Influence of trace oxygen in low-crossover proton exchange membrane fuel cells

• Published in: Journal of power sources 2012-11, Vol.218, p.181-186
• Main Authors: Brooker, R. Paul, Rodgers, Marianne P., Bonville, Leonard J., Kunz, H. Russell, Slattery, Darlene K., Fenton, James M.
• Format: Article
• Language: English
• Subjects: Applied sciences; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Hydrogen crossover; Linear sweep voltammetry; Oxygen reduction; PEM fuel cells
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2012.06.089

The determination of hydrogen permeation through a polymer electrolyte membrane is often achieved through electrochemical methods, under the assumption of no oxygen at the working electrode. However, multiple experiments utilizing low hydrogen crossover conditions have shown reduction currents resulting from trace amounts (2–3 ppm) of oxygen. For conventional membranes, hydrogen crossover is sufficient to overwhelm the trace oxygen, such that the hydrogen permeation results are unaffected. For those conditions with low hydrogen crossover, the presence of trace oxygen can become dominant. This is particularly relevant for advanced polymer electrolyte membranes with very low gas permeability. The use of electrochemical techniques to ascertain the hydrogen permeation coefficient for membranes with low gas permeability was found to be significantly influenced by the presence of trace oxygen. ► Ultra-low H2 crossover showed trace oxygen dominating electrochemical response. ► The effect of scan rate on H2 crossover was examined. ► Electrochemical methods to determine H2 crossover should consider trace oxygen.