FTIR Spectroscopic Studies of PEO-based Polymer Electrolyte with Ionic Liquid

Polymer electrolytes based on poly(ethylene oxide)(PEO) was prepared using LiTFSI as lithium salt and doping with 1-butyl-3-methylimidazolium hexaflurophosphate(BMIMPF6) by solution casting method.The addition of BMIMPF6 resulted in an increase of the ionic conductivity.When the amount of the ionic liquid is 40%,the ionic conductivity could reach 1.80×10-4 S/cm at 40 ℃.The samples were explored by emission FTIR spectroscopy at elevated temperatures,which illustrated the dependence of crystalline PEO phase on temperature.Based on results of SEM,XRD,transmission FTIR and emission FTIR,the effect of ionic liquid on the ionic conductivity was analyzed.It was revealed that the ionic liquid decreased cystallinity of the polymer,and resulted in the increase of ionic conductivity.The study has demonstrated that the FTIR spectroscopy is an important method for investigations of lithium batteries.