聚硅氧烷固体电解质及其全固态锂离子电池的制备

发布时间：2018-03-31 22:29

  本文选题：全固态锂离子电池　切入点：聚硅氧烷固体电解质　出处：《中南大学》2014年硕士论文

【摘要】：由于采用热稳定性高的聚合物固体电解质代替可燃的液态电解质,全固态聚合物锂离子电池具有更宽的工作温度范围和更好的安全性能。但是室温电导率差的问题严重影响了聚合物固体电解质在锂离子电池中的应用。本文通过对聚硅氧烷分子进行结构设计,获得了室温电导率高的聚硅氧烷电解质薄膜,并且制备出了宽温度范围的全固态锂离子电池。 通过聚甲基含氢硅氧烷与乙烯基三(2-甲氧基乙氧基)硅烷发生硅氢加成反应合成了梳形聚氧乙烯(PEO)单接枝聚硅氧烷。使用溶剂挥发法制备了含聚硅氧烷、聚偏氟乙烯和双三氟甲烷磺酰亚胺锂(LiTFSI)的电解质薄膜。当LiTFSI的含量为20wt%时,此电解质在25℃和80℃的电导率分别为5.7×10-5S cm-1和4.5×104S cm-1。 在此基础上,通过聚甲基含氢硅氧烷同时与乙烯基三(2-甲氧基乙氧基)硅烷和环[(烯丙氧基)甲基]乙烯碳酸酯反应获得了环状丙烯碳酸酯(PC)和梳形PEO双接枝聚硅氧烷,采用溶剂挥发法制备了电解质薄膜。当PC/PEO为6：4,LiTFSI含量为20wt%时,电解质在25℃的电导率为1.6×104S cm-1,相比于单接枝的电解质,提高了近2倍。基于这种电解质的LiFePO4/Li电池在25℃和100℃以1C倍率循环时,初始放电比容量可分别达到88.2mAh g-1和140mAh g-1,100圈循环后的放电比容量分别为79.8mAh g-1和130mAh g-1,展现出了优良的宽温度工作特性。
[Abstract]:Due to the use of solid polymer electrolytes with high thermal stability instead of flammable liquid electrolytes, All solid polymer lithium-ion batteries have wider operating temperature range and better safety performance. However, the problem of low conductivity at room temperature has seriously affected the application of polymer solid electrolyte in lithium ion batteries. Structural design of polysiloxane molecules, Polysiloxane electrolyte thin films with high conductivity at room temperature were obtained and all-solid-state lithium ion batteries with wide temperature range were prepared. The comb polyoxyethylene polysiloxane (PEO) grafted polysiloxane was synthesized by hydrosiloxane and vinyl trimethoxy ethoxy) silane. The polysiloxane containing polysiloxane was prepared by solvent volatilization. The electrolyte films of poly (vinylidene fluoride) and lithium trifluoromethane sulfonimide (LiTFSI) were prepared. When the content of LiTFSI was 20 wt%, the conductivities of the electrolyte were 5.7 脳 10 ~ (-5) S cm-1 and 4.5 脳 10 ~ (4) S cm ~ (-1) at 25 鈩，

本文编号：1692772