波谱学杂志 ›› 2015, Vol. 32 ›› Issue (1): 12-22.doi: 10.11938/cjmr20150102

• 研究论文 • 上一篇    下一篇

结晶型PEO8∶NaPF6聚电解质中晶区链段的运动

罗 欢1,2,梁欣苗1,2,冯继文1,王立英1*   

  1. 1. 波谱与原子分子物理国家重点实验室,武汉磁共振中心(中国科学院 武汉物理与数学研究所),湖北 武汉 430071;
    2. 中国科学院大学,北京100049
  • 收稿日期:2014-04-04 修回日期:2015-01-08 出版日期:2015-03-05 发布日期:2015-03-05
  • 作者简介:罗欢(1984-),男,湖北孝感人,博士研究生,分析化学专业. *通讯联系人:王立英,电话:027-87197794,E-mail:lywang@wipm.ac.cn.
  • 基金资助:

    国家自然科学基金资助项目(11004220,11274347).

Segmental Motion of PEO8∶NaPF6 Crystalline Polymer Electrolyte

LUO Huan1,2,LIANG Xin-miao1,2,FENG Ji-wen1,Wang Li-ying1*   

  1. 1. State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance (Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences), Wuhan 430071, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2014-04-04 Revised:2015-01-08 Online:2015-03-05 Published:2015-03-05
  • About author:*Corresponding author:WANG Li-ying, Tel: +86-27-87197794, E-mail: lywang@wipm.ac.cn.
  • Supported by:

    国家自然科学基金资助项目(11004220,11274347).

摘要:

利用固体NMR 研究了高度结晶的聚氧乙烯(PEO)/六氟磷酸钠(NaPF6)(按照氧钠摩尔比8∶1 描述为PEO8∶NaPF6,分子量Mw = 1 000 和6 000 g/mol)固体聚电解质晶区链段的结构和运动.对于纯PEO 来说,晶区链段的构象交换或大角度再取向促使其13C 粉末线形从低温的非轴对称(δ33δ22δ11)变成高温的轴对称线形(δ11 =δ22δ33).通过变温的13C 粉末线形和243 K 下的二维交换谱,PEO8∶NaPF6 晶区链段同样存在大角度再取向,且开启温度也很低(~243 K)与PEO 接近.这种长程的运动使得PEO8∶NaPF6 从低温的类轴对称(δ33δ22δ11)变成高温的轴对称线形(δ33δ22δ11),高温线形是PEO 高温线形的翻转.与其它PEO/Na(Li)固体聚电解质不同,PEO8∶NaPF6 中晶区链段与Na+络合后仍具有很高的运动性(与纯PEO 链段的运动性相当),这种高分子链段和Na+协同运动促使Na+沿PEO 分子链轴向迁移,提高电导率.

关键词: 固体核磁共振(solid-state NMR), 聚合物链段动力学, 电导率, 聚氧乙烯(PEO), PEO8∶NaPF6

Abstract:

Solid-state NMR spectroscopy was used to study the segmental motion of high-crystallinity PEO8∶NaPF6 electrolytes with different PEO molecular weights (Mw =1 000 and 6 000 g/mol, respectively). 13C-magic angle spinning (MAS) NMR spectra and static powder patterns, as well as static 2D exchange spectra, revealed that large-angle reorientation of the crystalline PEO segments in both PEO8∶NaPF6 complexes starts at a very low temperature (~243 K), similar to the case in pure crystalline PEO. At higher temperature, long-range reorientation gives rise to a well-defined high-temperature powder pattern of uniaxial chemical shift anisotropy (δ33δ22δ11), perhaps as the result of flipping of PEO. In contrast to other PEO/Na (Li) solid electrolytes, the segments in crystalline PEO8∶NaPF6 are highly mobile even when coordinated with Na+, and this is comparable with PEO. It is suggested that the segmental motion in crystalline PEO8∶NaPF6 electrolyte can enhance ion transportation along the coil, improving ionic conductivity.

Key words: solid-state NMR, polymer dynamics, ionic conductivity, PEO, PEO8∶NaPF6

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