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

Abstract 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.