Characterization of nanoporous catalyst layers for PEMFCs

燃料电池是唯一能够直接取代目前汽车上使用的内燃机的现有技术。 它们提供相当的范围，功率，加油时间，性能和可靠性。 商业化的主要技术障碍是由于在所谓的催化剂层（CL）中使用昂贵的铂作为电催化剂，它们的成本相对较高。因此，设计使用更少铂的燃料电池是使燃料电池与世纪的旧内燃机技术在成本上具有竞争力的关键一步。 这项工作的目的是开发工具来测量设计优化的燃料电池所需的各种工程参数。 处理CL时的主要挑战是所涉及的规模。 CL是约10微米厚的多孔层，由碳-铂纳米颗粒组成，通过离子传导聚合物材料的网络聚集在一起，与50-500 nm孔的多孔网络相互渗透。 在这个项目中，将开发能够测量或研究（a）通过碳-铂颗粒的交联网络的电子电导率，（B）离聚物网络的离子电导率，（c）孔隙网络的孔径分布和连通性，以及（d）孔隙中的流体渗透性的工具。 该实验工具同时提供了这些纳米多孔材料的关键结构和传输参数。 这些测试提供的信息最终将允许对每个阶段的配置进行独立的优化，同时了解一个领域中的任何变化对其他领域的影响。

Fuel cells are the only existing technology capable of directly replacing the internal combustion engine currently used on automobiles. They offer comparable range, power, refueling times, performance and reliability. The main technical barrier to commercialization is their relatively high cost owing to the use of expensive platinum as an electrocatalyst in the so-called catalyst layer (CL). Designing fuel cells to use less platinum is therefore a key step in making fuel cell cost-competitive with the century old internal combustion technology. The aim of this work is to develop tools to measure the various engineering parameters necessary to design an optimized fuel cell. The main challenge when dealing with CLs is the size-scales involved. CLs are a porous layer approximately 10 microns thick, composed carbon-platinum nano-particles, agglomerated together by a network of ion conducting polymer material, interpenetrated with a porous network of 50-500 nm pores. In this project, tools will be developed that can measure or study (a) the electronic conductivity through the percolating network of carbon-platinum particles, (b) the ionic conductivity of the ionomer network, (c) the pore size distribution and connectivity of the void network and (d) the fluid permeability in the pore space. This experimental tools on this list simultaneously provide key structural and transport parameters of these nano-porous materials. The information furnished by these tests will finally allow an independent optimization of the configuration of each phase, while understanding the impact any changes in one realm have on the others.