X-ray Imaging of Water Distribution in Cathode Electrode of PEFC and Control of Liquid Water Transport by Electrode Perforation

Abstract

To alleviate water flooding in cathode electrodes of polymer electrolyte fuel cells (PEFCs), the modified electrode/channel structure with electrode perforation and channel hydrophilization has been proposed. This study investigated the liquid water distribution in the modified electrode with penetration grooves of an operating PEFC using X-ray imaging, and evaluated the effect of groove size on the water removal inside the electrode. The influence of the combinational electrode/channel structure on the cell performance was also demonstrated by the constant-current operation test. It was noted that the electrode perforation effectively reduces the water accumulation in the cathode GDL. An increase in the groove width enhances the in-plane water discharge towards the large groove. The combinational structure with electrode perforation and channel hydrophilization improves the limiting current density due to the positive through-plane water removal from the porous media to the flow channel.