Preparation and characterization of PVAc–PMMA-based solid polymer blend electrolytes

In the present work, a novel blend polymer electrolyte membrane using poly(vinyl acetate) (PVAc), poly(methyl methacrylate) (PMMA), and lithium per chlorate (LiClO₄) in different compositions has been prepared by the solution-casting technique. Their chemical, structural characters, thermal behavior, surface morphology, and ionic conductivity were studied using Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric/differential thermal analyzer, scanning electron microscopy, and AC impedance analyzer, respectively. A maximum ionic conductivity value of 1.67 × 10⁻⁴ S/cm at 303 K is obtained for PVAc–PMMA–LiClO₄ complexes in the ratio of 25 × 75, keeping LiClO₄ constant as 10 wt.% among all the compositions studied.     

Effect of lithium salt concentration in PVAc/PMMA-based gel polymer electrolytes

Hybrid solid polymer electrolyte films comprising of poly(vinyl acetate) (PVAc), poly(methyl methacrylate) (PMMA), LiClO₄, and propylene carbonate are prepared by solution casting technique by varying the salt concentration. In this study, PVAc/PMMA polymer blend ratio is fixed as 25:75 on the basis of conductivity and mechanical stability of the film. X-ray diffraction, Fourier transform infrared impedance, thermogravimetry/differential thermal analysis and scanning electron microscopy studies are carried out for the polymer electrolytes. The maximum ionic conductivity is found to be 4.511 × 10⁻⁴ S cm⁻¹ at 303 K for the plasticized polymer electrolyte with 8 wt.% of LiClO₄. The ionic conductivity is found to decrease with an increase of LiClO₄ concentration.     

Structural and ionic conductivity studies on P(ECH-EO):γ-BL:LiClO<Subscript>4</Subscript> plasticized polymer electrolyte

The plasticized polymer electrolyte consisting of poly(epichlorohydrin-ethyleneoxide) [P(ECH-EO)], lithium perchlorate (LiClO₄) and γ-butyrolactone (γ-BL) have been prepared by simple solution casting technique. The polymer–salt–plasticizer complex has been confirmed by XRD analysis. The ionic conductivity studies have been carried out using AC impedance technique. The effect of plasticizer (γ-BL) on ionic conductivity has been discussed with respect to different temperatures. The maximum value of ionic conductivity is found to be 1.3 × 10⁻⁴ Scm⁻¹ for 70P(ECH-EO):15γ-BL:15LiClO₄ at 303 K. The temperature dependence of the plasticized polymer electrolyte follows the Vogel–Tamman–Fulcher formalism. The activation energy is found to decrease with the increase in plasticizer.     

Electrical and structural properties of poly (ethylene oxide)/silver triflate polymer electrolyte system dispersed with MgO nanofillers

Solvent-free films of poly (ethylene oxide)–silver triflate (PEO–AgCF₃SO₃)/MgO-based nanocomposite polymer electrolytes (PEO)₅₀AgCF₃SO₃–x wt.% MgO (x = 1, 3, 5, 7, and 10) obtained using solution casting technique were found to exhibit an appreciably good complexation of MgO nanofiller within the polymer electrolyte system and non-Debye type of relaxation as revealed by Fourier transform infrared and complex impedance analyses. Optimized filler (5 wt.% MgO) when incorporated into the polymer electrolyte resulted in a maximum electrical conductivity of 2 × 10⁻⁶ S cm⁻¹ in conjunction with a silver ionic transference number (t _Ag+) of 0.23 at room temperature (298 K). Detailed structural, thermal, and surface morphological investigation indicated a slight reduction in the degree of crystallinity owing to the addition of MgO nanofiller.     

Investigation of dibutyl phthalate as plasticizer on poly(methyl methacrylate)–lithium tetraborate based polymer electrolytes

Polymer electrolyte membranes, comprising of poly(methyl methacrylate) (PMMA), lithium tetraborate (Li₂B₄O₇) as salt and dibutyl phthalate (DBP) as plasticizer were prepared using a solution casting method. The incorporation of DBP enhanced the ionic conductivity of the polymer electrolyte. The polymer electrolyte containing 70 wt.% of poly(methyl methacrylate)–lithium tetraborate and 30 wt.% of DBP presents the highest ionic conductivity of 1.58 × 10⁻⁷ S/cm. The temperature dependence of ionic conductivity study showed that these polymer electrolytes obey Vogel–Tamman–Fulcher (VTF) type behaviour. Thermogravimetric analysis (TGA) was employed to analyse the thermal stability of the polymer electrolytes. Fourier transform infrared (FTIR) studies confirmed the complexation between poly(methyl methacrylate), lithium tetraborate and DBP.     

A novel PEO-based composite polymer electrolyte with NaAlOSiO molecular sieves powders

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)₁₆LiClO₄ electrolyte. The ionic conductivity of (PEO)₁₆LiClO₄-12 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.     

Electrochemical studies on polymer electrolytes based on poly(methyl methacrylate)-grafted natural rubber for lithium polymer battery

MG30 is natural rubber grafted with 30% poly(methyl methacrylate). Gel polymer electrolytes containing MG30–LiCF₃SO₃–X (X = propylene carbonate, ethylene carbonate) are prepared by solution casting technique. The polymer–salt complexes were investigated using Fourier-transformed infrared. The ionic conductivity of the electrolytes are determined by the ac impedance studies over the temperature range of 303–383 K and is observed to obey the Vogel–Tamman–Fulcher (VTF) rule. The Li⁺ transference number obtained using the Bruce and Vincent method is <0.3. The Li/Li⁺ interface stability is established and the electrolytes were found to be able to withstand a voltage of more than 4.2 V.     

Preparation and characterizations of PVAc/P(VdF-HFP)-based polymer blend electrolytes

A novel group of polymer blend electrolytes based on the mixture of poly(vinyl acetate) (PVAc), poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP), and the lithium salt (LiClO₄) are prepared by solvent casting technique. Ionic conductivity of the polymer blend electrolytes has been investigated by varying the PVAc and PVdF-HFP content in the polymer matrix. The maximum ionic conductivity has been obtained as 0.527 × 10⁻⁴ Scm⁻¹ at 303 K for PVAc/PVdF-HFP ((25/75) wt.%)/LiClO₄ (8 wt.%). The complex formations ascertained from XRD and FTIR spectroscopic techniques and the thermal behavior of the prepared samples has been performed by DSC analysis. The surface morphology and the surface roughness are studied using SEM and AFM scanning techniques respectively.     

Morphology,chemical interaction,and conductivity of a PEO-ENR50 based on solid polymer electrolyte

A solid polymer electrolytes (SPE) comprising blend of poly(ethylene oxide; PEO) and epoxidized natural rubber as a polymer host and LiCF₃SO₃ as a dopant were prepared by solution-casting technique. The SPE films were characterized by field emission scanning electron microscopy to determine the surface morphology, X-ray diffraction, and differential scanning calorimeter to determine the crystallinity and thermogravimetric analysis to confirm the mass decrease caused by loss of the solvent. While the presence of the complexes was investigated by reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Electrochemical impedance spectroscopy was conducted to obtain ionic conductivity. Scanning electron microscopy analysis showed that a rough surface morphology of SPE became smoother with addition of salt, while ATR-FTIR spectroscopy analysis confirmed the polymer salt complex formation. The interaction occurred between the salt, and ether group of polymer host where the triple peaks of ether group in PEO merged and formed one strong peak at 1,096 cm⁻¹. Ionic conductivity was found to increase with the increase of salt concentration in the polymer blend complexes. The highest conductivity achieved was 1.4 × 10⁻⁴ Scm⁻¹ at 20 wt.% of LiCF₃SO₃, and this composition exhibited an Arrhenius-like behavior with the activation energy of 0.42 eV and the preexponential factor of 1.6 × 10³ Scm⁻¹.     

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.     

Structural,thermal and ion transport studies on nanocomposite polymer electrolyte-{(PEO + SiO<Subscript>2</Subscript>):NH<Subscript>4</Subscript>SCN} system

Development and characterisation of polyethylene oxide (PEO)-based nanocomposite polymer electrolytes comprising of (PEO-SiO₂): NH₄SCN is reported. For synthesis of the said electrolyte, polyethylene oxide has been taken as polymer host and NH₄SCN 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.     

Effects of MnO<Subscript>2</Subscript> nano-particles on the conductivity of PMMA-PEO-LiClO<Subscript>4</Subscript>-EC polymer electrolytes

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 MnO₂ filler on the ionic conductivity enhancement of a plasticized polymer blend PMMA–PEO–LiClO₄–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.     

Impedance and FTIR studies on plasticized PMMA–LiN(CF<Subscript>3</Subscript>SO<Subscript>2</Subscript>)<Subscript>2</Subscript> nanocomposite polymer electrolytes

Plasticized polymer electrolytes composed of poly(methyl methacrylate) (PMMA) as the host polymer and lithium bis(trifluoromethanesulfonyl)imide LiN(CF₃SO₂)₂ as a salt were prepared by solution casting technique at different ratios. The ionic conductivity varied slightly and exhibited a maximum value of 3.65 × 10⁻⁵ S cm⁻¹ at 85% PMMA and 15% LiN(CF₃SO₂)₂. The complexation effect of salt was investigated using FTIR. It showed some simple overlapping and shift in peaks between PMMA and LiN(CF₃SO₂)₂ salt in the polymer electrolyte. Ethylene carbonate (EC) and propylene carbonate (PC) were added to the PMMA–LiN(CF₃SO₂)₂ polymer electrolyte as plasticizer to enhance the conductivity. The highest conductivities obtained were 1.28 × 10⁻⁴ S cm⁻¹ and 2.00 × 10⁻⁴ S cm⁻¹ for EC and PC mixture system, respectively. In addition, to improve the handling of films, 1% to 5% fumed silica was added to the PMMA–LiN(CF₃SO₂)₂–EC–PC solid polymer electrolyte which showed a maximum value at 6.11 × 10⁻⁵ S cm⁻¹ for 2% SiO₂.     

Ionic conduction behavior in PVC–PEG blend polymer electrolytes upon the addition of TiO2

The blend-based polymer electrolyte consisting of poly (vinyl chloride) (PVC) and poly (ethylene glycol) (PEG) as host polymers and lithium perchlorate (LiClO₄) as the complexing salt was studied. An attempt was made to investigate the effect of TiO₂ concentration in the unplasticized PVC–PEG polymer electrolyte system. The XRD and FTIR studies confirm the formation of a polymer–salt complex. The conductivity results indicate that the incorporation of ceramic filler up to a certain concentration (15 wt.%) increases the ionic conductivity and upon further addition the conductivity decreases. The maximum ionic conductivity 0.012 × 10⁻⁴ S cm⁻¹ is obtained for PVC–PEG–LiClO₄–TiO₂ (75–25–5–15) system. Thermal stability of the polymer electrolyte is ascertained from TG/DTA studies.     

Preparation and characterization of polyindole–ZnO composite polymer electrolyte with LiClO<Subscript>4</Subscript>

This paper describes the preparation and conductivity studies of polyindole–ZnO composite polymer electrolyte (CPE) with LiClO₄. Polyindole–ZnO-based polymer nanocomposites were prepared by chemical method and characterized by XRD, infrared (IR), scanning electron microscope (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The IR spectrum confirms the intermolecular interaction between polyindole and ZnO. The significant spectral changes of polyindole and ZnO nancomposites reveal the strong interaction between polyindole and ZnO nanoparticles. The structural morphologies of the ZnO, polyindole, and polyindole–ZnO are obtained from SEM. The TEM image of polyindole nanocomposite shows that ZnO is embedded in polyindole matrix. An enhanced conductivity of 4.405 × 10⁻⁷ S cm⁻¹ at 50 °C for the CPE was determined from impedance studies.     

Effect of ethylene carbonate plasticizer and TiO<Subscript>2</Subscript> nanoparticles on 49% poly(methyl methacrylate) grafted natural rubber-based polymer electrolyte

The effect of plasticizer and TiO₂ nanoparticles on the conductivity, chemical interaction and surface morphology of polymer electrolyte of MG49–EC–LiClO₄–TiO₂ has been investigated. The electrolyte films were successfully prepared by solution casting technique. The ceramic filler, TiO₂, was synthesized in situ by sol-gel process and was added into the MG49–EC–LiClO₄ electrolyte system. Alternating current electrochemical impedance spectroscopy was employed to investigate the ionic conductivity of the electrolyte films at 25 °C, and the analysis showed that the addition of TiO₂ filler and ethylene carbonate (EC) plasticizer has increased the ionic conductivity of the electrolyte up to its optimum level. The highest conductivity of 1.1 × 10⁻³ Scm⁻¹ was obtained at 30 wt.% of EC. Fourier transform infrared spectroscopy measurement was employed to study the interactions between lithium ions and oxygen atoms that occurred at carbonyl (C=O) and ether (C-O-C) groups. The scanning electron microscopy micrograph shows that the electrolyte with 30 wt.% EC posses the smoothest surface for which the highest conductivity was obtained.     

Measurement of ionic conductivity of poly (<Emphasis Type="Italic">N</Emphasis>-vinylimidazole) and its fluoroborate salt in solid state

The conductivity of poly(N-vinylimidazole) (PVIM) and its fluoroborate salt (PVIM–HBF₄) are reported here. N-vinylimidazole is polymerized by free radical method and PVIM–HBF₄ is prepared by acidification of PVIM with HBF₄. The polyelectrolyte so formed has been characterized by infrared, hydrogen-1 nuclear magnetic resonance, thermogravimetric analyzer, and differential scanning calorimetry. Frequency and temperature dependence of AC conductivity has been studied to learn about the electrical conduction behavior in the materials. The electrical conductivity of the new material is found to be in the range of 10⁻⁵ to 10⁻⁶ S cm⁻¹.There is about 10²- to 10³-fold increase in conductivity of the polyelectrolyte. The material is shown to be a predominantly ionic conductor with t _ion ≈ 0.88. Apparent activation energies are found to be 0.397 and 0.250 eV for the polymer and the polyelectrolyte, respectively.     

Li ion conduction on plasticizer-added PVAc-based hybrid polymer electrolytes

Poly(vinyl acetate), poly(vinylidene fluoride–hexafluoropropylene), lithium perchlorate salt, and the different plasticizer-based gel polymer electrolytes were prepared by solvent-casting technique. The structural and the complex formation have been confirmed by X-ray diffraction spectroscopic analysis. Thermal stability of the different plasticizer-added electrolyte films has been analyzed by means of thermogravimetric analysis. Ionic conductivity of the electrolyte samples has been found as a function of temperature and the plasticizers. Among the various plasticizers, ethylene carbonate-based complexes exhibit maximum ionic conductivity value of the order of 10⁻⁴ Scm⁻¹. Finally, the microstructure of the maximum ionic conductivity sample has been depicted with the help of scanning electron microscope analysis.     

Structural and ionic conductivity studies on proton conducting polymer electrolyte based on polyvinyl alcohol

An attempt has been made to prepare a new proton conducting polymer electrolyte based on polyvinyl alcohol (PVA) doped with NH₄NO₃ by solution casting technique. The complex formation between polymer and dissociated salt has been confirmed by X-ray diffraction analysis. The ionic conductivity of the prepared polymer electrolyte has been found by ac impedance spectroscopic analysis. The highest ionic conductivity has been found to be 7.5 × 10⁻³ Scm⁻¹ at ambient temperature for 20 mol% NH₄NO₃-doped PVA with low activation energy (~0.19 eV). The temperature-dependent conductivity of the polymer electrolyte follows an Arrhenius relationship, which shows hopping of ions in the polymer matrix.     

The effect of hard segment content on ionic conductivity of poly(ether urethane)-based solid polymer electrolytes

To investigate the effect of hard segment content on ionic conductivities of poly(ether urethane) (PEU)-based solid polymer electrolytes (SPEs), PEUs containing 20, 40, 60, 80, and 100 wt.% of hard segment content were synthesized. Also we introduced polymer-in-salt system with ion-hopping mechanism contrary to traditional salt-in-polymer system with segmental motion mechanism and investigated the effect of hard segment of PEU on ionic conductivities by A.C. impedance, FT-IR, DSC, and SEM. And it could be known that hydrogen bonding of urethane group influenced the ionic conductivities of PEU-based SPE. PEU-based SPE containing 70 wt.% of salt and 20 wt.% of hard segment showed the highest ionic conductivity of 2.95 × 10⁻⁵ S/cm at room temperature.