Efficient Dry Process for Superior Electrodes

A method of making an electrode for an electrochemical cell includes the step of providing an electrode composite comprising from 70 – 98 % active material , from 0 – 10 % conductive material additives , and from 2 – 20 % polymer binder , based on the total weight of the electrode composite . The electrode composite is mixed and then compressed the electrode composite into an electrode composite sheet . The electrode composite sheet is applied to a current collector with pressure to form an electrode , wherein the electrode possesses positive characteristics for adhesion according to ASTM standard test D3359 – 09e2 , entitled Standard Test Methods for Measuring Adhesion by Tape Test , and wherein the electrode composite sheet and the electrode possess positive characteristics for flexibility according to the Mandrel Test . The binder can be a single nonfluoropolymer binder . Dry process electrodes are also disclosed .

We claim : 1 . A method of making an electrode for an electrochemi cal cell , comprising the steps of : providing an electrode composite comprising from 70 – 98 % active material , from 0 – 10 % conductive mate rial additives , and from 2 – 20 % polymer binder , based on the total weight of the electrode composite ; mixing the electrode composite ; compressing the electrode composite into an electrode composite sheet ; applying the electrode composite sheet to a current col lector with pressure to form an electrode , wherein the electrode possesses positive characteristics for adhe sion according to ASTM standard test D3359 – 09e2 , entitled Standard Test Methods for Measuring Adhe sion by Tape Test , and wherein the electrode composite sheet and the electrode possess positive characteristics for flexibility according to the Mandrel Test . 2 . The method of claim 1 , wherein the binder is a single nonfluoropolymer binder . 3 . The method of claim 1 , wherein the active material comprises at least 80 % by weight of the electrode compos ite . 4 . The method of claim 1 , wherein the active material is a positive electrode active material comprising at least one selected from the group consisting of LiCo02 , LiNi1 , 3Cou 3M11 / 302 , LiNio . 8C00 . 15Al2 . 05O2 , Lii + xNi1 / 3C01 / 3M11 / 302 , where 0 < x < 0 . 8 , LiMn204 , LiFePO4 , LizMn204 , LiNi CoA102 , LiNi , Co _ M _ O , where M = Mn , Al , Sn , In , Ga or Ti and 0 . 15 < x < 0 . 5 , 0 . 5 < y < 0 . 8 and ( < z < 0 . 15 , Li [ Li ( 1 – 2v ) / 3Ni „ Mn ( 2 – y ) / 3 ] O2 , Li [ Li ( 1 – x ) / 3 Co , . Mn ( 2 – 2y ) 3 ] 0 , and Li [ Ni , Coi 2yMn , 102 , 0 < y < 0 . 5 , LiNiC002 . MnO2 , lithium rich com pounds Li1 + y ( Ni1 / 3C01 / 3M11 / 3 ) 1 – 102 , where y = x / ( 2 + x ) and X = 0 – 0 . 33 , and xLi MnO3 ( 1 – x ) Li ( NiCoMn ) O2 and Li ( 1 + y ) ( Ni . . . Coo2Mno . 3 ) 1 – 102 , where y = x / ( 2 + x ) and x = 0 – 0 . 33 , and LIMPO4 , where M is at least one selected from the group consisting of V , Cr , Mn , Fe , Co , and Ni . 5 . The method of claim 1 , wherein the active material is an anode active material comprising at least one selected from the group consisting of carbon , hard carbon , soft carbon , synthetic graphite , natural graphite , mesophase car bon microbeads , SnO2 , SnO , TiO2 , Li Tis012 , LiTi204 , SiO , and silicon . 6 . The method of claim 1 , wherein the conductive material additive comprises at least one selected from the group consisting of carbon black , acetylene black , carbon nano tube , carbon nanofiber , carbon fibers , coke , high surface area carbon , graphite , metal particles , and conducting polymer . 7 . The method of claim 1 , wherein the binder material is a soft polymer comprising at least one selected from the group consisting of acrylic – based soft polymers , isobuty lene – based soft polymers , diene – based soft polymers , sili con – containing soft polymers , olefin – based soft polymers , vinyl – based soft polymers , epoxy – based soft polymers , fluo rine – containing soft polymers , natural rubbers , polypeptides , proteins , polyester – based thermoplastic elastomers , vinyl chloride – based thermoplastic elastomers , and polyamide based thermoplastic elastomers . 8 . The method of claim 1 , wherein the binder material is a soft polymer comprising at least one selected from the group consisting of homopolymers or copolymers of acrylic acid or methacrylic acid derivatives , polybutyl acrylate , polybutyl methacrylate , polyhydroxyethyl methacrylate , polyacrylamide , polyacrylonitrile , butyl acrylate – styrene copolymers , butyl acrylate – acrylonitrile copolymers , butyl acrylate – acrylonitrile – glycidyl methacrylate copolymers , polyisobutylene , isobutylene – isoprene rubber , isobutylene styrene copolymers , polybutadiene , polyisoprene , butadi ene – styrene random copolymers , isoprene – styrene random copolymers , acrylonitrile – butadiene copolymers , acryloni trile – butadiene – styrene copolymers , butadiene – styrene block copolymers , styrene – butadiene – styrene – block copoly mers , isoprene – styrene – block copolymers , styrene – isoprene styrene – block copolymers , dimethylpolysiloxane , diphenylpolysiloxane , dihydroxypolysiloxane , liquid poly ethylene , polypropylene , poly – 1 – butene , ethylene – a – olefin copolymers , propylene – a – olefin copolymers , ethylene – pro pylene – diene copolymers ( EPDM ) , ethylene – propylene – sty rene copolymers , polyvinyl alcohol , polyvinyl acetate , poly vinyl stearate , vinyl acetate – styrene copolymers , polyethylene oxide , polypropylene oxide , epichlorohydrin rubbers , vinylidene fluoride – based rubbers , tetrafluoroethyl ene – propylene rubbers , poly ( 2 – methoxyethoxyethoxyethyl ene ) , styrene butadiene rubber ( SBR ) , butadiene – acryloni trile , rubber ( NBR ) , hydrogenated NBR ( HNBR ) , epichlorhydrin rubber ( CHR ) and acrylate rubber ( ACM ) . 9 . The method of claim 1 , wherein the binder material comprises asoft polymer comprising at least one selected from the group consisting of soft polymers having a cross linked structure , and soft polymers having a functional group in the range of about 3 – 12 % by weight of the soft polymer , wherein the functional group is at least one selected from the group consisting of an unsaturated group , a carboxyl group , a hydroxy group , an amino group , and an epoxy group 10 . The method of claim 1 , wherein the mixing step comprises at least one selected from the group consisting of rubber kneading , two roll milling , tumbling mixing , air jet mixing , mixture grinding , high – shear mixing , V – blender mixing , mixing by a screw – driven mass mixer , double – cone mixing , drum mixing , conical mixing , two – dimensional mixing , double Z – arm blending , ball – milling , and fluidized bed blending 11 . The method of claim 1 , wherein the mixing step further comprises the step of providing a solvent and mixing the solvent with the binder at a binder to solvent ratio of from 100 : 1 to 1 : 100 by weight , and adding the active material particles and carbonaceous conductors to binder solution in a ratio of from 10 : 1 to 1 : 5 , by weight . 12 . The method of claim 11 , wherein the solvent com prises at least one selected from the group consisting of a hydrocarbon , ketone , naphtha , acetate , acrylonitrile , toluene , xylene , alcohol , or esters . 13 . The method of claim 1 , wherein said electrode com posite sheet has a thickness of less than 200 microns . 14 . The method of claim 1 , wherein said electrode com posite sheet has a thickness of from 50 – 150 microns . 15 . The method of claim 1 , wherein the electrode com posite sheet comprises less than 50 % solvent , by weight of the electrode composite sheet . 16 . The method of claim 1 , wherein the binder material comprises at least two binder materials . 17 . The method of claim 1 , further comprising the step of forming a binder coating of a Li ion transporting material on the surface of the active materials . 18 . The method of claim 17 , wherein the binder materials comprise at least one selected from the group consisting of homopolymers and copolymers of polyvinylidenefluoride ( PVDF ) , polyolefinic materials with electron withdrawing substituents , and water soluble binders . 19 . The method of claim 17 , wherein the binders comprise at least one selected from the group consisting of copoly mers of vinylidene fluoride and hexafluoropropylene , poly ( methyl methacrylate ) ( PMMA ) , polyacrylic acids , poly acrylronitrile ( PAN ) , polyvinyl chloride ( PVC ) , poly vinylalcohols ( PVA ) , polyvinyl pyrrolidone , polyethylene oxides ( PEO ) , polyethylene glycols , polyacrylamide ( PAAm ) , poly – N – isopropylearylamide , poly – N , N – dimethyl acrylamide , polyethyleneimine , polyoxyethylene , polyvi nylsulfonic acid , polyactic acid ( PLA ) , polyacrylic acid ( PAA ) , polysuccinic acid , poly maleic acid and anhydride , poly furoic ( pyromucic acid ) , poly fumaric acid , poly sorbic acid , poly linoleic acid , poly linolenic acid , poly glutamic acid , poly methacrylic acid , poly licanic acid , poly glycolic acid , polyaspartic acid , poly amic acid , poly formic acid , poly acetic acid , poly propionic acid , poly butyric acid , poly sebacic acid , acrylic acid – type water – soluble polymers , maleicanhydride – type water – soluble polymers , poly ( N – vinyl amides ) , polyacrylamides , N – methylacrylamide , N – ethyl acrylamide , N , N – dimethyl acrylamide , and N , Ndiethylacry lamide , poly ( hydroxy – ethyl methacrylate ) , polyesters , poly ( ethyl oxazolines ) , poly ( oxymethylene ) , poly ( vinyl methyl ether ) , poly ( styrene sulfonic acid ) , poly ( ethylenesulfonic acid ) , poly ( vinyl phosphoric ) acid , poly ( maleic acid ) , starch , cellulose , protein , polysaccharide , dextrans , tannin , lignin , polyethylene – polypropylene copolymer , copolymers of poly ( acrylonitrile – co – acrylamide ) , co – polymer of polystyreneb utadiene rubber and poly ( acrylonitrile – co – acrylamide ) , or mixtures or co – polymers thereof , carboxymethyl cellulose ( CMC ) , poly vinylalcohols ( PVA ) , polyacrylic acids ( PAA ) , polystyrenebutadiene rubber ( SBR ) , PEO , or co – polymers of polyacrylonitrile , polyethylene oxides ( PEO ) and polyacry lamide ( PAAm ) , poly vinylalcohols ( PVA ) and polyacryl amide ( PAAm ) , or PEO and polyacrylronitrile ( PAN ) , or co – polymers or mixtures thereof . 20 . The method of claim 17 , wherein the second binder material is a soft polymer comprising at least one selected from the group consisting of homopolymers or copolymers of acrylic acid or methacrylic acid derivatives , polybutyl acrylate , polybutyl methacrylate , polyhydroxyethyl meth acrylate , polyacrylamide , polyacrylonitrile , butyl acrylate styrene copolymers , butyl acrylate – acrylonitrile copolymers , butyl acrylate – acrylonitrile – glycidyl methacrylate copoly mers , polyisobutylene , isobutylene – isoprene rubber , isobu tylene – styrene copolymers , polybutadiene , polyisoprene , butadiene – styrene random copolymers , isoprene – styrene random copolymers , acrylonitrile – butadiene copolymers , acrylonitrile – butadiene – styrene copolymers , butadiene – sty rene – block copolymers , styrene – butadiene – styrene – block copolymers , isoprene – styrene – block copolymers , styrene isoprene – styrene – block copolymers , dimethylpolysiloxane , diphenylpolysiloxane , dihydroxypolysiloxane , liquid poly ethylene , polypropylene , poly – 1 – butene , ethylene – a – olefin copolymers , propylene – d – olefin copolymers , ethylene – pro pylene – diene copolymers ( EPDM ) , ethylene – propylene – sty rene copolymers , polyvinyl alcohol , polyvinyl acetate , poly vinyl stearate , vinyl acetate – styrene copolymers , polyethylene oxide , polypropylene oxide , epichlorohydrin rubbers , vinylidene fluoride – based rubbers , tetrafluoroethyl ene – propylene rubbers , poly ( 2 – methoxyethoxyethoxyethyl ene ) , styrene butadiene rubber ( SBR ) , butadiene – acryloni trile , rubber ( NBR ) , hydrogenated NBR ( HNBR ) , epichlorhydrin rubber ( CHR ) and acrylate rubber ( ACM ) . 21 . The method of claim 1 , wherein the compressing step comprises passing the electrode composite through a pair of opposing rollers . 22 . The method of claim 21 , wherein the electrode com posite sheet is passed through a plurality of pairs of rollers , the spacing between the rollers decreasing for each subse quent pair of rollers . 23 . A binder system for the fabrication of an electrode comprising active materials and a current collector , the binder comprising : a first lithium ion transporting polymeric coating binder material coating the active materials to produce a first binder coated active material composite ; and , a second polymeric binder material binding the coated first binder coated active material composites together and to the current collector ; wherein when formed the electrode possesses positive characteristics for adhesion according to ASTM stan dard test D3359 – 09e2 , entitled Standard Test Methods for Measuring Adhesion by Tape Test , and wherein the electrode composite sheet and the electrode possess positive characteristics for flexibility according to the Mandrel Test . 24 . The binder of claim 23 , wherein the ratio of the first polymeric coating binder material to the second polymeric binder material is between 1 : 20 and 20 : 1 by weight . 25 . An electrode , comprising : electrode active materials ; a first lithium ion transporting polymeric binder material for coating the active materials to produce a first binder coated active material composite ; a second polymeric binder material binding the first binder coated active material composites together and to the current collector ; wherein when formed the electrode possesses positive characteristics for adhesion according to ASTM stan dard test D3359 – 09e2 , entitled Standard Test Methods for Measuring Adhesion by Tape Test , and wherein the electrode composite sheet and the electrode possess positive characteristics for flexibility according to the Mandrel Test . 26 . An electrode , comprising : a current collector ; an electrode composite comprising from 70 – 98 % active material , from 0 – 10 % conductive material additives , and from 2 – 20 % polymer binder , based on the total weight of the electrode composite ; the electrode composite being formed into an electrode composite sheet ; the electrode composite sheet being adhered to the current collector to form the electrode , wherein the electrode possesses positive characteristics for adhesion accord ing to ASTM standard test D3359 – 09e2 , entitled Stan dard Test Methods for Measuring Adhesion by Tape Test , and wherein the electrode composite sheet and the electrode possess positive characteristics for flexibility according to the Mandrel Test . 27 . The electrode of claim 26 , wherein the polymer binder is a single nonfluoropolymer binder . 28 . A process for making an electrode , comprising the steps of : coating electrode active materials with a first lithium ion transporting polymeric coating binder material to pro duce a first binder coated active material composite ; mixing the coated electrode active materials with a second polymeric binder material for binding the first binder coated active material composite together and to a current collector ; compressing the electrode composite into an electrode composite sheet ; and , applying the electrode composite sheet to a current col lector with pressure to form an electrode , wherein the electrode possesses positive characteristics for adhe sion according to ASTM standard test D3359 – 09e2 , entitled Standard Test Methods for Measuring Adhe sion by Tape Test , and wherein the electrode composite sheet and the electrode possess positive characteristics for flexibility according to the Mandrel Test .