Eco-friendly guar gum polymer electrolytes doped with lithium nitrate for energy storage devices
摘要
A natural guar gum-based solid polymer electrolyte is developed by dissolving Lithium Nitrate in the polymer medium using solution casting method. Free-standing membranes of guar gum with various concentrations of lithium nitrate are obtained. X-ray analysis reveals that the prepared sample is highly amorphous. Complexation of guar gum with salt is verified by FTIR analysis. The ionic conductivity is calculated through electrochemical impedance spectroscopy and the highest ionic conductivity of 1.07 × 10–3 Scm−1 is exhibited by the sample containing 1.2 g guar gum and 0.4 g of Lithium nitrate. TGA study is carried out to study the thermal stability of the polymer electrolytes. The dielectric spectra are utilised to determine the dielectric constant and loss, offering important insights into the polarisation characteristics of the electrolytes. The plot of ionic conductivity of the highest conducting electrolyte versus inverse temperature is of Arrhenius type. Through LSV studies, the electrochemical stability of the optimum ionic conducting sample is 3.2 V and the transference number measurement for the sample is found to be 0.96 indicating that majority of charge carriers are ions.