Effect of through-plane distribution of polytetrafluoroethylene in carbon paper on in-plane gas permeability

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• 作者：Hiroshi Ito ; Katsuya Abe ; Masayoshi Ishida ; Akihiro Nakano ; Tetsuhiko Maeda ; Tetsuo Munakata ; Hironori Nakajima ; Tatsumi Kitahara
• 关键词：Proton exchange membrane fuel cell ; Gas diffusion backing ; Polytetrafluoroethylene ; In-plane permeability
• 刊名：Journal of Power Sources
• 出版年：15 February, 2014
• 年：2014
• 卷：248
• 期：Complete
• 页码：822-830
• 全文大小：1612 K

文摘

In-plane permeability of gas diffusion backing (GDB) of proton exchange membrane fuel cells (PEMFCs) was investigated experimentally. Toray-paper and SGL-paper were selected as GDB test samples. Several Toray-papers were treated in-house with polytetrafluoroethylene (PTFE) using the immersion technique, dried either under atmospheric or vacuum pressure, and then sintered. The dependence of PTFE distribution in the through-plane direction on the PTFE drying conditions was examined using scanning electron microscopy (SEM)-based energy dispersive X-ray spectroscopy (EDS) imaging. The EDS image maps revealed that the PTFE distribution strongly depended on the drying condition, and PTFE drying under vacuum pressure yielded a relatively uniform PTFE distribution. The measured in-plane permeability suggests that the homogeneous distribution of PTFE achieved by the vacuum drying produces a porosity-leveling effect. In addition, the relationship between the in-plane permeability and porosity of the Toray-paper samples followed the Kozeny-Carman relation, whereas due to non-fibrous solids such as binder, that of the SGL-paper samples did not.