Flexible nanogenerator harvests muscle movement to power mobile devices

The consumer world is becoming powered by mobile devices, but those devices are still powered by being tethered to a wall or a reserve power pack. What if you could generate power for your mobile devices simply by moving your body, and the power source was almost unnoticeable? A new device developed at the National University of Singapore aims to fulfill both of those requirements.
The flexible nanogenerator resembles a small, stamp-sized patch that attaches to your skin. It uses your skin as a source of static electricity, and converts it to electrical energy — reportedly enough to power a small electronic device, like a wearable. The device, presented at the MEMS 2015 conference last week, can generate 90 volts of open-circuit voltage when tapped by a finger. The researchers presented the patch as a self-powered device that can track the wearer’s motion. Electricity The power generates thanks to the triboelectric effect, which is when certain types of materials can become electrically charged through contact and friction with another material — in this case, the patch gains the charge through fiction with human skin. When the two materials are pulled apart, they generate a current that can be harvested. An electrode is needed in order to harvest the current, so the research team installed a 50nm-thick gold film to get the job done. The gold film sits below a silicone rubber layer composed of thousands of tiny pillars that help create more surface area for skin contact, which in turn creates more friction.


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http://www.extremetech.com/mobile/198519-flexible-nanogenerator-harvests-muscle-movement-to-power-mobile-devices