Quantum chemistry study of the oxidation-induced stability and decomposition of propylene carbonate-containing complexes.

Oxidation-induced decomposition reactions of the representative complexes of propylene carbonate (PC)-based electrolytes were investigated using density functional theory (DFT) and a composite G4MP2 method. The cluster-continuum approach was used, where the oxidized PCn cluster was surrounded by the implicit solvent modeled via a polarized continuum model (PCM). The oxidative stability of the PCn (n = 2, 3, and 4) complexes was found to be around 5.4-5.5 V vs. Li(+)/Li, which is not only lower than the stability of an isolated PC but also lower than the stability of the PC-PF6(-), PC-BF4(-) or PC-ClO4(-) complexes surrounded by the implicit solvent. The oxidation-induced decomposition reactions were studied. The decomposition products of the oxidized PC2 contained CO2, acetone, propanal, propene, and carboxylic acid in agreement with the previous experimental studies.