Eco-friendly biopolymer electrolyte, pectin with magnesium nitrate salt, for application in electrochemical devices

Abstract

Current research on electrochemical device application focuses on the usage of biopolymers like chitosan, pectin, agar-agar, cellulose acetate, and carrageenan as the electrolyte. The present work deals with the study of an eco-friendly biopolymer electrolyte pectin with magnesium nitrate salt Mg(NO3)2 prepared by solution casting technique. The prepared biopolymer electrolytes were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), AC impedance analysis, and linear sweep voltammetry (LSV). XRD analysis has been used to confirm the amorphous nature of the biopolymer pectin and magnesium nitrate salt. FTIR analysis has been used to confirm the complex formation between the polymer and the salt. DSC analysis has been used to find the glass transition temperature (Tg) of the prepared biopolymer electrolytes. AC impedance analysis has been used to study the electrical characterization of the prepared biopolymer electrolytes. The biopolymer electrolyte 50 M.wt% pectin:50 M.wt% Mg(NO3)2 has the highest ionic conductivity in the order of 10−4 S cm−1. The total ionic transference number of the highest conducting sample is 0.97 and the transference number of Mg2+ ion is 0.29. LSV has been used to find the electrochemical stability of the biopolymer electrolytes. The electrochemical stability of 50 M.wt% pectin:50 M.wt% Mg(NO3)2 is 3.8 V. This biopolymer electrolyte has been used to construct magnesium ion battery and the battery performance has been studied.