Abstract
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 NiMn-layered 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 NMV-L/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 elec-trodeposition of Ni_3S_2 layer. Benefiting from the collaborative effect of NMV-L/rGO-15, Ni_3S_2, and rGO materials, as well as the unique hierarchical architecture, excellent electrochemical performance is obtained in the as-prepared Ni_3S_2 @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 Ni_3S_2@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 Ni_3S_2 @ NMV-L/rGO-15 composite holds great potential as electrode material for high-performance BSHs.
NSTL
Elsevier