Controlled sulfidation towards achieving core-shell 1D-NiMoO4 @ 2D-NiMoS4 architecture for high-performance asymmetric supercapacitor

Abstract

In this work, nanocomposites with NiMoO4 nanorod as core and NiMoS4 nanosheet as shell with controlled sulfidation manner was obtained by one-step hydrothermal method. Characterization methods like scanning electron microscope and X-ray photoelectron spectrometer confirmed the well-designed core-shell structure and precisely-tuned composition. It exhibited superior electrochemical properties of high specific capacitance (832.3 F g−1 at current density of 5 A g−1), outstanding rate capability and stable cycling performance. With resultant as anode and reduced graphene oxide (rGO) as cathode, an asymmetric supercapacitor (ASC) was assembled and presented high energy density of 22.84 W h kg−1. Besides, cycling performance of the device is so outstanding that the capacity retention was up to 117.4% after 5000 cycles. Benefited from the synergistic effect between NiMoS4 and NiMoO4 components, large specific surface area and effective electron transportation from nanorod @ nanosheet structure, the excellent electrochemical performance indicates a good prospect of the material in the energy storage field.