New lithium salts in electrolytes for lithium-ion batteries (Review)

The properties of electrolyte systems based on standard nonaqueous solvent composed of a mixture of dialkyl and alkylene carbonates and new commercially available lithium salts potentially capable of being an alternative to thermally unstable and chemically active lithium hexafluorophosphate LiPF6 in the mass production of lithium-ion rechargeable batteries are surveyed. The advantages and drawbacks of electrolytes containing lithium salts alternative to LiPF6 are discussed. The real prospects of substitution for LiPF6 in electrolyte solutions aimed at improving the functional characteristics of lithium-ion batteries are assessed. Special attention is drawn to the efficient use of new lithium salts in the cells with electrodes based on materials predominantly used in the current mass production of lithium-ion batteries: grafitic carbon (negative electrode), LiCoO2, LiMn2O4, LiFePO4, and also solid solutions isostructural to lithium cobaltate with the general composition LiMO2 (M = Co, Mn, Ni, Al) (positive electrode).