Hierarchical structure Ni3S2/Ni(OH)2 nanoarrays towards high-performance supercapacitors

Abstract

The rational construction of the active materials with hierarchical structure is a feasible and effective strategy for realizing high electrochemical performance of supercapacitors. Herein, ultra-thin nickel hydroxide nanosheets are directly grow on the external surface of Ni3S2 nanorod arrays grew on nickel foam through simple hydrothermal ways to form Ni3S2/Ni(OH)2 hierarchical nanoarrays. The Ni3S2 nanorod arrays synthesized on nickel foam using hydrogen peroxide as an inducer could not only serve as the main channel for charge transport but also support the growth of active materials, moreover, the exposed active parts can also participate in the electrochemical energy storage process. The external ultra-thin nickel hydroxide nanosheets augment the contact region with the electrolyte and enrich the electrochemical active sites. The Ni3S2/Ni(OH)2 composite exhibits wonderful electrochemical performance is on account of its hierarchical structure could augment the effective specific surface area of electrode materials and induce a synergistic effect between each component. The aquaired Ni3S2/Ni(OH)2 electrode presents a brilliant specific capacitance (826 ​C ​g−1 during 1 ​A ​g−1) and relatively good rate performance (50% retention during 20 ​A ​g−1). In addition, our prepared hybrid supercapacitor used Ni3S2/Ni(OH)2 and AC acted as cathode and anode, respectively, gives rise to a superior energy density of 48.3 ​Wh kg−1 at about 800 ​W ​kg−1 of power density, together with retained about 70% capacitance after 10000 cycles at 5 ​A ​g−1. Meanwhile, two hybrid supercapacitor devices were fabricated in series to power a white LED, which can be continuously lit for more than 8 ​min.