Facile Synthesis of Cu₂O/RGO/Ni(OH)₂ Nanocomposite and its Double Synergistic Effect on Supercapacitor Performance

ABSTRACT: A nanocomposite for supercapacitor electrode materials was designed and developed by integrating partially disabled Cu₂O (low specific capacity, but high cycling ability) and Ni(OH)₂ (low cyclability and high specific capacity) in the presence of reduced graphene oxide (RGO) nanosheets. Nanocomposite of Cu₂O/RGO/Ni(OH)₂ was directly grown on nickel foam (NF) through a facile one-pot hydrothermal process without any other reductant or oxidant, in which nickel foam acted as both a reductant of GO and Ni source, and a substrate for nanocomposite. The resultant Cu₂O/RGO/Ni(OH)₂ nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectrometer (XPS), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The electrochemical performance of the as-synthesized Cu₂O/RGO/Ni(OH)₂/NF electrodes were evaluated using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectrometry (EIS) in 6 mol L⁻¹ KOH aqueous solution. This Cu₂O/RGO/Ni(OH)₂ nanocomposite exhibits superior capacitive performance: high capability (3969.3 mF cm⁻² at 30 mA cm⁻², i.e., 923.1 F g⁻¹ at 7.0 A g⁻¹), excellent cycling stability (92.4% retention even after 4,000 cycles, for RGO/Ni(OH)₂/NF, 92.3% after 1,000 cycles), and good rate capacitance (50.3% capacity remaining at 200 mA cm⁻²)