Exploring the energetics of the lithium ion-organic carbonate interaction: A FTIR and DFT study

Lithium ion batteries have become a growing concern due to their inherent problems of safety and performance. To this end, the possibility of replacing the highly flammable carbonate-based solvents of the electrolyte with safer analogues is being explored. However, the techniques used to predict which solvents may produce a good electrolyte require a large amount of testing. To overcome this problem, it is possible to use well established computational methods, though these methods require proper validation. In this study, the lithium ion-solvent interaction energies predicted from density functional theory (DFT) were compared with experimental values derived from infrared (IR) spectroscopy. The energetics is derived from IR experiments which measure the propensity of a cyclic carbonate to solvate the lithium ion in mixed solvent solutions. The results show good agreement between experiments and theory which validates the use of DFT to predict the solvent-ion interaction strength.