Solid Polymer Electrolyte System Research Articles

Studies on Electrical Properties of Potassium Acetate Complexed with Polyvinyl Alcohol for Electrochemical Cell Applications

An attempt has been made in the present work to develop a new poly (vinyl alcohol) (PVA) based solid polymer electrolyte systems (PVA+ CH3COOK) in various compositions by solution cast technique. The structural parameters of pure PVA complexed with CH3COOK solid polymer electrolyte films were analyzed by X-ray diffraction (XRD) studies. The XRD structural properties reveal that as the salt concentration increases the amorphous domain regions in the PVA matrix increases. The structural vibration bonds between the polymer, dopant salt and its complexation was analyzed by Fourier transform infrared spectral studies. UV-visible studies revealed that the absorption peaks in ultraviolet region at (240-300nm) and is attributed due to polymer chain complex. The AC conductivity was measured at room temperature 303K was carried out .The ionic conductivity is increased by increasing the salt concentration in the polymer matrix. DC conductivity was measured in the temperature range of 303K–373K it reveals the conduction mechanism to be Arrhenius thermally activated process. The ionic conductivity of pure PVA was found to be at 9.63x10-9 S/cm at room temperature. Transference number is used to investigate the charge carries in these polymer electrolyte films by using Wagner's polarization technique. From the Transport number data it is confirmed that the charge transport in these polymer films was mainly due to ions. Using these polymer electrolytes, solid-state electrochemical cells were fabricated with the configuration of K+/(PVA+ CH3COOK)/(I2+C+electrolyte) and discharge characteristics were studied under the constant load of 100kΩ and the cell parameters like open-circuit voltage (OCV), short circuit current (SCC), energy density, and power density were determined.

CONDUCTIVITY AND DIELECTRIC STUDIES OF PURE AND DOPED POLY (ETHYLENE OXIDE) (PEO) SOLID POLYMER ELECTROLYTE FILMS

The solid polymer electrolytes (SPEs) composed of Poly (ethylene oxide) (PEO) with sodium trifluoromethanesulfonate (NaCF3SO3) salt has been prepared by solution casting technique. The conductivity and dielectric of the solid polymer electrolyte systems were studied within the broad frequency range of 50 Hz–1 MHz and within a temperature range of 30 ˚C to 100 ˚C. The samples were prepared by various salt concentrations ranging from 2 wt% to 22 wt%. The sample containing 18 wt% of NaCF3SO3 salt exhibit the highest ionic conductivity of 1.091 x 10-5 Scm-1 at 30 ˚C. The conductivity of the SPEs has been found to depend on the salt concentration that was added to the sample. When higher salt concentration was added, ionic conductivity decreased due to the association of ions. The temperature of conductivity from 30 ˚C to 100 ˚C of SPEs was found to obey the Arrhenius rule. The dielectric permittivity decreased rapidly towards high frequencies due to the electrode polarization effects.

Effect of Organic–Inorganic Hybrid Nanoparticles (POSS–PEG(n = 4)) on Thermal, Mechanical, and Electrical Properties of PEO‐Based Solid Polymer Electrolytes

ABSTRACTAdding organic–inorganic hybrid nanoparticles is a potential way to enhance room temperature ionic conductivity and mechanical strength of solid polymer electrolytes (SPEs). In this work, a new nanocomposite solid polymer electrolyte (NSPE) based on poly(ethylene oxide)–lithium bis(trifluoromethane sulfonyl) imide (PEO12–LiTFSI) incorporating polyhedral oligomeric silsesquioxane–poly(ethylene glycol) (POSS–PEG(n = 4)) hybrid nanoparticles has been prepared and reported the effect of POSS–PEG(n = 4) hybrid nanoparticles on thermal, mechanical, and electrical properties of (PEO12–LiTFSI) SPE. Results from X‐ray diffraction and differential scanning calorimetry studies indicated that the conductivity increase was due to the decrease in crystallinity upon the addition of lithium salt and POSS–PEG hybrid nanoparticles into the SPE system. The mechanical properties of PEO12–LiTFSI SPE tended to increase with the addition of POSS–PEG(n = 4) nanoparticles up to 10 wt% and decreased afterwards. The NSPEs having solid state show quite high ionic conductivity (1.45 × 10−4 S/cm at 30°C), which is about 7.44 times of magnitude larger than that of the matrix polymer (PEO12–LiTFSI) electrolyte (1.95 × 10−5 S/cm at 30°C).

Effect of lithium bis(trifluoromethylsulfonyl)imide salt-doped UV-cured glycidyl methacrylate

A study is carried out on solid polymer electrolytes (SPEs) based on UV-curable glycidyl methacrylate (GMA) reactive mixtures to determine the lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) effect at different weight percentages. These polymeric systems are discussed considering several factors such as chemical interaction, structural and thermal properties, ionic conductivity, and lithium transference number. Samples are prepared using solution casting technique and are analyzed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and electrochemical impedance spectroscopy (EIS) characterization methodologies. FTIR spectra show that interaction occurs between electronegative atoms in polymer host and TFSI− ions. XRD diffractogram indicates the amorphous aspect of SPEs, without the presence of LiTFSI peaks. Doping with LiTFSI salt reduces the glass transition temperature of SPEs and increased their ionic conductivity. Identified as the ideal salt concentration for poly(glycidyl methacrylate) (PGMA)-LiTFSI SPE system is 30 wt.% LiTFSI doping level, thus achieving a ionic conductivity of 3.69 × 10−8 S cm−1 at ambient temperature and 1.23 × 10−4 S cm−1 at 373 K. The ionic conductivity behavior obeys the Vogel–Tamman–Fulcher equation with an activation energy of 0.054 eV.

Effects of Nano Alumina and Plasticizers on Morphology, Ionic Conductivity, Thermal and Mechanical Properties of PEO-LiCF3SO3 Solid Polymer Electrolyte

In this contribution, a solid polymer electrolyte (SPE) was prepared by a ball milling method followed by a hot pressing process. The SPE used poly(ethylene oxide) (PEO) doped with trifluoromethanesulfonate (LiCF3SO3) as a host matrix. Nano alumina (Al2O3) was used as filler, and dioxyphthalate (DOP) and polyethylene glycol (PEG) applied as plasticizers. Various concentrations of lithium salts, nano alumina and plasticizers (5, 10, 15 and 20wt%) were studied. The morphology, ionic conductivity, thermal and mechanical properties of the SPE were also examined. The ionic conductivity increased from 10−7 to 10−6Scm−1 upon the addition of lithium salt. The PEO-15wt% (LiCF3SO3) solid polymer electrolyte exhibited maximum room temperature ionic conductivity. Significantly, the addition of nano alumina and plasticizers into PEO-LiCF3SO3 SPE enhanced the ionic conductivity to 10−5 and 10−4Scm−1, respectively. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies indicated that the conductivity increase was due to the decrease of crystallinity upon the addition of lithium salt, nano alumina and plasticizers into the SPE system. The mechanical properties of PEO tended to decrease with the addition of lithium salts, nano alumina and plasticizers. Nevertheless, durable film with high flexibility could be formed with a potential use as an efficient electrolyte in lithium and other rechargeable batteries.

Hydrogen ion conducting starch-chitosan blend based electrolyte for application in electrochemical devices

This paper reports the characterization of starch-chitosan blend based solid polymer electrolyte (SPE) system and its application in electrochemical double layer capacitor (EDLC) and proton batteries. All the SPEs are prepared via solution cast technique. Results from X-ray diffraction (XRD) verify the conductivity result from our previous work. Scanning electron microscopy (SEM) analysis shows the difference in the electrolyte's surface with respect to NH4Cl and glycerol content. From transference number measurements (TNM), transference number of ion (tion) of the electrolytes shows that ion is the dominant conducting species. Transference number of cation (t+) for the highest conducting electrolyte is found to be 0.56. Linear sweep voltammetry (LSV) result confirms the suitability of the highest conducting electrolyte to be used in the fabrication of EDLC and proton batteries. The EDLC has been characterized using cyclic voltammetry (CV) and galvanostatic charge-discharge measurements. The open circuit potential (OCP) of the primary proton batteries for 48h is lasted at (1.54±0.02)V, while that of secondary proton batteries is lasted at (1.58±0.01)V. The primary proton batteries have been discharged at different constant currents. The secondary proton battery has been charged and discharged for 40 cycles.

Conductivity and Dielectric Analysis of Cellulose Based Solid Polymer Electrolytes Doped with Ammonium Carbonate (NH<sub>4</sub>CO<sub>3</sub>)

The present work investigated the effect of carboxy methylcellulose (CMC) solid polymer electrolytes doped with ammonium carbonate (AC) prepared from solution cast technique. The CMC-AC solid polymer electrolytes system has been analyzed using EIS to understand its conductivity and dielectric behavior at temperature range of 303 K to 363 K. The highest conductivity achieved at room temperature (303K) is 7.71 x 10-6S cm-1doped with 7wt.% of AC and all samples follows Arrhenius behaviour. The dielectric constant (εr) value was found to be dependent of ionic dopant.

Investigations on the Effect of Chitin Nanofiber in PMMA Based Solid Polymer Electrolyte Systems

Polymer electrolyte membranes find application in a variety of fields such as battery systems, fuel cells, sensors and other electrochemical devices. In this paper we have done some investigations on the effect of chitin nanofiber (CNF) in PMMA based solid polymer electrolyte systems. CNF was synthesized from shrimp cell chitin by stepwise purification and acid hydrolysis method. PMMA basedelectrolyte films containing different concentrations of lithium salt and CNFs as filler were prepared by hot-press membrane technique. Crystalline nature and phase changes in polymer electrolytes were confirmed by X-ray diffraction analysis. Thermal behavior of the polymer electrolyte systems was studied by differential scanning calorimetry. Ionic conductivities of the electrolytes have been determined using a.c. impedance analysis in the temperature range between 303 and 393K. The temperature–dependent ionic conductivity

Plastic crystal–solid biopolymer electrolytes for rechargeable lithium batteries

In this paper, solid polymer electrolytes consisting of chitosan, lithium bis (trifluoromethylsulfonyl) imide (LiTFSI) as a salt and succinonitrile as a plastic crystal are prepared by using the solution casting method. Electrochemical impedance spectroscopy is used to examine the ionic conductivity of the films at the temperature range of 303–383K. Chitosan–LiTFSI containing 50wt% succinonitrile exhibits high ionic conductivity at a room temperature of 0.4×10−3Scm−1, a high lithium ion transference number (0.598) and wide electrochemical window. The solid polymer electrolyte with LiFePO4 as a cathode displays a stable discharge capacity of 160mAhg−1 for up to 50 cycles at a current density of 17mAg−1. The results demonstrate the potential for the solid polymer electrolyte system to be used as an electrolyte in lithium rechargeable batteries.

Lithium Conducting, Polar-Polar Polymer Blend Electrolytes with Systematically Varied Mechanical Properties and Ion Conductivity

Highly polar polymers such as PEO (polyethylene oxide)1-5 and PVDF (polyvinylidene difluoride)6-10 are well known as potential candidates for solid -state and gel-type electrolytes in rechargeable lithium-ion batteries, although the high crystallinity of these semi-crystalline, polar polymers leads to large polymer crystallites or crystalline domains which significantly lower their room-temperature ion conductivities.1-10 Hybrid polar-polar polymer blends, on the other hand, were previously reported to reduce the crystallinity of both polymer component, if a proper window of blend ratio is chosen. 11-13 This approach is more favored than an inert additive approach, in which inactive components that are not beneficial to ion transport are introduced to the electrolyte systems. Abraham, et al., reported the high ion conductivity of a polymer blend electrolyte made up with poly(vinylidene fluoride-co-hexafluoropropylene) or PVDF-HFP, oligomeric poly(ethylene glycol) dimethyl ether and lithium salts. In addition, Han, et al, studied ion transport of nanoparticle modified PEO/PVDF blends for dye-sensitized solar cell13. Several other reports examined ion transport behaviors in PEO/P(VDF-HFP)/lithium perchlorate (LiClO4) blend electrolytes.12 , 14 , 15 However, none of these reports provided a systematic and detailed nanostructure-ion transport correlation of polar-polar polymer hybrid electrolytes.Herein we studied PEO-PVDF- LiTFSI (lithium bis(trifluoromethanesulfonyl) imide) based hybrid electrolytes with systematically tunable mechanical properties and room temperature ion conductivities. We examined the nano- morphology dependent ion transport of these important type of composite electrolytes and their behaviors in solid polymer electrolyte systems. Based on results from a variety of experiments including nanoidentation, wide-angle X-ray diffraction, energy filtered TEM, and temperature-dependent impedance spectroscopy, we demonstrate that the low temperature ion conductivity of PEO/PVDF/LiTFSI blend can be 3 times higher than their parent electrolytes because of the largely optimized nanomorphology and mitigated polymer crystallinity. At the same time, we also show that, the modulus and hardenss of these blend electrolytes can be systematically tuned with the polymer blend ratio.(The attached energy filtered composite TEM images show oxygen, fluorine, and nitrogen distribution as a function of PVDFwt% in PEO/LiTFSi electrolytes.)1. Lascaud, S.; Perrier, M.; Vallee, A.; Besner, S.; Prudhomme, J.; Armand, M., Macromolecules 1994, 27, 7469-7477.2. Vallee, A.; Besner, S.; Prudhomme, J., Electrochimica Acta 1992, 37, 1579-1583.3. Gorecki, W.; Jeannin, M.; Belorizky, E.; Roux, C.; Armand, M., J. Physics-Condensed Matter 1995, 7, 6823-6832.4. Agrawal, R. C.; Pandey, G. P., J. Physics D-Applied Physics 2008, 41.5. Marzantowicz, M.; Dygas, J. R.; Krok, F.; Nowinski, J. L.; Tomaszewska, A.; Florjanczyk, Z.; Zygadlo-Monikowska, E., J. Power Sources 2006, 159, 420-430.6. Jiang, Z.; Carroll, B.; Abraham, K. M., Electrochimica Acta 1997, 42, 2667-2677.7. Kim, K. M.; Ryu, K. S.; Kang, S. G.; Chang, S. H.; Chung, I. J., Macromolecular Chem Phys 2001, 202, 866-872.8. Saikia, D.; Kumar, A., Electrochimica Acta 2004, 49, 2581-2589.9. Ramesh, S.; Lu, S.-C., J Molecular Structure 2011, 994, 403-409.10. Abbrent, S.; Plestil, J.; Hlavata, D.; Lindgren, J.; Tegenfeldt, J.; Wendsjo, A., Polymer 2001, 42, 1407-1416.11. Abraham, K. M.; Jiang, Z.; Carroll, B., Chem Mater 1997, 9, 1978-1988.12. Jacob, M. M. E.; Prabaharan, S. R. S.; Radhakrishna, S., Solid State Ionics 1997, 104, 267-276.13. Han, H. W.; Liu, W.; Zhang, J.; Zhao, X. Z., Adv Funct Mater 2005, 15, 1940-1944.14. Deka, M.; Kumar, A., Bulletin of Materials Science 2009, 32, 627-632.15. Fan, L. Z.; Dang, Z. M.; Nan, C. W.; Li, M., Electrochimica Acta 2002, 48, 205-209. Acknowledgements A portion of this research was conducted at the Center for Nanophase Materials Sciences, which is sponsored at Oak Ridge National Laboratory by the Division of Scientific User Facilities, Office of Basic Energy Sciences, U.S. Department of Energy.

The role of MgBr2 to enhance the ionic conductivity of PVA/PEDOT:PSS polymer composite

A solid polymer electrolyte system based on poly(vinyl alcohol) (PVA) and poly(3,4-Etylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) complexed with magnesium bromide (MgBr2) salt was prepared using solution cast technique. The ionic conductivity is observed to increase with increasing MgBr2 concentration. The maximum conductivity was found to be 9.89×10−6S/cm for optimum polymer composite film (30wt.% MgBr2) at room temperature. The increase in the conductivity is attributed to the increase in the number of ions as the salt concentration is increased. This has been proven by dielectric studies. The increase in conductivity is also attributable to the increase in the fraction of amorphous region in the electrolyte films as confirmed by their structural, thermal, electrical and optical properties.

Phase stability of Li-ion conductive, ternary solid polymer electrolytes

Abstract The chemical–physical properties of a ternary solid polymer electrolyte (SPE) system consisting of poly(ethylene oxide) and two salts, namely lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and the ionic liquid N-methyl-N-butyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14TFSI), are reported in this work. The ternary phase diagram shows the composition limits of the thermodynamically stabilized amorphous phase where the polymer electrolyte achieved the maximum conductivity. The important conductivity threshold of 10−3 S cm−1 at 40 °C is exceeded for these compositions. Two reasons for the high conductivity are identified; the decreased overall coordination to the Li+-ion and a Tg as low as −67 °C. Also presented is the thermal stability characterization of such polymer electrolytes. The amorphous phase seems to be thermodynamically unfavored; however, the recrystallization process is slow.

Plasticizing Effect of K+ Ions and Succinonitrile on Electrical Conductivity of [Poly(ethylene oxide)–Succinonitrile]/KI–I2 Redox-Couple Solid Polymer Electrolyte

The plasticizing effect of the K(+) ions and succinonitrile on the electrical conductivity of a new redox-couple solid polymer electrolyte system, (1 - x)[0.5poly(ethylene oxide):0.5succinonitrile]:x[0.9KI:0.1I2] with x = 0-0.2 in weight fraction, is reported. An increase of x resulted in an increase of the electrical conductivity (σ25°C) of the electrolyte. The electrolyte with x = 0.15 exhibited the highest σ25°C value, ~7 × 10(-4) S cm(-1), and is referred to as the optimum conducting composition (OCC). In addition to an increase of the mobile ion concentration with increasing x, X-ray diffractometry, Fourier-transform infrared spectroscopy, polarized optical microscopy, UV-vis spectroscopy, and differential scanning calorimetry studies revealed a decrease of poly(ethylene oxide) crystallinity/an increase of ionic mobility, indicating the plasticizing effect of the K(+) ions. Plasticizing and molecular diffusing properties of the succinonitrile further helped to improve the electrical conductivity of the electrolyte.

Characterization and application of the (PEO+KIO3+Plasticizer) solid state polymer electrolyte system

In the modern research domain, the study of polymer electrolytes is one of the extensively developing technologies for various applications. In this present study (PEO+KIO3+plasticizer), a specific approach is evaluated with respect to solid-state polymer electrolytes that were fabricated by using the solution casting method. The complexation of poly (ethylene oxide) (PEO), KIO3 and the plasticizer (dimethyle formamide [DMF]) have been investigated by using X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The transport properties of these polymer electrolytes are studied by using the d.c. conductivity. The conductivity — temperature plots are obtained in the range of 304–373 K. The plots have two regions, one below and the other the melting point (Tm). Also the conductivity of the polymer electrolytes is found to increase with increasing in temperature. Electrochemical cells are fabricated and the open circuit voltage (OCV) is found to be 2.85 V and the short circuit current (SCC) to be 356 µA. The discharge characteristics are examined at a constant load of 100 kΩ.

High performance composite solid polymer electrolyte systems for electrochemical cells

We report high performance composite solid polymer electrolytes for electrochemical cells with comprehensive properties in high mechanical strength and high ionic conductivity. The composite electrolytes consist of porous non-woven polymer filament substrates that are impregnated with high ion-conducting materials. To insure structural integrity, the non-woven polypropylene/polyethylene core–shell substrates are sulfonated to activate the surface. The high ion-conducting materials are prepared from poly(vinyl alcohol) with the incorporation of acrylic acid monomer and cross-linking agent. The results show well-balanced physical and electrochemical characteristics that warrant excellent battery discharge capacity and cell power density. The room temperature ionic conductivity is high at 0.16–0.21 S cm−1, and the activation energy is low at 0.5 kJ mol−1. The mechanical strength is improved to 12 MPa with good elongation at 58–62%. The anionic transport numbers (t−) are in the range of 0.93–0.99 in 1 M KOH, 0.91–0.97 in 1 M NaOH, and 0.83–0.91 in 1 M LiOH, respectively. The cyclic voltammetric study indicates good stability with symmetric curves between the cathodic and anodic peaks. The fully solid-state metal–air fuel cells exhibit excellent discharge capacity of 1506 mAh and high anode utilization of 95.7%. The power density is achieved at 91 mW cm−2.

Ionic Conductivity And Electrochemical Cell Studies Of New Mg2+ ion Conducting PVA/PEG Based Polymer Blend Electrolytes

Solid Polymer blend electrolytes based on Polyvinyl alcohol (PVA) and Polyethylene glycol (PEG) complex with Mg(CH3COO)2 at different weight percent ratios were prepared using solution cast technique. Conductivity in the temperature range 303-373 K and transference number measurements have been employed to investigate the charge transport in this solid polymer electrolyte system. The highest conductivity is found to be 3.23 x 10 -5 S/cm at 373K for sample with 30 weight percent of Mg(CH3COO)2 in PVA/PEG blend matrix. Transport number data shows that the charge transport in this polymer electrolyte system is predominantly due to ions. Using this electrolyte, an electrochemical cell with configuration Mg /(PVA+PEG+Mg(CH3COO)2)/ (I2+C+electrolyte) was fabricated and its discharge characteristics profile has been studied.

A simple P(VdF-HFP)–LiTf system yielding highly ionic conducting and thermally stable solid polymer electrolytes

In the present work, we report a simple solid polymer electrolyte (SPE) system that is solely based on poly(vinylidene fluoride-co-hexafluoropropylene) [P(VdF-HFP)] and lithium trifluoromethanesulfonate (LiTf). The SPEs produced exhibit high ionic conductivity of ~10−4Scm−1 at ambient temperature when 40wt.% of LiTf is incorporated. There is an anomaly when moderate amount of LiTf is added into the polymer. This can be related to formation of neutral ion pairs, and substantiated by calculation of activation energy and scanning electron micrographs. TGA thermograms also show that all the samples tested are thermally stable up to 400°C, even with the incorporation of LiTf. The highest ionic conducting sample achieves highest onset temperature of decomposition.

Towards magnesium ion conducting poly(vinylidenefluoride-hexafluoropropylene)-based solid polymer electrolytes with great prospects: Ionic conductivity and dielectric behaviours

A simple solid polymer electrolyte (SPE) system based purely on poly(vinylidenefluoride-hexafluoropropylene) [P(VdF-HFP)] and magnesium trifluoromethanesulfonate (MgTf) is synthesised via solution casting technique with acetone as solvent. The SPEs produced exhibit high ionic conductivity of ∼10−3S/cm at ambient temperature when 40wt.% of MgTf is incorporated. The major focus of this work is on ionic conductivity and dielectric behaviours. Three dissimilar types of impedance spectra have been identified and differentiated by magnitude of ionic conductivity. The trend of ionic conductivity increases almost proportionally to the content of magnesium salt and can be related to an increase of amorphous phase at high level of dopant salt. This SPE system has also been found to possess Arrhenius temperature dependence. This study discusses three samples with 10, 25 and 40wt.% of magnesium salt, representing low, intermediate and high concentrations of magnesium salt which are examined in frequency-dependence conductivity, dielectric permittivity and dielectric modulus studies.

Preparation and characterization of PVP-based polymer electrolytes for solid-state battery applications

Sodium ion conducting polymer electrolyte films based on poly(vinyl pyrrolidone) (PVP) were prepared using solution casting technique. Structural characterization was performed using X-ray diffraction (XRD) technique. Increase in amorphous phase with the increase of dopant concentration was observed. Temperature dependence of electrical conductivity was performed using AC impedance analyzing technique in the frequency range of 0.1 KHz to 1 MHz. Activation energy values were evaluated, as well. Optical absorption studies were carried out in the wavelength range 200–600 nm. Absorption edge, direct band gap, and indirect band gap values were also evaluated. Optical absorption edge and optical band gap (both direct and indirect) showed decreasing trend with increasing the concentration of the dopant. Dominant conducting species in the present electrolyte system was determined using Wagner polarization technique and dominant conducting species were found to be ions rather than electrons. Solid-state batteries were developed using the present solid polymer electrolyte system and discharge characteristics over the load of 100 kΩ. Cell parameters, e.g., open circuit voltage, short circuit current, current density, power density were evaluated, too. Among these cells, the cell made up of PVP/NaI (70/30) ratio for electrolyte was found to be more stable than the other two cells PVP/NaI (90/10) and (80/20) ratios and the obtained results were comparable with the results achieved by other studies.

Semi-interpenetrating polymer networks as solid polymer electrolytes: Effects of ion-dissociation, crosslink density and oligomeric entanglements on the conductivity behavior in poly(ethylene oxide)–polyurethane/poly(acrylonitrile) matrix

The present study investigates into three aspects of tailoring and simple structural modifications on a promising solid polymer electrolyte system of poly(ethylene oxide)–polyurethane/poly(acrylonitrile) semi-interpenetrating polymer networks. Influence of the nature of salt solvated, cation/anion mobility, ion–polymer interaction and transient crosslink formation is evaluated using different solvated electrolytes and the conductivity achieved varied as LiClO4≥LiCF3SO3>NaBF4>NaClO4>KI. The role of optimum chain length between the crosslinks (crosslink density) necessary to attain better conductivity levels is appraised using PEG of different molecular weights (400, 2000, 4000, 10,000 and 35,000) for synthesis and the maximum conductivity was obtained for PEG-4000. The temperature dependence of ion conductivity shows an Arrhenius to VTF transition at ∼323K in these semi-IPNs, a general behavior independent of the nature of salt and the poly(ethylene glycol) chain length. Ternary composition of semi-IPN containing 30wt% PEGDME MW 500 yields a conductivity of ∼2×10−5Scm−1 at 35°C, an order of magnitude higher than that obtained without plasticizing component. VTF behavior is witnessed throughout the temperature window in the study for samples with oligomeric plasticization. Linear sweep voltammetry indicates significantly good electrochemical stability (∼4.6V) of the semi-IPN electrolyte matrix.