Additive for non-aqueous liquid electrolyte, non-aqueous liquid electrolyte and lithium secondary cell comprising the same

摘要

An additive for a non-aqueous liquid electrolyte is provided to improve high temperature cycle characteristics and low temperature output of a lithium secondary battery by forming a solid electrolyte interface at a negative electrode and to prevent the degradation of the surface of a positive electrode in high temperature cycle and the oxidation reaction of electrolyte. An additive for a non-aqueous liquid electrolyte comprises any one nitrile group-cotaining compound selected from the group consisting of succinonitrile and dicyanobutene or their mixture, or lithium oxalyl difluoro borate. The content of the lithium oxalyl difluoro borate is 100-500 parts by weight based on the nitrile group-cotaining compound.