Branched carbon nanotube/carbon nanofiber composite for supercapacitor electrodes

We describe the in situ synthesis of branched carbon nanotubes/carbon nanofibers (BCNT/CNF) nanocomposite by a simple chemical vapor deposition method. Electrochemical characterization indicated that the BCNT/CNF based supercapacitors carried a high value of specific capacitance up to 207 F g−1 at a charge/discharge rate of 1 A g−1, which is much higher than branched carbon nanotubes (BCNT) in H2SO4 electrolyte. The supercapacitor showed a very good cycling stability of 95.6% after 5000 charge/discharge cycles at a very high current density of 20 A g−1, and high energy density of 63.7 Wh kg−1 in EMIBF4 organic electrolyte.