Dielectric and Thermal Properties of PEO/PVDF Blend Doped with Different Concentrations of Li 4 Ti 5 O 12 Nanoparticles
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Dielectric and Thermal Properties of PEO/PVDF Blend Doped with Different Concentrations of Li4Ti5O12 Nanoparticles R. S. Hafez1 · N. A. Hakeem2 · A. A. Ward3 · A. M. Ismail2 · F. H. Abd El‑kader1 Received: 18 March 2020 / Accepted: 20 June 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Poly (ethylene oxide) (PEO) and poly (vinylidene fluoride) (PVDF) films of compositions (50/50, 40/60, 30/70 and 20/80 wt/ wt%) are prepared by casting technique. X-ray diffraction (XRD), Differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) were studied for all samples. (20/80 wt/wt%) PEO/PVDF blend provides the proper blending of these polymers. (20/80 wt/wt%) PEO/PVDF blend doped with concentrations 0.5, 0.7, 1.0, 2.0, 5.0 and 7.0 wt% L i4Ti5O12 nanoparticles (NPs) were prepared using casting technique. The dielectric constant (ε′), dielectric loss (εʺ) and a.c conductivity (σac) as a function of frequency and temperature were studied for nanocomposite films. Thermal stability of the nanocomposite films was investigated using Thermogravimetric analysis (TGA). Adding of Li4Ti5O12 NPs to (20/80 wt/ wt%) PEO/PVDF enhances the electrical conductivity of the blend attributed to the charge carrier build up and increases in segmental mobility of polymeric chains. From TGA data, the calculated activation energies revealed that the thermal stability of (20/80 wt/wt%) PEO/PVDF improved with the addition of Li4Ti5O12 NPs. Keywords PEO/PVDF · Li4Ti5O12 NPs · FT-IR · AC conductivity · TGA
1 Introduction Modern technology now is directed to replacing the liquid electrolyte presented in lithium ion battery with a polymer membrane to be used as an electrolyte and as a separator. It helps for production batteries that all structure made of polymers further enhances systems safety [1]. Solid polymer electrolytes (SPEs) are used for enhancement battery design instead of liquid electrolytes because the problems that comes from decomposition of solvent such as leakage and gas formation [2]. High ionic conductivity of polymer electrolyte at ambient temperatures is one of the main requirements for use in lithium batteries, appreciable transference number, good mechanical strength, better compatibility with electrodes, thermal and electrochemical stability. * R. S. Hafez [email protected] 1
Physics Department, Faculty of Science, Cairo University, Giza 12613, Egypt
2
Physics Division, Spectroscopy Department, National Research Centre, Giza 12622, Egypt
3
Physics Division, Microwave Physics and Dielectrics Department, National Research Centre, Giza 12622, Egypt
Poly (ethylene oxide) (PEO) is the most favorable fundamental unit for polymer electrolytes. PEO chain would form a framework of helix coils in which lithium ions are stably solved [3]. The heteroatom (–O–) in PEO polymer chain has the facility to coordinate Li ions because it acts as electron donor. Lithium ions are coordinated mostly with the heteroatom on the same chain, also it can be coordinated with neighb
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