Facile Fabrication of Graphene/Mn3O4/Cu(OH)2 on Cu Foil as an Electrode for Supercapacitor Applications

Abstract

To improve the specific capacitance of graphene based supercapacitor, new ternary graphene/Mn₃O₄/Cu(OH)₂ composite was synthesized by two-step method. First, graphene/Mn₃O₄ composites with different weight ratio (G : Mn = 1 : 1, G : Mn = 1 : 4, G : Mn = 1 : 7 and G : Mn = 1 : 10) were synthesized by mixing and annealing method. Second, Cu(OH)₂ rods were deposited on Cu foil. Afterwards, graphene/Mn₃O₄ composite powders were deposited on Cu(OH)₂/Cu copper current collector as working electrodes. The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The XRD analysis revealed the presence of graphene/Mn₃O₄. The presence of Mn₃O₄ was also confirmed by Fourier transform infrared spectroscopy and Raman spectroscopy. Graphene/Mn₃O₄/Cu(OH)₂ composite electrode with the weight ratio of G : Mn = 1 : 7 showed the best electrochemical performance and exhibited the largest specific capacitance of approximately 266 F g2⁻¹ at the scan rate of 10 mV/s in 6 M KOH electrolyte. In addition, other electrochemical measurements (charge-discharge and EIS) of the G/Cu(OH)₂/Cu, and G/Mn₃O₄/Cu(OH)₂/Cu electrodes suggested that the G/Mn₃O₄/Cu(OH)₂/Cu electrode is promising materials for supercapacitor application.