Surfactant-Free Synthesis of NbO Nanoparticles Anchored Graphene Nanocomposites with Enhanced Electrochemical Performance for Supercapacitor Electrodes

NbO/graphene nanocomposites without any surfactant are synthesized by an in situ microwave irradiation technique. Structural and morphological studies revealed that the prepared composites were composed of NbO nanoparticles intercalated into the graphene sheet. The thermal stability of graphene oxide, NbO, and NbO/graphene nanocomposite was studied by the TGA. The electrochemical properties are assessed by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy analyses. The specific capacitance of NbO/graphene nanocomposites is greater (633 Fg) than pure NbO nanoparticles (221 Fg) and graphene (290 Fg) at a current density of 1 Ag. The long-term cyclic measurement confirms higher cyclic stability of the nanocomposite with capacitance retention of 99.3% after 5000 cycles without performance degradation. The composites exhibit higher electrochemical conductivity and allow effective ions and charge transport over the entire electrode surface with aqueous electrolyte. The electrochemical study suggests that NbO/graphene nanocomposites have the potential to be an effective electrode for superior performance supercapacitor applications.