Quantum Chemistry Studies of the Oxidative Stability of Carbonate, Sulfone and Sulfonate-Based Electrolytes Doped with BF4 -, PF6 - Anions

Abstract

Quantum chemistry studies of the oxidative stability of carbonate, sulfonate and sulfone-based solvents with and without BF4-, PF6- anions were performed using M05-2X Minnesota density functional and cc-pvTz basis set. Presence of BF4- and PF6- anions was found to significantly decrease oxidative stability of a number of carbonate solvents such as ethylene carbonate, dimethyl carbonate and propylene carbonate via HF formation. Oxidation of the tetramethyl sulfone/BF4- and propargyl methanesulfonate/PF6- complexes resulted in the fluorine transfer to the solvent. Oxidation of the tetramethyl sulfone/BF4- complex also resulted in a spontaneous ring opening. No water was needed to form PF5 and BF3 upon oxidation of the solvent/BF4- and solvent/PF6- complexes. Density functional estimates of the solvent/anion oxidative stability were found in good agreement with available experimental data for non-active electrodes after polarized continuum model was utilized to implicitly account for the surrounding solvent dielectric permittivity.