Synthesis and Characterization of V2O5/rGO Hybrid Nanowire Composites as Electrode Materials for Energy Storage Applications

Abstract

Vanadium pentoxide (V2O5), a promising recent candidate, has attracted significant attention as an electrode material for electrochemical energy storage devices. In this work, V2O5 nanowires (NWs) were synthesized using a simple and efficient hydrothermal method. A composite of reduced graphene oxide (rGO) doped with V2O5 (V2O5/rGO) was also prepared using the same approach. Density Functional Theory (DFT)-based calculations of the structural parameters for both V2O5 and the V2O5/rGO composite indicate negative ground state energies, confirming the thermodynamic stability of both systems. Furthermore, energy-volume (E-V) curve analysis reveals that the V2O5/rGO composite achieves a lower minimum energy compared to pristine V2O5, suggesting improved structural stability due to the incorporation of rGO. The structural and morphological characteristics of V2O5 NWs and V2O5/rGO were examined and compared using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Their electrochemical performance was evaluated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge (GCD) techniques. Cyclic voltammetry exhibited quasi-rectangular curves with distinct redox peaks for both V2O5 NWs and V2O5/rGO, confirming their pseudocapacitive nature. EIS results demonstrated that V2O5/rGO possesses enhanced conductivity compared to pure V2O5, attributed to the lower resistivity of the nanocomposite. At a scan rate of 10 mV/s, the specific capacitance of V2O5 NWs was measured to be 110.3 F/g, whereas the V2O5/rGO composite exhibited an enhanced specific capacitance of 216.5 F/g. Similarly, GCD measurements showed significantly improved charge/discharge time and specific capacitance for the V2O5/rGO composite compared to the pure V2O5 NWs electrode. The superior electrochemical performance of the V2O5/rGO composite can be attributed to the presence of rGO nanosheets, which offer a high surface area, short ion diffusion paths, and efficient electron transport pathways.