A report published in the journal Scientific indicates that a team of scientists at Vanderbilt University in the US have successfully fabricated a new design of supercapacitor using silicon-based electrodes. Super capacitors are traditionally made from activated carbon to give them the large surface area necessary to store charge. Silicon was not thought suitable because it reacts with chemicals in the electrolytes used to provide ions which store the electrical charge.

 

The team headed by Assistant Prof. Carl Pint started by etching optimal supercapacitor nanostructures onto the surface of silicon. Pint’s group then attempted to coat the porous silicon surface with carbon to provide insulation from the electrolyte. “We had no idea what would happen,” said Pint. “Typically, researchers grow graphene from silicon-carbide materials at temperatures in excess of 1400 degrees Celsius. But at lower temperatures – 600 to 700 degrees Celsius – we didn’t expect graphene-like material growth.”

When the porous silicon came out of the furnace they found the structure looked nearly identical to the original material but was coated by a layer of graphene a few nanometers thick. This new technique allows supercapacitors to be incorporated into the design of all sorts of components during the chip fabrication process.