全固态锂离子电池硫化物电解质的制备和性能研究

发布时间：2018-01-06 13:11

  本文关键词：全固态锂离子电池硫化物电解质的制备和性能研究　出处：《天津大学》2015年硕士论文　论文类型：学位论文

  更多相关文章： 全固态锂离子电池 硫化物固体电解质 离子电导率 化学稳定性 循环效率

【摘要】：锂离子电池作为动力电源已经广泛地应用于移动电子设备、混合型电子设备和分布式能源系统中。但是,由于传统的锂离子电池使用的是易燃的液体电解质,所以存在易燃、易泄漏、易腐蚀等安全隐患。随着高功率动力型锂离子电池的市场需求不断增长,人们对锂离子电池的能量密度的要求越来越高,导致锂离子电池的安全性问题越来越突出。全固态电池是一类以固体电解质取代传统液态电解质的新型高安全性锂离子电池,其电解质主要分为聚合物固态电解质和无机固态电解质。其中,由于具有更高的安全性,无机固体电解质得到了广泛的关注和快速的发展。无机固体电解质存在的主要缺点是离子电导率低,尚不能满足动力电池大电流放电的需要,因此提高离子电导率是无机固体电解质走向工业化应用的一个关键。目前Li_2S-P_2S_5体系硫化物固体电解质被认为是实现锂离子电池全固体化的最佳电解质材料之一,具有离子电导率高,电子电导率低,活化能小,机械强度高等优点,正成为国内外化学电源领域的一个研究热点。本文综述了全固态锂离子电池和硫化物固体电解质的最近研究进展,对Li_2S-P_2S_5基硫化物固体电解质进行了分类介绍,探讨了它们在实际应用中所存在的一些问题。采用机械研磨技术分别制备了二元Li_2S-P_2S_5、三元95(0.7Li_2S 0.3P_2S_5) 5Li_3PO_4和四元69Li_2S 26P_2S_5 3P_2O_5 2FeS硫化物玻璃态电解质,并组装成全固态LiCoO_2/Li锂离子电池。采用X射线衍射、差示扫描量热法、交流阻抗、循环伏安、扫描电子显微镜、透射电子显微镜恒电流充放电等测试手段对所制备的硫化物固体电解质和全固态电池性能进行了表征和测试。实验结果表明,所制备的三种硫化物电解质的在100℃时的电导率均在10-3 S cm-1以上,电化学窗口均能达到5V。电解质与金属Li负极相容性很好。通过溶胶-凝胶法对LiCoO_2表面进行包覆改性,分别包覆了Nb_2O_5、TiO_2、ZrO_2,包覆量在5 wt%左右。实验发现,包覆改性可以显著提高全固态锂离子电池的放电容量和放电平台电压。充放电测试结果显示,100℃时,全固态电池Li/SE/LiCoO_2的放电容量最高可达150 mAh g-1,循环50圈后的效率仍能达到95%以上。
[Abstract]:Lithium ion batteries have been widely used in mobile electronic devices, hybrid electronic devices and distributed energy systems as power supply. However, traditional lithium ion batteries use flammable liquid electrolytes. With the increasing market demand of high-power Li-ion batteries, the energy density of Li-ion batteries is more and more demanding. All solid state battery is a new type of high security lithium ion battery which replaces the traditional liquid electrolyte with solid electrolyte. Its electrolytes are mainly classified into polymer solid electrolyte and inorganic solid electrolyte. Inorganic solid electrolytes have received extensive attention and rapid development. The main shortcoming of inorganic solid electrolytes is the low ionic conductivity, which can not meet the needs of high current discharge of power batteries. Therefore, increasing ionic conductivity is a key to the industrial application of inorganic solid electrolytes. At present, sulphide solid electrolytes in Li_2S-P_2S_5 system are considered to be fully solid for lithium-ion batteries. One of the best electrolyte materials. It has the advantages of high ionic conductivity, low electronic conductivity, low activation energy and high mechanical strength. It is becoming a research hotspot in the field of chemical power supply at home and abroad. This paper reviews the recent research progress of all solid state lithium ion batteries and sulphide solid electrolytes. The classification of solid sulfide electrolytes based on Li_2S-P_2S_5 was introduced. Some problems existed in their practical application were discussed. Binary Li_2S-P_2S_5 was prepared by mechanical grinding technique. Three Yuan 95, 0.7Li2S, 0.3P2S5s _ _ _. Five Li3PO4 and four $69Li2S / 26P\\\'\\\?\\?\\\?\\\? All solid-state LiCoO_2/Li lithium-ion batteries were assembled by X-ray diffraction, differential scanning calorimetry, AC impedance, cyclic voltammetry and scanning electron microscope. The properties of sulfide-solid electrolyte and all-solid-state battery were characterized and tested by transmission electron microscope (TEM), constant current charge-discharge and so on. The conductivity of the three sulphide electrolytes was above 10-3 S cm-1 at 100 鈩，

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