Nanocomposite Solid Polymer Electrolytes Research Articles

Mathematical modeling of field-assisted Li ion conduction in nanocomposite solid polymer electrolyte systems

Nanocomposite solid polymer electrolyte films were prepared to study the effect of electric field on the ionic conductivity. The studies were carried out by varying the electric field from 0 to 100 V cm−1 at different temperatures and the results shows that conductivity increases with increase in electric field and temperature. A mathematical model is proposed to describe the electric field and temperature-dependent ionic conductivity in nanocomposite solid polymer electrolyte systems. The correlation between the proposed equation and the experimental observations showed high degree of correlation.

Effect of TiO2 nanoparticles on structural, thermal, mechanical and ionic conductivity studies of PEO12–LiTDI solid polymer electrolyte

In the present study, poly(ethylene oxide) (PEO) complexed with lithium 2-trifluoromethyl-4,5-dicyanoimidazole (LiTDI) nanocomposite solid polymer electrolyte membranes (NSPEMs) have been prepared by solution cast technique using different weight percent of nano-sized TiO2 ceramic filler. The effect of filler incorporation on the structural, thermal, mechanical and ionic conductivity properties of solid polymer electrolytes have analyzed. X-ray diffraction (XRD) and polarized optical microscopy (POM) results indicated that the crystallinity has been reduced remarkably with the incorporation of TiO2 nanofiller. The thermal stability and mechanical integrity of the nanocomposite polymer electrolyte system increased significantly compared to filler free electrolytes. The maximum ionic conductivity is found to be in the range of 2.11×10−5Scm−1 for 8wt% TiO2 nanofiller in PEO12–LiTDI electrolyte system. These results indicated that the prepared TiO2 based nanocomposite membrane would be a promising alternative separator for rechargeable lithium-ion battery applications.

Nano composite solid polymer electrolytes based on biodegradable polymers starch and poly vinyl alcohol

An attempt has been made to prepare nano composite solid polymer electrolytes by adding nano fumed silica in different weight ratios in a polymer matrix composed of biodegradable polymers Starch and Poly Vinyl Alcohol (PVA) to get high ionic conductivity with good mechanical strength. Fourier Transform InfraRed spectroscopy (FTIR) was used to confirm the complexation and interaction of the nano filler with the polymer matrix. From the FTIR investigations it could be established that the formation of COSi bonds by nano fumed SiO2 with Starch and PVA lead to the crucial structural modification that finally increase the conductivity of the sample. Dielectric and frequency dependent measurements substantiate the sharp increase in number of charge carriers as the major factor contributing to the enhancement of the conductivity for 3wt% nano fumed silica. Electric modulus studies confirmed the ionic nature and indicate absence of electrode polarization in the system. Maximum ionic conductivity ∼10−3S/cm could be realized for 3wt% silica at ambient condition.

Role of Dielectric Constant on Ion Transport: Reformulated Arrhenius Equation

Solid and nanocomposite polymer electrolytes based on chitosan have been prepared by solution cast technique. The XRD results reveal the occurrence of complexation between chitosan (CS) and the LiTf salt. The deconvolution of the diffractogram of nanocomposite solid polymer electrolytes demonstrates the increase of amorphous domain with increasing alumina content up to 4 wt.%. Further incorporation of alumina nanoparticles (6 to 10 wt.% Al2O3) results in crystallinity increase (large crystallite size). The morphological (SEM and EDX) analysis well supported the XRD results. Similar trends of DC conductivity and dielectric constant with Al2O3concentration were explained. The TEM images were used to explain the phenomena of space charge and blocking effects. The reformulated Arrhenius equation (σ(ε′,T)=σoexp(-Ea/KBε′T)) was proposed from the smooth exponential behavior of DC conductivity versus dielectric constant at different temperatures. The more linear behavior of DC conductivity versus1000/(ɛ′×T)reveals the crucial role of dielectric constant in Arrhenius equation. The drawbacks of Arrhenius equation can be understood from the less linear behavior of DC conductivity versus1000/T. The relaxation processes have been interpreted in terms of Argand plots.

PEO nanocomposite polymer electrolyte for solid state symmetric capacitors

Physical and electrochemical properties of polyethylene oxide (PEO)-based nanocomposite solid polymer electrolytes (NPEs) were investigated for symmetric capacitor applications. Nanosize fillers, i.e., Al2O3 and SiO2 incorporated polymer electrolyte exhibited higher ionic conductivity than those with filler-free composites. The composites have been synthesized by the completely dry (solution-free) hot-press method. The addition of filler in fractional amount to the solid polymer matrix at room temperature further enhances the ionic conductivity. Nature of the NPEs were studied using X-ray diffraction and energy-dispersive spectra analyses. Thermal stability of the resulting electrolyte was analysed by thermogravimetric analysis and differential scanning calorimetric studies. Morphology changes occurred during the addition of fillers was evidenced by scanning electronic microscope images. Solid polymer electrolytes exhibiting these parameters was found to be suitable for solid state capacitors. The results obtained from the electrolytes with an optimum compositions (PEO70AgI30)93(Al2O3)7 and (PEO70AgI30)95(SiO2)5 used in the (PEO70AgI30)70(AC)30 electrodes for symmetric capacitor applications and their performances were analysed by impedance spectroscopic, Bode plot, cyclic voltammetry, discharge characteristics and leakage current profile.

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

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

Nanocomposite solid polymer electrolytes based on poly(ethylene oxide)/POSS-PEG (n = 13.3) hybrid nanoparticles for lithium ion batteries

We successfully prepared the nanocomposite solid polymer electrolytes based on poly(ethylene oxide) (PEO)/polyhedral oligomeric silsesquioxane-polyethylene glycol (POSS-PEG) complexed with LiN(SO2CF3)2 (LiTFSI) salt and studied the effect of POSS-PEG (n=13.3) hybrid nanoparticles on structural, thermal, mechanical and ionic conductivity properties. The crystallinity of the nanocomposite solid polymer electrolytes has been characterized by X-ray diffraction (XRD). FTIR studies showed the evidence of the complexation between PEO, LiTFSI and POSS-PEG. Differential scanning calorimetry (DSC) was used to study their glass transition and melting behaviors and to measure their respective degrees of crystallinity. The degree of crystallinity reduced with POSS-PEG content, indicating restricted segmental motion of the polymer chains. The Young's modulus increased from 0.076 to 0.19MPa with the addition of POSS-PEG. Ionic conductivity studies reveal that solid polymer electrolyte with 30wt% of POSS-PEG has the highest ionic conductivity of 5.05×10−5S/cm at room temperature (23°C). The temperature dependence conductivity studies showed that the samples seemed to obey the Arrhenius behavior.

Nanocomposite solid polymer electrolytes based on polyethylene oxide, modified nanoclay, and tetraethylammonium tetrafluoroborate for application in solid‐state supercapacitor

Nanocomposite solid polymer electrolytes (SPEs) have been prepared from polyethylene oxide (PEO), organically modified nanoclay (MNclay), and tetraethylammonium tetrafluoroborate (TEABF4) salt. The concentration of the salt has been varied in the respective SPE, wherein PEO/MNclay ratio was kept constant. It has been proposed that three types of complex formation could be operative in the SPEs due to the interactions among PEO, MNclay, and the salt. The complex formation mechanism has been postulated on the basis of X‐ray diffraction (XRD) analysis, transmission electron microscopic (TEM) observation, differential scanning calorimetric (DSC) analysis, and polarized optical microscopic (POM) observation. ‘Complex 1’ and ‘complex 3’ formation could be involved in the crystalline phase as indicated by DSC and XRD analyses, whereas ‘complex 2’ formation might be restricted in the amorphous phase as suggested by TEM observation. The ionic conductivity of the SPEs has been correlated with the results obtained from XRD, DSC, and POM analyses. The formation of complex 1 and complex 2 could be responsible for the increase in the ionic conductivity, whereas complex 3 formation might decrease the ionic conductivity. An activated carbon‐based supercapacitor has been fabricated using SPEs and characterized by cyclic voltammetry, galvanostatic ‘charge–discharge’ behavior, and impedance spectroscopic analysis. POLYM. ENG. SCI., 55:1536–1545, 2015. © 2015 Society of Plastics Engineers

One-pot synthesis nano-hybrid ZrO2–TiO2 fillers in 49% poly(methyl methacrylate) grafted natural rubber (MG49) based nano-composite polymer electrolyte for lithium ion battery application

Initial investigations on ionic conductivity properties, morphology studies and chemical interactions of new nano-composite solid polymer electrolyte (NCPE) of MG49–LiCF3SO3 (20wt.%)–ZrO2–TiO2 (ratio of 1:1) were conducted by means of one-pot synthesis in different pH media for application in the electrochemical device system. Synthesis hybrid oxides of ZrO2–TiO2 were done using the in-situ sol–gel method inside dissolved grafted natural rubber polymer MG49 which act as polymer electrolyte host. The solid polymer electrolyte film was obtained via the solution casting method. Analysis impedance showed that highest ionic conductivity was obtained at 1.20×10−5Scm−1 in acidic medium and temperature dependence ionic conductivity has been studied based on Arrhenius plot. Analysis XRD revealed that crystalline phase of the electrolyte systems was reduced with addition of acid or base. No lithium salt crystalline peaks were observed indicating that the doped lithium salt was well dissociated throughout the electrolyte systems. FTIR results showed that the pH of the mediums affects the formation of zirconia–titania particles at carbonyl and ether groups of the polymer. It also reflects the chemical stability of acid-base towards polymer electrolyte. Analysis of FESEM confirmed the formation of zirconia and titania particles at size range of 8–15nm. Charge–discharge study showed a high discharge capacity and columbic efficiency of 97.6%.

Ion‐transport study in nanocomposite solid polymer electrolytes based on chitosan: Electrical and dielectric analysis

ABSTRACTIn this study, (1.1111 − x)(0.9CS–0.1NaTf)xAl2O3(0.02 ≤ x ≤ 0.1) [where CS is chitosan, NaTf is sodium triflate (NaCF3SO3), and Al2O3 is aluminum oxide] nanocomposite solid polymer electrolyte (SPE) films based on CS were prepared by a solution casting technique. X‐ray diffraction and scanning electron microscopy analysis revealed that the alumina nanoparticles had a great effect on the structural and morphological behavior of the CS–NaTf (90:10) polymer electrolyte. An investigation of the electrical and dielectric parameters of the nanocomposite SPE films was conducted. Electrical impedance spectroscopy was carried out for this purpose. The relationships between the electrical and dielectric parameters were used to interpret and understand the ion‐conduction mechanism. We observed that the direct‐current conductivity (σdc) and dielectric constant followed the same trend with salt concentration. σdc versus temperature showed the Arrhenius and Vogel‐Fulcher‐Tammann (VTF) regions. The drops of σdc at high temperatures were observed for all of the samples. The ion relaxation dynamics were studied from Argand plots. For the first time, we confirmed the existence of a strong experimental relationship between the high‐frequency semicircle of the impedance plots and the high‐frequency dispersion regions of the alternating‐current conductivity (σac). The dispersion regions of σac were used to study the ion‐conduction mechanism. The behavior of the frequency exponent as a function of the temperature was used to interpret σdc versus the temperature. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41774.

Dielectric Relaxation Study on TiO<sub>2</sub> Based Nanocomposite Blend Polymer Electrolytes

Nanocomposite solid polymer electrolytes comprise of PMMA (poly methyl methacrylate), PVP (poly vinyl pyrolidone), MSA (methanesulfonic acid) and TiO2 as nanofiller were prepared by solution casting technique at different compositions. Sample with 1 mol% incorporated TiO2 has shown maximum conductivity and its value was found as 2.82 ×10-5 S/cm. The value of conductivity has been enhanced to about 31% upon the addition of nanofiller. The relaxation time for all the prepared composites as well as for the composite having maximum conductivity at various isotherms have been calculated from the loss tangent plot. The frequency and temperature dependence of dielectric constant and dielectric loss nanocomposite solid polymer electrolytes have also been studied. The modulus analysis confirms the non-Debye type formalism in the prepared composites.

Structural, thermal, electrical, and dielectric properties of synthesized nanocomposite solid polymer electrolytes

In the present article, polyvinyl alcohol (PVA) polymer, sodium iodide (NaI) salt, and fumed silica nanoparticles nanofiller have been used for the preparation of solid polymer electrolyte films. Fourier transform infrared spectroscopy has been performed to study the vibrational change due to the complexation among polymer, salt, and nanofiller. X-Ray diffraction has been carried out to study the structural changes in the PVA:NaI (60:40) polymer electrolyte films with fumed silica nanoparticles as dopant. Differential scanning calorimetry studies show decreasing trend in the glass transition temperature for nanocomposite polymer electrolyte films. Thermogravimetric analysis has been performed to study the thermal degradation of the sample. Determination of transference number using Wagner’s polarization technique indicates that the ions are the dominant mobile species. Maximum conductivity of approximately 3.8 × 10−3 S cm−1 at room temperature has been estimated for PVA:NaI (60:40) film containing 0.5% fumed silica nanoparticles with low value of activation energy. Dielectric relaxation studies with temperature show shifts of the relaxation time toward higher value for samples of nanocomposite polymer electrolyte films.

Studies on the Influence of Titania Content on the Properties of Poly(vinyl chloride) - Poly (acrylonitrile)-Based Polymer Electrolytes

Nanocomposite solid polymer electrolytes were developed from the matrix of poly (vinyl chloride) (PVC), poly (acrylonitrile) (PAN), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and titania (TiO2) by solution-casting method. An appropriate addition of TiO2 content in the matrix enhances the ionic conductivity significantly, as being viewed, the highest ionic conductivity of 6.48 × 10−4 S cm−1 was achieved upon addition of 3 wt.% of TiO2. The presence of 3 wt.% TiO2 tailors the insulating properties of the blended PVC-PAN and greatly increases the matrix amorphous structure, permitting greater ionic transport and hence improves the conducting nature. The increase in the structural disorderliness occurs upon greater interaction between PVC-PAN: LiTFSI and TiO2. The ionic conductivity-temperature plots show that the conductivity enhancement is thermally assisted through the frequent hopping of cations to the neighboring vacant site, which follows Arrhenius behavior. The occurrence of material electrode interface polarization process and presence of dipoles were understood from the permittivity study and through the appearance of tangent loss peaks in all the tested samples respectively. The electrical modulus studies were also done to investigate the ionic relaxation processes in the composites in term of conductivity relaxation time.

Effect of ZnO filler concentration on the conductivity, structure and morphology of PVdF-HFP nanocomposite solid polymer electrolyte for lithium battery application

The polyvinylidene difluoride-co-hexafluoropropylene (PVdF-HFP) nanocomposite solid polymer electrolyte films were developed by solution-casting method. PVdF-HFP as a polymer host, lithium perchlorate (LiClO4) as a salt for lithium ion, and ZnO nanoparticles as fillers were used to form the nanocomposite solid polymer electrolyte films. All the prepared samples were characterized by X-ray diffraction (XRD), differential scanning calorimetry, and scanning electron microscopy. The XRD patterns of the pure and nanocomposite solid polymer electrolyte samples indicate the formation of amorphous phase with 17.5 wt.% of lithium salt and ZnO fillers up to 3 wt.%. The total conductivity and lithium ion transference number were studied at room temperature by using impedance spectroscopy and Wagner’s polarization methods. The highest conductivity at room temperature for solid polymer electrolyte and nanocomposite solid polymer electrolyte are found to be 3.208 × 10−4 and 1.043 × 10−3 S/cm, respectively. Similarly, the lithium ion transference number is evaluated for the optimized solid polymer electrolyte and nanocomposite solid polymer electrolyte films with 3 wt.% of ZnO fillers. And it is found that ionic transference number could be enhanced from 92 to 95 % with the addition of nanosized ZnO fillers to the solid polymer electrolyte.

Fabrication of Li-polymer/silica aerogel nanocomposite electrolyte for an all-solid-state lithium battery

Abstract Nanocomposite solid-polymer electrolytes were fabricated using polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), LiClO 4 and silica aerogel, with the aim of improving lithium ion conductivity and thermal stability. The effects of the PEO:PVDF ratio, polymer:Li-salt ratio, and silica aerogel content on the electrical conductivity of the solid-polymer electrolytes were examined. Highest lithium ion conductivity of 1.70×10 −4 S/cm was obtained at 30 °C in the SPE-2 sample with PEO:PVDF=3:1 and polymer:Li-salt=6:1. XRD and FT-IR analysis showed that the observed phenomenon could be explained by the degree of crystallinity of the polymer electrolyte and by the dissociation degree of Li-salt.

Effect of succinonitrile and nano-hydroxyapatite on ionic conductivity and interfacial stability of polyether-based plasticized nanocomposite polymer electrolytes (PNCSPE)

A series of novel plasticized nanocomposite solid polymer electrolytes (PNCSPE) consisting of polyethylene oxide as polymer host, lithium bisoxalatoborate as salt with different weight ratios of succinonitrile and nano-hydroxyapatite was prepared by membrane hot-press technique. The electrical property of PNCSPE was investigated by AC impedance analysis. The migration of lithium ion in the polymer matrix was confirmed from cyclic voltammetry study. The incorporation of different compositions of filler and plasticizer in the polymer matrix significantly enhanced the amorphous nature resulted in increase in ionic conductivity of PNCSPE. The maximum ionic conductivity was found to be in the order of 10−3.1 S/cm.

Electrical and Dielectric Behavior of Nano-bio Ceramic Filler Incorporated Polymer Electrolytes for Rechargeable Lithium Batteries

A series of nanocomposite solid polymer electrolytes (NCSPE) consisting of PMMA as host polymer, lithium bisoxalatoborate (LiBOB) as doping salt and nano-hydroxy apatite as filler have prepared by membrane hot-press method. To enhance the electrochemical properties and stiffness of polymer electrolyte film, a bioactive ceramic filler nano-hydroxy apatite is incorporated in the polymer matrix. The prepared different weight contents of NCSPE films are subjected to various electrochemical characterizations such as ionic conductivity, electric modulus and dielectric spectroscopy studies. The complexation behavior and structural reorganization in polymer electrolytes are confirmed by means of FT-IR (Fourier-Transform Infra Red Spectroscopy) analysis. The electrical response and relaxation of dipole in polymer electrolytes are investigated by means of electric modulus and dielectric studies. The addition of nano-hydroxy apatite significantly enhances the ionic conductivity and blocking the reorganizing tendency of polymer matrix. The maximum ionic conductivity is found to be in the range of 10-4.8 S/cm for sample containing 10 wt. % nanoceramic filler.

Effect of Chitin Nanofibres on the Electrochemical and Interfacial Properties of Composite Solid Polymer Electrolytes

Chitin nanofibres (CNF) are synthesized from a biopolymer chitin by ultra-pure chemical curing method. The nanocomposite solid polymer electrolytes (CSPE) based on PEO-LiBOB with chitin nanofibres as inert nanofiller are prepared by membrane hot-press method. The polymer membrane obtained is subjected to various electrochemical studies such as impedance analysis, cyclic voltammetry and compatibility studies. The crystalline behavior and structural changes in CSPE are investigated by means of XRD and FT-IR analyzes. The filler incorporated membrane shows better electrochemical properties as compared to filler free membrane. The addition of chitin nanofibre in polymer matrix enhances the ionic conductivity and achieves a maximum of 10-3.8 S/cm. Cyclic voltammetry study is used to know the electrochemical activity of prepared polymer electrolytes at ambient temperature. The compatibility studies reveals that the filler incorporated nanocomposite solid polymer electrolytes reduce the value of interfacial resistance (Ri) and it is better compatible with lithium interface.

Role of silica nanoparticles in conductivity enhancement of nanocomposite solid polymer electrolytes: (PEGx NaBr): ySiO2

Nanocomposite solid polymer electrolytes (NCSPEs) with conducting species other than Li ions are being investigated for solid-state battery applications. Pristine solid polymer electrolytes (SPEs) do not show ionic conductivity suitable for batteries. Addition of inert fillers to SPEs is known to enhance the ionic conductivity. In this paper, we present the role of silica nanoparticles in enhancing the ionic conductivity in NCSPEs with sodium as conducting species. Sodium bromide is complexed with the host polyethylene glycol polymer by solution cast method and silica nanoparticles (SiO2, average particle size 7 nm) are incorporated into the complex in small amounts. The composites are characterized by powder XRD and IR spectroscopy. Conductivity measurements are undertaken as a function of concentration of salt and also as a function of temperature using impedance spectroscopy. Addition of silica nanoparticles shows an enhancement in conductivity by 1–2 orders of magnitude. The results are discussed in terms of interaction of nanoparticles with the nonconducting anions.

Ionic conductivity enhancement in the solid polymer electrolyte PEO9LiTf by nanosilica filler from rice husk ash

Rice husk ash is a cheap raw material available in abundance in rice-growing countries. It contains around 85–90 % amorphous silica. Rice husk ash, when subjected to a simple chemical precipitation method, will produce nanosilica which can be used for many industrial and technological applications. In this work, we have successfully synthesized nano-sized silica from local rice husk ash and prepared the nanocomposite solid polymer electrolyte, PEO9LiTf:SiO2. The resulting electrolyte has been characterized by X-ray diffraction, differential scanning calorimetry, atomic force microscopy, Fourier transform infrared spectroscopy, and complex impedance spectroscopy. The electrolyte shows about a 12-fold increase in ionic conductivity at room temperature due to the silica filler. In the nanocomposite electrolyte, nanosilica particles obtained from rice husk ash behaved very similarly to the commercial grade nanosilica and had a size distribution in the 25- to 40-nm range. As already suggested by us and by others, the O2− and OH− surface groups in the filler surface interact with the Li+ ions and provide hopping sites for migrating Li+ ions through transient H bonding, creating additional high-conducting pathways. This would contribute to a substantial conductivity enhancement through increased ionic mobility. An additional contribution to conductivity enhancement, particularly at temperatures below 60 °C, appears to come from the increased fraction of the amorphous phase, as evidenced from the reduced crystallite melting temperature and the reduced enthalpy of melting due to the presence of the filler.