ABSTRACT: The mission will be to provide bridging science for the publishable, fundamental research and development of next-generation polymer electrolyte membranes (PEM), membrane electrode assemblies (MEA), and related fuel cell materials systems. In particular, we will dramatically extend understanding of the influence of several critical factors on transport properties. This new knowledge will be used to optimize and develop new materials for use in fuel cells. Critical issues pertaining to the function and stability of the MEAs will also be addressed. The focus is on the requirements for fuel cell systems, but could extend to a related variety of devices.
PEM fuel cell systems are an environmentally attractive energy or power source for a diverse array of applications, including cars, residences, and portable electronics, [1-3] and must function with critical performance and economy. A perfluorinated sulfonic acid copolymer (PFSA) (Nafion®) membrane is now used as the membrane, which is often supported on a fluorinated polymer fabric. This research will investigate the formation and durability of new MEAs based on commercially available fluoropolymer coated glass fabrics, which are more rigid, temperature resistant, and cost effective. The MEA consists of composite electrodes bonded to the membrane, which must have adequate electronic and protonic conductivity, gas permeability, and mechanical stability for thousands of hours under operating conditions. The key problems include maintaining adequate protonic conductivity and gas permeability within the catalyst layer under a range of hydration conditions, and maintaining a suitable structure between membrane and electrode phases. Research is ongoing to develop systems other than direct H2 that can operate using reformed hydrocarbon fuels, e.g., gasoline and methanol. Each has significant technical hurdles that presently entail either low efficiency or high cost. Potential solutions could arise from university led bridging research that integrates industrial and national laboratory efforts. It is now vital to integrate cross-cutting research in polymeric materials design and synthesis by combining the knowledge of highly qualified academic scientists and engineers at Virginia Tech (VT), Virginia Commonwealth University (VCU), and Iowa State University (ISU) with expertise from national lab, specifically Los Alamos National Laboratories, and industrial sectors. It is clear that progress in this field can be significantly accelerated through the proposed enabling science. Toward that end, we propose to synthesize new PEM materials with guidance from sophisticated models of proton and water transport, and will subject these materials to thorough molecular and structural characterization to fully understand how molecular engineering affects PEM performance. Emphasis will be placed on how polymer microstructure can be tailored to maximize ionic conductivity and mechanical properties when hydrated, maximize proton conductivity at high temperatures (e.g., 120°C), and minimize methanol crossover. Our team has access to an array of sophisticated techniques to carry out this mission that are described herein, and we have strong links to industries and national labs focusing on PEM technology to provide realistic measures of fuel cell performance.
Success in these fundamental efforts will lead to a number of developments with long-term benefits. These include: the development of fuel cell systems based on mechanistically understood, technologically advanced and durable proton exchange membranes will contribute to energy independence and the environment through replacement of the internal combustion engine for many energy sources, stationary (residential) power and consumer electronics, including power sources, laptop computers and cell phones.
For more information on
contact Dr. McGrath or Laurie Good