Jun 19, 2013
Graphene QDs on aligned carbon nanotubes ramp up supercapacitor performance
Supercapacitors containing graphene quantum dot (GQD) assemblies on horizontally aligned carbon nanotubes (HACNTs) have been prepared by scientists from Beijing Institute of Technology (BIT). The hybrid arrays exhibited a high capacitance of 44 mF/cm2, representing more than 200% improvement over that of bare HACNT electrodes.
To make the device, super-long vertically aligned CNTs (VACNT) were first synthesized by water-assisted chemical vapor deposition (CVD) and then transformed into HACNTs using a roller. Next, through an electrochemical deposition process, GQDs were uniformly anchored on the surface of the CNTs, which produced a porous structure. Finally, the as-synthesized GQD/CNT composite film was assembled in a symmetrical two-electrode configuration to fabricate a supercapacitor.
The device retained its initial capacitance after 1,000 charge-discharge cycles and no obvious degradation in the capacitance could be observed during the cycling experiment. This confirms the good affinity of electrodeposited GQDs to the HACNT scaffolds.
Full details can be found in the journal Nanotechnology.
About the author
The study was performed by researchers from Beijing Institute of Technology (BIT), China. Yue Hu is a PhD candidate in the School of Chemistry at BIT. She conducted the controlled assembly of GQDs on HACNTs and studied the properties of the device as a supercapacitor. Zhipan Zhang is an associate professor at BIT and his research interest lies in energy conversion/storage devices, particularly solar-related. Liangti Qu is head of the functional nanostructure chemistry group at BIT, whose research is mainly focused on nanochemistry, advanced functional materials and functional devices. Topics include the controlled synthesis of new functional nanomaterials, as well as assembly processes and applications in various areas.