【作者】 张鼎；

【导师】 顾大明；

【作者基本信息】 哈尔滨工业大学 ， 无机化学， 2007， 硕士

【摘要】 锂离子二次电池作为目前广泛应用的一种高性能二次电池,正在朝着能量密度更高、使用更安全的全固态聚合物电池(聚合物正极+固体聚合物电解质+金属锂负极)方向发展。普通的无机纳米粒子掺杂制备的聚合物-锂盐-纳米粒子型复合聚合物电解质(简称复合聚合物电解质)较原始的聚合物-锂盐型复合聚合物电解质表现出许多优点,但是仍然不能够满足实用要求。作为一个新兴的研究领域,聚合物-锂盐-层状硅酸盐型复合聚合物电解质的研究表现出特殊意义。本项研究使用溶液浇铸法分别引入改性蒙脱土(MMT)和皂石制备PEO-LiClO4-层状硅酸盐型复合聚合物电解质,首先研究了硅酸盐含量、插层时间、热处理等制备工艺对复合聚合物电解质离子电导率的影响,确定优化的制备工艺;进而利用FTIR,SEM和XRD等手段对制备的产品进行表征,观测材料离子电导率增强时的表面形貌变化和微观结构变化。实验利用优化的工艺制得的PEO-LiClO4-蒙脱土型和PEO-LiClO4-皂石型复合聚合物电解质20℃离子电导率分别达到6.5×10-5S/cm和1.4×10-4S/cm,优于一般的无机纳米粒子掺杂的复合聚合物电解质。XRD测试发现蒙脱土和LiClO4的引入都降低了PEO的结晶度。皂石的引入起到同样的效果,而引入皂石时LiClO4的存在不但进一步降低了材料的结晶度,也导致了PEO峰特征峰位置的明显移动。FTIR测试发现蒙脱土和皂石片层与片层表面物质都有较强的相互作用。SEM观测结果表明,LiClO4引入到PEO中时,PEO表面细化,而蒙脱土的加入使得表面更加平滑,有利于获得低阻的聚合物界面。此外,本项研究依据经验公式对本课题的得到的电导率数据作拟合,发现所研究的体系在离子传导方面虽然呈现了较大的离子跃迁性特征,但是聚合物体系粘度对离子电导也有影响。更多还原

【Abstract】 As a widely applied high-powered chargeable battery, lithium ion secondary batteries are developed into pure solid state polymer battery (polymer cathode, solid polymer electrolyte and lithium anode) with higher energy density and better safety performance. Composite solid polymer electrolyte(in short, Composite polymer electrolyte), described as polymer-lithium salt-nano particle, prepared by adding common nano particles, acts better than the original polymer-lithium salt composite polymer electrolyte, but it still can not meet the request of application. As a novel field of composite polymer electrolyte, those ones on composite polymer electrolyte prepared by adding layered silicate have showed a special future.PEO-LiClO4-layered silicate composite polymer electrolytes are prepared on the introduction of MMT and saponite in this research by solution-casting method. Factors of the concentration of silicate、the intercalating time and the time for heat treatment and so on are checked to confirm their effect on the conductivity of composite polymer electrolyte to obtain optimal techniques. Furthermore, FTIR, SEM and XRD are used to test the product with the aim to get the details of changes of surface and structure when the ionic conductivity is enhanced.Prepared PEO-LiClO4-MMT and PEO-LiClO4-saponite composite polymer electrolyte by optimal techniques present ionic conductivity of 6.5×10-5S/cm and 7.3×10-5S/cm at 20℃respectively, which are better than composite polymer electrolyte prepared by adding common nano particles. XRD tests indicate that the introduction of MMT and LiClO4 both decrease the crystallization of PEO. The addition of saponite has the similar effect, but the introduction of LiClO4 at the same time does not only lower the crystallization of PEO, but also move the characteristic absorption of PEO. FTIR tests show that the layers of MMT and saponite both interact with other components on the surface area. SEM tests present an idea that the introduction of LiClO4 is resulted in lubricity of the surface of PEO film, while the addition of MMT smooth the surface, which would help gain a low-impedance polymer interface. Besides, the experimental data on conductivity are fitted by experiential formula, indicating that although the composite polymer electrolyte owns some ion-conducting feature with hopping mechanism, the viscosity of electrolyte affects its conductivity at the same time.更多还原