MULTI-LAYERED POLYMER ELECTROLYTE AND LITHIUM SECONDARY BATTERY CONTAINING THE ELECTROLYTE

摘要

PURPOSE: A multi-layered polymer electrolyte and a lithium secondary battery containing the electrolyte are provided, to improve the adhesive strength, the mechanical properties, the low and high temperature characteristics, the high rate discharge capacity, the lifetime, the capacity and the stability of a battery. CONSTITUTION: The electrolyte comprises a separation membrane layer, a gel polymer electrolyte layer, and an organic electrolyte solution which is prepared by dissolving a lithium salt into an organic solvent. The separation membrane layer is made of a polymer electrolyte, polypropylene, polyethylene, polyvinylidene fluoride or non-woven; the gel polymer electrolyte layer comprises 5-90 wt% of a polyacrylonitrile-based polymer, 5-80 wt% of a polyvinylidene fluoride-based polymer or a poly(methyl methacrylate)-based polymer, and 5-80 wt% of a poly(vinyl chloride)-based polymer or a polyvinylidene fluoride-based polymer, and is coated to the one or both sides of the separation membrane. Preferably the lithium salt is selected from the group consisting of LiPF6, LiClO4, LiAsF6, LiBF4, LiCF3SO3, Li(CF3SO2)2N and their mixtures; and the organic solvent is selected from the group consisting of ethylene carbonate, propylene carbonate, diethyl carbonate, dimethyl carbonate, ethylmethyl carbonate and their mixtures.