Monocrystalline NiS nanowire arrays supported by Ni foam were synthesized without any surfactant. Characterization results reveal that the as-obtained NiS nanowires belong to a rhombohedral phase with higher aspect ratio. Electrochemical measurements indicate these nanowire arrays can achieve a higher areal capacitance of 8.7 F cm−2 at the current density of 20 mA cm−2, together with good rate capability and excellent cycling stability (78.7% capacitance retention after 8000 cycles).
