Ionic Association in CH₃–(CH₂–CF₂)_<i>n</i>–CH₃(PVDF)–Li⁺–(CF₃SO₂)₂N^– for <i>n</i> =\n1, 4: A Computational Approach

Abstract

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