ZnO/CuO nanocomposite-based carboxymethyl cellulose/polyethylene oxide polymer electrolytes for energy storage applications

As a part of this investigation, polymer nanocomposite films were obtained by the casting method whereby polyethylene oxide (PEO) was mixed with carboxymethyl cellulose (CMC) at a 70:30 wt ratio (PEO/CMC) as a base before adding different concentrations (0.0, 0.3, 0.8, 2, 4, and 6 wt%) of ZnO/CuO nanocomposite (ZC NC) as a dopant, prepared by the sol-gel method. Subsequent analyses revealed that, compared with the pure mixture, the dielectric parameters and conductivity of the polymer nanocomposite (CMC/PEO-ZC NC) films markedly improved with the increase of ZC NC up to 2 wt%, while a decrement was noted for 4 and 6 wt%. Thus, the optimal concentration (CMC/PEO-ZC NC 2 wt%) was used in the subsequent investigations focusing on dielectric properties, and the temperature dependence of the dielectric parameters and conductivity. As ZC NC addition yielded beneficial outcomes, the structural and morphological changes caused by the doping process were successfully counteracted, as confirmed by the x-ray diffraction (XRD) and scanning electron microscopy (SEM) results. The calculated relaxation time (τ), activation energy (Ea), and improved dielectric properties suggest that these nanocomposite films are promising candidates for the development of solid-state supercapacitors.