In the Future, You Might Charge Your Cell Phone by Stroking It

New green-power technology transforms motions like walking and touching into potent jolts of energy.

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Years down the road, cities could be rife with people gently stroking and blowing on their cell phones. This wouldn't be the creepy A.I.-love premise of Her come true, but a new form of green energy that transforms repetitive movement into a battery charge.

That's the vision of Zhong Lin Wang, anyway, who researches nanotechnology at the Georgia Institute of Technology. Wang recently spoke of his hopes for motion-based power at the American Chemical Society's annual meeting in Dallas, praising the endless potential of something called the "triboelectric nanogenerator" or TENG. The technology underlying it, he asserts, could "change the world we live [in] in the near future."

Basically, his lab has designed a sheet of material loaded with grids of really tiny structures, like these:

When these sheets are arranged on top of each other, pressing them together or sliding them back and forth generates an electric charge. (It's the same piezoelectric concept underlying this self-powered office desk.) That means you could hypothetically design a cell-phone screen that sends hits of power to the battery anytime it's touched, or shoes that generate juice when walked upon, or a jacket that whips up electron storms when buffeted by gusts of wind.

The first generations of the TENG were fairly dinky, producing only a few volts per hour. But Georgia Tech has perfected the technology to such a degree that one foot stomp can now light up a screen of 1,000 LEDs. Wang believes these pressure-based generators could help "power the world" in a mere 5 years, becoming a source of sustainable energy that's separate from more traditional power plants and electrical grids. That sounds optimistic, but it's intriguing to contemplate, as the TENG team explains:

His group has incorporated TENG into shoe insoles, whistles, foot pedals, floor mats, backpacks and ocean buoys for a variety of potential applications. These gadgets harness the power of everyday motion from the minute (think vibrations, rubbing, stepping) to the global and endless (waves). These movements produce mechanical energy that has been around us all along, but scientists didn't know how to convert it directly to usable power in a sustainable way until now....

With those improvements, Wang said his group is now working on commercializing products to recharge cell phones and other mobile devices using TENG. Down the road, he envisions these nanogenerators can make a far bigger impact on a much larger scale. Researchers could use the technology to tap into the endless energy of ocean waves, rain drops and the wind all around us – with tiny generators rather than towering turbines – to help feed the world's ever-growing energy demand, he said.

Have a look at the minuscule power source at work:

Top image: Kostenko MaximShutterstock.com

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