A hierarchical surface-coated 3D-nanoflower network of MoS2 with abundant reaction sites for high-performance asymmetric supercapacitor

Metal vanadate and sulfides are considered the best candidates for energy storage devices thanks to their high conductivity and robust redox properties. Inspired by the excellent electrochemical behavior of nano-flower morphology of MoS2, herein we reported the first-time surface coating of MoS2 with Mg3V2O8. Owing to the excellent conductivity of Mg3V2O8, the surface coating has significant benefits, such as controlling the volume expansion of MoS2, abrupt surface reaction with limited cyclic stability, and a high number of charge trapping sites. The MoS2/ Mg3V2O8 with surface-coated flower-type structure enables the high infiltration rate of electrolytic species which outcome in a high specific capacity of 579 Cg−1. In addition to multi-fold 2D structures, the thin surface coating provides a high number of charge-trapping sites thus enabling the high capacitive response at the electrode interface which is confirmed by Dunn’s Modeling. Considering the high specific capacitance, when integrated with the MoS2/ Mg3V2O8 as an anode in an asymmetric supercapacitor, it can deliver a high energy density of 7.56 Whkg−1 and 4749.75 Wkg−1 power density. The aqueous asymmetric supercapacitor can retain 86.55 % capacitance retention and 92.18 % coulombic efficiency for 10000 GCD cycles. Additionally, the practical viability of the fabricated asymmetric coin cell is tested by powering the commercial calculator for 25 minutes which shows the excellent potential for commercialization. [Display omitted] •3D-surface coated MoS2 nanoflowers with a high number of microchannels enables high electrochemical performance.•The materials with multivalent charged species (Mg, V, Mo, S) can successfully achieve 579 Cg-1 specific capacity.•Asymmetric supercapacitor device (MoS2/Mg3V2O8//AC) achieves the energy density of 7.56 Wh/kg and power density of 4749.75 W/kg.•Reliable cyclic durability by retaining 86.55 % of its capacity and 92.18 % coulombic efficiency after 10,000 GCD cycles.•An asymmetric coin cell is fabricated that can continuously power the commercially available calculator for 25 minutes.