Speciation analysis for next generation battery electrolyte solutions: Spectrothermodynamics - Lithium Ion solvation in ionic liquids

Abstract

Speciation analysis is defined as identifying and/or measuring the quantities of one or more individual chemical species in a sample; it also involves evaluations of the species distribution and molecular structure of the species, and even their conformers. Raman/IR vibration spectroscopy and neutron/X-ray scattering experiments can reveal not only molecular and/or liquid structures, but also species formation equilibria thermodynamically. We propose that such techniques can be called “Spectrothermodynamics”. In this contribution, we show this speciation analysis applied to lithium ion solvation in the bis-(trifluoromethanesulfonyl)amide and the bis-(fluromethanesulfonyl)amide based ionic liquids, based on the spectrothermodynamics. We also describe ionic liquids specific central metal ion stabilization by the ionic liquid consisting of cations at the metal ion second sphere and the solvation structure equilibria evaluated thermodynamically.