Soft X-ray visualization of the liquid water transport within the cracks of micro porous layer in PEMFC
Soft X-ray visualization of the liquid water transport within the cracks of micro porous layer in PEMFC
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DOI：
10.1016/j.elecom.2011.03.033
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发表时间：
2011-06
影响因子：
5.4
通讯作者：
T. Sasabe;P. Deevanhxay;S. Tsushima;S. Hirai
中科院分区：
文献类型：
--
作者：
T. Sasabe;P. Deevanhxay;S. Tsushima;S. Hirai
为了研究质子交换膜层上的裂纹对液态水传输的影响，采用实验室软X射线照相技术对运行中的质子交换膜燃料电池中的液态水行为进行了横截面成像（细胞膜平行于梁）.可视化的空间和时间分辨率分别为0.5 μ m和2 s/帧。使用带有裂纹MPL的碳布GDL，并且PEMFC的每一层和MPL上的裂纹都清晰可见。结果清楚地表明，液态水主要通过MPL上的裂纹流向基底层，并且在MPL中没有观察到液态水。因为MPL是高度疏水的，所以MPL可以限制液态水进入基底层。另一方面，液态水倾向于储存在CL和MPL之间的界面中。这些结果表明，MPL上的较大的孔（如裂纹）的功能作为液态水的通道到基板层，和MPL上的较小的孔的功能作为气体的传输路径，和MPL的表面形态可能会影响液态水在PEMFC中的传输。
In order to investigate the effect of the cracks on the MPL on liquid water transport, the cross-sectional imaging (cell membrane parallel to the beam) of liquid water behavior in the operating PEMFC was carried out by laboratory-based soft X-ray radiography technique. The spatial and temporal resolutions of the visualization were 0.5 um and 2 s/frame, respectively. The carbon cloth GDLs with the cracked MPL were used and each layer of the PEMFC and the crack on the MPL were clearly visualized. The results clearly showed that the liquid water mainly flows through the crack on the MPL to the substrate layer, and no liquid water was observed in the MPL. Because the MPL is highly hydrophobic, the MPL can limit the liquid water access to the substrate layer. On the other hand, liquid water tends to be stored in the interface between the CL and the MPL. These results suggest that the larger pores (e.g. cracks) on the MPL function as the liquid water pathway to the substrate layer, and the smaller pores on the MPL function as the gas transport path, and the surface morphology of the MPL might affect the liquid water transport in the PEMFC.