Construction of layered C@MnNiCo–OH/Ni3S2 core–shell heterostructure with enhanced electrochemical performance for asymmetric supercapacitor

Abstract

Transition metal hydroxides with three-dimensional heterostructure have been proved to be promising candidates as the electrode materials for energy storage. Herein, a layered C@MnNiCo–OH/Ni3S2 core-shell heterostructure, composed of grass-like Ni3S2 nanosheets, interlaced ultrathin MnNiCo–OH nanosheets and the coated amorphous carbon, has been successfully designed and synthesized by the facile hydrothermal and electrodeposition processes, which exhibits superior electrochemical performance. The unique core-shell structure is conductive to enlarge the active sites and provide charge transfer rate and redox reactions. The specific capacitance of the C@MnNiCo–OH/Ni3S2/NF electrode could reach 2332 mF cm−2 at 1 mA cm−2 and reserves 89.45 % capacitance after 5000 continuous cycles. Besides, the two-electrode device assembled by C@MnNiCo–OH/Ni3S2/NF and activated carbon (C@MnNiCo–OH/Ni3S2/NF//AC) shows an excellent density of 73.84 Wh kg−1 at 800 W kg−1. The remarkable performances make it possible for the C@MnNiCo–OH/Ni3S2/NF nanocomposite to apply in the area of conversion and energy storage.