Composite Polymer Electrolyte Films Research Articles

Conductivity enhancement in K+-ion conducting dry Solid Polymer Electrolyte (SPE): [PEO: KNO3]: A consequence of KI dispersal and nano-ionic effect

Flexible films of dry Solid Polymer Electrolytes (SPEs): [PEO: KNO3] in varying salt concentrations have been hot-press cast. Salt concentration dependent conductivity study revealed two SPE films: [95PEO: 5KNO3] and [70PEO: 30KNO3] exhibiting relatively higher room temperature conductivity (σrt) ∼ 2.76 × 10−7 S/cm and ∼4.31 × 10−7 S/cm respectively. In order to increase σrt further, two strategies have been adopted. Firstly, fractional amount of KI has been dispersed as IInd-phase active filler into above two SPE film compositions which acted as Ist-phase host and Composite Polymer Electrolyte (CPE) films were hot-press cast. Filler particle concentration dependent conductivity study identified CPE films: [(95PEO: 5KNO3) + 7KI] and [(70PEO: 30KNO3) + 10 KI] as optimum conducting films with σrt ∼ 6.15 × 10−6 S/cm and ∼3.98 × 10−6 S/cm respectively. σrt-enhancement of approximately an order of magnitude was achieved by this approach. In second approach, dry powder mixture of (KNO3 + KI), in ratio that of above two CPE films, were subjected to high energy ball-milling separately for different durations prior to casting the films again. The conductivity measurements as a function of milling time identified CPE films: [(95PEO: 5KNO3) + 7KI] and [(70PEO: 30KNO3) + 10 KI] in which two respective (KNO3 + KI) ratios milled for 4- and 6-h, exhibited almost similar value of σrt ∼ 2.09 × 10−5 S/cm. This approach increased σrt further by ∼3–6 fold. The reason attributed for this has been Nano–ionic effect introduced at the interphase boundaries between KNO3 and KI, as a consequence of milling. These films have been referred to as milled CPE films. Subsequently, all the optimum conducting SPE and CPE (unmilled/milled) films were subjected to various characterization studies in order to evaluate their utility in potential All–Solid–State batteries. Ion transport behaviour has been characterized in terms of ionic conductivity (σ), total ionic (tion) and cation (t+) transference numbers, evaluated using different ac/dc techniques. Temperature dependent conductivity measurements have also been done to compute activation energy (Ea) value by linear least square fitting of respective ‘log σ −1/T’ plots. Materials characterization vis-a-vis complexation of salt in polymeric host has been confirmed by SEM/XRD/FTIR/DSC analysis.

Electrical Impedance Studies on Sodium Ion Conducting Composite Blend Polymer Electrolyte

Sodium ion conducting polymer blend thin films are of technologically interesting due to the tuned physical and electrical properties with wide variety of applications like sodium sulphur batteries, thermoelectric generators, electrochemical sensors, etc. sodium ion conducting composite blend polymer electrolyte films, based on poly vinyl alcohol (PVA) and poly(vinyl pyrrolidone) (PVP) complexed with NaCl were prepared by solution casting technique. The prepared films were characterized by various methods. The complexation of the salt with the polymer blend was identified by X-ray diffraction and Fourier transforms infrared spectroscopy. DSC was used to analyze the thermal behavior of the samples and the glass transition temperature is low for the highest conducting polymer material. The Frequency and temperature dependent of electrical conductivities of the films were studied using impedance analyzer in the frequency range of 1 Hz–1 MHz. The higher electrical conductivity of 50 PVA:50 PVP:15 wt% NaCl concentration has been found to be 1.747 × 10−3 Scm−1 at room temperature. The electrical permittivity of the polymer films have been studied for various temperatures.

The grafting reaction of epoxycyclohexyl polyhedral oligomeric silsesquioxanes with carboxylic methoxypolyethylene glycols and the properties of composite solid polymer electrolytes with the graftomer

ABSTRACTA novel organic–inorganic hybrid of epoxycyclohexyl polyhedral oligomeric silsesquioxane (e‐POSS)–grafted carboxylic methoxypolyethylene glycols (mPEG‐COOH), that is, a POSS‐mPEG graftomer, was synthesized. The grafting reaction of e‐POSS and mPEG‐COOH was characterized by Fourier transform infrared (FTIR) and 1H‐NMR spectroscopy. Then the graftomer was used to develop new composite solid polymer electrolyte (SPE) films with a carboxylated nitrile rubber–epoxidized natural rubber (XNBR‐ENR) self‐crosslinked blend system as a dual‐phase polymer matrix. The self‐crosslinked reaction of the XNBR‐ENR matrix was investigated using ATR‐FTIR. The morphology of the SPE films and the distribution of lithium salt were investigated using field emission scanning electron microscopy and X‐ray diffraction, and the result illustrated that the addition of POSS‐mPEG could promote and accelerate the dissociation of LiClO4. The best effect within the range of this study was achieved when 25 phr POSS‐mPEG was involved. The differential scanning calorimetry analysis proved that the glass‐transition temperature of the composite SPE films was reduced with the increase of POSS‐mPEG. The ionic conductivity of the composite SPE films was investigated by electrochemical impedance spectroscopy. The highest ionic conductivity in this study of 2.57 × 10−5 S cm−1 was obtained with 25 phr POSS‐mPEG loading. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44460.

Enhancement of Li+ ion conductivity in solid polymer electrolytes using surface tailored porous silica nanofillers

The current study represents the design and synthesis of polyethylene oxide (PEO)-based solid polymer electrolytes by solvent casting approach using surface tailored porous silica as nanofillers. The surface tailoring of porous silica nanostructure is achieved through silanization chemistry using 3-glycidyloxypropyl trimethoxysilane in which silane part get anchored to the silica surface whereas epoxy group get stellated from the silica surface. Surface tailoring of silica with epoxy group increases the room temperature electrochemical performances of the resulting polymer electrolytes. Ammonical hydrolysis of organosilicate precursor is used for both silica preparation and their surface tailoring. The composite solid polymer electrolyte films are prepared by solution mixing of PEO with lithium salt in presence of silica nanofillers and cast into film by solvent drying, which are then characterized by impedance measurement for conductivity study and wide angle x-ray diffraction for change in polymer crystallinity. Room temperature impedance measurement reveals Li+ ion conductivity in the order of 10−4 S cm−1, which is correlated to the decrease in PEO crystallinity. The enhancement of conductivity is further observed to be dependent on the amount of silica as well as on their surface characteristics.

Composite Solid Polymer Electrolyte Membrane

Due to safety issues in the lithium batteries with organic liquid electrolytes, it is expected that the next-generation safe lithium batteries would be the all-solid-state batteries. New solid electrolytes with high Li+ ion conduction such as Li10GeP2S12, Li1.3Al0.3Ti1.7(PO4)3 and Li7La3Zr2O12 have attracted extensive attentions in the development of solid-state batteries. Especially, the garnet-type material Li7La3Zr2O12 has several advantageous properties such as good thermal and chemical stability with lithium metal anode, environmental compatibility, relatively high Li+ion conductivity. However, the poor contact between electrodes and electrolyte is a most important factor limiting the development of LLZO all-solid-state battery. So we combining P(VDF-HFP) polymer electrolyte and LLZO powder and painting it on the fiberglass to construct composite solid polymer electrolyte. The SEM micrographs of the with 30wt% LLZO added are shown in Fig.1. There are obvious powder have attaching to the fiberglass surface and the polymer on it. Fig.2. compared rate capability of the composite solid polymer electrolyte film and the fiberglass. Founding that the composite system can obviously increasing it. Fig.1 SEM micrographs of the composite solid polymer electrolyte. Fig.2 Rate capability of the composite solid polymer electrolyte film and the fiberglass. Acknowledgements The project was supported by the National Natural Science Foundation of China (21373137), Shanghai Science and Technology Development Fund (15DZ2282000) and the Foundation of China (NSFC21373137). Figure 1

Ag+-ion conducting Nano-Composite Polymer Electrolytes (NCPEs): Synthesis, characterization and all-solid-battery studies

Ag+-ion conducting Nano Composite Polymer Electrolyte (NCPE) films: [90PEO: 10AgCF3SO3]+xAl2O3, where x=0.5, 1, 1.5, 2, 3, 4, 5wt.(%), have been prepared by a completely dry hot-press technique in place of the traditional solution-cast method. NCPE film, basically a two-phase organic composite polymer electrolyte, has been synthesized using Solid Polymer Electrolyte (SPE) composition: [90PEO: 10AgCF3SO3], identified as one of the high conducting films with room temperature (300K) ionic conductivity (σrt)~7.12×10−7S/cm and having superior mechanical flexibility, as 1st-phase host and nano-particles (size<50nm) of an insulating/inert filler material Al2O3 as 2nd-phase dispersoid. Filler particle concentration dependent conductivity measurements revealed NCPE film: [(90PEO: 10AgCF3SO3)+3Al2O3] as Optimum Conducting Composition (OCC) with σrt~2.57×10−6S/cm. A conductivity enhancement of more than 3-fold could be achieved in SPE as a consequence of dispersal of Al2O3 nano-particles. Also, NCPE OCC film physically appeared relatively more stable/flexible as compared to SPE host film. The characterization of ion transport properties in SPE host and NCPE OCC films has been done in terms of ionic conductivity (σ) and total ionic (tion)/cation (t+) transference numbers. These ionic parameters have been evaluated experimentally using different ac/dc techniques. The temperature dependent conductivity has also been studied and the activation energy (Ea) was computed by liner least square fitting of Arrhenius plot. The material characterization was done by analyzing X-ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) responses on the film samples. All-Solid-State batteries in the cell configuration Ag (anode)//NCPE OCC film//(I2+C+NCPE) (cathode) have been fabricated and the cell-potential discharge performances have been studied under varying load conditions. An Open Circuit Voltage (OCV)~0.56V was obtained. Some important cell parameters have been evaluated from the cell potential discharge profiles. The battery performed quite satisfactorily especially under low current drain states.

Effect of nano TiO2 filler on the structural and electrical properties of PVP based polymer electrolyte films

A composite polymer electrolyte system based on PVP:KIO4 with dispersed nano TiO2 filler in different concentrations was prepared by solution casting. Structural investigations were carried out using X-ray diffraction, Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). Electrical conductivity measurements were performed by a computer controlled phase sensitive multimeter (PSM 1700) in the frequency and temperature range 1 Hz–1 MHz and 303–373 K, respectively. It was observed that the magnitude of conductivity increased with increase in the nano TiO2 filler concentration as well as with temperature. The addition of nano TiO2 filler to the PVP:KIO4 electrolyte system was found to result in enhancement of the ionic conductivity. The maximum ionic conductivity 0.665 × 10−3 S/cm was obtained for 10 wt% nano TiO2 filler in the composite at room temperature. The conducting species of charge transport in these nano composite polymer electrolyte films were examined by the Watanabe technique and it was found that the charge transport is predominantly due to cations. Using these polymer electrolytes (KIO4 complexed and TiO2 nano composite), electrochemical cells were fabricated with the configuration of K/(Polymer film)/(I2 + C + electrolyte), and discharge characteristics were studied under a constant load of 100 kΩ. Various cell parameters, such as open circuit voltage, short circuit current, power density and energy density were determined.

Study on Ion Conductivity and Crystallinity of Composite Polymer Electrolytes Based on Poly(ethylene oxide)/Poly(acrylonitrile) Containing Nano-Sized Al&lt;SUB&gt;2&lt;/SUB&gt;O&lt;SUB&gt;3&lt;/SUB&gt; Fillers

In this paper, composite polymer electrolytes were prepared by a blend of poly(ethylene oxide) (PEO) and poly(acrylonitrile) (PAN) as a polymer matrix, ethylene carbonate as a plasticizer, LiClO4 as a salt, and by containing a different content of nano-sized Al2O3. The composite films were prepared by using the solution casting method. The crystallinity and ionic conductivity of the polymer electrolytes was investigated using X-ray diffraction (XRD) and AC impedance method, respectively. The morphology of composite polymer electrolyte film was analyzed by SEM method. From the experimental results, by increasing the Al2O3 content, the crystallinity of PEO was reduced, and the ionic conductivity was increased. In particular, by a doping of 15 wt.% Al2O3 in PEO/PAN polymer blend, the CPEs showed the superior ionic conductivity. However, when Al2O3 content exceeds 15 wt.%, the ionic conductivity was decreased. From the surface morphology, it was concluded that the ionic conductivity was decreased because the CPEs showed a heterogenous morphology due to immiscibility or aggregation of the ceramic filler within the polymer matrix.

Effect Of Al2O3 ceramic Filler On PEG-based Composite Polymer electrolytes For Magnesium Batteries

Composite polymer electrolyte films consisting of polyethylene glycol (PEG), Mg(CH3COO)2 and Al2O3 particles have been prepared by solution casting technique. The X-ray diffraction patterns of PEG-Mg(CH3COO)2 with Al2O3 ceramic filler, indicates the decrease in the degree of crystallinity with increasing concentration of the filler. The role of ceramic phase is to reduce the melting temperature which is ascertained from the DSC. The effect of ceramic filler on the conductivity of the polymer electrolyte was studied. The maximum ionic conductivity has been observed for 10 wt% of Al2O3 at room temperature (303 K). The transference number data indicated the dominance of ion-type charge transport in these composite polymer electrolytes. Using this (PEG-Mg(CH3COO)2-Al2O3) (85–15–10) electrolyte, solid-state electrochemical cell was fabricated and their discharge profiles were studied under a constant load of 100 kΩ. Several cell profiles associated with this cell were evaluated and are reported.

Effect of NiO nanofiller concentration on the properties of PEO-NiO-LiClO4 composite polymer electrolyte

Composite polymer electrolyte films comprising polyethylene oxide (PEO) as the polymer host, LiClO4 as the dopant, and NiO nanoparticle as the inorganic filler was prepared by solution casting technique. NiO inorganic filler was synthesized via sol-gel method. The effect of NiO filler on the ionic conductivity, structure, and morphology of PEO-LiClO4-based composite polymer electrolyte was investigated by AC impedance spectroscopy, X-ray diffraction, and scanning electron microscopy, respectively. It was observed that the conductivity of the electrolyte increases with NiO concentration. The highest room temperature conductivity of the electrolyte was 7.4 × 10−4 S cm−1 at 10 wt.% NiO. The observation on structure shows the highest conductivity appears in amorphous phase. This result has been supported by surface morphology analysis showing that the NiO filler are well distributed in the samples. As a conclusion, the addition of NiO nanofiller improves the conductivity of PEO-LiClO4 composite polymer electrolyte.

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.

Morphology and Electrical Characteristics of (PEO)&lt;sub&gt;10&lt;/sub&gt;LiClO&lt;sub&gt;4&lt;/sub&gt; Electrolyte with Nanosized CeO&lt;sub&gt;2&lt;/sub&gt;

In the present work, using nanosized rare earth oxide CeO2 as filler and acetonitrile as organic solvent, a novel solid-state composite polymer electrolyte (CPE) films (PEO)10LiClO4-x wt.%CeO2 (x=0,2,6,9,12,15) was prepared by solution-casting technique. The effect of CeO2 filler concentration on morphology and electrical characteristics of CPE films has been investigated and analyzed. The AC impedance measurements show that the ionic conductivity of CPE can be efficiently enhanced by adding appropriate CeO2. The highest room temperature (25OC) ionic conductivity of 1.71×10-5S•cm-1 is achieved with the CeO2 content of 9 wt.%. With the CeO2 content continues to increase, CPE ionic conductivity begin to decline. This is because appropriate CeO2 can disorder the chain structure and effectively inhibit the crystallization of PEO, which expands the amorphous region required for the lithium-ion transport.

Enhanced Li + conductivity in PEO–LiBOB polymer electrolytes by using succinonitrile as a plasticizer

In this paper, a series of poly(ethylene oxide)-based composite polymer electrolyte films containing variable content of organic non-ionic plasticizer (succinontrile) have been successfully prepared by using self-made lithium bis(oxalate)borate as the thermally stable, environmentally friendly and low-cost lithium salt. All of the films were investigated with XRD, DSC, SEM and EIS technologies. It is found that both the large-sized bis(oxalate)borate anions (compared with ClO 4 −) and the highly polar succinontrile plasticizer have remarkable and positive effects on their crystalline structures, thermal properties and Li + conductivities. Moreover, all the films are flexible and self-standing, and their Li + conductivities are highly stable, which further ensures their potential applications as electrolytes for Li-ion polymer batteries.

Enhanced ionic conductivity in oxygen ion irradiated poly(vinylidene fluoride-hexafluoropropylene) based nanocomposite gel polymer electrolytes

In the present work, effect of Swift Heavy Ion (SHI) irradiation by 90 MeV O 7+ ion with four different fluences on P(VdF − HFP)–(PC + DEC)–LiClO 4-dedoped (insulating) polyaniline (PAni) nanofibers polymer electrolytes have been investigated. The irradiated films have been investigated by ac impedance, XRD, FTIR, DSC and SEM analyses. It has been observed that irradiation with swift heavy ion shows increase in ionic conductivity of the composite gel polymer electrolyte films at lower fluences (≤10 11 ions/cm 2) and decrease at higher fluences (≥10 11 ions/cm 2) as compared to the unirradiated film. Maximum ionic conductivity of 1.2 × 10 − 2 S/cm at room temperature has been found after irradiation with fluence 10 11 ions/cm 2. The increase in ionic conductivity at lower fluences could be attributed to the scissioning of polymer bonds, which leads to larger segmental motion of polymer backbone resulting in faster ionic transport through the polymer matrix. However at higher fluences (≥10 11 ions/cm 2) the polyaniline nanofibers get phase separated out from P(VdF − HFP)–(PC + DEC)–LiClO 4 leading to decrease in ionic conductivity. The phase separation phenomenon has been confirmed by DSC, FTIR and dielectric loss spectra. The surface morphology of the irradiated films has been examined by SEM.

Preparation and properties of PEO/LiClO4/KH560-SiO2 composite polymer electrolyte by sol-gel composite-in-situ method

Composite polymer electrolytes based on polyethylene oxide(PEO) were prepared by using LiClO4 as doping salt and silane-modified SiO2 as filler. SiO2 was formed in-situ in (PEO)8LiClO4 matrix by the hydrolysis and condensation reaction of Si(OC4H9)4. The crystallinity, morphology and ionic conductivity of composite polymer electrolyte films were examined by differential scanning calorimetry, scanning electron microscopy, atom force microscopy and alternating current impedance spectroscopy, respectively. Compared with the crystallinity of the unmodified SiO2 as inert filler, that of composite polymer electrolytes is decreased. The results show that silane-modified SiO2 particles are uniformly dispersed in (PEO)8LiClO4 composite polymer electrolyte film and the addition of silane-modified SiO2 increases the ionic conductivity of the (PEO)8LiClO4 more noticeably. When the mass fraction of SiO2 is about 10%, the conductivity of (PEO)8LiClO4-modified SiO2 attains a maximum value of 4.8×10−5 S·cm−1.

Characterization, microstructure, and gas sensitive response behavior of PEG/lithium salt polymer electrolyte films

A composite polymer electrolyte film was prepared by dissolving polyethylene glycol (PEG) with different molecular weight in acetonitrile, and vapor-induced response behavior was investigated upon exposure to various chemical environments. The effect of lithium concentrations on ionic conductivity and response was discussed. The surface microporous structures and vapor sensitive conductivity of the films in the case of poly(vinylidene fluoride) (PVDF) were examined with the PVDF content changed. The crystalline and micro-phase isolation behavior were characterized by a differential scanning calorimeter, an environmental scanning electron microscope, a polarization microscope and a wide-angle X-ray diffraction. The experimental results indicated that PEG/Li+ salt composite films exhibited preferential responsive characteristics. The responsivities to ethanoic acid, chloroform, and acetone vapors were enhanced with molecular weight of PEG increased. The conductivity was increased at a higher lithium salt concentration, and also enhanced with PEG content increased, while the responsivities decreased. The formation of microporous structures on the surface of the mixed PEG/PVDF composite films enlarged their specific area and strikingly improved the responsive performances. The changes in conduction behavior were explained from the viewpoint of the swelling and free volume theories as well as a hydrogen bond interaction, combined with the structural and morphological analyses. The introduction of an ionogenic matter also has an important effect on ionic conductivity and responsiveness.

Morphology and conductivity of in-situ PEO-LiClO4-TiO2 composite polymer electrolyte

PEO-LiClO4-TiO2 composite polymer electrolyte films were prepared. TiO2 was formed directly in matrix by hydrolysis and condensation reaction of tetrabutyl titanate. The crystallinity, morphology and ionic conductivity of composite polymer electrolyte films were examined by differential scanning calorimetry, scanning electron microscopy, atom force microscopy and alternating current impedance spectroscopy, respectively. The glass transition temperature and the crystallinity of composite polymer electrolytes are decreased compared with those of PEO-LiClO4 polymer electrolyte film. The results show that TiO2 particles are uniformly dispersed in PEO-LiClO4-5%TiO2 composite polymer electrolyte film. The maximal conductivity of 5.5×10−5 S/cm at 20 °C of PEO-LiClO4-TiO2 film is obtained at 5% mass fraction of TiO2.

Mesoporous silica (MCM-41) effect on (PEO+LiAsF6) solid polymer electrolyte

Composite polymer electrolyte films consisting of polyethylene oxide (PEO), LiAsF 6 and mesoporous silica (MCM-41) with fixed PEO/LiAsF 6 = 90/10 but different weight percent ratios of MCM-41 were prepared using the solution casting method. The polymer electrolyte films were characterized using XRD, DSC, SEM and electrical impedance spectroscopy. In corporation of MCM-41 in a (PEO + LiAsF 6 ) polymer electrolyte facilitates salt dissociation, enhances ion conductivity, and improves miscibility between organic and inorganic moieties. The scanning electron microscopy (SEM) photographs indicates the electrolytes are miscible and homogeneous up to 10 wt.% of MCM-41, and an optimized conductivity is found at this composition (10 wt.%). However, at higher weight ratios (>10 wt.%), the Li/MCM-41-rich domain developed, and the conductivity decreased with increasing mesoporous material. The electrochemical performance of fabricated electrochemical cells of configuration Li/(PEO + LiAsF 6 + MCM-41)/(MoO 3 + C + PTFE) were investigated.

Structural, Electrical and Optical Characterization of Pure and Doped Poly (Vinyl Alcohol) (PVA) Polymer Electrolyte Films

A sodium ion conducting polymer electrolyte based on Poly (Vinyl Alcohol) (PVA) complexed with Sodium Iodide (NaI) was prepared using solution cast technique. The structural properties of composite PVA polymer electrolyte films were examined by XRD. The XRD results revealed that the amorphous domains of PVA polymer matrix increased in size with the increase of NaI salt concentration. The variation in film morphology was examined by scanning electron microscopy. FT-IR spectra studies for pure PVA and complexed films revealed the vibrational changes that occurred due to the effect of dopant salt in the polymer. DC conductivity was measured in the temperature range of 303–373° K and the conductivity was found to increase with the increase of dopant concentration as well as temperature. Optical absorption studies were made in the wavelength range 200–600 nm. The absorption edge, direct band gap, and indirect band gap values were evaluated.

Characterization of (PEO)LiClO4‐Li1.3Al0.3Ti1.7(PO4)3 composite polymer electrolytes with different molecular weights of PEO

AbstractA group of polyethylene oxide (PEO)LiClO4‐Li1.3Al0.3Ti1.7(PO4)3 composite polymer electrolyte (CPE) films was prepared by the solution‐cast method. In each film, EO/Li = 8 and the Li1.3Al0.3Ti1.7(PO4)3 content of 15 wt % were fixed, but the number averaged molecular weight of PEO (Mn) was altered from 5 to 7 × 104 to 106, 2.2–2.7 × 106, 3–4 × 106, 4–5 × 106, and 5.5–6 × 106, respectively. Several techniques including X‐ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and electrical impedance spectroscopy (EIS) were used to characterize the CPE films. LiClO4 was found to have a strong tendency to complex with PEO, but Li1.3Al0.3Ti1.7(PO4)3 was rather dispersed in PEO matrix. DSC analysis revealed that the amorphous phase was dominant in the CPE films although the PEOs before‐use was considerably crystalline. SEM study showed smooth and homogeneous morphologies of the films with low molecular weight PEO and a dual phase characteristic for those with high molecular weight PEO. EIS results indicated that the CPE films are all ionic conductor and the conducting behavior obeys Vogel‐Tamman‐Fulcher (VTF) equation. The parameters in VTF equation were obtained and discussed by taking into considerations PEO molecular weights and crystallinities of the CPE films. Of all the films, the one with PEO with the smallest Mn = 5–7 × 104 had the maximum conductivity, i.e., 1.590 × 10−5 S cm−1 at room temperature and 1.886 × 10−3 S cm−1 at 373 K. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4269–4275, 2006