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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.

锂二次电池以其重量轻、能量密度高、电压高等优点得到了广泛的研究。为了进一步降低成本，提高安全性，阴极和阳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。石墨通常用作负极材料。氧化钒凝胶和LiV_3O_8是氧化物青铜的一种，它采用层状结构作为正极材料而备受关注。然而，它们的详细结构往往很难确定，因为它们的晶体粒子具有高度取向态的倾向，导致X射线衍射信息较差。因此，到目前为止，结构控制还不够。在本研究中，我们的目的是在详细分析层状化合物的结构的基础上，建立适合于高速电化学反应的层状化合物的结构。这已经准备好应用于锂离子电池的电极材料。我们用电化学方法制备了一系列不同锂含量的锂插层石墨，并用高取向样品进行了垂直于基面方向(c方向)的X射线衍射分析。对于一维结构的细化，高度取向的样品是足够的。然后，我们使用我们最初开发的一维Rietveld分析系统成功地确定了石墨烯层的堆积方式。我们可以讨论锂的平面分布结构，以及c方向的结构，这取决于锂的嵌入程度。此外，我们还发现，在电化学锂的插入和提取过程中，阶段结构的行为是滞后的。这种滞后现象被认为与锂平面排列的结构变化密切相关。