Abstract
•CoS2/CNTs nanocomposite was fabricated via hydrothermal and post-annealing approach.•The freestanding design and 3D nickel foam were used to improve the kinetics of the electrochemical reaction.•The CoS2/CNTs@NF electrode showed higher specific capacity (499.8 C g−1) than that of pristine CoS2@NF electrode (387.6 C g−1) at 1 A g−1.•The nanocomposite also exhibit superior rate capability and cyclic-stability than the pristine CoS2 sample.
Electroactive materials with higher surface area, porous structure, higher conductivity, and self-supported design are considered promising candidates for electrochemical applications. The fabrication of an electrode material with a unique design having all the features mentioned above is a major challenge for electrochemical researchers. In this work, pristine CoS2 nanoparticles and CoS2/CNTs nanocomposite have been prepared and decorated directly on nickel foam (NF) using a two-step approach: hydrothermal and post-annealing, for energy storage applications. The CoS2/CNTs@NF electrode shows superior performance as it has a specific capacity (Csp) of 499.8 C g−1 @ 1 A g−1 and excellent cyclic stability of 90.8% after 6000 GCD cycles @ 12 A g−1. The CNTs-supported CoS2 sample displays a minimum capacitance loss of 13.5% by increasing the applied current density from 1 to 12 A g−1, demonstrating its excellent rate-capability. Furthermore, the EIS results show that the value of the charge transfer resistance (RCT) and the mass transfer resistance for CoS2 decreases after its nanocomposite formation with conductive CNTs. The exceptional electrochemical activity of the CoS2/CNTs@NF electrode has been attributed to the synergistic effect of its self-standing design, larger specific surface area, porous-nanostructure, and hybrid composition. The present study provides a new way of designing the electrode material with integrated electrochemical features.
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