共查询到20条相似文献,搜索用时 15 毫秒
1.
O. V. Yarmolenko K. G. Khatmullina L. M. Bogdanova N. I. Shuvalova E. A. Dzhavadyan A. A. Marinin V. I. Volkov 《Russian Journal of Electrochemistry》2014,50(4):336-344
Network copolymer electrolytes were synthesized from polyether (polyester) diacrylates with different structures and chain lengths of polyester diacrylate and polyethylene glycol diacrylate. The optimum matrix for ion transport in the electrolyte was formed from only one type of oligomer. The influence of TiO2 nanopowder additions (~60 nm) on the conductivity of the copolymer electrolyte was studied. The addition of 10 wt % TiO2 led to an increase in the conductivity by an order of magnitude at 30°C; the effective activation energy decreased by 20%. At elevated temperatures, the mobility of polymer chains increased and the contribution of TiO2 nanoparticles in ion transport was only half of the order of magnitude of the conductivity at 100°C. The increase in the conductivity of the polymer electrolyte after the addition of TiO2 was presumably caused by the formation of a more mobile state of the lithium ion near the nanoparticle surface, as shown by pulsed field gradient (PFG) 7Li NMR. 相似文献
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A. F. Shestakov A. V. Yudina G. Z. Tulibaeva K. G. Khatmullina T. V. Dorofeeva O. V. Yarmolenko 《Russian Journal of Electrochemistry》2014,50(11):1027-1035
To optimize the compositions of liquid organic electrolytes for lithium power sources, it is useful to have the dependence of the conductivity on the lithium salt concentration in a convenient analytical form. An empirical formula was suggested on the basis of the modified Kohlrausch equation for the concentration dependence of the conductivity of organic electrolytes in the vicinity of a maximum. The accuracy of this equation was checked on solutions of LiBF4 in propylene carbonate; LiClO4 in ethylene carbonate; and LiPF6 in ethylene carbonate/diethyl carbonate (1: 1), ethylene carbonate/ethylmethyl carbonate (1: 1), and ethylene carbonate/methyl acetate (1: 1) at different temperatures. The calculated data are in good agreement with experiment for all the systems. The new empirical formula allows the determination of the maximum conductivity of organic electrolytes based on a few points with good accuracy, which is very important in choosing the electrolyte salt concentration in practice. 相似文献
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K. G. Ishmukhametova O. V. Yarmolenko L. M. Bogdanova B. A. Rozenberg O. N. Efimov 《Russian Journal of Electrochemistry》2009,45(5):558-563
New solid polymer electrolytes are developed for a lithium power source used at the temperatures up to 100°C. Polyester diacrylate (PEDA) based on oligohydroxyethylacrylate and its block copolymers with polyethylene glycol were offered for polymer matrix formation. The salt used was LiClO4. The ionic conductivity of electrolytes was measured in the range of 20 to 100°C using the electrochemical impedance method. It is shown that the maximum conductivity in the whole temperature range is characteristic of the electrolyte based on the PEDA copolymer and polyethylene glycol condensation product (2.8 × 10?6 S cm?1 at 20°C, 1.8 × 10?4 S cm?1 at 95°C). 相似文献
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A kind of porous nanocomposite polymer membranes (NCPMs) based on poly(vinylidene difluoride-co-hexafluoropropylene) (P(VdF-HFP)) incorporated with different amounts of TiO2 nanoparticles from in situ hydrolysis of Ti(OC4H9)4 was prepared by a non-solvent induced phase separation (NIPS) technology. The SEM micrographs reveal that a porous structure exists in the NCPMs, which changes with the incorporated amount of TiO2. The NCPMs incorporated with 9.0 wt.% of mass fraction of TiO2 possess the highest porosity, 67.3%, and appear as flexile fracture with an elongation ratio, 74.4%. At this content, the ionic conductivity of the NCPE is up to 0.94 × 10−3 S cm−1 at room temperature and the activation energy for ions transport reaches the lowest, 18.71 kJ mol−1. It is of great potential application in lithium ion batteries. 相似文献
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Dong-Won Kim Jung-Ki Park Joon-Sung Bae Su-Il Pyun 《Journal of Polymer Science.Polymer Physics》1996,34(13):2127-2137
Blend-based polymer electrolytes composed of poly(ethylene oxide), poly(oligo[oxyethylene]oxysebacoyl), and lithium salts have been prepared. These polymer electrolytes have been investigated in terms of ionic conductivity, transport number, and interfacial characteristics of the lithium electrode in contact with the polymer electrolyte. The influences of the blend composition, the salt used, and its concentration on the electrochemical behavior were studied. © 1996 John Wiley & Sons, Inc. 相似文献
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Alexander S. Alekseev Ivan N. Domnin Artem B. Ivanov Nadezhda A. Tereschenko 《Mendeleev Communications》2018,28(4):409-411
The effect of prolonged UV irradiation and high temperature on a blue phase polymer film prepared by the Langmuir–Schaefer method based on 11-hydroxyundeca-6,8-diyn-1-yl N-(4-methoxyphenyl)carbamate was evaluated. The high stability of the polymer under extreme external influences was revealed. The transition of a monolayer to a bilayer with increasing surface pressure during the Langmuir layer formation was confirmed by atomic force microscopy. 相似文献
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Stephen G. Davies Ai M. Fletcher Paul M. Roberts James E. Thomson 《Tetrahedron: Asymmetry》2017,28(12):1842-1868
This review covers further applications of the conjugate addition of enantiomerically pure lithium amides as chiral ammonia equivalents in asymmetric synthesis and provides an update since our last review of this area, which was published in 2012. 相似文献
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A. A. Marinin K. G. Khatmullina V. I. Volkov O. V. Yarmolenko 《Russian Journal of Electrochemistry》2011,47(6):717-725
The processes of ionic conductivity are studied in a polymer gel electrolyte synthesized based on polyesterdiacrylate and
a low-molecular solvent ethylene carbonate. The self-diffusion coefficients of solvent molecules and Li+ cations are measured by the NMR with the pulsed magnetic field gradient. The Li+ self-diffusion coefficients increase with the increase in the solvent content and are independent of the diffusion time in
the interval from 10 to 1600 ms. The latter values imply the absence of limitations for the translational mobility of lithium
ions in the spatial range from 10−7 to 10−5 m. Based on the Nernst-Einstein equation, the ionic conductivities are calculated and compared with the experimental conductivities
measured by the impedance method. These values coincide for high contents of solvent; for low ethylene carbonate concentrations,
the calculated conductivities much exceed the experimental values. 相似文献
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K. S. Perera K. P. Vidanapathirana B. Jayamaha L. Wewagama M. A. K. L. Dissanayake G. K. R. Senadeera K. Vignarooban 《Journal of Solid State Electrochemistry》2017,21(12):3459-3465
In this work, the use of a polyethylene oxide-based nanocomposite polymer electrolyte (NCPE) in a redox capacitor with polypyrrole electrodes has been studied. To the best of our knowledge, not much work has been reported in the literature on redox capacitors fabricated using NCPEs. The composition of the polyethylene oxide (PEO)-based NCPE was fine tuned to obtain films with the highest ionic conductivity. They were mechanically stable to handle for any purpose without damaging the film. The optimized composition was {[(10PEO:NaClO4) molar ratio]: 75 wt.% propylene carbonate (PC)}: 5 wt.% TiO2. This electrolyte film showed an ambient temperature ionic conductivity of 5.42 × 10?3 S cm?1. It was employed in a redox capacitor with polypyrrole electrodes polymerized in the presence of sodium perchlorate in non-aqueous medium. Performance of the redox capacitors were observed using cycling voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge discharge test. It was possible to observe a satisfactory capacitive behavior in the range 58–83 F/g. Further, the redox capacitors had the ability to retain for continuous charge discharge processes. 相似文献
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Zheng Y Liu J Liao YP Ungar G Wright PV 《Dalton transactions (Cambridge, England : 2003)》2004,(19):3053-3060
Two Williamson procedures for the synthesis of the amphiphilic polymers poly[2,5,8,11,14-pentaoxapentadecamethylene(5-alkyloxy-1,3-phenylene)]I(abbrev. CmO5) are compared. Method X gives polyether-esters; method Y gives pure polyethers. In both, a dehydration reaction gives rise to CmO5-CmO1 copolymers. Two-phase systems of I with polyoxytetramethylene and polyoxytrimethylene copolymers (II) and LiBF(4) have been prepared with and without an interfacial stabiliser copolymer III. Highest and most stable conductivities (>5 x 10(-4) S cm(-1) at ambient) with low temperature dependence were observed with III, but I from method Y showed a tendency to phase separate at ambient. 相似文献
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Angesh Chandra Archana Chandra K. Thakur 《Russian Journal of General Chemistry》2013,83(12):2375-2379
Ion-conducting nanocomposite polymer electrolyte films based on poly(ethylene oxide)-NaPO3 3: 1 with up to 15 wt % of SiO2 have been prepared using recently developed hot-press technique instead of conventional solution cast method. With 7 wt % of SiO2, the film conductivity has been enhanced by an order of magnitude. The materials have been characterized by Fourier transform infrared spectrometry and thermogravimetric analysis. For the composition with the highest conductivity, the temperature dependences of ionic mobility, mobile ions concentration, ionic transference number, and ionic drift velocity have been determined. Dielectric constant and dielectric loss have been measured. The conductivity enhancement has been discussed on the basis of existing theories of dielectrics. 相似文献
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Ceramic fast-ion conductors have high ionic conductivities (>10?4 S cm?1) but are difficult to process and have poor chemo/mechanical properties at the electrode/electrolyte interfaces. In contrast, polymer electrolytes are pliable and easy to process but suffer from low room-temperature ionic conductivities (≈10?6-10?7 S cm?1). Combining these two elements to form a composite polymer electrolyte is a promising way to enable all-solid-state lithium-metal batteries. The choice of ceramic filler and polymer can be tailored to provide synergistic benefits that overcome the practical shortcomings of the two components. Herein, the fundamentals of Li+ conduction through the various phases and interfaces in these materials are discussed as well as the important parameters, beyond the initial choice of polymer and ceramic filler materials that must be considered while designing composite polymer electrolytes. Emphasis is placed on the particle filler engineering and practical fabrication methods as routes toward enhancing the properties of these composites. 相似文献
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Review on gel polymer electrolytes for lithium batteries 总被引:1,自引:0,他引:1
A. Manuel Stephan 《European Polymer Journal》2006,42(1):21-42
This paper reviews the state-of-art of polymer electrolytes in view of their electrochemical and physical properties for the applications in lithium batteries. This review mainly encompasses on five polymer hosts namely poly(ethylene oxide) (PEO), poly(acrylonitrile) (PAN), poly(methyl methacrylate) (PMMA), poly(vinylidene fluoride) (PVdF) and poly(vinylidene fluoride-hexafluoro propylene) (PVdF-HFP) as electrolytes. Also the ionic conductivity, morphology, porosity and cycling behavior of PVdF-HFP membranes prepared by phase inversion technique with different non-solvents have been presented. The cycling behavior of LiMn2O4/polymer electrolyte (PE)/Li cells is also described. 相似文献