Glycerol as a Multifunctional Modifier: Synergistic Enhancement of Electrical and Structural Properties in PEO:NaF Electrolytes

Abstract
This study examines the impact of glycerol on the structural and electrochemical properties of polyethylene oxide (PEO) doped with 9% sodium fluoride (NaF) to develop enhanced solid polymer electrolytes (SPEs). X-ray diffraction (XRD) analysis indicates a reduction in crystallinity as the glycerol content increases. At 0% glycerol, sharp XRD peaks correspond to high crystallinity, while at 32% glycerol, peak broadening and reduced intensity indicate an amorphous structure. Fourier transform infrared spectroscopy confirms interactions between PEO, NaF, and glycerol, with key changes in O–H, C–H, and C=O stretching vibrations, highlighting enhanced hydrogen bonding and salt complexation. Electrochemical impedance spectroscopy (EIS) reveals that increasing the glycerol content decreases bulk resistance (Rb) from 550 kΩ at 0% glycerol to 5.7 kΩ at 32% glycerol, while improving ionic conductivity (σdc) from 1.26 × 10^−8 S/cm to 1.35 × 10^−6\r\n S/cm, corresponding to an approximately 107-fold increase. Dielectric constant (ε′) measurements show higher polarization at low frequencies for the 32% glycerol sample. Dielectric loss (ε″) decreases with increasing frequency, with glycerol-doped samples demonstrating enhanced ionic mobility. While the conductivity remains below that of some other plasticized systems, the findings provide valuable insight into the effect of glycerol on NaF-based PEO electrolytes—a previously underexplored system. These modifications render the PEO-NaF-glycerol system a promising candidate for energy storage applications, including solid-state batteries and supercapacitors, and highlight the importance of optimizing glycerol concentration to improve electrochemical performance.

Author
Ibrahim Nazem

DOI
https://doi.org/10.1007/s11664-025-12031-1

Publisher

ISSN
03615235, 1543186X

Publish Date: