Polymer electrolyte membrane fuel cells (PEMFCs) are a promising and sustainable alternative to internal combustion engines for automotive applications. Polymeric perfluorosulfonic acid (PFSA) plays a key role in PEMFCs as a proton conductor in the anode and cathode catalyst layers and in the electrolyte membrane. In this study, spectroscopic scanning coherent diffraction imaging (spectro-ptychography) and spectro-ptychographic tomography were used to quantitatively image PFSA ionomers in PEMFC cathodes in both two and three dimensions. We verify that soft X-ray ptychography gives significant spatial resolution improvement on soft matter polymeric materials. A two-dimensional spatial resolution of better than 15 nm was achieved. With better detectors and brighter and more coherent X-ray beams, radiation-sensitive PFSA ionomers will be visualized with acceptable levels of chemical and structural modification. This work is a step toward visualization of ionomers in PEMFC cathodes at high spatial resolution (presently sub-15 nm, but ultimately below 10 nm), which will be transformative with respect to optimization of PEMFCs for automotive use.

中文翻译：

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聚合物电解质膜燃料电池阴极层的高分辨率X射线光谱分析

聚合物电解质膜燃料电池（PEMFC）是汽车应用中内燃机的有前途且可持续的替代品。聚合全氟磺酸（PFSA）在PEMFC中作为阳极和阴极催化剂层以及电解质膜中的质子导体发挥着关键作用。在这项研究中，使用光谱扫描相干衍射成像（光谱分析）和光谱分析层析成像技术对PEMFC阴极中的PFSA离聚物在二维和三维上进行定量成像。我们验证了软X射线刻印技术可以显着改善软质聚合物材料的空间分辨率。获得了优于15 nm的二维空间分辨率。有了更好的探测器和更明亮，更连贯的X射线束，辐射敏感的PFSA离聚物将以可接受的化学和结构修饰水平可视化。这项工作是朝着以高空间分辨率（目前低于15 nm，但最终低于10 nm）可视化PEMFC阴极中的离聚物迈出的一步，这对于汽车用PEMFC的优化将具有变革性。