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1.
Plasticized solid polymer electrolytes (PSPEs) consisting of poly(ethylene oxide) (PEO) and poly(methyl methacrylate) (PMMA) blend (50/50 wt%) based matrix with lithium tetrafluoroborate (LiBF4) as dopant ionic salt (10 wt%) and varied concentrations (x = 0, 5, 10 and 15 wt%) of ethylene carbonate (EC) as plasticizer have been prepared. Classical solution-cast (SC) and the ultrasonic assisted followed by microwave irradiated (US–MW) solution-cast methods have been used for the preparation of (PEO–PMMA)–LiBF4x wt% EC films, and the same have been hot–pressed to get their smooth surfaces. Dielectric relaxation spectroscopy (DRS) and X–ray diffraction (XRD) techniques have been employed to characterize the dielectric and electrical dispersions and the structural properties of the PSPE films, respectively. It has been observed that the ionic conductivity of these semicrystalline ion-dipolar complexes is governed by their dielectric permittivity and polymers chain segmental dynamics. The increase in ionic conductivity values with the increase of plasticizer concentration in the PSPEs also varies with the films’ preparation methods. The US–MW method prepared PSPE film containing 15 wt% EC has a maximum ionic conductivity (1.86 × 10?5 S cm?1) at room temperature, whereas, the films having low concentrations of EC exhibit the conductivity of the order of 10?6 S cm?1.  相似文献   

2.
Herein, a conductive polymer material containing rare earth oxide (PEG–LiX–CeO2) was designed and synthesized. The bonding performance of the conductive polymer was analyzed via AC impedance, X-ray diffraction (XRD), infrared spectroscopy (FTIR), scanning electron microscopy (SEM), tensile strength, ball milling and anodic bonding experiments. The AC impedance, XRD and FTIR experiments demonstrate that the introduction of alkali metal lithium salt and cerium oxide (CeO2) can effectively reduce the crystallinity of the composites and increase the ion migration. The results of ball milling show that increasing the milling time (<?10 h) and speed (<?250 r min?1) can improve the conductivity of the composites. The anodic bonding experiment of PEG–LiClO4–CeO2 with AL foil and the SEM characterization of the bonding interface demonstrate the existence of a well-defined bonding layer between the bonding interface.  相似文献   

3.
The study presents preparation of poly methyl methacrylate (PMMA) based nanocomposite gel polymer electrolytes consisting of, salt lithium perchlorate (LiClO4), plasticizer PC/DEC and different proportions of SiO2 nanofiber by solution casting process. The effect of the composition of the electrolytes on their ionic, mechanical and thermal characteristics was investigated. Morphology of the nanocomposite electrolyte films has been observed by scanning and transmission electron microscopes. Interactions among the constituents of the composite and structural changes of the base polymer were investigated by Fourier Transform Infrared (FTIR) spectroscopy and X-ray diffraction (XRD) techniques. The maximum conductivity i.e. 10?3 Scm?1 at room temperature is obtained with the electrolyte composition of 0.6(PMMA)-0.15(PC + DEC)-0.1LiClO4 (wt%) containing 10 wt% SiO2 nanofiber and the temperature dependent conductivity data of the electrolyte follows Vogel-Tamman-Fulcher (VTF) behavior.  相似文献   

4.
Sodium lithium sulfide (NaLiS) nanocomposite have been successfully synthesized by using microwave-irradiation (MWI) method. The study suggested that the application of microwave heating is to produce homogeneous and fine NaLiS nanocomposite which were achieved by using the precursors of lithium acetate and thioacetamide in the presence of sodium alginate biopolymer. FTIR is used to identify the structural coordination and functional groups of the prepared nanocomposite. The structural property of NaLiS particles was investigated by XRD. The surface morphology and elemental composition of synthesized material was confirmed by SEM and EDX analyses. The optical property was studied by using UV–Vis spectrophotometer. Thermal stability of as prepared sample was studied by TGA/DTG analysis. Electrical transport studies of the prepared nanocomposite have been analyzed for various temperatures. NaLiS nanocomposite has ionic conductivity of ~?10?7 S cm?1 at 35 °C which is six orders of magnitude higher than that of micro sized bulk Li2S (~?10?13 S cm?1).  相似文献   

5.
The polymer electrolytes comprising of PVdF-HFP/PVAc/Mg(ClO4)2 as salt based polymer blend electrolytes derived from the addition of varying amounts of 1-ethyl – 3-methylimidazolium trifluoromethane sulfonate [EMITF], as dopant were synthesized in the form of films by solution-casting method. The XRD and FTIR patterns confirm the formation of an amorphous phase and also that complex formation between the polymers, salt and ionic liquid. The SEM images show that the polymer electrolyte exhibit a enormous pores, remarkably, the maximum ionic conductivity is obtained in the case of the typical polymer system I3 is found to be 9.122 × 10?4 Scm?1at 303 K.  相似文献   

6.
There has been an increasing interest in synthesizing the novel composite polymer electrolyte (CPE) for use in lithium batteries in recent years. This paper describes the preparation and characterization of CPE containing lithium perchlorate based on polyindole–NiO nanocomposite. NiO nanoparticles were added to the monomer solution before the polymer formation in the presence of a surfactant to get the PInNiO nanocomposite. The thermal properties, surface morphology, and structural studies of the electrolyte were investigated by TGA, SEM, TEM, and XRD. An enhanced conductivity of 2.62 × 10?4 S cm?1 at 45°C for the composite polymer electrolyte was determined from impedance studies.  相似文献   

7.
Poly(vinyl chloride) (PVC)—poly(butyl methacrylate) (PBMA) blended polymer electrolytes with lithium perchlorate (LiClO4) as the complexing salts are prepared by solution casting technique. The addition of PBMA into PVC matrix is found to induce considerable changes in physical and electrical properties of the polymer electrolytes. Addition of PBMA into PVC matrix is found to increase the conductivity by two orders of magnitude (1.108 × 10?5 S cm?1) when compared with that of the pristine PVC polymer electrolyte (10?7 S cm?1). Structural, thermal, mechanical, morphological, and polymer–salt interactions are ascertained from X‐ray diffraction (XRD), thermogravimetry/differential thermal analysis (TG/DTA), mechanical analysis, scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) respectively. A thermal stability upto 250 °C is asserted from the TG/DTA analysis. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44939.  相似文献   

8.
Polymer gel electrolytes comprising a sulfur-based ionic liquid (IL), a lithium salt, and butyrolactone (GBL) as an additive hosted in PVdF-HFP matrix were prepared and characterized. The result shows that adding small amount of GBL to the polymer electrolytes can improve the cathodic stability of the electrolytes, which ensures the lithium plating/stripping in the redox process. Furthermore, cyclic voltammograms studies indicate that the polymer electrolytes have well reversible redox process. When the IL component reaches 75 wt%, the polymer electrolyte has higher ionic conductivity than the other samples and it is 6.32 × 10?4 S cm?1. The assembled batteries with the polymer electrolyte have better discharge capacity, and after 100 cycles, the discharge capacity of the battery still retains 148 mAh g?1.  相似文献   

9.
The synthesis and characterization of conducting polyaniline (PANI) salt and nickel sulfide (NiS) hybrid composites are reported in this study. The PANI-NiS hybrid composites showed nearly two orders of magnitude higher than that of pure PANI. The specific conductivities of PANI and PANI-NiS hybrid composites (2% and 20% by weight) were found to be 5.1 × 10?4, 1.6 × 10?2, and 3.8 × 10?2 S/cm. The polarity of Hall voltage of the hybrid composite was found to be negative indicating that the PANI-NiS composite is an n-type semiconductor. The composites pellets were characterized by XRD, SEM and FTIR and the results were compared.  相似文献   

10.
A series of novel plasticized nanocomposite solid polymer electrolytes (PNCSPE) consisting of polyethylene oxide as polymer host, lithium bisoxalatoborate as salt with different weight ratios of succinonitrile and nano-hydroxyapatite was prepared by membrane hot-press technique. The electrical property of PNCSPE was investigated by AC impedance analysis. The migration of lithium ion in the polymer matrix was confirmed from cyclic voltammetry study. The incorporation of different compositions of filler and plasticizer in the polymer matrix significantly enhanced the amorphous nature resulted in increase in ionic conductivity of PNCSPE. The maximum ionic conductivity was found to be in the order of 10?3.1 S/cm.  相似文献   

11.
A facile route was adopted to blend the matrix. The PMMA/PEG blend was reinforced with three types of nanofillers, i.e., pristine MWCNT (P-CNT), amine functionalized MWCNT (PDA-EA-CNT) and nanobifiller i.e. nanodiamond functional MWCNT (PDA-EA-CNT-ND) to yield three different types of nanocomposites i.e. PMMA/PEG/P-CNT, PMMA/PEG/PDA-EA-CNT and PMMA/PEG/PDA-EA-CNT-ND. These nanocomposites were reinforced with nanofiller loading (1 wt. %, 3 wt. %, 5 wt. %, 10 wt. %, 30 wt. % and 50 wt. %) by solution casting method. Structure of composite and nanofillers was confirmed by FTIR. FESEM imaging revealed that nanocomposites have micro porous morphology. At high magnification, distribution of functionalized CNT/ND appears to be protruding out of the polymeric matrix. The TGA result suggests that the thermal stability of the nanocomposites was enhanced in comparison to PMMA due to grafting of filler molecules with PMMA/PEG macromolecules. The DTG results showed that the bifiller nanocomposites (PMMA/PEG/PDA-EA-CNT-ND) exhibited improved thermal stability with Tmax (431°C) as compared to P-CNT and amine functionalized CNT (PMMA/PEG/PDA-EA-CNT) with Tmax of 395°C and 418°C respectively. XRD results showed fine interaction between filler and the polymeric matrix. As the filler loading was increased the composites showed pronounced XRD peak at 25.9°, corresponding to (002) reflection of nanotubes. Significant improvement in the mechanical properties of composites was recorded with the reinforcement of fillers as compared to the neat matrix. The most significant improvement in tensile strength and elastic modulus was observed for the bifiller nanocomposites with 5 wt. % PDA-EA-CNT-ND. They showed a tensile strength and elastic modulus of 29.9 MPa and 1474.31 MPa respectively as compared to amine functionalized CNT with tensile strength (25.7) and elastic modulus (1466.99 MPa)and P-CNT with tensile strength(25 MPa) and elastic modulus (1155.75 MPa).  相似文献   

12.
Polymethylmethacrylate (PMMA) materials are extensively used for diverse applications e.g., protective vehicular windows to eye protection devices. However, the high strain rate deformation and fracture mechanisms of PMMA are far from well understood. Therefore, controlled split Hopkinson pressure bar (SHPB) experiments that could lead to deformation with and without fracture were conducted on PMMA samples at strain rates of ~4 × 100 to 1.3 × 103 s?1. With increase in strain rate, the maximum compressive yield strength of PMMA is enhanced by about 25 %. Absence of global failure characterized the deformation at relatively lower strain rates (e.g., ~4.75 × 102 to 6.75 × 102 s?1), while its marked presence characterized the same at comparatively higher strain rates (e.g., ~7.69 × 102 to 9.31 × 102 s?1). Attempts were made to explain these observations by the subtle changes in failure mechanisms as revealed from the fractographic examinations of the PMMA samples deformed with and without failures. The implications of the test-condition induced restrictions on the degrees of freedom locally available to the polymeric chains were discussed in the perspective of the relative strain rate dependencies of the yield behaviors of the present PMMA samples.  相似文献   

13.
The electrochemical performance of lithium–sulfur batteries with LiClO4 DOL/DME as electrolyte was investigated. Impedance and SEM analysis indicated that too high content of DME(Dimethoxy ethane) in electrolyte could raise the interfacial resistance of battery due to the impermeable layer formed on the surface of the sulfur cathode, which led to bad cycle performance, while the increase of DOL(1,3-dioxolane) could change those phenomena. The optimal composition of electrolyte was DME:DOL = 2:1 (v/v). With this electrolyte, the lithium–sulfur battery obtained a high initial discharge capacity of 1,200 mA h g?1 and still remained 800 mA h g?1 after 20 cycles.  相似文献   

14.
The lithium‐ion conducting gel polymer electrolytes (GPE), PVAc‐DMF‐LiClO4 of various compositions have been prepared by solution casting technique. 1H NMR results reveal the existence of DMF in the gel polymer electrolytes at ambient temperature. Structure and surface morphology characterization have been studied by X‐ray diffraction analysis (XRD) and scanning electron microscopy (SEM) measurements. Thermal and conductivity behavior of polymer‐ and plasticizer‐salt complexes have been studied by differential scanning calorimetry (DSC), TG/DTA, and impedance spectroscopy results. XRD and SEM analyses indicate the amorphous nature of the gel polymer‐salt complex. DSC measurements show a decrease in Tg with the increase in DMF concentrations. The thermal stability of the PVAc : DMF : LiClO4 gel polymer electrolytes has been found to be in the range of (30–60°C). The dc conductivity of gel polymer electrolytes, obtained from impedance spectra, has been found to vary between 7.6 × 10?7 and 4.1 × 10?4 S cm?1 at 303 K depending on the concentration of DMF (10–20 wt %) in the polymer electrolytes. The temperature dependence of conductivity of the polymer electrolyte complexes appears to obey the VTF behavior. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   

15.
A novel and sensitive electrochemical sensor based on the cone conformation of the supramolecule 25, 27-(3-thiopropoxy)-p-tert-butyl calix[4]arene has been developed for quantitative determination of polycyclic aromatic hydrocarbons (PAHs). The method works effectively by immobilizing calix[4]arenes on Fe3O4 magnetic nanoparticles. CdSe quantum dots were used as electrochemical labels. CdSe quantum dots (QDs) modified PAHs in competition with the sample PAHs were intercalated into calix[4]arenes supramolecules via a host–guest interaction through individual bowl-shaped calix[4]arenes. The stripping analysis of the cadmium dissolved from CdSe nanoparticles provided a sensitive method for the detection of PAHs in the samples. The signal decrease of the QDs was proportional to the increase in the concentration of the PAHs. Under optimal conditions, among the five PAHs, the square wave voltammetry (SWV) response of QDs decreased linearly for anthracene and naphthalene in the range of 2.1 × 10?7–1.4 × 10?5 and 1.5 × 10?6–2.5 × 10?5 M, respectively. The calculated detection limits (3δ) were 20.1 ng mL?1 for anthracene and 105.5 ng mL?1 for naphthalene.  相似文献   

16.
Various kinds of nano-SiO2 using different catalysts were obtained and characterized by scanning electron microscope (SEM) technique. The results showed that the nano-SiO2 using NH3·H2O as catalyst presented the best morphology. Poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP) based composite polymer electrolyte (CPE) membranes doped with different contents of nano-SiO2 were prepared by phase inversion method. The as-prepared CPE membranes were immersed into 1.0 M LiPF6-EC/DMC/EMC electrolytes for 0.5 h to be activated. The physicochemical and electrochemical properties of the CPEs were characterized by SEM, X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV) techniques. The results indicate that the CPEs doped with 10 % nano-SiO2 exhibit the best performance. SEM micrographs showed that the CPE membranes have uniform surface with abundant interconnected micro-pores, and the uptake ratio was up to 104.4 wt%. EIS and LSV analysis also showed that the ionic conductivity at room temperature and electrochemical stability window of the modified membrane can reach 3.372 mS cm?1 and 4.7 V, respectively. The interfacial resistance R i was 670 Ω cm?2 in the first day, then increased to a stable value of about 850 Ω cm?2 in 10 days storage at room temperature. The Li/As-fabricated CPEs/LiCoO2 cell also showed good charge–discharge performance, which suggested that the prepared CPE membranes can be used as potential electrolytes for lithium ion batteries.  相似文献   

17.
Fe (III)-loaded chitosan (CS) hollow fibers (CS-Fe (III) HF) were successfully prepared according to the dry-wet spinning technique. The CS-Fe (III) HFs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analysis (TGA). Removal of pentavalent arsenic was studied through biosorption on CS-Fe (III) HF adsorptive membranes. The response surface methodology (RSM) was applied to investigate the influence of the main operating parameters such as contact time, pH, initial As (V) concentration and HFs dosage on the adsorption capacity of As (V). From the Pareto analysis, pH, [As (V)]o, [CS-Fe (III) HF membranes] and squared effect of [As(V)]o were found to produce the largest effect on biosorption of As (V). Kinetic studies showed that the pseudo-second-order kinetic model provides the best correlation to the experimental results. Equilibrium data fitted well with the Langmuir model with maximum adsorption capacity of 3,703 μg g?1. A laboratory scale glass membrane module consisting of three CS-Fe(III) HFs has also been prepared and tested for biosorption of As (V) at a real scale. Permeability of As (V) ions through the CS-Fe (III) HF membranes was 0.145 μmol m?2 h?1 bar ?1.  相似文献   

18.
In this work, high electrically conductive Polymethylmethacrylate/graphite (PMMA/G) composites with a specific core-shell structure were synthesized via Pickering emulsion (solid-stabilized emulsion) route. The electrical conductivity of the core-shell composites was measured by a four-point probe resistivity determiner and a very high value of 9.8?×?10?3 S/cm (1013 times higher than virgin PMMA) was obtained at 30 wt% graphite. However, the electrical conductivity of the PMMA/G composites gained through traditional blend process was relatively lower and the value only reached 9.4?×?10?9 S/cm at same graphite loading fraction. Contact angle measurement was applied to determine the surface free energy of the modified graphite which was cladded by Al(OH)3. The morphology of the core-shell composites was observed by SEM and optical microscopy. Dynamic rheology analysis was employed to study the structural change by the interconnection of the graphite flakes and the formation of the networks in the composites. The interconnected networks of the core-shell composites were more easily constructed when compared with the composites obtained by the traditional blending process.  相似文献   

19.
The kinetics of oxidation of ruthenium(III) (Ru(III)) and osmium(VIII) (Os(VIII)) catalysed oxidation of L-phenylalanine (L-Pal) by diperiodatoargentate(III) (DPA) in aqueous alkaline medium at 27 °C and a constant ionic strength of 0.25 mol dm?3 was studied spectrophotometrically. The involvement of free radicals was observed in the reactions. The reaction between DPA and L-Pal in alkaline medium exhibits stoichiometry as [L-Pal]:[DPA] = 1:1. The reaction is of first order in [Os(VIII)], [Ru(III)] and [DPA] and has negative fractional order in [IO4 ?]. It has less than unit order in [L-Pal] and [OH?]. However, the order in [L-Pal] and [OH?] changes from first order to zero order as their concentrations increase. The main oxidation products were identified by spot test and spectral studies. The probable mechanisms were proposed and discussed. The catalytic constant (K c) was also calculated for Os(VIII) and Ru(III) catalysis at different temperatures. The activation parameters with respect to slow step of the mechanisms were computed and discussed and thermodynamic quantities were also calculated. It has been observed that the catalytic efficiency for the present reaction is in the order of Os(VIII) > Ru(III). The active species of catalyst and oxidant have been identified.  相似文献   

20.
In this study, the charge efficiency, nucleation growth, and morphology of electrodeposited copper from spent Li-batteries were studied. The charge efficiency for these deposits shows a maximum value of 99.41%, under a charge density of 5.0 C cm?2. Studies with the SEM technique at pH 2.0 show well-formed nuclei. At pH 4.5, the deposits take the form of dendrites. XRD analysis shows that, in both cases, a Cu2O structure is present, but with a large amount at pH 4.5, evidenced by peaks of [002] and [110] directions.  相似文献   

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