Physical and Electrolytic Properties of Difluorinated 3-Methyl-2-oxazolidinones and Their Application to Lithium Rechargeable Batteries

Difluorination of 3-methyl-2-oxazolidinone (3Me2Ox or NMO (N-methyloxazolidinone)) decreased the relative permittivity and the ionic conductivity and increased the dynamic viscosity and the anodic stability. The difluorinated NMOs (DFNMOmix) consisted of a mixture of 4,4′-difluoro-3-methyl-2-oxazolidinone (4,4′-DFNMO) and 4,5-difluoro-3-methyl-2-oxazolidinone (4,5-DFNMO), and its molar ratio was 3:7. The addition of DFNMOmix to an ethylene carbonate (EC)-diethyl carbonate (DEC) equimolar binary mixture suppressed discharge capacity fading in a Li/LiCoO2 coin cell.