硅树脂和二氧化硅陶瓷浆料涂覆改性聚苯硫醚无纺布电池隔膜

发布时间：2018-04-28 00:26

本文选题：锂离子电池 + 隔膜　；参考：《武汉纺织大学》2017年硕士论文

【摘要】：目前,锂离子电池已经发展进入移动交通工具、能量储存系统等领域,这就要求电池具备高的能量密度和功率密度。然而,开发高性能电池就必须注重与之相关的两大挑战:安全隐患问题与电池性能受限的问题。隔膜作为锂离子电池的组成部分,起着隔离正极材料与负极材料,阻止电子通过的作用。隔膜虽然并不参与任何电池反应,但其结构和性能却对电池充放电性能及安全性能有着重要影响。因此,为了实现高能量密度锂离子电池的成功开发,必须发展高性能隔膜与之匹配。聚烯烃多孔隔膜比如PE或PP具有很多优点,并在商业化锂离子电池中占有绝对的主导地位。但是,聚烯烃隔膜的耐温性能有限,并具有相对较低的孔隙率以及较差的电解液浸润性,这会严重限制电池的安全性能及充放电性能。非织造布隔膜具有加工成本低,孔隙率高的特点,并且由于其选材范围比较广泛,可摆脱聚烯烃多孔膜选材单一的缺陷。于是,采用耐高温聚合物的非织造布制备高性能隔膜成为当今重要的发展方向。聚苯硫醚(PPS)具有很好的高温热稳定性、耐化学腐蚀性、阻燃、绝缘等优点。因此,用其制备的非织造布作为隔膜将在大容量锂离子动力电池中具有极大的应用潜力和产业化前景。基于此优势,本课题将以高性能的熔喷聚苯硫醚无纺布为基材,通过在其表面涂覆改性的办法,制备了聚苯硫醚基复合隔膜。并对隔膜的基本物理性能、电化学性能、电池性能进行了表征。具体研究内容如下:(1)在聚苯硫醚(PPS)无纺布表面物理涂覆乙烯基硅树脂(VSR),得到具有多孔结构的复合隔膜(VSR/PPS)。采用合适手段对复合隔膜的基本物理性能、电化学性能及电池性能进行了表征。研究发现,与商业化隔膜相比,复合隔膜具有良好的润湿性,这主要与复合隔膜高度发展的孔径结构及其组成材料极性有关。复合隔膜具有更高的放电比容量,这主要归功于复合隔膜优良的浸润性以及较高的孔隙渗透性,可以为隔膜提供较高的离子电导率与较低的界面阻抗。此外,我们还发现复合隔膜在高温下的尺寸稳定性要远远优于商业隔膜。(2)在聚苯硫醚(PPS)无纺布表面物理涂覆纳米SiO_2和聚偏二氟乙烯(PVDF),得到具有多孔结构的复合隔膜(SiO_2@PVDF/PPS)。采用合适手段对复合隔膜的基本物理性能、电化学性能及电池性能进行了表征。研究发现,与商业化隔膜相比,复合隔膜具有良好的润湿性,这主要与复合隔膜高度发展的孔径结构,涂覆了高比表面积的纳米SiO_2,具有亲液基团的PVDF以及组成材料极性有关,四者协同作用,增强了复合隔膜对电解液的吸收。复合隔膜具有更高的放电比容量,这主要归功于复合隔膜优良的浸润性以及较高的孔隙渗透性,可以为隔膜提供较高的离子电导率与较低的界面阻抗。此外,我们还发现复合隔膜在高温下的尺寸稳定性要远远优于商业隔膜,这主要是由于聚苯硫醚无纺布本身具有优异的热稳定性,同时在复合隔膜表面涂覆了耐热性能优良的纳米SiO_2导致,为高温环境条件下电池的工作提供了安全保障。
[Abstract]:At present, lithium ion batteries have developed into mobile vehicles, energy storage systems and other fields, which require a high energy density and power density of the battery. However, the development of high performance batteries must pay attention to the two major challenges related to it: the problem of hidden safety and the limited battery performance. The diaphragm is a lithium ion battery group. As a result, the separation of positive and negative materials and negative materials to prevent the passing of electrons. Although the diaphragm does not participate in any battery reactions, its structure and performance have an important impact on the charge discharge performance and safety performance of the battery. Therefore, high performance membranes must be developed in order to achieve the successful development of high energy density lithium ion batteries. Polyolefin porous membranes, such as PE or PP, have many advantages, and occupy an absolute dominant position in commercial lithium ion batteries. However, the temperature resistance of polyolefin membranes is limited, with relatively low porosity and poor electrolyte wettability, which will seriously restrict the safety and charge discharge performance of the battery. The cloth diaphragm has the characteristics of low processing cost and high porosity, and it can get rid of the single defect of material selection of polyolefin porous membrane because of its wide selection of material. Therefore, the preparation of high performance diaphragm with high temperature resistant polymer nonwovens has become an important direction of development. Polyphenylene sulfide (PPS) has good thermal stability in high temperature, Because of its advantages of chemical corrosion resistance, flame retardancy, insulation and so on. Therefore, using the nonwoven fabric prepared as a diaphragm, it will have great application potential and industrialization prospects in large capacity lithium ion power batteries. Based on this advantage, this topic will be based on high performance meltblown polyphenylene sulfide nonwoven fabric as a substrate, and will be prepared by coating modification on its surface. Polyphenylene sulfide based composite membranes were used to characterize the basic physical properties, electrochemical properties and battery properties of the diaphragm. The specific contents are as follows: (1) the porous structure of the composite diaphragm (VSR/PPS) was obtained on the surface of polyphenylene sulfide (PPS) nonwoven fabric with porous structure (VSR). The physical properties, electrochemical properties and battery performance were characterized. It was found that the composite diaphragm had good wettability compared with the commercial diaphragm, which was mainly related to the pore structure and its composition polarity, which was highly developed by the composite diaphragm. The composite diaphragm had higher discharge capacity, which is mainly due to the excellent performance of the composite diaphragm. The wettability and higher pore permeability can provide higher ionic conductivity and lower interfacial impedance for the diaphragm. In addition, we also found that the dimensional stability of the composite diaphragm at high temperature is far superior to that of the commercial diaphragm. (2) the nano SiO_2 and polyvinylidene fluoride (PVDF) coating on the surface of polyphenylene sulfide (PPS) nonwoven fabric are obtained. A composite diaphragm with porous structure (SiO_2@PVDF/PPS). The basic physical properties, electrochemical properties and battery performance of the composite diaphragm are characterized by appropriate means. It is found that the composite diaphragm has a good wettability compared with the commercial diaphragm, which is mainly with the pore structure developed highly with the composite diaphragm, coated with a high specific surface. The nanoscale SiO_2, with the PVDF of the hydrophilic group and the polarity of the material, enhanced the absorption of the electrolyte by the synergistic effect of the four groups. The composite diaphragm has a higher discharge ratio, which is mainly due to the excellent wettability and high porosity permeability of the composite diaphragm, which can provide a higher ionic electricity for the diaphragm. In addition, we also found that the dimensional stability of the composite diaphragm at high temperature is much better than that of the commercial diaphragm. This is mainly due to the excellent thermal stability of the polyphenylene sulfide nonwoven fabric itself. At the same time, the nano SiO_2 is coated on the surface of the composite diaphragm with excellent heat-resistant properties. The work of the pool provides security.

【学位授予单位】：武汉纺织大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TS176.5;TM912

【参考文献】