生物多糖纤维基锂离子电池隔膜的制备及其性能研究

发布时间：2018-04-11 12:24

本文选题：海藻酸钙纤维 + 纤维素纤维　；参考：《青岛大学》2017年硕士论文

【摘要】：锂离子电池由于其能量密度高、工作电压高而又环保等突出的优点在电子类产品中被广泛应用。电池隔膜是锂离子电池结构中的重要组成之一,在提高锂离子电池的安全性能以及降低成本上,隔膜发挥着重要的作用。本论文中以生物多糖纤维(海藻酸钙纤维和纤维素纤维)为主要原料制备了高安全性和高电池容量的锂离子电池隔膜。(1)通过抄纸技术制备了生物多糖纤维基锂离子电池复合隔膜,对隔膜的透气性、吸液率等物理性质的表征,结果表明制备的复合隔膜与电解液具有较好的浸润效果。通过对隔膜进行极限氧指数测试(LOI)、差热分析法(DTA)以及在不同温度下的收缩形貌的表征,隔膜在较高的温度下不会出现热收缩的现象,对提高隔膜的安全性有突破性的进步。复合隔膜组成的电池后其离子电导率在1.22×10-3 S/cm左右,相对于Celgard 2500(PP)隔膜的离子电导率(0.17×10-3 S/cm)较高,并且复合隔膜的内阻相对较低,电化学窗口测试发现复合隔膜的电化学窗口在4.5 V左右。复合隔膜组成的磷酸铁锂半电池,具有较高的放电容量、较好的长循环和倍率循环性能,有利于获得大容量的锂离子电池。(2)通过纳米无机材料(Al_2O_3和SiO_2)涂覆这种方式对70%海藻酸钙纤维含量复合隔膜(70%AlgF)进行改性,发现改性后的隔膜其孔隙率降低、强度提高(未涂覆的隔膜的强度的4倍),并且其热稳定性更好.(3)通过前面的探究发现,在复合隔膜中海藻酸钙纤维含量越高,隔膜的电化学性能越好。通过添加可溶性海藻酸盐(海藻酸钠和海藻酸镁)作为粘结剂来制备海藻酸钙纤维隔膜,结果发现隔膜孔径变小,纤维之间的结合力增强,隔膜的强度有了显著的提高。通过测试电化学窗口测试发现,隔膜电化学窗口为5 V,并且其组成电池后电池容量较高。
[Abstract]:Lithium ion batteries are widely used in electronic products because of their high energy density, high working voltage and environmental protection.Battery diaphragm is one of the most important components in lithium-ion battery structure. It plays an important role in improving the safety performance and reducing the cost of lithium-ion battery.In this paper, the lithium-ion battery separator with high safety and high battery capacity was prepared from biopolysaccharide fiber (calcium alginate fiber and cellulose fiber). The lithium-ion separation based on biopolysaccharide fiber was prepared by paper-making technique.Subbattery composite diaphragm,The physical properties of the membrane, such as gas permeability and liquid absorption rate, were characterized. The results showed that the composite membrane and electrolyte had better wetting effect.By means of limiting oxygen index (Oi) test, differential thermal analysis (DTA) and the characterization of shrinkage morphology at different temperatures, the thermal shrinkage of the diaphragm is not observed at higher temperature, which is a breakthrough in improving the safety of the diaphragm.The ionic conductivity of the composite membrane was about 1.22 脳 10 ~ (-3) S/cm, which was higher than that of the Celgard 2500p / m membrane (0.17 脳 10 ~ (-3) S / cm), and the internal resistance of the composite membrane was relatively low.Electrochemical window test showed that the electrochemical window of composite diaphragm was about 4.5 V.The composite membrane of lithium iron phosphate battery has high discharge capacity, good performance of long cycle and rate cycle.It was found that the modified membrane with 70% calcium alginate fiber content was modified by using nano-inorganic materials such as Als _ 2O _ 3 and Sio _ 2), and the porosity of the modified membrane was lower than that of the modified membrane.The results show that the higher the content of calcium alginate fiber in the composite membrane, the better the electrochemical performance of the membrane. The higher the strength is (4 times of the strength of the uncoated membrane, and the better the thermal stability of the membrane is, the higher the content of calcium alginate fiber in the composite membrane is, the higher the content of calcium alginate fiber is).Calcium alginate fiber separator was prepared by adding soluble alginate (sodium alginate and magnesium alginate) as binder. The results showed that the pore size of the membrane became smaller and the adhesion between the fibers increased, and the strength of the membrane increased significantly.The electrochemical window test shows that the diaphragm electrochemical window is 5 V, and the battery capacity is high after the battery is made up.
【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】：TM912

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