Structural characterization by NMR procedure of C₄C₁Pyrr TFSI doped with Lithium TFSI salt in liquid and gel states

Ionic Liquids (ILs) represent a viable option as electrolytes as many electrochemical applications such as energy storage devices due to their competitive features in contrast to the options used today due, mainly, their high ionic conductivity and wide electrochemical window. However, liquid electrolytes present important problems of safety and performance, and encapsulation in solid matrix can be a good solution to improve it. In this work, changes on the structure of the mixtures of ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (C₄C₁Pyrr TFSI) and Lithium bis(trifluoromethylsulfonyl)imide (Li TFSI) against the concentration of the salt (pure IL, 0.1 and 1.5 molal of salt addition) were studied using NMR technique. Moreover, the effect of nanoconfinement of these mixtures through gelation process was also analysed.

The salt addition does not have a significant influence in the structural arrange of the cation of the IL in both liquid and gel states, while over the gelation of the liquid sample has a result a slight slowdown of the molecular dynamics, although a liquid behaviour was observed inside the organic matrix.