Simultaneous visualization of oxygen distribution and water blockages in an operating triple-serpentine polymer electrolyte fuel cell

▶ Dye film was used to visualize PO2 and water blockages in flow channels of a PEFC. ▶ Water droplets in a gas-flow channel lowered PO2 in the blocked channel. ▶ Air was supplied through the GDL to the channel blocked by water droplets. ▶ Under the blocked channel, water formed by power generation was accumulated. ▶ Flooding of catalyst and/or porous layers lowered the power generation.