Enhanced ionic conductivity in novel nanocomposite gel polymer electrolyte based on intercalation of PMMA into layered LiV3O8

In the present work, a novel polymer electrolyte based on poly(methyl methacrylate) (PMMA)/layered lithium trivanadate (LiV₃O₈) nanocomposite has been investigated. X-ray diffraction (XRD) study shows that d-spacing is increased from 6.3?±?0.1 Å to 12.8?±?0.1 Å upon intercalation of the polymer into the layered LiV₃O₈. Room temperature ionic conductivity of the obtained nanocomposite gel polymer electrolyte is found to be superior to that of conventional PMMA-based gel polymer electrolyte. Enhancement in ionic conductivity of the nanocomposite gel electrolyte is attributed to the formation of a two-dimensional channel as a result of decreased interaction between Li⁺ and V₃O ₈ ^? layers as confirmed by FTIR. SEM results show aggregation of nanocomposite particles resulting from extension of some of the polymer chains from interlayer to the edge providing paths for Li⁺ ion transport. Interfacial stability of nanocomposite gel electrolyte is also found to be better than that of the conventional PMMA-based gel polymer electrolyte.     

Effect of Al2O3 nanoparticles on ionic conductivity of PVdF-HFP/PMMA blend-based Na+-ion conducting nanocomposite gel polymer electrolyte

Journal of Solid State Electrochemistry - In the present work, the effect of dispersion of Al2O3 nanoparticles on ionic conductivity of non-aqueous PVdF-HFP/PMMA blend-based nanocomposite gel...     

Effect of IL incorporation on ionic transport in PVdF-HFP-based polymer electrolyte nanocomposite doped with NiBTC-metal-organic framework

Journal of Solid State Electrochemistry - Ni-based metal-organic framework (MOF), nickel 1,3,5-benzene tricarboxylate (NiBTC) has been synthesized by solvothermal method and incorporated with ionic...     

Protic ionic liquid-based gel polymer electrolyte: structural and ion transport studies and its application in proton battery

Proton-conducting free standing gel polymer electrolyte (GPE) films containing protic ionic liquid, 1-butyl-3-methylimidazolium hydrogen sulphate, immobilized in blend of poly(vinylidenefluoride-co-hexafluoropropylene) and poly(vinylpyrrolidone) have been prepared by solution-cast technique. Films have been characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), differential scanning calorimetry (DSC), complex impedance spectroscopy, and cyclic voltammetry. Ionic conductivity of the semicrystalline and porous GPE films has been obtained as ~3.9?×?10^?3 S cm^?1 at room temperature. Protonic nature of conduction in the films has been established by performing cyclic voltammetry and complex impedance spectroscopy on the cells having both blocking (stainless steel) and both reversible electrodes (Zn + ZnSO₄.7H₂O). The electrochemical stability window of the films has been found as ~3.8 V. The highest conducting film has been used as a separator and proton conductor to fabricate a proton battery of configuration Zn + ZnSO₄.7H₂O |GPE film| PbO₂ + V₂O₅. The battery shows an open circuit voltage of ~1.62 V. Energy density of the cell has been obtained as 35.2 W h kg^?1 for low current drain. Rechargeability of the cell has been tested for ten cycles. The maximum discharge capacity of the cell has been obtained as ~2.50 mA h g^?1 during the first discharge cycle.     

Effect of MgO nanoparticles on ionic conductivity and electrochemical properties of nanocomposite polymer electrolyte

This paper analyzes the comparison between the performances and morphologies of the PMMA gel and composite electrolyte membrane with nanosized MgO particles. These polymer electrolytes were studied in detailed using XRD, DSC, SEM and AC impedance analysis. The conductivity enhancement has been attributed to the addition of ceramic filler that yields a significant increase of surface to volume ratio related to the decrease in glass transition temperature values in the composite polymer electrolyte. Good interfacial stability at the electrode/electrolyte interface resulted on account of the improved ion dissociation by ceramic filler and a rise in the room temperature conductivity (8.14 × 10⁻³ S cm⁻¹) due to the iono-covalent or Lewis acid–base bonds to the ions and ether oxygen base groups was also observed. Further enhancement of conductivity has been observed on MgO surface, as Lewis-acidic sites interact with both PMMA and ClO₄⁻ ions. The percentage of swelling was found to increase with increasing soaking periods upto 12 h. Beyond that soaking period, it was found that there was a negligible increase in the % of swelling.     

Structure and ion transport in an ethylene carbonate-modified biodegradable gel polymer electrolyte

The influence of ethylene carbonate (EC) addition on 85poly(ε-caprolactone):15Lithium thiocyanate (85PCL:15LiSCN) polymer electrolyte is investigated using X-ray diffraction, impedance spectroscopy, Wagner's polarization and electrochemical measurements. The results reveal that the amorphicity of the 85PCL:15LiSCN system increases with increase of EC content up to an optimal level of 40 wt.%. This is reflected in the electrical properties of the gel polymer electrolytes, i.e., the 40 wt.% EC-incorporated gel polymer electrolyte exhibits both high amorphicity and high electrical conductivity as compared to the other samples. The EC concentration dependences of dielectric constant and electrical conductivity show a similar trend, indicating that these properties are closely related to each other. The total ionic transference numbers of EC-incorporated gel polymer electrolytes are in the range 0.989–0.993, demonstrating that they are almost completely ionic conductors. The electrochemical stability window of the 40 wt.% EC-incorporated gel polymer electrolyte is ∼4.1 V along with the electrical conductivity of 2.2 × 10⁻⁴ S cm⁻¹, which is significantly improved as compared to the 85PCL:15LiSCN system (3.0 V and 1.04 × 10⁻⁶ S cm⁻¹). Consequently, the addition of EC in the 85PCL:15LiSCN polymer electrolyte leads to a promising improvement in its various properties.     

Enhanced electrochemical properties of a novel polyvinyl formal membrane supporting gel polymer electrolyte by Al2O3 modification

Polyvinyl formal (PVFM)‐based dense polymer membranes with nano‐Al₂O₃ doping are prepared via phase inversion method. The membranes and also their performances as gel polymer electrolytes (GPEs) for lithium ion battery are studied by field emission scanning electron microscope, X‐ray diffraction, differential scanning calorimetry, mechanical strength test, electrolyte uptake test, electrochemical impedance spectroscopy, cyclic voltammetry, and charge–discharge test. The polymer membrane with 3 wt % nano‐Al₂O₃ doping shows the improved mechanical strength of 12.16 MPa and electrolyte uptake of 431.25% compared with 10.47 MPa and 310.59% of the undoped sample, respectively. The membrane absorbs and swells liquid electrolyte to form stable GPE with ionic conductivity of 4.92 × 10^?4 S cm^?1 at room temperature, which is higher than 1.77 × 10^?4 S cm^?1 of GPE from the undoped membrane. Moreover, the Al₂O₃‐modified membrane supporting GPE exhibits wide electrochemical stability window of 1.2–4.8 V (vs. Li/Li⁺) and good compatibility with LiFePO₄ electrode, which implies Al₂O₃‐modified PVFM‐based GPE to be a promising candidate for lithium ion batteries. © 2014 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2014 , 52, 572–577     

A novel gel polymer electrolyte based on poly ionic liquid 1-ethyl 3-(2-methacryloyloxy ethyl) imidazolium iodide

Poly ionic liquid 1-ethyl 3-(2-methacryloyloxy ethyl) imidazolium iodide (PEMEImI) as a single-ion conductor was designed and synthesized. When appropriate amount of suitable plasticizers, I₂ and polyacrylonitrile (PAN) were incorporated into it, the complex formed gel polymer electrolyte. Chemical structure, thermal behavior and ionic conductive properties of the gel polymer electrolyte were investigated by Raman spectra, UV-Vis spectra, differential scanning calorimetry (DSC), and complex impedance analysis, respectively. For the new gel polymer electrolyte, the ionic conductivity of about 1 × 10⁻³ S cm⁻¹ at room temperature was achieved.     

Structural,thermal, and impedance properties of a gel polymer electrolyte containing ionic liquid

The gel polymer electrolytes composed of ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BMImBF₄) and the copolymer of acrylonitrile (AN), methyl methacrylate (MMA), poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) are synthesized and characterized by FT‐IR spectra, TGA, DSC, and AC impedance measurements. IR spectra show that there is an interaction between PEO side chains of the copolymer and imidazolium cations. TGA measurements indicate that the gel polymer electrolytes are stable until 120°C. By using the equivalent circuit proposed, the experimental data and the simulated data fit very well. The bulk resistance R_b is found to decrease with the increase in BMImBF₄ content. Copyright © 2009 John Wiley & Sons, Ltd.     

Sensing H2O2 with layer-by-layer assembled Fe3O4–PDDA nanocomposite film

It was found that Fe₃O₄ nanoparticles (Fe₃O₄ NPs) possess intrinsic enzyme mimetic activity similar to that found in natural peroxidase. Here, we applied Fe₃O₄ NPs to the construction of efficient electrochemical sensor to detect the concentration of hydrogen peroxide. The sensor was fabricated with layer-by-layer assembly of Fe₃O₄ NPs and poly(diallyldimethylammonium chloride) (PDDA) through the electrostatic interaction, and the multilayer film was characterized with UV–vis absorption spectra, atomic force microscopy, and cyclic voltammetry. Moreover, the sensor showed prominent electrocatalytic activity toward the reduction of H₂O₂, and the interferences of ascorbic acid (AA) and uric acid (UA) were completely avoided. Unlike the inherent instability of enzyme, Fe₃O₄ NPs-based sensor demonstrated outstanding stability.     

Effect of plasticizers (EC or PC) on the ionic conductivity and thermal properties of the (PEO)9LiTf: Al2O3 nanocomposite polymer electrolyte system

A new plasticized nanocomposite polymer electrolyte based on poly (ethylene oxide) (PEO)-LiTf dispersed with ceramic filler (Al₂O₃) and plasticized with propylene carbonate (PC), ethylene carbonate (EC), and a mixture of EC and PC (EC+PC) have been studied for their ionic conductivity and thermal properties. The incorporation of plasticizers alone will yield polymer electrolytes with enhanced conductivity but with poor mechanical properties. However, mechanical properties can be improved by incorporating ceramic fillers to the plasticized system. Nanocomposite solid polymer electrolyte films (200–600 μm) were prepared by common solvent-casting method. In present work, we have shown the ionic conductivity can be substantially enhanced by using the combined effect of the plasticizers as well as the inert filler. It was revealed that the incorporating 15 wt.% Al₂O₃ filler in to PEO: LiTf polymer electrolyte significantly enhanced the ionic conductivity [σ _RT (max)?=?7.8?×?10^?6 S cm^?1]. It was interesting to observe that the addition of PC, EC, and mixture of EC and PC to the PEO: LiTf: 15 wt.% Al₂O₃ CPE showed further conductivity enhancement. The conductivity enhancement with EC is higher than PC. However, mixture of plasticizer (EC+PC) showed maximum conductivity enhancement in the temperature range interest, giving the value [σ _RT (max)?=?1.2?×?10^?4 S cm^?1]. It is suggested that the addition of PC, EC, or a mixture of EC and PC leads to a lowering of glass transition temperature and increasing the amorphous phase of PEO and the fraction of PEO-Li⁺ complex, corresponding to conductivity enhancement. Al₂O₃ filler would contribute to conductivity enhancement by transient hydrogen bonding of migrating ionic species with O–OH groups at the filler grain surface. The differential scanning calorimetry thermograms points towards the decrease of T _g , crystallite melting temperature, and melting enthalpy of PEO: LiTf: Al₂O₃ CPE after introducing plasticizers. The reduction of crystallinity and the increase in the amorphous phase content of the electrolyte, caused by the filler, also contributes to the observed conductivity enhancement.     

Electrodeposition and stripping of zinc from an ionic liquid polymer gel electrolyte for rechargeable zinc-based batteries

In this paper, we report on zinc deposition and stripping in an ionic liquid polymer gel electrolyte on gold and copper substrates, respectively. The ionic liquid-based polymer gel electrolyte is prepared by combining the ionic liquid 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate ([Py_1,4]TfO), with Zn(TfO)₂ and poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP). The ionic liquid polymer gel electrolyte exhibits good conductivity (2.2 mS cm^?1) and good mechanical stability. Zinc deposition and stripping in the ionic liquid polymer gel electrolyte were studied by cyclic voltammetry, potentiostatic, and galvanostatic cycling (charging/discharging) experiments. The gel electrolyte exhibits a promising electrochemical stability and allows a quasi-reversible zinc deposition/stripping. The morphology of the zinc deposits after 10 cycles of zinc deposition/stripping is compact and dense, and deposits without any dendrite formation can be obtained. The quasi-reversibility of the electrochemical deposition/stripping of zinc in this ionic liquid polymer gel electrolyte is of interest for rechargeable zinc-based batteries.     

Dominant ion transport processes of ionic liquid electrolyte in poly(3,4-ethylenedioxythiophene)

Electrochemical quartz crystal microgravimetry was used to study movement of the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIBTI) into and out of poly(3,4-ethylenedioxythiophene) (PEDOT). In 0.1M EMIBTI/acetonitrile, anionic transport predominates, as is typical of solution-based electrolytes. In pure EMIBTI, on the other hand, the minimal mass change observed during polymer oxidation/reduction was observed to be cation-dominant. PEDOT deposition from dilute EMIBTI solution followed by cycling in neat EMIBTI resulted in rapid decrease of electroactivity. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013     

Enhanced zinc ion transport in gel polymer electrolyte: effect of nano-sized ZnO dispersion

The effect of the dispersion of zinc oxide (ZnO) nanoparticles in the zinc ion conducting gel polymer electrolyte is studied. Changes in the morphology/structure of the gel polymer electrolyte with the introduction of ZnO particles are distinctly observed using X-ray diffraction and scanning electron microscopy. The nanocomposites offer ionic conductivity values of >10^?3 S cm^?1 with good thermal and electrochemical stabilities. The variation of ionic conductivity with temperature follows the Vogel–Tamman–Fulcher behavior. AC impedance spectroscopy, cyclic voltammetry, and transport number measurements have confirmed Zn²⁺ ion conduction in the gel nanocomposites. An electrochemical stability window from ?2.25 to 2.25 V was obtained from voltammetric studies of nanocomposite films. The cationic (i.e., Zn²⁺ ion) transport number (t ₊) has been found to be significantly enhanced up to a maximum of 0.55 for the dispersion of 10 wt.% ZnO nanoparticles, indicating substantial enhancement in Zn²⁺ ion conductivity. The gel polymer electrolyte nanocomposite films with enhanced Zn²⁺ ion conductivity are useful as separators and electrolytes in Zn rechargeable batteries and other electrochemical applications.     

A novel polymer gel electrolyte: Direct polymerization of ionic liquid from surface of silica nanoparticles

A novel polymer electrolyte is synthesized by directly grafting poly ionic liquids onto silica nanoparticles. The kinetic study of this surface‐initiated polymerization has also been included. A gel‐state electrolyte is formed by mixing this type of polymer/silica nanocomposite with ionic liquids under 60 °C, which exhibits an excellent conductivity of 0.8 mS/cm at room temperature and 14.7 mS/cm at 90 °C. In addition, the mechanism of gel formation has also been discussed in this article. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 121–127     

Properties of a nanocomposite polymer electrolyte from an amorphous comb-branch polymer and nanoparticles

Three fully amorphous comb-branch polymers based on poly(styrene-co-maleic anhydride) as a backbone and poly(ethylene glycol) methyl ether of different molecular weights as side chains were synthesized. SiO₂ nanoparticles of various contents and the salt LiCF₃SO₃ were added to these comb-branch polymers to obtain nanocomposite polymer electrolytes. The thermal and transport properties of the samples have been characterized. The maximum conductivity of 2.8×10^–4 S cm^–1 is obtained at 28 °C. In the system the longer side chain of the comb-branch polymer electrolyte increases in ionic conductivity after the addition of nanoparticles. To account for the role of the ceramic fillers in the nanocomposite polymer electrolyte, a model based on a fully amorphous comb-branch polymer matrix in enhancing transport properties of Li⁺ ions is proposed.     

Synthesis of Fe3O4, Fe2O3, Ag/Fe3O4 and Ag/Fe2O3 nanoparticles and their electrocatalytic properties

Two important iron oxides:Fe3O4 and Fe2O3,as well as Fe3O4 and Fe2O3 nanoparticles mingling with Ag were successfully synthesized via a hydrothermal procedure.The samples were confirmed and characterized by X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).The morphology of the samples was observed by transmission electron microscopy(TEM).The results indicated Fe3O4,Fe2O3,Ag/Fe3O4 and Ag/Fe2O3 samples all were nanoparticles with smaller sizes.The samples were modified on a glassy carbon electrode and their elctrocatalytic properties for p-nitrophenol in a basic solution were investigated.The results revealed all the samples showed enhanced catalytic performances by comparison with a bare glassy carbon electrode.Furthermore,p-nitrophenol could be reduced at a lower peak potential or a higher peak current on a glassy carbon electrode modified with Ag/Fe3O4 or Ag/Fe2O3 composite nanoparticles.     

Oxygen ionic transport in Bi2O3-based oxides: The solid solutions Bi2O3–Nb2O5

The minimum concentration of niobium to stabilize the fluorite-type f.c.c. phase in the Bi₂O₃–Nb₂O₅ oxide system at temperatures below 996 K was ascertained to be about 10 mol%. Thermal expansion, electrical conductivity and crystal lattice parameters of the Bi(Nb)O_1.5+δ solid solutions decrease with increasing niobium content. Thermal expansion coefficients were calculated from the dilatometric data to be (10.314.5)×10⁻⁶ K⁻¹ at temperatures in the range 300–700 K and (17.526.0)×10⁻⁶ K⁻¹ at 700–1100 K. The conductivity of the Bi_{1− x} Nb _x O_1.5+δ ceramics is predominantly ionic. The p-type electronic transference numbers of the Bi(Nb)O_1.5+δ solid solutions in air were determined to be less than 0.1. Annealing at temperatures below 900 K results in a sharp decrease in conductivity of the Bi_{1− x} Nb _x O_1.5+δ ceramics. Received: 18 August 1997 / Accepted: 20 October 1997     

Study on the adsorption of DNA on Fe3O4 nanoparticles and on ionic liquid-modified Fe3O4 nanoparticles

We have investigated the adsorption of herring sperm DNA on Fe₃O₄ magnetic nanoparticles (NPs) before and after modification with the ionic liquid 1-hexyl-3-methylimidazolium bromide. Experiments were performed in a batch mode, and the effects of DNA concentration, pH of the sample solution, ionic strength, temperature, and contact time between reagents were optimized. An evaluation of the adsorption isotherm revealed that the Langmuir model better fits the equilibrium data than the Freundlich model. The maximum adsorption capacities of the unmodified and modified NPs, respectively, were found to be 11.8 and 19.8 mg DNA per gram of adsorbent. The adsorption of DNA onto the modified NPs was endothermic, while it was exothermic in the case of the unmodified NPs. The DNA can be desorbed from the modified surfaces of the NPs by using EDTA as the eluent. The NPs were able to adsorb about 90?±?1.5 % of DNA after being recycled for three times. The method is simple, fast, robust, and does not require organic solvents or sophisticated equipment.