Enhanced Electrode Composition for Li ion Battery
Carbon nanotube-based compositions and methods of making an electrode for a Li ion battery are disclosed. It is an objective of the instant invention to disclose a composition for preparing an electrode of a lithium ion battery with incorporation of carbon nanotubes with more active material by having less conductive filler loading and less binder loading such that battery performance is enhanced.
1 . An electrode material composition for coating to a metallic current collector for a lithium battery comprising;
multi-walled carbon nanotubes in an agglomerate;
electrode active materials chosen from a group consisting of lithium, oxygen, phosphorous, sulphur, nitrogen, nickel, cobalt, manganese, vanadium, silicon, carbon, graphite, aluminum, niobium, titanium and zirconium and iron;
a dispersant chosen from a group consisting of poly(vinylpyrrolidone) (PVP), poly(styrene sulfonate) (PSS), poly(phenylacetylene) (PAA), poly(meta-phenylenevinylene) (PmPV), polypyrrole (PPy), poly(p-phenylene benzobisoxazole) (PBO), natural polymers, amphiphilic materials in aqueous solutions, anionic aliphatic surfactant, sodium dodecyl sulfate (SDS), cyclic lipopeptide bio surfactant, surfactin, water-soluble polymers, carboxyl methyl cellulose, hydroxyl ethyl cellulose, poly(vinyl alcohol), PVA, sodium dodecyl sulfate, SDS, n-methylpyrrolidone, polyoxyethylene surfactant, poly(vinylidene fluoride), PVdF, carboxyl methyl cellulose (CMC), hydroxyl ethyl cellulose (HEC), polyacrylic acid (PAA), polyvinyl chloride (PVC) and combinations thereof; and
a polymeric binder chosen from a group consisting of polyethylene, polypropylene, polyamide, polyurethane, polyvinyl chloride, polyvinylidene fluoride, thermoplastic polyester resins and mixtures thereof and is less than about 0.5% to about 5% by weight of the electrode material composition wherein the electrode active material is about 30-60% by weight, the carbon nanotubes are present in a range from about 0.2 to about 5% by weight, and the dispersant is less than about 0.1 to 2% by weight before coating to a metallic current collector.
2 . The electrode material composition of claim 1 wherein the carbon nanotube agglomerates are made in a fluidized bed reactor.
3 . The electrode material composition of claim 2 , wherein the carbon nanotube agglomerates have a maximum dimension from about 0.5 to about 1000 microns.
4 . The electrode material composition of claim 2 , wherein the carbon nanotubes have a diameter from about 4 to about 100 nm.
5 . The electrode material composition of claim 1 wherein the tap density of the carbon nanotube agglomerates is greater than about 0.02 g/cm 3 .
6 . The electrode material composition of claim 1 wherein the bulk resistivity of coating is less than 10 ohm-cm.
7 . A method of preparing an electrode material using the electrode material composition of claim 1 comprising the steps:
forming a paste composition comprising carbon nanotube agglomerates, dispersant and polymeric binders;
mixing the paste composition with a lithium ion battery active material composition wherein the paste composition is in a range from about 1% to about 25.0% by weight of the mixed composition;
coating the mixed paste composition and active material composition onto a metal conductor; and
removing excess volatile components to form an electrode for a lithium ion battery such that after removal of the excess volatile components the active material composition is more than about 80% by weight of the coated paste and battery material composition.
8 . The method of claim 6 wherein the active material composition is more than about 90% by weight of the coated paste and battery material composition after removal of the excess volatile components.
9 . The method of claim 6 further comprising the step of mixing a polymeric binder with a liquid vehicle before mixing the paste composition with lithium ion battery materials.
10 . The method of claim 8 wherein the polymeric binder is chosen from a group consisting of polyethylene, polypropylene, polyamide, polyurethane, polyvinyl chloride, polyvinylidene fluoride, thermoplastic polyester resins, and mixtures thereof and is less than about 5% by weight of the paste composition.
11 . The method of claim 6 wherein the lithium ion battery electrode active materials are chosen from a group consisting of lithium, oxygen, phosphorous, sulphur, nitrogen, nickel, cobalt, manganese, vanadium, silicon, carbon, graphite, aluminum, niobium, titanium, and zirconium and iron.
12 . The method of claim 6 wherein the multi-walled carbon nanotube agglomerates, dispersant and polymeric binders are formed into a dry pellet prior to mixing with the lithium ion battery active material composition.