Ultracapacitors Based on Nano-fiber Electrodes

Electrochemical capacitors, sometimes called ultracapacitors, or supercapacitors, are of interest for hybrid electric vehicles and other automotive electronic and military systems. To be cost and weight effective compared to batteries, they must combine adequate specific energy and specific power with long cycle life, and meet cost targets as well. Hyperion's commercial nanotube product, Graphite Fibrils', with a high available surface area of 200 sq.m/gm, has been initially measured to have a capacitance of 86 F/gm. This contains a substantial Faradaic contribution. It is proposed in Phase I to enhance Faradaic contributions via post treatment of the nanotubes. Phase II will use the Phase I results to design, fabricate and test electrochemical capacitors.