March 17, 2014
Harnessing Everyday Motion To Power Our Mobile Devices
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Lee Rannals for redOrbit.com - Your Universe OnlineResearchers at the 247th National Meeting & Exposition of the American Chemical Society (ACS) presented the possibilities of harnessing motion to power mobile devices.
The team is setting out to transform the way scientists look at mechanical energy. Conventional energy sources rely on old science that requires power plants and a grid to distribute electricity.
"Today, coal, natural gas and nuclear power plants all use turbine-engine driven, electromagnetic-induction generators," Zhong Lin Wang, from the Georgia Institute of Technology, said in a statement. "For a hundred years, this has been the only way to convert mechanical energy into electricity."
The team worked on a miniature generator based on an energy phenomenon known as the piezoelectric effect. They found that this method produced more power than expected, and decided to look into what caused the spike.
According to the researchers, two polymer surfaces in the devices rubbing together helped produce what is known as the triboelectric effect, which is essentially static electricity. Using this discovery the team developed the first triboelectric nanogenerator (TENG) by pairing two sheets of different materials together. These sheets essentially toss electrons from one to the other when touched, but when they are separated a voltage develops between them.
The team originally wrote about TENG in 2012, but since then have boosted the power output density by a factor of 100,000, with the power density reaching 300 Watts per square meter.
Wang said that just with the stomp of his foot, he is able to use TENG to power up a thousand LED bulbs on a sheet. The researchers have incorporated TENG into shoe insoles, whistles, foot pedals, floor mats, backpacks and ocean buoys for a variety of applications.
The team believes that TENG will be able to be used to harness the power of everyday motion, including everything from stepping to ocean waves. These movements help produce mechanical energy that has been around all along, but scientists didn’t know how to convert it directly to usable power in a sustainable way.
"The amount of charge transferred depends on surface properties," Wang said in a statement. "Making patterns of nanomaterials on the polymer films' surfaces increases the contact area between the sheets and can make a 1,000-fold difference in the power generated."