A device that generates electricity through contact and friction might one day be used to harvest the energy from human motion to charge portable electronics.
Zhong Lin Wang and his colleagues at the Georgia Institute of Technology in Atlanta designed a compact, light-weight generator (pictured), consisting of a copper-plated disk that spins and rubs against a static base containing a layer of electrodes and a conducting surface. The device can harvest mechanical energy from gentle wind, tap-water flow and normal body movements.
The technology could be developed for large-scale power generation, the authors say.
Nature Commun. 5, 3426 (2014) http://dx.doi.org/10.1038/ncomms4426