Fast Lithium-Ion Transportation in Crystalline Polymer Electrolytes

Fast lithium-ion transportation is found in the crystalline polymer electrolytes, α-CD-PEO_n/Li⁺ (n=12, 40), prepared by self-assembly of α-cyclodextrin (CD), polyethylene oxide (PEO) and Li⁺ salts. A detailed solid-state NMR study combined with the X-ray diffraction technique reveals the unique structural features of the samples, that is, a) the tunnel structure formed by the assembled CDs, providing the ordered long-range pathway for Li⁺ ion transportation; b) the all-trans conformational sequence of the PEO chains in the tunnels, attenuating significantly the coordination between Li⁺ and the EO segments. The origin of the fast lithium-ion transportation has been attributed to these unique structural features. This work demonstrates the first example in solid polymer electrolytes (SPEs) for “creating” fast ion transportation through material design and will find potential applications in the design of new ionconducting SPE materials.