Quantum Chemistry Studies of the Oxidative Stability of Carbonate, Sulfone and Sulfonate-Based Electrolytes Doped with BF_4~-, PF_6~- Anions

摘要

Quantum chemistry studies of the oxidative stability of carbonate, sulfonate and sulfone-based solvents with and without BF_4~-, PF_6~-anions were performed using M05-2X Minnesota density functional and cc-pvTz basis set. Presence of BF_4~- and PF_6~- 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/BF_4~- and propargyl methanesulfonate/PF_6~- complexes resulted in the fluorine transfer to the solvent. Oxidation of the tetramethyl sulfone/BF_4~- complex also resulted in a spontaneous ring opening. No water was needed to form PF_5 and BF_3 upon oxidation of the solvent/BF_4~- and solvent/PF_6~- 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.