Graphene-anchored NiCoO2 nanoarrays as supercapacitor electrode for enhanced electrochemical performance

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.