应用化学 ›› 2011, Vol. 28 ›› Issue (01): 48-54.DOI: 10.3724/SP.J.1095.2011.00251

• 研究论文 • 上一篇    下一篇

含烷氧磺酸锂盐及对称星形醚的聚环氧乙烷基聚合物电解质的制备及电化学性能

古宁宇*,余佃宝,谢媛媛,杨震宇,张荣斌,刘峰   

  1. (南昌大学化学系 南昌 330031)
  • 收稿日期:2010-04-30 修回日期:2010-06-18 出版日期:2011-01-10 发布日期:2011-01-10
  • 通讯作者: 古宁宇,教授; Tel/Fax:0791-3969247; E-mail:nygu@ncu.edu.cn; 研究方向:电化学
  • 基金资助:
    电分析化学国家重点实验室课题资助(2008004)

Preparation and Electrochemical Performance of Pentaerythritol Tetrakis(2-methoxyethyl ether) Based Lithium Methoxy Oligo(oxyethylene) Sulfate Polymer Electrolytes

GU Ning-Yu*, YU Dian-Bao, XIE Yuan-Yuan, YANG Zhen-Yu, ZHANG Rong-Bin, LIU Feng   

  1. (Department of Chemistry,Nanchang University,Nanchang 330031)
  • Received:2010-04-30 Revised:2010-06-18 Published:2011-01-10 Online:2011-01-10

摘要:

合成了低聚度烷氧磺酸锂盐(LiSA(EO)n)和对称星形醚(STEO)增塑剂,并制备了聚环氧乙烷(PEO)基聚合物电解质。 研究了PEO16+LiSA(EO)n体系的锂离子迁移数和电导率与锂盐结构的关系,实验结果表明,LiSA(EO)n代替LiClO4作为锂盐时,其电导率得到提高,而且聚合物电解质的锂离子迁移数随着烷氧磺酸锂盐阴离子体积的增大而增加,并且其中PEO16+LiSA(EO)2体系的锂离子迁移数达到0.35。 STEO可明显地提高PEO16-LiSAEO-STEO体系的电导率,PEO16-LiSAEO-20%STEO室温电导率可达到0.5×10-4 S/cm。 通过DSC实验结果表明,STEO的加入,可有效降低聚合物电解质体系的熔融温度和结晶度,PEO16-LiSAEO-20%STEO电化学稳定窗口在4.4 V以上,可满足锂电池的应用要求。

关键词: 聚合物电解质, 磺酸锂盐, 锂离子迁移数

Abstract:

Lithium methoxy oligo(oxyethylene) sulfate(LiSA(EO)n) and pentaerythritol tetrakis(2-methoxyethyl-ether)(STEO) were synthesized and used for the preparation of polyethylene oxide(PEO) based polymer electrolytes. All solid-state polymer electrolytes PEO-LiSA(EO)n and PEO-LiClO4 were obtained by the solvent casting method and the ionic conductivities and lithium ion transference numbers were measured by using ac impedance and steady state current methods respectively. The influences of lithium salt structure on lithium ion transference numbers and ionic conductivities of polymer electrolytes were studied. Results showed that, comparing with LiClO4, LiSA(EO)n could enhance the ionic conductivity of polymer electrolytes and ionic conductivity decreased with increasing size of anion of lithium salt. Lithium ion transference numbers increased with increasing size of anion of lithium salt, and achieved a relatively high value of 0.35 when (PEO16+LiSA(EO)2) was used. Composed polymer electrolytes(CPEs) PEO16-LiSAEO-STEO were prepared and the effects of addition of STEO on ionic conductivities were discussed. The experimental results showed that the addition of STEO could improve the ionic conductivity of the composited polymer electrolytes effectively, the ionic conductivity of PEO16-LiSAEO-20%STEO achieved 0.5×10-4 S/cm under 25 ℃. The thermal properties of CPEs were investigated by DSC experiments. Results indicated that the addition of STEO could decrease the melting temperature and crystallinity of CPE, resulting in the improvement of ionic conductivity. The electrochemical stability window of PEO16-LiSAEO-20%STEO exceeded 4.4 V, which ensured the use of PEO16-LiSAEO-STEO as electrolyte materials for all solidstate rechargeable lithium ion batteries.

Key words: polymer electrolyte, lithium sulfate, lithium ion transference number

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