Ionic Association in CH3-(CH2-CF2) n -CH3(PVDF)-Li+-(CF3SO2)2N- for n = 1, 4: A Computational Approach.

Abstract

The ionic conductivity of solid polymer electrolytes is governed by the ionic association caused by the polymer···Li+ and the anion···Li+ interactions. We performed the density functional calculation to analyze the molecular interactions in the CH3–(CH2–CF2)n–CH3–Li+–(CF3SO2)2N– for n = 1,4 systems. The gauche conformation is predicted in the lowest energy conformer of pure polymer except for n = 1. The lithium coordination number with the polymer is changed from 3 to 2 in the presence of anion for n = 2, 4 systems. The consequences of the Li+ ion and Li+–(CF3SO2)2N– to the vibrational spectrum are studied to understand the ionic association at the molecular level.