Solid Polymer Electrolyte Films Research Articles

Structural, conductivity, and dielectric characterization of PEO–PEG blend composite polymer electrolyte dispersed with TiO2 nanoparticles

A solid polymer electrolyte (SPE) composites consisting blend of poly(ethylene oxide) (PEO) and poly(ethylene glycol) (PEG) as the polymer host with LiCF3SO3 as a Li+ cation salt and TiO2 nanoparticle which acts as a filler were prepared using solution-casting technique. The SPE films were characterized by X-ray diffraction and Fourier transform infrared analysis to ensure complexation of the polymer composites. Frequency-dependent impedance spectroscopy observation was used to determine ionic conductivity and dielectric parameters. Ionic conductivity was found to vary with increasing salt and filler particle concentrations in the polymer blend complexes. The optimum ambient temperature conductivity achieved was 2.66 × 10−4 S cm−1 for PEO (65 %), PEG (15 %), LiCF3SO3 (15 %), ethylene carbonate (5 %), and TiO2 (3 %) using weight percentage. The dielectric relaxation time obtained from a loss tangent plot is fairly consistent with the conductivity studies. Both Arrhenius and VTF behaviors of all the composites confirm that the conductivity mechanism of the solid polymer electrolyte is thermally activated.

Ionic Conductivity and Dielectric Properties of Plasticized Polyacrylonitrile Based Solid Polymer Electrolyte Films

The conducting polymer electrolyte films composed of polyacrylonitrile (PAN) as the host polymer, LiCF3SO3 and NaCF3SO3 as inorganic salts and ethylene carbonate (EC) as plasticizer were prepared by the solution cast technique. The conductivities of the films were characterized by impedance spectroscopy. On addition of more than 14 wt% of salt, the NaCF3SO3-containing PAN films exhibited higher ionic conductivity than the LiCF3SO3-containing PAN films. The values of the dielectric constant, εr and dielectric loss, εi increase as frequency decreases at room temperature. The temperature dependence of the conductivity obeys Arrhenius relation in the temperature range of 303 K to 353 K.

Time response properties on deformation velocity for a solid polymer electrolyte sensor

This paper aims to clarify time response properties of a solid polymer electrolyte (SPE) sensor. SPE film has been attracted attention in wide range of fields, and it is expected to be used as soft actuators and sensors. SPE film can reversely convert electrical energy into mechanical energy. Moreover, SPE film is lightweight, flexible, and has good workability and air-stable output. Although authors have been investigated output characteristics of an SPE sensor, time response properties of the sensor have not been inspected. In the paper, to reveal time response properties of the SPE sensor, the sensor output behaviors for several deformation velocities are measured and evaluated. Maximum voltages in the transient response and output attenuations for constant deformation are analyzed. Results show that the attenuation characteristics depend on the sensor deformation velocity, and maximum voltages in the transient response are independent of deformation velocities.

Flexible resistive switching memory using inkjet printing of a solid polymer electrolyte

Resistive switching memory cells were fabricated on a plastic substrate via inkjet printing (IJP) of a solid polymer electrolyte (SPE). Using the high contrast between the surface energy of a metal electrode and the substrate, a thin SPE film could be deposited over the electrode by IJP. The fabricated Ag/SPE/Pt cells showed bipolar resistive switching behavior under electrical bias in vacuum and in air, which is attributed to the formation and dissolution of a metal filament between the electrodes. From the standpoint of the switching mechanism, our cell can be referred to as a ‘gapless-type atomic switch’. The cells also exhibited stable switching behavior under substrate bending. This device fabrication technique has great potential for flexible switch/memory applications.

Effect of nanochitosan on electrochemical, interfacial and thermal properties of composite solid polymer electrolytes

PEO-based solid polymer electrolyte films with various concentrations of nanochitosan as filler and LiCF3SO3 as salt were prepared by membrane hot-press technique. Nanochitosan was prepared from chitosan by conventional chemical cure method. The prepared composite membranes were characterized by FT-IR, XRD, thermal, SEM, AFM analyses, electrochemical impedance spectroscopy, cyclic voltammetry and compatibility studies. The ionic conductivity and thermal stability of the polymer membranes were enhanced significantly by addition of nanofiller. The compatibility studies reveal that filler incorporated membrane is better compatible with lithium interface than filler free electrolyte.

Effect of complexing salt on conductivity of PVC/PEO polymer blend electrolytes

Solid polymer electrolyte membrane comprising poly(vinyl chloride) (PVC), poly(ehylene oxide) (PEO) and different lithium salts (LiClO4, LiBF4 and LiCF3SO3) were prepared by the solution casting technique. The effect of complexing salt on the ionic conductivity of the PVC/PEO host polymer is discussed. Solid polymer electrolyte films were characterized by X-ray diffraction, FTIR spectroscopy, TG/DTA and ac impedance spectroscopic studies. The conductivity studies of these solid polymer electrolyte (SPE) films are carried out as a function of frequency at various temperatures ranging from 302 K to 353 K. The maximum room temperature ionic conductivity is found to be 0·079 × 10−4 S cm−1 for the film containing LiBF4 as the complexing salt. The temperature dependence of the conductivity of polymer electrolyte films seems to obey the Vogel-Tamman-Fulcher (VTF) relation.

Fire-retardant solid polymer electrolyte films prepared from oxetane derivative with dimethyl phosphate ester group

Fire-retardant polymer electrolytes are key materials for safer operation of lithium secondary batteries and other large-size batteries than the batteries with organic liquid electrolyte. Solid polymer electrolyte systems with fire-retardant polymer matrixes have been investigated in only few cases. We prepare an oxetane derivative with dimethyl phosphate ester group (DPOX). The cross-linked poly(oxetane) matrixes for solid polymer electrolytes are prepared from DPOX and oxetane-based cross-linker (DDOE). DDOE has two oxetane rings at both of the ends of oligo-ethylene oxide chain. Conductivities in the range of 10 −5 S cm −1 have been obtained for self-extinguishing, ion-conductive cross-linked poly(oxetane) matrix with DPOX and DDOE monomers. Polarization behavior of a lithium electrode in the cross-linked poly(oxetane)-based electrolyte films is also investigated. The polarization curves show some hysteresis character with potential steps, however, deposition and stripping of lithium on the lithium electrode are observed.

Conductivity and optical studies of plasticized solid polymer electrolytes doped with carbon nanotube

Solid polymer electrolyte films based on Poly(ethylene oxide) (PEO) complexed with lithium hexafluorophosphate (LiPF 6), ethylene carbonate (EC) and amorphous carbon nanotube (αCNTs) were prepared by the solution cast technique. The conductivity increases from 10 −10 to 10 −5 Scm −1 upon the addition of salt. The incorporation of EC and αCNTs to the salted polymer enhances the conductivity significantly to 10 −4 and 10 −3 Scm −1. The complexation of doping materials with polymer were confirmed by X-ray diffraction and infrared studies. Optical properties like direct band gap and indirect band gap were investigated for pure and doped polymer films in the wavelength range 200–400 nm. It was found that the energy gaps and band edge values shifted to lower energies on doping.

Size effect of cubic ZrO2 nanoparticles on ionic conductivity of polyethylene oxide-based composite

A solvent free solid composite polymer electrolyte (SCPE) film consisting of high molecular mass polyethylene oxide (PEO) with sodium perchlorate (NaClO4) as electrolytic salt and cubic zirconium oxide (ZrO2) nanoparticles as the filler has been prepared by solution casting technique to influence the transport properties. X-ray diffraction and Fourier transform infrared spectroscopy confirm the formation of the SCPE film, whereas atomic force microscopy reveals the presence of a network of interconnected nanoparticles forming uniform surface feature of relatively low roughness. The highest ionic conductivity (σ = 6.96 × 10-5 S-cm-1) for PEO25 - NaClO4 with 5 wt. % ZrO2 nanoparticles of the smallest size 4.5 nm is an order of magnitude higher than the pure PEO25 - NaClO4 at room temperature. The conductivity enhancement is due to the creation of additional sites and favorable conduction pathways for ionic transport through Lewis acid-base type interactions between the polar surface groups of the ceramic filler and the electrolyte ionic species.

Effect of lithium salt concentrations on blended 49% poly(methyl methacrylate) grafted natural rubber and poly(methyl methacrylate) based solid polymer electrolyte

The effect of lithium salts (lithium tetrafluoroborate, LiBF 4 and lithium perchlorate, LiClO 4) as doping salts in rubber-polymer blends, 49% poly(methyl methacrylate) grafted natural rubber (MG49) and poly(methyl methacrylate) (PMMA) in solid polymer electrolyte (SPE) film for electrochemical devices application was investigated. The electrolyte films were prepared via the solution casting technique using 0–25 wt.% lithium salt. The effect of the lithium salts on chemical interaction, ionic conductivity and structural and morphological studies of (70:30) MG49-PMMA films was analyzed using Fourier Transform Infrared (FT-IR) Spectroscopy, Electrochemical Impedance Spectroscopy (EIS), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Infrared analysis showed that the interactions between lithium ions and oxygen atoms occur at the ether group (C–O–C) (1500–1100 cm −1) on the MMA structure in both MG49 and PMMA. The oxygen atoms in the structure of the polymer host act as electron donor atoms and form a coordinate bond with the lithium ions from the doping salt to form polymer–salt complexes. The ionic conductivity was investigated at room temperature as well as at a temperature range from 303 K to 373 K. The ionic conductivity without the addition of salt was 1.1 × 10 −12 S cm −1. The highest conductivity at room temperature for (70:30) MG49-PMMA–LiBF 4 was 8.6 × 10 −6 S cm −1 at 25 wt.% of LiBF 4. The ionic conductivity of (70:30) MG49-PMMA–LiClO 4 was 1.5 × 10 −8 S cm −1 at 25 wt.% of LiClO 4. However, both electrolyte systems do not exhibit Arrhenius-like behavior. Systems with LiBF 4 salt have higher ionic conductivity than those with LiClO 4 salt because of the differences in anionic size and lattice energy of the appropriate salt. The observations from structural and morphology studies showed that complexation and re-crystallization occur in the system. The XRD studies showed a reduction of the MMA peak intensity at 29.5° after the addition of 5–25 wt.% LiBF 4 salt due to ion dissociation in the electrolyte system. Thus, this contributed to the increase of ionic conductivity in (70:30) MG49-PMMA–LiBF 4. Morphological studies showed that (70:30) MG49-PMMA is homogenously blended, and no phase separation occurred. The addition of lithium salts changed the topological texture from a smooth and dark surface to a rough and bright surface.

Studies of Ionic Conductivity and Dielectric Behavior in Polyacrylonitrile Based Solid Polymer Electrolytes

The solid polymer electrolyte films consisting of polyacrylonitrile (PAN) as the host polymer, lithium triflate (LiCF3SO3) and sodium triflate (NaCF3SO3) as dopant salts were prepared by the solution cast technique. The pure PAN film was prepared as a reference. The films were characterized using a.c. impedance spectroscopy. At room temperature, the highest conductivity for the sample from the (PAN+LiCF3SO3) system and the (PAN+NaCF3SO3) system is 3.04 x 10-4 Scm-1 and 7.13 x 10-4 Scm-1, respectively. The temperature dependence of ionic conductivity for the highest conducting film from both systems follows the Arrhenius equation in the temperature range of 303 K to 353 K. The frequency dependence of ionic conductivity, , complex permittivity, *, and complex electrical modulus, M* were studied at different temperatures. The ionic conductivity and the dielectric behavior are described in terms of ion diffusion and polarization.

Characteristic evaluation of a solid polymer electrolyte sensor

This paper describes a development of a curvature sensor using a solid polymer electrolyte (SPE) film. The SPE film has good flexibility, and can be used in air. In previous research, we clarified output response to deformation of the SPE sensor and the relationship between sensor output and sensor curvature. In this paper, output characteristics of the SPE sensor are investigated in detail. Four sensors with different length and width are prepared. And the influence of the SPE sensor on the sensor element shape is investigated. As a result, it is confirmed that there are a several sensors which cause a slight reduction of the sensor output because it is difficult to place the whole sensor element on the sample curve exactly. Concerning with the large sensor, it was confirmed that the reduction of the sensor output is not occurred.

Layer-by-Layer Assembled Solid Polymer Electrolyte for Electrochromic Devices

A new solid polymer electrolyte film fabricated by layer-by-layer (LbL) assembly is presented. The electrolyte film consists of four interbonding layers per deposition cycle, which combines electrostatic and hydrogen bonding in the same structure. Linear poly(ethylene imine) (LPEI) and poly(ethylene oxide) (PEO) are used to enhance the dissolution of lithium salt and the ionic transport through segmental motions of polymer chains. Characterization of film structure and growth shows good incorporation of electrostatic and hydrogen bonding, because of the versatile control of the ionization of poly(acrylic acid) (PAA), which serves as a bridging molecule. Ionic conductivity values, as described by the Vogel−Fulcher−Tammann equation, are found to be above 10−5 S/cm for the dried electrolyte at room temperature and moderate humidity (52%RH). Thermal analysis reveals two competing processes, namely, cross-linking of LPEI and PAA to form an amide compound and segregation of PEO crystalline phase, which results in a moderate reduction of conductivity in the electrolyte after heating. Demonstration of solid electrochromic devices using the LbL-assembled polymer electrolyte is presented in both transmission and reflection mode with a modulation of 30%−40% in the visible and near-infrared range. The successful fabrication of the LbL-assembled electrolytes enables the realization of completely flexible, polymeric, and solid electrochromic devices.

Effect of plasticizer on structural and electrical properties of nanocomposite solid polymer electrolytes

The solid polymer electrolyte films based on polyethylene oxide, NaClO4 with dodecyl amine modified montmorillonite as filler, and polyethylene glycol as plasticizer were prepared by a tape casting method. The effect of plasticization on structural, microstructural, and electrical properties of the materials has been investigated. A systematic change in the structural and microstructural properties of plasticized polymer nanocomposite electrolytes (PPNCEs) on addition of plasticizer was observed in our X-ray diffraction pattern and scanning electron microscopy micrographs. Complex impedance analysis technique was used to calculate the electrical properties of the nanocomposites. Addition of plasticizer has resulted in the lowering of the glass transition temperature, effective dissociation of the salt, and enhancement in the electrical conductivity. The maximum value of conductivity obtained was ∼4.4 × 10−6 S cm−1 (on addition of ∼20% plasticizer), which is an order of magnitude higher than that of pure polymer nanocomposite electrolyte films (2.82 × 10−7 S cm−1). The enhancement in conductivity on plasticization was well correlated with the change in other physical properties.

A curvature sensor using a solid polymer electrolyte

This paper describes a development of a polymer sensor using a solid polymer electrolyte (SPE) film. The sensor has a basic structure that an SPE film is sandwiched between thin c arbon films, and conductive tapes are attached on each carbon film. The SPE film has a good flexibility and it is one of the most p romising electroactive polymers (EAP) with capability to be used as an actuator and a sensor in air. First a displacement sensor using the SPE film was fabricated. The response to deformation was investigated. Then a curvature sensor using the SPE film is proposed. In experiments, it was found that th e proposed sensor is available to measure curvature directly without complex calculations.

Investigations of (PVA)0.7(NaBr)0.3(H2SO4)xM solid acid polymer electrolyte using positron annihilation lifetime spectroscopy

The free-volumes of solid polymer electrolytes (SPE) were characterized using positron annihilation lifetime (PAL) spectroscopy, FTIR, and scanning electron microscope (SEM) techniques. The SPE based on poly(vinyl alcohol) (PVA) and sodium bromide (NaBr) complexed with sulfuric acid (SA) H2SO4 at different weight percent ratios were prepared using solution cast technique. The PAL results indicate that a higher SA content (more than 0.87 mol/L) in (PVA)0.7(NaBr)0.3 matrix increase the free-volume hole size from 58 A3 to 87 A3. The increase in the SPE free-volume with higher SA content was associated with a decrease in the SPE crystallinity. It is postulated that the incorporated SA interrupt polymeric chain packing and retard crystallization during electrolyte films formation. The FTIR spectral studies indicate that the SA content higher than 0.87 mol/L induces chemical modifications within the PVA, which results in chain scission. The PAL study shows that the chain scissions within the polymer matrix affect the free volume hole density (I3) and hence the microstructure. I3 was found to be decreased from ≃11 to ≃6 %, resulting in lower fractional free-volume holes in the SPE films. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 2038–2044, 2010

Materials and ion transport property studies on hot-press casted solid polymer electrolyte membranes: [(1 − x) PEO: x KIO 3

Materials and ion transport property characterization in Solid Polymer Electrolyte (SPE) membranes: (1 − x) PEO: x KIO 3, where x = 0, 10, 20, 30, 40, 50 wt.%, have been studied. SPE films have been prepared following two casting techniques: a novel hot-press (extrusion) and the traditional solution cast. Hot-press technique is a completely dry/solvent free/rapid/inexpensive procedure as compared to solution cast method and has recently been receiving wider acceptability to cast membranes of ion conducting polymeric electrolytes. ‘Log σ − x’ study revealed σ-maxima at salt concentration x = 30 wt.% for SPE film prepared by both the methods. However, hot-pressed SPE film: 70 PEO: 30 KIO 3 exhibited relatively higher room temperature conductivity ( σ ∼ 4.40 × 10 − 7 S cm − 1 ) than that of the solution casted film. This has been referred to as Optimum Conducting Composition (OCC) SPE film. Materials characterization in OCC SPE film has been done by XRD, FTIR and DSC techniques. These studies confirmed the complexation of salt in the polymeric host. Some basic ionic parameters viz. conductivity ( σ), ionic mobility (μ), mobile ion concentration (n), ionic transference number (t ion) have been determined using different experimental procedures to understand the ion transport behaviour in OCC SPE material. The temperature dependent conductivity measurement has also been carried out and the activation energy (E a) has been computed from the linear least square fitting of ‘log σ − 1 / T’ Arrhenius plot.

Hot-pressed Na+ion conducting solid polymer electrolytes: (1 - x) PEO: x NaPO3

Synthesis and ion transport property studies on hot-pressed Na+ ion conducting solid polymer electrolytes (SPEs): (1-x) PEO: x NaPO3, where x in wt.%, are reported. The compositional dependent conductivity (σ) studies revealed SPE film: (75PEO: 25NaPO3) as the optimum conducting composition (OCC) with room temperature conductivity σ ~ 6.7 × 10-7 S cm-1, which is more than two orders of magnitude higher than that of pure PEO polymer host (σ ~ 3.2 × 10-9 S cm-1). Materials characterization and polymer-salt complexation were done with the help of XRD, FTIR, SEM, DSC techniques. In order to understand the ion transport behaviour in SPEs, the measurement on some basic ionic parameters viz. ionic conductivity (σ), ionic mobility (μ), mobile ion concentration (n), ionic transference number (tion) have been carried out using different experimental techniques. The activation energy (Ea) values involved in the thermally activated conductivity processes have been computed from “log σ - 1/T” Arrhenius plots.

P-17 固体高分子電解質センサの特性評価(ポスター要旨講演)

This paper describes a characteristic evaluation of a solid polymer electrolyte (SPE) sensor. The sensor has a basic structure that the SPE film is sandwiched between thin carbon films. Each carbon is coated with Ag paste and they are covered with polymer films. SPE film has a good flexibility, and can be used in air. The SPE sensor output is related to the average of the curvature of the measured surface. In this paper, in order to obtain the output characteristics of the SPE sensor, the influence of the area size of the sensor element on the sensor output is investigated. As a result, it is found that the output is independent of the area size of the sensor element.

Solid polymeric electrolyte of poly(ethylene)oxide-50% epoxidized natural rubber-lithium triflate (PEO-ENR50-LiCF3SO3)

A solid polymer electrolyte (SPE) films consist-ing of polyethylene oxide (PEO), 50% epoxi-dized natural rubber (ENR50) and LiCF3SO3 with various compositions of PEO-ENR50 and vari-ous weight percentage of LiCF3SO3 were pre-pared by solution casting technique. The poly-mer electrolyte films were characterized using DSC, XRD and AC impedance spectroscopy. The SPE with the PEO-ENR50 composition of 70-30 shows the highest conductivity of 4.2 × 10-5 Scm-1 at the 15 wt.% of LiCF3SO3 compared with the other composition of PEO/ENR50. This composition was then chosen to investigate the effect of LiCF3SO3 on the thermal property, structure and conductivity of the electrolyte. The highest room temperature conductivity of 1.4 × 10-4 Scm-1 was achieved at 20 wt.% of LiCF3SO3. The conductivity result is supported by the DSC and XRD analysis which showed the semi- crystalline nature of PEO turning to amor-phous state due to the increase in LiCF3SO3 content.