新型耐高电压隔膜和丙烯酸酯聚合物电解质的制备及性能测试

发布时间：2018-05-02 18:20

本文选题：高电压锂离子电池 + 隔膜　；参考：《青岛大学》2017年硕士论文

【摘要】：锂离子电池正在逐步应用在移动智能设备、电动汽车、航空航天、航海、以及众多大型工业中。发展高电压、高能量的锂离子电池体系迫在眉睫,隔膜和电解质作为锂离子电池中重要组成部分之一,在高电压锂离子电池发展中起着十分关键的作用。因此,研发新型宽电化学窗口、高离子电导率和安全性能的耐高电压隔膜和电解质是高电压锂离子电池研究的重点。本文选用可再生的,具有良好的热稳定性的海藻酸盐无纺布膜作为5 V高电压锂离子电池隔膜。通过测试发现:海藻酸盐隔膜最大拉伸强度为37 MPa,具有良好的机械性能,在150 oC以下热稳定性好,尺寸不发生收缩。30 oC时的离子电导率为1.4×10-3 S/cm。用海藻酸盐隔膜组装的5 V LiNi0.5Mn1.5O4(LNMO)/Li电池在55oC下200圈的循环保持率为79.6%,高于同等条件下的PP2500的半电池(69.3%)。除此之外,海藻酸盐隔膜组装的LiFePO4/Li半电池在150 oC下能够正常充放电。因此,海藻酸盐隔膜能够应用在5 V高电压锂离子电池隔膜领域。以三乙二醇二甲基丙烯酸酯(TEGDMA)为单体,碳酸丙烯酯(PC)为增塑剂,锂盐选用二氟草酸硼酸锂(LiDFOB)配制前聚体溶液,引发剂选用偶氮二异丁腈(AIBN),通过原位聚合方法制备三乙二醇二甲基丙烯酸酯聚合物(CTE)凝胶态聚合物电解质。合成的CTE凝胶聚合物电解质在25 oC下的离子电导率为1.64×10-4 S cm-1。电化学窗口为2.5 V-4.75 V,离子迁移数为0.62。该电解质组装的LCoO2/Li半电池在25oC下具有良好的倍率性能和循环性能。这归功于电解质较高的离子电导率和离子迁移数以及较好的界面稳定性。由此可见CTE凝胶聚合物电解质能够适用于高电压LiCoO2锂离子电池电解质领域。本文提出的海藻酸盐隔膜和CTE凝胶态聚合物电解质具有良好的电化学稳定性,应用在高电压锂离子电池中表现出较好的循环和倍率性能,十分适用于高电压锂离子电池领域,对高电压锂离子电池的发展具有重要意义。
[Abstract]:Lithium-ion batteries are being used in mobile smart devices, electric vehicles, aerospace, navigation, and many large industries. It is urgent to develop high voltage and high energy lithium ion battery system. As one of the important components of lithium ion battery, diaphragm and electrolyte play a very important role in the development of high voltage lithium ion battery. Therefore, the research and development of new high voltage barrier and electrolyte with wide electrochemical window, high ionic conductivity and safety performance are the focus of research on high voltage lithium ion batteries. In this paper, a regenerative alginate nonwoven film with good thermal stability is used as a 5 V high voltage lithium ion battery diaphragm. The results show that the maximum tensile strength of alginate separator is 37 MPA, and it has good mechanical properties, and the ionic conductivity is 1.4 脳 10 ~ (-3) S-1 路cm ~ (-1) under 150oC, and the ionic conductivity is 1.4 脳 10 ~ (-3) S-1 路cm ~ (-1) when the size does not shrink. The cycle retention rate of the 5 V LiNi0.5Mn1.5O4(LNMO)/Li cell assembled with alginate diaphragm at 200 cycles under 55oC was 79.6, which was higher than that of the half-cell of PP2500 under the same conditions. In addition, the alginate membrane assembled LiFePO4/Li semi-cells can charge and discharge normally at 150oC. Therefore, alginate separator can be used in the field of 5 V high voltage lithium ion battery diaphragm. The prepolymer solution was prepared by using triethylene glycol dimethacrylate (TEGDMA) as monomer and propylene carbonate (PC) as plasticizer, and lithium salt was prepared with lithium difluorooxalate borate (LiDFOB). The gel polymer electrolyte of triethylene glycol dimethacrylate polymer (CTE) was prepared by in-situ polymerization with azodiisobutyronitrile (AIBN) as initiator. The ionic conductivity of the synthesized CTE gel polymer electrolyte is 1.64 脳 10 ~ (-4) S / cm ~ (-1) at 25oC. The electrochemical window is 2.5 V-4.75 V and the ion mobility is 0.62V. The LCoO2/Li half-cell assembled by the electrolyte has good performance of rate and cycle under 25oC. This is due to the high ionic conductivity, ionic mobility and better interfacial stability of the electrolyte. Therefore, CTE gel polymer electrolyte can be used in high voltage LiCoO2 lithium-ion battery electrolyte field. The alginate separator and CTE gel polymer electrolyte presented in this paper have good electrochemical stability, and have been applied to high voltage lithium ion batteries with good cycling and rate performance, and are very suitable for high voltage lithium ion batteries. It is of great significance to the development of high voltage lithium ion battery.
【学位授予单位】：青岛大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O646;TM912

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