Abstract
The first family of lithium-ion electrolytes based on thermotropic liquid crystalline (LC) cyclodextrin (CD) is reported. The new electrolytes consist of composites of self-Assembling and environment-friendly amphiphilic β-CDs with lithium bistrifluoromethanesulfonimidate (LiTFSI). The unique geometry of the CD scaffold allows for efficient control of the amphiphilicity of the molecule through chemical derivatizations. The introduction of non-polar alkyl chains at the primary face of CD and multiple short and polar nitrile-Terminated tetraethylene glycol chains at the other face provides a new class of LC materials capable of self-organization into homeotropically-Aligned smectic mesophases, which retain long-range order over a wide temperature window. The assembly of numerous ethoxy groups at the secondary face of CD serves as an elegant pre-organization of the ion-chelating groups to form two-dimensional ion-conducting pathways, facilitating the directional motion of metal ions. Studies of several LC composites with LiTFSI have revealed promising thermal stability and ionic conductivity. Solid-state NMR studies have uncovered an activation energy of 0.14 eV for lithium diffusion, while cyclic voltammetry confirmed the composites remain electrochemically stable over a potential range of up to ∼3 V versus Li/Li+. These results demonstrate the great potential of this new class of organic electrolytes for different metal ions.
Original language | English |
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Pages (from-to) | 12201-12213 |
Number of pages | 13 |
Journal | Journal of Materials Chemistry A |
Volume | 7 |
Issue number | 19 |
DOIs | |
Publication status | Published - 2019 |