【作者】 张联忠；

【导师】 唐致远； 徐强； 大石繁；

【作者基本信息】 天津大学 ， 应用化学， 2006， 硕士

【摘要】 锂离子电池以其高能量、安全可靠、寿命长、无污染等优点,成为目前最具有发展前途的高能二次电池。随着锂离子电池的进一步发展的需要,人们越来越多的要求可充电锂离子电池电极材料具有更高的比容量和更好的安全性,寻找和开发能够取代现有碳材料的新型负极材料成为当今研究的热点。本论文针对非碳类负极材料主要进行了两方面的初步探索研究。论文采用圆柱型电池对Si/C复合负极材料和石墨化碳负极材料的循环和倍率性能进行了研究,并对实际应用中存在的问题以及失效原因进行了分析。Si/C负极电池200次循环后容量维持率仅为69.5%,并且放电平台低于石墨化碳负极材料。造成其容量衰减快的主要原因为电极体积膨胀导致的电极活性物质脱落,电接触性能变差,极化增大容量损失,SEI膜被破坏,进而电解液不断的分解,界面膜增大,电阻增加,以及材料本身结构造成的插入的锂无法全部脱出,是造成容量损失是的最主要原因。论文对尖晶石结构的锂钛复合氧化物Li₄Ti₅O₁₂负极材料的固相合成法及材料的性能进行了研究。对不同锂源、不同培烧温度、培烧时间、有无分散剂等条件进行了实验研究,优化了最佳合成材料条件。制备的Li₄Ti₅O₁₂负极样品在1.55V（vs Li/Li+）附近有平稳的放电平台,充电电压平台略高于放电电压平台,电池首次放电容量为146mAh/g,具有稳定的循环性能,该材料结构稳定,是一种高安全长寿命的锂离子电池负极材料。更多还原

【Abstract】 Lithium-ion batteries are most promising high power secondary batteries due to its advantages of higher energy density, more safety, longer lifetimes and no pollution. In order to satisfy the demand of Lithium-ion batteries development, it is necessary for people to find electrode material with high capacity and better safe. And it is a research topic to find new type anode material to replace traditional carbon materials. The paper is mainly focused on the preliminary study on two aspects of anode material.The cycle and rate performance of the cyclindrical cell with Si/C and graphite anode were studied in this paper. Also the problem occurred in application as well as the failure mechanism was analyzed. Capacity retainment was keeping 69.5% of the initial capacity after 200 cycles. And discharge platform was a bit lower than that of graphite anode. The reason of fast capacity fading mainly are the electrode active material felling off due to electrode volume swelling leading to worse electric contact that result in greater polarization and less capacity; SEI film was destroyed and followed gradually electrolyte decomposition which result in thicker interface film and greater impedance. And the main reason for the capacity loss is the Li⁺ ion can not be fully deserted due to internal structure of the material.The solid phase synthesize method of Li₄Ti₅O₁₂ and its performance was studied in this paper. The condition of different lithium resources, different calcining temperature and time, and with or without dispersing agent and so on were studied. The best synthesis experiment condition was optimized. There is steady discharging platform around 1.55V（vs Li/Li⁺） of Li₄Ti₅O₁₂ samples where charging platform was a bit higher than the discharging platform. The first specific discharging capacity is 146mAh/g. It exhibit steady cycle performance. The material is a higher safe and longer lifetimes lithium ion anode material.更多还原