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 ... 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 [type of] 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 [the inventor] Eesha Khare of Saratoga, Calif. Supercapacitors also allowed her to focus on her interest in nanochemistry - really working at the nanoscale to make significant advances in many different fields." To date, she has used [her] supercapacitor to power a light-emitting diode, or LED. The invention's future is even brighter. She sees it fitting inside cellphones and the other portable electronic devices that are proliferating in today's world, freeing people and their gadgets for a longer time from reliance on electrical outlets. "It is also flexible, so it can be used in rollup displays and clothing and fabric," Khare added. "It has a lot of different applications and advantages over batteries in that sense." Khare's invention won her the Intel Foundation Young Scientist Award at the Intel International Science and Engineering Fair, conducted ... in Phoenix, Ariz.