多元醇类凝胶因子的溶剂效应及其在锂硫电池中应用研究

发布时间：2018-03-19 03:17

本文选题：山梨醇单缩醛衍生物　切入点：低分子量凝胶因子　出处：《天津大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文合成了两种山梨醇单缩醛型低分子量凝胶因子2,4-(3,4-二氯苯亚甲基)-D-山梨醇(DCBS)和2,4-(3,4-二甲基苯亚甲基)-D-山梨醇(DMBS)。对于凝胶因子DCBS的混合溶剂效应的研究发现,DCBS能溶解在乙醇溶剂中,而当向体系中加入一定体积分数的甲基环己烷时,能形成稳定的凝胶。SEM研究表明混合溶剂组成会改变聚集体的微观形貌,并与呈现的宏观凝胶能力变化相一致。FT-IR和XRD研究结果表明,分子间的氢键作用是分子自组装形成凝胶的主要驱动力,且不同混合溶剂组成会影响聚集体的堆积方式。Flory-Huggins溶解度参数进一步解释了单组分凝胶因子的二元混合溶剂效应。基于DCBS在其它不同混合溶剂体系中的凝胶性能,利用Flory-Huggins溶解度参数建立了DCBS的凝胶化预测模型,实现了DCBS在未测试混合溶剂体系中的凝胶行为预测,拓宽了Flory-Huggins参数的应用范围。利用凝胶因子DMBS制备了1.0mol/L LITFSI/DME:DOL(1:1,v/v)溶液的凝胶电解质,并尝试将其应用于锂硫电池中。所制备的凝胶电解质较稳定,凝胶-溶胶相转变温度大于电池的正常使用温度。电化学测试表明凝胶电解质与液态电解质有相似的电化学行为。凝胶电解质一定程度上能减缓放电过程产生的中间产多硫化物在液态电解质中的溶解及穿梭,减缓对锂极片的腐蚀,进而提高硫活性材料的利用率和电池的充放电循环性能。
[Abstract]:In this paper, two kinds of sorbitol monoacetal type low molecular weight gel factor 24-dichlorobenzene methylene--Dsorbitol (DCBSs) and 2-dimethylene methylene-4-dimethylenesulfonate (DMBSs) have been synthesized. The study on the mixed solvent effect of the gel factor DCBS shows that DCBs can dissolve. In ethanol, When a certain volume fraction of methylcyclohexane was added to the system, a stable gel. SEM study showed that the composition of the mixed solvent changed the microstructure of the aggregates. The results of FT-IR and XRD show that the hydrogen bond between molecules is the main driving force of self-assembly gel. The solubility parameter of Flory-Huggins further explains the binary mixed solvent effect of one-component gel factor. Based on the gel properties of DCBS in other mixed solvents, The gelation prediction model of DCBS was established by using the solubility parameter of Flory-Huggins, the gel behavior of DCBS in untested mixed solvent system was predicted, and the application range of Flory-Huggins parameter was broadened. The gel electrolyte of 1.0 mol / L LITFSI / DME: DME: 1: 1 v / v / v) solution was prepared by using the gel factor DMBS. The gel electrolyte prepared by this method is stable. The electrochemistry test showed that the gel electrolyte and liquid electrolyte had similar electrochemical behavior. The gel electrolyte could slow down the discharge process to some extent. Dissolution and shuttling of intermediate polysulfides in liquid electrolytes, The corrosion rate of lithium electrode is reduced, and the utilization rate of sulfur active material and the charge / discharge cycle performance of the battery are improved.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O648.17;TM912

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