Electrolyte solvents for high voltage lithium ion batteries: ion correlation and specific anion effects in adiponitrile.

We studied dynamic and structural properties of two lithium conducting salts in the aprotic organic solvent adiponitrile by a combination of atomistic molecular dynamics (MD) simulations, quantum chemical calculations, and experimental findings. The outcomes of our simulations reveal significant differences between both lithium salts, namely lithium tetrafluoroborate (LiBF4) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) at various concentrations, which can be mainly attributed to the solvation behavior of the individual anions. The increased tendency of ion complex formation for LiBF4 is reflected by lower values regarding the measured and computed effective ionic conductivities when compared to LiTFSI.