Simultaneous Neutron and Optical Imaging in PEM Fuel Cells

Water content and transport greatly impact the operation of a polymer electrolyte membrane (PEM) fuel cell and must be managed to maximize performance and durability. Water dynamics in operational PEM fuel cells were investigated by simultaneous neutron and optical imaging. By combining the two techniques, images of the liquid water dynamics in the flow field were recorded optically through the transparent window while simultaneously measuring the through-thickness water content at each planar location of the cell with the neutron imaging technique, thus providing two independent sets of data in an operational PEM fuel cell. Under certain conditions, the concurrent images provide complementary information that enables one to separate the water content in the channels from the water content within the membrane-electrode assembly comprised of the catalyst-coated membrane sandwiched between two gas diffusion layers, as well as distinguish between the water dynamics on the cathode and the anode side. This experimental approach offers a possibility for improved interpretation of water metrology data obtained independently from neutron and optical imaging.