共查询到20条相似文献,搜索用时 15 毫秒
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Masahiro Murayama Ryoji Kanno Michihiko IrieShinya Ito Takayuki HataNoriyuki Sonoyama Yoji Kawamoto 《Journal of solid state chemistry》2002,168(1):140-148
The new lithium ionic conductors, thio-LISICON (LIthium SuperIonic CONductor), were found in the ternary Li2S-SiS2-Al2S3 and Li2S-SiS2-P2S5 systems. Their structures of new materials, Li4+xSi1−xAlxS4 and Li4−xSi1−xPxS4 were determined by X-ray Rietveld analysis, and the electric and electrochemical properties were studied by electronic conductivity, ac conductivity and cyclic voltammogram measurements. The structure of the host material, Li4SiS4 is related to the γ-Li3PO4-type structure, and when the Li+ interstitials or Li+ vacancies were created by the partial substitutions of Al3+ or P5+ for Si4+, large increases in conductivity occur. The solid solution member x=0.6 in Li4−xSi1−xPxS4 showed high conductivity of 6.4×10-4 S cm−1 at 27°C with negligible electronic conductivity. The new solid solution, Li4−xSi1−xPxS4, also has high electrochemical stability up to ∼5 V vs Li at room temperature. All-solid-state lithium cells were investigated using the Li3.4Si0.4P0.6S4 electrolyte, LiCoO2 cathode and In anode. 相似文献
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Michelle Prevot Christophe Déjugnat Helmuth M?hwald Gleb B Sukhorukov 《Chemphyschem》2006,7(12):2497-2502
Layer-by-layer assembled polyelectrolyte microcapsules are of great interest because they can possibly be used as microcontainers and they show interesting stimuli-responsive properties, which have been recently investigated. Here, we exploit capsules which are made temperature-sensitive by encapsulating poly(N-isopropylacrylamide) (PNIPAM). PNIPAM has a cloud point in water at about 32 degrees C, above which it collapses and is insoluble in water. Further this temperature responsiveness can be tuned by addition of various ions at various concentrations. Here, we present the encapsulation of PNIPAM inside polyelectrolyte microcapsules, and describe the dependence of the lower critical solution temperature (LCST) on the nature and the amount of different salts added. With this information, we demonstrate the ability to tune and finely control the collapse of encapsulated PNIPAM. In this light, this system could be used as a microsensor or drug- delivery system. 相似文献
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Ryan L. Weber Yuesheng Ye Steven M. Banik Yossef A. Elabd Michael A. Hickner Mahesh K. Mahanthappa 《Journal of Polymer Science.Polymer Physics》2011,49(18):1287-1296
Polymerized ionic liquids (PILs) are a platform for fundamental studies of structure‐property relationships in single ion conductors, with potential applications in energy storage and conversion. The synthesis, thermal properties, and ionic conductivities of homologous, narrow dispersity styrenic PILs are described. Hydrophilic poly(4‐vinylbenzyl alkylimidazolium chloride) (PVBn(alkyl)ImCl) homopolymers with constant average degrees of polymerization were synthesized by post‐synthetic functionalization of a poly(4‐vinylbenzyl chloride) (Mn = 15.9 kg/mol, Mw/Mn = 1.34) master batch with N‐alkylimidazoles (alkyl = ? CH3 (Me), ? C4H9 (Bu), and ? C6H13 (Hex)). The chloride counterions of PVBnHexImCl were exhaustively metathesized with BF, PF, and bis(trifluoromethanesulfonyl)imide (TFSI?) to yield a series of hydrophobic PILs. Thermogravimetric analyses indicate that PVBn(alkyl)ImCl homopolymers are unstable above 220 °C, whereas the hydrophobic PILs remain stable up to 290 °C. The glass transition temperatures (Tg) decrease with both increasing alkyl side‐chain length and increasing counterion size, exemplified by Tg = 9 °C for PVBnHexImTFSI. Hydrophilic PILs exhibit high ionic conductivities (as high as ~0.10 S cm?1) that depend on the relative humidity, water uptake, and the PIL side chain length. The hydrophobic PILs exhibit lower conductivities (up to ~5 × 10?4 S cm?1) that depend predominantly on the polymer Tg, however, counterion size and symmetry also contribute. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1287–1296, 2011 相似文献
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Prof. Makoto Moriya Daiki Kato Prof. Wataru Sakamoto Prof. Toshinobu Yogo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(40):13554-13560
The molecular crystals [Li{N(SO2CF3)2}{C6H4(OCH3)2}2] and [Li{N(SO2CF3)2}{C6F2H2(OCH3)2}2] with solid‐state lithium ion conductivity have been synthesized by the addition of two equivalents of 1,2‐dimethoxybenzene or 1,2‐difluoro‐4,5‐dimethoxybenzene to Li{N(SO2CF3)2}, respectively. Single‐crystal X‐ray diffraction analysis revealed the formation of ionic conduction paths with an ordered arrangement of lithium ions in these crystal structures, afforded by the self‐ assembled stacking of molecular‐based channels consisting of N(SO2CF3)2 anion and 1,2‐dimethoxybenzene frameworks as a result of intermolecular aromatic and hydrogen interactions. These compounds show selective lithium ion conductivity as the anions behave as a component unit of the conduction paths. The relationship between the crystal structure and ionic conductivity of the molecular crystals provides a clue to the development of novel solid electrolytes based on molecular crystals showing fast and selective lithium ion conduction. 相似文献
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聚阴离子型锂离子电池正极材料研究进展 总被引:18,自引:0,他引:18
综述了各种聚阴离子型锂离子电池正极材料的研究现状,重点对各种材料的结构和性能的关系,尤其是聚阴离子在正极材料中的作用,以及改善材料电导率的各种方法及其机理进行了总结和探讨. 相似文献
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Dirk Apitz Ralph Peter Bertram Nils Benter Peter Sommer-Larsen Per Michael Johansen Karsten Buse 《Chemphyschem》2006,7(2):468-474
The conductivity properties of electro-optic, photoaddressable, dense bis-azo chromophore polymer films are investigated by using samples corona poled at various temperatures. A dielectric spectrometer is applied to measure the frequency dependence of the conductivity at different temperatures before and after heating the material to above the glass transition temperature. The results show that the orientation of the chromophores changes the charge-carrier mobility. Ionic conductivity dominates in a more disordered configuration of the material, while the competing process of hole hopping takes over as a transition to a liquid-crystalline phase occurs when the material is heated to much higher than the glass transition temperature. Such microcrystallization strongly enhances the conductivity. 相似文献
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以乙酸锰和钛酸四丁酯为原料,柠檬酸为络合剂,采用溶胶-凝胶法制备钛酸锰(MnTiO3)粉体,而后将其粉体高温氨气氮化,可得到MnO/TiN复合材料. 使用X射线衍射(XRD)、X射线能量色散谱(EDS)和场发射扫描电子显微镜(FESEM)表征材料的物相结构与组分、观察其形貌. 采用循环伏安、恒流充放电和电化学阻抗方法测试电极电化学性能. 结果表明,MnO/TiN电极在100 mA?g-1和1 A?g-1倍率放电下,比容量分别为394 mAh?g-1和146 mAh?g-1,均高于单纯MnO电极比容量和倍率性能,这归因于复合材料中的TiN提供了导电网络,并有效地抑制了电极在充放电过程中的体积膨胀效应. 相似文献
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近几十年,二次锂电池作为重要的储能装置得到迅猛发展,而开发高性能的锂电池电极材料一直是电化学能源领域的研究热点之一。与传统无机正极材料相比,聚合物正极材料具有比容量高、柔软性好、廉价易得、环境友好、加工方便、可设计性强等诸多优点。本文综述了导电聚合物、共轭羰基聚合物以及含硫聚合物正极材料的结构特点、电极反应机理、电化学性能和近五年来的重大研究进展,总结了这三类聚合物电极材料的优缺点,并重点介绍了含硫聚合物电极材料中存在的问题及改进手段,最后提出了综合这三类聚合物优点的含硫共轭导电聚合物将会是该领域的研究方向。 相似文献
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Dr. Sebastian Huber Prof. Dr. Arno Pfitzner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(39):13683-13688
Li17Sb13S28 was synthesized by solid‐state reaction of stoichiometric amounts of anhydrous Li2S and Sb2S3. The crystal structure of Li17Sb13S28 was determined from dark‐red single crystals at room temperature. The title compound crystallizes in the monoclinic space group C2/m (no. 12) with a=12.765(2) Å, b=11.6195(8) Å, c=9.2564(9) Å, β=119.665(6)°, V=1193.0(2) Å3, and Z=4 (data at 20 °C, lattice constants from powder diffraction). The crystal structure contains one cation site with a mixed occupation by Li and Sb, and one with an antimony split position. Antimony and sulfur form slightly distorted tetragonal bipyramidal [SbS5E] units (E=free electron pair). Six of these units are arranged around a vacancy in the anion substructure. The lone electron pairs E of the antimony(III) cations are arranged around these vacancies. Thus, a variant of the rock salt structure type with ordered vacancies in the anionic substructure results. Impedance spectroscopic measurements of Li17Sb13S28 show a specific conductivity of 2.9×10?9 Ω?1 cm?1 at 323 K and of 7.9×10?6 Ω?1 cm?1 at 563 K, the corresponding activation energy is EA=0.4 eV below 403 K and EA=0.6 eV above. Raman spectra are dominated by the Sb?S stretching modes of the [SbS5] units at 315 and 341 cm?1 at room temperature. Differential thermal analysis (DTA) measurements of Li17Sb13S28 indicate peritectic melting at 854 K. 相似文献
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Dr. Zhiping Song Dr. Yumin Qian Dr. Mikhail L. Gordin Dr. Duihai Tang Dr. Terrence Xu Prof. Minoru Otani Prof. Hui Zhan Prof. Haoshen Zhou Prof. Donghai Wang 《Angewandte Chemie (International ed. in English)》2015,54(47):13947-13951
In spite of recent progress, there is still a lack of reliable organic electrodes for Li storage with high comprehensive performance, especially in terms of long‐term cycling stability. Herein, we report an ideal polymer electrode based on anthraquinone, namely, polyanthraquinone (PAQ), or specifically, poly(1,4‐anthraquinone) (P14AQ) and poly(1,5‐anthraquinone) (P15AQ). As a lithium‐storage cathode, P14AQ showed exceptional performance, including reversible capacity almost equal to the theoretical value (260 mA h g?1; >257 mA h g?1 for AQ), a very small voltage gap between the charge and discharge curves (2.18–2.14=0.04 V), stable cycling performance (99.4 % capacity retention after 1000 cycles), and fast‐discharge/charge ability (release of 69 % of the low‐rate capacity or 64 % of the energy in just 2 min). Exploration of the structure–performance relationship between P14AQ and related materials also provided us with deeper understanding for the design of organic electrodes. 相似文献