Electrolytes based on sulfone mixtures for lithium and lithium-ion batteries: the low-temperature properties.

The physicochemical properties and the phase state of sulfolane (1)—ethyl isobutyl sulfone (2) mixtures and 1 M LiClO4 solutions based on these mixtures were studied in the temperature range from 50 to −70 °C. The mixtures form an eutectic with a temperature of −31.2 °C. The phase diagram of the binary system 1–2 exhibits two solidus lines owing to the ability of sulfolane to exist in three phase states (crystalline, mesomorphic, and liquid). Solutions of LiClO4 in the mixtures of sulfones 1 and 2 containing more than 15 mol.% of 2 are in the liquid state down to −70 °C. The specific conductivity and viscosity isotherms of the 1 M LiClO4 solutions in the mixtures of sulfones 1 and 2, depending on the composition of the electrolyte solvent, are nonlinear, namely, specific conductivity is lower while the viscosity is higher than the corresponding additive values. The maximum degree of electrolytic dissociation of LiClO4 is achieved in the sulfone mixtures containing about 15% mol. of sulfone 2. Electrolyte solutions based on the mixtures of sulfones 1 and 2 containing more than 15 mol.% of 2 can be used as electrolytes for low-temperature lithium-ion and post-lithium-ion batteries. [ABSTRACT FROM AUTHOR]