Technologically, the nano graphene-based, ionic liquid-enabled supercapacitor provides a specific energy density of 85.6 Wh/kg (based on the total electrode weight) at room temperature and 136 Wh/kg at 80°C, both measured at a current density of 1 A/g (corresponding to a high charge/discharge rate).
a) These are the highest energy density values ever reported for nano carbon material-based supercapaitors dominated by the electric double layer (EDL) mechanism, with minimal contribution from any redox-type pseudocapacitance mechanism.
b) These energy density values are comparable to that of the Ni metal hydride battery. This new technology provides an energy storage device that stores nearly as much energy as in a battery, but can be recharged in seconds or minutes. We believe that this is truly a breakthrough in energy technology.
The theoretical capacitance of graphene is 550 F/g (Farads per gram).