Tamarind seed polysaccharide biopolymer membrane for lithium-ion conducting battery

Abstract

Solid biopolymers have gained much attention in the development of polymer electrolytes due to its biocompatibility, film-forming nature, and non-toxicity. In the present work, biopolymer membrane has been prepared using tamarind seed polysaccharide (TSP) as host polymer and various concentrations of lithium chloride (LiCl) salt as dopant by solution casting technique. The prepared biopolymer electrolyte has been characterized by XRD, FTIR, differential scanning calorimetry (DSC) analysis, AC impedance spectroscopy analysis, and transference number measurement. XRD analysis has been done to investigate the amorphous/crystalline nature of the polymer membrane. The highest amorphous nature has been found for 1 g of TSP with 0.4 g LiCl. FTIR spectrum analysis confirms the complex formation between TSP biopolymer with LiCl. From AC impedance conductivity analysis, the maximum ionic conductivity is of the order of 6.7 × 10−3 S cm−1 at room temperature for 1 g TSP with 0.4 g LiCl, whereas for pure TSP biopolymer membrane, the ionic conductivity is of the order of 5.48 × 10−7 S cm−1. The glass transition temperature for the highest conducting biopolymer membrane for the composition of 1 g TSP: 0.4 g LiCl has been found to be 44.25 °C using the DSC technique. Employing the maximum conducting biopolymer membrane, a lithium-ion conducting battery has been fabricated and its discharge characteristics have been studied.