If you thought lithium-ion batteries catching fire were dangerous, how about a portable power source that actually relies on igniting its fuel from the get-go? That's pretty much what a new battery alternative developed at MIT does. A few years ago, researchers found that they could coat a long thin carbon nanotube — like a sheet of graphene wrapped into a tight cylinder — in combustible material. Letting it burn from one end, like a long wick or fuse, they discovered that the the system generated a tiny electrical current. The heat pulse pushes electrons along the tube, creating a current.
Since, researchers at MIT have been trying to refine the rather clumsy process. While the approach remains broadly similar, the team — led by MIT's Michael Strano — has now improved the efficiency of the system by a factor of 10,000. The secret lies in the coating: The nanotubes are now coated in sucrose, while the first versions used explosive materials.
The result is a power source that, kilo-for-kilo, provides a similar power output to modern batteries. But the researchers claim that, unlike most batteries, the system could sit indefinitely without losing power. There's also scope for the technique to produce (hopefully carefully controlled) short bursts of power that are far higher than batteries can manage. The research is published in Energy & Environmental Science.
It is, however, still very much in its early stages, and the cells created so far are only large enough to power some modest LED lights. So it might be a little while yet before ignition in your battery is a good thing.
Top image: Time lapse shows a sucrose-coated carbon nanotube burning, from left to right.