Nanogenerator could power cellphone through the beat of a heart

Posted by Emma Woollacott

Scientists have created what they say is the first practical nanogenerator, capable of powering a phone or iPod with the beats of the user's own heart.

The team has been working on the device for six years, but has recently managed to improve its power output by 1,000 times and its voltage by 150 times to make it a viable proposition. They've now demonstrated using the device to power an LED light and LCD, using a regular pinch of the fingers to supply power.

"This development represents a milestone toward producing portable electronics that can be powered by body movements without the use of batteries or electrical outlets," says lead scientist Zhong Lin Wang of the Georgia Institute of Technology.

"Our nanogenerators are poised to change lives in the future. Their potential is only limited by one’s imagination. If we can sustain the rate of improvement, the nanogenerator may find a broad range of other applications that require more power."

Personal electronics devices could be powered by footsteps activating nanogenerators inside the sole of a shoe, for example, or implanted insulin pumps powered by a heart beat.

The device is based on zinc oxide (ZnO) nanowires, which can generate an electric current when strained or flexed. That movement can be virtually any body movement, such as walking, a heartbeat, or blood flowing through the body.

Wang’s group found a way to capture and combine the electrical charges from millions of the nanoscale zinc oxide wires. They also developed an efficient way to deposit the nanowires onto flexible polymer chips, each about a quarter the size of a postage stamp. Five nanogenerators stacked together produce about  the same voltage as two regular AA batteries.

"While a few volts may not seem like much, it has grown by leaps and bounds over previous versions of the nanogenerator,” says Wang. “Additional nanowires and more nanogenerators, stacked together, could produce enough energy for powering larger electronics, such as an iPod or charging a cell phone."

Wang said the next step is to further improve the output power of the nanogenerator and find a company to produce it commercially. It could hit the market in three to five years, he says.

The research was presented at a meeting of the American Chemical Society.