Based Preparation And Supercapacitor Performance O ₃ 2 Composite Electrodes Nitrogen-doped Graphene And Fe

In recent years, efficient electrical environment-friendly energy storage systems become more and more important for the global environment pollution and the depletion of fossil fuels. Among the various energy storage systems, supercapacitors are typical energy storage devices which are considered as promising candidates for effective energy storage because of their important features including high power density, long life expectancy, high efficiency and safety. The suitable choice of the materials for supercapacitor electrodes plays a crucial role in the supercapacitors’practical applications. Graphene, a single layer of two-dimensional carbon atoms, emerges as an excellent electrode material because of its high electrical conductivity, high surface area and chemical stability.In this paper, we combined the way of N-doping to graphene and the way of compounding with a-Fe2O3particles to foster strengths and circumvent weaknesses. We prepared N-doping graphene (NG) and NG/Fe2O3composites (NGFeCs) as electrode materials with excellent electrochemical properties for supercapacitor, respectively. Herein, we utilized a facile hydrothermal method to synthesize NG and NGFeCs as electrode materials with excellent electrochemical properties for supercapacitor, respectively. The structure and morphology of the samples were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectraand and X-ray photoelectron spectroscopy (XPS). The results indicated that Fe2O3particles with size about20-200nm were homogenously anchored on NG sheets. Electrochemical properties of the synthesized materials were characterized by cycle voltammetry (CV) and galvanostatic charge/discharge (GCD) techniques within a potential window between-1.1V and-0.1V (vs. SCE) in1M Na2SO4electrolyte. The as-prepared NG and NGFeCs showed a better electrochemical performance than rGO and GFeCs or Fe2O3. The specific capacitance of NG electrode is136.0F/g (102.8F/g for rGO electrode) at a current density of2A/g. The specific capacitance of NGFeCs electrode is260.1F/g (150.4F/g for GFeCs electrode and82.4F/g for Fe2O3) at a current density of2A/g. Additionally, over82.5%(214.6F/g) of the original capacitance is retained after1000cycles at a current density of2A/g (61.4%for GFeCs electrode). The electrochemical impedance spectroscopy (EIS) was measured in the frequency range of100kHz-10mHz at open circuit potential with an AC perturbation of5mV. The internal resistance and the charge-transfer resistance of NG and NGFeCs electrodes were both smaller than those of rGO and GFeCs electrodes, resprctively. The superior electrochemical performance can be ascribed to the good electronic conductivity and more active and nucleation sites introduced by the nitrogen-doping (especially by pyrrolic N-doping) and the compounding with a-Fe2O3.