Preparation and characterization of polymer electrolyte based on biopolymer I-Carrageenan with magnesium nitrate

Abstract Biopolymer, a natural biodegradable polymer has attracted much attention in recent years. Global environmental awareness and fossil fuel depletion urged researchers to work in the biopolymer field. Some of the biopolymers used for the fabrication of rechargeable batteries are cellulose, chitosan, pectin, agar-agar and carrageenan. An alternative energy storage system and also equivalent to lithium ion battery technology is also a need today due to the environmental impact and safety limitations concerning lithium materials. To fulfill all these needs, in the present work, magnesium ion conducting polymer electrolyte for battery applications was synthesized using Iota carrageenan and magnesium nitrate salt. One-gram Iota Carrageenan is complexed with various concentrations of magnesium nitrate salt by solution casting technique. XRD technique confirms the amorphous nature of film. FTIR confirms the complex formation between polymer and salt. DSC study was carried out to analyze the glass transition temperature. AC impedance spectroscopy was used to study the conductivity and dielectric properties of polymer electrolyte. One-gram I-Carrageenan with 0.4 wt% of Mg(NO3)2 has shown a maximum ionic conductivity of 6.1 × 10−4S/cm and it possess lowest activation energy value of 0.175 eV. A Primary battery was constructed using maximum conducting polymer electrolyte and its performance was studied.