Nanocomposite blend gel polymer electrolyte for proton battery application

A proton-conducting nanocomposite gel polymer electrolyte (GPE) system, [35{(25 poly(methylmethacrylate) (PMMA) + 75 poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP))?+?xSiO₂}?+?65{1 M NH₄SCN in ethylene carbonate (EC) + propylene carbonate (PC)}], where x?=?0, 1, 2, 4, 6, 8, 10, and 12, has been reported. The free standing films of the gel electrolyte are obtained by solution cast technique. Films exhibit an amorphous and porous structure as observed from X-ray diffractometry (XRD) and scanning electron microscopy (SEM) studies. Fourier transform infrared spectrophotometry (FTIR) studies indicate ion–filler–polymer interactions in the nanocomposite blend GPE. The room temperature ionic conductivity of the gel electrolyte has been measured with different silica concentrations. The maximum ionic conductivity at room temperature has been observed as 4.3?×?10^?3?S?cm^?1 with 2 wt.% of SiO₂ dispersion. The temperature dependence of ionic conductivity shows a typical Vogel-Tamman-Fulcher (VTF) behavior. The electrochemical potential window of the nanocomposite GPE film has been observed between ?1.6 V and 1.6 V. The optimized composition of the gel electrolyte has been used to fabricate a proton battery with Zn/ZnSO₄·7H₂O anode and PbO₂/V₂O₅ cathode. The open circuit voltage (OCV) of the battery has been obtained as 1.55 V. The highest energy density of the cell has been obtained as 6.11 Wh?kg^?1 for low current drain. The battery shows rechargeability up to 3 cycles and thereafter, its discharge capacity fades away substantially.     

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.     

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.     

ZnO nanoparticles and poly(acrylic) acid-based polymer gel electrolyte for photo electrochemical cell

This work presents a photo electrochemical cell based on zinc oxide (ZnO) nanoparticles and poly(acrylic) acid (PAA) doped with sodium iodide (NaI) and iodine (I₂) polymer gel electrolyte. The ZnO powders were synthesized by sol–gel storage and sol–gel centrifugation. The ZnO powder synthesized via sol–gel centrifugation showed the optimal structural properties, with largest crystallite sizes of 58 nm, average particles size between 20 and 80 nm and indirect band gap energy of 3.20 eV. The highest conductivity [(8.0 ± 0.1) × 10^?2 S cm^?1] was obtained for PAA + 0.8 M NaI + 0.02 M I₂. This sample achieved the lowest activation energy (0.029 eV) and electrochemical stability at 1.6 V. The ZnO powder synthesized via sol–gel centrifugation and PAA + 0.8 M NaI + 0.02 M I₂ was fabricated as a Cu–ZnO/PAA + 0.8 M NaI + 0.02 M I₂/C-ITO photo electrochemical cell.     

Magnesium ion-conducting gel polymer electrolytes dispersed with fumed silica for rechargeable magnesium battery application

Effect of fumed silica dispersion on poly(vinylidene fluoride-co-hexafluoropropylene)-based magnesium ion-conducting gel polymer electrolyte has been studied using various physical and electrochemical techniques. The composite gel electrolytes are free-standing and flexible films with enough mechanical strength. The optimized composition with 3 wt.% filler offers a maximum ionic conductivity of ∼1.1 × 10⁻² S cm⁻¹ at ∼25 °C with good thermal and electrochemical stabilities. The Mg²⁺ ion conduction in the gel nanocomposite film is confirmed from the cyclic voltammetry, impedance spectroscopy, and transport number measurements. The space-charge layers formed between filler particles and gel electrolyte are responsible for the enhancement in ionic conductivity. The applicability of the gel nanocomposite to a rechargeable battery is examined by fabricating a prototype cell consisting of Mg [or Mg-multiwalled carbon nanotube (MWCNT) composite] and MoO₃ as negative and positive electrodes, respectively. The discharge capacity and the rechargeability of the cell have been improved when Mg metal is substituted by Mg-MWCNT composite. The discharge capacity of the optimized cell has found to be ∼175 mAh g⁻¹ of MoO₃ for an initial ten charge–discharge cycles.     

Cross-linking copolymers of acrylates’ gel electrolytes with high conductivity for lithium-ion batteries

The cross-linking gel copolymer electrolytes containing alkyl acrylates, triethylene glycol dimethacrylate, and liquid electrolyte were prepared by in situ thermal polymerization. The gel polymer electrolytes containing 15 wt% polymer content and 85 wt% liquid electrolyte content with sufficient mechanical strength showed the high ionic conductivity around 5?×?10^?3 Scm^?1 at room temperature. The gel electrolytes containing different polymer matrices were prepared, and their physical observation and conductivity were discussed carefully. The cross-linking copolymer gel electrolytes of alkyl acrylates with other monomers were designed and synthesized. The results showed that copolymerization can improve the mechanical properties and ionic conductivities of the gel electrolytes. The polymer matrices of gels had excellent thermal stability and electrochemical stability. The scanning electron microscope analysis showed the gel electrolyte was the homogeneous structure, and the cross-linking polymer host was the porous three-dimensional network structure, which demonstrated the high conductivity of the gel electrolytes. The gel polymer Li-ion battery was prepared by this in situ thermal polymerization. The cell exhibited high charge-discharge efficiency at 0.1 C. The results of LiFePO4-PEA-Li cell and graphite-PEA-Li cell showed that gel polymer electrolytes have good compatibility with the battery electrodes materials.     

Dielectric and conductivity studies of 90 MeV O7+ ion irradiated poly(ethylene oxide)/montmorillonite based ion conductor

In the present work effect of 90 MeV O⁷⁺ ions with five different fluences on poly(ethylene oxide) (PEO)/Na⁺-montmorillonite (MMT) nanocomposites has been investigated. PEO/MMT nanocomposites were synthesized by solution intercalation technique. With the increase in irradiation fluence, gallery spacing of MMT increases in the composite and an exfoliated nanostructure is obtained at the fluence of 5?×?10¹² ions/cm² as revealed by X-ray diffraction results. Highest room temperature ionic conductivity of 4.2?×?10^?6?S?cm^?1 was found for the fluence 5?×?10¹² ions/cm², while the conductivity for unirradiated polymer electrolyte was found to be 7.5?×?10^-8?S?cm^?1. The increase in intercalation of PEO chains inside the galleries of MMT results in the increase in interaction between Na⁺ cation and oxygen heteroatom leading to the increase in ionic conductivity of the composites. Surface morphology and interactions among the various constituents in the nanocomposites at different fluence have been examined by scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. The appearance of peak for each fluence in the loss tangent suggests the presence of relaxing dipoles in the polymer nanocomposite electrolyte films. With the increase in ion fluence the peak shifts towards higher frequency side, suggesting decrease in the relaxation time.     

室温离子液体增塑的纳米复合聚合物电解质研究

在室温离子液体N-乙基-N'-甲基咪唑四氟硼酸盐(EMIBF₄)增塑的凝胶聚合物电解质中加入氧化铝纳米粒子, 制备了一种纳米复合聚合物电解质(nanocomposite polymer electrolyte, NCPE). 通过示差扫描量热(DSC)、X射线衍射(XRD)、热重分析(TGA)、电化学阻抗谱(EIS)等手段对其进行了表征. 结果显示, 随着氧化铝纳米粒子含量的增加, NCPE的结晶度降低, 离子导电率升高. 但是, 纳米粒子的加入量过大时反而引起NCPE的离子导电率降低. 当纳米粒子填充量为w＝10%时, NCPE具有最高的室温离子导电率1.25×10^－3 S•cm^－1.     

Effect of solvents on properties of polymer gel-electrolyte based on polyester diacrylate

New polymer gel electrolytes based on polyester diacrylates and LiClO₄ salt solutions in organic solvents are developed for lithium ion and lithium polymer batteries with a high ionic conductivity up to 2.7 × 10^?3 Ohm^?1cm^?1 at the room temperature. To choose the optimum liquid electrolyte composition, the dependence is studied of physico-chemical parameters of new gel electrolytes on the composition of the mixture of aprotic organic solvents: ethylene carbonate, propylene carbonate, and λ-butyrolacton. The bulk conductivity of gel electrolytes and exchange currents at the gel electrolyte/Li interface are studied using the electrochemical impedance method in symmetrical cells with two Li electrodes. The glass transition temperature and gel homogeneity are determined using the method of differential scanning calorimetry. It is found that the optimum mixture is that of propylene carbonate and λ-butyrolacton, in which a homogeneous polymer gel is formed in a wide temperature range of ?150 to +50°C.     

PVDF/PAN/SiO<Subscript>2</Subscript> polymer electrolyte membrane prepared by combination of phase inversion and chemical reaction method for lithium ion batteries

PVDF/PAN/SiO₂ polymer electrolyte membranes based on non-woven fabrics were prepared via introducing a chemical reaction into Loeb-Sourirajan (L-S) phase inversion process. It was found that physical properties (porosity, electrolyte uptake and ionic conductivity) and electrochemical properties were obviously improved. A favorable membrane structure with fully connective porous and uniform pore size distribution was obtained. The effects of PVDF/PAN weight ratio on the morphology, crystallinity, porosity, and electrochemical performances of membranes were studied. The optimized PVDF/PAN (70/30 w/w) (designated as M_pc30) polymer electrolyte membrane delivered excellent electrolyte uptake of 246.8 % and the highest ionic conductivity of 3.32 × 10^?3 S/cm with electrochemical stability up to 5.0 V (vs. Li/Li⁺). In terms of cell performance, the Li/M_pc30 polymer electrolyte/LiFePO₄ battery exhibited satisfactory electrochemical properties including high discharge capacity of 149 mAh/g at 0.2 C rate and good discharge performance at different current densities. The promising results reported here clearly indicated that PVDF/PAN/SiO₂ polymer electrolyte membranes prepared by the combination of phase inversion and chemical reaction method were promising enough to be applied in power lithium ion batteries.     

Improving electrochemical performance of poly(vinyl butyral)-based electrolyte by reinforcement with network of ceramic nanofillers

This study has concerned the development of polymer composite electrolytes based on poly(vinyl butyral) (PVB) reinforced with calcinated Li/titania (CLT) for use as an electrolyte in electrochemical devices. The primary aim of this work was to verify our concept of applying CLT-based fillers in a form of nano-backbone to enhance the performance of a solid electrolyte system. To introduce the network of CLT into the PVB matrix, gelatin was used as a sacrificial polymer matrix for the implementation of in situ sol–gel reactions. The gelatin/Li/titania nanofiber films with various lithium perchlorate (LiClO₄) and titanium isopropoxide proportions were initially fabricated via electrospinning, and ionic conductivities of electrospun nanofibers were then examined at 25 °C. In this regard, the highest ionic conductivity of 2.55 × 10⁻⁶ S/cm was achieved when 10 wt% and 7.5 wt% loadings of LiClO₄ and titania precursor were used, respectively. The nanofiber film was then calcined at 400 °C to remove gelatin, and the obtained CLT film was then re-dispersed in solvated PVB-lithium bis(trifluoromethanesulfonyl)imide (PVB-LiTFSI) solution before casting to obtain reinforced composite solid electrolyte film. The reinforced composite PVB polymer electrolyte film shows high ionic conductivity of 2.22 × 10⁻⁴ S/cm with a wider electrochemical stability window in comparison to the one without nanofillers.

     

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     

Hypergrafted nano-silica modified polymer gel electrolyte for high-performance solid-state supercapacitor

In the developing of wearable electronics and smart textiles, thin, lightweight, and flexible energy storage supercapacitor with high energy density has attracted the attention of many researchers in recent years. In this work, we prepared gel nano-composite electrolyte with the hypergrafted poly (amine-ester) nano-silica (HBPAE-SiO₂) as inclusion. The electrochemical properties of the supercapacitor with the alkaline polymer electrolyte were evaluated by cyclic voltammetry, galvanostatic charge–discharge behavior, and electrochemical impedance spectroscopy. It was found that the incorporated HBPAE-SiO₂ can greatly increase the specific capacitance of the supercapacitor, which was due to the enhanced ionic conductivity of gel electrolyte as well as good electrode–electrolyte contact. It is pointed out that the electroactivity of the inclusion may be also one reason. The best specific capacitance with 30 wt% HBPAE-SiO₂ reached 160 F g^?1, which was increased by 36.5 % compared with that of polyvinyl alcohol (PVA)-KOH system. Moreover, the capacity retention of solid-state supercapacitor can be 88 % after 10,000 cycles. The hypergrafted nano-silica modified polymer gel electrolyte is promising for the application of solid-state supercapacitor.     

Novel potentiometric sensor for the trace-level determination of Zn2+ based on a new nanographene/ion imprinted polymer composite

In this research, a new strategy for construction of a development potentiometric carbon paste Zn²⁺-ion selective electrode based on a novel nano-sensing layer is suggested. The proposed nano-sensing layer was prepared with the addition of a synthesised Zn²⁺-ion imprinted polymer nanoparticles ‘as an efficient sensing agent’ into the carbon paste matrix consisting of graphite powder, nanographene-composite ‘graphene nanosheets decorated with silver nanoparticles’ and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ‘ an ionic liquid ’, as the conducting binder. Under the optimised experimental conditions, the suggested nanographene-composite potentiometric sensor presented a low detection limit of 1.93 × 10^?1 μg L^?1 and a linear analytical range from 2.62 × 10^?1 to 6.54 × 10⁵ μg L^?1 with an excellent Nernstian slope of 29.80 mV decade^?1. The proposed zinc selective sensor was successfully applied for the highly sensitive determination of trace amounts of Zn²⁺ in environmental and biological samples with satisfactory results.     

Influence of barium titanate nanofiller on PEO/PVdF-HFP blend-based polymer electrolyte membrane for Li-battery applications

Organic-inorganic hybrid membranes based on poly(ethylene oxide) (PEO) 6.25 wt%/poly(vinylidene fluoride hexa fluoro propylene) [P(VdF-HFP)] 18.75 wt% were prepared by using various concentration of nanosized barium titanate (BaTiO₃) filler. Structural characterizations were made by X-ray diffraction and Fourier transform infrared spectroscopy, which indicate the inclusion of BaTiO₃ in to the polymer matrix. Addition of filler creates an effective route of polymer-filler interface and promotes the ionic conductivity of the membranes. From the ionic conductivity results, 6 wt% of BaTiO₃-incorporated composite polymer electrolyte (CPE) showed the highest ionic conductivity (6 × 10^?3 Scm^?1 at room temperature). It is found that the filler content above 6 wt% rendered the membranes less conducting. Morphological images reveal that the ceramic filler was embedded over the membrane. Thermogravimetric and differential thermal analysis (TG-DTA) of the CPE sample with 6 wt% of the BaTiO₃ shows high thermal stability. Electrochemical performance of the composite polymer electrolyte was studied in LiFePO₄/CPE/Li coin cell. Charge-discharge cycle has been performed for the film exhibiting higher conductivity. These properties of the nanocomposite electrolyte are suitable for Li-batteries.     

Electrospun octa(3-chloropropyl)-polyhedral oligomeric silsesquioxane-modified polyvinylidene fluoride/poly(acrylonitrile)/poly(methylmethacrylate) gel polymer electrolyte for high-performance lithium ion battery

Gel polymer electrolyte (GPE) based on octa(3-chloropropyl)-polyhedral oligomeric silsesquioxane (OCP-POSS)-modified polyvinylidene fluoride/poly(acrylonitrile) /poly(methylmethacrylate) (PVDF/PAN/PMMA) fibrous membrane was prepared by electrospinning method to improve the thermal stability of GPE and prevent the leakage of liquid electrolyte for lithium ion battery. The effect of OCP-POSS content on the morphology, porosity and electrolyte uptake, mechanical strength, thermal stability of spinning fibrous membrane and ionic conductivity, electrochemical stability window, and interface resistance of GPE was investigated. The cycle performance of cells assembled with GPE was also tested. The results show that the spinning fibrous membrane with 10 wt% OCP-POSS possesses high electrolyte uptake (660%) and excellent thermal stability. The ionic conductivity of corresponding GPE is 9.23 × 10^?3 S cm^?1 at room temperature and the electrochemical stability window is up to 5.82 V; the interface resistance of 10 wt% OCP-POSS modified GPE decreases by 42% after 168 h compared with pure PVDF/PAN/PMMA GPE. Furthermore, cells assembled with 10 wt% OCP-POSS modified GPE show high discharge capacity (166.5 mA h g^?1 at 0.1 C) and excellent cycle stability during 50 cycles. The results indicate that the GPE could improve the safety of lithium ion battery and show great potential in lithium ion battery applications.     

Electrochemical polymerization of polyaniline doped with Zn2+ as the electrode material for electrochemical supercapacitors

Polyaniline doped with Zn²⁺ (PANI/Zn²⁺) films was synthesized by cyclic voltammetric method on stainless steel mesh substrates in 0.2 mol L^?1 aniline and 0.5 mol L^?1 sulfuric acid electrolyte with various concentrations of zinc sulfate (ZnSO₄·7H₂O). The structure and morphology of PANI and PANI/Zn²⁺ films were characterized by Fourier transform infrared, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy techniques, respectively. The electrochemical properties of PANI and PANI/Zn²⁺ films were investigated by cyclic voltammetry, galvanostatic charge–discharge test, and electrochemical impedance spectroscopy in 0.5 mol L^?1 H₂SO₄ electrolyte in a three-electrode system. The results show that the surface morphology of PANI/Zn²⁺ is more rough than that of pure PANI. The specific capacitance of the PANI/Zn²⁺ film displays a larger specific capacitance of 738 F g^?1, lower resistance, and better stability as compared with the pure PANI film. Thus, good capacitive performance demonstrates its potential superiority for supercapacitors.     

Mg-ion conducting gel polymer electrolyte membranes containing biodegradable chitosan: Preparation,structural, electrical and electrochemical properties

A biodegradable gel polymer electrolyte system based on chitosan/magnesium trifluoromethanesulfonate/1-ethyl-3-methylimidazolium trifluoromethanesulfonate (CA/Mg (Tf)₂/EMITf) is developed. The structure, thermal performance, mechanical properties, ionic conductivity, relaxation time, electrochemical stability and ionic transport number of the membranes are analyzed by various techniques. The ion migration mainly depends on the complexation and decomplexation of Mg²⁺ with amine band (NH₂) in chitosan. The 90CA-10Mg (Tf)₂ system plasticized with 10% EMITf (relative to the amount of 90CA-10Mg (Tf)₂) is identified as the optimum one and the temperature dependence of ionic conductivity obeys the Arrhenius rule. Moreover, the relaxation time of the electrolyte is very short, being just 1.25 × 10⁻⁶ s, and its electrochemical stability window is quite wide, being up to 4.15 V. The anodic oxidation and cathodic reduction of Mg at the Mg-electrode/electrolyte interface is facile, and the ionic transference number of this electrolyte is 0.985, indicating that it could be a potential electrolyte candidate for Mg-ion devices.     

Influence of solvent type on porosity structure and properties of polymer separator for the Li-ion batteries

Polyethylene-supported polymethyl methacrylate/poly(vinylidene fluoride-co-hexafluoropropylene) separator for gel polymer lithium-ion battery use was prepared with a mixed solvent of n-butanol and acetone. The prepared separator was characterized with scanning electron spectroscopy and X-ray diffraction, and its performance was investigated by electrochemical impedance spectroscopy and battery charge/discharge test. Compared to the separator prepared with acetone, the separator prepared with the mixed solvent shows an enhanced porosity (from 42 to 49 %) and electrolyte uptake (from 104 to 125 %). The ionic conductivity of the corresponding gel polymer electrolyte is improved from 2.81 to 3.39 mS cm^?1, the discharge capacity retention of the LiCoO₂/artificial graphite battery is increased from 95 to 98 % after 100 cycles at 0.5 C, and the discharge capacity of the battery at 1 C increases by 4 %.     

Different morphologies of ZnO nanostructures via polymeric complex sol–gel method: synthesis and characterization

Various morphologies of ZnO nanostructures, such as nanoparticles, nanorods and nanoflowers have been achieved controllably by polymeric sol–gel method. In this approach, zinc nitrate Zn(NO₃)₂·6H₂O, citric acid and ethylene glycol were used as the source of Zn²⁺, the chelating agent and the solvent agent, respectively. The microstructure of the ZnO nanostructures was characterized by X-ray diffractometry, scanning electron microscopy with the energy dispersive X-ray spectroscopy, transmission electron microscopy, thermogravimetric analysis and Fourier transform infrared spectroscopy. The effect of ethylene glycol to citric acid mole ratio on the morphology and structure of the products was discussed. The ZnO nanoparticles with diameter between 24 ± 2 nm was obtained with EG:CA mole ratio equal to 2:1. The optical properties of as-obtained power were investigated by ultraviolet–visible spectroscopy.