Effects of 1-butyl-3-methyl imidazolium trifluoromethanesulfonate ionic liquid in poly(ethyl methacrylate)/poly(vinylidenefluoride-co-hexafluoropropylene) blend based polymer electrolyte system

In this work, 1-butyl-3-methyl imidazolium trifluoromethanesulfonate (BMITf) is employed as ionic liquid in polymer blend electrolyte system based on poly(ethyl methacrylate) (PEMA) and poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP) in the weight ratio of 70 to 30. The films were prepared by solution casting. Lithium trifluoromethanesulfonate (LiTf) is the lithium ion (Li+) provider. Addition of BMITf into the optimized PEMA/PVdF-HFP-LiTf composition increased the ionic conductivity of the system. The highest room temperature ionic conductivity of 8.59 x 10(-5) S cm(-1) was exhibited by PEMA/PVdF-HFP-LiTf containing 60 wt.% BMITf. Vibrational studies by FTIR show that the imidazolium cation (BMI+) interacts with the oxygen atoms in C=O and C-O-C groups of PEMA, and also fluorine atoms in CF2 groups of PVdF-HFP. Addition of BMITf into the PEMA/PVdF-HFP-LiTf system increases the amount of free ions leading to improvement in the ionic conductivity. The thermal stability of the polymer electrolytes is improved to above 275 degrees C by the addition of BMITf. (C) 2014 Elsevier Ltd. All rights reserved.