Structural, morphological, and electrical properties of safe PEO electrolyte

Abstract

This work aims to fabricate and characterize polymer composites as electrolyte materials. Using the solution casting process, lithium chloride (LiCl) salt concentrations of 5, 8, 10, 12, and 15% wt/wt were dissolved in a solution of acetonitrile and polyethylene oxide to create Polyethylene Oxide (PEO) electrolyte. After that, the electrolytes produced are characterized to examine their properties. A tension test was used to investigate the mechanical properties, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to study the structural properties, and UV VIS and Fourier-transform infrared spectroscopy (FTIR) were used to study the optical properties. The DC and AC tests were used to examine the electrical properties. XRD results show the presence of two distinct Bragg peaks (120) and (112) at 19.15° and 23.35° respectively in the pure PEO XRD pattern suggesting that the polymer has a semicrystalline structure. From the XRD studies, the electrolyte's crystallinity has deteriorated as a result of the rising concentration of lithium chloride. According to the SEM data, the micrographs demonstrate the crystalline nature and amorphous boundaries of the polymer electrolytes. The PEO electrolytes' surfaces show extensive pore architectures and interconnected network topologies. The results of the tension test indicated that the young modulus was 1.95 MPa at 8% LiCl concentration, the optimal ultimate strength was 22.5 MPa at 8% LiCl concentration, and the optimum elongation was 667% likewise at 8% LiCl concentration. The polymer and lithium chloride demonstrated good complexing, according to the FTIR data. According to the UV-VIS test, an increase in lithium chloride concentration causes the band gap to shrink by 3.7 eV for 12% LiCl, which is subsequently exacerbated by an increase in salt concentration. When the ionic conductivity was examined under temperature changes between 40 ˚C and 65˚C for PEO, the highest conductivity was 2.99×10-5 S/cm at 40˚C using 15% LiCl concentration.