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A novel green biosynthesis of the vanadium [email protected] hibiscus sabdariffa ([email protected]) nano-flowers- like structures was successfully synthesized by solvothermal method. The X-ray diffraction analysis of the materials revealed the orthorhombic structure V2O5. No other peaks from the white hibiscus sabdariffa were observed in the XRD pattern which revealing the high phase purity of the [email protected] material. The X-ray photoelectron spectroscopy spectrum of the materials exhibited the presence of V3+, V4+ and V5+ in the binding energies of the [email protected] The electrochemical performance of the electrode material was evaluated using a 6 M KOH aqueous electrolyte. The specific capacity of the [email protected] reached a value of 50.4 mA h g-1 at a current density of 0.5 A g-1. An asymmetric capacitor was also fabricated by adopting an activated carbon negative electrode obtained from the peanut shell waste as raw material and the [email protected] as the positive electrode in 6 M KOH electrolyte. The hybrid capacitor of [email protected]//AC displayed a high energy density of 33 W h kg−1 with a corresponding high power density of 470 W kg−1 at 1 A g−1 in a large voltage window of 0.0 - 1.7 V. The device also exhibited an excellent cycling stability with 87% capacity retention recorded for up to 20.000 constant charging–discharge cycles and an excellent ageing test at a specific current of 10 A g-1.
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