Brett Smith for redOrbit.com – Your Universe Online
Because space within today’s electronic devices is at a premium and these devices are requiring more and more power – engineers have been looking into making batteries that are also the cases of devices or possibly the exteriors of electric vehicles.
According to a new study published in the journal Nano Letters, engineers at Vanderbilt University have developed small, grey wafers that could be the forerunner of these new types of batteries.
“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 study author Cary Pint, an assistant professor of mechanical engineering at Vanderbilt University.
The novel device is actually a supercapacitor that holds electricity by cobbling together charged ions on the surface of a porous material instead of holding it in chemicals as conventional electric batteries do now. Consequently, supercapacitors may charge and release in minutes, as opposed to hours, and function for millions of cycles as opposed to thousands of cycles like conventional batteries.
In the report, the researchers stated that their design functions perfectly in storing and releasing a charge as it is being subjected to pressures up to 44 pounds per square inch and vibrational accelerations much higher than those acting on turbine blades in a jet engine.
Pint said the robust nature of the novel device does not compromise its performance.
“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,” Pint said.
One major drawback with supercapacitors is the fact that they must be larger and heavier than lithium-ion batteries to store the same amount of energy. However, Pint said this supposed drawback isn’t so bad considering what ‘supercaps’ might be used for in the future.
“Battery performance metrics change when you’re putting energy storage into heavy materials that are already needed for structural integrity,” Pint said. “Supercapacitors store ten times less energy than current lithium-ion batteries, but they can last a thousand times longer. That means they are better suited for structural applications. It doesn’t make sense to develop materials to build a home, car chassis, or aerospace vehicle if you have to replace them every few years because they go dead.”
The energy-storing wafers consist of electrodes made from silicon, which is best suited for consumer devices and solar cells. However, the study researchers said that their design will probably carry over to other materials, such as carbon nanotubes and metals like aluminum.
The US Department of Energy’s Advanced Research Project Agency for Energy (ARPA-E) is currently investing $8.7 million in study projects that concentrate expressly on integrating energy storage into structural materials. While there have been new reports of other attempts to create multifunctional materials or structural batteries, there have not been any published studies on tests performed with these storage materials that indicate how they perform under practical mechanical loads, Pint said.
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