▎ 摘　　要

Supercapacitors with superior performance and long cycling ability are attractive for the next-generation energy storage devices. Herein, an unique hybrid of nickel hydroxide carbonate nanobelts densely and strongly anchored on reduced graphene oxide nanosheets (HC/RGO) has been designed and synthesized through a facile hydrothermal approach. The as-prepared HC/RGO composites display a nearly two-dimensional architecture. Electrochemical investigation shows that the HC/RGO composite electrode has a maximum specific capacitance of 1662.4 F/g (3.5 F/cm(2)) at 1.0 A/g with excellent rate capability (64.7% capacitance retention when increasing the current density from 1.0 to 10.0 A/g) and good cyclic stability. The outstanding electrochemical property of HC/RGO composite electrode is possibly attributed to the intrinsic nature of Ni-2(OH)(2)(CO3), the conductive RGO support, and the ultrathin thickness of Ni-2(OH)(2)(CO3) nanounits which can accelerate the electron transport and facilitate the redox reactions. This hydroxycarbonate-based hybrids with excellent electrochemical performance provide an new avenue for designing high-performance supercapacitor electrodes.