Graphene Double-Layer Capacitor with ac Line-Filtering Performance

Extending the Capability of Supercapacitors

Supercapacitors have porous electrodes that can store more charge per volume in electrical double layers than conventional parallel plate capacitors. However, the porous electrodes cause poor performance in filter circuits that eliminate residual alternating current ripple from rectified direct current. Miller et al. (p. 1637 ) fabricated electrodes with a high surface area for ionic adsorption by growing graphene sheets in the vertical direction off a metal surface. Such capacitors may be able to perform the same filtering tasks as conventional capacitors but take up less space.