MOF-Derived Nickel–Cobalt Sulfide Nanoflakes Wrapped Carbon Nanotubes for Hybrid Supercapacitors

Abstract

Transition metal sulfide has been regarded as an ideal electrode material for supercapacitors due to its high energy density. However, the poor cyclic stability caused by low electroconductivity seriously limits its practical application. Herein, carbon nanotubes and nickel−cobalt bimetallic organic framework composites were prepared by the in situ growth method and used as precursors to prepare carbon nanotubes/nickel−cobalt bimetallic sulfide (CNTs/ Ni−Co−S-3) composites. Benefits from the synergy between the components, CNTs/Ni−Co−S-3, as a positive electrode material, presented an extremely high specific capacity of 734 C g −1 at 1 A g −1 and an improved rate capability. Furthermore, when CNTs/Ni− Co−S served as the positive electrode of the hybrid supercapacitor (CNTs/Ni−Co−S-3//AC HSC), the device provided a competitive energy density of 42.15 Wh kg −1 at the power density of 852 W kg −1 and long-term stability (88.46% of specific capacitance retention for 10000 cycles at 8 A g −1 ). This synthesis strategy provides a new pathway for further improving the energy density and cyclic stability of metallic sulfide group composite electrodes.

Synthesis of CNTs Doped Nickel Copper-Sulfides Composite Electrode Material for High-Performance Battery-Supercapacitor Hybrid Device

“…In addition, the shape and large surface area of the nanocomposite have a big impact on how much charge can be stored in them. The NiCuS@CNT nanocomposite exhibits remarkable performance in comparison to other materials due to the combination of these components [45][46][47][48][49][50][51][52][53] in Table I.…”

Recent advances in Ni-materials/carbon nanocomposites for supercapacitor electrodes

“…151 CNTs/Ni–Co sulfide composites exhibited the synergy between the components. It was used by Huang et al 152 as a positive electrode with a high specific capacity of 734 C g −1 in the supercapacitor of CNTs/Ni–Co–S-3//AC HSC with an energy density of 42.15 W h kg −1 and long-term stability. Another study reported an asymmetric fiber-shaped FSC made of carbon fiber, Ni–Co layered double hydroxide, and mono-dispersed CNTs (Ni–Co LDH- x /CNTs- y /CF) as the positive electrode and tremella-derived activated carbon/CF (TDC-z/CF) as the negative electrode.…”

“…The electrochemical properties of supercapacitors on the basis of Ni materials and CNTs composite electrodes are reported in Table 2 144–163 The nanocomposite CNTs/NiCo 2 S 4 showed remarkable capacitive properties. In the structure of the asymmetric supercapacitor, it exhibited energy and power densities of 43.3 W h kg −1 and 800 W kg −1 .…”

“…Ternary nickel cobalt sulfide/oxides and carbon nanotube composites. The electrochemical properties of supercapacitors on the basis of Ni materials and CNTs composite electrodes are reported in Table 2 [144][145][146][147][148][149][150][151][152][153][154][155][156][157][158][159][160][161][162][163] The nanocomposite CNTs/NiCo 2 S 4 showed remarkable capacitive properties. In the structure of the asymmetric supercapacitor, it exhibited energy and power densities of 43.3 W h kg À1 and 800 W kg À1 .…”

MOF-Derived Ultrathin NiCo-S Nanosheet Hybrid Array Electrodes Prepared on Nickel Foam for High-Performance Supercapacitors

“…Moreover, they could provide enough storage charge during their contact reactions with the electrolyte owing to their varieties of chemical valence states [ 8 ]. Sulfur exhibits lower electronegativity than oxygen, making the transition metal sulfide carry lower band gap energy [ 9 ]. Thus, replacing oxygen with sulfur in transition metal compounds could effectively promote electron migration, resulting in the transition metal sulfide as the electrode material demonstrating more excellent electrical conductivity, better electrochemical activity, and higher long-term cycling stability than oxides and hydroxides.…”