Cao

1. Coherent Carbon Cryogel – Hydride Nanocomposites for Efficient Hydrogen StorageGuozhong Cao, University of Washington, Seattle, DMR 0605159 While fuel cell technology has rapidly advanced towards application in automobiles, the on-board storage of the hydrogen needed to power a fuel cell has not. Pressurized hydrogen storage tanks would require impractically bulky and heavy vessels and liquid hydrogen must be stored at – 251 C making it logistically very difficult. Schematics of the microstructures of : carbon cryogel (left) and coherent carbon cryogel - hydride nanocomposite (right) Solid state hydrogen storage offers a solution because it requires essentially no pressure, is inert at typical operating temperatures, and releases hydrogen on demand. This research will utilize advancements in nanotechnology to improve the performance of solid state hydrogen storage materials – a much needed step towards development of the new American energy economy. The success of the project will be a significant step toward the realization of a hydrogen economy and will attain a better fundamental understanding of the physical properties and chemical behavior when matter shrinks to the nanometer scale. This research will expose, educate, and attract graduate and undergraduate students to the field of energy related materials and technology and be environmentally conscious through their thesis research, faculty seminars, workshops, and publications.

2. Coherent Carbon Cryogel – Hydride Nanocomposites for Efficient Hydrogen Storage Guozhong Cao, University of Washington, Seattle, DMR 0605159 This research is to develop novel nanocomposites consisting of a highly porous chemically modified carbon cryogel filled and intimately mixed with hydrides and optionally coated with a porous catalyst oxide layer. The extremely high surface area (>2000 m2/g) and porosity (>95%) of carbon cryogels facilitates an intimate contact between hydrides and the carbon network with possible catalytic effects as well promoting a homogeneous dispersion while trapping hydrides inside the tunable pores ranging from <1 nm to 100 nm in diameter. Such coherently structured nanocomposites have demonstrated to have a tunable dehydrogenation temperature that decreases with reduced pore size (shown on right), doubled capacity of dehydrogenation, and total suppression of hazard byproduct. This research has already supported four graduate students (two women and one Hispanic) with one graduated in January 2007 and three are continuing their dissertation research. This grant has also supported 3 undergraduate research, and resulted one journal paper published, two submitted and three more in preparation, and various seminars and invited talks including one in the 2007 Fall MRS meeting. Dehydrogenation temperature of hydrides reduces as a function of pore size of carbon cryogels, from 105 C in bulk powder to 97 C in ~ 8 nm pores and further to 94 C in ~ 4 nm pores. • A.M. Feaver, S. Sepehri, P. Shamberger, T. Autrey, and G.Z. Cao, “Coherent Carbon Cryogel – Hydride Nanocomposites for Hydrogen Storage,” Journal of Physical Chemistry B111, 7469-7472 (2007). • S. Sepehri, A. Feaver, A. Stowe, T. Autrey, and G.Z. Cao, “Spectroscopic Studies on Dehydrogenation of Ammonia Borane- Carbon Cryogel Nanocomposites,” Journal of Physical Chemistry, submitted. • B.B. Garcia, A.M. Feaver, G.T. Seidler, and G.Z. Cao, “Effect of Pore Morphology on Electrochemical Properties of Carbon Cryogel Supercapacitors,” Journal of Applied Physics, submitted.