Stable high-voltage electrolyte for lithium secondary battery

摘要

An organic electrolyte for use in a lithium secondary battery comprising a lithium salt dissolved in an organic solvent mixture is disclosed. The lithium salt can be LiClO4, LiPF6, LiBF4, LiCF3SO3, LiAsF6, or other lithium salt, and the organic solvent mixture contains a carbonate and an acetate. The carbonate is ethylene carbonate, and the acetate can be either methyl acetate or ethyl acetate. The carbonate and the acetate are provided in a ratio of carbonate/acetate ranging from 80/20 to 20/80, or preferably from 40/60 to 60/40, and said lithium salt has a concentration of between 0.6 and 1.5M, or preferably at about 1M. The electrolyte exhibits excellent stability in a lithium secondary battery having a cathode which contains either LiCoO2 or LiMn2O4, and can withstand charge/discharge voltages of at least as high as 5 V (vs. Li/Li+), with excellent service life.