Rapid one-step synthesis and electrochemical properties of graphene/carbon nanotubes/MnO2 composites

• RGO/CNT/MnO2 composite was efficiently prepared via a one-step method.
• MnO2 was a nanoneedle-like and well coated on the CNTs and RGO surface.
• The composite exhibited a high specific capacitance of 915 F g−1 of at 0.2 A g−1.
• This is a green route suitable for large-scale production.

A composite consisting of reduced graphene sheets, multi-walled carbon nanotubes, and MnO2 (RGO/CNT/MnO2) was prepared using a facile and efficient one-step method under microwave irradiation. Graphene oxide could be easily reduced without any additional reducing reagents. Potassium permanganate was used as starting materials for the growth of MnO2 on the graphene sheets and carbon nanotubes. Owing to the synergic effect of the ternary component, the electrode exhibited a high rate capacitance, such as 915 F g−1 of specific capacitance at 0.2 A g−1, as well as excellent cycling stability (98.1% capacitance retention after 1500 cycles). On the other hand, the results suggest that our research opens up the possibility for the fabrication of high-performance energy-storage devices of multi-component electrodes.