Electrical, electrochemical and structural studies of a chlorine-derived ionic liquid-based polymer gel electrolyte

In the present article, an ionic liquid-based polymer gel electrolyte was synthesized by using poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) as a host polymer. The electrolyte films were synthesized by using the solution casting technique. The as-prepared films were free-standing and transparent with good dimensional stability. Optimized electrolyte films exhibit a maximum room-temperature ionic conductivity of σ = 8.9 × 10−3 S·cm−1. The temperature dependence of the prepared polymer gel electrolytes follows the thermally activated behavior of the Vogel–Tammann–Fulcher equation. The total ionic transference number was ≈0.91 with a wider electrochemical potential window of 4.0 V for the prepared electrolyte film which contains 30 wt % of the ionic liquid. The optimized films have good potential to be used as electrolyte materials for energy storage applications.

Structural, Electrical and Electrochemical Properties of Glycerolized Biopolymers Based on Chitosan (CS): Methylcellulose (MC) for Energy Storage Application

In this work, a pair of biopolymer materials has been used to prepare high ion-conducting electrolytes for energy storage application (ESA). The chitosan:methylcellulose (CS:MC) blend was selected as a host for the ammonium thiocyanate NH4SCN dopant salt. Three different concentrations of glycerol was successfully incorporated as a plasticizer into the CS–MC–NH4SCN electrolyte system. The structural, electrical, and ion transport properties were investigated. The highest conductivity of 2.29 × 10−4 S cm−1 is recorded for the electrolyte incorporated 42 wt.% of plasticizer. The complexation and interaction of polymer electrolyte components are studied using the FTIR spectra. The deconvolution (DVN) of FTIR peaks as a sensitive method was used to calculate ion transport parameters. The percentage of free ions is found to influence the transport parameters of number density (n), ionic mobility (µ), and diffusion coefficient (D). All electrolytes in this work obey the non-Debye behavior. The highest conductivity electrolyte exhibits the dominancy of ions, where the ionic transference number, tion value of (0.976) is near to infinity with a voltage of breakdown of 2.11 V. The fabricated electrochemical double-layer capacitor (EDLC) achieves the highest specific capacitance, Cs of 98.08 F/g at 10 mV/s by using the cyclic voltammetry (CV) technique.

Tin Doped Barium Titanate (BaTiO3) Synthesized through Molten Salt Method as Promising Dielectric Material

Tin doped barium titanate (BaTiO3) was prepared through NaCl-KCl eutectic melt at 800 ºC. The synthesized materials were well characterized using powder-X-ray diffraction (PXRD) and FESEM-EDX spectroscopy. Cubic structure was observed in the PXRD pattern of tin doped sample. The crystallite size of tin doped barium titanate nanoparticles was found to be around 17 nm. Nanorods and aggregated nanocubes like structure were observed in the FESEM images and elemental ratio of doped ions was confirmed by energy dispersive X-ray spectrum (EDX). Electrical properties observed for the synthesized material were found better than those reported in the literature prepared by other methods. The dielectric constant and dielectric loss were measured in the temperature range of 100-400 K and the frequencies varying from 10 kHz to 10,000 kHz. The tin doped barium titanate showed rod type morphology with an unprecedented high dielectric constant of ~17,500 at 10 Hz. Dielectric constant values decreased with increasing frequency. The change in dielectric constant with frequency was well explained by Maxwell-Wanger polarization effect. The impedance and ionic transference number (tion) were also measured.

Hybrid Electrolytes with Ultrahigh Li-Ion Transference Number for Lithium-Metal Batteries with Fast and Stable Charge/Discharge Capability

Electrolytes with high ionic transference number hold great promise for reducing battery polarizations and achieving safe energy storage. Herein, single-ion electrolytes containing α-LiAlO2@γ-Al2O3 nanosheets as fillers in PVDF-HFP are prepared....

The Study of Structural, Impedance and Energy Storage Behavior of Plasticized PVA:MC Based Proton Conducting Polymer Blend Electrolytes

In this study, structural characterization, electrical properties and energy storage performance of plasticized polymer electrolytes based on polyvinyl alcohol/methylcellulose/ammonium thiocyanate (PVA/MC-NH4SCN) were carried out. An X-ray diffraction (XRD) study displayed that the plasticized electrolyte system with the uppermost value of direct current (DC) ionic conductivity was the most amorphous system. The electrolyte in the present work realized an ionic conductivity of 2.903 × 10−3 Scm−1 at room temperature. The main charge carrier in the electrolyte was found to be the ions with the ionic transference number (tion) of 0.912, compared to only 0.088 for the electronic transference number (telec). The electrochemical stability potential window of the electrolyte is 2.1 V. The specific capacitance was found to reduce from 102.88 F/g to 28.58 F/g as the scan rate increased in cyclic voltammetry (CV) analysis. The fabricated electrochemical double layer capacitor (EDLC) was stable up to 200 cycles with high efficiency. The specific capacitance obtained for the EDLC by using charge–discharge analysis was 132.7 F/g at the first cycle, which is slightly higher compared to the CV plot. The equivalent series resistance (ESR) increased from 58 to 171 Ω throughout the cycles, which indicates a good electrolyte/electrode contact. Ions in the electrolyte were considered to have almost the same amount of energy during the conduction process as the energy density is approximately at 14.0 Wh/kg throughout the 200 cycles. The power density is stabilized at the range of 1444.3 to 467.6 W/kg as the EDLC completed the cycles.

The Study of Plasticized Solid Polymer Blend Electrolytes Based on Natural Polymers and Their Application for Energy Storage EDLC Devices

In this work, plasticized magnesium ion-conducting polymer blend electrolytes based on chitosan:methylcellulose (CS:MC) were prepared using a solution cast technique. Magnesium acetate [Mg(CH3COO)2] was used as a source of the ions. Nickel metal-complex [Ni(II)-complex)] was employed to expand the amorphous phase. For the ions dissociation enhancement, glycerol plasticizer was also engaged. Incorporating 42 wt% of the glycerol into the electrolyte system has been shown to improve the conductivity to 1.02 × 10−4 S cm−1. X-ray diffraction (XRD) analysis showed that the electrolyte with the highest conductivity has a minimum crystallinity degree. The ionic transference number was estimated to be more than the electronic transference number. It is concluded that in CS:MC:Mg(CH3COO)2:Ni(II)-complex:glycerol, ions are the primary charge carriers. Results from linear sweep voltammetry (LSV) showed electrochemical stability to be 2.48 V. An electric double-layer capacitor (EDLC) based on activated carbon electrode and a prepared solid polymer electrolyte was constructed. The EDLC cell was then analyzed by cyclic voltammetry (CV) and galvanostatic charge–discharge methods. The CV test disclosed rectangular shapes with slight distortion, and there was no appearance of any redox currents on both anodic and cathodic parts, signifying a typical behavior of EDLC. The EDLC cell indicated a good cyclability of about (95%) for throughout of 200 cycles with a specific capacitance of 47.4 F/g.

Silicon Substituted Lithium Stannum Phosphate Ceramic Electrolytes: Structural, Electrical and Electrochemical Properties

Structural, electrical and electrochemical properties of silicon (Si) substituted NASICON-structured lithium stannum phosphate, Li1+ySn2P3-ySiyO12 with 0 < y < 1 that was prepared by the low-temperature water-based sol-gel method has been investigated. From the structural analysis, all samples in the system displayed rhombohedral symmetry. The total ionic conductivity, σt, and ionic mobility, µ was increased with the increase of silicon content, y. A high ionic conductivity value of 6.05 × 10-5 S cm-1 exhibited at y = 0.5 with a temperature of 500 °C. Linear sweep voltammetry analysis showed that the sample was electrochemically stable up to 5.1 V. Meanwhile, the ionic transference number value of the sample was 0.99, suggesting that the majority of mobile charge carriers were predominantly due to ions. Thus, from these results, it indicated that silicon substitution in LiSn2P3O12 ceramic electrolytes is significantly enhanced the electrical and electrochemical properties.

Conductivity Studies of Epoxidized PMMA Grafted Natural Rubber Doped Lithium Triflate Gel Polymer Electrolytes

A gel polymer electrolytes (GPEs) comprising of 62.3 mol% of epoxidized-30% poly(methyl methacrylate) grafted natural rubber (EMG30) as a polymer host, LiCF3SO3 as a dopant salt and ethylene carbonate (EC) as a plasticizer was prepared by solution-casting technique. The effect of plasticizer on the EMG30- LiCF3SO3 on the ionic conductivity is explained in terms of the plasticizer loading of the film. The temperature dependence of the conductivity of the polymer films obeys the Vogel-Tamman-Fulcher (VTF) relationship. The ionic transference number is calculated using Wagner’s polarization technique shows that the conducting species are predominantly due ions and hence showed the system is an ionic conductor. Surface morphological analysis showed the sample with the highest conductivity exhibited most homogenous in nature.

Thermal Analysis of 1-Ethyl-3-Methylimidazolium Trifluoromethanesulfonate Ionic Liquid to PEO-NaCF3SO3 Polymer Electrolyte

The objective of this study is to investigate the effect of ionic liquid to PEO-NaCF3SO3 solid polymer electrolyte. Sodium ion conducting polymer electrolyte films consisting of Polyethylene oxide (PEO) as a polymer host, Sodium trifluoromethanesulfonate (NaCF3SO3) as doping salt and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMiTF) as ionic liquid has been prepared by solution cast technique. Different amounts (5, 10, 15, 20, 25 and 30 wt. %) of EMiTF will be added to the optimized polymer-salt composition to develop PEO - NaCF3SO3 – EMiTF polymer electrolyte. Difference Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) indicated that the crystalline degree and the weight loss % of the electrolyte decrease with increasing the wt. % of the EMiTF respectively. The ionic transference number was found in the value of 0.95 which suggests that ions are the charge carriers.

Structural, Electrical and Electrochemical Properties of Mg0.55Si1.9Al0.1Fe0.1(PO4)3 Ceramic Electrolytes

This study was undertaken to investigate the structural, electrical and electrochemical properties of Fe3+ substituted Mg0.55Si1.9Al0.1(PO4)3 compound synthesized by water-based sol–gel technique. X-ray diffraction showed that the compound crystallized in monoclinic crystalline phase with a space group of P1 21/c1. The sample sintered at 850 ˚C exhibited the highest conductivity of 1.42 × 10-6 S cm-1 at 373 K since it contained the highest number of mobile ions. It also exhibited the highest value of ion mobility, μ of 1.13 × 10-11 cm2 V-1 s-1 at ambient temperature which was attributed to the optimum size of migration channel as indicated by its unit cell volume. Linear sweep voltammetry result showed that the Mg0.55Si1.9Al0.1Fe0.1(PO4)3 was electrochemically stable up to 3.0 V. Meanwhile, its ionic transference number of 0.99 suggested that the majority of the mobile charge carriers were mainly to ions, expected to be Mg2+ ions.