Impact of Platinum Loading and Layer Thickness on Cathode Catalyst Degradation in PEM Fuel Cells
Impact of Platinum Loading and Layer Thickness on Cathode Catalyst Degradation in PEM Fuel Cells
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铂负载量和层厚度对 PEM 燃料电池阴极催化剂降解的影响
DOI：
10.1149/1945-7111/acb8df
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发表时间：
2023
影响因子：
3.9
通讯作者：
Zamel, Nada
中科院分区：
文献类型：
--
作者：
Schneider, Patrick;Batool, Mariah;Godoy, Andres O.;Singh, Rajveer;Gerteisen, Dietmar;Jankovic, Jasna;Zamel, Nada
在这项工作中，我们通过全面的原位和STEM-EDS表征研究了铂负载量和层厚度对阴极催化剂降解的影响。为了将铂负载量和层厚度的影响彼此解耦，将实验分为两组，每组的阴极负载量在0.1和0.4 mg Pt cm-2之间变化：（i）具有恒定Pt/C比并因此改变层厚度的样品，以及（ii）具有不同Pt/C比的样品，通过用裸碳稀释来实现，以在不同铂负载量下保持恒定的层厚度。每个MEA经受加速应力测试，其中电池在0.6 V和0.95 V之间操作45，000次循环。无论Pt/C比如何，对于较低的Pt负载量，测量到电化学活性表面积的较高相对损失。STEM-EDS测试结果表明，Pt主要在阴极-膜界面附近被浓度驱动的Pt 2+离子流入膜中而损失。该Pt耗尽区的尺寸已显示出与总Pt负载和层厚度无关，因此在低厚度电极中引起较高的相对Pt损失，因为耗尽区占催化剂层的较大部分。
In this work we investigate the effect of platinum loading and layer thickness on cathode catalyst degradation by a comprehensive in situ and STEM-EDS characterization. To decouple the effect of the platinum loading and layer thickness from each other, the experiments were categorized in two sets, each with cathode loadings varying between 0.1 and 0.4 mg Pt cm− 2:(i) Samples with a constant Pt/C ratio and thus varying layer thickness, and (ii) samples with varying Pt/C ratios, achieved by dilution with bare carbon, to maintain a constant layer thickness at different platinum loadings. Every MEA was subjected to an accelerated stress test, where the cell was operated for 45,000 cycles between 0.6 and 0.95 V. Regardless of the Pt/C ratio, a higher relative loss in electrochemically active surface area was measured for lower Pt loadings. STEM-EDS measurements showed that Pt was mainly lost close to the cathode—membrane interface by the concentration driven Pt 2+ ion flux into the membrane. The size of this Pt-depletion zone has shown to be independent on the overall Pt loading and layer thickness, hence causing higher relative Pt loss in low thickness electrodes, as the depletion zone accounts for a larger fraction of the catalyst layer.