▎ 摘　　要

Porous flower-like NiCoO2 and graphene (NiCoO2/rGO) composite nanoarrays were grown directly on Ni foam (NF) without any binders by a simple hydrothermal synthesis method. Due to the porous flowers-like architecture of ultrathin NiCoO2 nanoflakes and the introduction of graphene with the high electrical conductivity, NiCoO2/rGO composite nanoarrays showed superior electrochemical performance including high specific capacity (1286C g(-1) at 0.5 A g(-1)), and good rate capability (1071.5C g(-1), 83.3% capacity retention at 12 A g(-1)). The asymmetric supercapacitor assembled with NiCoO2/rGO and rGO/NF also showed good performance with the energy density of 38.5 Wh kg(-1) at 288 W kg(-1) power density and good cycle stability of 86.9% after 2000 cycles. These results demonstrate the potential application of NiCoO2/rGO composite nanoarrays as a promising electrode material for supercapacitors. (C) 2017 Elsevier Ltd. All rights reserved.