發(fā)布時(shí)間：2018-04-28 00:26

  本文選題：鋰離子電池 + 隔膜　； 參考：《武漢紡織大學(xué)》2017年碩士論文

【摘要】：目前,鋰離子電池已經(jīng)發(fā)展進(jìn)入移動(dòng)交通工具、能量?jī)?chǔ)存系統(tǒng)等領(lǐng)域,這就要求電池具備高的能量密度和功率密度。然而,開(kāi)發(fā)高性能電池就必須注重與之相關(guān)的兩大挑戰(zhàn):安全隱患問(wèn)題與電池性能受限的問(wèn)題。隔膜作為鋰離子電池的組成部分,起著隔離正極材料與負(fù)極材料,阻止電子通過(guò)的作用。隔膜雖然并不參與任何電池反應(yīng),但其結(jié)構(gòu)和性能卻對(duì)電池充放電性能及安全性能有著重要影響。因此,為了實(shí)現(xiàn)高能量密度鋰離子電池的成功開(kāi)發(fā),必須發(fā)展高性能隔膜與之匹配。聚烯烴多孔隔膜比如PE或PP具有很多優(yōu)點(diǎn),并在商業(yè)化鋰離子電池中占有絕對(duì)的主導(dǎo)地位。但是,聚烯烴隔膜的耐溫性能有限,并具有相對(duì)較低的孔隙率以及較差的電解液浸潤(rùn)性,這會(huì)嚴(yán)重限制電池的安全性能及充放電性能。非織造布隔膜具有加工成本低,孔隙率高的特點(diǎn),并且由于其選材范圍比較廣泛,可擺脫聚烯烴多孔膜選材單一的缺陷。于是,采用耐高溫聚合物的非織造布制備高性能隔膜成為當(dāng)今重要的發(fā)展方向。聚苯硫醚(PPS)具有很好的高溫?zé)岱�(wěn)定性、耐化學(xué)腐蝕性、阻燃、絕緣等優(yōu)點(diǎn)。因此,用其制備的非織造布作為隔膜將在大容量鋰離子動(dòng)力電池中具有極大的應(yīng)用潛力和產(chǎn)業(yè)化前景�；诖藘�(yōu)勢(shì),本課題將以高性能的熔噴聚苯硫醚無(wú)紡布為基材,通過(guò)在其表面涂覆改性的辦法,制備了聚苯硫醚基復(fù)合隔膜。并對(duì)隔膜的基本物理性能、電化學(xué)性能、電池性能進(jìn)行了表征。具體研究?jī)?nèi)容如下:(1)在聚苯硫醚(PPS)無(wú)紡布表面物理涂覆乙烯基硅樹(shù)脂(VSR),得到具有多孔結(jié)構(gòu)的復(fù)合隔膜(VSR/PPS)。采用合適手段對(duì)復(fù)合隔膜的基本物理性能、電化學(xué)性能及電池性能進(jìn)行了表征。研究發(fā)現(xiàn),與商業(yè)化隔膜相比,復(fù)合隔膜具有良好的潤(rùn)濕性,這主要與復(fù)合隔膜高度發(fā)展的孔徑結(jié)構(gòu)及其組成材料極性有關(guān)。復(fù)合隔膜具有更高的放電比容量,這主要?dú)w功于復(fù)合隔膜優(yōu)良的浸潤(rùn)性以及較高的孔隙滲透性,可以為隔膜提供較高的離子電導(dǎo)率與較低的界面阻抗。此外,我們還發(fā)現(xiàn)復(fù)合隔膜在高溫下的尺寸穩(wěn)定性要遠(yuǎn)遠(yuǎn)優(yōu)于商業(yè)隔膜。(2)在聚苯硫醚(PPS)無(wú)紡布表面物理涂覆納米SiO_2和聚偏二氟乙烯(PVDF),得到具有多孔結(jié)構(gòu)的復(fù)合隔膜(SiO_2@PVDF/PPS)。采用合適手段對(duì)復(fù)合隔膜的基本物理性能、電化學(xué)性能及電池性能進(jìn)行了表征。研究發(fā)現(xiàn),與商業(yè)化隔膜相比,復(fù)合隔膜具有良好的潤(rùn)濕性,這主要與復(fù)合隔膜高度發(fā)展的孔徑結(jié)構(gòu),涂覆了高比表面積的納米SiO_2,具有親液基團(tuán)的PVDF以及組成材料極性有關(guān),四者協(xié)同作用,增強(qiáng)了復(fù)合隔膜對(duì)電解液的吸收。復(fù)合隔膜具有更高的放電比容量,這主要?dú)w功于復(fù)合隔膜優(yōu)良的浸潤(rùn)性以及較高的孔隙滲透性,可以為隔膜提供較高的離子電導(dǎo)率與較低的界面阻抗。此外,我們還發(fā)現(xiàn)復(fù)合隔膜在高溫下的尺寸穩(wěn)定性要遠(yuǎn)遠(yuǎn)優(yōu)于商業(yè)隔膜,這主要是由于聚苯硫醚無(wú)紡布本身具有優(yōu)異的熱穩(wěn)定性,同時(shí)在復(fù)合隔膜表面涂覆了耐熱性能優(yōu)良的納米SiO_2導(dǎo)致,為高溫環(huán)境條件下電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.

【學(xué)位授予單位】：武漢紡織大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TS176.5;TM912

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本文編號(hào)：1812985