A partial-molar volume study of electrolytes in propylene carbonate-based lithium battery electrolyte solutions at 298.15 K

Abstract

Apparent molar volumes (V2, ϕ ) and standard partial-molar volumes (V20, ϕ ) of LiClO4 and LiBr at 298.15 K have been determined from precise density measurements in solvent mixtures of propylene carbonate (PC) with dimethylformamide (DMF), tetrahydrofuran (THF), acetonitrile (AN), and methyl formate (MF). The scaled particle theory is used to calculate the contributions of the cavity formation and the electrolyte-solvent interactions to the standard partial-molar volumes. It is shown that V20, ϕ is strongly dependent on the nature of the solvents, and the trends in V20, ϕ with composition of the solvent mixtures are determined by the interaction volumes of electrolytes with solvents. The results are discussed in terms of ionic preferential solvation, packing effect of solvents in the solvation shell, and electrostriction of solvents by ion.Key words: partial-molar volume, scaled particle theory, lithium salts, propylene carbonate, solvent mixtures, lithium battery electrolytes.