Your own motion could one day power your cell phone

Looking forward to the day when you don't have to charge your cell phone or activity tracker?
That day might not be as far away as you think.
Researchers at Michigan State University have developed a device they've dubbed a nanogenerator that lets motion charge a mobile device or a wearable.
A cell phone using this technology, for instance, would need no battery. Your own motion would provide power.
"What I foresee, relatively soon, is the capability of not having to charge your cell phone for