A high energy density all-solid-state asymmetric supercapacitor based on MoS2/graphene nanosheets and MnO2/graphene hybrid electrodes

Abstract

An asymmetric supercapacitor (ASC) with high energy density is designed using flower-like MoS₂ and MnO₂ grown on graphene nanosheets (GNS) as the negative and positive electrodes, respectively. In this paper, flower-like MoS₂/GNS and MnO₂/GNS electrodes were controllably synthesized through a hydrothermal approach. The prepared MoS₂/GNS hybrid displays a typical crinkly and rippled structure with ultrathin MoS₂ nanosheets uniformly grown on the surface of graphene. Additionally, the MoS₂/GNS electrode exhibits superior electrochemical performance, such as high specific capacitance (320 F g⁻¹ at 2 A g⁻¹). The MoS₂/GNS electrode holds great promise as a negative electrode for an ASC due to its high specific capacitance and wide operation window in negative potential. The assembled all-solid-state ASC delivers a remarkable energy density of 78.9 W h kg⁻¹ at a power density of 284.1 W kg⁻¹. Thus the MoS₂/GNS hybrid is a promising electrode material for next-generation storage systems.