Remarkable progress has been made in reducing the cathodic Pt loading of PEMFCs; however, a huge performance loss appears at high current densities, indicating the existence of a large oxygen transport resistance associated with the ultralow Pt loading catalyst layer. To reduce the Pt loading without sacrificing cell performance, it is essential to illuminate the oxygen transport mechanism in the catalyst layer. Toward this goal, an experimental approach to measure the oxygen transport resistance in catalyst layers is proposed and realized for the first time in this study. The measuring approach involves a dual-layer catalyst layer design, which consists of a dummy catalyst layer and a practical catalyst layer, followed by changing the thickness of dummy layer to respectively quantify the local and bulk resistances via limiting current measurements combined with linear extrapolation. The experimental results clearly reveal that the local resistance dominates the total resistance in the catalyst layer.

中文翻译：

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质子交换膜燃料电池催化剂层中局部和大体输氧阻力的实验测量

在减少PEMFC的阴极Pt负载方面已经取得了显着进展。然而，在高电流密度下出现巨大的性能损失，表明存在与超低Pt负载催化剂层相关的大的输氧阻力。为了在不牺牲电池性能的情况下减少Pt负载，必须阐明催化剂层中的氧气传输机理。为了实现这一目标，本研究首次提出并实现了一种测量催化剂层中氧气输送阻力的实验方法。测量方法涉及双层催化剂层设计，该层由虚拟催化剂层和实际催化剂层组成，然后通过限制电流测量和线性外推来更改虚拟层的厚度，以分别量化局部电阻和体电阻。实验结果清楚地表明，局部电阻支配着催化剂层中的总电阻。