Cathodic Deposition of Flaky Nickel Sulfide Nanostructure as an Electroactive Material for High-Performance Supercapacitors

In this current work, a flaky nickel sulfide (Ni3S2) nanostructure was deposited on a Ni foam substrate using a facile potentiodynamic deposition approach and investigated as an electroactive material for high-performance supercapacitor for the first time. X-ray diffraction, scanning electron microscopy and transmission electron microscopy confirmed that the as-prepared Ni3S2 nanostructure was assembled from intercrossing nanoflakes, thus facilitating the electrolyte penetration. The flaky Ni3S2 nanostructure showed a high specific capacitance as well as 717 F g−1 at 2 A g−1, and a remarkable rate capability, in which a promising specific capacitance of 411 F g−1 can still be delivered at 32 A g−1. Moreover, the flaky Ni3S2 nanostructure demonstrated an impressive excellent cycling performance that ∼91% of retention in the specific capacitance can still be made after cycling of 500–1000 consecutive charge/discharge tests at a relatively high current density of 4 A g−1. As a result, the flaky Ni3S2 nanostructure can be considered as a promising electroactive material for high-performance SCs.