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1.
The specific features of the synthesis and the physicochemical properties of new nanocomposite polymer electrolytes (NPE) based on poly(ethylene glycol) diacrylate, a liquid electrolyte, and silicon dioxide were studied. The kinetics of polymerization of the system in question were studied by isothermal calorimetry and the optimal conditions for the hardening of the NPE were selected. The dependence of the conductivity of the electrolyte samples on the amount of SiO 2 nanopowder introduced, the presence of preliminary ultrasonic treatment of the nanocomposite mixture before the synthesis, and the storage duration of the samples was studied using the electrochemical impedance method. The maximum conductivity (4.3?10 –3 S cm –1 at 20 °C) was observed for samples without preliminary treatment with the introduction of 6 wt.% of SiO 2 and for the samples after ultrasonic treatment with 8 wt.% of SiO 2. The electrolyte films with the optimal SiO 2 content of 4 wt.% maintained their properties for 24 months. 相似文献
2.
Nanocomposite polymer electrolytes based on polyethylene glycol diacrylate and 1 M LiBF 4 solution in γ-butyrolactone with addition of SiO 2 nanoparticles were synthesized and studied. Resistance measurement at the Li/electrolyte and Li/nanocomposite electrolyte interface by the time-resolved electrochemical impedance showed its significant decrease in the presence of SiO 2 nanoparticles. Charge-discharge cycling of prototypes of Li/LiFePO 4 batteries for 50 cycles also showed the advantage of using nanocomposite polymer electrolytes over electrolytes without SiO 2 additives. 相似文献
3.
Network polymer electrolytes based on poly(ester diacrylate), LiClO 4, and ethylene carbonate are synthesized and investigated via the methods of electrochemical impedance spectroscopy, DSC,
and thermal analysis. It is found that, for the polymer-LiClO 4 system, the conductivity is 4.2 × 10 −7 S/cm at 20°C. With a gradual increase in the amount of ethylene carbonate, the conductivity first decreases and then increases.
It is shown that, when poly(ester diacrylate) is crosslinked in ethylene carbonate, up to 45.5% of the latter compound is
retained in the polymer and not lost during heating to 100°C. The conductivity of the electrolyte containing 45.6 wt % poly(ester
diacrylate), 45.5 wt % ethylene carbonate, 7.5 wt % LiClO 4, and 1.4 wt % benzoyl peroxide achieves 1.9 × 10 −4 S/cm at 20°C. 相似文献
4.
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 Zn 2+ 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., Zn 2+ 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 Zn 2+ ion conductivity. The gel polymer electrolyte nanocomposite films with enhanced Zn 2+ ion conductivity are useful as separators and electrolytes in Zn rechargeable batteries and other electrochemical applications. 相似文献
5.
Electrochromic devices are fabricated by using polyaniline (PANI) doped with poly(styrene sulfonic acid) (PSS) as coloring electrodes, poly(ethylenedioxythiophene)‐poly(styrene sulfonic acid) (PEDOT‐PSS) as complementary electrodes, and hybrid polymer electrolytes as gel electrolytes. The device based on LiClO 4‐based electrolyte (weight ratio of PMMA:PC:LiClO 4 = 0.7:1.1:0.3) shows the highest optical contrast and coloration efficiency (333 cm 2/C) after 1200 cycles in these devices, and the color changes from pale yellow (?0.5 V) to dark blue (+2.5 V). The spectroelectrochemical and electrochromic switching properties of electrochromic devices are investigated, the maximum optical contrast (Δ T%) of electrochromic device for ITO|PANI‐PSS‖PMMA‐PC‐LiClO 4‐SiO 2‖PEDOT‐PSS|ITO are 31.5% at 640 nm, and electrochromic device based on LiClO 4‐based electrolyte with SiO 2 shows faster response time than that based on LiClO 4‐based electrolyte without SiO 2. 相似文献
6.
The cathodic overvoltage of composite cathodes 50 wt % La 0.8Sr 0.2MnO 3 (LSM) + 50 wt % La 10Ge 6O 27 (LGO) (further on, LSM-LGO), LSM-SSZ (Zr 0.835Sc 0.165O 2?δ), Ag-Pd-LGO, and Ag-Pd-SSZ in contact with the LGO electrolyte is measured. The temperature dependences of the polarization conductivity and the working-current densities of the same composite cathodes are investigated. The study is performed at 700–900°C. A comparison with the SSZ electrolyte is conducted. The chemical interaction in the LSM-LGO composition is studied. It is demonstrated that the interaction of lanthanum-strontium manganite with lanthanum germanate occurs with the dissolution of the initial phases in one another and with the formation of fresh phases at elevated temperatures. Coefficients of linear thermal expansion of the LGO and SSZ electrolytes and the LSM, LSM-LGO, and LSM-SSZ electrode materials are compared at 40–900°C. Most of the studied electrodes in contact with the LGO electrolyte demonstrate thermomechanical stability and high electrochemical activity. 相似文献
7.
Nanocomposite polymer electrolytes based on poly(ethylene glycol) diacrylate and 1 M LiBF4 solution in γ-butyrolactone containing SiO2 nanoparticles were studied by FT IR spectroscopy. Quantum chemical modeling of five different solvate complexes of ions composed of LiBF4 with solvent molecules was carried out and their theoretical IR spectra were calculated. The compositions of the solvate complexes of LiBF4 in the nanocomposite gel electrolyte were studied by comparing the experimental and theoretical IR spectra. It was concluded that the conductivity peak observed upon adding 2 wt.% SiO2 is due to the appearance of mobile ions as a consequence of ionic dissociation on the surface of nanoparticles at their optimal configuration. 相似文献
8.
Stabilization of oil-in-water Pickering emulsions with SiO 2 and Fe 3O 4 nanoparticles has been studied. Emulsions containing three-dimensional gel networks formed by aggregated nanoparticles in the dispersion media have been shown to be stable with respect to flocculation, coalescence, and creaming. Concentration ranges in which emulsions are kinetically stable have been determined. Stabilization with mixed Ludox HS-30 and Ludox CL SiO 2 nanoparticles leads to the formation of stable emulsions at a weight ratio between the nanoparticles equal to 2 and pH 6.7. In the case of stabilization with Ludox CL and Fe 3O 4 nanoparticles, systems resistant to aggregation and sedimentation are obtained at pH 8. The use of mixed Ludox HS-30 and Fe 3O 4 nanoparticles has not resulted in the formation of emulsions stable with respect to creaming, with such emulsions appearing to be resistant only to coalescence at pH 2–6. 相似文献
9.
An electrochemical cell of potentiometric type Na 0.5WO 3 (reference electrode)/Na +-solid electrolyte/PbS (working electrode) capable of rapid and selective changing of the electromotive force value owing
to H 2S concentration variations in gas surroundings has been investigated at 295±1 K and a relative humidity of 52%. The sensitivity
of this cell was 130 mV/decade at a H 2S concentration within the range 13–130 ppm. Sodium-conducting solid electrolytes of Na 3Zr 2Si 2PO 12 and Na 5GdSi 4O 12 compositions were used as the Na + solid electrolyte. Such a cell can be used for analysis of H 2S containing water solutions when the reference electrode and the Na + solid electrolyte are thoroughly isolated from the surroundings.
Electronic Publication 相似文献
10.
The samples of the NiO/B 2O 3-Al 2O 3 system with NiO contents from 0.48 to 38.30 wt % were synthesized by the impregnation of borate-containing alumina (20 wt
% B 2O 3). It was found that nickel oxide occurred in an X-ray amorphous state in the samples containing to 23.20 wt % NiO. At a NiO
content of 4.86 wt % or higher, the support was blocked by the modifier to cause a decrease in the specific surface area from
234 to 176 m 2/g and in the amount of acid sites from 409–424 to 333 μmol/g. An extremal character of the dependence of catalyst activity
in ethylene oligomerization on NiO content was found with a maximum in the range of 4.86–9.31 wt %. Based on spectroscopic
data, it was found that ethylene activation on the NiO/B 2O 3-Al 2O 3 catalyst can be associated with the presence of Ni 2+ cations, which chemically interact with the support. The catalyst containing 4.86 wt % NiO at 200°C, a pressure of 4 MPa,
and an ethylene supply rate of 1.1 h −1 provided almost complete ethylene conversion at the yield of liquid oligomerization products to 90.0 wt %; the total concentration
of C 8+ alkenes in these products was 89.0 wt %. 相似文献
11.
Anodic oxidation of highly oriented pyrolytic graphite in an electrolyte containing concentrated sulfuric and anhydrous phosphoric acids is studied for the first time. The synthesis was carried out under galvanostatic conditions at a current I = 0.5 mA and an elevated temperature ( t = 80°C). Intercalation compounds of graphite (ICG) are shown to form at all concentration ratios of H 2SO 4 and H 3PO 4 acids. The intercalation compound of step I forms in solutions containing more than 80 wt % H 2SO 4, a mixture of compounds of intercalation steps I and II forms in 60% H 2SO 4, intercalation step II is realized in the sulfuric acid concentration range from 10 to 40%, and a mixture of compounds of intercalation steps III and II is formed in 5% H 2SO 4 solutions. The threshold concentration of H 2SO 4 intercalation is ∼2%. With the decrease in active intercalate (H 2SO 4) concentration, the charging curves are gradually smoothed, the intercalation step number increases, and the potentials of ICG formation also increase. As the sulfuric acid concentration in the electrolyte changes from 96 to 40 wt %, the filled-layer thickness d
i in ICG monotonously increases from 0.803 to 0.820 nm, which apparently is associated with the greater size of phosphoric acid molecules. With further increase in H 3PO 4 concentration in solution, d
i remains unchanged. According to the results of chemical analysis, both acids are simultaneously incorporated into the graphite interplanar spacing and their ratio in ICG is determined by the electrolyte composition.__________Translated from Elektrokhimiya, Vol. 41, No. 5, 2005, pp. 651–655.Original Russian Text Copyright © 2005 by Leshin, Sorokina, Avdeev. 相似文献
12.
Peculiarities of electrochemical behavior of the Fe 3O 4 magnetic nanoparticles immobilized on the surface of a platinum electrode in aprotic organic media were investigated. Possible scheme of electrochemical behavior of nanoparticles depending on pre-electrolysis potential (–1.3,–2.5 V) was suggested. The effect of pre-electrolysis time, potential scan rate and nature of supporting electrolyte on the processes investigated was determined. A linear dependence of electrochemical oxidation signal versus the concentration of nanoparticles in modifying suspension in the concentration range of 0.05—0.5 g L –1 was observed. The results of the performed research allow using magnetite nanoparticles as a direct signal-generating label in electrochemical immunoassay. 相似文献
13.
Cross-linked gel polymer electrolytes containing aluminum oxide nanoparticles are successfully prepared using in-situ chemical cross-linking at room temperature after injection of the gel precursor into a dye-sensitized solar cell (DSSC). This makes it possible to directly solidify the electrolyte in the cell without leakage of solvent and to maintain close interfacial contact with the porous TiO 2 electrode. The quasi-solid-state DSSC assembled with gel polymer electrolyte containing 20 wt.% Al 2O 3 particles yields an overall conversion efficiency of 5.25% under AM 1.5 illumination at 100 mW cm − 2. 相似文献
14.
PVDF/PAN/SiO 2 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/LiFePO 4 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/SiO 2 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. 相似文献
15.
Composite membranes based on polyvinyl chloride and acrylonitrile butadiene styrene (ABS) copolymer have been prepared and then filled with 2–8 wt % of silica nanoparticles. Membranes were fabricated by solution casting method using dimethylacetamide. The performance of prepared membranes were studied for methane and ethane at the feed pressure of 1.0, 1.5, 2.0, and 3.0 bar at 35°C. By increasing the percentage of ABS, permeability of methane and ethane increased. In addition, by adding the silica nanoparticles in the membrane, permeability of gas increased in all cases. The highest gas pair selectivity for C 2H 6/CH 4 could be obtained from PVC/BS (20 wt %) which loaded with 8 wt % of silica nanoparticles. The results of this study suggest that high performance gas separation nanocomposite membranes can be attained by adopting a judicious combination of blending technique for polymeric membrane, optimized loading percentage, and feed operating conditions. 相似文献
16.
Vanadium pentoxide (V 2O 5) nanofibers (NFs) with a thin carbon layer of 3–5 nm, which wrapped on V 2O 5 nanoparticles, and integrated multiwalled carbon nanotubes (MWCNTs) have been fabricated via simple electrospinning followed by carbonization process and post-sintering treatment. The obtained composite displays a NF structure with V 2O 5 nanoparticles connected to each other, and good electrochemical performance: delivering initial capacity of 320 mAh g ?1 (between 2.0 and 4.0 V vs. Li/Li +), good cycling stability (223 mAh g ?1 after 50 cycles), and good rate performance (~?150 mAh g ?1 at 2 A g ?1). This can attribute to the carbon wrapped on the V 2O 5 nanoparticles which can not only enhance the electric conductivity to decrease the impendence of the cathode materials but also maintain the structural stability to protect the nanostructure from the corruption of electrolyte and the strain stress due to the Li-ion intercalation/deintercalation during the charge/discharge process. And, the added MWCNTs play the role of framework of the unique V 2O 5 coated by carbon layer and composited with MWCNT NFs (V 2O 5/C@MWCNT NFs) to ensure the material is more stable. 相似文献
17.
The mechanical and morphological characteristics of PA6/ABS (60/40)-based hybrid composite containing HNO 3-treated short carbon fibers (HSCF) and CaCO 3 nanoparticles have been experimentally studied. A counter-rotating twin-screw extruder and an injection molding machine were employed to produce different samples containing 10 wt % of HSCF and 0, 2, 5 and 8 wt % of CaCO 3 nanoparticles. The SEM observations indicated high-quality adhesion between HNO 3-surface treated carbon fibers and PA6/ABS polymer matrix. In addition, the morphological studies showed that the inclusion of CaCO 3 nanoparticles caused a significant effect on the ABS particle dispersion in PA6/ABS matrix. The mechanical properties assessments revealed that the incorporation of 10 wt % HSCF into the PA6/ABS can significantly improve tensile strength (82%), tensile modulus (107%), flexural strength (98%), flexural modulus (104%) and impact resistance (24%). The inclusion of CaCO 3 nanoparticles, in the presence of 10 wt % HSCF, led to the noticeable improvements of tensile strength (128% for 2 wt % CaCO 3), tensile modulus (199% for 5 wt % CaCO 3), flexural strength (146% for 5 wt % CaCO 3), flexural modulus (204% for 5 wt % CaCO 3) and impact resistance (46% for 2 wt % CaCO 3). The surface treatment of carbon fibers, dispersion conditions of nanoparticles and ABS phase in polymeric matrix were found to be the major important factors affecting the mechanical properties. 相似文献
18.
A series of NiMoW/P-Al 2O 3 catalysts with different Mo/W ratios (sample containing Mo only, Mo/W = 2: 1, Mo/W = 1: 1, Mo/W = 1: 2, and sample containing W only; P 2O 5 content of the support 2.0 wt %) were synthesized. The precursors of the active phase were the heteropoly acids H 3PMo 12O 40?nH 2O and H 3PW 12O 40?nH 2O, and also nickel citrate. The sulfide phase in the samples was studied by high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy; the catalytic activity of the samples in dibenzothiophene hydrodesulfurization and naphthalene hydrogenation was determined. For the dibenzothiophene hydrogenolysis in the presence of quinoline and naphthalene (content in the model mixture, wt %: dibenzothiophene 0.3, naphthalene 1.5, and quinoline 0.5), kHDS for different samples is in the range 17.6–42.5 h –1 at 275°C and 24.6–45.9 h –1 at 300°C. For the naphthalene hydrogenation, kHYD varies from 0.79 to 1.89 h –1 at 275°C and from 0.91 to 3.78 h –1 at 300°C. The sample based on molybdenum showed the highest activity in hydrogenation and hydrodesulfurization. 相似文献
19.
In the present work, nanofibrous composite polymer electrolytes consist of polyethylene oxide (PEO), ethylene carbonate (EC), propylene carbonate (PC), lithium perchlorate (LiClO 4), and titanium dioxide (TiO 2) were designed using response surface method (RSM) and synthesized via an electrospinning process. Morphological properties of the as‐prepared electrolytes were studied using SEM. FTIR spectroscopy was conducted to investigate the interaction between the components of the composites. The highest room temperature ionic conductivity of 0.085 mS.cm ?1 was obtained with incorporation of 0.175 wt. % TiO 2 filler into the plasticized nanofibrous electrolyte by EC. Moreover, the optimum structure was compared with a film polymeric electrolyte prepared using a film casting method. Despite more amorphous structure of the film electrolyte, the nanofibrous electrolyte showed superior ion conductivity possibly due to the highly porous structure of the nanofibrous membranes. Furthermore, the mechanical properties illustrated slight deterioration with incorporation of the TiO 2 nanoparticles into the electrospun electrolytes. This investigation indicated the great potential of the electrospun structures as all‐solid‐state polymeric electrolytes applicable in lithium ion batteries. 相似文献
20.
New cesium-conducting solid electrolytes based on cesium monoferrite in the Fe 2O 3-TiO 2-Cs 2O system are synthesized and studied. It is found that the introduction of titanium dioxide significantly reduces the electronic
component of conductivity, which prevails in pure CsFeO 2, and raises the ionic conductivity. The latter becomes predominant with increasing concentration of TiO 2. The effect of dimensional factor on the characteristics of electrolyte is shown. The optimal compositions studied have very
high cesium-cationic conductivity: it is above 10 −2 S cm −1 at 300°C. 相似文献
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