In a small step toward making electronics that can power themselves, researchers at Georgia Tech and the University of Dayton in Ohio have discovered how to generate electricity just by bending tiny wires back and forth.

By embedding the wires in a thin film covering, they could be sewn into the sole of a shoe or woven into clothing, generating juice with each step and every movement.

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Georgia Tech

Professor Zhong Lin Wang’s nanogenerators generate electricity via the stretching and relaxing of tiny zinc oxide wires.

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“You could even put (them) in a flag of the United States and whenever the wind blows, it would generate electricity,” said Zhong Lin Wang, the Georgia Tech professor and chief researcher behind the device he calls a “flexible charge pump.”

Joining Wang and other Georgia Tech researchers on the project was Liming Dai of the University of Dayton’s department of chemical and materials engineering.

The researchers’ new nanogenerator produces a mere 45 millivolts of power. By comparison, a standard AA battery delivers about 33 times that, Wang said.

But by stacking layers of the little zinc oxide wires on top of each other, future models could someday generate enough energy to power an iPod, medical devices such as automated drug delivery systems, or military equipment like sensors or radios.

Wang and his fellow researchers have been working on nanogenerators for years. In 2007, they unveiled a prototype device that generated electricity when tiny wires were rubbed together.

The new device, Wang said, is a major improvement because the wires produce electricity when they’re bent, not when they’re rubbed together. That means less friction, less wear and a lot more durability, he said.

Also, embedding the wires in film protects from water, sweat and other liquids that can render them inoperable.

“For practical applications, this is a giant step forward,” Wang said.

Still, plenty of steps are left before their device can be marketed as a viable replacement for batteries. Next up for researchers is figuring out how best to make multiple wires work together. Then they have to figure out how to make multiple sheets of wires provide more voltage.

“I would say, give us three years,” Wang said.