A new class of electrochemically and thermally stable lithium salts for lithium battery electrolytes .2. Conductivity of lithium organoborates in dimethoxyethane and propylene carbonate

A conductivity study is carried out on Lithium bis[1,2 benzenediolato (2-)-O,O']borate and on Lithium bis[3-fluoro-1,2-benzenediolato(2-)-O,O']borate in dimethoxyethane and propylene carbonate from infinite dilution to saturation in the temperature range 228<T (K) <308. The electron-drawing fluorine substituent produces a decrease of the association constant by a factor of about three for PC-based solutions and 5.5 for solutions in dimethoyxyethane. The increase in the maximum of conductivity by about 30% (propylene carbonate) and about 80% (dimethoxyethane), independent of temperature, reveals the effect of ion-ion interaction on the conductivity maximum, with the solvent permittivity, viscosity, and ionic radii remaining unchanged. Synthesis, analysis, and purification of Lithium bis[3-fluoro-1,2-benzenediolato(2-)O,O']borate, which is a candidate for lithium batteries, is described.