'Nanoscoops' could lead to new battery technology

Posted by Emma Woollacott

New batteries based on an entirely new type of nanomaterial are claimed to charge more than 40 times faster than today’s lithium-ion batteries.

The high-power rechargeable lithium (Li)-ion batteries developed at Rensselaer Polytechnic Institute would have applications in electric automobiles, as well as laptops, mobile phones and other portable devices.

The new material, dubbed a 'nanoscoop' because of its ice cream-cone shape, can cope with extremely high rates of charge and discharge that would cause conventional electrodes to rapidly deteriorate and fail.

It can be charged and discharged at a rate 40 to 60 times faster than conventional battery anodes, while maintaining a comparable energy density.

"Charging my laptop or cell phone in a few minutes, rather than an hour, sounds pretty good to me," says Professor Nikhil Koratkar. "By using our nanoscoops as the anode architecture for Li-ion rechargeable batteries, this is a very real prospect. Moreover, this technology could potentially be ramped up to suit the demanding needs of batteries for electric automobiles."

Batteries for all-electric vehicles must deliver high power densities in addition to high energy densities, Koatkar said. Today, supercapacitors perform power-intensive functions such as starting the vehicle and rapid acceleration, with conventional batteries delivering high energy density for normal cruise driving and other operations.

Koratkar says the invention of nanoscoops may enable these two separate systems to be combined into a single, more efficient battery unit.

Most batteries in today’s portable electronic devices are deliberately designed to charge very slowly, in order to protect the battery from stress-induced damage.

The Rensselaer team’s nanoscoop, however, was engineered to withstand the buildup of stress. Made from a carbon nanorod base topped with a thin layer of nanoscale aluminum and a 'scoop' of nanoscale silicon, the structures are flexible and able to quickly accept and discharge lithium ions at extremely fast rates without sustaining significant damage.

The nanoscale size of the scoop is also vital since nanostructures are less prone to cracking than bulk materials, according to Koratkar.

"Due to their nanoscale size, our nanoscoops can soak and release lithium at high rates far more effectively than the macroscale anodes used in today’s Li-ion batteries," he says.

"This means our nanoscoop may be the solution to a critical problem facing auto companies and other battery manufacturers – how can you increase the power density of a battery while still keeping the energy density high?"