LITHIUM SULFUR SECONDARY BATTERY

摘要

PURPOSE: A lithium sulfur secondary battery is provided to improve the lifetime and the capacitance by enhancing the conductivity of an anode plate by employing a polymer film coating the active material of an anode. CONSTITUTION: The lithium sulfur secondary battery comprises an anode employing an active material selected from the group consisting of sulfur(S8), lithium sulfide and lithium polysulfide; a cathode employing a lithium metal or a lithium alloy; and a polymer film which is ion-conductive and electrically conductive and coats the cathode active material. Preferably the polymer film contains further carbon or metal powder and has a thickness of 20 micrometers or less. The polymer film is selected from the group consisting of polyvinylidene fluoride, a copolymer of polyvinylidene fluoride and hexafluorophosphate, poly(methyl methacrylate), poly(vinyl acetate), poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate), poly(methyl methacrylate-co-ethyl acrylate), polyacrylonitrile, poly(ethylene oxide), a copolymer of poly(vinyl chloride) and vinyl acetate, poly(vinyl alcohol), poly(1-vinyl pyrrolidone-co-vinyl acetate), cellulose acetate and poly(vinyl pyrrolidone).