CVD based synthesis of binder free nanostructured MgS/MoS2@NiF electrode material for asymmetric supercapacitor applications

•Nanoneedles like MgS/MoS2@NiF EMs are synthesized by simple CVD technique.•MgS/MoS2@NiF EMs has Csp = 9149 Fg-1, Csp retention = 98.2 % after 10,000 cycles.•Synthesized EMs is exhibited excellent physicochemical-stability after 10,000 cycles.•ASC device displayed Csp = 701 Fg-1, Ed = 288–151 Whkg-1, Pd = 3440–21,500 Wkg-1.•ASC device presents the Coulombic efficiency of 100 % after 10,000 cycles. Two-dimensional molybdenum disulfide (MoS2) electrode materials (EMs) have gained significant interest due to their remarkable electrochemical performance in renewable energy storage devices (RESDs). However, the layered agglomeration decreases the EMs practical applications in RESDs. By combining with transition metal sulfide, layered agglomeration and electrochemical performance can be improved violently. Therefore, in this research work, MoS2-based magnesium sulfide (MgS/MoS2) nanostructured EMs are synthesized on nickel foam (NiF) via a chemical-vapor-deposition (CVD) technique. The synthesis of MoS2 and heterostructured MgS/MoS2@NiF EMs having cluster of nanoparticles and nanoneedles like microstructure is confirmed by field emission scanning electron microscopic analysis. The surface area (170 m2g-1) of nanoneedles based MgS/MoS2@NiF EMs is significantly higher than the surface area (60 m2g-1) of nanoparticles based MoS2@NiF EMs, causes to increase the electrocheomical performance of the syntehsized EMs. The MgS/MoS2@NiF EMs is preserved maximum specific capacitance of 9149 Fg-1 at 10 Ag-1, energy density of 234–171 Whkg-1, power density of 2150–4300 Wkg-1 and capacitance retention of 98.2 % for 10,000 cycles. The cyclic voltammetric study is indicated that the EMs have pseudocapacitive nature (diffusion process) which is increased by addition of MgS layer over MoS2 surface. The shifting of impedance profile to y-axis confirmed the increasing diffusion rate of ions in the pores of MoS2 by the addition of MgS layer. The theoretical Dunn's model also revealed that the over-all current produced by the synthesized EMs is due to the current contribution of diffusive and capacitive controlled process. The asymmetric supercapacitor (ASC) device preserved pseudocapacitive nature with maximum specific capacitance of 701 Fg-1 at 4 Ag-1. Moreover, the ASC device is presented the energy density ranged from 288 to 151 Whkg-1, power density ranged from 3440 to 21,500 Wkg-1, Coulombic efficiency of 100 % and capacitance retention of 95 % for 10,000 cycles performed at 20