Schematic of a piezoelectric generator by researchers at Georgia Tech

Technology Review reports today on work at Georgia Tech that has finally let to an energy scavenging generator powerful enough to power an LED display. At 1.5 by 2 centimeters, it’s also small enough to power devices embedded in the human body.

On a recent trip to Medtronic, a the world’s premier maker of pacemakers and other medical devices, I learned of engineers’ quest to build ever-smaller implants. The ultimate goal is injectable devices that can remain the body indefinitely. But power is a major limiter, since batteries, even rechargeables, have to be changed eventually.

Energy scavenging devices could remove that limitation by allowing implants to draw power from the movements of the human body, or from temperature differences between the body and the surrounding environment. I wrote about some of the challenges in Smithsonian’s 40th anniversary issue last summer.

The Georgia Tech research, led by Zhong Lin Wang, could represent an enabling breakthrough. Wang and his team’s generator consists of a composite containing piezoelectric zinc oxide nanowires sandwiched between electrodes. It produces about 2 volts when compressed about 4 percent every second.

Read Wang’s Nano Letters paper on his work.