SGER: Optimized Catalyst Layer Structure for PEM Fuel Cells

催化剂层是PEM燃料电池中最重要的组成部分，是产生电能的组成部分。在这个地区，所有三个重要阶段必须结合在一起，才能使发电反应发生。目前，质子交换膜燃料电池的催化剂层是由碳载体上的铂、钠离子和聚四氟乙烯制成的。固体Pt/C催化剂相在阳极和阴极充当氢氧化或氧还原反应的电催化剂，并在反应位点之间提供电子传导。Nafion离子相提供离子导电性或质子进出膜电解质的途径，并作为催化剂颗粒的粘合剂。聚四氟乙烯产生疏水气体区域，用于在催化剂层内从催化剂表面输送反应物气体。为了在PEM燃料电池中实现高性能，必须最小化PEM燃料电池中的三个主要电压损耗源（激活、欧姆和输运）。通过增加电活性催化剂的表面积，可以降低催化剂层中活化电阻引起的电压损失。由于欧姆电阻的电压损失可以通过增加催化剂层中的离子和电子传导来降低。最后，通过最小化最慢传输过程发生的区域（Nafion膜）的厚度和最小化反应物进出催化剂表面传输过程的障碍（如液态水），可以减少由于质量传输引起的电压损失。该工艺的智力优势在于它能够创建具有良好定义和可控结构的催化剂层，以满足上述PEM燃料电池中实现高性能所需的要求。如果这个过程是成功的，它将导致膜和电极组件和燃料电池具有优越的性能。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中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，并有助于加速该技术的商业化。此外，这里开发的工艺也可以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.