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Single‐Ion Conducting Poly(Ethylene Oxide Carbonate) as Solid Polymer Electrolyte for Lithium Batteries
Author(s) -
Meabe Leire,
Goujon Nicolas,
Li Chunmei,
Armand Michel,
Forsyth Maria,
Mecerreyes David
Publication year - 2020
Publication title -
batteries and supercaps
Language(s) - English
Resource type - Journals
ISSN - 2566-6223
DOI - 10.1002/batt.201900119
Subject(s) - ethylene carbonate , lithium (medication) , ethylene oxide , ionic conductivity , electrolyte , inorganic chemistry , materials science , lithium carbonate , oxide , polymer , chemical engineering , polymer chemistry , chemistry , ionic bonding , copolymer , ion , organic chemistry , electrode , medicine , engineering , endocrinology
Single‐ion conducting polymer electrolytes (SIPE) have attracted a lot of interest for application in high energy density lithium metal batteries. SIPEs possess lithium transport numbers close to unity, which does not provoke concentration gradients and holds the promise of limiting lithium dendrite formation. In this article, we have optimized a single‐ion polymer incorporating the most successful chemical units in polymer electrolytes, such as ethylene oxide, carbonate, and a lithium sulfonimide. This single‐ion poly(ethylene oxide carbonate) copolymer was synthesized by polycondensation between polyethylene glycol, dimethyl carbonate, and a functional diol including the pendant sulfonamide anionic group and the lithium counter‐cation. By playing with the monomer stoichiometry, the crystallinity and ionic conductivity were optimized. The best copolymer showed high ionic conductivity values of 1.2×10 −4 S cm −1 at 70 °C. Lithium interactions and mobility were studied by lithium‐pulsed field gradient, lithium diffusion, NMR relaxation time measurements, and FTIR‐ATR analysis. High lithium mobility is observed, which is due to the weakly coordinating chemical environment in the polymer and also that the sulfonamide in the SIPE adopts to a greater extent the cis conformation, which is known to promote lithium mobility. Finally, the performance of the singe‐ion conducting poly(ethylene oxide carbonate) was compared in lithium symmetric cells versus an analogous conventional salt in polymer electrolyte, showing improved performance in lithium plating and stripping.