Optimizing and boosting the physicochemical properties of some polymer nanocomposites for high-performance and flexible energy storage systems

Copper oxide nanoparticles (CuO NPs) were synthesized using the co-precipitation technique. Solution casting techniques were used to successfully create nanocomposites made of sodium alginate (NaAlg) and polyvinyl pyrrolidone (PVP). These nanocomposites were doped with varying concentrations (1 %, 3 %, 7 %, 9 %, and 12 %) of copper oxide (CuO). The existence of the crystalline monoclinic phase in the CuO samples was confirmed through X-ray diffraction (XRD) analysis. XRD spectra of the PVP/NaAlg-CuO nanocomposite exhibited increasingly intense and sharp peak widths as the loading of CuO nanoparticles (NPs) increased. This observation indicates the crystalline nature of the nanocomposite, leading to higher ionic diffusivity and conductivity. The FTIR technique was used to study the chemical nature of the bonds found in the nanocomposite films. UV–visible spectroscopy was used to obtain the absorption, transmittance, and reflectance spectra of nanocomposite films. As the content of copper oxide increased, UV–Vis spectroscopy analysis revealed a reduction in the optical energy gap. The electrical conductivity of the electrolyte samples increased with more nanofiller loading, as seen by the electrical impedance spectroscopy (EIS) experiments carried out at room temperature. The dielectric properties analysis indicated higher values of space charge polarization, with an increase in the dielectric constant (εr) observed at lower frequency areas. The Nyquist diagram had a decreasing radius semicircular shape at low frequencies and a linear shape at high frequencies. This behavior suggests that the most appropriate fit could be achieved by using two equivalent circuit models. Based on the obtained results, it can be strongly inferred that the nanocomposite electrolyte samples exhibit significant potential as promising candidates for utilization in capacitors and flexible energy storage devices.