Visualization of Membrane Hydration Path in an Operating PEMFC by Nuclei-Labeling MRI

A nuclei-labeling magnetic resonance imaging (NL-MRI) technique was used to investigate the effect of water vapor and generated water on hydration of polymer electrolyte membrane (PEM) separately in polymer electrolyte membrane fuel cell (PEMFC) during operation. It was successfully shown that the membrane hydration path (i.e. anode humidification, cathode humidification or generated water) could be distinguished in an operating PEMFC and the validity and utility of this approach is confirmed by comparing the summation of separation analysis results with conventional MRI result under ordinary fuel cell operation. From visualization results, it was found that water vapor from the anode and the cathode has little effect on the membrane hydration. This indicates that most membrane hydration came from water generated by the electrochemical reaction.