Highly efficient asymmetric supercapacitor-based on Ni-Co oxides intercalated graphene as positive and Fe2O3 doped graphene as negative electrodes

•The fabricated ternary nanocomposite demonstrated an excellent pseudocapacitive behaviour.•The Fe2O3@rGO greatly enhanced the capacitance performance for negative electrode.•Synergistic design of asymmetric cell delivered a long lifespan time.•The assembled ASCs achieved high energy density of 37.83 Wh kg−1 at 750 W kg−1 . Asymmetric supercapacitor (ASC) technique is introduced as promising and efficient energy storage devices due to their fast charging process and high-power density. A simple and green approach was introduced to fabricate mixed Co3O4/NiO intercalated reduced graphene oxide (rGO) nanosheets as ternary nanocomposite electrode materials for ASC applications. Herein, a Co3O4/NiO/rGO ternary nanocomposite was successfully fabricated using a hydrothermal method. The field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were utilized to elucidate the morphological shape and chemical surface analysis for the fabricated materials. Comparing the prepared samples, the ternary nanocomposite demonstrated a good capacitance value of 485.6 F/g at a current density of 2 A/g, good cycling stability, and low equivalent series resistance. The ASC was assembled using the Co3O4/NiO/rGO electrode as positive electrode and Fe2O3/rGO binary composite as the negative electrode. The proposed configuration design of ASC achieved a high energy density (37.83 W h /kg) at a high-power density of (750 W/kg) and a long life-time (86.9%) of over 6000 cycles. The ASC configuration design of Co3O4/NiO/rGO nanocomposites//Fe2O3/rGO opens new doors for promising green, economic, and efficient material-based supercapacitors. [Display omitted]