Synthesis and characterization of V2O5/rGO hybrid nanowire composites as electrode materials for energy storage applications

Vanadium pentoxide V ₂ O ₅ a more recent candidate has gained much attention as an electrode material in the field of electrochemical energy storage devices. This work presents V ₂ O ₅ nanowires (NWs), synthesized by using a simple and efficient hydrothermal method. The nanowires composite rGO doped V ₂ O ₅ (V ₂ O ₅ /rGO) was also prepared by hydrothermal method. The DFT-based structural parameters of V₂O₅ and the V₂O₅/rGO composite indicate negative ground state energies, confirming the thermodynamic stability of both systems. Furthermore, the energy–volume (E–V) curve analysis reveals that the V₂O₅/rGO composite attains a lower minimum energy compared to pristine V₂O₅, suggesting enhanced structural stability upon the incorporation of rGO. The structural analysis and morphology of both V ₂ O ₅ NWs and V ₂ O ₅ /rGO were investigated and compared using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), the electrochemical properties were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and GCD (Galvanostatic Charge-Discharge) techniques. The quasi-rectangular shape-like curves with redox peaks were obtained by the cyclic voltammetry (CV), exhibiting that both the samples V ₂ O ₅ (NWs) and V ₂ O ₅ /rGO have pseudo-capacitive nature. Electrochemical Impedance Spectroscopy (EIS) revealed that there is an enhanced conductivity of V ₂ O ₅ /rGO than pure V ₂ O ₅ due to the low resistivity of V ₂ O ₅ /rGO nanocomposites. The specific capacitance of V ₂ O ₅ NWs was found to be 110.3 F/g at 10mv/s scan rate whereas for compositeV ₂ O ₅ /rGO the enhanced specific capacitance was 216.5 F/g at 10 mV/s scan rate. Similarly, results obtained from GCD (galvanostatic charge-discharge) indicate that charge/discharge time, as well as the specific capacitance of composite (V ₂ O ₅ /rGO), is much more enhanced than pure V ₂ O ₅ NWs electrode. The enhanced characteristics of V ₂ O ₅ /rGO are because of rGO nanosheets as they provide short diffusion distance for ions of electrolyte, high surface area, and large transfer of electrons.