▎ 摘　　要

NOVELTY - An electrode comprises a graphene scaffold comprising a three-dimensional network of interconnected pores, a first vanadium oxide in a first oxidation state, and a second vanadium oxides in a second oxidation state. The electrode further comprises non-stoichiometric stoichiometric vanadium nanoparticles. The nanoparticles have a particle size of 30nm-70nm, and have a mean particle size ranging from 30nm to 30nm. The concentration of vanadium oxide in the electrode is 5-25 wt.%. The electrode exhibits sharp peaks at 24.4-54.2 when analyzed by X-ray powder diffraction. USE - The electrode is useful in an energy storage device (claimed) such as vanadium flow batteries and rechargeable flow batteries. ADVANTAGE - The electrode: exhibits a large potential window with a high three-electrode specific capacitance of 1,110 F/g; exhibits a high energy density of about 54 Wh/kg with little capacitance loss after 20,000 cycles; and exhibits a very high charge/discharge time and exceptional cycling stability. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: an energy storage device; a method for producing an electrode; and a method for producing an energy storage device. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the energy storage device.