Hierarchical dandelion-like copper oxide wrapped by reduced graphene oxide: Hydrothermal synthesis and their application in supercapacitors

• Dandelion-like CuO wrapped by rGO nanosheets have been prepared.
• The wrapping of rGO contributes to improve the electrochemical performance.
• The CuO-rGO electrode exhibits a specific capacitance of 296 F g−1 at 1 A g−1.
• The capacitive retention reaches 96.1% after 2000 cycles at 2 A g−1.

In this study, reduced graphene oxide (rGO)-wrapped dandelion-like CuO microspheres have been successfully synthesized using a one-step hydrothermal method without calcination. Characterization results demonstrate that dandelion-like CuO microspheres with sizes of 2.0 μm are well wrapped by ultrathin rGO nanosheets. Moreover, the introduced amount of GO dispersion in the reaction system was found to play a key role in tuning the phase compositions and microstructures of the resultant CuO-rGO composites. When used as electrode materials for supercapacitors, dandelion-like CuO wrapped by rGO nanosheets exhibited the best capacitive behavior with a specific capacitance of 296 F g−1 at 1.0 A g−1 and a retention of 96.1% after 2000 cycles at 2.0 A g−1. Such excellent electrochemical performance might be mainly attributed to the rGO wrapping effect, efficiently providing higher electronic conductivity and buffering the volume changes.

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