【作者】 李雪莉；

【导师】 江志裕；

【作者基本信息】 复旦大学 ， 物理化学， 2005， 博士

【摘要】 日益严峻的全球化能源危机和环境污染已经成为当今人类社会可持续发展过程中面临的两大挑战,开发新一代高性能、长寿命、无污染、价格低廉的绿色化学电源已成为电池工业发展的必然趋势。 聚合物锂离子电池不仅具有比液态锂离子电池更高的比能量,而且由于电池中不存在游离电解质,改善了液态锂离子电池可能存在的不安全以及漏液等问题,并使电池的形状尺寸设计更加灵活。 其中全固态聚合物锂离子电池很有发展前景。以聚氧化乙烯（PEO）为基底的固体电解质是目前最受人们重视的聚合物电解质之一。但是它的室温导电率较低,尚不实用。因此,提高其室温电导率是当前应该解决的首要问题。 金属锂具有最负的电极电位和最高的金属比容量,是最有前途的负极材料。但由于充电时产生枝晶和表层粉末化,存在的安全问题限制了其在商品化电池中的应用,这一问题如果得到解决,将促使锂二次电池早日走向市场。 随着新型正极材料的发展,未来的锂离子或锂二次电池必将具有更高的电压和更高的比能量密度,这对电池集流体材料的电化学稳定性也提出了更高的要求。因此对锂离子电池常用集流体的腐蚀性能进行研究,提高正极集流体材料的耐腐蚀性能具有重要的实际意义。 为此,本论文主要针对上述问题进行了研究,并取得以下成果: 1.本论文首次采用功能型含锂的介孔材料LiAlSBA、Li-FER与PEO/LiClO₄制成全固态复合聚合物电解质。与空白样品相比,所获得的复合聚合物电解质室温电导率提高了约三个数量级,在30℃～80℃温度范围内PEO复合聚合物电解质的电导率均得到提高。其他电化学性能也得到明显改善,包括:代表有效离子迁移电荷比例的阳离子转移数（t₊）,盐的扩散系数（D_s）和阴、阳离子的离子扩散系数（D₊,D_-）都得到提高。电解质的稳定性以及锂金属和复合聚合物电解质之间的协和性也得到改善。 通过XRD、TGA、DSC、以及IR等测试手段研究分析了含锂介孔材料提高聚合物电解质电导率的内在机制。首次在填料/PEO/LiClO₄聚合物电解质体系中引入偏光显微（PLM）技术。结果表明,介孔材料的加入,不仅起到阻碍聚合物链段有序排列的作用,而且聚合物电解质中的晶粒得到细化,非晶区增加。更多还原

【Abstract】 More and more serious global power and environmental crisis have become the two main problems which the human being has to face during the process of continuous development for the society. It is an inevitable tendency to develop a new kind of green chemical power source with good performance, long cycling life, no pollution and low price.Polymer lithium ion battery not only has the higher specific energy than liquid lithium ion battery, but also can resolve the problems of leakage and unsafety in liquid electrolyte lithium ion battery, and the shape of polymer lithium ion battery can be designed flexibly as well.Solid polymer lithium battery is one of the most promising kind of batteries. Poly(ethylene oxide)(PEO) is regarded as one of the most excellent polymer matrix. But its conductivity at room temperature is very low. Therefore the principal duty is to enhance the ambient ionic conductivity of PEO electrolyte.Lithium metal is the most promising anode material because of its most negative normal electrode potential and the highest specific energy. However, the dendritic lithium and lithium powderization will be produced during the charge process, therefore the potential safety problem confines the commercial application for lithium anode. Resolution of this problem will help the secondary lithium battery come into the market.With the development of novel cathode materials, the future lithium battery or lithium ion battery will possess much higher specific energy density and higher potential, which requires the higher electrochemical stability for the current collectors. Therefore, it has practical meaning to increase the corrosion resistance of the current collectors.In this work, much effort has been devoted to investigating the problems above, and the results as follows:1. Two kinds of mesoporous materials containing lithium, LiAlSBA and Li-FER, are used as fillers to PE0/LiC104 polymer electrolytes. Compared with barePE0/LiC104 sample, the ionic conductivities at 30"C for composite electrolytes with LiAlSBA and Li-FER are both enhanced three orders, and exhibit good performance in temperature range of 30°C ~ 80°C. In addition, other electrochemical performances are also increased greatly, including the cation transference number (t+) representing the effective ion transference number, the diffusion coefficient (Ds) and the cation and anion diffusion coefficients (D+, D.). The electrochemical windows and the compatibility between lithium metal anode and the composite polymer electrolytes are improved as well.We analyse and discuss the intrinsic mechanism for the enhancement of ionic conductivity of PEO composite electrolytes by adding mosoporous materials containing lithium ions using XREK TGA, DSC, IR and PLM methods. The crossed polarizers microscope (PLM) is employed to investigate the crystal micrographs of PEO polymer electrolytes for the first time. The results show that the mesoporous grains not only hinder the ordered arrange of PEO chains, but also have the ability to fine crystal and increase the fraction of the amorohous phase in solid polymer electrolyte. The decrease of the glass-transition temperature (Tg) and melting temperature (Tm) indicates the increase of the polymer chains flexibility.It was proposed that the affect between Li+ in mesoporous fillers and CIO4’ can promote the dissociation of Li+-C104’ in PEO polymer electrolyte , and result in the increase of transference number of Li+, therefore enhance the ionic conductivity. 2 For the first time lithium anode was charged by bi-directional pulse current instead of traditional direct current (DC) to suppress the formation of lithium dendrites. When the lithium electrode was charged by pulse current (0.2mA/cm2), there was no dendrite formed in 7 h and the lithium surface kept smooth. However, obvious dendrites formed on the surface of lithium electrode when it was charged by DC at the same current density for 30 min. Additionally, the lithium anode charged by pulse current had better coulombic efficiency than that of lithium anode charged by DC. The EIS was used to confirm the phenomena from the view of the lithium surface area changes during these processes. This result exhibits it is a new way to suppress the lithium dendrites during the charging process, and it is beneficial to更多还原