Positive active material and positive active material composition for lithium-sulfur battery and method of preparing positive active material composition
AssigneeSamsung SDI Co., Ltd.
InventorsJea-Woan Lee, Seung-Hee Park
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Abstract
The present invention relates to a positive active material for a lithium-sulfur battery and a method of preparing a positive active material composition comprising the same, and the positive active material includes a sulfur compound, a conductive agent adhered to the sulfur compound, and a binder including at least one polymer, which is positioned between the sulfur compound and the conductive agent to bind the conductive agent to the sulfur compound. The capacity per active mass weight of the positive active material increases by 25 to 35%, and the positive active material has improved discharge potentials and discharge capacity at high rate.
Claims16
A positive electrode for a lithium-sulfur battery comprising:
- a current collector;
- and
- a positive active material comprising:
- a sulfur compound;
- a conductive agent adhered to said sulfur compound;
- and
- a binder comprising first and second binders and at least one polymer included in at least one of the first and second binders, where one of the first and second binders binds said conductive agent to said sulfur compound and the other one of the first and second binders is usable to bind the positive active material to the current collector for the lithium-sulfur battery, wherein said at least one polymer is selected from the group consisting of polyvinylidene fluoride, a copolymer of polyvinylidene fluoride and polyhexafluoropropylene, poly(vinylacetate), poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate), poly(methylmethacrylate-co-ethyl acrylate), polyacrylonitrile, polyvinyl chloride-co-vinyl acetate, polyvinyl alcohol, poly(1-vinylpyrrolidone-co-vinyl acetate), cellulose acetate, polyvinylpyrrolidone, polyacrylate, polymethacrylate, polyolefin, polyurethane, polyvinyl ether, acrylonitrile-butadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene-styrene, and sulfonated styrene/ethylene-butadiene/styrene triblock polymer.
A positive active material composition for a lithium-sulfur battery, comprising:
- a positive active material comprising a sulfur compound;
- a conductive agent adhered to the sulfur compound;
- a first binder comprising at least one polymer and that binds said conductive agent to the sulfur compound;
- a second binder usable to adhere said positive active material to a current collector;
- and
- an organic solvent, wherein said first binder is polyethylene oxide or polyvinyl acetate, and said second binder is polyvinyl pyrrolidone.
A lithium-sulfur battery, comprising:
- a positive electrode comprising a positive active material, the positive active material comprising a sulfur compound, a conductive agent, and a binder which binds the conductive agent to the sulfur compound;
- a negative electrode comprising a negative active material;
- and
- an electrolyte disposed between said positive and negative electrodes,
- wherein the positive active material is made by:
- mixing the sulfur compound, the conductive agent, and the binder in a first solvent;
- and
- drying the mixture to prepare the positive active material and, wherein said binder is two or more polymers selected from the group consisting of polyethylene oxide, polyvinylidene fluoride, a copolymer of polyvinylidene fluoride and polyhexafluoropropylene, poly(vinylacetate), poly(vinyl butyral-co-vinylalcohol-co-vinyl acetate), poly(methylmethacrylate-co-ethyl acrylate), polyacrylonitrile, polyvinylchloride-co-vinyl acetate, polyvinyl alcohol, poly(1-vinylpyrrolidone-co-vinyl acetate), cellulose acetate, polyvinylpyrrolidone, polyacrylate, polymethacrylate, polyolefin, polyurethane, polyvinyl ether, acrylonitrile-butadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene-styrene, or sulfonated styrene/ethylene-butadiene/styrene triblock polymer.
A positive active material composition for a lithium-sulfur battery, comprising:
- a positive active material comprising a sulfur compound;
- a conductive agent;
- and
- a binder,
- wherein said binder is two or more polymers selected from the group consisting of polyethylene oxide, polyvinylidene fluoride, a copolymer of polyvinylidene fluoride and polyhexafluoropropylene, poly(vinylacetate), poly(vinyl butyral-co-vinylalcohol-co-vinyl acetate), poly(methylmethacrylate-co-ethyl acrylate), polyacrylonitrile, polyvinylchloride-co-vinyl acetate, polyvinyl alcohol, poly(1-vinylpyrrolidone-co-vinyl acetate), cellulose acetate, polyvinylpyrrolidone, polyacrylate, polymethacrylate, polyolefin, polyurethane, polyvinyl ether, acrylonitrile-butadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene-styrene, or sulfonated styrene/ethylene-butadiene/styrene triblock polymer.
Dependencies are inferred from the claim text.