Two-step in-situ hydrothermal synthesis of nanosheet-constructed porous MnMoS4 arrays on 3D Ni foam as a binder-free electrode in high-performance supercapacitors

Abstract The structural engineering of electrode material for improving their electrochemical performance plays an essential role in better development in energy storage technology. In the present study, nanosheet-constructed porous MnMoS4 arrays were in-situ grown on 3D nickel foam substrate to investigate its electrochemical behavior in supercapacitors. Nickel foam, due to its favorable electrical conductivity, low weight, three-dimensional structure and high surface area was selected as the substrate in this study. MnMoS4 nanosheets (NSs) were synthesized in two in-situ hydrothermal steps. In the first step, the MnMoO4 and in the second step the MnMoS4 were synthesized using an oxide precursor. The physicochemical characteristics of MnMoS4 NSs were investigated by various techniques such as field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray energy diffraction (EDX), X-ray diffraction (XRD), Fourier transform infrared (FT–IR) and Raman spectroscopy. Particularly, the obtained MnMoS4 nanosheet arrays on the nickel foam electrode illustrate significant electrochemical activity owing to their desirable structural and compositional attributes. The as-prepared electrode delivers a maximum gravimetric specific capacitance of 1865.2 F g–1 at the current density of 1 A g–1 with elevating cycling stability of 89.22 % capacitance retention after 3000 cycles. Interestingly, the asymmetric supercapacitor (ASC) assembled with the MnMoS4 nanosheet arrays and activated carbon (AC) electrodes exhibit an energy density of 58.03 Wh kg−1 at a power density of 770 W kg−1. The results show that the manganese molybdenum sulfide is a hopeful electrode material for the feasible application.