Impedance, Electrical Equivalent Circuit (EEC) Modeling, Structural (FTIR and XRD), Dielectric, and Electric Modulus Study of MC-Based Ion-Conducting Solid Polymer Electrolytes

Balen K Faris; Ary A Hassan; Shujahadeen B Aziz; Mohamad A Brza; Aziz M Abdullah; Ari A Abdalrahman; Ola A Abu Ali; Dalia I Saleh

doi:10.3390/ma15010170

Impedance, Electrical Equivalent Circuit (EEC) Modeling, Structural (FTIR and XRD), Dielectric, and Electric Modulus Study of MC-Based Ion-Conducting Solid Polymer Electrolytes

Materials (Basel). 2021 Dec 27;15(1):170. doi: 10.3390/ma15010170.

Authors

Balen K Faris¹, Ary A Hassan¹, Shujahadeen B Aziz^{1

2}, Mohamad A Brza³, Aziz M Abdullah³, Ari A Abdalrahman¹, Ola A Abu Ali⁴, Dalia I Saleh⁴

Affiliations

¹ Hameed Majid Advanced Polymeric Materials Research Lab., Physics Department, College of Science, University of Sulaimani, Qlyasan Street, Kurdistan Regional Government, Sulaimani 46001, Iraq.
² Department of Civil Engineering, College of Engineering, Komar University of Science and Technology, Kurdistan Regional Government, Sulaimani 46001, Iraq.
³ Medical Physics Department, College of Medicals & Applied Science, Charmo University, Chamchamal 46023, Sulaimani, Iraq.
⁴ Department of Chemistry, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia.

Abstract

The polymer electrolyte system of methylcellulose (MC) doped with various sodium bromide (NaBr) salt concentrations is prepared in this study using the solution cast technique. FTIR and XRD were used to identify the structural changes in solid films. Sharp crystalline peaks appeared at the XRD pattern at 40 and 50 wt.% of NaBr salt. The electrical impedance spectroscopy (EIS) study illustrates that the loading of NaBr increases the electrolyte conductivity at room temperature. The DC conductivity of 6.71 × 10^-6 S/cm is obtained for the highest conducting electrolyte. The EIS data are fitted with the electrical equivalent circuit (EEC) to determine the impedance parameters of each film. The EEC modeling helps determine the circuit elements, which is decisive from the engineering perspective. The DC conductivity tendency is further established by dielectric analysis. The EIS spectra analysis shows a decrease in bulk resistance, demonstrating free ion carriers and conductivity boost. The dielectric property and relaxation time confirmed the non-Debye behavior of the electrolyte system. An incomplete semicircle further confirms this behavior model in the Argand plot. The distribution of relaxation times is related to the presence of conducting ions in an amorphous structure. Dielectric properties are improved with the addition of NaBr salt. A high value of a dielectric constant is seen at the low frequency region.

Keywords: EEC modeling; XRD and FTIR; dielectric study; electric modulus analysis; impedance study; methylcellulose polymer electrolyte; relaxation processes.