In their current form, the carbon nanotube wires are one percent efficient in converting heat to electricity. While that doesn't sound like much, that's still 10,000 times more efficient than what team lead Michael Strano originally reported when he discovered that carbon nanotubes can be used as a power source. Other combustible materials besides sugar could improve their efficiency even further.

The team already proved that the wires can power simple devices like LED lights, but it'll take time before the technology is ready to compete with lithium-based batteries. This power source could be scaled down for tiny wearables that are already hitting the market. But the researchers believe it could also be scaled up for use with deep-space probes. It can remain dormant for many years as the probe journeys through space and provide the power it needs whenever heat is applied.