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

•Direct growth of carbon nanotubes by chemical vapor deposition on air-sprayed graphene oxide paper.•Two-dimensional carbon nanohybrid with excellent conductivity and mechanical flexibility.•Supercapacitor with excellent performance stability upon mechanical deformation for flexible electronics applications.•Supercapacitor with high impedance phase angle for 120 Hz alternating current line filtering applications.

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 (2.6×104 S/m), mechanical flexibility (electrical resistance only increases 1.1% after bent to 90° for 500 times) and a relatively large surface area (335.3 m2/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° at a frequency of 120 Hz, suggesting good potentials for 120 Hz alternating current line filtering applications.

Graphical abstractFlexible and highly conductive carbon nanotube-reduced graphene oxide nanohybrid.Figure optionsDownload full-size imageDownload as PowerPoint slide