Patent ID: 6535373
Filing Date: 2003-03-18
Classification: H01G,H01M,Y02E

Abstract:
In a non-aqueous electrolyte for an electrical storage device the improvement which comprises that said electrolyte contains a nitrile solvent and the combination of an imidazolium salt of the formula: Wherein R, R2, R3, R4, and R5 are alkyl groups having 1-3 carbon atoms and X is a member of the group consisting of tetrafluoroborate, triflate, and hexafluorophosphate hexafluoroarsenate and at least two tetraalkylammonium salts in a nitrile solvent in a combined molar concentration of about 0.6 to 2.5M, a conductivity in the range of about 50 to 58 mS/cm at 20Â° C. and can be cooled to at least âˆ’40Â° C. without precipitation, said tetraalkylammonium salts comprising tetraethylammonium tetrafluoroborate and methyltriethylammonium tetrafluoroborate.