Isolation of transport mechanisms in PEFCs using high resolution neutron imaging

• High resolution neutron radiography used to determine through-plane water content.
• Test conditions chosen to push limitations of multi-phase models.
• Online database provides rich validation data for multiphase models.
• Flow field geometry significantly influences diffusion media saturation levels.
• Anode was more sensitive to water content with asymmetric flow field.

Liquid water saturation profiles were determined using high resolution neutron radiography for commercially available fuel cell materials and hardware. Temperature, pressure, and relative humidity (concentration) gradients were imposed on the cell to determine individual influences on water content for each gradient. The asymmetric anode/cathode channel/land architecture used in this work results in significant water accumulation in the anode diffusion media with saturation values of up to ∼50%. Anode water content was found to change substantially with imposed pressure or concentration gradient, whereas the cathode saturation profile remained relatively consistent, indicating the channel/land ratio and thickness have a determinant role in diffusion media retention. The data generated in this work has been made publicly available through www.pemfcdata.org, and should be useful for computational modelers seeking validation data.