If we pursue the road towards the full electric car, we must find ourselves the energy storage that can bear at least the power of gasoline. As far as today, batteries, supercapacitors and hydrogen have been the ways to follow for powering an electric car. Of the three, the supercapacitors have a great advantage: they can charge and discharge very quickly, giving instant torque to the electric car’s motor.
The chemist Gary Rubloff from the University of Maryland, and colleagues from the Korea Advanced Institute of Science and Technology have invented a new type of electricity storage, combining electrostatic capacitors with supercapacitors. Electrostatic capacitors are made of a sandwich-like structure of two conducting plates separated by an insulating layer, and have the advantage of fast storing and releasing of the electricity.
Rubloff’s idea was to built 10 billion nanometric capacitors, each having 50 nanometers across. They are made by adding a surface layer of oxide to a sheet of aluminium foil to create a regularly spaced array of nanopores across its surface. Each pore is then filled with three nested, concentric layers of material that function as the traditional conductor-insulator-conductor arrangement of an electric capacitor.
The conducting layers are made from titanium nitride, and the insulating layer from aluminium oxide. They are laid down with a highly precise way of depositing nanoscale structures called atomic layer deposition.
The capacitor’s discharge speed is of about 1 MW/kg/second. If this speed would be applied to a normal electric car’s motor, it would melt it in a second. Seems strong enough to me. Still, the team is continually tweaking their invention to get the most out of it.