Investigations on Structural, Optical Properties, Electrical Properties and Electrochemical Stability Window of the...

The incorporation of reduced Graphene oxides (rGO) as a nanofiller in the blend polymer nanocomposite (BPNC) based on Polyvinylpyrrolidone (PVP)-Polyvinylalcohol (PVA) and sodium bicarbonate (NaHCO₃) are presented. The blend polymer electrolytes films are prepared by the standard solution cast technique, and it is characterized to investigate the structural, morphological, thermal, optical and electrochemical property. The X-ray diffraction confirms the formation of polymer nanocomposite and is agreed with FESEM analysis. The FTIR confirms the presence of various interactions between the polymer, salt and rGO, and indicates the composite formation. The DSC examines the thermal property of the blend polymer nanocomposite electrolytes system. The bandgap energy has been obtained from the UV-spectroscopy and examines the direct and indirect gap, both offer the decreases bandgap with the addition of a higher concentration of rGO as nanofillers. The highest value of ionic conductivity of the film is obtained ~1.39×10^-6 S cm^-1 at 15 wt.% of rGO content in polymer blend nanocomposite (BPNC) films. For these BPNC films, the electrochemical stability window (ESW) is ~4.0 V at 25 wt.% of rGO content and ionic transport number (t_ion) is ~0.98, for 10 wt.% of rGO content at the room temperature. These highly stable blend polymer nanocomposite electrolyte films offer the excellent properties for utilized as a separator for solid-state devices e.g., battery, supercapacitors, electrochromic display devices and other electrochemical energy storage/ conversion devices respectively.