| Supercapacitors, as a new type of energy storage device, due to its fast charge and discharge rate, high power density, long cycle life, simple maintenance, environment friendly and many other outstanding characteristics, have attracted of interests of the researchers worldwide. At present, how to further improve the specific capacitance and energy density is the key point in our research.Using the polystyrene (PS) spheres of uniform grain size as templates, we synthetized the polypyrrole (PPy) hollow spheres with a simple chemical method. By composing PPy hollow spheres with graphene, the rational designed graphene/hollow PPy3-D nanoarchitecture in which hollow PPy spheres were inserted between graphene layers can be obtained. The morphology and composition of the synthetized materials are characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Raman, Fourier transform infrared spectrum (FTIR) and thermogravimetric analysis (TGA).The as-prepared PPy hollow spheres and graphene/hollow PPy nanoarchitecture were explored as electrode materials for supercapacitor applications. Electrochemical performance of electrode materials was tested by means of Cyclic voltammogram (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). The results show that the specific capacitance has been greatly enhanced when the PPy spheres were hollowed. Furthermore, the specific capacitance doesn’t decline but gradually rise to as high as504.5F/g with a charging/discharging current density of5A/g, and eventually remains stable at about500F/g during10000cycles. Moreover, we discuss the mechanism of the rising of the specific capacitance of the electrode materials during the charge-discharge process, analysis indicates that during this process, more ion paths into the hollow PPy spheres were opened gradually, thus leading to a significantly enhanced electrochemical performance. |
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