Experimental Investigation and Discussion on the Mechanical Endurance Limit of Nafion Membrane Used in Proton Exchange Membrane Fuel Cell

Abstract

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 performances of PEMFCs are far from achieving the target from the Department of Energy (DOE). Thus, 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 OPEN ACCESSEnergies 2014, 7 6402 different cycling times and wide humidity ranges. The tensile tests are repeated for both kinds of specimens to assess the strain-stress relations. Furthermore, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and Scanning electron microscope (SEM) observation and water absorption measurement were conducted to speculate the cause of this variation. The initial cracks along with the increasing of bound water content were speculated as the primary cause.

State of the art and prospects in the development of proton‐conducting perfluorinated membranes with short side chains: A review

“…The copolymer for Nafion was obtained by copolymerization of tetrafluoroethylene (TFE) with fluorocarbon vinyl ether with a sulfonyl fluoride group. Nafion membranes demonstrated excellent characteristics; these materials are still used in various fields 9‐11 . However, they can be included only in PEMFC operating at temperatures below 90°C.…”

Shielded goethite catalyst that enables fast water dissociation in bipolar membranes

“…Beginning from the XRD spectrum of pristine Nafion-CEL ( Supplementary Fig. 2), which exhibits two wide XRD bands at 2θ degrees of 16.7 and 38.8, represent the Nafion material 18 . XRD spectrum of the pre-PANI shield (Fig.…”

Adhesion of Nafion for advanced proton exchange membrane fuel cell architectures under low fabrication temperature

“…The aim of uniaxial tensile test is to assess viscoelasticviscoplastic properties [18,19]. Nafion membrane samples were sized according to the ASTM standard D638-2a, type V [23], as shown in Figure 2.…”

“…Hence, we aim to gain better understanding of the structural aspects of the TFFC and thus to enable fabrication of a robust fuel cell. Although mechanical behavior has been researched, most of the Nafion characterization literature is on bulk properties [11,14,[16][17][18][19] and thermal behavior [7,8,13,20]. Consequently, appropriate materials characterization techniques relevant to the fuel cell structure need to be adopted, in some cases, for the first time in the study of Nafion.…”