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Experimental Investigation on the Mechanical Endurance Limit of Nafion membrane used in Proton Exchange Membrane Fuel Cell
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1  Inha University

Abstract: Nowadays, two pressing problems face the world: the energy crisis and environmental pollution. As a solution of high efficiency and clean energy, fuel cell technologies, especially proton exchange membrane fuel cell (PEMFC), have caught extensive attention. However, after decades of development, the word-wide commercialization of PEMFC has not started properly yet; due mainly to the barriers of high cost and durability. These days, the performances of PEMFCs are far from achieving the target from the Department of Energy (DOE). So, further understanding of the degradation mechanism is needed to overcome this obstacle. Due to the importance of proton exchange membrane in a PEMFC, the degradation of the membrane, such as hygrothermal aging effect on its properties, are particularly necessary. In this work, a thick membrane (Nafion N117) which is always used as an ionic polymer for the PEMFCs has been analyzed. Experimental investigation is performed for understanding the mechanical endurance of the bare membranes under different loading conditions. Tensile tests are conducted to compare the mechanical property evolution of two kinds of bare-membrane specimens including the dog-bone and the deeply double edge notched (DDEN) types. Both dog-bone and DDEN specimens were subjected to a series of degradation tests with different cycling times and wide humidity ranges. The tensile tests are repeated for both kinds of specimens to assess the strain-stress relations. Furthermore, the yielding stresses were obtained, as well as the work of fracture.
Keywords: PEMFC, Nafion, fracture test, tensile test, hygrothermal aging, Mechanical Endurance.
Comments on this paper
Teresa J. Leo
Paper by Xiao, Wendling and Cho
The mechanical endurance study on Nafion 117 membrane is an interesting topic since direct methanol fuel cells (DMFC) usually include the membrane-electrodes assembly (MEA) fabricated with this polymeric membrane. As known, the main applications of DMFC are found in the portable devices area, therefore it is very important to investigate degradation features of Nafion 117. The temperature value investigated in this work is 25 ºC and it would be quite interesting to compare experiments performed at temperature values higher than 25 ºC since DMFCs improve their performance at higher temperatures.

The authors of the full paper are: Yang. Xiao, Loïc. Wendling, Kumar K. Poornesh, and Chongdu Cho. Nevertheless in Cite this article it appears Xiao; Wendlind and Cho.
Teresa J. Leo
Yang Xiao
Thank you very much for the comments. The investigation of temperature effect on the mechanical behavior of Nafion membranes will be conducted in the future. The degradation features according to the number/time of aging treatment will be investigate as well.