additional Journal Information:
Journal Volume: 256; Journal Issue: C; Journal ID: ISSN 0013-4686
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Fuel Cell Technologies Office (EE-3F)
Country of Publication:
United States
25 ENERGY STORAGE; 36 MATERIALS SCIENCE; porous media; fuel cells; phase-change-induced flow; evaporation; X-ray tomography
OSTI Identifier: