Charge your cell phone by walking

Forgot to charge your cell phone last night? Imagine that you could power it by walking. Weirder still, you might be able to just spray a new battery on.

Z.L. Wang shows an enlarged image of zinc oxide nanowires, less than the width of a hair in reality.

These concepts are being developed by two leading nanotechnology researchers who are developing cleaner, more efficient ways of delivering electrical power. In working toward making these ideas realities, they are making use of structures that are 100 nanometers or smaller, where one nanometer is a billionth of a meter.

"[The nanoscale] can make the components small, sensitive and high-performance," said Zhong Lin "Z.L." Wang, distinguished professor at the Georgia Institute of Technology's College of Engineering. "The toughness and the flexibility increase by orders of magnitude."

Barely lifting a finger

Wang and colleagues are working on harnessing the energy of the body's natural movements to power small devices. Even the simple act of moving your fingers while typing creates energy that could power a small device, and these researchers are showing that nanotechnology can enable this transformation.

Here's the hard science: To take advantage of animal movement for energy, Wang's team makes use of the piezoelectric effect, which refers to the ability of certain materials to generate an electric potential when a stress is applied to them. For instance, if you compress a crystal, it temporarily changes shape, causing the ions inside the crystal to polarize and produce a voltage drop.

ENERGY YOUR BODY PRODUCES

MECHANICAL ENERGY
Blood flow: 0.93 watts
Exhaling: 1.00 watts
Inhaling: 0.83 watts
Walking: 67.0 watts

ELECTRICAL ENERGY AVAILABLE
Blood flow: 0.16 watts
Exhaling: 0.17 watts
Inhaling: 0.14 watts
Walking: 11.4 watts

full story here: click