Summary: Scientific American: Power Paper: Energy Storage by the Sheet http://www.sciam.com/print_version.cfm?articleID=61525146-E7F2-99...
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August 14, 2007
Power Paper: Energy Storage by the Sheet
By surrounding carbon nanotubes with cellulose, researchers have devised a flexible, paper-thin
Could paper be the future of power in electronic gadgetry? Just as plastics unleashed a revolution in the
manufacture of everyday materials, a new power source composed of cellulose, carbon nanotubes and a
dash of liquid salts could revolutionize the energy behind gadgets from iPhones to pacemakers.
"We have a paper battery, supercapacitor and battery-supercapacitor hybrid device that could be used in a
variety of energy storage applications," says biological and chemical engineer Robert Linhardt of Rensselaer
Polytechnic Institute (R.P.I.) in Troy, N.Y., who helped lead the team that made the discovery. "These devices
are lightweight and flexible and are primarily composed of cellulose paper--an environmentally friendly and
A collaboration between three labs at R.P.I.--biopolymers, nanotubes and electronics--the power paper
works by using cellulose to separate aligned carbon nanotubes functioning as electrodes. The nanotubes are
grown and the cellulose is dissolved in an electrolyte--in a regular battery (sulfuric) acid is used, but in this
case a room-temperature ionic liquid (otherwise known as a liquid salt)--is poured around it. After drying, a
thin sheet of "nanocomposite paper" is left that "can be rolled up, twisted or bent to any curvature," the
researchers write in Proceedings of the National Academy of Sciences USA.