Forget lab-made materials like graphene -- natural, old-fashioned hemp may be the ticket to our energy future. Researchers have demonstrated that you can make very efficient carbon electrodes simply by heating hemp bast fibers in a two-stage process. The resulting substance holds as much energy as graphene, but is much cheaper to make. You're just using biological leftovers, after all. It's much more tolerant of temperature extremes, too, and can survive anything from freezing conditions to a scorching 200F. And before you ask -- this is hemp, not pot, so you're not going to get a contact high just by using a battery.

http://www.engadget.com/2014/08/13/hemp-electrodes/