Single-ion conducting polymer electrolytes have attracted great attention as safe alternatives to liquid electrolytes in high energy density lithium-ion batteries. Herein, we report the first example of a crystalline anionic helical polymer as a single lithium-ion conducting solid polymer electrolyte (SPE). Single-crystal X-ray analysis shows that the polymer folds into densely packed double helices, with bundles of unidirectional negatively charged channels formed that can facilitate lithium-ion transportation. Such a helical covalent polymer (HCP) exhibits excellent room temperature lithium-ion conductivity (1.2 × 10−3 S·cm−1) in the absence of external lithium salts, a high transference number (0.84), low activation energy (0.14 eV), and a wide electrochemical stability window (0.2–5 V). We found that nonflammable, nonvolatile ionic liquid can serve as a solvating medium and excellent conductivity enhancer (>1000 times increase). These ion-conducting properties are comparable to the best polyethylene oxide-based polymer electrolytes mixed with lithium salts. Finally, we show that the solvated HCP SPE enables the reversible cycling of an all-solid-state cell prepared with a high-voltage NMC 811 cathode. Our study opens up new possibilities for developing next-generation high-performance solid-state electrolytes.
CITATION STYLE
Hu, Y., Dunlap, N., Long, H., Chen, H., Wayment, L. J., Ortiz, M., … Zhang, W. (2021). Helical Covalent Polymers with Unidirectional Ion Channels as Single Lithium-Ion Conducting Electrolytes. CCS Chemistry, 3(12), 2762–2770. https://doi.org/10.31635/ccschem.021.202101257
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