NER: New Fuel Cell Electrodes from Carbon Aerogels with Internally Grafted Fluoropolymer Electrolytes

这项为期一年的探索性研究计划开发一系列新的碳气凝胶纳米材料，用作高性能质子交换膜(PEM)燃料电池电源的电极。所提出的材料包括具有纳米尺寸的内部孔隙率的导电介孔碳气凝胶载体，以及在气凝胶介孔内表面接枝的氟化聚合物电解质。高比表面积和高孔隙率的气凝胶材料在燃料电池电极中是可取的，因为它们允许在每单位载体体积中分散最大数量的催化剂颗粒，同时还在载体中提供足够的物理结构，以允许氟聚合物电解质进入催化剂颗粒，而不会阻碍燃料、氧化剂和水往返催化剂颗粒的运输。氟化电解液在燃料电池电极中是必不可少的，因为只有氟化材料才能为实际装置提供所需的长期化学稳定性。在碳气凝胶介孔内嫁接氟聚合物电解质从来没有被尝试过，但对于PEM燃料电池电极的运行将是必不可少的，因为它提供了制造坚固电极的唯一手段，该电极为固定在气凝胶介孔内的催化剂颗粒提供了电解液通道。根据这些考虑设计的电极材料有望在燃料电池反应(如电化学氧还原、氢氧化、甲醇氧化)中表现出最大的活性，并可能形成新一代电源的基础，表现出比现有设备更高的性能。拟议研究的具体科学目标有两个：(1)探索在孔道中接枝氟聚合物电解质和分散的纳米颗粒催化剂合成碳气凝胶的方法，特别是能够最终大规模制造的方法；以及(2)表征所得到的材料，以展示其在PEM燃料电池技术中的潜在用途。除了对研究生进行跨学科培训外，该项目还将在几个对国家利益具有重要意义的领域产生广泛影响。它将有助于更有效地利用能源，最大限度地减少与化石燃料枯竭相关的长期环境问题，有助于使以氢气为能源载体的可持续能源经济更加可行，并通过为我们的军队提供更多轻型便携式电力的选择，帮助使我们的国家更加安全。

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.