To enable the hydrogen economy of the future, we need to find ways to economically produce hydrogen as well as store it and use it. Take hydrogen-powered vehicles, for example. The environmental community touts the benefits of hydrogen-powered cars and there are certainly benefits to be gained from such vehicles. But before we can see scads of hydrogen-fuelled vehicles on the road, we have to solve some basic problems. One of the sticking points is onboard hydrogen storage. How can we store large enough quantities of hydrogen safely and at the same time avoid adding extra weight to vehicles? The answer, according to Emeryville, CA-based Nanomix Inc. is cryogenic storage of hydrogen using nanostructures.

Nanomix has received two US patents--US 6,672,077 and US 6,748,748 - related to the company's hydrogen storage research. The first patent relates to storing hydrogen in nanostructures using physisorption. The second relates to a hydrogen storage and supply system.

We have been tackling hydrogen storage for many years. Some techniques call for storing hydrogen in tanks under high pressure. Others call for liquefying hydrogen at temperatures below 20 K using a helium-based cooling system. Should a vehicle be involved in an accident, there is a rather high risk that there will be a fast and uncontrolled release of hydrogen, which could be followed by an explosion or fire. Further, if we expect hydrogen-powered cars to have the same range of current vehicles, we need to be able to store at least 10 kg of the fuel, say Nanomix officials.

For the liquefaction or high pressure methods, containers big enough to hold that much fuel likely will be too heavy to use onboard. Finally, neither the liquefaction nor high pressure methods are very energy efficient. So we are back to the typical hydrogen conundrum - how can you make and use hydrogen without expending more energy than you receive? That is where nanotechnology can help.

In the Nanomix technology, nanostructures based on sp.sup.2 bonded triangular lattices - such as nanococoons, nanohorns, nanotubes and the like - are used to form planar networks. These nanostructures are able to adsorb large quantities of hydrogen and therefore boost the weight per cent storage efficiency. Rather than using chemisorptive bonds, the Nanomix technology calls for physisorption of hydrogen by the nanostructures.

The technology uses cryogenic principles, which allows the hydrogen to be stored in the nanostructures at temperatures greater than the liquefaction temperature of nitrogen, 77 K. This cryogenic approach makes hydrogen storage more cost effective, according to the company.

The hydrogen storage system uses a container that has at least two walls and has cold enclosure with an ideal temperature range of 150 K to 220 K. The cold enclosure would have porous nanostructure material that could occlude hydrogen. The container would have at least one port, providing an outlet for hydrogen flow from the cold enclosure.

Hydrogen could be recovered from the storage system by either heating it with a current-driven resistor or by using leakage heat to drive the desorption of hydrogen. Many significant players in the automotive industry are interested in the technology, David Haberman, Nanomix's designated hydrogen energy consultant, tells Nanotech Alert. In fact, the company has "heard from OEMs [original equipment manufacturers] around the world."

However, some critics, such as the compressed gas industry, claim the technology will be too expensive. But, Haberman points out that the Nanomix technology actually will open up markets to small and large users of hydrogen.

Nanomix's strategy is to continue to develop the technology, but to leave implementation of the technology to a partner, who can work at the infrastructure level. Therefore, Nanomix is actively looking for an industrial partner to help continue the development of the nanostructured hydrogen storage system.

Details:

David Macdonald, President and CEO

Nanomix Inc., 5980 Horton St., Suite 600

Emeryville CA 94608

Phone: 510-428-5300

Fax: 510-658-0425

E-Mail: info@nano.com

To comment on this article, write to us at tiresearch@frost.com

To find out more about Technical Insights and our Alerts, subscriptions and research services, access http://ti.frost.com