Silver nanoparticle-enhanced PVA–PEO polymer electrolytes for energy storage and dielectric applications

Abstract

Poly(vinyl alcohol) (PVA)/polyethylene oxide (PEO) blend electrolytes incorporating silver nanoparticles (Ag NPs) were fabricated via a conventional solution-casting technique and systematically investigated for their structural, optical, electrical, and dielectric properties. Transmission electron microscopy confirmed that the synthesized Ag nanoparticles exhibit a nearly spherical morphology with a mean diameter of 29.87 nm. X-ray diffraction analysis revealed a progressive reduction in the crystallinity of PVA/PEO blend matrix with increasing Ag nanoparticles content, indicating enhanced amorphous character and strong polymer–nanoparticle interactions. Fourier-transform infrared spectroscopy confirmed interactions between Ag nanoparticles and the hydroxyl and ether functional groups of the blend. UV–visible optical studies demonstrated a concentration-dependent red shift in the absorption edge and a significant reduction in both indirect and direct optical band gap energies, decreasing from 4.99 and 5.30 eV for the pristine PVA/PEO blend to 4.15 and 4.56 eV, respectively, at higher Ag loadings. Electrical and impedance spectroscopy revealed a pronounced enhancement in ionic conductivity upon Ag incorporation, attributed to reduced bulk resistance, increased segmental mobility, and the formation of conductive pathways within the nanocomposite matrix. Furthermore, dielectric analysis showed high dielectric constants at low frequencies governed by Maxwell–Wagner–Sillars interfacial polarization. The combined improvements in structural, optical, electrical and dielectric properties highlight the potential of PVA–PEO/Ag nanocomposite electrolytes for energy storage applications, particularly high-performance dielectric capacitors and multifunctional polymer systems.