Can the motion of checking your smartwatch charge it?

Triboelectric nanogenerators (TENGs) are small devices that convert movement into electricity, and might just be what bring us into an era of energy-harvesting clothes and implants. But could TENGs, even theoretically, give us wearable electronics powered solely by the wearer's day-to-day body motion? The short answer is yes. New research demonstrates the ability of mechanical energy produced by typical body motions to power a watch or smartphone.