Carbon nanotube materials from hydrogen storage
- National Renewable Energy Laboratory, Golden, CO (United States)
The lack of convenient and cost-effective hydrogen storage is a major impediment to wide scale use of hydrogen in the United States energy economy. Improvements in the energy densities of hydrogen storage systems, reductions in cost, and increased compatibility with available and forecasted systems are required before viable hydrogen energy use pathways can be established. Carbon-based hydrogen adsorption materials hold particular promise for meeting and exceeding the U.S. Department of Energy hydrogen storage energy density targets for transportation if concurrent increases in hydrogen storage capacity and carbon density can be achieved. These two goals are normally in conflict for conventional porous materials, but may be reconciled by the design and synthesis of new adsorbent materials with tailored pore size distributions and minimal macroporosity. Carbon nanotubes offer the possibility to explore new designs for adsorbents because they can be fabricated with small size distributions, and naturally tend to self-assemble by van der Waals forces. This year we report heats of adsorption for hydrogen on nanotube materials that are 2 and 3 times greater than for hydrogen on activated carbon. The hydrogen which is most strongly bound to these materials remains on the carbon surface to temperatures greater than 285 K. These results suggest that nanocapillary forces are active in stabilizing hydrogen on the surfaces of carbon nanotubes, and that optimization of the adsorbent will lead to effective storage at higher temperatures. In this paper we will also report on our activities which are targeted at understanding and optimizing the nucleation and growth of single wall nanotubes. These experiments were made possible by the development of a unique feedback control circuit which stabilized the plasma-arc during a synthesis run.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- OSTI ID:
- 183294
- Report Number(s):
- NREL/CP-430-20036-Vol.2; CONF-9504160-VOL.2; ON: DE95009296; TRN: 95:008711-0005
- Resource Relation:
- Conference: 1995 DOE/NREL hydrogen program review, Coral Gables, FL (United States), 18-21 Apr 1995; Other Information: PBD: Sep 1995; Related Information: Is Part Of Proceedings of the 1995 US DOE hydrogen program review, Volume II; PB: 876 p.
- Country of Publication:
- United States
- Language:
- English
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