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Supercapacitors that can deliver a strong surge of electrical power could be manufactured from carbon nanotubes using a technique developed by researchers at ΢²ªÊÓƵ.

Supercapacitors are electrical storage devices that can deliver a huge amount of energy in a short time. Hybrid-electric and fuel-cell powered vehicles need such a surge of energy to start, more than can be provided by regular batteries. Supercapacitors are also needed in a wide range of electronic and engineering applications, wherever a large, rapid pulse of energy is required.

Ning Pan, a professor of textiles in the Department of Biological and Agricultural Engineering and the Nanomaterials in the Environment, Agriculture and Technology (NEAT) center at ΢²ªÊÓƵ, postdoctoral researcher Chunsheng Du and Jeff Yeh of Mytitek Inc. of Davis prepared suspensions of carbon nanotubes -- tiny rolled-up cylinders of carbon just a few atoms across. They developed a method to deposit the nanotubes on nickel foil so that the nanotubes were aligned and packed closely together.

Conventional, or "Faraday" capacitors, store electrical charges between a series of interleaved conducting plates. Because of their small size, the nanotubes provide a huge surface area on which to store and release energy, Pan said.

The new devices can produce a power density of 30 kilowatts per kilogram (kW/kg), compared with 4 kW/kg for the most advanced devices currently available commercially, Pan said. Other researchers have described laboratory supercapacitors capable of up to 20 kW/kg, he said.

The work is published in the Feb. 1 issue of the journal Nanotechnology.