If you’re not familiar with piezoelectrics, it’s a good time to get current. (Here all week, folks.) Researchers at RMIT University and Australian National University have finally quantified the voltage output of piezoelectric nanofilms — thin film materials capable of converting pressure into electrical energy.
The voltage output of up to 40 mV and current transients up to 200 pA, compare very well to published results for nanowire generators of 30 mV and 100 pA which were shown to be suitable for powering nanosensors. [ 24 ] The effective power generated is 250 W mm^- 2 at 5.0 mN force.
Applications for this kind of pressure-turned-power are limited only by the scale-up logistics of mass producing the films. Imagine a laptop powered by typing or clicks. Or shoes that charge your iPod while you work out. As long as a force is acting upon the film, energy is being produced–so, theoretically, until the film is damaged in a way that renders it incapable of transferring energy, the output is potentially unlimited.
There are no hard and fast projections for when (or if) the new batteries will reach market, but when they do, it’s safe to say they’ll be around for a while.