Isis innovation investigates sand-powered fuel cells

A new method that combines silicon and water to produce hydrogen could serve as a source of emergency gas for future fuel cell vehicles.

The technique developed by an Oxford University research team led by chemist John Foord generates hydrogen locally at low temperatures.

Project manager Dr Jamie Ferguson, who is helping commercialise Foord’s work through the university’s spin-out company Isis Innovation, explained combining silicon and water to produce hydrogen has been considered by others before but technical hurdles stood in their way.

Under normal conditions, silicon does not largely react to water. While it initially rapidly reacts, Ferguson said, it stops abruptly as soon as an oxide layer is formed.

Foord and his team were able to overcome this, he said, by developing a new method for grinding silica, otherwise known as sand, into silicon nanopowder. When in this nano-state, it is claimed silicon will readily generate hydrogen when contacted with water at temperatures between 70 and 90 degrees Celsius.

Ferguson said one of the main advantages is the only byproduct is sand, which can be safely disposed or recycled.

In addition to developing a new method for milling sand into silicon nanopowder, Foord’s team also developed a material that encapsulates the silicon nanopowder particles. Ferguson said this was done to shield the particles from the air because the silicon nanopowder is so reactive it could theoretically generate hydrogen with exposure to even minimal amounts of water.

While initially being targeted for emergency supplies of hydrogen or lower power fuel cell applications such as laptops or communication devices, the technology has potential to be scaled up.

Foord and his team view local generation of hydrogen as a more plausible alternative to other methods proposed for fuelling portable hydrogen fuel cells.

While hydrogen is energy rich compared to petroleum on a per-weight basis, it is relatively poor on a volumetric basis. This means in portable fuel cell applications, significant volumes of hydrogen will need to be carried on-board unless high pressure or cryogenic hydrogen storage is used. These methods, however, both have significant energy penalties.

Ferguson said the new Oxford method could be considered as a different way of looking at hydrogen storage, ‘except the hydrogen storage here is the water,’ he added.

Ferguson said the team is now currently open to offers from company to license its technology.