Preparation Of Solid Polymer Electrolyte Research Articles

Hybrid Electrolyte Based on PEO and Ionic Liquid with In Situ Produced and Dispersed Silica for Sustainable Solid-State Battery

This work introduces the synthesis of hybrid polymer electrolytes based on polyethylene oxide (PEO) and electrolyte solution bis(trifluoromethane)sulfonimide lithium salt/ionic liquid 1-ethyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide (LiTFSI/EMIMTFSI) with in situ produced and dispersed silica particles by the sol–gel method. Conventional preparation of solid polymer electrolytes was followed by desolvation of lithium salt in a polymer matrix of PEO, which, in some cases, additionally contains plasticizers. This one-pot synthesis is an alternative route for fabricating a solid polymer electrolyte for solid-state batteries. The presence of TFSI- reduces the crystallinity of the PEO matrix (plasticizing effect), increases the dissociation and solubility of LiTFSI in the PEO matrix because of a highly delocalized charge distribution, and reveals excellent thermal, chemical, and electrochemical stability. Tetraethylorthosilicate (TEOS) was chosen due to the slow reaction rate, with the addition of (3-glycidyoxypropyl)trimethoxysilane (GLYMO), which contributes to the formation of a silica network. FTIR studies confirmed the interactions between the silica, the polymer salt, and EMIMTFSI. Impedance spectroscopy measurements were performed in a wide range of temperatures from 25 to 70 °C. The electrochemical performance was explored by assembling electrolytes in LiCoO2 (LCO), NMC(811), and LiFePO4 (LFP) coin half-cells. The HPEf15 shows a discharge capacity of 143 mA/g for NMC(811) at 0.1 C, 134 mA/g for LCO, and 139 mA/g for LFP half-cells at 0.1 C and 55 °C. The LFP half-cell with a discharge capacity of 135 mA/g at 0.1 C (safety potential range of 2.8 to 3.8) obtained a cyclability of 97.5% at 55 °C after 100 cycles. Such a type of electrolyte with high safety and good electrochemical performance provides a potential approach for developing a safer lithium-ion battery.

Effect of Sodium Iodide on Structural, Electrical and Optical Properties of Polyethylene Oxide/ Carboxymethyl Cellulose Blends

The production of highly potential Solid Polymer Electrolyte (SPE) materials has been the subject of extensive research. Due to their high flexibility, superior processability and enhanced resistance to electrodes during the charging/discharging process, they found to exhibit wide applications when compared to liquid or gel. In the present study, SPE films with 30/70 composition of Polyethylene oxide/Carboxymethyl cellulose blend, doped with Sodium Iodide (NaI) were prepared using a simple solution cast technique. The optical properties of the prepared samples were studied by UV–Vis spectroscopy technique and the results show that, the energy band gap decreases with the increase of salt concentration which is due to the enhancement of amorphous nature with the concentration of salt and is as evidenced from X-Ray diffraction studies. The electrical properties of the samples were studied using impedance analyser. The dielectric constant of the prepared samples decreases exponentially with frequency of applied electric field. In addition, the AC conductivity of the blend was found to increase with increase in salt concentration and the maximum conductivity was observed for 0.03% NaI salt doped Polyethylene oxide/Carboxymethyl cellulose blend. Thus, the said samples can be used in the preparation of SPE’s

Poly(lactic acid) block improves ambient-temperature ionic conductivity of pentablock copolymer electrolyte

A polystyrene-b-poly(lactic acid)-b-poly(ethylene oxide)-b-poly(lactic acid)-b-polystyrene pentablock copolymer electrolyte (PSLE) is successfully prepared by ring-opening polymerization (ROP) of DL-lactide (DL-LA) with poly(ethylene oxide) (PEO) followed by atom transfer radical polymerization (ATRP) with styrene. Poly(lactic acid) (PLA) block made by the polymerization of DL-LA can not only reduce the crystallinity of PEO, but also balance the coordination properties of Li+, while polystyrene (PS) block acts as a hard block to improve the mechanical properties of PSLE. Here, the obtained PSLE achieves high ionic conductivity (1.3 × 10−4 S cm−1) under ambient temperature and wide electrochemical stable window (4.2 V). In addition, the PSLE shows outstanding stability, allowing the Li/PSLE/Li cell to cycle stably for more than 600 h at 0.1 mA cm−2 without an increase in polarization voltage. And LiFePO4/PSLE/Li cell shows an initial discharge capacity of 159 mA h g−1 and keeps a capacity retention of 94.6 % after 200 cycles at 0.1C under ambient temperature. The LiNi0.6Co0.2Mn0.2O2/PSLE/Li cell also delivers good cycling performance. These results suggest that multiblock copolymer electrolyte is very promising material for the preparation of solid polymer electrolytes (SPEs) suitable for lithium metal batteries.

ИССЛЕДОВАНИЕ ТВЕРДЫХ ЭЛЕКТРОЛИТОВ НА ОСНОВЕ СМЕСИ ПОЛИМЕРОВ ПОЛИВИНИЛИДЕНФТОРИДА И ГИДРИРОВАННОГО БУТАДИЕН-НИТРИЛЬНОГО КАУЧУКА

The paper discusses the preparation of solid polymer electrolytes based on a blend of polyvinylidene fluoride and hydrogenated butadiene nitrile rubber with lithium bis(trifluorosulfonyl)imide prepared by solution casting technique. The films were characterized by X-ray diffraction analysis, FTIR spectroscopy, scanning electron microscopy, and differential scanning calorimetry. The influence of the polymer blend composition on the ionic conductivity of electrolytes was studied. According to the impedance spectroscopy data, it was found that the ionic conductivity of solid polymer electrolytes increases from 10-5 to 10-4 S/cm at room temperature with increasing the content of hydrogenated butadiene nitrile rubber up to 50 wt. % in the polymer blend matrix.

Solvent Evaporation Rate as a Tool for Tuning the Performance of a Solid Polymer Electrolyte Gas Sensor.

Solid polymer electrolytes show their potential to partially replace conventional electrolytes in electrochemical devices. The solvent evaporation rate represents one of many options for modifying the electrode-electrolyte interface by affecting the structural and electrical properties of polymer electrolytes used in batteries. This paper evaluates the effect of solvent evaporation during the preparation of solid polymer electrolytes on the overall performance of an amperometric gas sensor. A mixture of the polymer host, solvent and an ionic liquid was thermally treated under different evaporation rates to prepare four polymer electrolytes. A carbon nanotube-based working electrode deposited by spray-coating the polymer electrolyte layer allowed the preparation of the electrode-electrolyte interface with different morphologies, which were then investigated using scanning electron microscopy and Raman spectroscopy. All prepared sensors were exposed to nitrogen dioxide concentration of 0-10 ppm, and the current responses and their fluctuations were analyzed. Electrochemical impedance spectroscopy was used to describe the sensor with an equivalent electric circuit. Experimental results showed that a higher solvent evaporation rate leads to lower sensor sensitivity, affects associated parameters (such as the detection/quantification limit) and increases the limit of the maximum current flowing through the sensor, while the other properties (hysteresis, repeatability, response time, recovery time) change insignificantly.

An Investigation into the PVA:MC:NH4Cl-Based Proton-Conducting Polymer-Blend Electrolytes for Electrochemical Double Layer Capacitor (EDLC) Device Application: The FTIR, Circuit Design and Electrochemical Studies.

In this report, the preparation of solid polymer electrolytes (SPEs) is performed from polyvinyl alcohol, methyl cellulose (PVA-MC), and ammonium chloride (NH4Cl) using solution casting methodology for its use in electrical double layer capacitors (EDLCs). The characterizations of the prepared electrolyte are conducted using a variety of techniques, including Fourier transform infrared spectroscopy (FTIR), electrical impedance spectroscopy (EIS), cyclic voltammetry (CV), and linear sweep voltammetry (LSV). The interaction between the polymers and NH4Cl salt are assured via FTIR. EIS confirms the possibility of obtaining a reasonably high conductance of the electrolyte of 1.99 × 10−3 S/cm at room temperature. The dielectric response technique is applied to determine the extent of the ion dissociation of the NH4Cl in the PVA-MC-NH4Cl systems. The appearance of a peak in the imaginary part of the modulus study recognizes the contribution of chain dynamics and ion mobility. Transference number measurement (TNM) is specified and is found to be (tion) = 0.933 for the uppermost conducting sample. This verifies that ions are the predominant charge carriers. From the LSV study, 1.4 V are recorded for the relatively high-conducting sample. The CV curve response is far from the rectangular shape. The maximum specific capacitance of 20.6 F/g is recorded at 10 mV/s.

Solid Polymer Electrolytes Based on Cross-Linked Polybenzoxazine Possessing Poly(ethylene oxide) Segments Enhancing Cycling Performance of Lithium Metal Batteries

Solid polymer electrolytes (SPEs) are suitable materials for safety enhancements of high-energy-density lithium metal batteries. Low ionic conductivity and poor interfacial compatibility could be the major issues to be addressed for SPEs. In this work, a cross-linked polybenzoxazine polymer with poly(ethylene oxide) (PEO) segments (CR-PEO-PBz) has been synthesized and used as a polymeric matrix for preparation of SPEs. The cross-linked structure contributes to suppression of PEO crystallization. PEO-PBz is also used as a binder to reduce the interfacial resistance between the electrode and the electrolyte. The features enhance the lithium ion transportation and increase the ionic conductivity of the corresponding SPE (5.32 × 10–¹ mS cm–¹ at 60 °C). CR-PEG-PBz also exhibits the ability to prevent lithium dendrite growth with promotion of uniform lithium deposition. The LiFePO₄/Li coin cells made with the SPEs demonstrate a high initial capacity of 142 mAh g–¹ at 0.2C and 60 °C and a 93% initial capacity after a 100-cycle test. The cells could be operated at 30, 40, and 50 °C, thus proving the capability of the SPE at various temperatures.

The compatibility of chitosan with divalent salts over monovalent salts for the preparation of solid polymer electrolytes

Abstract In this study the compatibility of chitosan (CS) with divalent inorganic salt is discussed. Solid polymer electrolytes (SPEs) consist of CS as a host polymer and magnesium triflate (MgTf) as a dopant divalent salt have been prepared by solution cast technique. The room temperature DC ionic conductivity of CS-based SPE containing 50 wt% of MgTf is determined to be around ≈10−4 S/cm. The surface morphology of the films are then examined using a field emission scanning electron microscopy (FE-SEM). The crystalline phase of pure CS is found to reduce upon the addition of MgTf salt. The compatibility of CS with divalent salts are discussed at high salt concentration on the bases of the surface morphology and X-ray diffraction (XRD) results. The smooth surface micrographs and broad peaks of XRD spectra are interpreted in reference to lattice energy and cationic size of salt. The smooth surface and low resistance (Rb = 47.8 Ohm) at high salt content (50 wt%) are clear signs that CS is more compatible with divalent salts than with other monovalent salts. At low temperature range, the DC conductivity versus 1000/T is shown to follow the Arrhenius equation. The dispersion region of AC conductivity spectra has been used to calculate the frequency exponent, s. Based on the value of s as a function of temperature, different ion transport models have been discussed to interpret the pattern of DC ionic conductivity versus 1000/T. The appearance of peaks in M″ spectra and their absence in ɛ″ spectra reveals that the relaxation process is a non-Debye type.

Influence of solid polymer electrolyte preparation methods on the performance of (PEO–PMMA)–LiBF4 films for lithium-ion battery applications

Classical solution-cast and ultrasonic–microwave-irradiated solution-cast methods have been used for the preparation of solid polymer electrolyte (SPE) films comprising polymer matrix of poly(ethylene oxide) and poly(methyl methacrylate) blend and lithium tetrafluoroborate (LiBF4) ionic salt. These films have been characterized by employing the X-ray diffraction, Fourier transform infrared spectroscopy, dielectric relaxation spectroscopy, and electrochemical analyser. It is observed that the temperature-dependent ionic conductivity of these predominantly amorphous solid ion–dipolar complexes is governed by their dielectric permittivity and the relaxation times of various dynamical processes. The relaxation times and the dc ionic conductivity of these electrolyte materials obey the Arrhenius behaviour, whereas the normalized ac conductivity exhibits the time–temperature superposition scaling. The influence of sample preparation methods on the performance of SPE films and the suitability of these materials for the lithium-ion batteries has been explored by noting the relative changes in their structural, dielectric, electrical, ionic conductivity, and the electrochemical parameters.

Morphological, structural, dielectric and electrical properties of PEO–ZnO nanodielectric films

The morphological, structural, dielectric and electrical properties of aqueous solution-cast prepared poly(ethylene oxide)–zinc oxide (PEO–ZnO) nanocomposite films have been investigated as a function of ZnO nanoparticle concentrations up to 5 wt%. Scanning electron microscopy (SEM) images of these films show that the morphology of pristine PEO aggregated spherulites changes into fluffy, voluminous and highly porous with dispersion of ZnO nanoparticles into the PEO matrix. X-ray diffraction (XRD) study confirms that the crystalline phase of PEO greatly reduces at 1 wt% ZnO, and it again increases gradually with further increase of ZnO concentration. The dielectric relaxation spectroscopy (DRS) over the frequency range 20 Hz–1 MHz reveals that the real part of complex dielectric permittivity at audio frequencies decreases non-linearly whereas it remains almost constant at radio frequencies for these polymeric nanocomposites. Dispersion of nanosize ZnO particles into the PEO matrix reduces the values of dielectric permittivity which also exhibits a correlation with the dispersivity of ZnO nanoparticles. The relaxation peaks observed in the dielectric loss tangent and electric modulus spectra reveal that the electrostatic interactions of nanoscale ZnO particles with the ethylene oxide functional dipolar group of PEO monomer units decrease the local chain segmental dynamics of the polymer. Real part of ac conductivity spectra of these films have been analyzed by power law fit over the audio and radio frequency regions, respectively, and the obtained dc conductivity values for these regions differ by more than two orders of magnitude. The temperature dependent relaxation time and dc conductivity values of the nanodielectric material obey the Arrhenius relation of activation energies and confirm a correlation between dc conductivity and PEO chain segmental motion which is exactly identical to the characteristics of solid polymer electrolytes. Results imply that these nanocomposite materials can serve as low permittivity flexible nanodielectric for radio frequency microelectronic devices and also as electrical insulator for audio frequency operating conventional devices in addition to their suitability in preparation of solid polymer electrolytes.

Study of Solid Polymer Electrolytes for Room Temperature All-Solid-State Lithium Ion Batteries

All-solid-state lithium ion batteries based on solid polymer electrolytes (SPEs) have shown high commercialization and technical values. However, severe capacity decay of the batteries occurs as a decrease of working temperature. This is mainly due to low lithium ionic conductivity of SPEs at room temperature. Hence, preparation of SPEs with high ionic conductivities for wide temperature applications of all-solid-state lithium ion batteries remains a challenge. In this study, preparation, structure and electrochemical properties of SPEs as well as fabrication of all-solid-state lithium ion batteries using the SPEs are investigated. Results show that lithium ionic conductivity and electrochemical stability of the SPEs can be adjusted by simultaneously grafting cyclic carbonate and combed poly(ethyleneoxide) on polysiloxane. The LiFePO4/Li batteries with the SPEs present excellent cycling performance in the temperature range from 25 to 100 oC.

Proton conducting solid polymer electrolytes based carboxymethyl cellulose doped ammonium chloride: ionic conductivity and transport studies

The present work focuses on the preparation of solid polymer electrolytes (SPEs) based carboxymethyl cellulose, CMC as host polymer doped with ammonium chloride, AC (0–20 wt.%) as ionic dopant via solution casting technique. The ionic conductivity and transport parameter of SPEs films were analyzed using electrical impedance spectroscopy in the frequency range of 1 Hz–50 MHz at selected temperature of 303–383 K. The highest ionic conductivity of 1.43 × 10−3 S/cm was obtained at 16 wt.% AC. Temperature-dependent ionic conductivity showed that the ionic conductivity obeys Arrhenius rule where R2~1 and thermally assisted. Transport studies showed that the ionic conductivity was influenced by the ionic mobility and diffusion coefficient.

Influence of Cobalt (II) Chloride Catalysed on the Thermal and Optical Characterization of PEO Based Solid Polymer Electrolytes

Solution-casting technique was employed for the preparation of solid polymer electrolyte based polyethylene oxide (PEO) with 0, 1, 3 and 5 weight percentage cobalt chloride (CoCl2) films were characterized by X-ray Diffractometry (XRD), Differrential Scanning Calorimetry (DSC), Scanning Electron Microscope (SEM) and Ultra Violet-Visible (UV-Vis.) Spectroscopy methods. The optical band gaps, absorption band edges and Urbach energy shows decrease with increasing of Co+2 ion concentration in the polymer matrix because of the formation of free radicals or cluster. The Thermogravimetry (TG) and Derivative Thermogravimetry (DTG) were used to examine the thermal stability of the film and it was found that the stability of the complexes is higher than that of the pure PEO due to the addition of CoCl2. The wavelength position of a fluorescence emission band varied by increasing of a dopant wt % of salt.

Stale elektrolity typu polimer-ciecz jonowa o duzym przewodnictwie jonowym otrzymywane metoda polimeryzacji in situ

Solid polymer electrolytes containing ionic liquids (ILs) were prepared by the photopolymerization of monomer-IL homogenous mixtures. This methods enables the preparation of solid polymer electrolytes in reaction carried out at room temperature in the time of about 10 min. The appropriate selection of the substrate allowed to obtain the high ionic conductivity of the solid polymer electrolytes (of the order of 10 -3 - 2. 10 -2 S/cm), in some cases exceeding the conductivity of the ionic liquid used.

New method for the preparation of solid polymer electrolyte based on poly(vinylidene fluoride-co-hexafluoropropylene)

A novel solid polymer electrolyte (pore-gel SPE) has been found to provide superior SPE having a high conductivity, good mechanical strength and low solution leakage. This pore-gel SPE was prepared from gelation in pores of polymer membrane with electrolyte solution incl uding solvent. The conductivity of pore-gel type PVDF-HFP/ TEABF4 (Tetraethylammomium tetrafluoroborate) membrane can reach 1.6×10 −1 Scm −1 . The tensile strength of this membrane was 4,000 kPa, which is about 23 times larger than that of gel-type SPE with the same composition. Pore- gel SPE reduced solution leakage to 0%, compared with 2% of hybrid-type SPE after 2.0 hr leakage test in PVDF- HFP/TEABF4 membrane.

Sol-Gel Preparation of Organic-Inorganic Hybrid Polymer Electrolytes and Their Electrochemical Characterizations

For the preparation of solid polymer electrolytes with high conductivity and good mechanical properties, organically modified ceramic electrolytes were prepared based on low molecular weight poly(ethylene glycol), lithium salt and an inorganic matrix produced by sol-gel process of tetraethoxysilane and a new poly(ethylene glycol)-modified sol-gel precursor which was synthesized by the reaction of mono-methoxy terminated poly(ethylene glycol) and 3-isocyanatopropyl triethoxysilane. Transparent and self-supporting films were obtained showing high ionic conductivities (3.2 × 10−6 ∼ 1.4 × 10−4 S/cm) at room temperature.

Study of radiation-grafted FEP-G-polystyrene membranes as polymer electrolytes in fuel cells

Proton exchange membranes for fuel cell applications were synthesized by pre-irradiation grafting of styrene/divinylbenzene mixtures into poly(fluoroethylene- co-hexafluoropropylene) films and subsequent sulfonation. Grafting of pre-existing films overcomes the problem of shaping the grafted polymer into thin membranes and makes this process a potentially cheap and easy technique for the preparation of solid polymer electrolytes. The grafted membranes were characterized by measuring their ion exchange capacity, swelling, specific resistivity and area resistance. Due to their thickness in the range 67–211 μm, some of the membranes have a considerably lower resistance than the most widely used membrane Nafion ® 117 (DuPont). The short-term and long-term performance of these membranes was investigated in H 2 O 2 fuel cells. Thin (< 100 μm), highly crosslinked (12% divinylbenzene) membranes show the best performance in the fuel cells. Tests for periods of up to 1400 h were performed to examine membrane stability and the degradation of grafted membranes.

Ionically conductive thin polymer films prepared by plasma polymerization, part 9: Vapor‐phase preparation of solid polymer electrolytes composed of plasma polymer and lithium trifluoromethanesulfonate

AbstractSolid polymer electrolytes composed of plasma‐polymerized dimethyl‐2‐[(2‐ethoxy‐ethoxy)ethoxy]vinylsilane and thermal vapor‐deposited lithium trifluoromethanesulfonate have been prepared, and characterized using electron spectroscopy for chemical analysis (ESCA), Fourier transform/infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and electrochemical techniques. The obtained solid polymer electrolyte films of about 1 μm thickness were uniform and pinhole‐free. Room temperature conductivity of 8 × 10−6S/cm has been observed. This value depends on the substrate temperature during the plasma polymerization, and the variation of the ionic conductivity with temperature can be described by using a Williams–Landel–Ferry equation.

Ionically conductive thin polymer films prepared by plasma polymerization—Part 8. Vapor-phase preparation of solid polymer electrolytes composed of plasma polymer and vapor-deposited lithium iodide complex

Ultra-thin, uniform, pinhole-free solid polymer electrolyte films of approximately 1 μm thickness were prepared by the complexation of plasma polymerized dimethyl-2-[(2-ethoxyethoxy)ethoxy]-vinylsilane (DEVS) and thermally vapor-deposited lithium iodide. The results of FT- ir and EPMA measurements indicate that the structure of the plasma polymerized DEVS is very similar to poly(DEVS). Room temperature conductivities were as high as the order of 10 −6 S cm −1(10 2 ohm cm 2 resistance per unit area of as prepared solid polymer electrolyte).

Preparation of new solid polymer electrolyte composites for water electrolysis

A new simple procedure for the preparation of Solid Polymer Electrolytes (SPE)—electrocatalyst composites for water electrolysis-has been developed. In this new procedure (French patent, 1987), microparticles of noble metal electrocatalyst are precipitated simultaneously inside and outside near both surfaces of a perfluorinated ion-exchange membrane by chemical reduction of cationic precursor salts. The structure of the electrodes bonded onto the SPE has been investigated by scanning electron microprobe analysis and transmission electron microscopy. The effects of temperature and nature of anodic electrocatalyst on the cell voltage-current density relation are reported. Anodic overvoltage, cathodic overvoltage, ohmic drop within the SPE and roughness factor of the electrodes have been measured using an internal RHE reference electrode. The composites prepared according to this new procedure present low noble metal loadings (< 1 mg cm −2), low cell voltage (1.75 V at 1 A cm −2 and 80°C) and long time stability (over 15,000 h of continuous electrolysis). Partial results concerning the use of such composites for H 2/O 2 SPE fuel cell applications are also reported.