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

• Published in: Journal of power sources 2011-03, Vol.196 (5), p.2635-2639
• Main Authors: Takada, Kenji, Ishigami, Yuta, Inukai, Junji, Nagumo, Yuzo, Takano, Hiroshi, Nishide, Hiroyuki, Watanabe, Masahiro
• Format: Article
• Language: English
• Subjects: Applied sciences; Blocking; Catalysts; Channels; Direct energy conversion and energy accumulation; Droplets; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrolytes; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Flooding; Fuel Cell; Fuel cells; Gas diffusion layer; Oxygen partial pressure; Partial pressure; Porphyrin; Simultaneous visualization; Visualization
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2010.10.097

[Display omitted] ▶ 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. Visualization inside polymer electrolyte fuel cells (PEFCs) is important for elucidating reaction distributions to improve the performance and durability of the cells. An O2-sensitive porphyrin luminescent dye film was used to visualize oxygen partial pressures and water blockages simultaneously in triple-serpentine gas flow channels in an operating PEFC. Water droplets formed near the exit of a gas-flow channel lowered the oxygen partial pressure noticeably over the channel by blocking air flow near the entrance. Meanwhile, air was continuously supplied from the other channels through the gas diffusion layer, thus allowing power to be generated in the blocked channel. With water blockages, however, the catalyst layer under the channel became flooded by the water produced during the reaction, and the flooded state continued to exist in the catalyst and/or porous layers, even after blowing the water droplet out, so that the power generation was lowered along the channel.