Construction of hierarchical NiCoSe@CoS core-shell nanotube arrays for high-performance hybrid supercapacitor

In this work, core-shell NiCoSe@CoS nanotube arrays directly grown on nickel foam were synthesized via two-step hydrothermal method combined with cyclic voltammetry electrodeposition. In such heterostructures, NiCoSe nanotubes as the core were wrapped by interconnected CoS nanosheets as the shell. Results showed that the obtained NiCoSe@CoS nanotube arrays formed a conductive 3D network by growing CoS nanosheets on the surface of the NiCoSe nanotubes, which increased electroactive sites, shortened ion diffusion pathways, and thus enhanced charge storage. The unique core-shell heterostructures improved the structural stability and accelerated the electrode reaction kinetics of the nanotube arrays. Compared with the single-phase CoS nanosheets and NiCoSe nanotube arrays, the NiCoSe@CoS nanotube arrays as electrodes demonstrated enhanced areal capacitance (3.28 and 2.22 F cm-2 at 3 and 30 mA cm(-2), respectively) and cyclic stability (capacity retention rate of 93 % after 5000 cycles at 3 mA cm-2). Furthermore, the NiCoSe@CoS nanotube arrays were used as the positive electrode to assemble hybrid supercapacitor devices with carbon nanotubes as the negative electrode. The fabricated device can deliver an energy density of 36.3 Wh kg(-1) at a power density of 801.7 W kg-1 with long-term cycling stability, which indicates that the NiCoSe@CoS nanotube arrays have a greatly practical application value in supercapacitor devices.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Core-shell NiCoSe@CoS nanotube arrays were synthesized via hydrothermal method and electrodeposition, showing enhanced electrochemical activity, ion diffusion pathways, and charge storage capacity. The heterostructures improved structural stability and electrode reaction kinetics.