Prepare for a new 'wave' of energy

Want someday to wave good-bye to replacing batteries or recharging your iPod or BlackBerry?

Some Georgia scientists are working on it, with the wave itself actually providing the device with the juice it needs.

Don't feel like waving? Just go for a walk. Stretch your arms. Wiggle your finger. Enjoy a breeze. Let your heart beat. All are possible sources of energy using technology that turns movement of any type into electricity — a technology especially useful for microscopic devices that currently need batteries.

"In the last decade, scientists have developed a lot of nanodevices, but there's not much effort in how … you solve the power need for those little devices," lead researcher Zhong Lin Wang, a professor at the School of Material Science and Engineering at the Georgia Institute of Technology, said Thursday while discussing the research at the American Chemical Society's 237th national meeting at the Salt Palace.

"Because it's sized small, it requires small power to operate, so therefore (it can) make it possible you can harvest energy from the environment to power these little devices."

The researchers have been able to grow zinc-oxide nanowires on a variety of materials. Any movement of those nanowires turns them into nanogenerators, able to conduct electricity harvested from the environment's low-frequency vibrations. The key property of the wires is that they can generate an electric current when subjected to any mechanical stress, meaning any movement.

And not a lot of movement, because the nanowires are so small. The diameter of each wire is one-five-thousandths the diameter of a human hair. Placed end to end, 25 would fit in the diameter of a hair.

Wang admits that the output voltage and power need to be improved, but, if working simultaneously and continuously as researchers expect, the nanogenerators someday could make a variety of devices battery-free, making them ideal for independent, wireless and remote operations.

IPod fun aside, the technology could have lifesaving applications. Imagine troops in the field, far from a power source but able to use their communication devices without lugging heavy batteries along. Imagine sensors used to detect terrorist biohazard materials but sprinkled far across hostile territory, where replacing batteries would be dangerous, if not impossible. And the nanosystems would be able to work well in areas that are dusty, rainy or dark, topping the capabilities of solar cells.

The technology also could have lifesaving uses in the medical field. Biomedical sensors implanted under the skin no longer would need batteries, for example.

The nanowires can work in liquids or in the air. And because they can be grown on various surfaces — metals, ceramics, polymers and cloth — scientists someday might use them to develop a "power shirt" that produces electricity when the wearer stays active, or a "power tent" that generates the juice while rustling in the wind.

"Quite simply," Wang said, "this technology can be used to generate energy under any circumstances, as long as there is movement."

The research has been funded by the Defense Advanced Research Projects Agency, the U.S. Department of Energy, the National Institutes of Health and the National Science Foundation.

E-mail: bwallace@desnews.com