Nafion membranes with a porous surface

Title
Nafion membranes with a porous surface
Authors
당 쿠옥 칸헨켄스마이어디억N. Nambi Krishnan장종현김형준남석우임태훈
Keywords
Nafion membranes; Porous surfaces; Hierarchical structures; Water management; Fuel cells
Issue Date
2014-06
Publisher
Journal of membrane science
Citation
VOL 460, 199-205
Abstract
Nafion membranes with a monolayer of pores on one surface (P-Nafion) were prepared by casting a Nafion SE20092 dispersion containing ortho-dichlorobenzene. The pores are not connected but provide 2 μm large openings, increasing the membrane surface by one dimension. The thickness of the porous layer is typically <5 μm. In catalyst coated membranes the catalyst layer penetrated the pores well. The effect on the performance of a polymer electrolyte fuel cell (PEFC) was investigated at 95 °C. The porous layer formed the cathode, to enhance water back diffusion. After 24 h equilibration, 30&#8211;35 μm thick P-Nafion gave 10&#8211;16% higher current density, reaching 858 mA/cm2 at 0.4 V and 50% rh. N211 and P-Nafion equilibrated for 8 min showed peak power densities of 56 and 208 mW/㎠ under anhydrous conditions, respectively, indicating that drying processes are slowed down. The stability of a MEA was tested for 240 h at 0.4 V and 50% rh (anode/cathode), without observable degradation. Under fully humidified conditions, the electrochemical surface area (ECSA) increased 40% in comparison to a N211 based MEA. At 65 °C, the ECSA more than doubled, showing 141 ㎡/g Pt. Also influence of the pores on water transport through a membrane and stability against membrane&#8211;electrode delamination were considered.
URI
http://pubs.kist.re.kr/handle/201004/47377
ISSN
03767388
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KIST Publication > Article
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