Plasticized Polymer Electrolytes Research Articles

Conductivity and characterization of plasticized polymer electrolyte based on (polyacrylonitrile- b-polyethylene glycol) copolymer

A block copolymer polyacrylonitrile- b-polyethylene glycol was synthesized by the macroinitiator method. The copolymer mixed with a plasticizer—propylene carbonate (PC) and LiClO 4 to form plasticized polymer electrolytes. FT-IR spectra show that the lithium ion interacts with the groups that contain the un-bonded electrons. The results of FT-IR also indicate that the EO segment can improve the dissociation of lithium salt. The differential scanning calorimeter (DSC) used to study the thermal behaviors of different compositions. In this study, the conductivity increases with the content of PEG. Additionally, the plasticized polymer electrolyte based on the block copolymer has a good conductivity and can retain good mechanical strength.

Combined effect of Al 2O 3 nano-fillers and EC plasticizer on ionic conductivity enhancement in the solid polymer electrolyte (PEO) 9LiTf

Poly (ethylene oxide)—(PEO)-based composite polymer electrolytes are of great interest for solid-state-electrochemical devices. Among these materials, (PEO) 9LiCF 3SO 3 or (PEO) 9LiTf has been widely studied as a potential candidate. There have been many studies aimed at improving the ambient temperature ionic conductivity in this material either by incorporating plasticizers such as ethylene carbonate (EC) and propylene carbonate (PC) or by incorporating micro-sized or nano-sized inorganic fillers such as Al 2O 3, SiO 2 or TiO 2. However, to our knowledge, no report can be found in the literature on the combined effect of EC and Al 2O 3 on (PEO) 9LiTf. This paper describes the combined effect of incorporating the Al 2O 3 filler and the EC plasticizer on the ionic conductivity enhancement of the (PEO) 9LiTf electrolyte. Maximum conductivity enhancement has been achieved by optimizing the effects of the plasticizer and the ceramic filler. Nano-sized alumina filler-added, plasticized polymer electrolyte films (400–600 μm), prepared by common solvent casting method has been characterized by ionic conductivity and differential calorimetric measurements. The incorporation of 50 wt.% EC and 15 wt.% Al 2O 3 to the (PEO) 9LiTf electrolyte showed a significant conductivity enhancement with σ RT (max) = 1.5 × 10 − 4 S cm − 1 while retaining the mechanical strength of electrolyte films. As expected, the conductivity is enhanced by the plasticizer by reducing the crystallinity and increasing the amorphous phase content of the polymer electrolytes. The ceramic filler (Al 2O 3) also contributes to conductivity enhancement by promoting the above structural changes in the polymer electrolyte. It is evident that, an additional mechanism, directly associated with filler particles, would also be responsible for the conductivity enhancement caused by the filler. One possible explanation for this could be by creating additional sites for migrating ionic species through transient bonding with O/OH groups in the filler surface as suggested by previous workers. The decrease of T g values of plasticized and filler-added polymer electrolyte samples seen in the DSC thermograms points towards the improved segmental flexibility of polymer chains, leading to increased mobility of conducting ions.

Dye-sensitized solar cells based on TiO 2 nanotubes and a solid-state electrolyte

Anatase TiO 2 nanotubes were employed with success as photoanode in dye-sensitized solar cells (DSSC) using a plasticized polymer electrolyte based on a poly(ethylene oxide) derivative. The plasticized electrolyte, poly(ethylene oxide-co-epychlorohydrin) containing NaI–I 2 had their conductivity and thermal behavior characterized as a function of the salt content. The highest ionic conductivity (5.5 × 10 −4 S cm −1) was obtained with 12.5 wt% NaI and 50 wt% of the plasticizer poly(ethyleneglycol)dibenzoate. The TiO 2 nanotubes were prepared by a simple sol–gel route and were characterized by FEG-SEM, TEM, XRD and BET. For the same film thickness, the DSSC assembled with the titania nanotubes had much higher efficiency in comparison with the device using TiO 2 nanoparticles. Although the one-dimensional properties exhibited by these materials can improve the electronic transport, in this study we demonstrated that the increase in the DSSC performance may be much more closely related to the high surface area of the titania films. This more open structure allows much more dye to be chemically absorbed and also facilitates the penetration of the polymer electrolyte, improving the iodide diffusion inside the film. We also observed that it was necessary to introduce a film of nanoparticulated TiO 2 prior deposition of the nanotubes in order to improve electrical contact with the conducting glass. Devices with efficiency of 4.03% at 100 mW cm −2 (Xe(Hg) lamp) can be obtained using a combination of TiO 2 nanotubes and this plasticized polymer electrolyte.

Enhancing the ionic conductivity of PEO based plasticized composite polymer electrolyte by LaMnO 3 nanofiller

A new composite polymer electrolyte (CPE) based on polyethylene oxide (PEO) and LaMnO 3 as nano filler has been prepared by solution casting technique. SEM analysis clearly shows that the large spherulites in the crystalline domain of PEO disappear in the plasticized (PEO)–NaClO 4–LaMnO 3 composites and the surface morphology of SPE on plasticization becomes smoother. XRD and DSC data indicates that the amorphous nature of solid polymer electrolyte (SPE) increases with plasticizer concentration and is maximum for 30 wt% poly ethylene glycol (PEG). Impedance spectra of SPEs have also been made to provide an idea about the grain boundary resistance of the polymer electrolytes. Room temperature ionic conductivity of PEO–NaClO 4 increases substantially from 1.05 × 10 −6 to 5.30 × 10 −6 S cm −1 for PEO–NaClO 4–(10 wt%) LaMnO 3. It further increases with increasing PEG content in PEO–NaClO 4–(10 wt%) LaMnO 3 and attains a maximum value of 2.60 × 10 −4 S cm −1 for 30 wt% PEG based CPE. Arrhenius plot between log σ versus 1000/ T of CPE suggests that temperature dependent conductivity is a thermally activated process.

Crystallinity, thermal properties, morphology and conductivity of quaternary plasticized PEO‐based polymer electrolytes

AbstractQuaternary plasticized solid polymer electrolyte (SPE) films composed of poly(ethylene oxide), LiClO4, Li1.3Al0.3Ti1.7(PO4)3, and either ethylene carbonate or propylene carbonate as plasticizer (over a range of 10–40 wt%) were prepared by a solution‐cast technique. X‐ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) indicated that components such as LiClO4 and Li1.3Al0.3Ti1.7(PO4)3 and the plasticizers exerted important effects on the plasticized quaternary SPE systems. XRD analysis revealed the influence from each component on the crystalline phase. DSC results demonstrated the greater flexibility of the polymer chains, which favored ionic conduction. SEM examination revealed the smooth and homogeneous surface morphology of the plasticized polymer electrolyte films. EIS suggested that the temperature dependence of the films' ionic conductivity obeyed the Vogel–Tamman–Fulcher (VTF) relation, and that the segmental movement of the polymer chains was closely related to ionic conduction with increasing temperature. The pre‐exponential factor and pseudo activation energy both increased with increasing plasticizer content and were maximized at 40 wt% plasticizer content. The charge transport in all polymer electrolyte films was predominantly reliant on lithium ions. All transference numbers were less than 0.5. Copyright © 2006 Society of Chemical Industry

Ionic conductance of PDMAEMA/PEO polymeric electrolyte containing lithium salt mixed with plasticizer

Novel plasticized polymer electrolytes were synthesized with poly( N, N-dimethylamino-ethyl-methacrylate) (PDMAEMA), polyethylene oxide (PEO), LiTFSI as a salt, tetraethylene glycol dimethyl ether (tetraglyme), EC/PC and DEP as plasticizers. The ionic conductivity of various compositions of polymer electrolytes was investigated as a function of temperature, various concentrations of LiTFSI, plasticizers and various ratio of PDMAEMA/PEO. The ionic conductivity of PDMAEMA/PEO/LiTFSI (1.5 mol kg −1) with DEP as a plasticizer (1.5 × 10 −4 S cm −1) exhibited lower than PDMAEMA/PEO/LiTFSI (1.2 mol kg −1)/tetraglyme (5.24 × 10 −4 S cm −1) and PDMAEMA/PEO/LiTFSI (1.5 mol kg −1)/EC + PC (2.1 × 10 −4 S cm −1). As increasing the PDMAEMA concentration up to 13.3%, the ionic conductivity was decreased rapidly. As increasing the PDMAEMA concentration the ionic conductivity was decreased due to high viscosity and some interactions reducing ion pairing. These plasticized polymer electrolytes were characterized by impedance spectroscopy and DSC.

Impedance studies on plasticized PMMA-LiX [X: CF 3SO 3−, N(CF 3SO 2) 2−] polymer electrolytes

Plasticized polymer electrolytes composed of poly(methylmethacrylate) (PMMA) as the host, propylene carbonate (PC) or ethylene carbonate (EC) as a plasticizer and LiX (X: CF 3SO 3 − or N(CF 3SO 2) 2 −) as a salt were prepared by the solution cast technique. Impedance spectroscopy was performed in the temperature range between 303 and 383 K. In this paper, we report the electrical properties of polymer electrolytes with different lithium salts and plasticizers. The polymer electrolytes investigated exhibited high ionic conductivity at room temperature in the range of 10 − 6 to 10 − 4 S cm − 1 . The temperature dependence studies showed that the samples were ionic conductors and seemed to obey the Vogel–Tamman–Fulcher (VTF) rule. FTIR spectroscopy studies confirmed the polymer–salt interaction.

The conductivity and characterization of the plasticized polymer electrolyte based on the P(AN-co-GMA-IDA) copolymer with chelating group (II): The effect of free ion in the plasticized polymer electrolyte

A new gel-type polymer electrolyte (GPE) was made by the copolymerizing acrylonitrile (AN) and (2-methylacrylic acid 3-(bis-carboxymethylamino)-2-hydroxy-propyl ester) (GMA-IDA). The copolymer mixed with a plasticizer—propylene carbonate (PC) and lithium salt to form GPE. The lithium salts are LiCF 3SO 3, LiBr and LiClO 4. FT-IR spectra show that the lithium ion in the LiClO 4 system has the strongest interaction with the group based on the plasticized polymer. FT-IR spectra also indicate that CF 3SO 3 − prefers producing anion–cation association. Moreover, the 13C solid state NMR spectra for the carbons attached to the PC of GPE exhibited different level of chemical shift (158.5 ppm) when the different lithium salts were added to the electrolyte. The results of differential scanning calorimeter (DSC) also indicate that the LiClO 4 system has more free lithium ions; therefore, it has the maximum conductivity. In this study, the highest conductivity 2.98 × 10 −3 S cm −1 exists in AG2/PC = 20/80 wt.% system which contain 3 mmole (g-polymer) −1 LiClO 4. Additionally, the polymer electrolytes, which contain GMA-IDA have better interfacial resistance stability with lithium electrode.

A study on the blending effect of PVDF in the ionic transport mechanism of plasticized PVC–LiBF 4 polymer electrolyte

The hybrid plasticized polymer electrolyte composed of the blend of polyvinyl chloride (PVC) and poly vinylidene fluoride (PVdF) as a host polymer, the mixture of ethylene carbonate (EC) and propylene carbonate (PC) as a plasticizer and LiBF 4 as a salt was studied. An attempt was made to investigate the effect of PVdF in the plasticized PVC + LiBF 4 system in three blend ratios. The FTIR and DSC studies confirm the formation of polymer–salt complex and miscibility of the PVC and PVdF. The XRD results of plasticized PVC (S1, S2, S3) and PVdF blended (S4, S5, S6) were compared that increase in PVC concentration increases the degree of crystallinity (S1 < S2 < S3) and the blending of PVdF further increases the crystallinity (S4 < S5 < S5), which were confirmed in ionic conductivity measurements. The surface morphology of the films was also studied by Scanning Electron Microscope, which parallels the same.

Dual-phase polymer electrolyte with enhanced phase compatibility based on Poly(MMA-g-PVC)/PMMA

A new plasticized dual-phase polymer electrolyte (DPE) with enhanced phase compatibility based on Poly(MMA-g-PVC)/PMMA blends has been studied. For the DPE, PMMA is selectively impregnated with the lithium salt solution forming an ion-conducting network, while Poly(MMA-g-PVC) produces good mechanical strength. Their chemical characters, thermal behavior, morphology, ionic conductivity and interfacial compatibility with lithium metal electrode were characterized by using of infrared spectroscopy (IR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), optical microscopic images, alternating current impedance (AC impedance) and linear sweep voltammetry (LSV), respectively. The ionic conductivity of DPE increases with the ratio of PMMA/Poly(MMA-g-PVC) (by weight), and the absorbed liquid electrolyte in the polymer blends plays the first important way in this behavior. Room-temperature ionic conductivity of the order of 10 −3 S cm −1 has been achieved for DPE, in addition, the DPE also shows good compatibility with Li electrodes and sufficient electrochemical stability for safe operation in Li batteries.

Solid polymer electrolytes. XI. Preparation, characterization and ionic conductivity of new plasticized polymer electrolytes based on chemical‐covalent polyether–siloxane hybrids

AbstractA new hybrid polymer electrolyte system based on chemical‐covalent polyether and siloxane phases is designed and prepared via the sol–gel approach and epoxide crosslinking. FT‐IR, 13C solid‐state NMR, and thermal analysis (differential scanning calorimetry (DSC) and TGA) are used to characterize the structure of these hybrids. These hybrid films are immersed into the liquid electrolyte (1M LiClO4/propylene carbonate) to form plasticized polymer electrolytes. The effects of hybrid composition, liquid electrolyte content, and temperature on the ionic conductivity of hybrid electrolytes are investigated and discussed. DSC traces demonstrate the presence of two second‐order transitions for all the samples and show a significant change in the thermal events with the amount of absorbed LiClO4/PC content. TGA results indicate these hybrid networks with excellent thermal stability. The EDS‐0.5 sample with a 75 wt % liquid electrolyte exhibits the ionic conductivity of 5.3 × 10−3 S cm−1 at 95°C and 1.4 × 10−3 S cm−1 at 15°C, in which the film shows homogenous and good mechanical strength as well as good chemical stability. In the plot of ionic conductivity and composition for these hybrids containing 45 wt % liquid electrolyte, the conductivity shows a maximum value corresponding to the sample with the weight ratio of GPTMS/PEGDE of 0.1. These obtained results are correlated and used to interpret the ion conduction behavior within the hybrid networks. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1000–1007, 2006

Solid-state dye-sensitized solar cell: Improved performance and stability using a plasticized polymer electrolyte

The addition of the plasticizer poly(ethylene glycol)methyl ether to the polymer electrolyte based on poly(epichlorohydrin-co-ethylene oxide), NaI and I 2 increased the ionic conductivity by one order of magnitude (1.7 × 10 −4 S cm −1) without compromising its electrochemical, thermal and dimensional stabilities. The plasticized polymer electrolyte presented an estimated diffusion coefficient of 2 × 10 −6 cm −2 s −1, ca. five times higher than the diffusion coefficient estimated for the polymer electrolyte without plasticizer. Solid-state dye-sensitized TiO 2 solar cells (1 cm 2) were assembled with the plasticized polymer electrolyte and presented an open circuit potential of 0.64 V, short-circuit current of 0.60 mA cm −2 and an energy conversion efficiency of 1.75% under light intensity of 10 mW cm −2. This efficiency remained unchanged for 30 days, showing that cell efficiency and stability can be improved using a plasticized polymer electrolyte.

Effects of plasticiser on the lithium ionic conductivity of polymer electrolyte PVC-LiCF3SO3

Solid polymer electrolyte films based on poly(vinyl chloride)-lithium triflate (PVC-LiCF3SO3) have been prepared by the solution-cast technique in various concentrations. The film with the highest conductivity was used to prepare plasticised polymer electrolyte films by using poly(ethlene glycol) (PEG) of different molecular weights, i.e., 200, 400 and 600 gmol−1. These films were prepared to study the effects of addition of low molecular weights PEG on the lithium ionic conduction of the PVC based polymer electrolyte. The films were characterised by electrochemical impedance spectroscopy (EIS) and Fourier transform infrared-spectroscopy (FTIR). Results indicate that the molecular weight has an inverse effect on the conductivity and this has been accounted for by FTIR.

Stability of Lithium Polymer Battery Based on Substituted Spinel Cathode and PEG-Borate Ester∕PC Plasticized Polymer Electrolyte

The possible application of a novel plasticized polymer electrolyte in lithium battery based on substituted spinel cathode was investigated. The polymer electrolyte was prepared by dissolving in the host polymer, poly(ethylene glycol) methacrylates (PEGMs) plasticized by both propylene carbonate (PC) and poly(ethylene glycol)-borate ester (PEG-BE) of various compositions. The ionic conductivity σ of the polymer is enhanced with the addition of PC, while the lithium ion transference number reaches an optimum in a mixture of 49% PEG-BE and 21% of PC in the polymer weight. PEG-BE has been recognized to interact with anion as a Lewis acid, which leads to high lithium ion conductivity. The observed trend of σ and with decreasing PEG-BE is suggested as being due to enhancement of anion conductivity in the medium as a result of low viscous and high dielectric properties of PC coupled with suppressed Lewis acid interaction of PEG-BE. The cycle performance and the storage stability of the Li∕polymer electrolyte∕ cell comprising the above electrolyte were found to be quite acceptable for practical utility.

Effect of plasticizer on structure—property relationship in composite polymer electrolytes

A new plasticized composite polymer electrolyte (PCPE) based on poly(ethylene oxide)–NaClO 4 dispersed with a ceramic filler (SnO 2) and plasticized with polyethylene glycol (PEG 200) is reported. The effect of plasticizer concentration on changes in structure/microstructure and their correlation with physical properties has been investigated and reported. A substantial enhancement in the electrical conductivity, by two orders of magnitude at room temperature, of the PCPE has been noticed when compared with that of composite polymer electrolyte (CPE) films without any plasticizer. This enhancement in electrical conductivity of the PCPE films agrees well with the changes in the local microstructure/structure on plasticizer addition. Grain boundary resistance ( R gb) and glass transition temperature ( T g) have been observed to decrease with increasing concentration of PEG 200. Plasticizer addition has resulted in the suppression of crystallinity as observed from differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies. The DSC results indicate enhancement in the volume fraction of the amorphous phase, which appears to be consistent with the broadening in the polymer host peaks observed in X-ray diffractograms. The improvement in electrical conductivity has been achieved without any sharp deterioration in the thermal, electrochemical or mechanical stability of the PCPE thin films. These observations have been interpreted in terms of the action of plasticizer as a diluent/co-solvent.

Ionic conductivity studies of polymeric electrolytes containing lithium salt with plasticizer

New plasticized polymer electrolytes were synthesized based on poly ethylene oxide (PEO), Poly ( N, N-dimethylamino-ethyl-methacrylate) (PDMAEMA), LiN(CF 3SO 2) 2 (LITFSI) as the salt and tetraethylene glycol dimethyl ether(tetraglyme) and EC + PC as plasticizers. The preparation and characterization of the polymer electrolytes were investigated as a function of temperature and various concentrations of LITFSI. Impedance spectroscopy and differential scanning calorimeter (DSC) were used to characterize the effects of various temperature, lithium salt concentration and two plasticizers on conductivity. The complex of PDMAEMA/PEO/LiTFSI/tetraglyme (S2) exhibits higher conductivity (4.74 × 10 −4 S cm −1at 25 °C) than PDMAEMA/PEO/LiTFSI/EC + PC (S1).

Photoelectrochemical solar cells with polyacrylonitrile-based and polyethylene oxide-based polymer electrolytes

Two types of photolectrochemical (PEC) solar cells, FTO/TiO2/dye/PAN, EC, PC, Pr4N + I � ,I 2/Pt/FTO, and FTO/TiO2/dye/PEO, EC, PC, KI/I2/Pt/FTO have been fabricated using a PAN-based gel polymer electrolyte and a PEO-based plasticised polymer electrolyte. The PAN-based gel electrolyte, made of polyacrylonitrile (PAN), ethylene carbonate (EC), propylene carbonate (PC) and tetrapropylammoniumiodide (Pr4N + I � ) as the complexing salt exhibited a room temperature conductivity of 2.9 � 10 � 1 Sm � 1 for the composition, PAN (13%):EC (31%):PC (45%):Pr4N + I � (7%):I2 (4%) by weight ratio. The PEO-based polymer electrolyte had a conductivity of 2.2 � 10 � 3 Sc m � 1 for the composition PEO (37.5%):EC (37.5%):PC (20.7%):KI (3.9%):I2 (0.4%). These solar cells have been characterised using current–voltage characteristics and action spectra. The PAN-based solar cells had an overall quantum efficiency of 2.3%. However, the PEO-based solar cells had an overall quantum efficiency of only 0.6%. r 2004 Elsevier B.V. All rights reserved.

Methods for Optimizing Properties of Polymer Electrolytes Intended for Lithium Batteries

New plasticized polymer electrolytes, based on chlorinated derivatives of polyvinyl chloride, are studied by infrared and impedance spectroscopy. Morphological and electrochemical properties of the electrolytes depend on the nature of the lithium salt and liquid plasticizer and on the technology. Galvanostatic cycling data for lithium batteries based on Li-LiMn2O4 and Li-V6O13 and these electrolytes are presented.

Preparation and characterization of PVC/PMMA blend polymer electrolytes complexed with LiN(C2F5SO2)2

Thin films of polymer blend electrolytes comprising Poly(vinyl chloride) (PVC) and Poly(methyl methacrylate)(PMMA) and plasticized with a combination of ethylene carbonate (EC) and propylene carbonate (PC) for different lithium imide salt, LiN(C2F5SO3)2 , concentrations were prepared using the solution casting technique. The films were subjected to a. c. impedance measurements as a function of temperature ranging from -30 °C to 70 °C. The variation of ionic conductivity as a function of temperature and PVC content in the blend was analysed. The role of PMMA in the phenomena occurring at the interface between the plasticized polymer electrolyte and lithium electrode was also studied. The cast films were also subjected to TG/DTA and FT-IR studies which are discussed.

Li-ion conduction of plasticized PVA solid polymer electrolytes complexed with various lithium salts

Solid polymer electrolytes of high ionic conductivity are prepared using poly(vinyl alcohol) (PVA) complexed with various lithium salts such as LiClO 4, LiCF 3SO 3 and LiBF 4, and dimethyl phthalate (DMP) as plasticizer. The solid polymer electrolyte (SPE) films are characterized by X-ray diffraction, FTIR spectroscopy and ac impedance spectroscopic studies. Conductivity studies of these SPE films are carried out in the temperature range 302–373 K. The temperature dependence of the conductivity of polymer electrolyte films seems to obey VTF relation.