CARBON NANOTUBE MATERIALS FOR HYDROGEN STORAGE

Abstract

Carbon single-wall nanotubes (SWNTs) are essentially elongated pores of molecular dimensions and are capable of adsorbing hydrogen at relatively high temperatures and low pressures. This behavior is unique to these materials and indicates that SWNTs are the ideal building block for constructing safe, efficient, and high energy density adsorbents for hydrogen storage applications. In past work we developed methods for preparing and opening SWNTs, discovered the unique adsorption properties of these new materials, confirmed that hydrogen is stabilized by physical rather than chemical interactions, measured the strength of interaction to be ~ 5 times higher than for adsorption on planar graphite, and performed infrared absorption spectroscopy to determine the chemical nature of the surface terminations before, during, and after oxidation. We also made significant advances in the synthesis of SWNT materials by turning to a laser-vaporization method rather than the arc-generation method employed previously. In addition, we began to develop methods to purify nanotubes and cut nanotubes into shorter segments. This year we have made further advances in the development of our laser synthesis technique, and we now generate crude material containing 20-30 wt % SWNTs at a rate of ~150 mg / hr or ~ 1.5 g / day. In addition we