Facile and scalable fabrication of graphene/polypyrrole/MnOx/Cu(OH)(2) composite for high-performance supercapacitors

In this study, to improve the specific capacitance of graphene-based supercapacitor, novel quadri composite of G/PPy/MnOx/Cu(OH)(2) was synthesized by using a facile and inexpensive route. First, a two-step method consisting of thermal decomposition and in situ oxidative polymerization was employed to fabricate graphene/polypyrrole/manganese oxide composites. Second, Cu(OH)(2) nanowires were deposited on Cu foil. Afterwards, for the electrochemical measurements, composite powders were deposited on Cu(OH)(2)/Cu foil substrate as working electrodes. The synthesized samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FT-IR) spectroscopy, and Raman spectroscopy. The XRD analysis revealed the formation of PPy/graphene, Mn3O4/graphene, and graphene/polypyrrole/MnOx. In addition, the presence of polypyrrole and manganese oxides was confirmed using FT-IR and Raman spectroscopies. Graphene/polypyrrole/MnOx/Cu(OH)(2) electrode showed the best electrochemical performance and exhibited the largest specific capacitance of approximately 370 F/g at the scan rate of 10 mV/s in 6 M KOH electrolyte. In addition, other electrochemical measurements (charge-discharge, EIS and cyclical performance) of the G/Cu(OH)(2), G/PPy/Cu(OH)(2), G/Mn3O4/Cu(OH)(2), and G/PPy/MnOx/Cu(OH)(2) electrodes suggested that the G/PPy/MnOx/Cu(OH)(2) composite electrode is promising materials for supercapacitor application.