Impact of ionomer resistance in nanofiber-nanoparticle electrodes for ultra-low platinum fuel cells
Impact of ionomer resistance in nanofiber-nanoparticle electrodes for ultra-low platinum fuel cells
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DOI：
10.1016/j.ijhydene.2019.01.083
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发表时间：
2019-03
影响因子：
7.2
通讯作者：
M. Hwang;Y. Elabd
中科院分区：
文献类型：
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作者：
M. Hwang;Y. Elabd
以前，纳米纤维-纳米颗粒电极通过同时电纺和电喷涂(E/E)过程(E/E电极)产生聚合物电解质膜燃料电池，在超低铂(PT)负载(<；0.1mgPtcm−2)下具有高功率密度。在本研究中，在不同Nafion含量下制备了E/E电极，以考察离聚体含量对超低铂负载下催化层传输阻力和燃料电池功率密度的影响。无论Nafion在电喷雾中的含量如何，电子显微镜显示，在E/E电极中，Nafion纳米纤维的直径和催化剂聚集体的颗粒尺寸都是恒定的。因此，与传统电极不同的是，本研究允许在恒定的催化层形态下，独家考察不同离聚体含量下传输阻力对燃料电池性能的影响。在更高的放大倍数下，催化剂聚集体颗粒周围的显微照片发生了明显的变化，其中离聚体薄膜厚度随着离聚体含量的增加而增加。当Nafion的总含量为62wt%时，E/E电极的燃料电池性能最好，催化层阻力最小，这与传统电极(约30wt%)不同。
Previously, nanofiber-nanoparticle electrodes producedviaa simultaneous electrospinning and electrospraying (E/E) process (E/E electrodes) resulted in polymer electrolyte membrane fuel cells with high power densities at ultra-low platinum (Pt) loadings (<0.1 mgPtcm−2). In this study, E/E electrodes were fabricated at various Nafion contents to investigate the impact of ionomer content on catalyst layer transport resistances and fuel cell power density at ultra-low Pt loadings. Regardless of the Nafion content in the electrospray, the Nafion nanofiber diameters and catalyst aggregate particle sizes are constant in the E/E electrodes evidenced by electron microscopy. Therefore, this study allows for the exclusive investigation of the effect of transport resistances on fuel cell performances at different ionomer contents at a constant catalyst layer morphology, which differs from conventional electrodes. At higher magnifications, changes are evident in the micrographs around the catalyst aggregate particles, where an increase in ionomer thin film thickness is observed with increasing ionomer content. The maximum fuel cell performance and a minimum in catalyst layer resistance for E/E electrodes is observed at a total Nafion content of 62 wt%, which differs from conventional electrodes (ca. 30 wt%).