The commercial deployment of polymer electrolyte fuel cells (PEFCs) hinges on breakthroughs in design and integration of highly performing and durable catalyst layers with markedly reduced platinum loading. Experimental studies have shown an unexpected increase in voltage losses upon a drastic reduction in the Pt content. In an effort to unravel this peculiar behavior, an existing physical model of catalyst layers in PEFCs is employed to analyze a wide range of fuel cell performance data from the literature. The analysis reveals correlated trends in key fuel cell parameters. These findings can be explained in view of the tipping water balance that affects the interplay of transport and reaction in catalyst layer and gas diffusion media. This represents a compelling alternative to the widespread ionomer-film hypothesis that links observed power losses at low Pt loading to a mesoscopic oxygen transport resistance. The presented theoretical analysis warrants the definition of a correlation exponent that should find use in assessing the merit of different approaches in catalyst layer fabrication.

中文翻译：

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改善聚合物电解质燃料电池中的水平衡和Pt负载效应：基于模型的分析†

聚合物电解质燃料电池（PEFC）的商业部署取决于高性能和耐用性催化剂层的设计和集成方面的突破，同时铂的负载量显着降低。实验研究表明，随着Pt含量的急剧降低，电压损失会意外增加。为了阐明这种特殊行为，采用了PEFC中催化剂层的现有物理模型来分析来自文献的各种燃料电池性能数据。该分析揭示了关键燃料电池参数的相关趋势。可以考虑倾倒水平衡来解释这些发现，该倾倒水平衡影响催化剂层和气体扩散介质中的输送和反应的相互作用。这代表了广泛的离聚物-膜假说的一种令人信服的替代方法，该假说将低Pt负载下观察到的功率损失与介观的氧气传输阻力联系在一起。提出的理论分析保证了相关指数的定义，该指数应可用于评估催化剂层制造中不同方法的优点。