高比容量锂硫电池电极材料的制备及性能改进的研究

发布时间：2018-05-14 17:26

  本文选题：Li-S电池 + 碳纸阻隔层　； 参考：《青岛科技大学》2017年硕士论文

【摘要】：锂硫电池的理论能量密度高达2600 Wh kg-1,作为最具竞争力的下一代可充电电池之一,锂硫电池引起了极大的关注。除了高能量密度外,硫单质作为锂硫电池的阴极还有自然界中储存丰富,成本低和无毒的优点,开发此类电池具有巨大的优势。但受现在研究水平和技术水平的限制,锂硫电池中现存的问题还无法得到彻底的解决,其中“穿梭效应”被认为是锂硫电池实际应用的主要障碍之一,可导致锂硫电池容量的快速衰减和库仑效率低。本研究针对“穿梭效应”问题,提出并制备了多功能碳纸和新型凝胶聚合物电解质(PEGPE),从而显著改善了锂硫电池性能。(1)针对“穿梭效应”,我们研究了多功能碳纸阻隔层。以导电剂和金属氧化物混合材料为涂层修饰的碳纸制备多功能碳纸阻隔层,将其插在正极和隔膜之间,作为溶解的多硫化物阻挡层。配备多功能碳纸阻隔层的锂硫电池展现出优异的长循环性能(0.5 C下,初始放电比容量1250 mAh g-1,400次循环后放电比容量为900 mAh g-1),通过扫描电镜和元素分布图谱分析,证明了多功能碳纸阻隔层对多硫化物具有阻挡作用。(2)为解决“穿梭效应”问题,本文研究并制备了一种新型凝胶电解质PEGPE来替代锂硫电池中传统的液态电解质。该凝胶电解质以聚乙烯(PE)隔膜为支撑体,通过季戊四醇四丙烯酸酯(PETEA)与己二酸乙烯基酯(Ester)聚合形成。以PEGPE为电解质的锂硫电池显示出优异的循环稳定性,在0.5 C电流密度下300次循环后,保持343 mAh g-1可逆放电比容量,同时具有高于92%的库仑效率。该锂硫电池的良好的循环性能主要源于PEGPE封闭多硫化物梭和非常稳定的电极与电解质的界面。
[Abstract]:The theoretical energy density of lithium-sulfur batteries is as high as 2600 Wh 路kg -1. As one of the most competitive next generation rechargeable batteries, lithium-sulfur batteries have attracted great attention. In addition to high energy density, sulfur as the cathode of lithium-sulfur batteries has the advantages of rich storage, low cost and non-toxic in nature, so the development of this kind of batteries has great advantages. However, limited by the current research level and technical level, the existing problems in lithium-sulfur batteries can not be completely solved, among which "shuttle effect" is considered as one of the main obstacles to the practical application of lithium-sulfur batteries. It can lead to rapid attenuation of lithium-sulfur battery capacity and low Coulomb efficiency. In order to solve the problem of "shuttle effect", the multifunctional carbon paper and a new gel polymer electrolyte PEGPEN were proposed and prepared in this study, which significantly improved the performance of lithium-sulfur batteries. (1) in view of the "shuttle effect", we studied the multifunctional carbon paper barrier layer. The multifunctional carbon paper barrier layer was prepared by carbon paper coated with conductive agent and metal oxide mixture. The barrier layer was inserted between the positive electrode and the diaphragm as the dissolved polysulfide barrier layer. The lithium-sulfur battery equipped with multifunctional carbon-paper barrier layer showed excellent long cycle performance at 0.5C. The initial discharge specific capacity of 1250 mAh g-1400 cycles was 900 mAh g-1g ~ (-1), which was analyzed by scanning electron microscopy (SEM) and elemental distribution spectra. In order to solve the problem of "shuttle effect", a new gel electrolyte, PEGPE, was studied and prepared to replace the traditional liquid electrolyte in lithium-sulfur battery. The gel electrolyte was prepared by polymerization of pentaerythritol tetraacrylate (PETEAA) and vinyl adipate (Ester). The lithium-sulfur battery with PEGPE as electrolyte showed excellent cycle stability. After 300 cycles at 0.5C current density, the specific capacity of reversible discharge was maintained at 343 mAh g ~ (-1) and the Coulomb efficiency was higher than 92%. The good cycling performance of the lithium-sulfur battery is mainly due to the PEGPE closed polysulfide shuttles and the very stable interface between electrode and electrolyte.
【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】：TM912
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本文编号：1888812