Layer-structured nanohybrid MoS2@rGO on 3D nickel foam for high performance energy storage applications

Abstract

This paper describes the synthesis of molybdenum sulfide (MoS₂)@reduced graphene oxide (rGO) on 3D nickel foam via an inexpensive room-temperature two-step method composed of the layer-by-layer (LBL) method followed by solution-based successive ionic layer adsorption and reaction (SILAR). “Self-assembly” growth mechanisms are proposed to discuss the growth of MoS₂ on the rGO to form nanohybrid layered structures. The prepared nanohybrid multilayered structure with a high specific surface area and good electrical conductivity provided a higher specific capacitance of 1071 F g⁻¹ at a current density of 2 A g⁻¹ than that of the bare MoS₂ electrode (661 F g⁻¹ at 2 A g⁻¹), showing an approximately 60% increase in capacitance. The nanohybrid layered structure showed an excellent energy density of 47.6 W h kg⁻¹ and a power density of 7.6 kW kg⁻¹ with a good retention capacity of 95% after 2000 cycles. An asymmetric supercapacitor with MoS₂@rGO as the positive electrode and reduced graphene oxide as the negative electrode delivered a high energy density of 72.8 W h kg⁻¹ at a power density of 7.4 kW kg⁻¹ under an operating voltage window of 1.6 V. This performance was maintained at 92% of the original level at a constant current density of 8 A g⁻¹, even after 4000 cycles. This approach offers a versatile technique for the design and synthesis of metal sulfide nanohybrid structures for electrochemical energy storage devices.