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Novel composite anode materials for lithium secondary battery

新型锂二次电池复合负极材料

基本信息

批准号：
18350106
负责人：
TAKEDA Yasuo
金额：
$ 10.37万
依托单位：
Mie University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

Lithium ion batteries are principle and promising power sources for a wide variety of electronics. Electrode material is a key for developing further lithium ion batteries, which are likely to require good reliability and high energy density. However, graphitic carbon that is currently used as negative electrode material in the commercial Li-ion batteries appears to be unsatisfied due to low theoretic capacity of 372 mAh g^-1 and poor thermal stability under lithiated state. Therefore, there is even-increasing research in the feasibility of the replacement of graphitic anodes. By this motivation, a series of novel negative electrode materials that demonstrate extremely high capacities and different Li reactive mechanisms have been proposed in this group.1.Li-alloy based compositesThe volume effects of silicon upon Li insertion and extraction can be effectively suppressed by designing a composite microstructure containing that ultrafine silicon are uniformly dispersed in a ductile condu … More cting carbonaceous matrix with electron/ion conductivity. By this way, several types of Si-based composites have been developed by means of pyrolyis process in accompany with high-energy mechanical milling step. The pyrolyzed carbon can mostly function as an elastic network with electron/ion conductivity that permits the silicon in the matrix to operate while maintaining .electrode integrity. The Si-based composites have large capacity of ca. 1000 mAh g^-1 and good cycling performance, as well as acceptable first cycle efficiency. We expect that further optimization of these Si-composite based anodes might lead to practical lithium-ion batteries with high energy density.2.Lithium transition metal nitrides based composite electrodeWe have developed a series of lithium mixed transition metal(co-doped)nitrides with high electrochemical capacity and good cyclability. For producing these compounds, a combination of a solid-state reaction under an appropriate temperature and a high-energy mechanical milling step was involved. Research reveals that the granular structure of the nitrides shows obvious effects upon the electrochemical behavior. The lithiated compounds can be used in several ways to form new composite electrodes which demonstrate high insertion capacity, 100 % first cycle efficiency and excellent capacity retention ability. Therefore, they are promising anode candidates for further Li-ion batteries. Less

锂离子电池是一种原理和有前途的电源，适用于各种各样的电子产品。电极材料是进一步发展锂离子电池的关键，这可能需要良好的可靠性和高能量密度。然而，目前作为商用锂离子电池负极材料的石墨碳，由于其372 mAh g^-1的理论容量较低，且在锂化状态下的热稳定性较差，似乎不能令人满意。因此，对石墨阳极替代的可行性的研究也越来越多。在这一动机下，本小组提出了一系列具有极高容量和不同锂反应机制的新型负极材料。通过设计一种复合材料微观结构，使超细硅均匀地分散在具有电子/离子导电性的碳质基体中，可以有效地抑制硅对Li插入和提取的体积效应。在此基础上，采用高能机械铣削工艺制备了几种类型的硅基复合材料。热解后的碳主要可以作为具有电子/离子导电性的弹性网络，允许基体中的硅在保持运行的同时运行。电极的完整性。硅基复合材料具有约1000 mAh g^-1的大容量和良好的循环性能，以及可接受的第一次循环效率。我们期望进一步优化这些硅复合材料基阳极可能会导致实用的高能量密度锂离子电池。基于过渡金属氮化锂的复合电极我们开发了一系列具有高电化学容量和良好循环性能的混合过渡金属（共掺杂）氮化锂。为了生产这些化合物，需要在适当温度下进行固态反应和高能机械铣削步骤的结合。研究表明，氮化物的颗粒结构对电化学行为有明显的影响。该锂化化合物可用于多种方式形成新的复合电极，具有高插入容量，100%的第一次循环效率和优异的容量保持能力。因此，它们是未来锂离子电池极有前途的阳极候选者。少