What if you could be your own power plant? What if walking up the stairs could power your Apple Watch, or doing 10 sets of burpees could fire up a heart-rate monitor?
A group of scientists at MIT think they might have found a solution to humankind's biggest energy puzzle: how to unleash the power-generating potential of our bodies. Using thin layers of lithium alloys as electrodes, they are working on a device that is powered by human movement.
"It's a very thin patch you can't really feel, but when you bend it it generates electrical energy from that motion," one of the lead researchers, Soon Ju Choi, 32, told MTV News of the device he said is around 300 nanometers thick (about the size of a particle that could fit through an air filter). "The idea came when we observed that when there is stress in a battery electrode it can generate chemical potential from the outside stress."
That stress is usually a bad thing for a lithium ion battery (think of those rechargeable batteries in your iPhone or laptop). But when Choi's team built a flexible version they found that the stress not only didn't interrupt the ability to create energy, it actually helped manufacture it.
What's exciting about the team's experiment is that it could some day provide a basically unlimited supply of clean, renewable energy fueled by walking, bending your joints or any other repeated motion. Earlier experiments seeking this kind of solution have relied on friction (triboelectric) or producing a small amount of voltage by bending crystals (piezoelectric), but Choi said those methods required high-frequency, large sources of motion to produce energy. The MIT group's method relies on repeated bending of a sliver-like sandwich of metal and polymer sheets (picture above) that are more flexible and could be wearable.
"It's transforming mechanical bending into electrical energy," he said. "If you connect it to a wireless system we could power a wireless device attached to the body at a joint, like an Apple Watch or a heart beat monitor." Unlike a traditional rechargeable battery -- which takes in electricity, stores it and then releases it -- this new system takes in mechanical energy and then puts out electricity by squeezing the lithium ions through the polymer, which outputs an alternating current (AC) that is instantly ready to power up a device.
At this point, the MIT team (which also includes research advisor Prof. Ju Li) has achieved 15 percent efficiency compared to the theoretically predicted capacity ("a comparison between the measured electricity compared to the theoretically predicted/expected amount of electricity per bending").
But Choi's research partner, Sangtae Kim said it could potentially get up to 100 percent efficiency with "a few engineering breakthroughs," which is, well, super exciting. "[15 percent] was more than we expected,' Choi said of the devices that have held up through 1,500 cycles of tests. "This is a totally new way of energy harvesting and we could easily commercialize this material and have some sort of device soon."