Mobility and Ionic Association of Lithium Salts in a Propylene Carbonate‐Ethyl Methyl Carbonate Mixed Solvent

Electrolytic conductivities of lithium salts have been measured in equimolar mixtures of propylene carbonate and either ethyl methyl carbonate or 1,2‐dimethoxyethane at 25°C over a salt concentration range of 10 −2 to 10 −3 mol dm −3 . The limiting molar conductivities and association constants were calculated from the expanded Fuoss‐Hsia equation. The Walden product of lithium ion was not enhanced by the addition of ethyl methyl carbonate as observed in the case of 1,2‐dimethoxyethane, due to the lack of specific solvation. LiPF 6 and Li ( CF 3 SO 2 ) 2 N in the propylene carbonate‐ethyl methyl carbonate mixed solvent formed solvent‐separated ion pairs, which resulted in decreased ion association.