Original URL: http://www.theregister.co.uk/2010/03/08/ring_o_fire_batteries/

MIT profs produce 'Ring of Fire' nanotube superbatteries

Electron-furtling boffins claim 100x li-ion energy

By Lewis Page

Posted in Science, 8th March 2010 10:58 GMT

MIT boffins say they have discovered a radical new source of portable energy, powered by a burning ring of fire, which can hold a hundred times as much juice as a li-ion battery.

The key, of course, is nanotubes. As you do, the boffins at MIT decided to coat some of these amazing cylindrical carbon molecules with "a layer of reactive fuel" which was then ignited at one end.

According to a statement issued by MIT, the resulting "ring of heat speeds along the tube 10,000 times faster than the normal spread of this chemical reaction". The heat pulse screaming down the nanotube also makes electrons move along it - far more than the MIT researchers had expected.

"Lo and behold, we were really surprised by the size of the resulting voltage peak," says Michael Strano, chemical engineering prof.

It seems that the extra power over and above what thermo-electric calculations had predicted arises from electrons or "electron holes" being picked up and pushed along by the ring-o-fire thermal wave in the same fashion as a surfer carried by an ocean roller.

“We call it electron entrainment, since part of the current appears to scale with wave velocity," says Strano.

The researchers say that their new firepowered battery tech holds a hundred times as much energy, weight for weight, as the same weight of lithium ion batteries.

However they don't seem certain that it will scale up into the realm of gadgetry, let alone cars or VTOL pod-copters etc. Rather, Strano and his colleagues prefer to talk of grain-of-rice sized miniature medical implants, or dust-mote sized airborne sensor networks.

There's also some mildly worrying talk of "a great deal of power being given off as heat and light", hinting at a possible worsening of that well-known modern scourge the gadget-related trouser inferno in any future where MIT Ring-O-Fire™ batteries became widespread.

There's no doubt a lot of work to be done before then.

Strano and the team's research, lead-authored by PhD student Wonjoon Choi, is published in Nature Materials. ®