Nanomanufacturing of Three-Dimensional Nanofiber-Nanoparticle Electrodes for Ultra-low Platinum Fuel Cells

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Today, electric vehicles are the only zero-emission vehicle option. They are either fuel cell and battery-powered. Fuel cells have key advantages over batteries for vehicles with 300-mile driving range, e.g., 6-times higher specific energies (i.e., lower weight-to-power ratio), 6-times lower energy storage (i.e., lower fuel weight), and rapid re-fueling times (i.e., shorter recharge times). Although automakers have engineered solutions to many of the major hurdles to bringing the fuel cell vehicle to the market place, the high cost due to the required precious metal platinum electrodes is a major factor that has limited their mass commercialization. This award investigates the manufacturing of unique nanofiber-nanoparticle fuel cell electrodes, the nanomaterial-electrochemical relationships in these electrodes and their subsequent impact on fuel cell performance. This project establishes a fundamental understanding of designing optimal advanced nanostructured electrodes for fuel cells that significantly lowers the required platinum and therefore lowers their cost. This research provides pathways to mass commercialization of efficient low-cost fuel cells, which can have significant impact on society, where fuel cells will provide alternative energy at a lower environmental cost not only for automobiles, but for stationary power as well. The project's comprehensive experimental and modeling approach to understand the design and functioning of nanostructured electrodes has a significant impact on nanomanufacturing and electrochemical engineering. Outreach and education activities consist of involving K-12 students in fuel cell module technology and recruiting and training underrepresented undergraduate students in the laboratory.The overall goal of this project is to manufacture electrodes with advanced nanoscale morphologies and understand the impact of morphology on multiple simultaneous reaction/transport phenomena to generate fuel cell energy at higher efficiencies and lower costs. The specific objective is to nanomanufacture new controllable, well-organized three-dimensional (3D) nanofiber-nanoparticle electrodes that exhibit optimal fuel cell performance at ultra-low platinum contents. These new three-dimensional nanostructured electrodes are manufactured via a new process, needleless electrospinning/electrospraying with template-assisted nanofiber collection. A new three-dimensional fuel cell model is also developed to predict fuel cell performance with three-dimensional nanofiber-nanoparticle electrodes to guide in electrode nanomanufacturing. Accurate model parameters are obtained through a comprehensive set of advanced in situ and ex situ experimental techniques that are utilized to carefully characterize and analyze the 3D electrode morphology, electrochemical reaction rates, and transport properties. The new process produces fuel cell electrodes with advanced nanoscale morphologies that overcome previous shortcomings of severe transport and reaction limitations in low platinum loaded conventional fuel cell electrodes.