Carbon nanotubes/activated carbon hybrid with ultrahigh surface area for electrochemical capacitors

A hybrid carbon materials with three dimensional network carbon nanotubes in activated carbon was prepared by an in situ activation process. This hybrid carbon material has ultrahigh specific surface area (2879 m2/g), pore volume (1.36 cm3/g) and developed small mesopore network, which is very favorable for fast electrolyte ion transport in the porous channel. As evidenced by N2 adsorption, cyclic voltammetry and electrochemical impedance measurements, the hybrid carbon material shows superior capacitive behaviors (exhibiting a high capacitance of 140 F/g, better capacitance retention ratio of 80% even at very high sweep rate of 200 mV/s) and provides much higher power density while still maintaining good energy density. This hybrid carbon material offers a great potential in electrochemical capacitors, particularly for applications where high power output and good high-frequency capacitive performances are required.