Another group of US (Californian) scientists have been working on the use of graphene and CNT's to develop more efficient supercapacitors for energy storage (see article entitled Graphene and CNT Hybrid Supercapacitor )
They have deposited graphene on a nanoscale carbon nanotube porous foam that provides the high surface area that the electrolyte infiltrates. The foam is formed from a nickel substrate with graphene and CNT's vapour deposited before the sucessive deposition of nanoparticles of ruthenium oxide.
The specific energy and power density are reported as twice that of commercial supercapacitiors.
There is a free access paper in the journal Nature Scientific Reports