CN115881963A - Rheology modifier for lithium ion battery cathode, preparation method of rheology modifier and lithium ion battery cathode - Google Patents
Rheology modifier for lithium ion battery cathode, preparation method of rheology modifier and lithium ion battery cathode Download PDFInfo
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- CN115881963A CN115881963A CN202211531338.0A CN202211531338A CN115881963A CN 115881963 A CN115881963 A CN 115881963A CN 202211531338 A CN202211531338 A CN 202211531338A CN 115881963 A CN115881963 A CN 115881963A
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- rheology modifier
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- 239000006254 rheological additive Substances 0.000 title claims abstract description 41
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 33
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 33
- 238000002360 preparation method Methods 0.000 title claims abstract description 20
- 239000000178 monomer Substances 0.000 claims abstract description 67
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims abstract description 25
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 22
- 239000008367 deionised water Substances 0.000 claims abstract description 20
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 20
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 claims abstract description 18
- 238000004132 cross linking Methods 0.000 claims abstract description 14
- 239000003995 emulsifying agent Substances 0.000 claims abstract description 12
- 238000007720 emulsion polymerization reaction Methods 0.000 claims abstract description 10
- 239000003999 initiator Substances 0.000 claims abstract description 10
- 125000005907 alkyl ester group Chemical group 0.000 claims abstract description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 32
- 238000003756 stirring Methods 0.000 claims description 22
- 238000004945 emulsification Methods 0.000 claims description 20
- 239000000839 emulsion Substances 0.000 claims description 19
- 229910052757 nitrogen Inorganic materials 0.000 claims description 16
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 claims description 14
- BAPJBEWLBFYGME-UHFFFAOYSA-N Methyl acrylate Chemical compound COC(=O)C=C BAPJBEWLBFYGME-UHFFFAOYSA-N 0.000 claims description 12
- 239000006258 conductive agent Substances 0.000 claims description 10
- JIGUQPWFLRLWPJ-UHFFFAOYSA-N Ethyl acrylate Chemical compound CCOC(=O)C=C JIGUQPWFLRLWPJ-UHFFFAOYSA-N 0.000 claims description 9
- 238000000034 method Methods 0.000 claims description 9
- PNJWIWWMYCMZRO-UHFFFAOYSA-N pent‐4‐en‐2‐one Natural products CC(=O)CC=C PNJWIWWMYCMZRO-UHFFFAOYSA-N 0.000 claims description 9
- 238000004321 preservation Methods 0.000 claims description 8
- 239000004641 Diallyl-phthalate Substances 0.000 claims description 7
- 239000011230 binding agent Substances 0.000 claims description 7
- QUDWYFHPNIMBFC-UHFFFAOYSA-N bis(prop-2-enyl) benzene-1,2-dicarboxylate Chemical compound C=CCOC(=O)C1=CC=CC=C1C(=O)OCC=C QUDWYFHPNIMBFC-UHFFFAOYSA-N 0.000 claims description 7
- 150000001732 carboxylic acid derivatives Chemical class 0.000 claims description 7
- HVVWZTWDBSEWIH-UHFFFAOYSA-N [2-(hydroxymethyl)-3-prop-2-enoyloxy-2-(prop-2-enoyloxymethyl)propyl] prop-2-enoate Chemical compound C=CC(=O)OCC(CO)(COC(=O)C=C)COC(=O)C=C HVVWZTWDBSEWIH-UHFFFAOYSA-N 0.000 claims description 5
- GVGUFUZHNYFZLC-UHFFFAOYSA-N dodecyl benzenesulfonate;sodium Chemical compound [Na].CCCCCCCCCCCCOS(=O)(=O)C1=CC=CC=C1 GVGUFUZHNYFZLC-UHFFFAOYSA-N 0.000 claims description 5
- 239000007773 negative electrode material Substances 0.000 claims description 5
- 239000002994 raw material Substances 0.000 claims description 5
- 229940080264 sodium dodecylbenzenesulfonate Drugs 0.000 claims description 5
- LCPVQAHEFVXVKT-UHFFFAOYSA-N 2-(2,4-difluorophenoxy)pyridin-3-amine Chemical compound NC1=CC=CN=C1OC1=CC=C(F)C=C1F LCPVQAHEFVXVKT-UHFFFAOYSA-N 0.000 claims description 4
- DXPPIEDUBFUSEZ-UHFFFAOYSA-N 6-methylheptyl prop-2-enoate Chemical compound CC(C)CCCCCOC(=O)C=C DXPPIEDUBFUSEZ-UHFFFAOYSA-N 0.000 claims description 4
- DBMJMQXJHONAFJ-UHFFFAOYSA-M Sodium laurylsulphate Chemical compound [Na+].CCCCCCCCCCCCOS([O-])(=O)=O DBMJMQXJHONAFJ-UHFFFAOYSA-M 0.000 claims description 4
- DAKWPKUUDNSNPN-UHFFFAOYSA-N Trimethylolpropane triacrylate Chemical compound C=CC(=O)OCC(CC)(COC(=O)C=C)COC(=O)C=C DAKWPKUUDNSNPN-UHFFFAOYSA-N 0.000 claims description 4
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium peroxydisulfate Substances [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 claims description 4
- VAZSKTXWXKYQJF-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)OOS([O-])=O VAZSKTXWXKYQJF-UHFFFAOYSA-N 0.000 claims description 4
- 229910001870 ammonium persulfate Inorganic materials 0.000 claims description 4
- 239000012874 anionic emulsifier Substances 0.000 claims description 4
- CQEYYJKEWSMYFG-UHFFFAOYSA-N butyl acrylate Chemical compound CCCCOC(=O)C=C CQEYYJKEWSMYFG-UHFFFAOYSA-N 0.000 claims description 4
- 229910001869 inorganic persulfate Inorganic materials 0.000 claims description 4
- USHAGKDGDHPEEY-UHFFFAOYSA-L potassium persulfate Chemical compound [K+].[K+].[O-]S(=O)(=O)OOS([O-])(=O)=O USHAGKDGDHPEEY-UHFFFAOYSA-L 0.000 claims description 4
- PNXMTCDJUBJHQJ-UHFFFAOYSA-N propyl prop-2-enoate Chemical compound CCCOC(=O)C=C PNXMTCDJUBJHQJ-UHFFFAOYSA-N 0.000 claims description 4
- 235000019333 sodium laurylsulphate Nutrition 0.000 claims description 4
- CHQMHPLRPQMAMX-UHFFFAOYSA-L sodium persulfate Substances [Na+].[Na+].[O-]S(=O)(=O)OOS([O-])(=O)=O CHQMHPLRPQMAMX-UHFFFAOYSA-L 0.000 claims description 4
- 125000003903 2-propenyl group Chemical group [H]C([*])([H])C([H])=C([H])[H] 0.000 claims description 3
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 claims description 3
- OKKRPWIIYQTPQF-UHFFFAOYSA-N Trimethylolpropane trimethacrylate Chemical compound CC(=C)C(=O)OCC(CC)(COC(=O)C(C)=C)COC(=O)C(C)=C OKKRPWIIYQTPQF-UHFFFAOYSA-N 0.000 claims description 3
- SMVRDGHCVNAOIN-UHFFFAOYSA-L disodium;1-dodecoxydodecane;sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O.CCCCCCCCCCCCOCCCCCCCCCCCC SMVRDGHCVNAOIN-UHFFFAOYSA-L 0.000 claims description 3
- 238000001914 filtration Methods 0.000 claims description 3
- 238000001816 cooling Methods 0.000 claims description 2
- 230000001804 emulsifying effect Effects 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 claims description 2
- 150000002978 peroxides Chemical class 0.000 claims description 2
- 150000004965 peroxy acids Chemical class 0.000 claims description 2
- 125000000751 azo group Chemical group [*]N=N[*] 0.000 claims 1
- 239000003792 electrolyte Substances 0.000 abstract description 7
- 230000009286 beneficial effect Effects 0.000 abstract description 4
- 230000008961 swelling Effects 0.000 abstract description 4
- 150000001735 carboxylic acids Chemical class 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 21
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 8
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 7
- -1 polyethylene Polymers 0.000 description 7
- 229920003048 styrene butadiene rubber Polymers 0.000 description 7
- 239000002174 Styrene-butadiene Substances 0.000 description 6
- 239000011149 active material Substances 0.000 description 6
- 239000000956 alloy Substances 0.000 description 6
- 229910045601 alloy Inorganic materials 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 6
- 238000004090 dissolution Methods 0.000 description 6
- 238000010992 reflux Methods 0.000 description 6
- 239000000853 adhesive Substances 0.000 description 5
- 230000001070 adhesive effect Effects 0.000 description 5
- 239000001768 carboxy methyl cellulose Substances 0.000 description 5
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 5
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 5
- 239000002002 slurry Substances 0.000 description 5
- MTAZNLWOLGHBHU-UHFFFAOYSA-N butadiene-styrene rubber Chemical compound C=CC=C.C=CC1=CC=CC=C1 MTAZNLWOLGHBHU-UHFFFAOYSA-N 0.000 description 4
- 238000000518 rheometry Methods 0.000 description 4
- 239000011115 styrene butadiene Substances 0.000 description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 239000004615 ingredient Substances 0.000 description 3
- 239000004816 latex Substances 0.000 description 3
- 229920000126 latex Polymers 0.000 description 3
- 229910052744 lithium Inorganic materials 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 125000002843 carboxylic acid group Chemical group 0.000 description 2
- 239000007772 electrode material Substances 0.000 description 2
- 239000011267 electrode slurry Substances 0.000 description 2
- 229910021389 graphene Inorganic materials 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 238000006386 neutralization reaction Methods 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 239000007774 positive electrode material Substances 0.000 description 2
- FBCQUCJYYPMKRO-UHFFFAOYSA-N prop-2-enyl 2-methylprop-2-enoate Chemical compound CC(=C)C(=O)OCC=C FBCQUCJYYPMKRO-UHFFFAOYSA-N 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- FYRWKWGEFZTOQI-UHFFFAOYSA-N 3-prop-2-enoxy-2,2-bis(prop-2-enoxymethyl)propan-1-ol Chemical compound C=CCOCC(CO)(COCC=C)COCC=C FYRWKWGEFZTOQI-UHFFFAOYSA-N 0.000 description 1
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 239000002033 PVDF binder Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 description 1
- 229910021383 artificial graphite Inorganic materials 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 239000002041 carbon nanotube Substances 0.000 description 1
- 229910021393 carbon nanotube Inorganic materials 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 239000006257 cathode slurry Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000014509 gene expression Effects 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910003002 lithium salt Inorganic materials 0.000 description 1
- 159000000002 lithium salts Chemical class 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910021382 natural graphite Inorganic materials 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- WXZMFSXDPGVJKK-UHFFFAOYSA-N pentaerythritol Chemical compound OCC(CO)(CO)CO WXZMFSXDPGVJKK-UHFFFAOYSA-N 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920006254 polymer film Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- 239000002562 thickening agent Substances 0.000 description 1
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Compositions Of Macromolecular Compounds (AREA)
Abstract
The invention discloses a rheology modifier for a lithium ion battery cathode, a preparation method of the rheology modifier and the lithium ion battery cathode. A lithium ion battery negative electrode comprising a rheology modifier. The rheology modifier is obtained by emulsion polymerization of the following components: 20 to 51 weight percent of mixed monomer, 48 to 79.8 weight percent of deionized water, 0.02 to 3 weight percent of emulsifier and 0.01 to 1 weight percent of initiator; the mixed monomer is prepared by emulsion polymerization of the following monomers: at least one unsaturated carboxylic acid monomer accounting for 20 to 44.5 weight percent of the mixed monomer and at least one acrylic acid C accounting for 55 to 79.8 weight percent of the mixed monomer 1 ‑C 8 Alkyl ester and cross-linking monomer accounting for 0.1-2 wt% of the mixed monomer. The rheology modifier obtained by the invention has higher swelling multiple in the electrolyte, does not obstruct the conduction of lithium ions, and is beneficial to reducing the internal resistance of the battery.
Description
Technical Field
The invention relates to the technical field of aluminum battery materials, in particular to a rheology modifier for a lithium ion battery cathode, a preparation method of the rheology modifier and the lithium ion battery cathode.
Background
The lithium ion battery is a rechargeable battery with wide application prospect, has high energy density, long service life, small volume, no maintenance and environmental friendliness, is favored by various industries, is already moved from the fields of mobile phones, notebook computers and the like to the fields of electric bicycles, electric automobiles, energy storage and various portable devices, and is an ideal mobile power supply. The lithium ion battery mainly comprises a positive electrode, a negative electrode, a diaphragm and electrolyte. The lithium ion battery mainly comprises a positive electrode, a negative electrode, a diaphragm and electrolyte. The positive electrode and the negative electrode are formed by mixing active materials, conductive agents, adhesives and the like into slurry and then coating the slurry on a current collector. The negative active material is typically a carbon material. The positive electrode active material is generally a lithium-containing compound. The battery separator is usually a polymer film having micropores such as polyethylene and polypropylene. The electrolyte is prepared by dissolving lithium salt, such as lithium hexafluorophosphate, etc. in carbonate organic solvent.
In lithium ion battery electrodes, the electrode active material determines the energy density of the battery. The conductive agent can affect the specific capacity and rate charge and discharge capacity of the battery. The adhesive is used for adhering the electrode active material and the conductive agent to the metal current collector to ensure that a stable pole piece structure is formed. Although the amount of binder is typically within 3%, it has a large effect on the actual capacity, rate capability and cycle life of the battery.
In the preparation process of the negative electrode plate of the lithium ion battery, currently used adhesives are mainly styrene butadiene latex (SBR) and carboxymethyl cellulose (CMC), as disclosed in chinese patent No. CN105098190A, which discloses a negative electrode for a rechargeable lithium battery, which includes a negative active material and a binder, wherein the binder may include carboxymethyl cellulose, polyvinyl alcohol, and styrene-butadiene rubber. In some embodiments, a binder may be obtained by mixing two or more of these materials, which may improve flexibility, adhesiveness, and impregnability of the anode even if the anode is thick. Specifically, the styrene-butadiene latex has good binding capacity to negative active materials such as graphite and has good flexibility. The main role of carboxymethyl cellulose in the electrode preparation process is to avoid precipitation of the active material, stabilize the slurry and rheology adjustment. The carboxymethyl cellulose and the styrene-butadiene latex can provide good electrochemical performance after being compounded, but because the compounded adhesive is in the electrolyte, the carboxymethyl cellulose can block lithium ion transmission due to low swelling multiple, and the internal resistance of the lithium ion battery is high.
Disclosure of Invention
In order to make up for the defects of the prior art, the invention provides a rheology modifier for a lithium ion battery cathode, a preparation method thereof and the lithium ion battery cathode.
The technical problem to be solved by the invention is realized by the following technical scheme:
the invention provides a lithium ion battery cathode, which comprises the following raw materials in percentage by weight: 95 to 98wt% of active material, 0.1 to 2wt% of conductive agent, 0.5 to 2wt% of rheology modifier and 1 to 2wt% of binder; wherein,
the rheology modifier is obtained by emulsion polymerization of the following components: 20 to 51wt% of mixed monomer, 48 to 79.8wt% of deionized water, 0.02 to 3wt% of emulsifier and 0.01 to 1wt% of initiator;
the mixed monomer is prepared fromThe composition comprises the following components: at least one unsaturated carboxylic acid monomer accounting for 20 to 44.5 weight percent of the mixed monomer, and at least one acrylic acid C accounting for 55 to 79.8 weight percent of the mixed monomer 1 -C 8 Alkyl ester and crosslinking monomer accounting for 0.1 to 2wt percent of the mixed monomer.
The negative active material is at least one selected from artificial graphite, natural graphite, silicon carbon, lithium titanate, graphene, tin oxide, tin-based composite oxide, tin-based alloy, silicon-based alloy, germanium-based alloy, aluminum-based alloy, antimony-based alloy and magnesium-based alloy.
The conductive agent is selected from at least one of graphite, carbon black, acetylene black, graphene, carbon fiber and carbon nanotube.
The second object of the invention provides a rheology modifier for a lithium ion battery cathode, which is obtained by emulsion polymerization of the following components: 20 to 51wt% of mixed monomers, 48 to 79.8wt% of deionized water, 0.02 to 3wt% of emulsifiers and 0.01 to 1wt% of initiators, wherein the mixed monomers account for the total weight of the emulsion;
the mixed monomer consists of the following components: at least one unsaturated carboxylic acid monomer accounting for 20 to 44.5 weight percent of the mixed monomer, at least one acrylic acid C1-C8 alkyl ester accounting for 55 to 79.8 weight percent of the mixed monomer and a crosslinking monomer accounting for 0.1 to 2weight percent of the mixed monomer.
Further, in the present invention, the unsaturated carboxylic acid monomer is selected from acrylic acid and/or methacrylic acid.
Further, in the present invention, the acrylic acid C 1 -C 8 The alkyl ester is at least one selected from methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate and isooctyl acrylate.
Further, in the present invention, the crosslinking monomer is any one selected from the group consisting of allyl (meth) acrylate, diallyl phthalate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, and pentaerythritol triallyl ester.
Further, in the present invention, the emulsifier is an anionic emulsifier.
Further, in the present invention, the anionic emulsifier is at least one selected from the group consisting of sodium lauryl sulfate, sodium dodecylbenzenesulfonate and sodium lauryl ether sulfate.
Further, in the present invention, the initiator is selected from one or more of water-soluble inorganic persulfate, peroxide, peroxyacid, and azo compound.
Further, in the present invention, the water-soluble inorganic persulfate is at least one selected from the group consisting of sodium persulfate, potassium persulfate and ammonium persulfate.
The third object of the present invention is to provide a method for preparing the rheology modifier, which comprises the following steps:
step 1: adding part of ionized water, part of emulsifier and monomer into a pre-emulsification bottle, introducing nitrogen, starting stirring, and emulsifying to prepare pre-emulsion;
step 2: adding the rest of deionized water and the rest of emulsifier into a round-bottom flask, introducing nitrogen, stirring, and heating to 70-90 ℃;
and step 3: adding an initiator into the round-bottom flask obtained in the step 2 after the temperature rises to 70-90 ℃;
and 4, step 4: and (3) dropwise adding the pre-emulsion in the pre-emulsification bottle in the step 1 into the step 3 round-bottom flask for 60 to 300 minutes.
And 5: and after the pre-emulsion is dripped, continuously preserving the heat for 30 to 300 minutes, and cooling and filtering to obtain the rheology modifier after heat preservation is finished.
The invention has the following beneficial effects:
the rheology modifier obtained by the invention has higher swelling multiple in the electrolyte, does not obstruct the conduction of lithium ions, and is beneficial to reducing the internal resistance of the battery.
Detailed Description
The raw materials and equipment used in the invention are common raw materials and equipment in the field if not specified; the methods used in the present invention are conventional in the art unless otherwise specified.
Unless otherwise defined, terms used in the present specification have the same meaning as those generally understood by those skilled in the art, but in case of conflict, the definitions in the present specification shall control.
The use of "including," "comprising," "containing," "having," or other variations thereof herein, is meant to encompass the non-exclusive inclusion, as such terms are not to be construed. The term "comprising" means that other steps and ingredients can be added that do not affect the end result. The term "comprising" also includes the terms "consisting of and" consisting essentially of "\82303030; and" comprising of "\8230". The compositions and methods/processes of the present invention comprise, consist of, and consist essentially of the essential elements and limitations described herein, as well as any of the additional or optional ingredients, components, steps, or limitations described herein.
All numbers or expressions referring to quantities of ingredients, process conditions, etc. used in the specification and claims are to be understood as modified in all instances by the term "about". All ranges directed to the same component or property are inclusive of the endpoints, and independently combinable. Because these ranges are continuous, they include every value between the minimum and maximum values. It should also be understood that any numerical range recited herein is intended to include all sub-ranges within that range.
The invention provides a lithium ion battery cathode which is prepared from the following raw materials in percentage by weight: 95 to 98wt% of active material, 0.1 to 2wt% of conductive agent, 0.5 to 2wt% of rheology modifier and 1 to 2wt% of binder.
The rheology modifier is prepared by emulsion polymerization of the following components: 20 to 51wt% of mixed monomer, 48 to 79.8wt% of deionized water, 0.02 to 3wt% of emulsifier and 0.01 to 1wt% of initiator;
the mixed monomer consists of the following components: at least one unsaturated carboxylic acid monomer accounting for 20 to 44.5 weight percent of the mixed monomer, and at least one acrylic acid C accounting for 55 to 79.8 weight percent of the mixed monomer 1 -C 8 Alkyl ester and crosslinking monomer accounting for 0.1 to 2wt percent of the mixed monomer.
The unsaturated carboxylic acid monomer in the mixed monomer is selected from acrylic acid or methacrylic acid or a mixture of the acrylic acid and the methacrylic acid. After the pH value of the acrylic thickener is adjusted to be neutral or alkaline, carboxylic acid groups can be changed into carboxylate ions, molecular chains are stretched through electrostatic repulsion among the carboxylate ions, so that emulsion ions are greatly swelled, a thickening effect is generated, and the aim of rheology adjustment is fulfilled. Therefore, a carboxylic acid group-containing polymeric monomer is indispensable, and the amount needs to be in a certain range. Too much amount may result in instability during emulsion polymerization and breaking of emulsion. If the amount of the catalyst is too small, the amount of carboxylate ions after neutralization is insufficient, the molecular chain extension is insufficient, and the desired viscosity cannot be achieved.
Acrylic acid C in the mixed monomer 1 -C 8 Alkyl esters include, but are not limited to, methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate, and isooctyl acrylate. Acrylic acid C in the mixed monomers 1 -C 8 The alkyl ester can be used alone or in combination.
The crosslinking monomer comprises one of allyl (meth) acrylate, diallyl phthalate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate and pentaerythritol triallyl. The presence of a crosslinking monomer is also necessary. The crosslinking monomer is too little, and the polymer molecule is in a monomolecular dissolved state after neutralization, so that the aim of rheological adjustment cannot be achieved. Too much crosslinking monomer can make the neutralized polymer molecule difficult to swell in large scale, and also can cause poor rheological control effect.
The present invention will be described in detail with reference to examples, which are only preferred embodiments of the present invention and are not intended to limit the present invention.
Example 1
A preparation method of a rheology modifier comprises the following steps:
385g of deionized water and 0.3g of sodium lauryl sulfate were put into a 2L pre-emulsification bottle, and after complete dissolution with stirring, 60g of methacrylic acid, 234g of ethyl acrylate and 6g of allyl methacrylate were added to continue emulsification with stirring.
800g of deionized water were added to a round bottom flask with thermometer, reflux condenser, nitrogen inlet, and stirrer, stirring was turned on, nitrogen was admitted for 30min, and the temperature was raised to 85 ℃.
After the temperature had risen to 85 deg.C, 0.15g of sodium persulfate was added to the round-bottom flask and the dropwise addition of the pre-emulsion in the pre-emulsification bottle was started for 60min. After the dropwise addition is finished, the reaction is continued for 300min under heat preservation, and then the product is obtained by filtration.
Example 2
A preparation method of the rheology modifier comprises the following steps:
400g of deionized water and 0.68g of sodium lauryl ether sulfate were added to a 2L pre-emulsification bottle, and after complete dissolution with stirring, 135g of methacrylic acid, 105g of ethyl acrylate, 205 g of butyl acrylate and 4.5g of allyl methacrylate were added, and the emulsification was continued with stirring.
650g of deionized water were added to a round bottom flask with thermometer, reflux condenser, nitrogen inlet, and stirrer, stirring was turned on, nitrogen was admitted for 30min, and the temperature was raised to 80 ℃.
After the temperature had risen to 80 ℃, 0.45g of sodium persulfate was added to the round-bottom flask and the dropwise addition of the pre-emulsion in the pre-emulsification bottle was started for 300min. After the dropwise addition is finished, the reaction is continued for 30 minutes under the condition of heat preservation to obtain a product.
Example 3
A preparation method of a rheology modifier comprises the following steps:
300g of deionized water and 2.1g of sodium dodecylbenzenesulfonate were added to a 2L pre-emulsification bottle, and after complete dissolution by stirring, 190g of methacrylic acid, 20g of acrylic acid, 280g of ethyl acrylate, 107 g of isooctyl acrylate and 3g of trimethylolpropane triacrylate were added, and the emulsification was continued with stirring.
600g of deionized water was added to a round bottom flask with thermometer, reflux condenser, nitrogen inlet, and stirrer, stirring was turned on, nitrogen was admitted for 30min, and the temperature was raised to 80 ℃.
After the temperature had risen to 80 ℃, 3g of potassium persulfate was added to the round bottom flask and the dropwise addition of the pre-emulsion in the pre-emulsion bottle was started for 120min. After the dropwise addition is finished, the reaction is continued for 180 minutes under the condition of heat preservation, and then a product is obtained.
Example 4
A preparation method of a rheology modifier comprises the following steps:
300g of deionized water and 6.75g of sodium dodecylbenzenesulfonate are added into a 2L pre-emulsification bottle, and after complete dissolution under stirring, 330g of methacrylic acid, 111.25g of methyl acrylate, 200.5g of ethyl acrylate, 100g of propyl acrylate and 0.8g of pentaerythritol triallyl ether are added, and the emulsification under stirring is continued.
To a round bottom flask with thermometer, reflux condenser, nitrogen inlet and stirrer was added 420g of deionized water, stirring was turned on, nitrogen was admitted for 30min, and the temperature was raised to 75 ℃.
After the temperature had risen to 75 ℃, 7.5g of potassium persulfate was added to the round-bottom flask and the dropwise addition of the pre-emulsion in the pre-emulsification bottle was started for 180min. After the dropwise addition is finished, the reaction is continued for 180 minutes under the condition of heat preservation, and then a product is obtained.
Example 5
A preparation method of the rheology modifier comprises the following steps:
300g of deionized water and 3.15g of sodium lauryl sulfate were added to a 2L pre-emulsification bottle, and after complete dissolution with stirring, 90g of methacrylic acid, 15g of acrylic acid, 114.75g of methyl acrylate, 300g of ethyl acrylate and 1.05g of diallyl phthalate were added, and stirring was continued for emulsification.
675g of deionized water was added to a round bottom flask with thermometer, reflux condenser, nitrogen inlet and stirrer, stirring was turned on, nitrogen was admitted for 30min and the temperature was raised to 90 ℃.
After the temperature had risen to 90 ℃, 1.1g of ammonium persulfate was added to the round-bottom flask and the dropwise addition of the pre-emulsion in the pre-emulsification bottle was started for 60min. After the dropwise addition is finished, the reaction is continued for 180 minutes under the condition of heat preservation, and then the product is obtained.
Example 6
A preparation method of a rheology modifier comprises the following steps:
300g of deionized water and 1.5g of sodium dodecylbenzenesulfonate were added to a 2L preemulsification bottle, and after complete dissolution by stirring, 130g of methacrylic acid, 20g of acrylic acid, 118g of methyl acrylate, 200g of ethyl acrylate and 3g of diallyl phthalate were added, and stirring and emulsification were continued.
600g of deionized water was added to a round bottom flask with thermometer, reflux condenser, nitrogen inlet, and stirrer, stirring was turned on, nitrogen was admitted for 30min, and the temperature was raised to 85 ℃.
After the temperature had risen to 85 ℃,1.2 g of ammonium persulfate was added to the round-bottom flask and the dropwise addition of the pre-emulsion in the pre-emulsification bottle was started for 160min. After the dropwise addition is finished, the reaction is continued for 120 minutes under the condition of heat preservation to obtain the product.
Comparative example 1
The preparation process is essentially the same as in example 6, except that no crosslinking monomer is used. The emulsion prepared in this comparative example did not have rheology adjusting capability.
Comparative example 2
The procedure was substantially the same as in example 6, except that methacrylic acid and acrylic acid were not used. The emulsion prepared in this comparative example did not have rheology adjusting capability.
Comparative example 3
The procedure was substantially the same as in example 6, except that no acrylic monomer was used, and only methacrylic acid, acrylic acid and a crosslinking monomer were used. In the preparation process of the comparative example, the monomers could not be pre-emulsified and emulsion polymerization could not be carried out normally.
Comparative example 4
The procedure was substantially the same as in example 6 except that 65g of methacrylic acid and 5g of acrylic acid were contained in the mixed monomers in an amount of 17.9% by weight.
Comparative example 5
The preparation was substantially the same as in example 6 except that 270g of methacrylic acid and 80g of acrylic acid were contained in 47.5% by weight of the mixed monomers. This comparative example demulsified during the polymerization.
Comparative example 6
The preparation was substantially the same as in example 6 except that 0.25g of diallyl phthalate was used in an amount of 0.05wt% based on the mixed monomers.
Comparative example 7
The preparation was substantially the same as in example 6 except that 15g of diallyl phthalate, which was 3.11wt% of the mixed monomers, was used.
Testing the internal resistance of the battery: preparing a 550mAh soft package battery according to the following material proportion, testing internal resistance after formation of a battery cell, adjusting the pH value of cathode slurry to 7-9 by using LiOH in the battery preparation process, and testing the viscosity of the slurry.
And (3) positive electrode material: 96.8wt% of ternary active material, 2wt% of conductive agent and 1.2wt% of PVDF adhesive.
And (3) cathode material: 96.4wt% graphite, 1wt% conductive agent, 1.4wt% rheology modifier or carboxymethyl cellulose (CMC) of each of the above examples, 1.2wt% styrene-butadiene emulsion (SBR).
The results of the negative electrode slurry viscosity and the internal resistance of the battery were as follows:
| rheology modifier | viscosity/mPa.s of negative electrode slurry | Internal resistance of battery/m omega |
| Example 1 | 3784 | 50.1 |
| Example 2 | 4453 | 49.7 |
| Example 3 | 5254 | 47.8 |
| Example 4 | 7634 | 47.3 |
| Example 5 | 4265 | 50.5 |
| Example 6 | 4746 | 50.8 |
| Carboxymethyl cellulose | 4355 | 58.7 |
| Comparative example 1 | 546 | / |
| Comparative example 2 | 268 | / |
| Comparative example 3 | / | / |
| Comparative example 4 | 988 | / |
| Comparative example 5 | / | / |
| Comparative example 6 | 1056 | / |
| Comparison ofExample 7 | 849 | / |
In comparative examples 1 to 7, emulsion polymerization in comparative example 3 and comparative example 5 did not proceed normally and no usable products could be prepared. Comparative examples 1, 2, 4, 6 and 7 were tested because the prepared slurry had too low viscosity and the active material and conductive agent were easily sedimented and could not be applied to uniform pole pieces. As can be seen from Table 1, the rheology modifier obtained in the embodiments 1-6 of the invention has a higher swelling ratio in the electrolyte, does not hinder the lithium ion conduction, and is beneficial to reducing the internal resistance of the battery.
It should be understood that the above-described embodiments are only a part of the embodiments of the present application, and not all of the embodiments, and do not limit the scope of the present application. This application is capable of embodiments in many different forms and is provided for the purpose of enabling a thorough understanding of the disclosure of the application. Although the present application has been described in detail with reference to the foregoing embodiments, it will be apparent to one skilled in the art that the present application may be practiced without modification or with equivalents of some of the features described in the foregoing embodiments. All equivalent structures made by using the content of the specification of the present application are directly or indirectly applied to other related technical fields, and the same is within the protection scope of the present application.
Claims (10)
1. The lithium ion battery cathode is characterized by comprising the following raw materials in percentage by weight: 95-98 wt% of negative electrode active material, 0.1-2 wt% of conductive agent, 0.5-2 wt% of rheology modifier and 1-2 wt% of binder; wherein,
the rheology modifier is obtained by emulsion polymerization of the following components: 20 to 51 weight percent of mixed monomer, 48 to 79.8 weight percent of deionized water, 0.02 to 3 weight percent of emulsifier and 0.01 to 1 weight percent of initiator;
the mixed monomer consists of the following components: at least one unsaturated carboxylic acid monomer accounting for 20 to 44.5 weight percent of the mixed monomer and at least one acrylic acid C accounting for 55 to 79.8 weight percent of the mixed monomer 1 -C 8 Alkyl ester and cross-linking monomer accounting for 0.1-2 wt% of the mixed monomer.
2. The rheology modifier for the negative electrode of the lithium ion battery is characterized by being prepared by emulsion polymerization of the following components: 20 to 51 weight percent of mixed monomer, 48 to 79.8 weight percent of deionized water, 0.02 to 3 weight percent of emulsifier and 0.01 to 1 weight percent of initiator;
the mixed monomer consists of the following components: at least one unsaturated carboxylic acid monomer accounting for 20 to 44.5 weight percent of the mixed monomer and at least one acrylic acid C accounting for 55 to 79.8 weight percent of the mixed monomer 1 -C 8 Alkyl ester and cross-linking monomer accounting for 0.1-2 wt% of the mixed monomer.
3. The rheology modifier for negative electrodes of lithium ion batteries according to claim 2, characterized in that said unsaturated carboxylic monomers are selected from acrylic acid and/or methacrylic acid.
4. The rheology modifier for negative electrodes of lithium ion batteries according to claim 2, characterized in that said acrylic acid C 1 -C 8 The alkyl ester is at least one selected from methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate and isooctyl acrylate.
5. The rheology modifier for negative electrodes of lithium ion batteries according to claim 2, characterized in that the crosslinking monomer is any one selected from allyl (meth) acrylate, diallyl phthalate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, and pentaerythritol triallyl ester.
6. The rheology modifier for negative electrodes of lithium ion batteries according to claim 2, characterized in that the emulsifier is an anionic emulsifier.
7. The rheology modifier for negative electrodes of lithium ion batteries according to claim 6, characterized in that said anionic emulsifier is selected from at least one of sodium lauryl sulfate, sodium dodecylbenzenesulfonate and sodium lauryl ether sulfate.
8. The rheology modifier for negative electrodes of lithium ion batteries according to claim 2, characterized in that said initiator is selected from one or more of water-soluble inorganic persulfates, peroxides, peroxyacids and azo compounds.
9. The rheology modifier for negative electrodes of lithium ion batteries according to claim 8, characterized in that the water-soluble inorganic persulfate is selected from at least one of sodium persulfate, potassium persulfate and ammonium persulfate.
10. A process for the preparation of a rheology modifier according to any one of claims 2 to 9 characterised in that it comprises the following steps:
step 1: adding part of ionized water, part of emulsifier and monomer into a pre-emulsification bottle, introducing nitrogen, starting stirring, and emulsifying to prepare pre-emulsion;
step 2: adding the rest of deionized water and the rest of emulsifier into a round-bottom flask, introducing nitrogen, stirring and heating to 70-90 ℃;
and step 3: adding an initiator into the round-bottom flask obtained in the step 2 after the temperature rises to 70-90 ℃;
and 4, step 4: and (3) dropwise adding the pre-emulsion in the pre-emulsification bottle in the step 1 into the step 3 round-bottom flask for 60 to 300 minutes.
And 5: and after the pre-emulsion is dripped, continuously preserving the heat for 30 to 300 minutes, and cooling and filtering to obtain the rheology modifier after heat preservation is finished.
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