New energy storage device charges ahead

2009-03-23T00:00:00-00:00

US researchers believe that they are a step closer to solving the energy storage problem for renewable energy sources and electric vehicles (EVs).

Both EVs and renewable – but intermittent – energy sources, such as solar and wind power, rely on energy storage. Current batteries for EVs don’t yet hold enough energy to cover long distances and are slow to recharge. Similarly, solar and wind power are intermittent and need to be paired with storage devices to provide a useful supply, but the current technology is too expensive and inefficient.

“Conventional devices to store and deliver electrical energy – batteries and capacitors – cannot achieve the needed combination of high energy density, high power, and fast recharge that are essential for our energy future,” explains researcher Gary Rubloff of the University of Maryland.

Ideally, what you want is a combination of high power and high energy density to hold large amounts of energy, provide that energy at high power and be able to recharge rapidly, he says.

Rubloff and his colleagues have developed an energy storage device that improves on the performance of electrostatic capacitors – a device that stores energy as electric charge.

The tiny capacitors consist of a layered structure of metal-insulator-metal thin films. The devices are fabricated in massive arrays using minute holes at a density of 60 billion per square inch.

Electrostatic nanocapacitors formed in film (darker yellow) by sequential deposition of metal (blue), insulator (yellow), and metal. (Credit: A. James Clark School of Engineering, University of Maryland.)

The resulting array of capacitors is up to ten times more efficient than similar existing devices and could open up the way for a new generation of energy storage devices.

“These devices exploit unique combinations of materials, processes, and structures to optimize both energy and power density – combinations that, taken together, have real promise for building a viable next-generation technology, and around it, a vital new sector of the tech economy,” says Rubloff.

The researchers believe that it will be possible to mass produce the devices in panels that could be stacked inside a car battery or integrated into a solar panel.

For further information:
Parag Banerjee, Israel Perez, Laurent Henn-Lecordier, Sang Bok Lee and Gary W. Rubloff. Nanotubular metal–insulator–metal capacitor arrays for energy storage. Nature Nanotechnology (2009), doi: 10.1038/NNANO.2009.37
www.nanocenter.umd.edu/

Afion Media Ltd

New energy storage device charges ahead