Abstract: Recently, three-dimensional nickel foam (3D-Nf) has been increasingly studied; however,
further modifications in nanoscale surface modification are necessary for particular applications.
In this work, three-dimensional hierarchically porous nanogranular NiS (NiS-3D-Nf) and wrinkleshaped
NiS (w-NiS-3D-Nf) structures were fabricated directly on nickel foam by a simple one-step
solvothermal process using two different solvents. Several characterization techniques, including
X-ray diffraction pattern, X-ray photoelectron spectroscopy, and scanning electron microscopy, were
used to characterize the samples’ properties. To prove their applicability, supercapacitor electrodes
were tested directly in a three-electrode assembly cell. The resulting w-NiS-3D-Nf electrodes exhibited
greater capacitive activity than the NiS-3D-Nf electrodes. The optimized w-NiS-3D-Nf electrodes
delivered an excellent specific capacitance of 770 Fg􀀀1, at a current density of 1 Ag􀀀1, compared
with the NiS-3D-Nf electrodes (162.0 Fg􀀀1 @ 1 Ag􀀀1), with a cyclic stability of over 92.67% capacitance
retention after 2200 cycles. The resultant unique structure with integrated hierarchical
three-dimensional configuration can not only enhance abundant accessible surface areas but also
produce strong adhesion to the 3D-Nf, facilitating the fast transportation of ions and electrons for
the electrochemical reaction via the conductive 3D-Nf. This set of results suggests that the modification
of 3D-Nf surfaces with a suitable solvent has highly significant effects on morphology, and
ultimately, electrochemical performance. Additionally, the current preparation approach is simple
and worthwhile, and thus offers great potential for supercapacitor applications.