Institute for Fuel Cell Innovation, National Research Council of Canada, Vancouver, BC, Canada.
J Phys Chem B. 2011 Jun 30;115(25):8088-101. doi: 10.1021/jp111400k. Epub 2011 Jun 7.
This work is comprised of a versatile multiscale modeling of carbon corrosion processes in catalyst layers (CLs) of polymer electrolyte fuel cells (PEFCs). Slow rates of electrocatalytic processes in CLs and materials aging are the main sources of voltage loss in PEFCs under realistic operating conditions. We combined microstructure data obtained from coarse-grained molecular dynamics (CGMD) simulations with a detailed description of the nanoscale elementary kinetic processes and electrochemical double-layer effects at the catalyst/electrolyte and carbon/electrolyte interfaces. We exclusively focused on morphology and microstructure changes in the catalyst layer of PEFCs as a result of carbon corrosion. By employing extensive CGMD simulations, we analyzed the microstructure of CLs as a function of carbon loss and in view of ionomer and water morphology, water and ionomer coverage, and overall changes in carbon surface. These ingredients are integrated into a kinetic model, which allows capture of the impact of the structural changes on the PEFC performance decay. In principle, such multiscale simulation studies allow a relation of the aging of CLs to the selection of carbon particles (sizes and wettability), the catalyst loading, and the level of ionomer structural changes during the CL degradation process.
这项工作包含了对聚合物电解质燃料电池（PEFC）催化剂层（CL）中碳腐蚀过程的多功能多尺度建模。在实际操作条件下，CL 中的电催化过程缓慢以及材料老化是 PEFC 电压损失的主要原因。我们结合了从粗粒分子动力学（CGMD）模拟中获得的微观结构数据，以及在催化剂/电解质和碳/电解质界面处对纳米级基本动力学过程和双电层效应的详细描述。我们专门关注由于碳腐蚀而导致的 PEFC 催化剂层中的形态和微观结构变化。通过采用广泛的 CGMD 模拟，我们分析了 CL 的微观结构，作为碳损失的函数，并考虑了离聚物和水的形态、水和离聚物的覆盖范围以及碳表面的整体变化。这些成分被整合到一个动力学模型中，该模型可以捕捉结构变化对 PEFC 性能衰减的影响。原则上，这种多尺度模拟研究可以将 CL 的老化与碳颗粒（尺寸和润湿性）的选择、催化剂负载以及 CL 降解过程中离聚物结构变化的程度联系起来。
