Bulk and interfacial transport properties of porous fuel cell materials

这项研究的目标是通过汽车燃料电池合作组织（AFCC）为燃料电池开发商奔驰和福特提供预测模型和有效参数的量化，这些参数决定了聚合物电解质膜燃料电池（PEMFC）中的热量、质量和电荷的传递。核心组件包括膜、催化剂层和多孔电极（气体扩散层）。当组合形成膜电极组件（MEA）时，这些组件决定了集成燃料电池产品的性能、耐用性和成本。pemfc的性能和耐久性在很大程度上取决于传输过程的调节和有效性，而传输过程又由MEA中每层的结构、几何和表面特性决定。MEA层中多孔微/纳米结构材料的形态复杂性，加上燃料电池操作条件（温度、夹紧压力和相对湿度）的影响，使得原位传输特性的确定成为一个巨大的挑战，在很大程度上仍未解决。在MEA中阐明微观结构和运行条件之间的关系可以降低当前燃料电池设计的成本。我们提出了一种实验-理论策略，该策略集成了所有微观结构，力学和操作方面，以表征和模拟MEA的输运特性，包括体积和界面。目标是：(a)建立对MEA层的微观结构/形态、传输特性、燃料电池性能和实际操作条件和占空比下耐久性之间联系的基本理解；(b)提供准确的本构关系，可用于下一代燃料电池技术的设计、分析和优化。基础知识和工程设计工具也可以扩展到各种可持续能源应用，包括能量转换（燃料电池和电解槽），能量存储（电池和超级电容器），紧凑型热交换器和碳封存技术。

The objectives of the proposed research are to provide fuel cell developers, Mercedes Benz and Ford through Automotive Fuel Cell Cooperation (AFCC), with predictive models and quantification of the effective parameters that determine transfer of heat, mass, and charge in a polymer electrolyte membrane fuel cell (PEMFC). The core components include the membrane, catalyst layer, and porous electrode (gas diffusion layer). When combined to form a membrane-electrode assembly (MEA), these components determine the performance, durability, and cost of integrated fuel cell products. The performance and durability of PEMFCs depend heavily on the regulation and effectiveness of the transport processes, which in turn are determined by structural, geometric, and surface properties of each layer in an MEA. The morphological complexity of the porous, micro/nano-structured materials in the MEA layers, coupled with the effects of fuel cell operating conditions (temperature, clamping pressure, and relative humidity), make determination of in-situ transport properties a tremendous challenge, which, for the most part, remains unresolved. Elucidating the relationships between microstructural and operating conditions in the MEA can reduce the cost of current fuel cell designs.We propose an experimental-theoretical strategy that integrates all microstructural, mechanical, and operational aspects to characterize and model MEA transport properties, both bulk and interfacial. The goals are to: (a) establish a fundamental understanding of the links between microstructure/morphology of the MEA layers, transport properties, fuel cell performance, and durability under actual operating conditions and duty cycles; and (b) provide accurate constitutive relations that can be used with confidence in the design, analysis, and optimization of next-generation fuel cell technology. The fundamental knowledge and engineering design tools can also be extended to a variety of sustainable energy applications, including energy conversion (fuel cells and electrolysers), energy storage (batteries and supercapacitors), compact heat exchangers, and carbon sequestration technologies.