Li + Transport Mechanism in Oligo(Ethylene Oxide)s Compared to Carbonates

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• 作者：Oleg Borodin and G. D. Smith
• 关键词：Molecular dynamics simulations ; Electrolytes ; Lithium battery
• 刊名：Journal of Solution Chemistry
• 出版年：2007
• 出版时间：June, 2007
• 年：2007
• 卷：36
• 期：6
• 页码：803-813
• 全文大小：299 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Physical Chemistry
  Industrial Chemistry and Chemical Engineering
  Geochemistry
  Oceanography
  Inorganic Chemistry
  Condensed Matter
  
• 出版者：Springer Netherlands
• ISSN：1572-8927

文摘

Molecular dynamics simulations have been performed on oligo(ethylene oxide)s of various molecular weights doped with the lithium bis(trifluoromethanesulfonyl)imide salt (LiTFSI) in order to explore the mechanism of Li+ transport in materials covering the range from liquid electrolytes to prototypes for high molecular weight poly(ethylene oxide)-based polymer electrolytes. Good agreement between MD simulations and experiments is observed for the conductivity of electrolytes as a function of molecular weight. Unlike Li+ transport in liquid ethylene carbonate (EC) that comes from approximately equal contributions of vehicular Li+ motion (motion together with solvent) and Li+ diffusion by solvent exchange, Li+ transport in oligoethers was found to occur predominantly by vehicular motion. The slow solvent exchange of Li+ in oligo(ethylene oxide)s highlights why high molecular weight amorphous polymer electrolytes with oligo(ethylene oxide)s solvating groups suffer from poor Li+ transport. Ion complexation and correlation of cation and anion motion is examined for oligoethers and compared with that in EC.