质子交换膜燃料电池气体扩散层制备过程材料表征和孔尺度模拟计算

为研究质子交换膜燃料电池（PEMFC）气体扩散层的制备方法对其结构和性能的影响，将聚丙烯腈基碳纤维原纸作为前驱体，以酚醛树脂作为粘结剂，采用热压、碳化、石墨化等工艺制成气体扩散层，考察在原纸浸渍的过程中，不同质量分数酚醛树脂乙醇溶液对气体扩散层结构和性能的影响。利用扫描电子显微镜、汞侵入法、四探针法等进行性能表征，并利用X射线断层扫描技术获得气体扩散层的三维结构，通过孔尺度模拟进行性能计算。结果表明，采用实验表征方法和模拟计算方法可以更加准确和清楚地对气体扩散层性能进行表征，在使用15%质量分数酚醛树脂乙醇溶液浸渍原纸时，可以得到与商用气体扩散层相等的78%孔隙率，同时将电阻率降低了30%左右。

Material characterization and pore-scale simulation of PEMFC gas diffusion layer during its fabrication process

This paper reports the results of an investigation into the effects of fabrication techniques on the structure and performance of a gas diffusion layer (GDL) for proton exchange membrane fuel cells (PEMFC). In the experiment, GDLs were fabricated by hot-pressing, carbonization, and graphitization with polyacrylonitrile-based carbon fiber paper as the precursor and phenolic resin as the adhesive to bind the fibers. The effects of the mass fraction of phenolic resin solution on the structure and properties of GDL were investigated. The GDL microstructure was characterized by scanning electron microscopy, mercury intrusion porosimetry, and four-probe method. The structure of GDL was obtained by X-ray tomography, and pore-scale simulations were performed on the structure. The results show that GDL performance can be quantified accurately via experimental characterization and simulations. It is found that for a raw paper impregnated with 15% mass-fraction phenolic resin solution, a GDL with 78% porosity and 30% reduced resistivity can be obtained compared with commercial GDLs.