Modeling Proton Exchange Membrane Fuel Cell Cathode Catalyst Layers with the Lattice-Boltzmann-Method Framework
Modeling Proton Exchange Membrane Fuel Cell Cathode Catalyst Layers with the Lattice-Boltzmann-Method Framework
复制标题
使用格子玻尔兹曼方法框架对质子交换膜燃料电池阴极催化剂层进行建模
DOI：
10.1149/09208.0047ecst
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Fuller, Thomas F.
中科院分区：
文献类型：
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作者：
Grunewald, Jonathan B;Goswami, Navneet;Mukherjee, Partha P.;Fuller, Thomas F.
质子交换膜燃料电池（PEMFC）是一种有前途的、不产生二氧化碳的能源转换替代品，有可能极大地改变汽车工业1 -4。然而，除了公共汽车和轻型车辆的小型试验之外，还有一些重大障碍限制了这项技术的广泛应用，例如增加催化活性，减少交叉，降低成本，耐用性等5，6。建模工作的主要重点是解决阴极催化剂层（CCL）的挑战，因为不仅这种薄层使实验表征非常困难，而且还因为氧还原反应（ORR）被认为是常见电化学中最困难的反应。影响PEMFC中CCL研究的主要问题之一是缺乏对失效机制的理解，以及我们在实验研究中的相对困难2，7-9。具体而言，在较高的阴极电位下，铂所依靠的碳载体开始氧化以形成二氧化碳，从而使铂与载体断开8、10。这些高电位还导致铂通过奥斯特瓦尔德熟化而聚集，这大大降低了效率和循环寿命。11，12建模的通常起点是催化剂层的宏观均匀多孔电极模型。为了增加非均相电子转移反应的表面积，使用具有小特征尺寸的多孔电极。与所有燃料电池一样，在这些多孔电极中建立和控制相之间的界面是至关重要的。引入所谓的烧结-团聚体模型，这是一种至少可以追溯到20世纪60年代的理想化，14以更好地表示电极中的复杂结构和过程。然而，随着研究的继续，这种理想化的局限性正在浮出水面;作为一个关键的例子，该模型未能准确预测铂负载对mastransferresistance的影响-它预测没有影响，而实验显示出明显的影响7，15。然而，尽管有这种实验确认，由于电极的复杂结构及其约10微米的轮廓，在操作研究中很难做到。为了解决这个问题，以前的工作提供了深入了解CCL微观结构与FIB-SEM（聚焦离子束扫描电子显微镜），使中尺度建模技术的使用，从这些创建的几何形状的一个例子中显示在图18，16。当前研究的主要目标是在先前的FIB-SEM工作的基础上进行扩展，
Proton exchange membrane fuel cells (PEMFCs) are a promising, non-carbon dioxide producing energy conversion alternative that has the potential to dramatically alter the automotive industry1-4. However, there are significant obstacles that have limited widespread utilization of this technology beyond small trials of busses and light-duty vehicles, such as increasing catalytic activity, reducing crossover, lower cost, durability, among others5, 6. The primary focus of the modeling work addresses the challenges of the cathode catalyst layer (CCL), since not only does this thin layer make experimental characterization extremely difficult, but also because the oxygen reduction reaction (ORR) is considered the most difficult reaction in common electrochemistry. One of the main problems affecting study of the CCL in PEMFCs is the lack of understanding of failure mechanisms and our relative difficulty in experimentally studying them2, 7-9. Specifically, at higher cathode potentials, the carbon support that platinum rests on begins to oxidize to form carbon dioxide, disconnecting the platinum from the support8, 10. These high potentials also cause the platinum to agglomerate by Ostwald ripening, which drastically decreases efficiency and cycle life. 11, 12The usual starting point for modeling has been a macrohomogeneous porous electrode model of the catalyst layer. 13 In order to increase the surface area for heterogeneous electron transfer reactions, porous electrodes with small characteristic dimensions are used. As with all fuel cells, establishing and controlling the interface between phases in these porous electrodes is of paramount importance. The so called flooded-agglomerate model, an idealization that dates back to at least the 1960s, 14 was introduced to represent better the complex structure of and processes in the electrode. As research has continued, however, the limitations of this idealization are surfacing; as a key example, the model fails to accurately predict the effect of platinum loading on masstransfer resistance–it forecasts no effect, whereas experiments show a clear impact7, 15. However, despite this experimental confirmation, due to the complex structure of the electrode and its~ 10-micron profile, it is quite difficult to do in operando studies. To counter this, previous work gives insight into the CCL microstructure with FIB-SEM (focused-ion beam scanning electron microscopy) to enable the use of mesoscale modeling techniques, an example of the geometry created from these is shown in Figure 18, 16. The main objective of the current research is to expand upon the previous FIB-SEM work and