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1.
In this paper, we report an enhancement in ionic conductivity in a new nano-composite solid polymer electrolyte namely, (PEG)
x
LiBr: y(SiO 2). The samples were prepared, characterized, and investigated by XRD, IR, NMR, and impedance spectroscopy. Conductivity as
a function of salt concentration shows a double peak. Five weight percent addition of silica nanoparticles increases the ionic
conductivity by two orders of magnitude. Conductivity exhibits an Arrhenius type dependence on temperature. IR study has shown
that the existence of nanoparticles in the vicinity of terminal O―H group results in a shift in IR absorption frequency and
increase in amplitude of vibration of the terminal O―H group. This might lead to an enhancement in conductivity due to increased
segmental motion of the polymer. 7Li NMR spectroscopic studies also seem to support this. Thus addition of nanoparticle inert fillers still seems to be a promising
technique to enhance the ionic conductivity in solid polymer electrolytes. 相似文献
2.
Nano-composite polymer gel electrolytes were synthesized by using polyethylene oxide (PEO), ammonium tetrafluoroborate (NH4BF4), fumed silica (SiO2), dimethylacetamide (DMA), ethylene carbonate (EC), and propylene carbonate (PC) and characterized by conductivity studies. The effect of donor number of solvent on ionic conductivity of polymer gel electrolytes has been studied. The mechanical strength of the gel electrolytes has been increased with the addition of nano-sized fumed silica along with an enhancement in conductivity. Maximum room temperature ionic conductivity of 2.63 × 10−3 and 2.92 × 10−3 S/cm has been observed for nano-composite gel electrolytes containing 0.1 and 0.5 wt% SiO2 in DMA+1 M NH4BF4+10 wt% PEO, respectively. Nano-composite polymer gel electrolytes having DMA have been found to be thermally and electrically stable over 0 to 90 °C temperature range. Also, the change in conductivity with the passage of time is very small, which may be desirable to make applicable for various smart devices. 相似文献
3.
A solid polymer electrolyte (SPE) is synthesized by solution casting technique. The SPE uses poly(ethylene oxide) PEO as a host matrix doped with lithium triflate (LiCF 3SO 3), ethylene carbonate (EC) as plasticizer and nano alumina (Al 2O 3) as filler. The polymer electrolytes are characterized by Impedance Spectroscopy (IS) to determine the composition of the additive which gives the highest conductivity for each system. At room temperature, the highest conductivity is obtained for the composition PEO-LiCF 3SO 3-EC-15%Al 2O 3 with a value of 5.07 10 − 4 S/cm. The ionic conductivity of the polymer electrolytes increases with temperature and obeys the Arrhenius law. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) studies indicate that the conductivity increase is due to an increase in amorphous content which enhances the segmental flexibility of polymeric chains and the disordered structure of the electrolyte. Fourier transform infrared spectroscopy (FTIR) spectra show the occurrence of complexation and interaction among the components. Scanning electron microscopy (SEM) images show the changes morphology of solid polymer electrolyte. 相似文献
4.
Solid polymer electrolyte PEO 9 Mg(ClO 4) 2 incorporating 10 wt.% nano-porous Al 2O 3 filler grains has been prepared by the solvent casting technique using acetonitrile as the common solvent. Al 2O 3 powder (activated acidic, Aldrich) with grain size 104 μm and pore size 5.8 nm were incorporated as an inert filler. Electrolyte films have been characterized by differential scanning calorimetry, complex impedance and dc polarization measurements. The nano-composite electrolyte as well as the filler-free electrolyte appear to be predominantly anionic conductors with ClO 4− ions being the migrating species. The presence of the alumina filler has enhanced the ionic conductivity significantly. The conductivity enhancement has been attributed to Lewis acid–base type interactions between H groups at the filler grain surface and the ClO 4− ions. Transient H-bonding through these interactions is expected to provide additional hopping sites and favourable conducting pathways for migrating ionic species. 相似文献
5.
The ionic conductivity and dielectric properties of the solid nanocomposite polymer electrolytes formed by dispersing a low particle-sized TiO 2 ceramic filler in a poly (ethylene oxide) (PEO)-AgNO 3 matrix are presented and discussed. The solid nanocomposite polymer electrolytes are prepared by hot press method. The optimum conducting solid polymer electrolyte of polymer PEO and salt AgNO 3 is used as host matrix and TiO 2 as filler. From the filler concentration-dependent conductivity study, the maximum ionic conductivity at room temperature is obtained for 10 wt% of TiO 2. The real part of impedance ( Z′) and imaginary part of impedance ( Z″) are analyzed using an LCR meter. The dielectric properties of the highest conducting solid polymer electrolyte are analyzed using dielectric permittivity (ε′), dielectric loss (ε″), loss tangent (tan δ), real part of the electric modulus ( M′), and imaginary part of the electric modulus ( M″). It is observed that the dielectric constant ( ε′) increases sharply towards the lower frequencies due to the electrode polarization effect. The maxima of the loss tangent (tan δ) shift towards higher frequencies with increasing temperature. The peaks observed in the imaginary part of the electric modulus ( M″) due to conductivity relaxation shows that the material is ionic conductor. The enhancement in ionic conductivity is observed when nanosized TiO 2 is added into the solid polymer electrolyte. 相似文献
6.
Ion-conducting thin film polymer electrolytes based on poly(ethylene oxide) (PEO) complexes with NaAlOSiO molecular sieves
powders has been prepared by solution casting technique. X-ray diffraction, scanning electron microscopy, differential scanning
calorimeter, and alternating current impedance techniques are employed to investigate the effect of NaAlOSiO molecular sieves
on the crystallization mechanism of PEO in composite polymer electrolyte. The experimental results show that NaAlOSiO powders
have great influence on the growth stage of PEO spherulites. PEO crystallization decrease and the amorphous region that the
lithium-ion transport is expanded by adding appropriate NaAlOSiO, which leads to drastic enhancement in the ionic conductivity
of the (PEO) 16LiClO 4 electrolyte. The ionic conductivity of (PEO) 16LiClO 4-12 wt.% NaAlOSiO achieves (2.370 ± 0.082) × 10 −4 S · cm −1 at room temperature (18 °C). Without NaAlOSiO, the ionic conductivity has only (8.382 ± 0.927) × 10 −6 S · cm −1, enhancing 2 orders of magnitude. Compared with inorganic oxide as filler, the addition of NaAlOSiO molecular sieves powders
can disperse homogeneously in the electrolyte matrix without forming any crystal phase and the growth stage of PEO spherulites
can be hindered more effectively. 相似文献
7.
The thin-film solid polymer electrolyte based on polyethylene oxide (PEO) with sodium chlorite (NaClO 3) has been prepared by a solution-cast technique. The electrolyte was characterized by X-ray diffraction (XRD), infrared (IR),
cyclic voltammetry, alternating current conductivity, and Wagner’s polarization studies. The complexation of NaClO 3 with PEO was confirmed through the XRD and IR studies. The transference number measurement has shown that the ion transport
is predominant over electrons in the polymer electrolytes ( t
ions ≈ 0.94). The conductivity enhancement was observed in the case of the PEO/NaClO 3 system with the addition of plasticizers (low-molecular-weight polyethylene glycol, organic solvents propylene carbonate
and dimethyl formamide. Cyclic voltammetry analysis showed the stability and redox character of the electrolyte and electrode.
Finally, polymer electrolyte systems were examined by electrochemical cell studies using V 2O 5 and composite V 2O 5 cathode at temperature of 35 °C. Overall, the plasticized electrolyte shows a better electrochemical performance, and a higher
discharge capacity was observed in composite V 2O 5-based cells over V 2O 5-based cells. 相似文献
8.
Solid polymer electrolytes consisted of poly(ethylene oxide) (PEO) and poly(methyl methacrylate) (PMMA) blend (50:50 wt/wt%) with lithium triflate (LiCF 3SO 3) as a dopant ionic salt at stoichiometric ratio [EO + (CO)]:Li + = 9:1, poly(ethylene glycol) (PEG) as plasticizer (10 wt%) and montmorillonite (MMT) clay as nanofiller (3 wt%) have been prepared by solution cast followed by melt–pressing method. The X–ray diffraction study infers that the (PEO–PMMA)–LiCF 3SO 3 electrolyte is predominantly amorphous, but (PEO–PMMA)–LiCF 3SO 3–10 wt% PEG electrolyte has some PEO crystalline cluster, whereas (PEO–PMMA)–LiCF 3SO 3–10 wt% PEG–3 wt% MMT electrolyte is an amorphous with intercalated and exfoliated MMT structures. The complex dielectric function, ac electrical conductivity, electric modulus and impedance spectra of these electrolytes have been investigated over the frequency range 20 Hz to 1 MHz. These spectra have been analysed in terms of the contribution of electrode polarization phenomenon in the low frequency region and the dynamics of cations coordinated polymer chain segments in the high frequency region, and also their variation on the addition of PEG and MMT in the electrolytes. The temperature dependent dc ionic conductivity, dielectric relaxation time and dielectric strength of the plasticized nanocomposite electrolyte obey the Arrhenius behaviour. The mechanism of ions transportation and the dependence of ionic conductivity on the segmental motion of polymer chain, dielectric strength, and amorphicity of these electrolytes have been explored. The room temperature ionic conductivity values of the electrolytes are found ∼10 −5 S cm −1, confirming their use in preparation of all-solid-state ion conducting devices. 相似文献
9.
The polyethylene oxide (PEO) based lithium ion conducting polymer electrolytes complexed with lithium trifluoromethanesulfonate (LiCF 3SO 3 or LiTf) plasticized with an ionic liquid 1-ethyl 3-methyl imidazolium trifluoromethanesulfonate (EMITf) have been reported. Morphological, spectroscopic, thermal and electrochemical investigations demonstrate promising characteristics of the polymer films, suitable as electrolyte in various energy storage/conversion devices. Significant structural changes have been observed in the polymer electrolyte due to the ionic liquid addition, investigated by X-ray diffraction (XRD) and optical microscopy. The ion-polymer interaction, particularly the interaction of imidazolium cation with PEO chains, has been evidenced by IR and Raman spectroscopic studies. The optimized composition of the polymer electrolyte i.e. PEO 25.LiTf + 40 wt.% EMITf offer room temperature ionic conductivity of ~ 3 × 10 − 4 S cm − 1 with wide electrochemical stability window and excellent thermal stability. The ‘σ versus 1/T’ curves show apparent Arrhenius behavior below and above melting temperature. The ionic conductivity has been observed due to Li + ions, as confirmed from 7Li-NMR studies, though the component ions of ionic liquid and anions also contribute significantly to the overall conductivity. 相似文献
10.
Gel electrolytes and solid electrolytes have been reported as a potential element to slow down the polysulfide shuttle by reducing its mobility in the electrolytes. The preparation of sulfur-conductive polymer composites, or sulfur-carbon composites, has been reported as softening the impact of the shuttle effects. Unlike Li-ion batteries so far, no electrolyte is found to be optimal for Li–S batteries at all conditions. Taking into account all these factors, in the present study, an attempt has been made to develop solid polymer electrolytes in conjunction with non-aqueous liquid electrolytes along with inert fillers for Li–S batteries. Poly-ethylene oxide (PEO)-based composite gel polymer electrolytes (CGPE) comprising a combination of plasticizers, namely 1,3-dioxolane (DIOX)/tetraethylene glycol dimethylether (TEGDME) and a lithium salt (LiTf) with the addition of ceramic filler, barium titanate (BaTiO 3) have been prepared using a simple solution casting technique in an argon atmosphere. The as-prepared polymer electrolyte films were subjected to SEM, ionic conductivity, TG/DTA, and FTIR analyses. A symmetric cell composed of Li/CGPE/Li was assembled, and the variation of interfacial resistance as a function of time was also measured. The ionic conductivity was found to be increased as a function of temperature. The lithium transference number (Li t +) was measured, and the value was calculated as 0.7 which is sufficient for battery applications. The electrochemical stability window of the sample was studied by linear sweep voltammetry, and the polymer electrolyte film was found to be stable up to 5.7 V. The TG/DTA analysis reveals that this CGPE is thermally stable up to 350 °C. The compatibility studies exhibited that CGPE has better interracial properties with lithium metal anode. The interaction between the PEO and salt has been identified by an FTIR analysis. 相似文献
11.
Li-ion rechargeable batteries based on polymer electrolytes are of great interest for solid state electrochemical devices
nowadays. Many studies have been carried out to improve the ionic conductivity of polymer electrolytes, which include polymer
blending, incorporating plasticizers and filler additives in the electrolyte systems. This paper describes the effects of
incorporating nano-sized MnO 2 filler on the ionic conductivity enhancement of a plasticized polymer blend PMMA–PEO–LiClO 4–EC electrolyte system. The maximum conductivity achieved is within the range of 10 −3 S cm −1 by optimizing the composition of the polymers, salts, plasticizer, and filler. The temperature dependence of the polymer
conductivity obeys the VTF relationship. DSC and XRD studies are carried out to clarify the complex formation between the
polymers, salts, and plasticizer. 相似文献
12.
Development and characterisation of polyethylene oxide (PEO)-based nanocomposite polymer electrolytes comprising of (PEO-SiO 2): NH 4SCN is reported. For synthesis of the said electrolyte, polyethylene oxide has been taken as polymer host and NH 4SCN as an ionic charge supplier. Sol–gel-derived silica powder of nano dimension has been used as ceramic filler for development
of nanocomposite electrolytes. The maximum conductivity of electrolyte ∼2.0 × 10 −6 S/cm is observed for samples containing 30 wt.% silica. The temperature dependence of conductivity seems to follow an Arrhenius-type,
thermally activated process over a limited temperature range. 相似文献
13.
The electrical, structural, and photoelectrochemical properties of the polymer electrolyte PEO:NaI/I 2 doped with an ionic liquid 1-ethyl 3-methylimidazolium dicyanamide (EMImDCN) have been reported. Incorporation of the ionic
liquid (IL) increases the membrane homogeneity, decreased surface roughness, and enhances the short current ( J
sc). Additionally, the doping of IL provides more charge carriers which enhances overall ionic conductivity (σ). The optimized
σ was found at 40 wt.% IL composition. The fabricated DSSC using this new solid electrolyte showed 1.43% efficiency at 100 mW
cm −2. 相似文献
14.
Hyperbranched polymers (HBPs) with different terminal groups and different ethylene oxide (EO) chain lengths were prepared,
and the influence of the HBP structures including molecular weights and molecular weight distribution on the ionic conductivity
and the mechanical property of the composite polymer electrolytes composed of poly (ethylene oxide) (PEO), HBP, BaTiO 3 as a ceramic filler, and LiN(CF 3SO 2) 2 as a lithium salt were investigated. It was found that the molecular weights of the HBP do not affect significantly the ionic
conductivity, but the molecular weight distribution might affect it, and also further branching at the terminals of the HBP
led to a decrease in the ionic conductivity. The HBP with longer EO chain length was effective for enhancement of the ionic
conductivity in comparison with the HBP with shorter one. The increase in cross-linkable groups (acryloyl group) at the terminals
of the HBP improved the tensile strength, but caused the ionic conductivity to decrease. Loosely cross-linked composite polymer
electrolyte showed higher ionic conductivity and higher tensile strength than no cross-linked one.
Paper presented at the Patras Conference on Solid State Ionics — Transport Properties, Patras, Greece, Sept. 14 – 18, 2004. 相似文献
15.
The effects of ceramics fillers on the polymethylmethacrylate (PMMA)-based solid polymer electrolytes have been studied using
ac impedance spectroscopy and infrared spectroscopy. The polymer film samples were prepared using solution cast technique,
tetrahydrofuran (THF) used as a solvent, and ethylene carbonate (EC) has been used as plasticizer. Lithium triflate salt (LiCF 3SO 3) has been incorporated into the polymer electrolyte systems. Two types of ceramic fillers, i.e., SiO 2 and Al 2O 3, were then implemented into the polymer electrolyte systems. The solutions were stirred for several hours before it is poured
into petri dishes for drying under ambient air. After the film has formed, it was transferred into desiccator for further
drying before the test. From the observation done by impedance spectroscopy, the room temperature conductivity for the highest
conducting film from the (PMMA–EC–LiCF 3SO 3) system is 1.36 × 10 −5 S cm −1. On addition of the SiO 2 filler and Al 2O 3 filler, the conductivity are expected to increase in the order of ∼10 −4 S cm −1. Infrared spectroscopy indicates complexation between the polymer and the plasticizer, the polymer and the salts, the plasticizer
and the salts, and the polymer and the fillers. The interactions have been observed in the C=O band, C–O–C band, and the O–CH 3 band.
Paper presented at the Third International Conference on Ionic Devices (ICID 2006), Chennai, Tamilnadu, India, Dec. 7-9, 2006. 相似文献
16.
A new ion conducting solid polymer electrolyte thin film based on Polyethylene oxide (PEO) with NaClO 3 salt is prepared by solution-casting method. The solvation of salt with PEO has been confirmed by X-ray diffraction and IR
spectral studies. Plasticizer effects were studied in PEO:NaClO 3 system by using low molecular weight polyethylene glycol (PEG), dimethyl formamide (DMF) and propylene carbonate(PC). AC
conductivity in the temperature range (308–378 K) was measured to evaluate the conductivity of the polymer electrolytes. From
the conductivity data, it was found that the conductivity value of pure PEO increases 10 2–10 4 order of magnitude with the addition of salts as well as plasticizers. From the transference number experiments, it was confirmed
that the charge transport in these electrolyte is mainly due to the ions (t ion≈0.94). Finally, the conductivity value of all PEO: NaClO 3 systems were compared. 相似文献
17.
Nano-composite polymer electrolytes containing poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP), ammonium tetrafluoroborate (NH 4BF 4), and nano-size fumed silica (SiO 2) have been prepared and characterized by complex impedance spectroscopy. Ionic conductivity of polymer has been found to increase with the addition of NH 4BF 4, and a maximum conductivity of 3.62 × 10 ?6 S/cm has been obtained at 30 wt% NH 4BF 4. The formation of ion aggregates at high concentration of salt has been explained by Bjerrum’s law and mass action considerations. The conductivity of polymer electrolytes has been increased by three orders of magnitude (10 ?6 to 10 ?3 S/cm) with the addition of plasticizer, and a maximum conductivity of 1.10 × 10 ?3 S/cm has been observed at 80 wt% DMA. An increase in conductivity with the addition of nano-size fumed silica is attributed due to the formation of space-charge layers. A maximum conductivity of 7.20 × 10 ?3 S/cm has been observed for plasticized nano-composite polymer electrolytes at 3 wt% SiO 2. X-ray diffraction analysis of polymer electrolyte system was also carried out. A small change in conductivity of nano-composite polymer electrolytes observed over the 30–130 °C temperature range and for a period of 30 days is also desirable for their use in various applications. 相似文献
18.
The search for anionic conductors based on solid polymer electrolytes is important for the development of photo-electrochemical (PEC) solar cells due to their many favourable chemical and physical properties. Although solid polymer electrolytes have been extensively studied as cation, mainly lithium ion, conductors for applications in secondary batteries, their use as anionic conductors have not been studied in greater detail. In a previous paper we reported the application of a PEO based iodide ion conducting electrolyte in a PEC solar cell. This electrolyte had the composition PEO: Pr 4N +I ? = 9:1 with 50 wt.% ethylene carbonate (EC). In this work we have studied the effect of incorporating alumina filler on the properties of this electrolyte. The investigation was extended to electrical and dielectric measurements including high frequency impedance spectroscopy and thermal analysis.In the DSC themograms two endothermic peaks have been observed on heating, one of these peaks is attributed with the melting of the PEO crystallites, while the other peak with a melting temperature ~ 30 °C is attributed to the melting of the EC rich phase. The melting temperature of both these peaks shows a marked variation with alumina content in the electrolyte. The temperature dependence of the conductivity shows that there is an abrupt conductivity increase in the first heating run evidently due to the melting of the EC rich phase. High conductivity values are retained at lower temperatures in the second heating. Conductivity isotherms show the existence of two maxima, one at ~ 5% Al 2O 3 content and the other at ~ 15%. The occurrence of these two maxima has been explained in terms of the interactions caused by alumina grains, the crystallinity and melting of the PEO rich phase. As seen from latent heat of melting, the crystallinity of the electrolyte has reduced considerably during the first heating run. In contrast to the conductivity enhancement caused by ceramic fillers in PEO-based cation containing electrolytes, no conductivity enhancement has been observed in the present PEO based anionic conducting materials by adding alumina except at low temperatures. 相似文献
19.
Polymer electrolytes, which hold the key of successful operation of all solid state ionic devices, have been investigated. An amorphous polymer was used to facsimile fast ion transport in the gel polymer electrolytes (GPE) and room temperature conductivity >10 −3 S/cm can be attained. Further, these electrolytes were transformed into composites by dispersing inorganic particles of γ-Al 2O 3 (11 nm in size) in varying wt.%. An enhancement in the conductivity for an optimum concentration using LiClO 4 as a salt can be obtained and is described in terms of free charge carrier concentration, while the other family of Lithium salts viz. LiTf, LiIm, LiBETI decreases the conductivity marginally. FTIR spectroscopy supports the observed decrease in terms of more association between fillers and salts. It has been realized that the mechanical integrity of these composites increases manifold, without affecting the conductivity, significantly. 相似文献
20.
A polymer blend electrolyte based on polyvinyl alcohol (PVA) and polyacrylonitrile (PAN) was prepared by a simple solvent casting technique in different compositions. The ionic conductivity of polymer blend electrolytes was investigated by varying the PAN content in the PVA matrix. The ionic conductivity of polymer blend electrolyte increased with the increase of PAN content. The effect of lithium salt concentrations was also studied for the polymer blend electrolyte of high ionic conductivity system. A maximum ionic conductivity of 3.76×10 −3 S/cm was obtained in 3 M LiClO 4 electrolyte solution. The effect of ionic conductivity of polymer blend electrolyte was measured by varying the temperature ranging from 298 to 353 K. Linear sweep voltammetry and DC polarization studies were carried out to find out the stability and lithium transference number of the polymer blend electrolyte. Finally, a prototype cell was assembled with graphite as anode, LiMn 2O 4 as cathode, and polymer blend electrolyte as the electrolyte as well as separator, which showed good compatibility and electrochemical stability up to 4.7 V. 相似文献
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