Template-Assisted Synthesis of Nickel Sulfide Nanowires: Tuning the Compositions for Supercapacitors with Improved Electrochemical Stability

Ni nanowires were first synthesized via a chemical method without surfactants or a magnetic field. A series of nickel sulfide nanowires (Ni₃S₂-Ni, Ni₃S₂-NiS-Ni, and Ni₃S₂-NiS) have been successfully prepared by a controlled sacrificial template route based on the conductive Ni nanowire template. Electrochemical characterizations indicate that Ni₃S₂-NiS nanowires present superior redox reactivity with a high specific capacitance of 1077.3 F g^-1 at 5 A g^-1. Besides, its specific capacitance can remain about 76.3% after 10 000 cycles at 20 A g^-1. On the contrary, the nickel-preserving sulfide nanowires (Ni₃S₂-Ni and Ni₃S₂-NiS-Ni) deliver enhanced cycling stability as 100% of the initial specific capacitance of Ni₃S₂-Ni is retained after 10 000 cycles. The outstanding electrochemical stability can be attributed to the interaction between nickel sulfides and the conductive nickel nanowires.