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

A new category of crystalline polymer electrolyte prepared by the supramolecular self-assembly of polyethylene oxide (PEO), alpha-cyclodextrin (alpha-CD), and LiAsF6 is reported. The polymer electrolyte consists of the nanochannels formed by alpha-CDs in which the PEO/Li+ complexes are confined. The nanochannels formed by alpha-CD provide the pathway for the directional motion of Li+ ions and at the same time prevent the access of the anions by size exclusion, resulting in good separation of the Li+ ions and the anions. The conductivity of the reported material is 30 times higher than that of the comparable PEO/Li+ 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+ ions was studied and correlated to the ionic conductivity of the material.