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 Mg₃V₂O_8, 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.