Synthesis, characterization, and multifunctional properties of Polyvinylpyrrolidone/Chitosan/Iron Molybdate nanocomposites for electrochemical devices

Abstract

This study examined the structure of the polymer matrix and the structural alterations caused by dispersing iron molybdate (FeMoO₄) nanoparticles to develop and characterize novel FeMoO₄-modified polyvinylpyrrolidone (PVP)/chitosan (CS) nanocomposites. The excellent physicochemical properties of polymer nanocomposite films, along with their ease of production and low cost, have made them a key focus in optoelectronics and energy storage research. XRD analysis revealed that the crystallinity of CS/PVP-FeMoO₄ nanocomposites decreased significantly with increasing nanoparticle concentration. FTIR analysis confirmed a strong interaction between the CS/PVP blend and FeMoO₄ nanoparticles. Optical properties were analyzed using a UV–Vis spectrophotometer. The direct and indirect band gaps of pure CS/PVP decreased from 4.53/4.01 eV to 3.51/2.92 eV in CS/PVP-2.6 wt% FeMoO₄. AC conductivity was studied via impedance spectroscopy at frequencies of 10²–10⁷ Hz and room temperature. Following Jonscher's rule, the AC electrical conductivity of the blend increased with FeMoO₄ content. The significantly enhanced conductivity of doped samples demonstrates that FeMoO₄ nanoparticle addition to the CS/PVP matrix improves charge conduction. Dielectric experiments revealed that CS/PVP/FeMoO₄ nanocomposites exhibit a low dielectric loss factor and high dielectric constant. Cyclic voltammetry (CV) was used to assess the sample's suitability for electrochemical double-layer capacitors (EDLCs). Overall, the enhanced electrical, dielectric, optical, and electrochemical performance of CS/PVP-FeMoO₄ nanocomposite films qualifies them for energy storage applications.