Abstract:
Few-layer graphene was synthesized on a
nickel foam template by chemical vapor deposition. The
resulting three-dimensional (3D) graphene was loaded with
nickel oxide nanostructures using the successive ionic layer
adsorption and reaction technique. The composites were
characterized and investigated as electrode material for
supercapacitors. Raman spectroscopy measurements on the
sample revealed that the 3D graphene consisted of mostly
few layers, while X-ray diffractometry and scanning electron
microscopy revealed the presence of nickel oxide. The
electrochemical properties were investigated using cyclic
voltammetry, electrochemical impedance spectroscopy,
and potentiostatic charge–discharge in aqueous KOH
electrolyte. The novelty of this study is the use of the 3D
porous cell structure of the nickel foam which allows for
the growth of highly conductive graphene and subsequently
provides support for uniform adsorption of the NiO onto
the graphene. The NF-G/NiO electrode material showed
excellent properties as a pseudocapacitive device with a
high-specific capacitance value of 783 F g-1 at a scan rate
of 2 mV s-1. The device also exhibited excellent cycle
stability, with 84 % retention of the initial capacitance after
1000 cycles. The results demonstrate that composites made using 3D graphene are versatile and show considerable
promise as electrode materials for supercapacitor
applications.
