發(fā)布時間：2018-03-11 19:22

  本文選題：靜電紡絲　切入點：鋰離子電池隔膜　出處：《北京化工大學》2014年碩士論文　論文類型：學位論文

【摘要】：鋰離子電池產(chǎn)業(yè)近幾年成為具有廣闊前景的朝陽產(chǎn)業(yè)。越來越多鋰離子電池的主要材料被產(chǎn)業(yè)化制備,越來越多的鋰電課題被攻關。但是,近些年發(fā)生的鋰離子電池爆炸等不安全現(xiàn)象也引起了廣泛關注,安全問題急需解決。一般來說,很多鋰離子電池發(fā)生爆炸現(xiàn)象都是由于鋰離子電池內(nèi)部出現(xiàn)過熱現(xiàn)象,而過熱現(xiàn)象可以由很多條件引發(fā),例如,過充電、微短路、使用環(huán)境不當?shù)取Ｔ谶^高溫度下,鋰電隔膜起不到有效地隔離鋰電正負極的作用,從而引發(fā)爆炸�，F(xiàn)行商業(yè)化聚烯烴鋰離子電池隔膜強度高,化學穩(wěn)定性好,成本低,但是耐高溫性差,吸液率低。耐溫性差表現(xiàn)在當鋰離子電池發(fā)生過熱現(xiàn)象時易破裂,不能有效隔離電池正負極,引發(fā)爆炸。吸液率低不利于提高鋰電池的充放電容量的提高,限制了其大電流充放電性能。因此,對一種耐高溫、吸液能力強的鋰電隔膜的需求迫在眉睫。 電紡制備的無紡布纖維膜具備均勻的多孔結構,與鋰電隔膜的微孔結構類似。聚酰亞胺作為一種工程塑料,其具有高強高模、耐高低溫、耐輻射、耐溶劑和尺寸穩(wěn)定性等優(yōu)良性能,但是傳統(tǒng)熱固性聚酰亞胺的溶解性差,限制了其加工性。聚醚酰亞胺是一種熱塑性聚酰亞胺,一方面繼承了聚酰亞胺材料的優(yōu)異性能,而且其加工多樣性好,可溶液加工,可熔融加上。開且,聚醚酰亞胺體系目前已經(jīng)實現(xiàn)產(chǎn)業(yè)化生產(chǎn),原料來源廣泛且穩(wěn)定,有利于聚醚酰亞胺系列產(chǎn)品產(chǎn)業(yè)化的實現(xiàn)。 本文首先通過靜電紡絲法制備了無紡布聚酰亞胺纖維膜,然后采用熱致微交聯(lián)工藝,使無紡布纖維膜的相鄰纖維之間產(chǎn)生微熔融,從而在纖維膜中引入交聯(lián)點,實現(xiàn)纖維之間的熔接,通過改變工藝參數(shù),制備了具有不同交聯(lián)形貌的熱塑性聚酰亞胺纖維膜,機械強度比無紡布得到了大幅度提高,改善了過于開放的孔結構,提高了制品尺寸穩(wěn)定性,且孔隙率高,吸液率高,耐高溫性好。本文中,將交聯(lián)聚酰亞胺隔膜應用于鋰電隔膜,測試發(fā)現(xiàn)其在小電流和大電流充放電密度下均能起到隔離正負極的作用,隔膜充放電壽命長,電化學穩(wěn)定窗口高,且充放電多次后隔膜孔結構穩(wěn)定,具有很好的商業(yè)應用前景。
[Abstract]:In recent years, Li-ion battery industry has become a promising sunrise industry. More and more main materials of Li-ion battery have been industrialized, and more and more lithium electric problems have been solved. In recent years, unsafe phenomena such as lithium ion battery explosion have also aroused widespread concern, and safety problems need to be solved urgently. Generally speaking, many lithium ion batteries explosion phenomenon is due to the phenomenon of overheating inside the lithium ion battery. The phenomenon of overheating can be caused by many conditions, such as overcharging, micro-short circuit, improper use of the environment, etc. At too high temperature, the lithium diaphragm can not effectively isolate the positive and negative electrodes of lithium. The current commercial polyolefin lithium-ion battery has high strength, good chemical stability, low cost, but poor high temperature resistance and low liquid absorption. It can not effectively isolate the positive and negative electrodes of the battery and cause explosion. The low absorption rate is not conducive to increasing the charge and discharge capacity of the lithium battery and limits its high current charge-discharge performance. The demand of lithium electric separator with strong absorbency is urgent. The non-woven fiber membrane prepared by electrospinning has a uniform porous structure, similar to the micropore structure of the lithium electric diaphragm. As an engineering plastic, polyimide has high strength and high modulus, high temperature resistance and radiation resistance. Good properties such as solvent resistance and dimensional stability, but the poor solubility of traditional thermosetting polyimide limits its processability. Polyetherimide is a thermoplastic polyimide, which inherits the excellent properties of polyimide materials. In addition, the polyetherimide system has been produced in a wide and stable source, which is beneficial to the industrialization of polyetherimide products. In this paper, the non-woven polyimide fiber membrane was prepared by electrospinning method, and then the micro-crosslinking process was adopted to make the adjacent fibers of the non-woven fiber membrane micro-melt, so that the cross-linking point was introduced into the fiber membrane. The thermoplastic polyimide fiber membrane with different cross-linking morphology was prepared by changing the technological parameters. The mechanical strength of the film was greatly improved than that of the non-woven fabric, and the pore structure which was too open was improved. The product has high porosity, high liquid absorption and high temperature resistance. In this paper, the cross-linked polyimide membrane is applied to the lithium electric separator. It is found that it can isolate positive and negative electrodes at low current and high current charge / discharge densities. The diaphragm has long charge and discharge life, high electrochemical stability window, and stable pore structure after charging and discharging many times, so it has a good commercial application prospect.
【學位授予單位】：北京化工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TM912

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本文編號：1599556