权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Structural and Electronic State Changes of Spinel Oxides During Lithium Insertion and Extraction

锂嵌入和脱嵌过程中尖晶石氧化物的结构和电子态变化

基本信息

批准号：
06650745
负责人：
KANAMURA Kiyoshi
金额：
$ 1.22万
依托单位：
KYOYO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

An insertion and extraction of lithium into/from spinel LiMn_2O_4 were analyzed by X-ray diffraction and electron spin resonance methods. From these analyzes, it can be seen that LiMn_2O_4 become unstable with decreasing lithium content. In order to prevent such a behavior, a new spinel compound was developed in this study. In general, spinel compounds sometimes have a cation ordering in their structure. This cation ordering provides a stabilization to a crystal structure. Therefore, the unstableness of LiMn_2O_4 caused by a lithium extraction may be overcome by such a stabilization energy from the cation ordering effect. In this study, we prepared Li_<4/3>Mn_<5/3>O_4 which has a cation ordering at 16d sites. In this compound, Li and Mn ions occupied 16d sites in a regular manner, that was confirmed by X-ray diffraction method. The structural and electronic state changes of this Mn compound were analyzed by X-ray diffraction and electrochemical methods. The X-ray diffraction patterns at various lithium contents could not be distinguished, indicating that the structural change of this super structure spinel is infinitesimal. This structural behavior is like an ideal one for lithium insertion and extraction materials. The electrochemical potential change was also investigated under a galvanostatic condition. The potential did not change during the lithium insertion and extraction. Usually, the electrode potential changes gradually with changing lithium content. So, the electrochemical behavior of this super structure spinel is extremely interesting. The same behaviors were also observed for super structure spinel of Ti (Li_<4/3>Ti_<5/3>O_4) . Thus, the super structure provides a very unique characteristics which has never been reported anywhere.

用X射线衍射和电子自旋共振（ESR）方法研究了锂在尖晶石LiMn_2O_4中的嵌入和脱嵌过程。从这些分析可以看出，随着锂含量的降低，LiMn_2O_4变得不稳定。为了防止这种行为，本研究开发了一种新的尖晶石化合物。一般来说，尖晶石化合物有时在其结构中具有阳离子排序。这种阳离子有序化为晶体结构提供了稳定性。因此，这种由阳离子有序效应产生的稳定化能可以克服由锂提取引起的LiMn_2O_4的不稳定性。本研究制备了Li_（4/3）Mn_（5/3）O_4，它具有16 d位的阳离子有序性。在该化合物中，Li和Mn离子以规则的方式占据16 d位，这由X射线衍射方法证实。用X射线衍射和电化学方法分析了锰化合物的结构和电子态的变化。不同锂含量下的X射线衍射图谱不能区分，表明这种超结构尖晶石的结构变化是极其微小的。这种结构行为类似于锂嵌入和提取材料的理想结构行为。在恒电流条件下，还研究了电化学电位的变化。在锂插入和拔出过程中，电位没有变化。通常，电极电位随着锂含量的变化而逐渐变化。因此，这种超结构尖晶石的电化学行为非常有趣。超结构尖晶石Ti（Li_<4/3>Ti_<5/3>O_4）也观察到了同样的行为。因此，超级结构提供了一个非常独特的特性，这是从来没有报道过的。