▎ 摘　　要

Synthesis of high-quality graphene nanosheets under eco-friendly strategies is of enormous interest today hence graphene-based materials offer unique advantages in a wide range of applications including light-weight supercapacitors. The reduction of graphene oxide (GO) by chemical reagents frequently involves hazardous reductants that are also dangerous to humans. In view of sustainability, we develop a facile and green procedure to synthesize soluble-graphene by reducing the GO in delphinium root extraction for the first time. The reducing property of organic compounds that exist in the aqueous delphinium root extract may be accountable for the reduction of exfoliated GO to D-graphene under reflux condition. The efficient elimination of oxygen functionalities from GO was verified by powder X-ray diffraction (PXRD), UV-Visible spectroscopy (UV-Vis), Fourier transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS) studies. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) studies indicate the successful development of few-layer graphene. The electrochemical activities are delivered by cyclic voltammetry (CV) and galvanic charge-discharge (GCD) studies. This uniquely-synthesized D-graphene electrode offers superior electrochemical performance at 2 A g(-1) with an utmost specific capacitance (C-s) of 158 F g(-1) and high energy density (E) of 22 Wh Kg(-1). Taking the above remarkable results, the characteristics of eco-friendly, easy synthesis and cheap endow this green approach as a promising avenue for the exploitation of graphene-based materials in numerous applications, particularly for graphene-based light-weight supercapacitors.