Conductivity study of polyethylene oxide (PEO) complexed with sodium bicarbonate

Ion conducting thin film polymer electrolytes based on polyethylene oxide (PEO) complexed with NaHCO₃ salt has been prepared using solution-cast technique. The complexation of NaHCO₃ salt with PEO is confirmed by XRD and IR studies. DC conductivity in the temperature range 303–368 K has been evaluated. The conductivity is found to increase in the PEO complex with the NaHCO₃ salt and also with an increase in temperature. Using this polymer electrolyte, an electrochemical cell with the configuration Na/(PEO + NaHCO₃)/(I₂ + C + electrolyte) has been fabricated and its discharge characteristics studied. Open Circuit Voltage (OCV) and Short Circuit Current (SCC) are found to be 2.69 V and 1.28 mA, respectively. Other parameters associated with the cell are evaluated and presented in this paper.     

Ion transport and electrochemical cell characteristic studies of a new (PVP 1 NaNO3) polymer electrolyte system

Polymer electrolyte films based on poly (vinyl pyrrolidone) (PVP) complexed with NaNO₃ salt have been prepared by solution—cast technique. Several experimental techniques such as X-ray diffraction, Infrared (IR), DC—electrical conductivity, transference number measurements have been employed to characterize the polymer electrolyte. The conductivity of the (PVP + NaNO₃) electrolyte is about 10⁴ times larger than that of pure PVP at room temperature. The transference number measurements show that the charge transport in this polymer electrolyte system is predominantly due to ions. Using this polymer electrolyte, an electrochemical cell with the configuration Na/(PVP + NaNO₃)/(I₂ + C + electrolyte) has been fabricated and its discharge characteristics studied. The open circuit voltage (OCV) and short circuit current (SCC) observed for the cell are 2.65 V and 1.1 mA respectively. A number of other cell parameters evaluated are also reported.     

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

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

Influence of 1-ethyl-3-methylimidazolium bis (trifluoromethyl sulfonyl) imide plasticization on zinc-ion conducting PEO/PVdF blend gel polymer electrolyte

The influence in terms of plasticizer on zinc-ion conducting polymer blend electrolyte system, [PEO (90 wt%)/PVdF (10 wt%)]-15 wt% Zn (CF₃SO₃)₂] with various concentrations of 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (EMIMTFSI) was investigated. The freshly-prepared thin films of [PEO (90 wt%)/PVdF (10 wt%)]-15 wt% Zn (CF₃SO₃)₂)?+?x wt% EMIMTFSI, where x?=?1, 3, 5, 7, and 10 wt%] were characterized by means of X-ray diffraction (XRD), Fourier transformed infrared (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and impedance analysis techniques. The room temperature XRD patterns tend to support the enhanced amorphous phase as a result of deducing the degree of crystallinity of the polymer blend–salt system by the addition of 7 wt% EMIMTFSI. The relevant SEM images of 7 wt% EMIMTFSI incorporated gel polymer electrolyte exhibit a minimised spheurilite structure when compared to that of the polymer blend–salt system. Unusually, the highest ionic conductivity realized in the case of the typical gel polymer electrolyte system, [PEO/PVdF-Zn (CF₃SO₃)₂ + 7 wt% EMIMTFSI] is found to be 1.63?×?10^?4 S cm^?1 at room temperature. The temperature dependence of conductivity has been examined based on the Vogel–Tammann–Fulcher (VTF) equation, thereby suggesting the segmental chain motion and free volume changes. The occurrence of ion dynamics and dielectric relaxation behaviour in the chosen system has been analysed in a detailed fashion at room temperature using frequency response impedance formalisms involving electric modulus and dielectric permittivity features.     

Lithium ion conducting solid polymer blend electrolyte based on bio-degradable polymers

Lithium ion conducting polymer blend electrolyte films based on poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) with different Mwt% of lithium nitrate (LiNO₃) salt, using a solution cast technique, have been prepared. The polymer blend electrolyte has been characterized by XRD, FTIR, DSC and impedance analyses. The XRD study reveals the amorphous nature of the polymer electrolyte. The FTIR study confirms the complex formation between the polymer and salt. The shifts in T _g values of 70 PVA–30 PVP blend and 70 PVA–30 PVP with different Mwt% of LiNO₃ electrolytes shown by DSC thermograms indicate an interaction between the polymer and the salt. The dependence of T _g and conductivity upon salt concentration has been discussed. The ion conductivity of the prepared polymer electrolyte has been found by a.c. impedance spectroscopic analysis. The PVA–PVP blend system with a composition of 70 wt% PVA: 30 wt% PVP exhibits the highest conductivity of 1·58 × 10^???6 Scm^???1 at room temperature. Polymer samples of 70 wt% PVA–30 wt% PVP blend with different molecular weight percentage of lithium nitrate with DMSO as solvent have been prepared and studied. High conductivity of 6·828 × 10^???4 Scm^???1 has been observed for the composition of 70 PVA:30 PVP:25 Mwt% of LiNO₃ with low activation energy 0·2673 eV. The conductivity is found to increase with increase in temperature. The temperature dependent conductivity of the polymer electrolyte follows the Arrhenius relationship which shows hopping of ions in the polymer matrix. The relaxation parameters (ω) and (τ) of the complexes have been calculated by using loss tangent spectra. The mechanical properties of polymer blend electrolyte such as tensile strength, elongation and degree of swelling have been measured and the results are presented.     

SAXS/WAXS/DSC study of temperature evolution in nanopolymer electrolyte

Soft matter polymer electrolytes as nanostructured materials are very attractive components for batteries and for opto-electronic devices as a new generation of dye-sensitized solar cells. (PEO)₈ZnCl₂ polymer electrolytes were prepared from PEO and ZnCl₂. The nanocomposites (PEO)₈ZnCl₂/TiO₂ themselves contained TiO₂ nanograins. In this work, the influence of TiO₂ nanograins or the morphology and ionic conductivity of the nanocomposite was systematically studied by small-angle X-ray scattering (SAXS) simultaneously recorded with wide-angle X-ray scattering (WAXS) and differential scanning calorimetry (DSC) at the synchrotron ELETTRA. Shown by previous impedance spectroscopy measurements (IS), the room temperature conductivity of nanocomposite polymer electrolyte increased more than two times above 65 °C, relative to pure composites of PEO and salts. The SAXS/DSC measurements yielded insight into the temperature-dependent changes of the grains of the electrolyte as well as into the effects of heating and cooling rates. The crystal structure and temperatures of melting and crystallization of the nanosize grains was revealed by the simultaneous WAXS measurements.     

Structural,electrical and electrochemical parameters of PEO–NaClO3 composite for battery applications

Polyethylene oxide–NaClO₃ composite have been prepared by solution casting technique with different weight percentages as a polymer electrolyte for battery application. The prepared composites were characterized by various tools like XRD, FTIR and SEM. The X-ray diffraction analysis shows the complexation of polymer with salt and existence of both crystalline and amorphous phases. From FTIR spectra confirms the formation of PEO–NaClO₃ composites. SEM images shows the grains are highly agglomerated and its average size increases with increase in salt ratio. Frequency dependence of dielectric property and ac electrical conductivity of polymer electrolytes were studied within the frequency range of 50 Hz to 5 MHz using complex impedance analysis technique. Ionic conductivity follows Arrhenius type behavior as a function of temperature. The fabricated cell of 25 wt.% of PEO–NaClO₃ composites generated high current of 1.79 A.     

SAXS/DSC/WAXD study of TiO2 nanoparticles and the effect of γ-radiation on nanopolymer electrolyte

Nanostructured polymer electrolytes are very attractive materials for components of batteries and opto-electronic devices. (PEO)₈ZnCl₂ polymer electrolytes and nanocomposites were prepared using Poly(ethylene oxide) (PEO) γ-irradiated with a selected dose of 529 kGy and with an addition of 10% of TiO₂ nanograins. The influence of the added nanosize TiO₂ grains on the polymer electrolytes and the effect of the γ-radiation from a Co-60 source were studied by small-angle X-ray scattering (SAXS) simultaneously recorded with differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) at the synchrotron ELETTRA. Infrared (IR) and impedance spectroscopy (IS) were also performed [1]. It was shown by previously performed IS that the room temperature conductivity of the nanocomposite polymer electrolyte increased more than two times above 65 °C, relative to pure composites of PEO and salts. We observed all changes between 20 °C and 100 °C for treated and as prepared polymer electrolyte in the SAXS, DSC and WAXD spectra and especially during the phase transition to the super-ionic phase at 65 °C [2] and [3]. The SAXS/DSC measurements yielded insight into the temperature-dependent changes of the grains of the electrolyte as well as into the differences due to different heating and cooling rates. The crystal structure and the melting and crystallization temperatures of the nanosize grains were revealed by the simultaneous WAXD measurements.     

Preparation and characterization of PEG–Mg(CH3COO)2–CeO2 composite polymer electrolytes for battery application

Composite polymer electrolytes based on poly(ethylene glycol) (PEG), magnesium acetate [Mg(CH₃COO)₂], and x wt% of cerium oxide (CeO₂) ceramic fillers (where x = 0, 5, 10, 15 and 20, respectively) have been prepared using solution casting technique. X-ray diffraction patterns of PEG–Mg(CH₃COO)₂ with CeO ₂ ceramic filler indicated the decrease in the degree of crystallinity with increasing concentration of the filler. DSC measurements of PEG–Mg(CH₃COO)₂–CeO₂ composite polymer electrolyte system showed that the melting temperature is shifted towards the lower temperature with increase of the filler concentration. The conductivity results indicate that the incorporation of ceramic filler up to a certain concentration (i.e. 15 wt%) increases the ionic conductivity and upon further addition the conductivity decreases. The transference number data indicated the dominance of ion-type charge transport in these specimens. Using this (PEG–Mg(CH₃COO)₂–CeO₂) (85-15-15) electrolyte, solid-state electrochemical cell was fabricated and their discharge profiles were studied under a constant load of 100 kΩ.     

Conductivity studies of plasticized PEO-Lithium chlorate–FIC filler composite polymer electrolytes

A new report of the synthesis of (PEO/plasticizer)LiClO₄–Li_1.3Al_0.3Ti_1.7(PO₄)₃ polymer electrolyte films prepared by the solution-cast technique is represented in this work. DSC trace revealed that T_g decreased with the increase of plasticizer content in the polymer electrolyte films. SEM morphology showed that the surface morphology of films was relatively smooth and homogeneous. Conductivity studies by EIS measurement indicated that the temperature dependence of ionic conductivity of films followed Vogel–Tamman–Fulcher (VTF) equation. The pre-exponential factor (A) and the pseudo activation energy (E_a) increased with the increase of plasticizer content in the polymer electrolyte films. At the 40 wt.% plasticizer content, A and E_a respectively had a maximum.     

Study of effect of composition, irradiation and quenching on ionic conductivity in (PEG) x : NH4NO3 solid polymer electrolyte

We have prepared, characterized and investigated a new PEG-2000 based solid polymer electrolyte (PEG) _x : NH₄NO₃. Ionic conductivity measurements have been made as a function of salt concentration as well as temperature in the range 265–330 K. Selected compositions of the electrolyte are exposed to a beam of 8 MeV electrons and ⁶⁰Co γ-rays to an accumulated dose of 10 kGy to study the effect on ionic conductivity. The electrolyte samples are also quenched at liquid nitrogen temperature and conductivity measurements are carried out. The ionic conductivity at room temperature exhibits a characteristic peak for the composition, x = 46. Electron beam irradiation results in an increase in conductivity for all compositions by a factor of 2–3. Exposure to γ-rays enhances the conductivity by one order of magnitude. Quenching at low temperature has resulted in an increase in conductivity by 1–2 orders of magnitude. The enhancement of conductivity upon irradiation and quenching is interpreted as due to an increase in amorphous region and decrease in crystallinity of the electrolyte. DSC and NMR measurements also support this conclusion.     

Enhancement of the ionic conductivity of poly(ethylene oxide) electrolyte film by polyaniline addition

To improve the electrical conductivity of LiClO₄–poly(ethylene oxide) (PEO) complex, nonconductive polyaniline (NPANI) was employed as an additive. The electrical conductivity of the PEO–LiClO₄–NPANI electrolyte was at least ten times that of the original PEO–LiClO₄ electrolyte. The amine and/or imine nitrogen atoms in the NPANI polymer chain as well as the oxygen atoms in the PEO poly-merchain attracted the Li⁺ ions, and ion-dipole interaction occurred. The interaction enhanced the mobility of the ClO₄ ^– ions. The positively charged nitrogens were electronically stabilized in the entire polymer chain because NPANI had conjugated electrons. The mechanism is unique and different from those of other polymer additives. It is the very first example in which NPANI was employed as the additive for the PEO solid electrolyte and in which NPANI was found to be an effective additive. In addition, the NPANI addition hardly affected the physical properties of the PEO matrix such as the glass transition temperature and the melting temperature.     

Morphology and conductivity studies of a new solid polymer electrolyte: (PEG)<Subscript>x</Subscript>LiClO<Subscript>4</Subscript>

A new solid polymer electrolyte, (PEG)_xLiClO₄, consisting of poly(ethylene)glycol of molecular weight 2000 and LiClO₄ was prepared and characterized using XRD, IR, SEM, DSC, NMR and impedance spectroscopy techniques. XRD and IR results show the formation of the polymer-salt complex. The samples with higher salt concentration are softer, less opaque and less smooth compared to the low salt concentration samples. DSC studies show an increase in the glass transition temperature and a decrease in the degree of crystallinity with increase in the salt concentration. Melting temperature of SPEs is lower than the pure PEG 2000. Room temperature¹H and⁷Li NMR studies were also carried out for the (PEG)_xLiClO₄ system. The¹H linewidth decreases as salt concentration increases in a similar way to the decrease in the crystalline fraction and reaches a minimum at aroundx = 46 and then increases.⁷Li linewidth was found to decrease first and then to slightly increase after reaching a minimum atx = 46 signifying the highest mobility of Li ions for this composition. Room temperature conductivity first increases with salt concentration and reaches a maximum value (σ = 7.3 × 10⁻⁷ S/cm) atx = 46 and subsequently decreases. The temperature dependence of the conductivity can be fitted to the Arrhenius and the VTF equations in different temperature ranges. The ionic conductivity reaches a high value of ∼10 ⁻⁴S/cm close to the melting temperature.     

Electrical and morphological analysis of chitosan:AgTf solid electrolyte

Solution cast technique is employed to prepare solid polymer electrolyte films based on chitosan (host polymer) and silver triflate (AgCF₃SO₃, doping salt) using (1%) acetic acid as a common solvent. The effect of salt concentration on both EP and bulk materials dielectric properties has been analyzed. Physically the original relationship between the bulk dielectric constant and DC conductivity has been interpreted. It is demonstrated that the dielectric constant and dielectric loss values decrease at higher temperatures due to the reduction of silver ions. Scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDAX) indicate the presence of metallic silver particles. The ac conductivity spectra shows three distinct regions and obeys the Jonscher's power law at high frequency regions. The temperature dependence of frequency exponent (s) shows the crossover from CBH model to SP model.     

Synthesis and characterization of polyethylene oxide based nano composite electrolyte

Polyethylene oxide (PEO) – montmorillonite (MMT) composite electrolytes were synthesised by solution casting technique. The salt used for the study is Lithium perchlorate (LiClO₄). The morphology and percentage of crystallinity data were obtained through X-ray Diffraction and Differential Scanning Caloriemetry. The ionic conductivity of the polymer electrolytes was studied by impedance spectroscopy. The addition of MMT resulted in an increase in conductivity over the temperature range of 25–60^°C. The ionic conductivity of a composite polymer electrolyte containing 1.2 wt% MMT was 1 × 10^?5 S cm^?1 at 25^°C, which is at least one order of magnitude higher than that of the polymer electrolyte (4 × 10^?7S cm^?1). The increase in ionic conductivity is explained on the basis of crystallinity of the polymer electrolyte.     

The influence of graphene oxide on the optical,thermal, electrical,and dielectric properties of PVA/PEO composite

The incorporation of nanoscale organic or inorganic components into polymer blend is a key strategy for optimizing the efficiency of material features such as structural, physical, chemical, optical, electrical, and thermal characteristics. Polymer nanocomposites are a new type of material created with nanostructure additives such as metals, metal oxides, and so on. Transition metal oxides such as graphene oxide have been extensively studied for applications including electrical, optical, and mechanical properties over the last several decades. Samples of polyvinyl alcohol and polyethylene oxide (PVA/PEO) loaded with different quantities of graphene oxide nanosheets (GO) were created using the casting technique. Various techniques were used to characterize the produced samples, including XRD, FTIR, SEM, UV/Vis, DSC, TGA, and dielectric characteristics. XRD verified the semicrystalline structure of the PVA/PEO blend, with crystallinity decreasing as the GO nanosheets percentage increased. With the decreasing frequency and varied concentrations of GO nanosheets, the FTIR absorption spectra demonstrate a shift in peak locations and intensity fluctuations. The crystalline regions have a roughly spherical shape, as shown in SEM pictures. The optical band gap (direct and indirect) is calculated using UV–Vis spectra, which decreases with increasing dopant concentration. The single glass transition temperature (T_g) is seen in the DSC analysis, indicating that PVA and PEO are miscible. The inclusion of filler changes the amorphous phase, resulting in a variation in melting temperature (T_m). The dynamic ion activity of the produced samples was determined using the frequency-dependent composite films (AC conductivity). At various concentrations and room temperatures (RT), the dielectric constant (ε′), dielectric loss (ε″), and tanδ versus frequency graphs were also obtained. The ionic conductivity of composite PVA/PEO/GO samples increased at room temperature with the addition of graphene oxide reaching a maximum of 10^–9 S/c. These results are projected to have an important effect on different applications, especially energy storage, polymer solar cells, and polymer organic semiconductor.

     

Studies on structural,electrical and dielectric properties of nickel ion conducting polyvinyl alcohol based polymer electrolyte films

Polyvinyl alcohol (PVA) complexed with different weight percent ratios of Nickel Bromide (NiBr₂) salt were prepared by using solution cast technique. X-ray diffraction analysis confirmed the complexation of the salt with the polymer. Differential scanning calorimetry was used to determine the glass transition and melting temperatures of pure PVA and PVA:NiBr₂ complexed films. Electrical conductivity was measured using ac impedance analyzer in the frequency and temperature range 1 Hz–1 MHz and 303–373 K respectively. It was observed that the magnitude of electrical conductivity increases with NiBr₂ salt concentration as well as temperature. Frequency dependence electrical conductivity of the complexed polymer electrolyte films follows the Jonscher’s equation. The dielectric behavior was analyzed using dielectric permittivity\(\left( {{\varepsilon ^\prime}} \right)\) and loss tangent \(\left( {\tan \delta } \right)\) of the samples. Relaxation time was determined from the variation of loss tangent with frequency at different temperatures. The modulus spectra indicated the non-Debye nature of the material.     

PEO基固态聚合物电解质膜的静电纺丝制备及性能EI北大核心CSCD

PEO基固态聚合物电解质被认为是目前固态锂电池领域极具产业化前景的固态电解质。为适应工业化生产,采用静电纺丝技术制备PEO/LiClO_(4)固态聚合物电解质(SPE),研究纺丝电压、纺丝液质量浓度和锂盐含量对SPE纤维膜形貌和直径的影响。通过扫描电子显微镜观察SPE中纤维的形貌,利用Image J软件分析SPE纤维的直径。通过DSC,XRD,FTIR-ATR和拉伸测试等手段对静电纺丝制备的SPE纤维膜的组成、结构、性能等进行研究。结果表明:当纺丝电压为15 kV、PEO/LiClO_(4)纺丝液质量浓度为6%、[EO]∶[Li^(+)]=10∶1(摩尔比)时,静电纺丝方法制备的PEO/LiClO_(4) SPE纤维膜具有较好的纤维形貌,平均直径为557 nm,分布均一;当[EO]∶[Li^(+)]=10∶1时,SPE纤维膜中PEO的熔点仅为53.8℃,结晶度低至18.9%;电解质在30℃时的离子电导率达到5.16×10^(-5)S·cm^(-1),同时具备良好的电化学稳定性和界面稳定性。     

Novel PEO-based composite solid polymer electrolytes incorporated with active inorganic–organic hybrid polyphosphazene microspheres

Inorganic–organic hybrid poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol) (PZS) microspheres with active hydroxyl groups were incorporated in poly(ethylene oxide) (PEO), using LiClO₄ as a dopant salt, to form a novel composite polymer electrolyte (CPE). The polymer chain flexibility and crystallinity properties are studied by DSC. The effects of active PZS microspheres on the electrochemical properties of the PEO-based electrolytes, such as ionic conductivity, lithium ion transference number, and electrochemical stability window are studied by electrochemical impedance spectroscopy and steady-state current method. Maximum ionic conductivity values of 3.36 × 10⁻⁵ S cm⁻¹ at ambient temperature and 1.35 × 10⁻³ S cm⁻¹ at 80 °C with 10 wt.% content of active PZS microspheres were obtained and the lithium ion transference number was 0.34. The experiment results showed that the inorganic–organic hybrid polyphosphazene microspheres with active hydroxyl groups can enhance the ionic conductivity and increase the lithium ion transference number of PEO-based electrolytes more effectively comparing with traditional ceramic fillers such as SiO₂.