Structural, morphological, and electrochemical properties of GO/PVA, rGO/PVA, and rGO–Si/PVA hybrid nanocomposite films

Abstract In the current study, flexible nanocomposite films of polyvinyl alcohol (PVA) incorporating graphene oxide (GO), reduced graphene oxide (rGO), and Si-modified rGO (rGO-Si) were successfully synthesized using chemical methods. Graphene oxide was synthesized by a modified Hummers’ method and then reduced to rGO using hydrazine hydrate, while rGO-Si nanocomposites were synthesized by simultaneous reduction and Si incorporation. The structural, morphological, and electrochemical characteristics of the synthesized films were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and cyclic voltammetry (CV). SEM analysis showed a distinct morphological transformation from semi-crystalline aggregates in pristine PVA to sheet-like structures in GO/PVA, wrinkled morphologies in rGO/PVA, and granular surface topographies in rGO-Si/PVA. XRD results confirmed the semi-crystalline structure of PVA and the partial recovery of the sp² carbon framework in rGO-based composites. Williamson-Hall plots indicated that rGO/PVA had the largest crystallite size (≈ 9.5 nm) and highest microstrain (ε ≈ 0.038), indicating defect-mediated structural changes. Electrochemical tests confirmed that rGO-Si/PVA had the highest specific capacitance (≈ 42 F g⁻¹ at 0.01 V s⁻¹), while rGO/PVA showed better corrosion protection properties, as reflected by a higher corrosion potential and lower corrosion rate. In general, the addition of rGO and rGO-Si into the PVA matrix enhances electrochemical properties and barrier properties, which indicates the potential of these flexible nanocomposites for solid-state energy storage and protective coating applications.