The objective of this research is to explore the use of surface-initiated atom transfer radical polymerization (SI-ATRP) and electrospinning technologies to create a novel type of hybrid fuel cell membrane. Fuel cells are promising candidates for ?clean? power generation because they provide electricity without combustion and pollutants associated with burning fossil fuels. Current PEMFC technologies use Nafion® membranes to separate the fuel from the oxidant and transport protons from the anode to the cathode. However, Nafion® suffers from problems including low operating temperature, limited sulfonic acid content, poor proton conductivity at low relative humidity, insufficient mechanical stability, and high cost. The work proposes to synthesize a novel type of organic-inorganic hybrid membrane by using SI-ATRP technology to generate extra-high density, ultra-long functional polymers directly in the nonwoven pores of electrospun SZrO2 nanofiber-based porous frameworks. These hybrid membranes will also be integrated with novel catalyst layers to achieve high fuel cell performance.
Intellectual merit: SI-ATRP is a recently developed technology of ?living? or ?controlled? radical polymerization that can realize well-defined, high-density polymer chains with exceptionally large molecular weights and low polydispersities on solid surfaces. Electrospun S-ZrO2 nanofibers have high conductivities even at high temperatures (> 150oC) and low humidities, and can form a porous nonwoven framework to provide excellent mechanical support for attaching polymers with unprecedented sulfonic-acid content while still maintaining good dimensional stability. In addition to the high conductivity of the S-ZrO2 frameworks, the extra-high content of closely-associated acid groups achieved by this method can provide a large amount of ?free? protons to further enhance the membrane performance. The resultant hybrid membranes have advantages of high proton conductivity, increased operating temperature limit, good mechanical strength, long operational life, and low cost, and hence they can significantly improve the performance of fuel cell systems.
Broader impacts: The results of this proposed research are expected to have important scientific and economic impacts. Foundation for fabricating nanofiber-based porous inorganic and organic-inorganic hybrid membranes with well-defined structures and multi-functionalities will be established. Research of fuel cell technologies, which will reduce our foreign oil dependence, improve air quality, and reduce greenhouse gas emissions, will also be advanced. These research and education activities in novel energy-related materials and systems will help the U.S. stay in a lead position in these strategic fields.
