CONICET | Buscador de Institutos y Recursos Humanos

We present molecular dynamics simulation results pertaining to the solvation of Li+ in dimethylsulfoxide-acetonitrile binary mixtures. The results are potentially relevant in the design of Li-airbatteries that rely on aprotic mixtures as solvent media. To analyze effects derived from differences inionic size and charge sign, the solvation of Li+ is compared to the ones observed for infinitely dilutedK+ and Cl− species, in similar solutions. At all compositions, the cations are preferentially solvatedby dimethyl sulfoxide. Contrasting, the first solvation shell of Cl− shows a gradual modification in itscomposition, which varies linearly with the global concentrations of the two solvents in the mixtures.Moreover, the energetics of the solvation, described in terms of the corresponding solute-solventcoupling, presents a clear non-ideal concentration dependence. Similar nonlinear trends were foundfor the stabilization of different ionic species in solution, compared to the ones exhibited by theirelectrically neutral counterparts. These tendencies account for the characteristics of the free energyassociated to the stabilization of Li+Cl−, contact-ion-pairs in these solutions. Ionic transport is alsoanalyzed. Dynamical results show concentration trends similar to those recently obtained from directexperimental measurements.