固态锂空气电池用新型聚合物基复合电解质的研究

发布时间：2018-01-18 04:14

本文关键词：固态锂空气电池用新型聚合物基复合电解质的研究　出处：《青岛科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：在石油、煤、天然气等不可再生能源逐渐枯竭,环境问题日益严重的今天,发展新能源汽车产业,缓解能源和环境压力,是未来汽车产业长远发展的必然方向。锂空气电池因其巨大的理论能量密度(11140 Wh kg-1)在新一代电动汽车领域展示出重要的应用前景。无论是从计算的理论能量密度还是从实际达到的能量密度上来看,锂空气电池都是远远超过传统的镍镉电池、铅酸电池、锂离子电池等储能器件,被认为是未来电动汽车的首选高能动力电池之一。然而目前普遍应用的液态有机电解液存在漏液、易燃、容量低、副产物多等劣势,是阻碍锂空气电池发展的主要原因。近年来,聚合物电解质因其高安全性,稳定性和加工灵活性的特点有效解决上述问题。本论文通过设计并制备一系列聚合物基电解质并将其应用在锂离子电池和锂空气电池中,主要的研究内容如下:(1)通过溶液浇铸法制备了聚氨酯/纤维素基凝胶聚合物电解质(CGPE)。对其进行一系列表征后,结果证明CGPE具有较高的室温离子电导率(1.48×10-4 S cm~(-1)),宽电化学窗口(4.4 V vs Li+/Li),较高的锂离子迁移数(t+=0.68)和良好的界面稳定性。进一步地,CGPE被应用在锂离子电池表现出了出色的倍率性能和室温循环性能,200圈后依然有91%的容量保持率。CGPE被应用在锂空气电池中,依然表现出了出色的循环可逆性和低充电过电势,而且,CGPE基锂空气电池表现了非常优异的循环稳定性。(2)采用聚碳酸亚丙酯(PPC)、锂化后的全氟磺酸膜(Li-Nafion),聚甲基丙烯酸甲酯(PMMA)和氧化还原电对(TEMPO)制备成三明治‖结构的准固态聚合物电解质(QSPE)。通过对其进行结构和电化学性能的表征,结果证明QSPE具有很高的选择透过性,能有效抑制TEMPO的穿梭效应。QSPE具有相对较高的室温离子电导率和电化学窗口,保证了其具有较好的电化学性能。将其组装成锂空气电池Li/QSPE/Super P,发现该体系下的锂空气电池具有很低的充电过电势和优异的倍率性能。更重要的是,其循环稳定性非常出色,200圈后充电终止电压小于4 V,放电平台为2.6 V。通过对其副产物进行定量分析,QSPE在充放电时产生了少量的甲酸锂和乙酸锂,说明在充放电循环中QSPE能有效减少副产物的生成。
[Abstract]:In the oil, coal, natural gas and other non-renewable energy gradually depleted, environmental problems are increasingly serious today, the development of new energy automotive industry, to ease the energy and environmental pressure. It is the inevitable direction of the future automobile industry. Lithium Air Battery is 11140Wh kg-1 because of its huge theoretical energy density. In the field of new generation electric vehicles, it shows important application prospects, whether from the theoretical energy density calculated or from the energy density achieved in practice. Lithium air batteries are far more than the traditional nickel cadmium batteries, lead acid batteries, lithium ion batteries and other energy storage devices. It is considered to be one of the preferred high-energy power batteries for electric vehicles in the future. However, the liquid organic electrolyte which is widely used at present has the disadvantages of leakage, flammability, low capacity, many by-products and so on. In recent years, polymer electrolytes have become more and more safe because of their high safety. The characteristics of stability and processing flexibility effectively solve the above problems. In this thesis, a series of polymer based electrolytes were designed and prepared and applied to lithium ion batteries and lithium air batteries. The main research contents are as follows: (1) Polyurethane / cellulosic gel polymer electrolyte (CGPEE) was prepared by solution casting method and characterized by a series of methods. The results show that CGPE has high room temperature ionic conductivity of 1.48 脳 10 ~ (-4) S cm ~ (-1) and wide electrochemical window of 4.4 V vs Li / Li). Higher lithium ion mobility and good interfacial stability. Further, CGPE has shown excellent performance in lithium-ion batteries both at room temperature and at room temperature. After 200 laps, 91% of the capacity retention. CGPE was used in lithium-air batteries, still showing excellent cyclic reversibility and low rechargeable overpotential. CGPE based lithium-air battery showed excellent cycle stability. 2) Poly (propylene carbonate) and Li-Nafion (perfluorinated sulfonic acid membrane) were used. Preparation of a sandwich structure quasi solid polymer electrolyte QSPE by polymethyl methacrylate (PMMA) and redox electric pair (TEMPO). The structure and electrochemical properties were characterized. The results show that QSPE has high selective permeability and can effectively inhibit the shuttle effect of TEMPO. QSPE has relatively high ionic conductivity and electrochemical window at room temperature. It has good electrochemical performance and is assembled into Li/QSPE/Super P of lithium air battery. It is found that the lithium-air battery in this system has very low overcharging potential and excellent rate performance. More importantly, the cycle stability is excellent and the charging termination voltage is less than 4 V after 200 cycles. The discharge platform is 2.6 V. A small amount of lithium formate and lithium acetate are produced by quantitative analysis of the by-products of QSPE during charging and discharging. The results show that QSPE can effectively reduce the formation of by-products in charge and discharge cycles.
【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ317;TM912

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