Impact of lithium triflate (LiCF3SO3) salt on tamarind seed polysaccharide-based natural solid polymer electrolyte for application in electrochemical device

Abstract

Biopolymers have gained enormous awareness in recent years as a result of white pollution, which could conquer the shortcomings of toxic synthetic polymers. The present investigation is being focused on synthesizing and characterizing natural solid polymer electrolytes comprising of tamarind seed polysaccharide as host polymer and lithium triflate (LiCF3SO3) salt as ionic dopant via cost-effective solution-casting technique. X-ray diffraction analysis validates the increase in the concentration of ionic salt enhancing the amorphous nature of the polymer electrolyte which in turn may increase the ionic conductivity of the polymer electrolyte. Vibrational analysis by Fourier transform infrared spectroscopy confirms the complexation and interaction between TSP host biopolymer and LiCF3SO3 salt. Thermal characterization by differential scanning calorimetry indicates the change in glass transition temperature (Tg) of the polymer electrolyte due to the incorporation of LiCF3SO3 salt. Polymer electrolyte composition of 1 g TSP: 0.45 g LiCF3SO3 possesses the optimum ionic conductivity value of the order of 10−4 S cm−1 observed by AC impedance spectroscopy analysis. Electrochemical properties of the optimum conducting biopolymer electrolyte have been characterized via linear sweep voltammetry technique, and the results reveal that the electrochemical stability window of the prepared biopolymer electrolyte is appreciable. Optimum ionic conducting polymer membrane (1 g TSP: 0.45 g LiCF3SO3) has been employed to fabricate lithium ion conducting battery, and its cell parameters have been measured and reported.