Neutron imaging of water transport in polymer-electrolyte membranes and membrane-electrode assemblies

Neutron imaging was been widely used to study the water distribution in proton exchange membrane fuel cell flow fields and gas diffusion layer. However, due to the limitation of spatial resolution, there has been little focus on the water transport process in the membrane and catalyst layer. Here we report on measurements made on thick membranes under saturation gradients which show no "jump condition" and on thick cathode catalyst layers to understand the water transport issues in a nonprecious metal catalyst. Finally, we speculate on the possibility of obtaining neutron images with ∼1 μm spatial resolution.