(531a) Structure and Dynamics of Water-in-Salt Litfsi Electrolytes from First-Principles Molecular Dynamics Simulations
AIChE Annual Meeting
Wednesday, November 16, 2022 - 12:30pm to 12:50pm
Hydrogen bond analysis reveals a decrease in the number of intermolecular water-water hydrogen bonds per water molecule on increasing salt concentration. Network analysis suggests that as the salt concentration increases, the hydrogen bonding network of water molecules is disrupted, along with the concurrent formation of a TFSI network. These solvation environments computed from the FPMD simulations were compared with the solvation environments for the same system size calculated from simulations using two molecular mechanics force fields (FF), and a good agreement between the results was obtained.
Furthermore, to probe the dynamics of the system, diffusion coefficients of the species and the van Hove functions (from FF-based simulations) for the Li-water and Li-TFSI interactions are computed. Lithium diffusion coefficients at varying salt concentrations are compared with the experimental results. The structure decorrelation timescales obtained from van Hove functions are compared with the diffusion timescales to understand the lithium transport mechanism through the electrolyte. These insights into the structure and dynamics of the aqueous LiTFSI systems provide an opportunity to design electrolytes for Li-ion batteries with enhanced performance and safety.