This one-year exploratory research project proposes to develop a new family of carbon-aerogel-based nanomaterials for use as electrodes in high-performance proton exchange membrane (PEM) fuel cell power sources. The proposed materials consist of electrically conductive mesoporous carbon aerogel supports having internal porosity of nanoscopic dimensions, with fluorinated polymeric electrolytes grafted onto the interior surface of the aerogel mesopores. The high surface area and high porosity of aerogel materials are desirable in fuel cell electrodes because they allow for dispersion of a maximum amount of catalyst particles per unit volume of support while also providing sufficient physical structure in the support to allow for access of fluoropolymer electrolyte to catalyst particles without also blocking transport of fuel, oxidant, and water to and from catalyst particles. Fluorinated electrolytes are essential in fuel cell electrodes because only fluorinated materials can provide the needed long-term chemical stability for a practical device. Grafting of fluoropolymer electrolytes inside of carbon aerogel mesopores has never been attempted but will be essential to operation of a PEM fuel cell electrode since it offers the only means for making robust electrodes that provide for electrolyte access to catalyst particles anchored inside the aerogel mesopores. Electrode materials designed with these considerations in mind are expected to exhibit maximum activity for fuel cell reactions (e.g., electrochemical oxygen reduction, hydrogen oxidation, methanol oxidation) and could form the basis of a new generation of power sources exhibiting much higher performance than existing devices.
The specific scientific objectives of the proposed research are twofold: (1) explore methods for synthesizing carbon aerogels with grafted fluoropolymer electrolytes and dispersed nanoparticulate catalysts in the pores, with particular focus on methods amenable to eventual high-volume manufacturing; and (2) characterize the resulting materials to demonstrate their potential utility in PEM fuel cell technology. In addition to the interdisciplinary training of graduate students, this project will have broad impacts in several areas of importance to the national interest. It will contribute to making more effective utilization of energy resources, minimizing long-term environmental problems associated with depletion of fossil fuels, helping to make more viable a sustainable energy economy based on hydrogen gas as an energy carrier, and helping to make our nation more secure by providing our military forces with more options for lightweight portable electric power.
