Design and construction of hierarchical Ni3S2 @V-doped NiMn-LDH heterostructure on rGO/Ni foam as an advanced electrode for battery-supercapacitor hybrid devices

Transition metal dopant engineering and rational architecture design have been proven to be effective strategies to improve the electrochemical energy storage properties of electrodes. Herein, V-doped NiMnlayered double hydroxide composites were supported on reduced graphene oxide-coated Ni foam (NMV-L/ rGO) by a hydrothermal method. The influences of V content on the electrochemical performances of NMVL/rGO composites were investigated in detail. At an optimal content of V doping (15%), the NMV-L/rGO-15 reveals enhanced electrochemical properties, and it is subsequently applied as the substrate for the electrodeposition of Ni3S2 layer. Benefiting from the collaborative effect of NMV-L/rGO-15, Ni3S2, and rGO materials, as well as the unique hierarchical architecture, excellent electrochemical performance is obtained in the as-prepared Ni3S2 @NMV-L/rGO-15 composite, which exhibits a high specific capacity of 1412.0 C g-1 at 1 A g-1 as well as desirable long-term stability of 89% over 5000 cycles. Furthermore, the as-fabricated battery-supercapacitor hybrid device (BSH) based on Ni3S2 @NMV-L/rGO-15 and activated carbon (AC) electrodes displays a remarkable energy density of 60.0 W h kg-1 at the power density of 849.1 W kg-1 and superior capacity retention of 96% through 7000 cycles. Such excellent results indicate that the Ni3S2 @ NMV-L/rGO-15 composite holds great potential as electrode material for high-performance BSHs. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

Transition metal dopant engineering and rational architecture design have been proven effective to improve electrode energy storage properties. In this study, V-doped NiMn layered double hydroxide composites showed enhanced electrochemical performance at 15% V doping, leading to the successful electrodeposition of Ni3S2 layer. The resulting Ni3S2 @ NMV-L/rGO-15 composite exhibited excellent electrochemical performance, high specific capacity, and long-term stability, making it a promising electrode material for high-performance battery-supercapacitor hybrid devices.