Li+ transport mechanism in oligo(ethylene oxide)s compared to carbonates

被引：67

作者：

Borodin, Oleg ^{[1
]}

Smith, G. D. ^{[1
]}

机构：

[1] Univ Utah, Dept Mat Sci & Engn, Salt Lake City, UT 84112 USA

来源：

JOURNAL OF SOLUTION CHEMISTRY | 2007年 / 36卷 / 06期

关键词：

molecular dynamics simulations; electrolytes; lithium battery;

D O I：

10.1007/s10953-007-9146-1

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Molecular dynamics simulations have been performed on oligo(ethylene oxide)s of various molecular weights doped with the lithium bis(tfifluoromethanesulfonyl)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.

引用

页码：803 / 813

页数：11

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