Impact of Hydrogen Bleeding into the Cathode Feed of a PEM Fuel Cell. Issue 4 (1st January 2017)

• Record Type: Journal Article
• Authors: Zihrul, Patrick; Weber, Philipp; Durst, Julien; Gasteiger, Hubert A.; Hasché, Frédéric
• Is Part Of: Journal of the Electrochemical Society. Volume 164:Issue 4(2017)
• Page Start: F209
• Page End: F216
• Publication Date: 2017-01-01
• Subjects: chemical membrane stability -- durability -- hydrogen bleed -- hydrogen peroxide formation -- PEM fuel cell; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0161704jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : Hydrogen bleeding into the cathode inlet of a proton exchange membrane (PEM) fuel cell could be a simple approach to reduce the H2 concentration in the fuel cell exhaust during transient operating conditions (e.g., start-up or fast transients) of a PEM fuel cell system; it could also serve as an additional heating source during cold start-up. In this experimental study, we address the question whether the chemical stability of the polymer electrolyte membrane is affected negatively by a hydrogen bleed into the cathode inlet of a PEM fuel cell. First, rotating ring disc electrode (RRDE) experiments were carried out to detect whether any additional H2 O2 is produced during the oxygen reduction reaction in O2 saturated electrolytes in the absence and presence of H2 . Dry open circuit voltage (OCV) experiments were then performed for more than 250 hours in 50 cm 2 single cells at 120°C and 18% relative humidity (RH) in order to investigate the effect of a 4 vol. % H2 -bleed into the cathode inlet on membrane stability. Finally, the distribution of membrane pin-holes was determined on membrane electrode assemblies (MEAs) after the dry OCV tests conducted with or without H2 -bleed using an infrared (IR) camera setup. In addition, the diffusion-limited hydrogen oxidation current on the cathode side was modeled in order to estimate the maximum areal heat flux near the cathode inlet, which would be caused if the H2 oxidation rate were to be diffusion-limited.