氧化铝陶瓷涂层对锂离子电池性能影响的研究

发布时间：2018-01-10 22:06

本文关键词：氧化铝陶瓷涂层对锂离子电池性能影响的研究　出处：《中南大学》2014年硕士论文　论文类型：学位论文

【摘要】：摘要：安全性能是制约锂离子电池大型化发展的关键,影响锂离子电池安全性能因素有很多。陶瓷涂层具有良好的电解液浸润性和耐高温性能,是提高电池电化学性能和安全性能的一种途径。本文从锂离子电池电极的角度出发,研究成本低并与电池兼容性好的陶瓷涂层,旨在提高锂离子电池的电化学性能和安全性能。本文在查阅文献的基础上,优选了工业化原料纳米氧化铝为陶瓷原料,研究了纳米氧化铝的物化性能和粘结剂的种类比例对陶瓷涂层的影响,陶瓷涂层与石墨的相容性以及对全电池电化学性能和安全性能的影响。采用了循环伏安法(CV)、交流阻抗(EIS)、恒流充放电和扫描电子显微镜(SEM)、X射线衍射(XRD)等测试表征手段,研究了陶瓷涂层理化性能及其对电池性能的影响,获得的主要结果如下： 1)纳米氧化铝颗粒的分散性能直接影响陶瓷涂层的均匀性。采用粒径小、分散均匀的氧化铝能够有效防止浆料团聚,油系陶瓷涂层与水系石墨负极相容性最好。高温干燥后的陶瓷涂层具有纳米级微孔,有利于电解液浸润和吸收。 2)陶瓷涂层中氧化铝颗粒与粘结剂比例对电池性能有重要影响。比较氧化铝颗粒与聚合物粘结剂比例分别为9：1(AG-T1)和8：2(AG-T2), AG-T1的首次充放电效率为83.3%,与普通石墨负极的82.9%相当,而AG-T2的首次效率为80.4%。扣式电池循环结果表明,T1能够提高电池循环性能,T2降低电池循环性能。扣式电池的交流阻抗和循环伏安图谱表明,T1涂层与电池负极的相容性好。 3)吸液和保液率测试表明,陶瓷涂层有利于电解液吸收和保存。负极涂覆陶瓷涂层后,循环500次容量保持率在88.6%,相比普通电池容量保持率为85.3%。陶瓷涂层也在一定程度上提高了电池的倍率性能和低温性能。在针刺、短路、挤压、重物冲击、热箱安全实验中,陶瓷涂层电池均未出现热失控,而普通电池在针刺、重物冲击、热箱试验中均起火爆炸,说明陶瓷涂层能够提高电池的安全性能。陶瓷涂层电池在循环300次后电池保持较好的安全性能,但没有通过500次循环后的安全试验。负极极片电镜表明,500次循环后陶瓷涂层出现剥离,这是造成安全性能下降的主要原因。
[Abstract]:Abstract: safety performance is the key to the development of lithium-ion batteries. There are many factors affecting the safety performance of lithium-ion batteries. Ceramic coatings have good electrolyte wettability and high temperature resistance. It is a way to improve the electrochemical performance and safety performance of the battery. From the point of view of the lithium ion battery electrode, the ceramic coating with low cost and good compatibility with the battery is studied in this paper. The aim of this paper is to improve the electrochemical and safety performance of lithium ion batteries. On the basis of literature review, the industrial raw material nano-alumina was selected as ceramic material, and the effects of physical and chemical properties of nano-alumina and the proportion of binder on ceramic coating were studied. The compatibility of the ceramic coating with graphite and its effect on the electrochemical and safety properties of the whole battery were investigated by cyclic voltammetry (CV) and AC impedance spectroscopy (EIS). The physical and chemical properties of ceramic coatings and their effects on battery performance were studied by means of constant current charge-discharge and scanning electron microscopy (SEM). The main results were as follows:. 1) the dispersion properties of nano-alumina particles directly affect the uniformity of ceramic coatings. Using alumina with small particle size and uniform dispersion can effectively prevent slurry agglomeration. The oil system ceramic coating has the best compatibility with the aqueous graphite negative electrode, and the ceramic coating after high temperature drying has nanometer micropores, which is favorable for electrolyte infiltration and absorption. 2) the ratio of alumina particle to binder in ceramic coating has an important effect on the performance of battery. The ratio of alumina particle to polymer binder is 9: 1 / AG-T1) and 8: 2 / 2 AG-T2 respectively. . The first charge and discharge efficiency of AG-T1 is 83.3, which is equivalent to that of normal graphite anode 82.9%, while the first efficiency of AG-T2 is 80.4. T1 can improve the cycle performance of the battery and T2 can reduce the cycle performance of the battery. The AC impedance and cyclic voltammetry of the buttoned battery show that the compatibility of the T1-coating with the negative electrode of the battery is good. 3) the liquid absorption and retention rate test showed that the ceramic coating was beneficial to the absorption and preservation of electrolyte. After coating the ceramic coating on the negative electrode, the capacity retention rate of 88.6% cycles was obtained. Compared with the ordinary battery capacity retention rate is 85.3. Ceramic coating also improves the battery performance and low temperature performance to a certain extent. In needle piercing, short circuit, extrusion, heavy impact, hot box safety experiments. Ceramic coated batteries did not appear heat out of control, but ordinary batteries in acupuncture, heavy impact, hot box test are all on fire and explosion. The results show that ceramic coating can improve the safety performance of the battery, and the ceramic coating battery keeps a good safety performance after 300 cycles. The negative electrode sheet electron microscope showed that the ceramic coating was peeled off after 500 cycles, which was the main reason for the deterioration of safety performance.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM912

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