Surfactant-Free Synthesis of Nb₂O₅ Nanoparticles Anchored Graphene Nanocomposites with Enhanced Electrochemical...

Nb₂O₅/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 Nb₂O₅ nanoparticles intercalated into the graphene sheet. The thermal stability of graphene oxide, Nb₂O₅, and Nb₂O₅/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 Nb₂O₅/graphene nanocomposites is greater (633 Fg^-1) than pure Nb₂O₅ nanoparticles (221 Fg^-1) and graphene (290 Fg^-1) at a current density of 1 Ag^-1. 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 Nb₂O₅/graphene nanocomposites have the potential to be an effective electrode for superior performance supercapacitor applications.