Etching holes in graphene supercapacitor electrodes for faster performance

Graphene is being widely investigated as a material to replace activated carbon in supercapacitor (electrochemical capacitor) electrodes. Supercapacitors have much higher energy density, but are typically slow devices (similar to 0.1 Hz) compared to other types of capacitors. Here, top-down semiconductor processing has been applied to graphene-based electrodes in order to fabricate ordered arrays of holes through the graphene electrodes. This is demonstrated to increase the speed of the electrodes by reducing the ionic impedance through the electrode thickness. This approach may also be applicable to speeding up other types of devices, such as batteries and sensors, that use porous electrodes.