Solvothermal synthesis of NiCo-layered double hydroxide nanosheets decorated on RGO sheets for high performance supercapacitor

•Ni–Co LDH/RGO composites were synthesized through a facile solvothermal approach.•Porous Ni–Co LDH nanosheets decorated on RGO sheets homogeneously.•The Ni–Co LDH/RGO composite exhibits excellent capacitive performance.•Possible mechanism for the enhanced capacitive performance was proposed.

Highly uniform composites composed of NiCo-layered double hydroxide (NiCo-LDH) and reduced graphene oxide (RGO) were successfully fabricated through a facile one-pot solvothermal method. The resulting composites (NiCo-LDH/RGO) display nanosheet architecture with tunable content of NiCo-LDH. By virtue of the greatly enhanced rate of electron and mass transfer as well as the improved specific surface area, the as-obtained NiCo-LDH/RGO composite electrodes exhibit excellent supercapacitive properties, and deliver a maximum specific capacitance of 1911.1 F g−1 at the current density of 2.0 A g−1. Moreover, at the high current density of 20 A g−1, the specific capacitance of NiCo-LDH/RGO nanocomposite still remains as high as 1469.8 F g−1, indicating an extraordinary rate capability. Good cycling stability with the capacitance retention of 74% is obtained after repeating the charge–discharge measurements for 1000 cycles at the current density of 20 A g−1. The combination of the high capacity of pseudocapacitive double hydroxides and good conductivity of RGO make the NiCo-LDH/RGO composites promising candidates for electrode materials in energy storage and conversion devices.