Bulk and interfacial transport properties of porous fuel cell materials

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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.