Teen's invention could charge your phone in 20 seconds


Waiting hours for a cellphone to charge may become a thing of the past, thanks to an 18-year-old high-school student’s invention. She won a $50,000 prize Friday at an international science fair for creating an energy storage device that can be fully juiced in 20 to 30 seconds. The fast-charging device is a so-called supercapacitor, a gizmo that can pack a lot of energy into a tiny space, charges quickly and holds its charge for a long time. What’s more, it can last for 10,000 charge-recharge cycles, compared with 1,000 cycles for conventional rechargeable batteries, according to Eesha Khare of Saratoga, Calif.