Preparation of Agarose-based Biopolymer Electrolytes Containing Calcium Thiocyanate: Electrical and Electrochemical Properties

• Published in: International journal of electrochemical science Vol. 17; no. 7; p. 220713
• Main Authors: Mohd Rafi, N.S., Abidin, S.Z.Z., Majid, S.R., Zakaria, R.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2022
• Subjects: agarose; Calcium Thiocyanate; dielectric; dielectric FTIR; impedance; LSV; XRD; CV; agarose; impedance; dielectric FTIR; XRD; Calcium Thiocyanate; dielectric; LSV
• ISSN: 1452-3981; 1452-3981
• DOI: 10.20964/2022.07.21

CaSCN─agarose biopolymer electrolytes were prepared by infusing various amounts of CaSCN salts (0–40 wt.%) in 0.5 g of agarose. CaSCN─agarose biopolymer electrolytes had been prepared through a solution casting technique and had been kept in the oven for 36 h at the temperature range of ~ 80 oC before the film form. The characterization technique included the electrical conductivity, structural and electrochemical properties of calcium-conducting biopolymer electrolytes in the frame of reference to match with universal needed for electrochemical devices in high energy storage appliances. The prepared electrolytes were characterized by electrical impedance spectroscopy (EIS) to study the electrical behaviour of the electrolytes at room temperature and temperature dependence. The highest conducting sample, 40 wt.% CaSCN─agarose biopolymer electrolytes resulted in a favourable ionic conductivity value of 8.01x10-05 S.cm-1, and all prepared samples of CaSCN─agarose biopolymer electrolytes obey Arrhenius behaviour. The ionic conduction mechanisms were presented in detail by dielectric studies and modulus studies. The molecular interactions between agarose polymer and CaSCN salts were further affirmed in fourier transform infrared spectroscopy (FTIR) studies and the results highlighted the presence of C─O─C, ─OH, ─CH, ─CC, ─NH and SCN anions. The maximum ionic conductivity value was successfully supported by X-Ray diffractometry (XRD), declared 40 wt.% CaSCN─agarose biopolymer electrolytes as the highest amorphicity due to the reduction of crystalline peaks at 2θ= 19 ͦ –22 ͦ and showed the lowest percentage of crystallinity, 31.81 % that calculated from deconvolution process. Electrochemical studies by linear sweep voltammetry (LSV) recorded that CaSCN─agarose biopolymer electrolytes resulted in a favourable electrochemical stability window at 2.9 V, and the result was supported by Cyclic Voltammetry (CV) analysis, and study paves in the fostering calcium conducting biopolymer electrolytes as a promising separator in calcium batteries.