Novel composite anode materials for lithium secondary battery

锂离子电池是各种电子产品的主要和有前途的电源。电极材料是进一步开发锂离子电池的关键，这可能需要良好的可靠性和高能量密度。然而，目前在商用锂离子电池中用作负极材料的石墨碳似乎并不令人满意，这是由于其理论容量较低（372 mAh g^-1）和锂化状态下热稳定性较差。因此，对石墨阳极替代的可行性的研究越来越多。基于这一动机，本课题组提出了一系列具有极高容量和不同锂反应机理的新型负极材料：1.锂合金基复合材料通过设计一种包含超细硅均匀分散在韧性导电体中的复合结构，可以有效抑制硅对锂嵌入和脱出的体积效应。 ...更多信息 具有电子/离子传导性的碳质基质。通过这种方法，已经开发了几种类型的硅基复合材料的热解过程中，伴随着高能机械球磨步骤。热解的碳可以主要用作具有电子/离子传导性的弹性网络，其允许基质中的硅操作，同时保持电极完整性。硅基复合材料具有很大的钙容量。1000 mAh g^-1和良好的循环性能，以及可接受的首次循环效率。我们期望这些硅基复合阳极的进一步优化可能会导致具有高能量密度的实用锂离子电池。2.锂过渡金属氮化物基复合电极我们开发了一系列锂混合过渡金属（共掺杂）氮化物，具有高的电化学容量和良好的循环性能。为了生产这些化合物，涉及在适当温度下的固态反应和高能机械研磨步骤的组合。研究表明，氮化物的颗粒结构对电化学行为有明显的影响。锂化化合物可以以几种方式用于形成新的复合电极，其表现出高插入容量、100%的首次循环效率和优异的容量保持能力。因此，它们是用于进一步的锂离子电池的有希望的阳极候选者。少

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