New technology may turn car chassis, home walls into batteries

Washington: A future in which our electrical gadgets are no longer limited by plugs and external power sources may be closer.

This intriguing prospect is one of the reasons for the interest in building the capacity to store electrical energy directly into a wide range of products, such as a laptop whose casing serves as its battery, or an electric car powered by energy stored in its chassis, or a home where the dry wall store the electricity that runs the lights and appliances.

It also makes the small, dull grey wafers that graduate student Andrew Westover and Assistant Professor of Mechanical Engineering Cary Pint from Vanderbilt University have made, far more important than their nondescript appearance suggests.

"These devices demonstrate for the first time as far as we can tell that it is possible to create materials that can store and discharge significant amounts of electricity while they are subject to realistic static loads and dynamic forces, such as vibrations or impacts," said Pint.

"All of a sudden, the ability to design technologies at the basis of health, entertainment, travel and social communication will not be limited by plugs and external power sources," Pint said.

The new device is a supercapacitor that stores electricity by assembling electrically charged ions on the surface of a porous material, instead of storing it in chemical reactions the way batteries do.

As a result, supercaps can charge and discharge in minutes, instead of hours, and operate for millions of cycles, instead of thousands of cycles like batteries.

Researchers said that their new structural supercapacitor operates flawlessly in storing and releasing electrical charge while subject to stresses or pressures up to 44 psi and vibrational accelerations over 80 g.

Furthermore, the mechanical robustness of the device doesn't compromise its energy storage capability.

"In an unpackaged, structurally integrated state our supercapacitor can store more energy and operate at higher voltages than a packaged, off-the-shelf commercial supercapacitor, even under intense dynamic and static forces," said Pint.