Abstract
Energy crises have prompted researchers to develop new electrode materials for efficient energy storage, leading to the creation of effective energy storage devices. Therefore, this study introduces Ni-doped ZnSe/rGO-based materials fabricated through a hydrothermal synthesis method, which demonstrated enhanced electrical and electrochemical performance. X-ray diffraction (XRD) analysis revealed an increase in the crystallite size from 49.72 nm to 96.74 nm, accompanied by a corresponding growth in the particle size, which can be attributed to the incorporation of Ni and rGO as substituents. The electrochemical characterization of all fabricated electrodes indicated that the best-performing Zn(0.90)Ni(0.10)Se/rGO composite achieved a high specific capacitance of 1920.20 F g(-1) at 5 mV s(-1), significantly surpassing that of pure ZnSe (346.8 F g(-1)), as determined from CV measurements. Additionally, the Zn(0.90)Ni(0.10)Se/rGO electrode demonstrated excellent cycling stability (90.85% capacitance retention after 10 000 cycles), a high power density of 3500 W kg(-1) at a current density of 7 A g(-1), and an energy density of 83.81 Wh kg(-1) at a current density of 1 A g(-1), with a storage capability of 1058.75 F g(-1). The combined effect of Ni and rGO doping in the composites resulted in a notable reduction in series and charge transfer resistances. Under optimal conditions, it exhibited excellent electrochemical performance, as indicated by good ionic conductivity (0.037 S cm(-1)), the highest transference number for cations (0.90), and a rate constant of 1.42 × 10(-8) cm s(-1) at an exchange current density of 0.00137 A g(-1), as well as a diffusion coefficient of 8.03 × 10(-13) m(2) s(-1), suggesting enhanced ion transport characteristics. These promising attributes of Zn(0.90)Ni(0.10)Se/rGO strongly demonstrate it as an ideal electrode material for advanced energy storage applications.