【作者】 郭来宾；

【导师】 魏守强；

【作者基本信息】 沈阳理工大学 ， 应用化学， 2008， 硕士

【摘要】 目前凝胶聚合物锂离子电池的生产虽已经具有规模,但仍存在着两个方面的主要问题:一是在电池性能方面凝胶电解质的电导率与液态电解质相比仍然偏低,快速充放电性能和低温性能较差。二是在目前凝胶电解质的制备方法中,不论溶液浇铸成膜法还是美国Bellcore法,共同的问题都是制造工序烦琐,工艺相当复杂,生产成本高。针对凝胶聚合物电解质以上两方面的问题,本论文采用现场热聚合法制备了凝胶聚合物电解质。该方法是先将一定比例的单体、交联剂、引发剂及液态电解液混合配制成前驱体溶液,再将前驱体溶液热引发聚合,最后生成凝胶聚合物电解质。因而,本论文主要工作内容为凝胶电解质体系的选择、现场热聚合物工艺条件的优化及前驱体溶液中各组分的配比优化,并通过对凝胶电解质性能的测试和表征来研发出适合现场热聚合工艺的凝胶电解质,从而实现聚合物锂离子电池制备工艺的改进。本论文通过对凝胶时间及电导率等性能的考察,确定了凝胶聚合物电解质体系为甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)和三乙二醇二甲基丙烯酸酯(TEGDMA),现场热聚合工艺的工艺条件为热聚合工艺III。本论文对凝胶各组分进行了改进和优化,找到了前驱体溶液最佳配比,制备了性能良好的凝胶电解质,室温电导率最高达8.16mS/cm。本论文通过扫描电子显微镜观察了聚合物基体的网状多孔结构;用电化学阻抗谱研究了凝胶电解质的电导率及温度、时间等影响电导率的各种因素;用线性扫描测得电解质的电化学窗口能达到6V以上;通过热重和差热法考察了凝胶电解质的热力学性能,结果显示凝胶电解质具有良好的热力学稳定性;通过电位阶跃法研究了锂离子迁移数随电解液含量的大致变化趋势;通过电解质与锂片之间的界面阻抗谱的测试,研究了凝胶电解质的界面稳定性;另外还通过压力破碎剂测试了不同聚合物含量电解质机械强度的变化情况。更多还原

【Abstract】 Currently the gel polymer lithium ion batteries have already had a scale, but the production still have two key problems: one problem is the ionic conductivity of the gel polymer electrolyte (GPE) which is still lower than the liquid electrolyte,and that causes the fall of high rate discharge and low temperature performance of lithium battery. The other one is the making methods of the gel polymer electrolyte (GPE) that not only solution casting method but also the American Bell-core method have some common problems, such as the complicated process and the high production cost.Focusing on the two problems, this paper adopts the method of in-situ thermal polymerization to fabricate gel polymer electrolyte. Firstly take out a certain rate of the monomers, cross-linking agent, initiator and liquid electrolyte, then mix them to prepare the precursor solution. Secondly heat the precursor solution to initiate a polymerization reaction, and at last the precursor solution turns to gel and the preparation of GPE is completed. The paper mainly has studied the system of the GPE , the excellent progress condition and the best ratio of component in precursor solution . By testing the performance of the GPE the paper tries to find a excellent gel polymer system and technical parameters in order to realize the in-situ polymerization in lithium ion battery and achieve the improvement of the making progress of the polymer lithium ion battery .In this paper a excellent gel polymer system including methyl methacrylate (MMA), butyl acrylate(BA) and triethylene glycol dimethylacrylate (TEGDMA) has been found, and the best progress condition is thermal polymerization III.In this paper the sort and weights of the components of the gel electrolyte has been optimized, and a gel polymer electrolyte with excellent performance has been prepared, whose ion conductivity reaches 8.16 mS/cm .The porous structure of the polymer base has been observed by SEM .The ionic conductivity of the GPE has been tested using AC impedance spectra .The factors such as temperature and time influencing the performance of the GPE has been analyzed too. There is no chemical reaction since the scan potential has 6.0V by technique of linear sweep voltammetry. It proves that the GPE has a good performance of electrochemical stability. The TG-DTA spectra both reveals that the GPE has a good thermodynamics stability. The lithium ion transference number of the GPE has been tested by using constant potential step, and the relationship between the ion transference number and the various contents of liquid electrolyte has been approximately studied. The paper also has studied the interfacial stability between GPE and lithium slice by using AC interfacial impedance spectra. Moreover, the mechanical strength of GPE with various contents of liquid electrolyte has been approximately studied by pressure testing machine .更多还原