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1.
Poly(ethylene glycol)/poly(2-acrylamido-2-methyl-1-propane sulfonic acid) (PEG/PAMPS) with a transparent appearance were prepared in the presence of ammonium persulfate (APS) as an initiator at 70 °C for 24 h. PEG/PAMPS-based polymer gel electrolytes in a motionless and uniform state were obtained by adding the required amount of liquid electrolytes to a dry PEG/PAMPS polymer. Liquid electrolytes include organic solvents with high boiling points (-1-methyl-2-pyrrolidone (NMP) and γ-butyrolactone (GBL)) and a redox couple (alkali metal iodide salt/iodine). The optimized conditions for PEG/PAMPS-based gel electrolytes based on the salt type, the concentration of alkali metal iodide salt/iodine, and solvent volume ratio were determined to be NaI, 0.4 M NaI/0.04 M I2, and NMP:GBL (7:3, v/v), respectively. The highest ionic conductivity and the liquid electrolyte absorbency were 2.58 mS cm?1 and 3.6 g g?1 at 25 °C, respectively. The ion transport mechanism in both the polymer gel electrolytes and liquid electrolytes is investigated extensively, and their best fits with respect to the temperature dependence of the ionic conductivity are determined with the Arrhenius equation.  相似文献   

2.
A. K. Nath  A. Kumar 《Ionics》2013,19(10):1393-1403
Ionic conductivity and transport properties of polyvinylidenefluoride–co-hexafluoropropylene– montmorillonite intercalated nanocomposite electrolytes based on ionic liquid 1-butyl-3-methylimidazolium bromide have been studied for various concentrations of montmorillonite clay. Ionic conductivity of the order of 10?3?S?cm?1 at room temperature with thermal stability up to about 235 °C has been obtained for the electrolyte system. The electrolyte system has superior properties at 5 wt% of clay loading with highly amorphous morphology as seen from selected area electron diffraction micrograph. Scanning electron microscope studies show that the electrolyte system has highly porous morphology and the ionic liquid is trapped in the pores. Dielectric properties of the electrolyte system have been studied to investigate the relaxation processes occurring in the system. Variation of real part of dielectric permittivity with frequency shows two relaxation processes occurring in the system, slow at low frequency and fast at high frequency. Kohlrausch exponential parameter has been calculated from modulus formalism, and the values show that the distribution of conductivity relaxation times becomes narrower with increasing clay loading.  相似文献   

3.
Rajiv Kumar  S. S. Sekhon 《Ionics》2013,19(11):1627-1635
The addition of polymer to liquid electrolytes containing trifluoromethanesulfonic acid (HCF3SO3) in propylene carbonate (PC) has been found to result in an increase in conductivity of gel electrolytes. The increase in conductivity has been observed to be due to the dissociation of ion aggregates present in the electrolytes which has also been supported by Fourier transform infrared studies. The maximum ionic conductivity (at 25 °C) of 7.55?×?10?3 S/cm has been observed for polymer gel electrolytes containing 1.5 wt% polymethylmethacrylate in 0.5 M solution of HCF3SO3 in PC. Polymer gel electrolytes have been found to be thermally stable up to a temperature of 125 °C by simultaneous differential scanning calorimetry/thermogravimetric analysis studies. The conductivity of polymer gel electrolytes does not show any appreciable change over a limited period of time.  相似文献   

4.
Poly(ethylene oxide)(PEO)–poly(vinyl alcohol) (PVA) blend-based gel polymer electrolytes (GPEs) have been prepared by blending equal weights of PEO and PVA in ethylene carbonate (EC), dimethyl sulfoxide (DMSO), tetrabutylammonium iodide (TBAI), and iodine crystals (I2). The conductivity, diffusion coefficient, number density, and ion mobility of the electrolytes have been calculated from the impedance data obtained from electrochemical impedance spectroscopy (EIS) measurements. The GPE with the composition of 7.02 wt%, PVA, 7.02 wt% PEO, 30.11 wt% ethylene carbonate (EC), 30.11 wt% DMSO, 24.08 wt% TBAI and 1.66 wt% I2 exhibits the highest conductivity of 5.5 mS cm?1 at room temperature. Dye-sensitized solar cells (DSSCs) with configuration fluorine tin oxide (FTO)/titanium dioxide/N3-dye/GPE/platinum/FTO have been fabricated and tested under the white light of intensity 100 mW cm?2. The DSSC containing the highest conducting GPE exhibits the highest power conversion efficiency, η of 5.36 %.  相似文献   

5.
A. K. Nath  A. Kumar 《Ionics》2014,20(12):1711-1721
Swift heavy ion (SHI) irradiation has been used as a tool to enhance the electrochemical properties of ionic liquid-based nanocomposite polymer electrolytes dispersed with dedoped polyaniline (PAni) nanorods; 100 MeV Si9+ ions with four different fluences of 5?×?1010, 1?×?1011, 5?×?1011, and 1?×?1012 ions cm?2 have been used as SHI. XRD results depict that with increasing ion fluence, crystallinity decreases due to chain scission up to fluence of 5?×?1011 ions cm?2, and at higher fluence, crystallinity increases due to cross-linking of polymer chains. Ionic conductivity, electrochemical stability, and dielectric properties are enhanced with increasing ion fluence attaining maximum value at the fluence of 5?×?1011 ions cm?2 and subsequently decrease. Optimum ionic conductivity of 1.5?×?10?2 S cm?1 and electrochemical stability up to 6.3 V have been obtained at the fluence of 5?×?1011 ions cm?2. Ac conductivity studies show that ion conduction takes place through hopping of ions from one coordination site to the other. On SHI irradiation, amorphicity of the polymer matrix increases resulting in increased segmental motion which facilitates ion hopping leading to an increase in ionic conductivity. Thermogravimetric analysis (TGA) measurements show that SHI-irradiated nanocomposite polymer electrolytes are thermally stable up to 240–260 °C.  相似文献   

6.
Polypyrrole/graphene sheets (PPy/GNs) nanocomposite electrodes were in- situ synthesized via electrochemical polymerization and chemical reduction from pyrrole (Py) and graphene oxide (GO). The surface morphologies of the nanocomposites were observed by scanning electron microscopy (SEM). The SEM results showed graphene sheets (GNs) scattered on the surface of the polypyrrole (PPy), and the morphologies of PPy/GNs nanocomposites manufactured by pulse current (PC-PPy/GNs) or direct current (DC-PPy/GNs) were smoother than that of PC-PPy. The electrochemical capacitance properties of the nanocomposite films were measured by cyclic voltammetry (CV), galvanostatic charge and discharge (GC), and electrochemical impedance spectroscopy (EIS) techniques in 3 mol·L?1 KCl aqueous solutions. The results indicated that the specific capacitance of the DC-PPy/GNs nanocomposite was 13.5% higher than that of a PC-PPy electrode. Comparison of the electrochemical performance of the nanocomposites indicated that the PC-PPy/GNs nanocomposite had higher specific capacitance and better charging/discharging capability than that of the DC-PPy/GNs nanocomposite. The specific capacitance of the PC-PPy/GNs nanocomposite could reach to 280 F·g?1 at a scanning rate of 100 mV·s?1.  相似文献   

7.
In the present work, a series of five different nanocomposite polymer electrolytes (NCPEs) have been reported with varying contents of ceria, CeO2 nanofiller suitably incorporated within an optimized composition having 75:25 wt% ratio of poly(vinylidenefluoride-co-hexafluoropropylene) [(PVDF-co-HFP)] and zinc trifluoromethanesulfonate (ZnTf) in the form of films obtained by mean of solution casting technique with a general formula [75 wt% PVDF-co-HFP:25 wt% ZnTf]-x wt% CeO2 where x = 1, 3, 5, 7, and 10, respectively. The chosen NCPE system is found to exhibit the maximum electrical conductivity of 3 × 10?4 S cm?1 for 5 wt% loading of CeO2 nanofiller at ambient temperature. The observed conductivity enhancement has been attributed to the occurrence of an increase in the amorphous content as confirmed by X-ray diffraction (XRD) analysis. Detailed Fourier transform infrared (FTIR) spectral analysis has indicated the feasibility of complexation of the host polymer matrix with ZnTf salt and CeO2 nanofiller. The incorporation of CeO2 nanofiller has further increased the decomposition voltage of the polymer electrolyte from 2.4 to 2.7 V as revealed from the voltammetric studies performed on such NCPEs, thereby suggesting the suitability of these NCPE films with an enhanced electrical conductivity as new electrolytes in order to design and fabricate eco-friendly zinc rechargeable batteries and other electrochemical devices.  相似文献   

8.
Yingqiong Yong  Li-Zhen Fan 《Ionics》2013,19(11):1545-1549
Silicon/carbon nanocomposites are prepared by dispersing nano-sized silicon in mesophase pitch and a subsequent pyrolysis process. In the nanocomposites, silicon nanoparticles are homogeneously distributed in the carbon networks derived from the mesophase pitch. The silicon/carbon nanocomposite delivers a high reversible capacity of 841 mAh g?1 at the current density of 100 mA g?1 at the first cycle, high capacity retention of 98 % over 30 cycles, and good rate performance. The superior electrochemical performance of nanocomposite is attributed to the carbon networks with turbostratic structure, which enhance the conductivity and alleviate the volume change of silicon.  相似文献   

9.
A series of gel polymer electrolytes (GPEs) containing lithium bis(oxalato)borate (LiBOB), propylene carbonate (PC), and ethylene carbonate (EC) have been investigated. Poly(ethylene oxide) (PEO) was used as the polymer. First, a series of liquid electrolytes was prepared by varying the Li:O ratio and obtained the best composition giving the highest conductivity of 7.1?×?10?3 S cm?1 at room temperature. Then, the PEO-based GPEs were prepared by adding different amounts of LiBOB and PEO into a mixture of equal weights of EC and PC (40 % of each from the total weight). The gel electrolyte comprises of 12.5 % of LiBOB, 7.5 % of PEO, 40 % of EC, and 40 % of PC gave the highest ionic conductivity of 5.8?×?10?3 S cm?1 at room temperature. From the DC polarization measurements, ionic nature of the gel electrolyte was confirmed. Fourier transform infrared (FTIR) spectra of electrolytes showed the Li+ ion coordination with EC and PC molecules. These interactions were exhibited in the peaks corresponding to ring breathing of EC at 893 cm?1 and ring bending of EC and symmetric ring deformation of PC at 712 and 716 cm?1 respectively. The presence of free Li+ ions and ion aggregates is evident in the peaks due to the symmetric stretching of O–B–O at 985 cm?1.  相似文献   

10.
The composition dependence of plasticizer (ethylenecarbonate(EC)/dimethyl carbonate(DMC))(70?x)wt% to Lithium bis(perfluoroethanesulfonyl)imide(LIBETI)(x)wt% salt (where x?=?1.5, 3.0, 4.5, 6.0 wt%) on PVdF-co-HFP (25 wt%)/surface modified octadecylamine containing montmorrillonite (ODA-MMT) nano clay (5 wt%) matrix has been investigated by AC impedance, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and dielectric and cyclic voltammetry studies. The enhanced conductivity 2.1?×?10?5 Scm?1 is noted in salt rich phase (EC/DMC)(70–6)wt% /LiBETI(x=6)wt% (VK4). In XRD, 2θ at 20.9° confirms β-phase. In FTIR studies, vibrational bands 838, 522 and 611 cm?1 confirm β-phase of PVdF due to clay intercalation. In DSC studies, the melting of α-phase crystallites is noted between 140–150 °C. In SEM studies, one of the membranes presents fern leaf texture confirming swelling of clay. The increase in dielectric constant and dielectric loss with decrease in frequency is attributed to high contribution of charge accumulation at the electrode–electrolyte interface. In cyclic voltammetry studies, salt-rich phase membrane (VK4) shows good cyclability than other membranes.  相似文献   

11.
Herein, we demonstrate a facile one-step hydrothermal synthesis route to anchor ZnO nanoparticles on nitrogen and sulfur co-doped graphene sheets. The detailed material and electrochemical characterization have been carried out to demonstrate the potential of novel ZnO/NSG nanocomposite in Li-ion battery (LIBs) applications. The structure and morphology of nanocomposite were assessed by X-ray diffraction (XRD), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The as-synthesized ZnO/NSG nanocomposite has been studied as anode material in LIBs and delivered a high initial discharge capacity of 1723 mAh g?1, at the current density of 200 mA g?1. After 100 cycles, the ZnO/NSG nanocomposites demonstrated a high reversible capacity of 720 mAh g?1 and coulombic efficiency of 99.8%, which can be attributed to the porous three-dimensional network, constructed by ZnO nanoparticles and nitrogen and sulfur co-doped graphene. Moreover, the designed nanocomposite has shown excellent rate capability and lower charge transfer resistance. These results are promising and encourage further research in the area of ZnO-based anodes for next-generation LIBs.  相似文献   

12.
The influence of tetrabutylammonium iodide on the polyvinylidene fluoride-poly(methyl methacrylate)-ethylene carbonate (PVDF-PMMA-EC)-I2 polymer blend electrolytes was investigated and optimized for use in a dye-sensitized solar cell. The different weight ratios (50, 60, 70, and 80 %) of tetrabutylammonium iodide (TBAI)-added PVDF-PMMA-EC-I2 polymer electrolytes were prepared. The prepared solid polymer blend electrolytes were characterized by using various techniques such as Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and electrochemical impedance spectroscopy (EIS). The FT-IR spectra revealed the interaction among all composition of polymer electrolytes. The influence of TBAI salt on the ionic conductivity of polymer electrolytes was studied using electrochemical impedance spectroscopy. The polymer electrolyte containing 60 % of TBAI in PVDF-PMMA-EC-I2 showed the highest room temperature conductivity of 5.10?×?10?3 S cm?1. The fabricated DSSC using PVDF-PMMA-EC-I2 polymer electrolytes with 60 % of TBAI showed the best performance with a short-circuit current density of 8.0 mA cm?2, open-circuit voltage of 0.66 V, fill factor of 0.65, and the overall power conversion efficiency of 3.45 % under an illumination of 100 mW cm?2. Hence, the weight content of organic iodide salt in polymer electrolytes influences the overall performance of dye-sensitized solar cells.  相似文献   

13.
High molecular weight polymer poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP), ionic liquid 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIMFSI), and salt lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)-based free-standing and conducting ionic liquid-based gel polymer electrolytes (ILGPE) have been prepared by solution cast method. Thermal, electrical, and electrochemical properties of 80 wt% IL containing gel polymer electrolyte (GPE) are investigated by thermogravimetric (TGA), impedance spectroscopy, linear sweep voltammetry (LSV), and cyclic voltammetry (CV). The 80 wt% IL containing GPE shows good thermal stability (~?200 °C), ionic conductivity (6.42?×?10?4 S cm?1), lithium ion conductivity (1.40?×?10?4 S cm?1 at 30 °C), and wide electrochemical stability window (~?4.10 V versus Li/Li+ at 30 °C). Furthermore, the surface of LiFePO4 cathode material was modified by graphene oxide, with smooth and uniform coating layer, as confirmed by scanning electron microscopy (SEM), and with element content, as confirmed by energy dispersive X-ray (EDX) spectrum. The graphene oxide-coated LiFePO4 cathode shows improved electrochemical performance with a good charge-discharge capacity and cyclic stability up to 50 cycles at 1C rate, as compared with the without coated LiFePO4. At 30 °C, the discharge capacity reaches a maximum value of 104.50 and 95.0 mAh g?1 for graphene oxide-coated LiFePO4 and without coated LiFePO4 at 1C rate respectively. These results indicated improved electrochemical performance of pristine LiFePO4 cathode after coating with graphene oxide.  相似文献   

14.
Hossein Farsi  Zahra Barzgari 《Ionics》2013,19(10):1349-1357
In this work, nanostructured tungsten oxide was electrodeposited by cyclic voltammetric technique onto a stainless steel surface. The structure and surface morphology of the resulting oxide film were characterized by means of X-ray diffraction, scanning probe microscopy, and scanning electron microscopy. The electrochemical intercalation of lithium into the nanostructured tungsten oxide was studied using cyclic voltammetry, galvanostatic charge–discharge curves, and electrochemical impedance spectroscopy in a liquid electrolyte consisting of 1 M LiClO4 in propylene carbonate. The as-deposited tungsten oxide indicated the capacity for electrochemical lithium insertion. The specific capacitance of 108.05 F?g?1 was obtained at the constant discharge density of 0.07 mA?cm?2.  相似文献   

15.
Lithium ion-conducting membranes with poly(ethylene oxide) (PEO)/poly(vinylidene chloride-co-acrylonitrile) (PVdC-co-AN)/lithium perchlorate (LiClO4) were prepared by solution casting method. Different plasticizers ethylene carbonate (EC), propylene carbonate (PC), gamma butyrolactone (gBL), diethyl carbonate (DEC), dimethyl carbonate (DMC), and dibutyl phthalate (DBP) were complexed with the fixed ratio of PEO/PVdC-co-AN/LiClO4. The preparation and physical and electrochemical properties of the gel polymer electrolytes have been briefly elucidated in this paper. The maximum ionic conductivity value computed from the ac impedance spectroscopy is found to be 3?×?10?4 S cm?1 for the EC-based system. From DBP-based system down to EC-based system, a decrease of crystallinity and an increase of amorphousity are depicted by X-ray diffraction technique, the decrease of band gap energy is picturized through UV–visible analysis, the decrease of glass transition temperature is perceived from differential scanning calorimetry plots, and the reduction of photoluminescence intensity is described through photoluminescence spectroscopy study at an excitation wavelength of 280 nm. Atomic force microscopic images of EC-based polymer electrolyte film show the escalation of micropores. Fourier transform infrared spectroscopy study supports the complex formation and the interaction between the polymers, salt, and plasticizer. The maximum thermal stability is obtained from thermogravimetry/differential thermal analysis, which is found to be 222 °C for the sample complexed with EC. The cyclic voltagram of the sample having a maximum ionic conductivity shows a small redox current at the anode, and cathode and the chemical stability is confirmed by linear sweep voltammetry.  相似文献   

16.
Magnesium (Mg) electrolytes are presently under investigation for their promising performance capabilities in the next generation of batteries. The present work studies Mg-ion transport in polymers using different types of Mg salts. Polymer electrolytes comprising poly(ethylene carbonate) (PEC) with Mg salts (MgX2; X?=?TFSI, ClO4) were prepared by solution casting. The structural, thermal, and electrochemical properties of flexible self-standing membranes were studied as potential Mg electrolytes. The impedance results at 90 °C found the highest conductivities of 6.0?×?10?6 S cm?1 for PEC-Mg(TFSI)2, and 5.2?×?10?5 S cm?1 for PEC-Mg(ClO4)2, at 40 mol%. FT-IR measurements revealed changes in the peak fraction from the region of carbonyl group, which explain the interaction with Mg ions. The glass transition temperature of the TFSI system decreased with increasing salt concentration due to the plasticizing effect of TFSI anions. Thermal gravimetric analysis revealed that the highest values of the 5% weight-loss temperature at 40 mol% are 174 °C for PEC-Mg(TFSI)2 and 160 °C for PEC-Mg(ClO4)2. The electrochemical stability of PEC-Mg(TFSI)2 at 40 mol% was up to 2.2 V. To confirm the redox reaction of Mg ions in PEC, CV measurement was carried out using symmetrical cells with quasi Mg electrodes. Cathodic and anodic current peaks were clearly observed, and the presence of these peaks indicates Mg-ion conduction in PEC.  相似文献   

17.
Nanocomposites of montmorillonite (MMT) with poly(1‐naphthylamine) (PNA) is investigated for the first time by emulsion polymerization using three different oxidants. Polymerization of PNA was confirmed by Fourier transformation infrared (FT‐IR) as well as UV‐visible spectra. The in situ intercalative polymerization of PNA within MMT layers was confirmed by FT‐IR, X‐ray diffraction, conductivity; scanning electron microscopy (SEM) as well as transmission electron microscopy studies. X‐ray diffraction revealed intercalated as well as exfoliated structures of PNA/MMT nanocomposites, which were compared with the reported polyaniline‐MMT nanocomposites. It was found that the increase in the concentration of PNA in the interlayer galleries of MMT led to destruction of the layered clay structure resulting in exfoliation of the nanocomposite. Conductivity of the nanocomposites was found to be in the range of 10?3 to 10?2 S cm?1 which was found to be higher than the ones reported for polyaniline‐clay nanocomposites as well as PEOA‐OMMT nanocomposites at similar concentrations of intercalated species. The morphology of PNA/MMT nanocomposites was found to be governed by the nature of the oxidant used.  相似文献   

18.
Two systems (salted and plasticized) of starch–chitosan blend-based electrolytes incorporated with ammonium chloride (NH4Cl) are prepared via solution cast technique. The incorporation of 25 wt% NH4Cl has maximized the room temperature conductivity of the electrolyte to (6.47?±?1.30)?×?10?7 S cm?1. Conductivity is enhanced to (5.11?±?1.60)?×?10?4 S cm?1 on addition of 35 wt% glycerol. The temperature dependence of conductivity for all electrolytes is Arrhenian, and the value of activation energy (E a ) decreases with increasing conductivity. Conductivity is found to be influenced by the number density (n) and mobility (μ) of ions. The complexation between the electrolytes components is proven by Fourier transform infrared analysis. The relaxation time (t r ) for selected electrolytes is found to decrease with increasing conductivity and temperature. Conduction mechanism for the highest conducting electrolyte in salted and plasticized systems is determined by employing Jonscher’s universal power law.  相似文献   

19.
Solid polymer polyethylene glycol (PEG)-based electrolytes composed with zinc acetate Zn(CH3COO)2 have been prepared by using solution blending. We proposed a scheme of PEG–zinc acetate for battery application. The structure confirmation was done by using X-ray diffraction studies detecting the phase variation. The thermal properties demonstrate the optimization of melting point (T m) as a function of loading zinc acetate. The impedance analysis reveals that the role of ionic conductivity depends on the controlled concentration of Zn(CH3COO)2. Optimum ionic conductivity σ?~?1.55?×?10?6 S?cm?1 at room temperature (303 K) was observed for 70:30 composition. The linear variation in log σ vs 1000/T plot is based on the Arrhenius-type thermally activated process. The simultaneous discharge profile was confirmed by the solid-state electrochemical cell. Hence, the PEG–zinc acetate composition was suggested for polymer electrolyte battery application.  相似文献   

20.
A series of solid polymer electrolytes (SPEs) based on poly (ethylene oxide)/polylactic acid (PEO/PLA) with liquid crystal ionomer (LCI) intercalated montmorillonite (MMT) nanocomposites (LCI-MMT) has been prepared by solution blending method. The effects of LCI-MMT on the structural, crystallization, thermal, and ionic conductivity properties of solid polymer electrolytes have been analyzed. It is demonstrated that the incorporation of LCI-MMT into the blend suppressed the crystallinity of PEO and increased the crystallinity of PLA. The maximum ionic conductivity is found to be in the range of 1.05?×?10?5 S/cm for 0.5 wt% LCI-MMT, which is higher than that of the LCI-MMT-free polymer electrolyte (5.36?×?10?6 S/cm) at room temperature.  相似文献   

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