STRUCTURAL DESIGN OF HIGHLY ORIENTED LAYERED-MATERIAL FOR LITHIUM ION SECONDARY BATTERIES

锂离子二次电池高取向层状材料的结构设计

基本信息

批准号：
15360510
负责人：
YAO Takeshi
金额：
$ 9.92万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15360510/
关键词：
Lithium ion battery Layered compound Intercalated graphite X-ray diffraction Rietveld analysis Stacking manner Orientation state In-plane structure グラファイト X線回析ヒジテリシス

项目摘要

Lithium secondary batteries have been widely investigated due to their advantageous characteristics of light-weight, high energy density, high voltage and so on. For further progress such as reduction of cost and improvement of safety, development of materials of cathode and anode is crucial. For both cathode and anode, some of layered compounds are attractive in terms of specific capacity and cyclability. Graphite are commonly served as anode materials. Vanadium oxide gel and LiV_3O_8, which is one of so-called oxide bronze, employ layer structure and draw attentions as cathode materials. Their detail structure, however, is often difficult to be determined on the grounds that tendency of highly oriented state of their crystalline particles causes poor information of X-ray diffraction. As a result, structural control has been not enough so far. In this study, our purpose was to establish the structure of layered compounds suitable for high rate electrochemical reaction on the basis of detail structural analysis of them. That is ready to be applied to the electrode materials of lithium ion batteries. We prepared electrochemically a series of lithium intercalated graphite with various lithium content and analyzed structurally in the direction (c-direction) perpendicular to basal planes by X-ray diffraction using highly oriented sample. For the one-dimensional structural refinement, the highly oriented sample was adequate. Then we successfully determined the stacking manner of graphene layers using our originally developed one-dimensional Rietveld analysis system. We could discuss in-plane lithium distribution structure, as well as c-direction structure, depending on lithium intercalation level. Furthermore we found that the behavior of stage structure was hysteretic between in the process of electrochemical lithium insertion and extraction. The hysteresis was considered to be closely related to the structural variation of in-plane lithium arrangement.

锂二次电池由于具有重量轻、能量密度高、电压高等优点而受到广泛的研究。为了进一步降低成本和提高安全性，正极和负极材料的开发至关重要。对于正极和负极，一些层状化合物在比容量和循环性能方面都很有吸引力。石墨通常用作阳极材料。氧化钒凝胶和LiV_3O_8（所谓的氧化青铜之一）采用层状结构，作为阴极材料而受到关注。然而，它们的详细结构往往难以确定，因为它们的晶体颗粒的高度取向状态的倾向导致X射线衍射信息较差。因此，迄今为止，结构性控制还不够。在本研究中，我们的目的是在对层状化合物进行详细结构分析的基础上，建立适合高速电化学反应的层状化合物的结构。这已准备好应用于锂离子电池的电极材料。我们通过电化学方法制备了一系列具有不同锂含量的嵌锂石墨，并使用高度取向的样品通过 X 射线衍射在垂直于基面的方向（c 方向）进行结构分析。对于一维结构细化，高度定向的样本就足够了。然后，我们使用我们最初开发的一维Rietveld分析系统成功确定了石墨烯层的堆叠方式。我们可以根据锂嵌入水平讨论面内锂分布结构以及c方向结构。此外，我们发现在电化学锂嵌入和脱嵌过程中，阶段结构的行为是滞后的。滞后现象被认为与面内锂排列的结构变化密切相关。