Magnesium ion conducting Tamarind gum-based bio polymer electrolytes for the fabrication of energy applications and its performance analysis

Abstract

Magnesium ion (Mg²⁺) conducting Solid Bio Polymer Electrolytes (SBPEs) are prepared by the Tamarind Gum (TG) with the ion source of Magnesium Chloride by solution casting technique. Using XRD and FTIR analyses, the dissociation and complexation of the salt with the polymer host are observed. By using the AC impedance analysis, the higher ionic conductivity calculated for the 1g TG with 0.5g of magnesium chloride added sample (5 TML) is 3.48 × 10^− 3 S/cm and the activation energy is 0.045eV. The glass transition temperature attained for 5 TML is 127⁰C. The complex dielectric permittivity and dielectric modulus spectra are discussed. The relaxation time (τ) attained by tangent analysis for 5TML is 7.94× 10^− 7s. From the transference number measurement, it is concluded that the conductivity is mostly due to the transfer of magnesium ions. Using the 5 TML sample, a symmetrical supercapacitor and a primary battery are fabricated. From the Cyclic Voltammetry (CV), a specific capacitance of 413.05 Fg^− 1 is obtained at the low scan rate of 15 mV/s. From GCD, power and energy density are calculated as 1499 W/kg and 100 Wh/kg respectively. The performance of the primary magnesium battery is observed and the Open Circuit Voltage (OCV) is found as 2.23V.