Synthesis of free-standing carbon nanohybrid by directly growing carbon nanotubes on air-sprayed graphene oxide paper and its application in supercapacitor

We report the synthesis of a free-standing two dimensional carbon nanotube (CNT)-reduced graphene oxide (rGO) hybrid by directly growing CNTs on air-sprayed GO paper. As a result of the good integration between CNTs and thermally reduced GO film during chemical vapor deposition, excellent electrical conductivity (2.6 x 10(4) S/m), mechanical flexibility (electrical resistance only increases 1.1% after bent to 90 for 500 times) and a relatively large surface area (3353 m(2)/g) are achieved. Two-electrode supercapacitor assembled using the CNT-rGO hybrids in ionic liquid electrolyte (1-ethyl-3-methylimidazolium tetrafluoroborate) shows excellent stability upon 500 bending cycles with the gravimetric energy density measuring 23.7 Wh/kg and a power density of 2.0 kW/kg. Furthermore, it shows an impedance phase angle of -64.4 degrees at a frequency of 120 Hz, suggesting good potentials for 120 Hz alternating current line filtering applications. (C) 2014 Elsevier Inc. All rights reserved.