Homogeneous reduced graphene oxide supported NiO-MnO2 ternary hybrids for electrode material with improved capacitive performance

Abstract

In the present study we focus on the synthesis of homogeneous nickel oxide/manganese dioxide nanoparticles (NiO/MnO2 NPs) supported on reduced graphene oxide nanosheets (rGO NSs) for supercapacitors application. The homogeneous NiO-MnO2@rGO ternary hybrid was synthesized via simple, fast and facile approach using microwave irradiation process. The highly porous rGO NSs used to improve the performance of active electrode materials for high performance supercapacitors. In order to obtain high performance supercapacitors, there are several factors that must be achieved including a high porous surface area and high diffusion rate of the electrolyte inside active material. The structural and morphological studies of synthesized ternary hybrids material was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectra, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area. The extensive characterization shows that NiO/MnO2 NPs were homogeneously dispersed throughout the surface of rGO NSs. The pristine rGO NSs contains mesoporous structure with high surface area (570.45 m2/g) providing the supports of homogeneous dispersion of NiO/MnO2 NPs without aggregation. The mesoporous NiO-MnO2@rGO ternary hybrid exhibited a high specific capacity of 165.7 mAh/g with excellent long time cycling stability. The obtained result shows good specific capacity retention of 83.2% after 2000 continuous cyclic voltammetry and it shows no apparent decrease in the specific capacity after initial few cycles. It reveals that the NiO-MnO2@rGO ternary hybrids can be a promising electroactive material for supercapacitor applications.