Isolation of Transport Mechanisms in PEFCs with High Resolution Neutron Imaging

Cell water balance and anode to cathode water transport were investigated using high resolution neutron radiography in the through-plane direction. Induced pressure and relative humidity gradients were imposed across the membrane electrode assembly to determine how these gradients alter saturation profiles in the diffusion media. The asymmetric anode/cathode channel pitch used in this study resulted in large anode water saturation changes with applied gradients while cathode saturation remained more constant. A new low-cost core-shell diffusion media is introduced as a potential replacement of current diffusion media. This new material was found to reduce overall cell water content, but suffers poor overall performance due to excessive ohmic losses, and more work is needed to develop this concept.