New organic borate compounds and the nonaqueous electrolytes and lithium secondary batteries using the compounds

Abstract

The object of the present invention is to supply organic borates highly soluble even in a solvent of a low dielectric constant; nonaqueous electrolytes made from these organic borates and excellent in characteristics; lithium secondary batteries with improved high-temperature storage characteristics; electric appliances that can be free of protection circuits, and; various applications of the electric appliances. The present invention relates to: organic borate compounds represented by structural formula (1) where X denotes lithium or quaternary ammonium or quaternary phosphonium and R1, R2, R3, and R4 each denote an independent halogen-atom displacement alkyl group whose carbon number ranges from 1 to 4, and organic borate compounds whose R1, R2, R3, and R4 are represented by trifluoromethyl groups or pentafluoroethyl groups, in particular, can be easily dissolved to concentrations of at least 0.8 mol/dm−3 in solvent mixtures heavily laden with a fluorinated solvent and offer a maximum electroconductivity value at a low concentration of 0.4 mol/dm−3; lithium secondary batteries using the lithium borates pertaining to the invention; nonaqueous electrolytes that minimize decreases in the high-temperature recovery capacities of these lithium secondary batteries; electric appliances that can be free of protection circuits, and; various applications of the electric appliances.

Dependencies are inferred from the claim text.