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Search for Novel Carbon Based Nanonetwork Materials and their Properties

寻找新型碳基纳米网络材料及其性能

基本信息

批准号：
11165218
负责人：
IWASA Yoshihiro
金额：
$ 28.1万
依托单位：
Japan Advanced Institute of Science and Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas (A)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

(1) Intercalation processes of carbon nanotubes with alkali metalsOne of the possible application of single walled carbon nanotubes (SWNT) is the anode of the Li ion batteries. We have uncovered the intercalation processes by means of the spectroscopic methods, such as Raman, infrared, and XPS. First, alkali metals are inserted into interstitial sites surrounded by three tubes, followed by an insertion into the smaller site between two tubes, causing a serious expansion of the intertube distances. Until this state, A3C80, the concentration of alkali metals increases continuously, but displays a discontinuous jump to A9C80, above which the A concentration shows a continuous increase again.(2) Molecular orientations and magnetic structures in fullerene antiferromagnetsWe have systematically synthesized (NH_3)A_3C_<60>, by intercalating neutral ammonia molecules into A_3C_<60> superconductors, and found that all the monoammoniated compounds are antiferromagnetic insulators. (NH_3)A_3C_<60 … More > adopts an orthorhombic unit cell derived by a slight deformation of the fcc cell of A_3C60, and because of this deformation, the electron is localized on the C_<60> moiety. Furthermore, the magnetic structure and molecular orientations have been determined by NMR, and neutron scattering experiments, respectively. The correlation between these displays a nice analogy to the relation between the orbital and spin orderings in transition metal oxides magnets, which is known as Kanamori-Goodenough rule.(3) Novel dimer structure in rare earth metal doped fulleridesIntercalation of fullerenes with rare earth metals has been investigated. Among these, we succeeded in synthesizing single phase Sm_3C_<70>, and in determining the crystal structure in a electron density level, by means of MEM/Rietveld analysis. It was found that two neighboring C_<70> moieties are connected by the Sm ion, forming a new type of dimer structure. This dimer structure is considerably stable, because the structure is maintained at least up to 850K, in contrast to the bond breaking in the conventional fullerene polymers showing a bond breaking below 600K.(4) Dielectric properties of La@C_<82> thin filmsWe have fabricated thin films of the metallofullerene La@C_<82>, and measured dielectric constants as a function of temperature. The dielectric constant at room temperature is about 40, approximately one order larger than that of C_<60> (4.4). The considerably large dielectric constant is presumably due to the rotation of the molecules with a large dielectric moment. Such dipolar activity of La@C_<82> might suggest that the molecular rotation states could be controlled by the external electic field. Less

(1)碳纳米管与碱金属的插层过程单壁碳纳米管（SWNT）的一个可能的应用是锂离子电池的阳极。利用拉曼光谱、红外光谱和XPS等光谱方法研究了插层过程。首先，碱金属被插入到由三个管包围的间隙部位，然后插入到两个管之间的较小部位，导致管间距离的严重扩展。直到该状态A3 C80，碱金属的浓度持续增加，但显示出到A9 C80的不连续跳跃，在A9 C80以上，A浓度再次显示出持续增加。(2)富勒烯反铁磁材料的分子取向和磁性结构我们<60>通过将中性氨分子插入到A_3C_2<60>超导体中，系统地合成了（NH_3）A_3C_2，发现所有的单氨化化合物都是反铁磁绝缘体。(NH_3）A_3C_<60 ...更多信息 >采用了由A_3C_（60）的面心立方晶胞变形而成的斜方晶系晶胞，由于这种变形，电子定域在C_（<60>60）部分。此外，磁结构和分子取向已确定由NMR和中子散射实验，分别。这些之间的相关性显示了过渡金属氧化物磁体中轨道和自旋有序之间的关系，这被称为Kanamori-Goodenough规则。(3)稀土金属掺杂富勒烯的新型二聚体结构研究了稀土金属对富勒烯的插层作用。其中，我们成功地合成了单相Sm_3C_2<70>，并通过MEM/Rietveld分析确定了电子密度水平上的晶体结构。发现两个相邻的C_2<70>部分通过Sm离子连接，形成一种新型的二聚体结构。这种二聚体结构是相当稳定的，因为该结构保持至少高达850 K，与常规富勒烯聚合物中的键断裂形成对比，该键断裂显示低于600 K的键断裂。(4)La@C_2薄膜的介电性质<82>我们制备了金属富勒烯La@C_2薄膜，<82>并测量了介电常数随温度的变化。室温下的介电常数约为40，比C_（4.4）的介电常数大一个数量级<60>。相当大的介电常数可能是由于具有大介电矩的分子的旋转。La@C_3的这种偶极活性<82>可能表明分子的转动状态可以由外电场控制。少