In situ observation of the water distribution across a PEFC using high resolution neutron radiography

The water distribution across the membrane electrolyte assembly (MEA) of a working polymer electrolyte fuel cell (PEFC) was observed in situ using neutron radiography. In order to resolve the distribution between the different layers of the MEA, in plane imaging (cell membrane parallel to the beam) was used. Unprecedented spatial resolution for neutron radiography was obtained using a new detector system available at PSI combined with specific anisotropic resolution enhancement methods. A detrimental effect on performance of excessive water content in the cathode GDL was observed. Depending on the operating condition, a strong separation of the water content between ribs and channel was observed, particularly in the cathode GDL.