The lifetime issues caused by catalyst degradation is one of the most critical challenges for the commercial application of proton exchange membrane fuel cells. However, the understanding concerning the interactions among transport, reaction, and catalyst degradation is inadequate for further durability enhancement. Herein, a scale-bridging model that couples a cell-scaled model to reveal the reactive transport process and a catalyst-scaled model to unveil Pt degradation is proposed to capture the degradation characteristics. It is found that the heterogeneous aging is observed in both the through-plane and channel-rib directions due to the enhanced mass loss near the membrane and the water accumulation under the rib, resulting in the mitigation of the core reaction region away from the membrane, thereby causing an increase in ohmic loss after cycles. More importantly, the local oxygen transport resistance increases with degradation, leading to a remarkable cell performance loss under high current density. Additionally, the influences of cell voltage load and inlet humidity on Pt degradation are also investigated. And the proposed gradient catalyst layer shows a significant mitigating effect on Pt degradation. This work reveals the degradation-performance interactions, which is conducive to design the high-performance fuel cell to prolong lifetime.

中文翻译：

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质子交换膜燃料电池的尺度桥接模型：了解多物理传输、电化学反应和异质老化之间的相互作用


催化剂降解引起的寿命问题是质子交换膜燃料电池商业应用最关键的挑战之一。然而，对传输、反应和催化剂降解之间相互作用的理解不足以进一步提高耐久性。在此，提出了一种尺度桥接模型，该模型将揭示反应传输过程的细胞尺度模型和揭示 Pt 降解的催化剂尺度模型结合起来，以捕获降解特征。研究发现，由于膜附近的质量损失增加以及肋下方的水积聚，在穿过平面和通道肋方向上都观察到了非均质老化，导致远离膜的核心反应区域减轻，从而导致循环后欧姆损耗增加。更重要的是，局部氧传输阻力随着降解而增加，导致高电流密度下电池性能显着损失。此外，还研究了电池电压负载和入口湿度对 Pt 降解的影响。所提出的梯度催化剂层对 Pt 降解具有显着的缓解作用。这项工作揭示了退化与性能的相互作用，有利于设计高性能燃料电池以延长寿命。