Facile Synthesis of Graphene@NiO/MoO3 Composite Nanosheet Arrays for High-performance Supercapacitors

Graphene@NiO/MoO3 composite nanosheet arrays (CSAs) were grown on the nickel foam via a one-step hydrothermal way. The composite of NiO and MoO3 showed a promising synergistic effect for capacitors. Graphene had been integrated to the composite nanosheets to further enhance the electrochemical performance. The prepared samples were characterized by scanning electron microscopy and transmission electron microscopy, X-ray diffraction spectroscopy and Raman spectroscopy. A possible growth mechanism was proposed to explain the formation of the composite nanosheets by carrying out a series of time-dependent experiments. Benefiting from the improved electron conductivity and effective buffering of the volume variation induced by redox reactions, the composite exhibited a high area capacitance of 1.372 F cm−2 even at a high current density of 42 mA cm−2, and showed excellent cycle stability (62.7% of the initial capacitance after 7500 cycles, while 87.9% remained in the latter 7000 cycles).