Study of dielectric and interfacial properties of functional biopolymer-based electrolyte with enhanced conductivity for energy storage application

This study investigates sodium (Na+) ion-conductive biopolymer blend electrolytes with glycerol as a plasticizer for energy storage. Through FTIR, impedance spectroscopy, transference number measurement (TNM), and linear sweep voltammetry (LSV), we identify an optimal film for electric double layer capacitor (EDLC) application. Glycerol induces notable changes in polymer-salt interaction, evidenced by FTIR band shifts reflecting increased free ions. Impedance measurements show reduced bulk resistance with optimal plasticizer content, emphasizing the system's suitability for energy storage. The system exhibits high real permittivity relative to imaginary at lower frequencies, attributing to glycerol's dielectric constant and small bulk resistance. Loss tangent (tanδ) and Argand plots reveal the dominant ion conduction mechanism. Electrochemical assessments support the suitability of the film for EDLC applications, featuring a favorable transference number (tion = 0.94) and high decomposition voltage (2.6V). Cyclic voltammetry (CV) curves demonstrate effective EDLC device design with significant capacitance adaptability across varying scan rates (5.946 F/g to 24.074 F/g). [Display omitted] •Developed eco-friendly reactive biopolymer blends of Chitosan:starch:NaI electrolytes via casting technique.•FTIR study confirmed co mplexation between electrolyte constituents.•EIS results showed improved conductivity with rising glycerol content reaching optimum value of 1.954×10−4 S cm−1.•Plasticized SPE has shown high potential stability of 2.6 V and good tion of 0.94.•The fabricated EDLC device has shown good specific capacitance of 24.07 F/g.