共查询到20条相似文献,搜索用时 15 毫秒
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Mette Ø. Filsø Dr. Michael J. Turner Prof. Gerald V. Gibbs Prof. Stefan Adams Prof. Mark A. Spackman Prof. Bo B. Iversen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(46):15535-15544
The understanding of lithium‐ion migration through the bulk crystal structure is crucial in the search for novel battery materials with improved properties for lithium‐ion conduction. In this paper, procrystal calculations are introduced as a fast, intuitive way of mapping possible migration pathways, and the method is applied to a broad range of lithium‐containing materials, including the well‐known battery cathode materials LiCoO2, LiMn2O4, and LiFePO4. The outcome is compared with both experimental and theoretical studies, as well as the bond valence site energy approach, and the results show that the method is not only a strong, qualitative visualization tool, but also provides a quantitative measure of electron‐density thresholds for migration, which are correlated with theoretically obtained activation energies. In the future, the method may be used to guide experimental and theoretical research towards materials with potentially high ionic conductivity, reducing the time spent investigating nonpromising materials with advanced theoretical methods. 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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Zijian Zhang Miao Yang Dr. Xinjun Zhang Lichu Zhang Bo Liu Ping Zheng Wei Wang Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(10):2352-2361
Let's stick together : The gelation ability of a dendritic gelator has been enhanced by its complexation with a polyelectrolyte (see figure). This concept provides a route to construct novel functional or ordered materials by complexation of other low‐molecular‐mass functional species with polyelectrolytes.
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Aravindan V Gnanaraj J Madhavi S Liu HK 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(51):14326-14346
This paper presents an overview of the various types of lithium salts used to conduct Li(+) ions in electrolyte solutions for lithium rechargeable batteries. More emphasis is paid towards lithium salts and their ionic conductivity in conventional solutions, solid-electrolyte interface (SEI) formation towards carbonaceous anodes and the effect of anions on the aluminium current collector. The physicochemical and functional parameters relevant to electrochemical properties, that is, electrochemical stabilities, are also presented. The new types of lithium salts, such as the bis(oxalato)borate (LiBOB), oxalyldifluoroborate (LiODFB) and fluoroalkylphosphate (LiFAP), are described in detail with their appropriate synthesis procedures, possible decomposition mechanism for SEI formation and prospect of using them in future generation lithium-ion batteries. Finally, the state-of-the-art of the system is given and some interesting strategies for the future developments are illustrated. 相似文献
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作为颇有前途的锂离子电池负极材料,硅基材料的研究日益受到重视。硅基负极材料在充放电循环中体积变化过大导致的循环性能差、首次库仑效率低等始终是阻碍其商业化的主要问题。纳米化、合金化和碳包覆是有效的解决措施。本文详细论述了TiB2、TiN、TiC作为基质的硅-化合物复合物,Fe-Si、Cu-Si、Ni-Si体系的硅-金属复合物和硅-碳复合物的研究进展。在硅-碳复合物的研究上,综述了分别采用热解法、球磨法、球磨-热解法、化学聚合法合成,以聚吡咯、聚氯乙烯、聚丙烯腈、间苯二酚-甲醛、柠檬酸、环氧树脂等为碳源的研究进展,同时也综述了Si/碳纳米管复合电极材料的研究情况。 相似文献
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Kaimin Chen Yan Zhu Li Li Yan Lu Xuhong Guo 《Macromolecular rapid communications》2010,31(16):1440-1443
Spherical polyelectrolyte brushes consisting of a magnetite/polystyrene nanocomposite core and a poly(acrylic acid) brush shell were prepared by photo‐emulsion polymerization. They are narrowly dispersed, superparamagnetic and redispersible after aggregating by external magnetic field, as determined by transmission electron microscopy, dynamic light scattering, thermal gravimetric analysis and a vibrating sample magnetometer. Magnetic control is thus introduced into nano‐sized spherical polyelectrolyte brushes to achieve recovery and controllable delivery in applications. This approach opens up the way for cost‐effective applications of spherical polyelectrolyte brushes.
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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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Freeze‐Drying‐Assisted Synthesis of Hierarchically Porous Carbon/Germanium Hybrid for High‐Efficiency Lithium‐Ion Batteries 下载免费PDF全文
Herein, an approach is reported to prepare porous a carbon/Ge (C/Ge) hybrid. In this hybrid, Ge nanoparticles are closely embedded in a highly conductive and flexible carbon matrix. Such a hybrid features a high surface area (128.0 m2 g?1) and a hierarchical micropore–mesopore structure. When used as an anode material in lithium‐ion batteries (LIBs), the as‐prepared hybrid [C/Ge (60.37 %)] exhibits an improved lithium storage performance with regard to its capacity and rate capability compared to its counterparts. More specifically, it can maintain a specific capacity as high as 906 mAh g?1 at a high current density of 0.6 A g?1 after 50 cycles. The excellent lithium storage performance of the C/Ge (60.37 %) sample can be attributed to synergetic effects between the carbon matrix and Ge nanoparticles. The method we adopted is simple and effective, and can be extended to fabricate other nanomaterials. 相似文献
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We present the synthesis and the electrochemical characterization of polymeric electron transport materials, synthesized by polycondensation of substituted triazines and α,ω‐dihaloalkanes. They can be reversibly reduced with the least negative potential at −0.39 V, which is below the reduction potential of oxygen. In addition, the formation of polyelectrolyte multilayers is possible by the electrostatic self‐assembly method. This multilayer formation takes place in a very defined way up to thirty double layers.
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Dr. Lian Shen Prof. Zhaoxiang Wang Prof. Liquan Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(39):12559-12562
Prussian blues (or iron cyanides) and their analogues are attractive in both fundamental studies and industrial applications owing to their chemical and structural diversity. The large open space in their framework provides tunnels and space for the transport and storage of lithium ions. Two Prussian blues were synthesized by a co‐precipitation method. The nanosized Fe4[Fe(CN)6]3 and cubic FeFe(CN)6 deliver reversible capacities of 95 mAh g?1 and 138 mAh g?1, respectively. In comparison, FeFe(CN)6 shows cycling and rate performances superior to Fe4[Fe(CN)6]3. 相似文献