Effect of Anions on Lithium Ion Conduction in Poly(ethylene carbonate)-based Polymer Electrolytes

Abstract

Poly(ethylene carbonate)-based polymer electrolytes with lithium salts (LiX; X = TFSI, ClO4, BF4 and PF6) were prepared, and their lithium transference numbers (t+) were measured to make comparison between different anion radius and salt concentrations. The LiTFSI electrolytes had the highest t+ and Li-ion conductivities of all samples at 80°C; these values increased with increasing salt concentration. According to the results of FT-IR measurements for all concentrated samples, the changes of band fraction, which divide at around 1720 cm−1 for carbonyl groups interact, with Li+ (C=O — Li+), are strongly related to the mobility of Li+ ions.