Hybrid supercapacitors are energy storage devices that combine the benefits of Li-ion batteries and EDLCs. They consist of a lithium-doped graphite anode and activated carbon cathode. Charging and discharging are achieved both electrochemically like in standard batteries as well as electrostatically, but the cycle life is as high as in EDLCs with rapid discharge rates. The discharge voltage looks very much like an EDLC but it is supported by a minimum voltage. Since hybrid supercapacitors do not contain metal oxides, there is no risk of thermal runaway or combustion.