Effectiveness of Air-Bleeding on the CO Tolerance Improvement of High Temperature Proton Exchange Membrane Fuel Cells

Fuel cell technologies are eco-friendly, and thus they are developed to reach the global goal of net-zero carbon emissions. To increase the fuel cell CO tolerance and simplify purification processes of reformate fuel cell systems, the reformate high-temperature proton exchange membrane fuel cell (HTPEMFC) becomes one of the promising solutions. In this research, the effectiveness of air-bleeding on the CO tolerance improvement of HTPEMFCs is studied. The voltage signal-to-noise ratio (SNR) and electrochemical impedance spectroscopy analysis indicate that air-bleeding suppresses the CO poisoning reaction, reduces the poisoning intensity, and improves the stability of the HTPEMFC performance. The air-bleeding concentration for the HTPEMFC between 140-180 degrees C with CO of less than 5% is suggested to be 1-1.5%, because excess air does not enhance its effectiveness. The SNR analysis as well indicates that the working temperature and H-2 concentration affect the CO poisoning intensity more significantly than the air-bleeding concentration.