Electrolyte system for lithium batteries, the use thereof, and method for enhancing the safety of lithium batteries

摘要

Electrolyte systems for lithium batteries with enhanced safety containing at least one lithium-containing conductive salt and at least one electrolyte liquid, in which the electrolyte liquid includes an effective amount of at least one partially fluorinated amide of formula (I)R1CO-NR2R3 (I)in which R1 is a linear C1-C6 alkyl group, in which one or more hydrogen atoms are replaced by fluorine atoms; or a branched C3-C6 alkyl group in which one or more hydrogen atoms are replaced by fluorine atoms; or a C3-C7 cycloalkyl group optionally substituted one or more times by a linear C1-C6 alkyl group and/or branched C3-C6 alkyl group, in which one or more hydrogen atoms of the cycloalkyl radical and/or of the optional linear and/or branched alkyl substituents are replaced by fluorine atoms; and R2 and R3 independently represent an identical or different linear C1-C6 alkyl group, a branched C3-C6 alkyl group or a C3-C7 cycloalkyl group, or R2 and R3 together with the amide nitrogen form a saturated five or six-member nitrogen-containing ring, or are joined with one or more additional N and/or O atom(s) to form a 4 to 7-member ring, in which the additional N atoms present in the ring are optionally saturated with C1-C3 alkyl groups and the ring carbons may also carry C1-C3 alkyl groups.