دانلود رایگان مقاله رشد پلی آنیلین نانوسیم در فوم گرافن ماکرو/مزوپور برای ابرخازنها

Abstract

Free-standing hierarchical macro/mesoporous flexible graphene foam have been constructed by rational intergration ofwell dispersed graphene oxide sheets and amino-modified polystyrene (PS) spheres through a facile “templating and embossing” technique. The three dimensional (3D) macro/mesoporous flexible graphene foam not only inherits the uniform porous structures of graphene foam, but also contains hierarchical macro/mesopores on the struts by sacrificing PS spheres and the activation of KOH, which could providing rapid pathways for ionic and electronic transport to high specific capacitance. Vertically polyaniline (PANI) nanowire arrays are then uniformly deposited onto the hierarchical macro/mesoporous graphene foam(fRGO-F/PANI) by a simple in situ polymerization, which show a high specific capacitance of 939 F g−1. Thanks to the synergistic function of 3D bicontinuous hierarchical porous structure of graphene foam and effective immobilization of PANI nanowires on the struts, the assembled symmetric supercapctior with fRGO-F/PANI as electrodes exhibits a maximum energy density and power density of 20.9Wh kg−1 and 103.2 kW kg−1, respectively. Moreover, it also displays an excellent cyclic stability with a 88.7% retention after 5000 cycles.

4. Conclusions

In summary, the synergistic effects of hierarchical macro/mesoporous structure and PANI nanowires deposited on the graphene foam has been clearly demonstrated with high specific capacitance and cyclic stability flexible supercapacitor by a facile in situ polymerization. The 3D fRGO-F inherits uniform and controllable porous structures, providing rapid pathways for ionic and electronic transport to high specific capacitance. In particular, fRGO-F/PANI7 prepared by deposition of vertically aligned PANI nanowires onto porous graphene foam showed a 6-fold higher specific capacitance than that of fRGO-F. The symmetric fRGO-F/PANI7 supercapacitor exhibited a maximum energy density and power density of 20.9Wh kg−1 and 103.2 kWkg−1, respectively. It also achieves an excellent cyclic stability with 88.7% retention capacitance after 5000 cycles, attributing to the synergistic function of 3D hierarchical porous structure and effective PANI immobilization. Therefore, the interconnected hierarchical macro/mesoporous flexible graphene and PANI foam supercapacitor is a great potential to improve the electrochemical performance of energy storage systems.