新型聚硅氧烷接枝聚氧化乙烯类固体电解质的制备与电化学性能
发布时间：2018-12-14 21:53
【摘要】：电解质作为锂电池的关键材料之一,对电池的功率密度、循环性、安全性等具有重要影响。目前常用的液体电解质由于易燃、易漏、易挥发的特性很容易造成安全问题,而固体聚合物电解质是一个很好的解决方案。但是固体聚合物电解质存在着电导率较低、锂离子迁移数较低的缺点。基于此,本文制备了聚硅氧烷接枝聚氧化乙烯类固体电解质,并研究了电解质的电化学性能。首先通过硅氢加成反应合成了聚氧化乙烯接枝聚硅氧烷。然后将聚合物与双烯丙基聚乙二醇发生交联反应,制备了固体聚合物电解质(SCPE)。通过交流阻抗法(EIS)研究了锂盐浓度对电导率的影响,结果表明当EO:Li为20:1时,电解质常温下电导率达到1.74×104S/cm。通过线性扫描伏安法(LSV)考察了电解质的电化学稳定性,结果表明电解质化学窗口达到5V(vs.Li+/Li)。基于此电解质的LiFePO4/SPE/Li电池在0.15C倍率下循环30圈后,电池充放电比容量还有130mAh/g左右。加入丁二腈后,电解质的电导率和电化学窗口均得到提高。为提高锂离子迁移数,首先合成了一种新型的4-苯乙烯磺酰全氟丁基磺酰亚胺锂盐,其中-S02-N(-)-S02-C4F9-的电荷离域化程度较高,与锂离子之间的作用力弱,可提高可移动的锂离子数目。通过硅氢加成反应将阴离子和聚氧化乙烯接枝到聚硅氧烷骨架上,然后交联成单离子导电固体电解质(SPE)。通过核磁和红外证实了锂盐单体和聚合物的结构。通过DSC和TG表征了电解质的热性质,结果表明电解质具有较低的玻璃化温度和较高的热稳定性。通过LSV和EIS研究了电解质的电化学性能。当EO:Li为28:1时,电解质在在30 ℃下电导率为3.77×10-5S/cm。电解质电化学窗口达到5.2V(vs.Li+/Li)。此外,该聚合物电解质的锂离子迁移数达到0.80。
[Abstract]:Electrolyte, as one of the key materials of lithium battery, has an important effect on power density, cycle and safety of the battery. At present, the common liquid electrolyte is easy to cause safety problems because of its flammable, leaky and volatile characteristics. Solid polymer electrolyte is a good solution. However, solid polymer electrolytes have the disadvantages of low conductivity and low lithium ion mobility. Based on this, polysiloxane grafted poly (ethylene oxide) solid electrolyte was prepared and its electrochemical properties were studied. Firstly, polyoxyethylene grafted polysiloxane was synthesized by hydrosilylation. The solid polymer electrolyte (SCPE). Was prepared by crosslinking the polymer with diallyl polyethylene glycol. The influence of lithium salt concentration on conductivity was studied by AC impedance (EIS). The results show that the conductivity of electrolyte reaches 1.74 脳 10 ~ 4 S / cm ~ (-1) at normal temperature when EO:Li is 20:1. The electrochemical stability of electrolyte was investigated by linear scanning voltammetry (LSV). The results showed that the electrolyte chemical window reached 5V (vs.Li / Li). The charge / discharge specific capacity of LiFePO4/SPE/Li battery based on this electrolyte is about 130mAh/g after 30 cycles at 0.15C rate. The conductivity and electrochemical window of the electrolyte increased with the addition of succinonitrile. In order to improve the mobility of lithium ions, a new lithium salt of 4-styrene-sulfonyl perfluorocarbon Ding Ji was synthesized, in which the charge of -S02-N (-) -S02-C4F9- was highly delocalized, and the interaction force between it and lithium ion was weak. The number of removable lithium ions can be increased. The anions and polyoxyethylene were grafted onto the polysiloxane skeleton by hydrosilylation reaction, and then crosslinked to form a single ion conductive solid electrolyte (SPE). The structure of lithium salt monomer and polymer was confirmed by NMR and IR. The thermal properties of the electrolyte were characterized by DSC and TG. The results showed that the electrolyte had lower glass transition temperature and higher thermal stability. The electrochemical properties of electrolytes were studied by LSV and EIS. When EO:Li is 28:1, the conductivity of electrolyte is 3.77 脳 10 ~ (-5) S / cm ~ (-1) at 30 鈩，
本文编号：2379380
[Abstract]:Electrolyte, as one of the key materials of lithium battery, has an important effect on power density, cycle and safety of the battery. At present, the common liquid electrolyte is easy to cause safety problems because of its flammable, leaky and volatile characteristics. Solid polymer electrolyte is a good solution. However, solid polymer electrolytes have the disadvantages of low conductivity and low lithium ion mobility. Based on this, polysiloxane grafted poly (ethylene oxide) solid electrolyte was prepared and its electrochemical properties were studied. Firstly, polyoxyethylene grafted polysiloxane was synthesized by hydrosilylation. The solid polymer electrolyte (SCPE). Was prepared by crosslinking the polymer with diallyl polyethylene glycol. The influence of lithium salt concentration on conductivity was studied by AC impedance (EIS). The results show that the conductivity of electrolyte reaches 1.74 脳 10 ~ 4 S / cm ~ (-1) at normal temperature when EO:Li is 20:1. The electrochemical stability of electrolyte was investigated by linear scanning voltammetry (LSV). The results showed that the electrolyte chemical window reached 5V (vs.Li / Li). The charge / discharge specific capacity of LiFePO4/SPE/Li battery based on this electrolyte is about 130mAh/g after 30 cycles at 0.15C rate. The conductivity and electrochemical window of the electrolyte increased with the addition of succinonitrile. In order to improve the mobility of lithium ions, a new lithium salt of 4-styrene-sulfonyl perfluorocarbon Ding Ji was synthesized, in which the charge of -S02-N (-) -S02-C4F9- was highly delocalized, and the interaction force between it and lithium ion was weak. The number of removable lithium ions can be increased. The anions and polyoxyethylene were grafted onto the polysiloxane skeleton by hydrosilylation reaction, and then crosslinked to form a single ion conductive solid electrolyte (SPE). The structure of lithium salt monomer and polymer was confirmed by NMR and IR. The thermal properties of the electrolyte were characterized by DSC and TG. The results showed that the electrolyte had lower glass transition temperature and higher thermal stability. The electrochemical properties of electrolytes were studied by LSV and EIS. When EO:Li is 28:1, the conductivity of electrolyte is 3.77 脳 10 ~ (-5) S / cm ~ (-1) at 30 鈩，
本文编号：2379380
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