储能科学与技术 ›› 2015, Vol. 4 ›› Issue (3): 273-277.doi: 10.3969/j.issn.2095-4239.2015.03.005

• 研究及进展 • 上一篇    下一篇

PEO基Li1.5Al0.5Ge1.5(PO4)3固体复合电解质的制备

余涛, 谢凯, 韩喻, 王珲   

  1. 国防科学技术大学航天科学与工程学院,湖南 长沙 410073
  • 收稿日期:2014-10-20 出版日期:2015-06-19 发布日期:2015-06-19
  • 通讯作者: 谢凯,教授,博士生导师,研究方向为高能量密度锂离子二次电池及材料、锂硫二次电池及材料、固体薄膜电池、新型薄膜太阳能电池、光电功能材料等,E-mail:kai_xie@163.com。
  • 作者简介:余涛(1990—),男,硕士研究生,研究方向为固体电解质,E-mail:503323354@qq.com

Preparation and characterization of PEO based Li1.5Al0.5Ge1.5(PO4)3 solid composite electrolyte

YU Tao, XIE Kai, HAN Yu, WANG Hui   

  1. Department of Material Science and Engineering, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073, Hunan, China
  • Received:2014-10-20 Online:2015-06-19 Published:2015-06-19

摘要: 以聚环氧乙烷(PEO)为黏结剂,离子导电性的Li1.5Al0.5Ge1.5(PO4)3(LAGP)为主相,乙腈为溶剂,按照EO/Li,摩尔比为13,变化LiN(CF3SO2)2(LiTFSI)中Li+ 与LAGP中Li+ 的比例,通过溶液浇注法制备得到LAGP-PEO(LiTFSI)固体复合电解质。用X射线衍射、扫描电镜(SEM)和电化学阻抗(EIS)等方法对固体复合电解质的形貌、结构和电导率进行表征。结果表明,LAGP可与PEO(LiTFSI)部分络合并均匀分散于PEO(LITFSI)内,整个体系内存有三个主体相,即PEO(LiTFSI)的复合相、LAGP晶相以及PEO与两种锂盐的过渡相。通过阻抗谱图发现,当质量比w(LAGP)∶w(PEO)=6∶4时,LAGP-PEO(LiTFSI) 固体复合电解质具有最高的室温电导率,为2.68×10-5 S/cm,在333 K时,达到1.86×10-4 S/cm,接近LAGP的电导率水平。这说明固体复合电解质中加入LAGP即降低了PEO的结晶度,LAGP自身的电导率也有一定贡献。

关键词: 固体复合电解质, PEO, LAGP, 电导率

Abstract: PEO-based solid composite electrolyte with the fast ion conductor LAGP(Li1.5Al0.5Ge1.5(PO4)3) as a main ionic conductive component and PEO as the binder were prepared by the solution casting method with fixed n(EO)/n(Li)=13, but varying ratio of LiTFSI to LAGP. The structure and morphology of the solid composite electrolyte were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The conductivity of LAGP-PEO(LiTFSI) electrolyte was analyzed by electrical impedance spectroscopy (EIS). The results show that LAGP is partially complexed with PEO(LiTFSI) and homogeneously distributed in PEO(LiTFSI). Three phases are present, a pure crystalline LAGP phase, amorphous PEO(LiTFSI) phase and a transition phase of the LAGP particles and amorphous PEO(LiTFSI). With w(LAGP)∶w(PEO)=6∶4, the optimal ionic conductivity for LAGP-PEO(LiTFSI) solid composite electrolyte is 2.68×10-5 S/cm at room temperature and 1.86×10-4 S/cm at 373 K which is close to the LAGP. It means that the LAGP addition contributes to the improvements of ionic conductivity not only by prohibiting crystallization but also due to its own ionic conductivity.

Key words: solid composite electrolyte, PEO, LAGP, conductivity

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