Structural, Impedance and Electrochemical Characteristics of Electrical Double Layer Capacitor Devices Based on Chitosan: Dextran Biopolymer Blend Electrolytes

Shujahadeen B Aziz; Muhamad H Hamsan; Muaffaq M Nofal; Wrya O Karim; Iver Brevik; Mohamad A Brza; Rebar T Abdulwahid; Shakhawan Al-Zangana; Mohd F Z Kadir

doi:10.3390/polym12061411

Structural, Impedance and Electrochemical Characteristics of Electrical Double Layer Capacitor Devices Based on Chitosan: Dextran Biopolymer Blend Electrolytes

Polymers (Basel). 2020 Jun 24;12(6):1411. doi: 10.3390/polym12061411.

Authors

Shujahadeen B Aziz^{1

2}, Muhamad H Hamsan³, Muaffaq M Nofal⁴, Wrya O Karim⁵, Iver Brevik⁶, Mohamad A Brza^{1

7}, Rebar T Abdulwahid^{1

8}, Shakhawan Al-Zangana⁹, Mohd F Z Kadir¹⁰

Affiliations

¹ Advanced Polymeric Materials Research Lab., Department of Physics, College of Science, University of Sulaimani, Qlyasan Street, Sulaimani 46001, Kurdistan Regional Government, Iraq.
² Department of Civil Engineering, College of Engineering, Komar University of Science and Technology, Sulaimani 46001, Kurdistan Regional Government, Iraq.
³ Institute for Advanced Studies, University of Malaya, Kuala Lumpur 50603, Malaysia.
⁴ Department of Mathematics and General Sciences, Prince Sultan University, P.O. Box 66833, Riyadh 11586, Saudi Arabia.
⁵ Department of Chemistry, College of Education, University of Sulaimani, Old Campus, Sulaimani 46001, Kurdistan Regional Government, Iraq.
⁶ Department of Energy and Process Engineering, Norwegian University of Science and Technology, N-7491 Trondheim, Norway.
⁷ Manufacturing and Materials Engineering Department, Faculty of Engineering, International Islamic University of Malaysia, Kuala Lumpur 50603, Gombak, Malaysia.
⁸ Department of Physics, College of Education, University of Sulaimani, Old Campus, Sulaimani 46001, Kurdistan Regional Government, Iraq.
⁹ Department of Physics, College of Education, University of Garmian, Kalar 46021, Iraq.
¹⁰ Centre for Foundation Studies in Science, University of Malaya, Kuala Lumpur 50603, Malaysia.

Abstract

This report presents the preparation and characterizations of solid biopolymer blend electrolyte films of chitosan as cationic polysaccharide and anionic dextran (CS: Dextran) doped with ammonium iodide (NH₄I) to be utilized as electrolyte and electrode separator in electrical double-layer capacitor (EDLC) devices. FTIR and XRD techniques were used to study the structural behavior of the films. From the FTIR band analysis, shifting and broadening of the bands were observed with increasing salt concentration. The XRD analysis indicates amorphousness of the blended electrolyte samples whereby the peaks underwent broadening. The analysis of the impedance spectra emphasized that incorporation of 40 wt.% of NH₄I salt into polymer electrolyte exhibited a relatively high conductivity (5.16 × 10^-3 S/cm). The transference number measurement (TNM) confirmed that ion (t_ion = 0.928) is the main charge carriers in the conduction process. The linear sweep voltammetry (LSV) revealed the extent of durability of the relatively high conducting film which was 1.8 V. The mechanism of charge storage within the fabricated EDLC has been explained to be fully capacitive behavior with no redox peaks appearance in the cyclic voltammogram (CV). From this findings, four important parameters of the EDLC; specific capacitance, equivalent series resistance, energy density and power density were calculated as 67.5 F/g, 160 ohm, 7.59 Wh/kg and 520.8 W/kg, respectively.

Keywords: EDLC study; XRD and FTIR study; biopolymer blend electrolyte; impedance.