Facile synthesis of NiCo ₂ S ₄ /CNTs nanocomposites for high-performance supercapacitors

Abstract

Herein, porous NiCo2S4/CNTs nanocomposites were synthesized via a simple hydrothermal method followed by the sulphurization process using different sulfide sources. By comparing two different sulfur sources, the samples using thioacetamide as sulfide source delivered more remarkable electrochemical performance with a high specific capacitance of 1765 F g−1 at 1 A g−1 and an admirable cycling stability with capacitance retention of 71.7% at a high current density of 10 A g−1 after 5000 cycles in 2 M KOH aqueous electrolyte. Furthermore, an asymmetric supercapacitor (ASC) device was successfully fabricated with the NiCo2S4/CNTs electrode as the positive electrode and graphene as the negative electrode. The device provided a maximum energy density of 29.44 W h kg−1 at a power density of 812 W kg−1. Even at a high power density of 8006 W kg−1, the energy density still reaches 16.68 W h kg−1. Moreover, the ASC presents 89.8% specific capacitance retention after 5000 cycles at 5 A g−1. These results reveal its great potential for supercapacitors in electrochemical energy storage field.

Multiple structural defects in poor crystalline nickel‐doped tungsten disulfide nanorods remarkably enhance supercapacitive performance

“…Figure 6A displays the representative comparison plots of CV that analyzed samples at 5 mV s À1 of a scans rate. As predicted, the WS 2 /NF NNs and Ni-doped WS 2 /NF NRs samples reveal clear pairs of redox-plots allocated in a range of 0-0.6 V, advising its relatively battery-based actions because of the existence of Ni-doped WS 2 correlated with the redox activities of tungsten, sulfide, and nickel oxidational statings that arose from the possible redox reaction procedures according to the following equations 52,53 :…”

Hierarchical FeCo2S4@FeNi2S4 Core/Shell Nanostructures on Ni Foam for High‐Performance Supercapacitors

“…are observed at 785.4 and 802.0 eV. [20] Figure 2d shows the Fe 2p spectrum, in whicht wo peaks at bindinge nergies of 709.2 and 724.9 eV correspond to Fe 2p 3/2 and Fe 2p 1/2 andt husi ndicate the presence of Fe 2 + . The other peaks at binding energies of 712.5 and 716.5 eV imply the presence of Fe 3 + .…”

“…Besides, two shakeup satellite peaks (Sat.) are observed at 785.4 and 802.0 eV . Figure d shows the Fe 2p spectrum, in which two peaks at binding energies of 709.2 and 724.9 eV correspond to Fe 2p 3/2 and Fe 2p 1/2 and thus indicate the presence of Fe 2+ .…”

NiCo2S4‐Based Composite Materials for Supercapacitors

“…However, their energy density is usually restricted by limited specific capacitance. Compared to pseudocapacitor materials, carbon materials have the merits of good conductivity and ideal cycling stability . The fabrication of composite materials by using carbon materials and pseudocapacitive or battery‐type materials can integrate the merits of the components.…”