Electric cars and laptops may soon benefit from a prototype capacitor that can store power as densely as a supercapacitor, and release it rapidly.

The novel capacitor has been developed by a team of scientists from the University of Maryland and the Korea Advanced Institute of Science and Technology.

Gary Rubloff, a chemist at the University of Maryland, says that the secret to the prototype's performance is that it has 10 billion tiny capacitors crammed into every square centimetre.

Electrodes connect up the mini devices so they can function as a single unit, the researcher adds.

Rubloff has revealed that the prototype capacitor can deliver energy at a speed typical of electrostatic capacitors, at a rate that would allow a single kilogram to deliver one megawatt of power, which is enough to power 10,000 100-watt light bulbs.

The researcher further says that the capacitor can also store energy as densely as a supercapacitor, with 1 kg holding 2500 joules.

"Our primary target (for this technology) is as part of a hybrid battery-capacitor system for electric cars. But there are many (potential) small scale applications, (including) better electrical storage systems for cellphones or laptops," New Scientist magazine quoted Rubloff as saying.

A research article on the creation of the new prototype capacitor has been published in the journal Nature Nanotechnology.