Transferring Lithium Ions in Nanochannels: A PEO/Li super(+) Solid Polymer Electrolyte Design

• Published in: Angewandte Chemie International Edition 2014-04, Vol.53 (14), p.3631-3635
• Main Authors: Yang, Ling-Yun, Wei, Da-Xiu, Xu, Min, Yao, Ye-Feng, Chen, Qun
• Format: Article
• Language: English
• Subjects: Anions; Categories; Dynamics; Electrolytes; Nanostructure; Pathways; Self assembly; Separation
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201307423

A new category of crystalline polymer electrolyte prepared by the supramolecular self-assembly of polyethylene oxide (PEO), [alpha]-cyclodextrin ([alpha]-CD), and LiAsF sub(6) is reported. The polymer electrolyte consists of the nanochannels formed by [alpha]-CDs in which the PEO/Li super(+) complexes are confined. The nanochannels formed by [alpha]-CD provide the pathway for the directional motion of Li super(+) ions and at the same time prevent the access of the anions by size exclusion, resulting in good separation of the Li super(+) ions and the anions. The conductivity of the reported material is 30 times higher than that of the comparable PEO/Li super(+) complex crystal at room temperature. By using state-of-art solid-state NMR spectroscopy, the structure and dynamics of the material were investigated in detail. The dynamics of the Li super(+) ions was studied and correlated to the ionic conductivity of the material. A new category of crystalline polymer electrolyte has been prepared by the supramolecular self-assembly of PEO (see picture, black), [alpha]-cyclodextrin ([alpha]-CD, blue), and LiAsF sub(6). In this polymer electrolyte, the nanochannels formed by [alpha]-CD provide the pathway for the directional motion of Li super(+) ions (colored spheres, 5 different environments) and at the same time prevent access of the anions by size exclusion, thereby resulting in good separation of the Li super(+) ions and the anions.