SGER: Optimized Catalyst Layer Structure for PEM Fuel Cells

催化剂层是质子交换膜燃料电池中最重要的组成部分，是电池的发电元件。 这是一个所有三个重要阶段必须结合在一起，使发电反应发生的区域。目前，PEM燃料电池中的催化剂层由碳载体上的铂、Nafion离聚物和Teflon制成。固体Pt/C催化剂相用作阳极和阴极处的氢氧化或氧还原反应的电催化剂，并提供往返于反应位点的电子传导。Nafion离子相提供离子传导性或质子迁移到膜电解质和从膜电解质迁移的路径，并充当催化剂颗粒的粘合剂。特氟隆产生疏水气体区域，用于将反应物气体输送到催化剂层内的催化剂表面和从催化剂表面输送。 为了在PEM燃料电池中实现高性能，必须使PEM燃料电池中电压损失的三个主要来源（活化、欧姆和传输）最小化。 可以通过增加电活性催化剂表面积来减少由于催化剂层中的活化电阻而引起的电压损失。通过提高催化剂层中的离子和电子传导性，可以减少由于欧姆电阻引起的电压损失。最后，可以通过最小化发生最慢传输过程的区域（Nafion膜）的厚度和最小化反应物往返于催化剂表面的传输过程的障碍（如液态水）来降低由于质量传输引起的电压损失。 该提出的方法的智力优点是其能够产生具有良好限定和控制的结构的催化剂层，所述结构是满足在如上所述的PEM燃料电池中实现高性能所需的要求所必需的。 如果这一过程成功，它将导致膜和电极组件以及具有上级性能的燃料电池。 这项工作的更广泛的影响是，燃料电池的使用将有助于减少环境问题和美国。对外国石油的依赖。因此，提高其性能的技术将提高其竞争力，并有助于加速这项技术的商业化。 此外，本文开发的工艺也可用于为其他电化学应用中使用的电极创建理想的催化剂层结构。

The catalyst layer, being the power-producing component, is considered as the most important component in a PEM fuel cell. It is a region where all three important phases must be brought together to enable the power generating reactions to occur. Currently, the catalyst layers in a PEM fuel cell are made of platinum on carbon support, Nafion ionomer and Teflon. The solid Pt/C catalyst phase acts as the electro-catalyst for the hydrogen oxidation or oxygen reduction reactions at the anode and cathode and provides electronic conduction to and from the reactive sites. The Nafion ionic phase provides the ionic conductivity or pathways for the protons to migrate to and from the membrane electrolyte and acts as a binder for the catalyst particles. Teflon creates the hydrophobic gas region for reactant gas transport to and from the catalyst surface within the catalyst layers. To achieve high performance in a PEM fuel cell, the three major sources of voltage loss (activation, ohmic and transport) in a PEM fuel cell must be minimized. The voltage loss due to the activation resistance in the catalyst layer can be reduced by increasing the electro-active catalyst surface area. The voltage loss due to the ohmic resistance can be reduced by increasing the ionic and electronic conduction in the catalyst layer. Finally, the voltage loss due mass transport can be reduced by minimizing the thickness of the region through which the slowest transport process occurs (Nafion film) and minimizing the barriers (like liquid water) to the transport processes of reactants to and from the catalyst surface. The intellectual merit of this proposed process is its ability to create a catalyst layer with well-defined and controlled structure necessary to satisfy the requirements needed to achieve high performance in a PEM fuel cell as described above. If this process is successful, it will result in membrane and electrode assemblies and fuel cells with superior performance. The broader impacts of this work are that the use of fuel cells will help reduce environmental problems and the U.S.'s dependence on foreign oil. Consequently, technology that increases its performance will increase its competitiveness and help accelerate the commercialization of this technology. Furthermore, the process developed here could also be used to create ideal catalyst layer structures for electrodes used in other electrochemical applications.