Probing water distribution in compressed fuel-cell gas-diffusion layers using X-ray computed tomography

• X-ray CT is used to observe in-situ water distribution in gas diffusion layers.
• Land and channel effects are resolved under varying compression levels.
• Strong correlation between local porosity and water saturation at high compressions
• 3D water clusters are visualized and characterized at different compressions.

X-ray computed tomography was used to investigate geometrical land and channel effects on spatial liquid-water distribution in gas-diffusion layers (GDLs) of polymer-electrolyte fuel cells under different levels of compression. At low compression, a uniform liquid-water front was observed due to water redistribution and uniform porosity; however, at high compression, the water predominantly advanced at locations under the channel for higher liquid pressures. At low compression, no apparent correlation between the spatial liquid water and porosity distributions was observed, whereas at high compression, a strong correlation was shown, indicating a potential for smart GDL architecture design with modulated porosity.

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