If you take a carbon nanotube and set fire to one end, that tube will generate electricity. And if you're an MIT genius, you can heat those tubes with regular old table sugar, pack them together, and have a battery that produces almost the same output as the one in your notebook computer, phone, or tablet. For comparison, the MIT sugar battery is already as efficient as the 25-year-old technology that powers today's devices.
The MIT team, led by professor Michael Strano, took what it describes as "lab curiosity" and worked it up into a useful, everyday technology. The Thermopower Wave (TPW) device runs on regular table sugar, burning it as a fuel to heat the nanotube banks. This heat pushes a kind of wave of electrons down the tubes, which results in a current. Sugar is the choice right now, but any heat source could be swapped in if found to be more efficient. It's little like Doc Brown's Mr. Fusion device from Back to the Future, only without all the troublesome nuclear reactions.
The device, detailed in a new paper published in Energy & Environmental Science, isn't quite ready to be dropped into your iPhone, but it is remarkable for its efficiency. While it is only 1% efficient in converting heat energy to electrical energy, that's 10,000 times better than the results achieved when the phenomenon was first discovered, and not far from the best of today's battery tech. If nothing else, this shows how crappy our battery technology really is.
Right now, the device can power an LED light. It also has some unique features that make it better than existing batteries for some applications. For instance, because it burns fuel to work, it can store that fuel indefinitely, instead of slowly self-depleting like a stored battery. MIT gives the example of deep-space probes, but it would be just as handy to keep boxes of these things in the basement for emergencies. The technology is also scalable down to sizes impossible for current batteries, with implications for powering tiny wearable devices. And finally, these batteries can deliver huge bursts of power if needed.
Not bad for a power source that runs 100% off a renewable resource.