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JOINT STUDY ON DEVELOPMENT OF NEW INERCALATION ELECTRODES

新型嵌入电极开发联合研究

基本信息

批准号：
11695036
负责人：
KUMAGAI Naoki
金额：
$ 3.46万
依托单位：
IWATE UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

The present joint study aimed to develop new intercalation electrodes. The metal oxide electrodes have been synthesized by using soft-chemistry techniques such as an emulsion-drying method and hydrothermal method, and a dry preparation technique of r.f.-sputtering method. The carbon electrode has been synthesized by using liquid electrochemical reduction techniques. We have examined the crystal structure and the electrochemical characteristics of the prepared intercalation materials. Furthermore, we have performed the theoretical study on the lithium diffusion behavior in the crystal structure of the metal oxide. The main research results are as follows.1) LiAL_xMn_<2-x>O_4 spinel compound with high Al doping amount has been prepared by using the emulsion-drying method. The prepared mixed oxide showed excellent charge-discharge characteristics with high capacity of 120 mAh/g-oxide.2) New all-solid-state Li secondary cell consisting of LiMn_2O_4 cathode and V_2O_5 anode has been fabricated by using magnetron sputtering technique. This secondary cell showed excellent charge-discharge behavior at the cell voltages between 3.5 and 0.3 V with the capacity of 18 μA/cm^2.3) Carbon fine powders were obtained by the electrochemical reduction of liquid ternary system lithium-sodium-potassium carbonate at 450 ℃ using Ni electrodes. The carbon powders are found to consist of three different forms of carbon : graphite, amorphous carbon and carbon nanostructures. This third has an average diameter of 10 nm and is self-organized into long ropes.4) A new theoretical approach of the intercalation/deintercalation process of lithium cations into host materials is proposed taking into account of the dependence of the lithium diffusion coefficient on lithium concentration. This theoretical model was applied for the lithium diffusion in Nb_2O_5 crystal lattice.

目前的联合研究旨在开发新的嵌入电极。金属氧化物电极已经通过使用软化学技术如乳液干燥法和水热法以及r.f.溅射法采用液相电化学还原法制备了碳电极。我们研究了所制备的插层材料的晶体结构和电化学特性。此外，我们还对锂在金属氧化物晶体结构中的扩散行为进行了理论研究。主要研究结果如下：1）<2-x>采用乳液干燥法制备了高Al掺杂量的LiAl_xMn_ O_4尖晶石化合物。2）采用磁控溅射技术制备了以LiMn_2O_4为阴极、V_2O_5为阳极的新型全固态锂二次电池。该电池在3.5 ~ 0.3V的充放电电压范围内表现出良好的充放电性能，比容量为18 μA/cm^2。3）采用Ni电极在450 ℃下对锂-钠-钾三元体系碳酸盐进行电化学还原，得到了微细炭粉。发现碳粉由三种不同形式的碳组成：石墨、无定形碳和碳纳米结构。这第三个具有平均直径为10 nm，是自组织成长绳。4）一个新的理论方法的嵌入/脱嵌过程的锂阳离子到主体材料的锂扩散系数的锂浓度的依赖性考虑。将该理论模型应用于Nb_2O_5晶格中锂的扩散。