Manganese dioxide anchored on hierarchical carbon nanotubes/graphene/diatomite conductive architecture for high performance asymmetric supercapacitor

Natural abundant and industrial available biomass diatomite is act as the porous template to in-situ grown graphene layer (G), while the carbon nanotubes (CNTs) arrays are subsequently grown on the graphene surface. The seamless anchored 1D CNTs arrays together with 3D interconnected graphene networks can construct conductive hierarchical framework to enhance the electric conductivity. Furthermore, the enlarged effective surface area of the CNTs/G/diatomite can increase the active material loading amount and facilitate the electrolyte infiltration. Therefore, the MnO2@CNTs/G/diatomite hybrid exhibits a highest specific capacitance of 264.0 F g−1 (based on the MnO2, the value is ~880.0 F g−1), good rate capability and excellent cyclic stability. Moreover, the asymmetric supercapacitor assembled by MnO2@CNTs/G/diatomite and microwave exfoliated graphite oxide reveals a highest energy density of 64.3 W h kg−1 and maximum power density of 19.8 kW kg−1, respectively.