Study on graphene oxide modified by oligomers of <i>p</i>-phenylenediamine for supercapacitors

Abstract

In order to obtain high specific capacitance of the electrode used for supercapacitors based on new carbon materials,graphene oxide(GO),from graphite oxidized by chemicals,was modified by oligomers of p-phenylenediamine in an autoclave.The changes of molecular structure of p-phenylenediamine oligomers in ethanol solution under different heating processes were tested by UV-vis spectroscopy.The structure,morphology,electrical storage performance and cycle stability of the composite were characterized by X-ray diffraction,field emission scanning electron microscopy,and cyclic voltammetry.The results imply that oligomers of p-phenylenediamine can effectively expand the layer spacing of GO,and the composite shows a random stacking manner.Oligomers of p-phenylenediamine,heated at 60℃ for 48 h,have the greatest effect on the modification of GO.Specific capacitance of the composite is 453 F/g,and the retention is above 98% after 600 cycles.Furthermore,a prototype supercapacitor was fabricated in a CR2032 cell case.Calculated by the active substance,the energy density of the cell is 6.8 W·h/kg,and the power density is 516.3 W/kg.And the retention is 90% of its original charging/discharging process after 1000 cycles.The results imply that graphene oxide modified by oligomers of p-phenylenediamine will have a good potential application in energy storage.

Keywords

• <i>p</i>-phenylenediamine
• oligomers
• graphene oxide
• supercapacitors
• cycle performance