Effect of ionomer content and relative humidity on polymer electrolyte membrane fuel cell (PEMFC) performance of membrane-electrode assemblies (MEAs) prepared by decal transfer method
✍ Scribed by Sunyeol Jeon; Jisun Lee; Gema M. Rios; Hyoung-Juhn Kim; Sang-Yeop Lee; EunAe Cho; Tae-Hoon Lim; Jong Hyun Jang
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 768 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0360-3199
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✦ Synopsis
Membrane-electrode assemblies (MEAs) were fabricated by the decal transfer method with various Nafion ionomer contents (10e40 wt%) and their single cell performance and electrochemical characteristics were examined in atmospheric air at relative humidities of 25e95%. At high humidity (95%), the MEA performance was the highest with a cathode ionomer content of 30 and 20 wt% at 0.6 and 0.4 V, respectively. The optimum ionomer content of the decal MEAs increased with decreasing humidity, because of the change in the oxygen transport rate (water flooding) and number of active sites (ionic resistance). The concentration overpotential gradually increased with relative humidity up to about 0.4 V at 0.8 A/cm 2 , which was not considered in previous studies using pressurized air and oxygen.
The combined effect of the electrochemical active surface area and ionic resistance of the cathodes on the activation overpotential was also investigated, focusing on intermediate and low humidity levels, using a newly developed impedance analysis method.