Structural and electrical properties of TSP: CH3COONa amorphous Biopolymer electrolytes for electrochemical cell applications

Abstract

Solid biopolymer electrolytes have gained enormous attention recently due to their potential as non-toxic, biodegradable properties over their synthetic counterpart. Considering their uses in energy applications, the present investigation aims to synthesize and characterize solid biopolymer electrolytes comprising tamarind seed polysaccharide (TSP) as the host polymer and sodium acetate (CH3COONa) salt as the ionic dopant. The solution cast technique was employed to create free-standing tamarind seed polysaccharide (TSP): Sodium acetate (CH3COONa) solid polymer electrolyte films with varying weight percentages. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) studies investigated the structural and chemical correlation between TSP and CH3COONa. AC impedance spectroscopy was used to test the conductivity and dielectric properties of the prepared polymer films. The conductivity rises with increasing temperature. The maximum conductivity was found to be 1.95 × 10−4 S cm−1 for 80:20 (TSP: CH3COONa) wt.% ratio sample at room temperature (303 K), which was three orders of magnitude higher than the pure TSP (10−7 S cm−1). These polymer electrolyte films showed conductivity that altered with temperature, which follows Arrhenius's behaviour. Dielectric studies showed that dielectric constant and dielectric loss were high at low frequencies and decreased at high frequencies. Wagner's polarisation technique confirmed that charge transport in these polymer electrolyte systems was principally ionic, with the highest tion ( ̴ 0.99) and electrons having a negligible contribution. The discharge studies of the cell showed good stability and performance with OCV at 1.68 V and SCC at 0.69 mA.