CN117293314A - Adhesive for improving electrical property of silicon-based negative electrode, battery negative electrode and application - Google Patents
Adhesive for improving electrical property of silicon-based negative electrode, battery negative electrode and application Download PDFInfo
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- CN117293314A CN117293314A CN202311239734.0A CN202311239734A CN117293314A CN 117293314 A CN117293314 A CN 117293314A CN 202311239734 A CN202311239734 A CN 202311239734A CN 117293314 A CN117293314 A CN 117293314A
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- negative electrode
- parts
- battery
- silicon
- adhesive
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- 230000001070 adhesive effect Effects 0.000 title claims abstract description 113
- 239000000853 adhesive Substances 0.000 title claims abstract description 110
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims abstract description 27
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 27
- 239000010703 silicon Substances 0.000 title claims abstract description 27
- 239000002002 slurry Substances 0.000 claims abstract description 42
- 238000000034 method Methods 0.000 claims abstract description 29
- 239000011248 coating agent Substances 0.000 claims abstract description 13
- 238000000576 coating method Methods 0.000 claims abstract description 13
- 238000001035 drying Methods 0.000 claims abstract description 13
- 238000002156 mixing Methods 0.000 claims abstract description 13
- 238000005096 rolling process Methods 0.000 claims abstract description 13
- 239000006258 conductive agent Substances 0.000 claims abstract description 12
- 239000011866 silicon-based anode active material Substances 0.000 claims abstract description 7
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 228
- IXPNQXFRVYWDDI-UHFFFAOYSA-N 1-methyl-2,4-dioxo-1,3-diazinane-5-carboximidamide Chemical compound CN1CC(C(N)=N)C(=O)NC1=O IXPNQXFRVYWDDI-UHFFFAOYSA-N 0.000 claims description 68
- 239000000661 sodium alginate Substances 0.000 claims description 66
- 235000010413 sodium alginate Nutrition 0.000 claims description 66
- 229940005550 sodium alginate Drugs 0.000 claims description 66
- 229910001416 lithium ion Inorganic materials 0.000 claims description 56
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims description 54
- 239000004793 Polystyrene Substances 0.000 claims description 54
- 229920001577 copolymer Polymers 0.000 claims description 54
- 229920002223 polystyrene Polymers 0.000 claims description 54
- KAKZBPTYRLMSJV-UHFFFAOYSA-N vinyl-ethylene Natural products C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 claims description 54
- 229920000609 methyl cellulose Polymers 0.000 claims description 47
- 239000001923 methylcellulose Substances 0.000 claims description 47
- 235000010981 methylcellulose Nutrition 0.000 claims description 47
- 229920002134 Carboxymethyl cellulose Polymers 0.000 claims description 44
- 239000002202 Polyethylene glycol Substances 0.000 claims description 44
- 239000001768 carboxy methyl cellulose Substances 0.000 claims description 44
- 235000010948 carboxy methyl cellulose Nutrition 0.000 claims description 44
- 239000008112 carboxymethyl-cellulose Substances 0.000 claims description 44
- 229920001223 polyethylene glycol Polymers 0.000 claims description 44
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 35
- 239000008367 deionised water Substances 0.000 claims description 29
- 229910021641 deionized water Inorganic materials 0.000 claims description 29
- 239000003792 electrolyte Substances 0.000 claims description 22
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 17
- 239000002131 composite material Substances 0.000 claims description 15
- 239000003795 chemical substances by application Substances 0.000 claims description 12
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 8
- 239000002041 carbon nanotube Substances 0.000 claims description 8
- 235000021355 Stearic acid Nutrition 0.000 claims description 4
- 239000011230 binding agent Substances 0.000 claims description 4
- 229910002804 graphite Inorganic materials 0.000 claims description 4
- 239000010439 graphite Substances 0.000 claims description 4
- 239000001866 hydroxypropyl methyl cellulose Substances 0.000 claims description 4
- 235000010979 hydroxypropyl methyl cellulose Nutrition 0.000 claims description 4
- 229920003088 hydroxypropyl methyl cellulose Polymers 0.000 claims description 4
- UFVKGYZPFZQRLF-UHFFFAOYSA-N hydroxypropyl methyl cellulose Chemical compound OC1C(O)C(OC)OC(CO)C1OC1C(O)C(O)C(OC2C(C(O)C(OC3C(C(O)C(O)C(CO)O3)O)C(CO)O2)O)C(CO)O1 UFVKGYZPFZQRLF-UHFFFAOYSA-N 0.000 claims description 4
- 239000005543 nano-size silicon particle Substances 0.000 claims description 4
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 claims description 4
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 claims description 4
- 239000008117 stearic acid Substances 0.000 claims description 4
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 3
- OBNDGIHQAIXEAO-UHFFFAOYSA-N [O].[Si] Chemical compound [O].[Si] OBNDGIHQAIXEAO-UHFFFAOYSA-N 0.000 claims description 3
- 239000006229 carbon black Substances 0.000 claims description 3
- 235000015165 citric acid Nutrition 0.000 claims description 3
- GVGUFUZHNYFZLC-UHFFFAOYSA-N dodecyl benzenesulfonate;sodium Chemical compound [Na].CCCCCCCCCCCCOS(=O)(=O)C1=CC=CC=C1 GVGUFUZHNYFZLC-UHFFFAOYSA-N 0.000 claims description 3
- 229910021389 graphene Inorganic materials 0.000 claims description 3
- 239000003273 ketjen black Substances 0.000 claims description 3
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 3
- 239000002153 silicon-carbon composite material Substances 0.000 claims description 3
- 229940080264 sodium dodecylbenzenesulfonate Drugs 0.000 claims description 3
- LNAZSHAWQACDHT-XIYTZBAFSA-N (2r,3r,4s,5r,6s)-4,5-dimethoxy-2-(methoxymethyl)-3-[(2s,3r,4s,5r,6r)-3,4,5-trimethoxy-6-(methoxymethyl)oxan-2-yl]oxy-6-[(2r,3r,4s,5r,6r)-4,5,6-trimethoxy-2-(methoxymethyl)oxan-3-yl]oxyoxane Chemical compound CO[C@@H]1[C@@H](OC)[C@H](OC)[C@@H](COC)O[C@H]1O[C@H]1[C@H](OC)[C@@H](OC)[C@H](O[C@H]2[C@@H]([C@@H](OC)[C@H](OC)O[C@@H]2COC)OC)O[C@@H]1COC LNAZSHAWQACDHT-XIYTZBAFSA-N 0.000 claims description 2
- 239000002134 carbon nanofiber Substances 0.000 claims description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical class C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 2
- 239000000463 material Substances 0.000 abstract description 8
- 238000004519 manufacturing process Methods 0.000 abstract description 4
- 239000000203 mixture Substances 0.000 abstract description 4
- 239000011871 silicon-based negative electrode active material Substances 0.000 description 44
- 238000004804 winding Methods 0.000 description 21
- 230000000052 comparative effect Effects 0.000 description 18
- 230000008569 process Effects 0.000 description 16
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 15
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 15
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 15
- 238000012360 testing method Methods 0.000 description 15
- 238000005520 cutting process Methods 0.000 description 10
- 238000002360 preparation method Methods 0.000 description 10
- 230000001105 regulatory effect Effects 0.000 description 10
- 238000009966 trimming Methods 0.000 description 10
- 239000000126 substance Substances 0.000 description 8
- 239000002033 PVDF binder Substances 0.000 description 7
- 125000004185 ester group Chemical group 0.000 description 7
- 230000014759 maintenance of location Effects 0.000 description 7
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 7
- 238000007599 discharging Methods 0.000 description 6
- 238000005886 esterification reaction Methods 0.000 description 6
- 229910013716 LiNi Inorganic materials 0.000 description 5
- 229910013870 LiPF 6 Inorganic materials 0.000 description 5
- 239000004698 Polyethylene Substances 0.000 description 5
- HFCVPDYCRZVZDF-UHFFFAOYSA-N [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O Chemical compound [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O HFCVPDYCRZVZDF-UHFFFAOYSA-N 0.000 description 5
- 230000002238 attenuated effect Effects 0.000 description 5
- 238000010030 laminating Methods 0.000 description 5
- 238000011068 loading method Methods 0.000 description 5
- 239000011259 mixed solution Substances 0.000 description 5
- 238000004806 packaging method and process Methods 0.000 description 5
- 239000002210 silicon-based material Substances 0.000 description 5
- 239000013543 active substance Substances 0.000 description 4
- 125000004122 cyclic group Chemical group 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 4
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 4
- 238000009830 intercalation Methods 0.000 description 4
- 230000002687 intercalation Effects 0.000 description 4
- 238000007086 side reaction Methods 0.000 description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 3
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 3
- 238000009831 deintercalation Methods 0.000 description 3
- 230000005489 elastic deformation Effects 0.000 description 3
- 229910052744 lithium Inorganic materials 0.000 description 3
- 239000002174 Styrene-butadiene Substances 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 125000002057 carboxymethyl group Chemical group [H]OC(=O)C([H])([H])[*] 0.000 description 2
- 229920002521 macromolecule Polymers 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 238000005191 phase separation Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 238000005411 Van der Waals force Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000011149 active material Substances 0.000 description 1
- 239000010405 anode material Substances 0.000 description 1
- 239000011203 carbon fibre reinforced carbon Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 229920002301 cellulose acetate Polymers 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000006482 condensation reaction Methods 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 239000011883 electrode binding agent Substances 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 125000001183 hydrocarbyl group Chemical group 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000007773 negative electrode material Substances 0.000 description 1
- -1 on the other hand Substances 0.000 description 1
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 150000003377 silicon compounds Chemical class 0.000 description 1
- 239000002409 silicon-based active material Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/621—Binders
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J101/00—Adhesives based on cellulose, modified cellulose, or cellulose derivatives
- C09J101/08—Cellulose derivatives
- C09J101/26—Cellulose ethers
- C09J101/28—Alkyl ethers
- C09J101/284—Alkyl ethers with hydroxylated hydrocarbon radicals
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J101/00—Adhesives based on cellulose, modified cellulose, or cellulose derivatives
- C09J101/08—Cellulose derivatives
- C09J101/26—Cellulose ethers
- C09J101/28—Alkyl ethers
- C09J101/286—Alkyl ethers substituted with acid radicals
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
- C09J11/02—Non-macromolecular additives
- C09J11/06—Non-macromolecular additives organic
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
- C09J11/08—Macromolecular additives
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J125/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Adhesives based on derivatives of such polymers
- C09J125/02—Homopolymers or copolymers of hydrocarbons
- C09J125/04—Homopolymers or copolymers of styrene
- C09J125/08—Copolymers of styrene
- C09J125/10—Copolymers of styrene with conjugated dienes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/134—Electrodes based on metals, Si or alloys
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/621—Binders
- H01M4/622—Binders being polymers
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2203/00—Applications
- C08L2203/20—Applications use in electrical or conductive gadgets
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/027—Negative electrodes
-
- 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
Abstract
The invention belongs to the technical field of battery materials, and provides an adhesive for improving electrical properties of a silicon-based negative electrode, a battery negative electrode and application thereof. The battery negative electrode comprises a negative electrode current collector and a negative electrode active layer arranged on the surface of the negative electrode current collector; the negative electrode active layer is prepared by the following method: and mixing the silicon-based anode active material, the conductive agent and the adhesive to obtain anode active slurry, coating the anode active slurry on the surface of the anode current collector, and rolling and drying to form the anode active layer. The invention prepares the battery cathode by adjusting the composition and the proportion of the cathode adhesive and adding the cathode adhesive into the cathode active slurry, so that the cathode current collector and the cathode active layer in the battery cathode have good integral connectivity, thereby meeting the actual production requirement.
Description
Technical Field
The invention belongs to the technical field of battery materials, and relates to an adhesive for improving electrical properties of a silicon-based negative electrode, a battery negative electrode and application thereof.
Background
At present, a commercial lithium ion battery mainly uses graphite carbon-based negative electrode materials, but the theoretical specific capacity value is only 372mAh/g, and the requirement of an electric automobile on a battery with high specific capacity can not be met far. Among the numerous non-carbon based negative electrode candidate materials, silicon has received great attention in the field of batteries at its highest theoretical specific capacity value (4200 mAh/g). However, the silicon-based material has a huge volume change (400%) in the process of lithium ion intercalation and deintercalation, and the mechanical force generated by such severe volume shrinkage and expansion can cause the active material silicon to drop from the current collector to lose electrical contact, and lead to mechanical pulverization of the silicon, so that the specific capacity value is rapidly reduced, and finally, the battery capacity is rapidly attenuated.
Therefore, the silicon-based anode material is required to be adhered to the current collector by adopting an adhesive, the adhesive of the silicon-based material can stabilize the electrode plate structure and buffer the expansion/contraction of the electrode plate in the charge and discharge process, the adhesive of the silicon-based material is one of key factors influencing the first charge and discharge efficiency and the subsequent cycle stability of the electrode, and the adhesive with weak adhesive force cannot keep the electrical contact activity between the silicon active materials, so that the first effect of the electrode is lower and the subsequent specific capacity is attenuated, and the realization of the high-energy-density battery performance is influenced.
Currently, the most widely used electrode binders are mainly PVDF, methylcellulose and SBR. However, when PVDF and propylene carbonate in electrolyte are acted, swelling is easy to occur, so that the electrode structure is deformed, and meanwhile, the binding force is reduced, so that the capacity attenuation is faster in the battery cycle process; the carboxyl group in the methylcellulose and the hydrocarbon group on the surface of the silicon compound can be dehydrated to form stronger covalent connection, so that the structural integrity of the electrode is enhanced, but the methylcellulose has high rigidity and low elongation at break (5-8 percent) and can not completely eliminate stress, so that cracks are often generated in the repeated cycle process, and the capacity of the battery is obviously attenuated; however, SBR has a certain elasticity, but has weak binding ability, and degradation of carbon-carbon double bonds occurs during charge and discharge of the battery, resulting in failure of the adhesive.
Therefore, in order to solve the above-mentioned technical problems, it is necessary to develop a negative electrode adhesive having excellent adhesion properties and excellent binding effect, and to achieve effective suppression of volume expansion of a silicon-based material, thereby improving the electrical properties of a lithium ion battery.
Disclosure of Invention
Aiming at the defects existing in the prior art, the invention aims to provide an adhesive for improving the electrical property of a silicon-based negative electrode, a battery negative electrode and application thereof, wherein the composition and the proportion of the negative electrode adhesive are adjusted, and the negative electrode adhesive is added into negative electrode active slurry to prepare the battery negative electrode, so that a negative electrode current collector in the battery negative electrode and a negative electrode active layer have good integral connectivity, the impedance of a battery core can be reduced, and the battery negative electrode has good processability and mechanical property, thereby meeting the requirements of actual production.
To achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the invention provides an adhesive for improving electrical properties of a silicon-based negative electrode, wherein the adhesive comprises methylcellulose, citric acid, sodium alginate, polystyrene butadiene copolymer, a film forming agent and deionized water.
The silicon-based negative electrode active material can generate huge volume expansion in the circulation process, so that a negative electrode active layer is cracked and even falls off from a negative electrode current collector, and the electric connection is lost, so that the capacity of the lithium ion battery is rapidly attenuated. The invention prepares the battery cathode by adjusting the composition and the proportion of the cathode adhesive and adding the cathode adhesive into the cathode active slurry, so that the cathode current collector in the battery cathode and the cathode active layer have good interface bonding strength, and the battery cathode has good processability and mechanical property, thereby meeting the actual production requirement.
The components in the adhesive provided by the invention are functionally divided into a composite embedding component and a composite bonding component, wherein citric acid and sodium alginate form the composite embedding component, and the composite embedding component can be uniformly coated on the surface of the silicon-based negative electrode active material through chemical means and physical means. The methylcellulose and the polystyrene butadiene copolymer form a composite bonding component, wherein the polystyrene butadiene copolymer plays a physical bonding role, the methylcellulose and citric acid coated on the surface of the silicon-based negative electrode active material undergo esterification reaction to form ester bonds, a chemical connection role is played, the coated silicon-based negative electrode active material is connected by the composite bonding component through the physical bonding role and the chemical connection role to form a three-dimensional network structure, the three-dimensional network structure has more space deformation redundancy, and the volume expansion phenomenon of the silicon-based negative electrode active material in the lithium intercalation and deintercalation processes can be effectively buffered, so that good electrical connection between the negative electrode active layer and the negative electrode current collector in the circulation process is ensured, the integrity of a conductive network and an electrode structure in the negative electrode active layer is ensured, and finally the electrochemical performance of the lithium ion battery is improved.
The silicon-based negative electrode active material can generate side reaction on the surface of the silicon-based negative electrode active material after being contacted with the electrolyte, so that an SEI film is generated on the surface of the silicon-based negative electrode active material, the electrolyte is consumed in a large amount, the impedance of the lithium ion battery is increased, and the battery capacity is reduced. According to the invention, a certain amount of film forming agent is added into the adhesive, when the negative electrode active slurry is prepared, the film forming agent can be coated on the surface of the silicon-based negative electrode active material, after the film forming agent is coated on the negative electrode current collector, the surface of the silicon-based negative electrode active material is rolled and dried, so that a uniform film layer is formed on the surface of the silicon-based negative electrode active material, the silicon-based negative electrode active material in the negative electrode active layer can be effectively prevented from being directly contacted with electrolyte, the occurrence probability of side reaction is reduced, the SEI film formed by a battery core in the charge and discharge process is more stable and compact and does not thicken along with the increase of the cycle times, the compatibility of the battery negative electrode and the electrolyte is improved, and the cycle stability of the battery negative electrode is improved, so that the capacity retention rate and the cycle performance of the lithium ion battery are obviously improved.
As a preferable technical scheme of the invention, the adhesive comprises the following components in parts by mass based on 100 parts by mass of the adhesive:
12-26 parts of methyl cellulose;
10-15 parts of citric acid;
5-8 parts of sodium alginate;
10-15 parts of polystyrene butadiene copolymer;
2-5 parts of film forming agent;
the balance of deionized water.
Wherein, the mass part of the methylcellulose can be 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts or 26 parts, the mass part of the citric acid can be 10 parts, 10.5 parts, 11 parts, 11.5 parts, 12 parts, 12.5 parts, 13.5 parts, 14 parts, 14.5 parts or 15 parts, the mass part of the sodium alginate can be 5.0 parts, 5.2 parts, 5.4 parts, 5.6 parts, 5.8 parts, 6.0 parts, 6.2 parts, 6.4 parts, 6.6 parts, 6.8 parts, 7.0 parts, 7.2 parts, 7.4 parts, 7.6 parts, 7.8 parts or 8.0 parts, the mass part of the polystyrene butadiene copolymer can be 10 parts, 10.5 parts, 11 parts, 11.5 parts, 12 parts, 12.5 parts, 13.5 parts, 14.5 parts, 4.5 parts, 4.3.0 parts, 4 parts, 4.3.0 parts, 4.3 parts, 4.0 parts or 3.0 parts, 4.3 parts, 4.0 parts, or 2.0 parts, which are not limited to the other values listed in the ranges.
The effect of adding methyl cellulose into the adhesive is that:
(1) The methylcellulose molecules have a special bench-type conformation, and the methylcellulose molecules are mutually entangled through molecular forces such as hydrogen bonds, van der Waals forces and the like to form a three-dimensional space network structure. Meanwhile, the methyl cellulose can perform esterification reaction with the citric acid, and the silicon-based negative electrode active material embedded by the citric acid can be tightly locked in the three-dimensional space network structure through ester group connection with the citric acid in the three-dimensional space network structure, so that the volume expansion of the silicon-based negative electrode active material in the battery cycle process is effectively resisted;
(2) The addition of the methyl cellulose can greatly improve the water absorption rate of the adhesive, and the space volume of methyl cellulose molecules is larger, so that the molecular gaps of each component in the adhesive are increased, water molecules can enter the inside of the molecules of the components, and the water absorption and water locking capacity of the adhesive is improved;
(3) Because the methyl cellulose contains a large number of hydrophilic groups such as hydroxyl and methyl, and the like in the molecule, the hydrogen bonding between molecules is stronger along with the continuous loss of water in the adhesive in the process of preparing the negative electrode of the battery, and meanwhile, the intermolecular acting force is also increased, so that the prepared negative electrode active layer has larger tensile strength and elastic deformation rate, and is beneficial to preventing the cracking and falling of the negative electrode active layer.
The sodium alginate is added into the adhesive to play the roles of: on one hand, sodium alginate can be compounded with citric acid to embed silicon-based anode active substances, on the other hand, sodium alginate can generate a synergistic effect with methyl cellulose molecules, the space volume of carboxymethyl in the methyl cellulose molecules is larger than that of carboxyl in the molecular structure of sodium alginate, and when the methyl cellulose is compounded with sodium alginate, carboxymethyl on the methyl cellulose can stretch to penetrate between sodium alginate molecules and form hydrogen bonds with carboxyl and hydroxyl on the sodium alginate molecules, so that strong intermolecular force is generated between the methyl cellulose molecules and the sodium alginate molecules.
The silicon-based anode active material embedded by sodium alginate and citric acid can be tightly connected in a three-dimensional network structure formed by methyl cellulose molecules by intermolecular force generated between the methyl cellulose and the sodium alginate combined with an ester group functional group generated between the methyl cellulose and the citric acid.
With the increase of the addition amount of the methylcellulose, the three-dimensional network structure is more compact, so that the tensile strength and the elastic deformation rate of the anode active layer are gradually improved, and when the addition amount of the methylcellulose is 12-26 parts by mass, the tensile strength and the elastic deformation rate of the anode active layer are highest. When the addition amount of the methylcellulose exceeds 26 parts by mass, strong hydrogen bond action is formed between methylcellulose molecules, the interaction between the methylcellulose molecules and sodium alginate macromolecules is limited, the viscosity of the adhesive is reduced, meanwhile, phase separation phenomenon between the methylcellulose and the sodium alginate is caused, the phase separation situation is further amplified along with the increase of the content of the methylcellulose, and a large number of water molecules locked in a three-dimensional space network structure weaken acting force among the adhesive molecules, so that the methylcellulose macromolecule chain segments slide, and the overall mechanical property of the anode active layer is reduced.
The invention is particularly limited to 10-15 parts by mass of citric acid, and the citric acid in the invention has double functions, namely, silicon-based anode active substances are embedded; and secondly, the cellulose acetate and the methylcellulose are subjected to esterification reaction to form ester group connection. Therefore, a certain stoichiometric ratio relationship exists between the mass parts of the citric acid and the mass parts of the silicon-based negative electrode active material and the methyl cellulose, and the complete reaction between the methyl cellulose and the citric acid and the excessive amount of the citric acid can be ensured within the range of 10-15 parts defined by the invention, on one hand, a large amount of ester groups are generated through the esterification reaction of the methyl cellulose and the citric acid so as to ensure that the silicon-based negative electrode active material embedded by the citric acid can be stably connected in a three-dimensional network structure through the ester groups. On the other hand, the excessive citric acid is used for embedding the silicon-based negative electrode active material, and the citric acid can generate a covalent bond with hydroxyl groups on the surface of the silicon-based negative electrode active material through condensation reaction, so that the silicon-based negative electrode active material is chemically embedded.
The chemical bond connection between the citric acid and the silicon-based negative electrode active substance and the ester connection between the citric acid and the methyl cellulose are realized by adding the citric acid, so that the adhesive can keep stable structure and property in the electrolyte, and can effectively inhibit the volume expansion of the silicon-based negative electrode active substance in the lithium intercalation process, thereby effectively improving the electrochemical performance of the silicon-based negative electrode lithium ion battery.
As a preferable technical scheme of the invention, the methyl cellulose is carboxymethyl cellulose and/or hydroxypropyl methyl cellulose.
As a preferable technical scheme of the invention, the film forming agent is any one or a combination of at least two of polyethylene glycol, polyvinyl alcohol, sodium dodecyl benzene sulfonate and stearic acid.
In a second aspect, the present invention provides a battery anode, which includes an anode current collector and an anode active layer disposed on a surface of the anode current collector.
The negative electrode active layer is prepared by the following method:
and mixing the silicon-based anode active material, the conductive agent and the adhesive in the first aspect to obtain anode active slurry, coating the anode active slurry on the surface of the anode current collector, and rolling and drying to form the anode active layer.
As a preferred technical solution of the present invention, the mass ratio of the silicon-based anode active material, the conductive agent and the binder is (94-97): (1-3): (2-3), for example, 94:3:3, 94.5:2.5:3, 95:2:3, 95.5:1.5:3, 96:1:3, 96.5:1:2.5 or 97:1:2, but not limited to the listed values, and other non-listed values in the range of the values are equally applicable.
As a preferable technical scheme of the invention, the silicon-based negative electrode active material is any one or a combination of at least two of micron silicon, nano silicon, silicon oxygen composite material and silicon carbon composite material.
As a preferable technical scheme of the invention, the conductive agent is any one or a combination of at least two of carbon black, ketjen black, conductive graphite, carbon nano-tubes, vapor deposition carbon nano-fibers and graphene.
In a third aspect, the present invention provides a lithium ion battery cell, which includes a battery positive electrode, a separator, and a battery negative electrode according to the second aspect, which are sequentially stacked.
In a fourth aspect, the present invention provides a lithium ion battery, which includes a housing and the lithium ion battery core of the third aspect located in the housing, where an electrolyte is injected into the housing.
Compared with the prior art, the invention has the beneficial effects that:
(1) The silicon-based negative electrode active material can generate huge volume expansion in the circulation process, so that a negative electrode active layer is cracked and even falls off from a negative electrode current collector, and the electric connection is lost, so that the capacity of the lithium ion battery is rapidly attenuated. The invention prepares the battery cathode by adjusting the composition and the proportion of the cathode adhesive and adding the cathode adhesive into the cathode active slurry, so that the cathode current collector in the battery cathode and the cathode active layer have good interface bonding strength, and the battery cathode has good processability and mechanical property, thereby meeting the actual production requirement.
(2) The components in the adhesive provided by the invention are functionally divided into a composite embedding component and a composite bonding component, wherein citric acid and sodium alginate form the composite embedding component, and the composite embedding component can be uniformly coated on the surface of the silicon-based negative electrode active material through chemical means and physical means. The methylcellulose and the polystyrene butadiene copolymer form a composite bonding component, wherein the polystyrene butadiene copolymer plays a physical bonding role, the methylcellulose and citric acid coated on the surface of the silicon-based negative electrode active material undergo esterification reaction to form ester bonds, a chemical connection role is played, the coated silicon-based negative electrode active material is connected by the composite bonding component through the physical bonding role and the chemical connection role to form a three-dimensional network structure, the three-dimensional network structure has more space deformation redundancy, and the volume expansion phenomenon of the silicon-based negative electrode active material in the lithium intercalation and deintercalation processes can be effectively buffered, so that good electrical connection between the negative electrode active layer and the negative electrode current collector in the circulation process is ensured, the integrity of a conductive network and an electrode structure in the negative electrode active layer is ensured, and finally the electrochemical performance of the lithium ion battery is improved.
(3) The silicon-based negative electrode active material can generate side reaction on the surface of the silicon-based negative electrode active material after being contacted with the electrolyte, so that an SEI film is generated on the surface of the silicon-based negative electrode active material, the electrolyte is consumed in a large amount, the impedance of the lithium ion battery is increased, and the battery capacity is reduced. According to the invention, a certain amount of film forming agent is added into the adhesive, when the negative electrode active slurry is prepared, the film forming agent can be coated on the surface of the silicon-based negative electrode active material, after the film forming agent is coated on the negative electrode current collector, the surface of the silicon-based negative electrode active material is rolled and dried, so that a uniform film layer is formed on the surface of the silicon-based negative electrode active material, the silicon-based negative electrode active material in the negative electrode active layer can be effectively prevented from being directly contacted with electrolyte, the occurrence probability of side reaction is reduced, the SEI film formed by a battery core in the charge and discharge process is more stable and compact and does not thicken along with the increase of the cycle times, the compatibility of the battery negative electrode and the electrolyte is improved, and the cycle stability of the battery negative electrode is improved, so that the capacity retention rate and the cycle performance of the lithium ion battery are obviously improved.
Drawings
Fig. 1 is a graph showing the cycle capacity retention rate of lithium ion batteries prepared in example 1 and comparative examples 1 to 4 according to the present invention.
Detailed Description
The technical scheme of the invention is described in detail below with reference to specific embodiments and attached drawings. The examples described herein are specific embodiments of the present invention for illustrating the concept of the present invention; the description is intended to be illustrative and exemplary in nature and should not be construed as limiting the scope of the invention in its aspects. In addition to the embodiments described herein, those skilled in the art can adopt other obvious solutions based on the disclosure of the claims of the present application and the specification thereof, including those adopting any obvious substitutions and modifications to the embodiments described herein.
Example 1
The embodiment provides an adhesive for improving the electrical property of a silicon-based negative electrode, which comprises the following components in parts by mass:
15 parts of carboxymethyl cellulose;
12 parts of citric acid;
6 parts of sodium alginate;
12 parts of polystyrene butadiene copolymer;
3 parts of polyethylene glycol;
the balance of deionized water.
The embodiment also provides a lithium ion battery, which comprises a shell and a battery core positioned in the shell, wherein the battery core is formed by sequentially laminating and winding a battery anode, a diaphragm and a battery cathode.
The battery anode comprises an anode current collector and an anode active layer positioned on the surface of the anode current collector, and the preparation method comprises the following steps: uniformly mixing nano silicon, carbon black and the obtained adhesive according to the mass ratio of 95:2:3 to obtain negative electrode active slurry; and coating the negative electrode active slurry on the surface of a negative electrode current collector, rolling and drying, and then forming a negative electrode active layer on the surface of the negative electrode current collector, and then sequentially trimming, cutting and slitting to obtain the battery negative electrode.
The battery anode comprises an anode current collector and an anode active layer positioned on the surface of the anode current collector, and the preparation method comprises the following steps: ternary material LiNi of nickel cobalt lithium manganate 9 Co 0.5 Mn 0.5 O 2 Adding the conductive agent SuperP, the adhesive PVDF and the carbon nano tube into NMP according to the mass ratio of 97:1:1.3:0.7, and uniformly mixing to obtain anode active slurry; and coating the positive electrode active slurry on the surface of a positive electrode current collector, rolling and drying, and then, sequentially trimming, cutting and slitting to obtain the positive electrode of the battery.
And sequentially stacking the obtained battery anode, the PE diaphragm and the obtained battery cathode, winding to obtain a battery core, loading the battery core into a shell, injecting electrolyte into the shell, and packaging to obtain the lithium ion battery, wherein the electrolyte is a mixed solution (the volume ratio of EC, DEC and EMC is 1:1) of Ethylene Carbonate (EC)/diethyl carbonate (DEC)/Ethyl Methyl Carbonate (EMC) containing 1M LiPF 6.
Example 2
The embodiment provides an adhesive for improving the electrical property of a silicon-based negative electrode, which comprises the following components in parts by mass:
12 parts of carboxymethyl cellulose;
13 parts of citric acid;
sodium alginate 7 parts;
13 parts of polystyrene butadiene copolymer;
2 parts of polyvinyl alcohol;
the balance of deionized water.
The embodiment also provides a lithium ion battery, which comprises a shell and a battery core positioned in the shell, wherein the battery core is formed by sequentially laminating and winding a battery anode, a diaphragm and a battery cathode.
The battery anode comprises an anode current collector and an anode active layer positioned on the surface of the anode current collector, and the preparation method comprises the following steps: uniformly mixing the micrometer silicon, the carbon nano tube and the obtained adhesive according to the mass ratio of 94:3:3 to obtain negative electrode active slurry; and coating the negative electrode active slurry on the surface of a negative electrode current collector, rolling and drying, and then forming a negative electrode active layer on the surface of the negative electrode current collector, and then sequentially trimming, cutting and slitting to obtain the battery negative electrode.
The battery anode comprises an anode current collector and an anode active layer positioned on the surface of the anode current collector, and the preparation method comprises the following steps: ternary material LiNi of nickel cobalt lithium manganate 9 Co 0.5 Mn 0.5 O 2 Adding the conductive agent SuperP, the adhesive PVDF and the carbon nano tube into NMP according to the mass ratio of 97:1:1.3:0.7, and uniformly mixing to obtain anode active slurry; and coating the positive electrode active slurry on the surface of a positive electrode current collector, rolling and drying, and then, sequentially trimming, cutting and slitting to obtain the positive electrode of the battery.
And sequentially stacking the obtained battery anode, the PE diaphragm and the obtained battery cathode, winding to obtain a battery core, loading the battery core into a shell, injecting electrolyte into the shell, and packaging to obtain the lithium ion battery, wherein the electrolyte is a mixed solution (the volume ratio of EC, DEC and EMC is 1:1) of Ethylene Carbonate (EC)/diethyl carbonate (DEC)/Ethyl Methyl Carbonate (EMC) containing 1M LiPF 6.
Example 3
The embodiment provides an adhesive for improving the electrical property of a silicon-based negative electrode, which comprises the following components in parts by mass:
20 parts of hydroxypropyl methylcellulose;
10 parts of citric acid;
5 parts of sodium alginate;
14 parts of polystyrene butadiene copolymer;
4 parts of sodium dodecyl benzene sulfonate;
the balance of deionized water.
The embodiment also provides a lithium ion battery, which comprises a shell and a battery core positioned in the shell, wherein the battery core is formed by sequentially laminating and winding a battery anode, a diaphragm and a battery cathode.
The battery anode comprises an anode current collector and an anode active layer positioned on the surface of the anode current collector, and the preparation method comprises the following steps: uniformly mixing the silicon-oxygen composite material, the conductive graphite and the obtained adhesive according to the mass ratio of 95:3:2 to obtain negative electrode active slurry; and coating the negative electrode active slurry on the surface of a negative electrode current collector, rolling and drying, and then forming a negative electrode active layer on the surface of the negative electrode current collector, and then sequentially trimming, cutting and slitting to obtain the battery negative electrode.
The battery anode comprises an anode current collector and an anode active layer positioned on the surface of the anode current collector, and the preparation method comprises the following steps: ternary material LiNi of nickel cobalt lithium manganate 9 Co 0.5 Mn 0.5 O 2 Adding the conductive agent SuperP, the adhesive PVDF and the carbon nano tube into NMP according to the mass ratio of 97:1:1.3:0.7, and uniformly mixing to obtain anode active slurry; and coating the positive electrode active slurry on the surface of a positive electrode current collector, rolling and drying, and then, sequentially trimming, cutting and slitting to obtain the positive electrode of the battery.
And sequentially stacking the obtained battery anode, the PE diaphragm and the obtained battery cathode, winding to obtain a battery core, loading the battery core into a shell, injecting electrolyte into the shell, and packaging to obtain the lithium ion battery, wherein the electrolyte is a mixed solution (the volume ratio of EC, DEC and EMC is 1:1) of Ethylene Carbonate (EC)/diethyl carbonate (DEC)/Ethyl Methyl Carbonate (EMC) containing 1M LiPF 6.
Example 4
The embodiment provides an adhesive for improving the electrical property of a silicon-based negative electrode, which comprises the following components in parts by mass:
23 parts of carboxymethyl cellulose;
15 parts of citric acid;
8 parts of sodium alginate;
10 parts of polystyrene butadiene copolymer;
3 parts of stearic acid;
the balance of deionized water.
The embodiment also provides a lithium ion battery, which comprises a shell and a battery core positioned in the shell, wherein the battery core is formed by sequentially laminating and winding a battery anode, a diaphragm and a battery cathode.
The battery anode comprises an anode current collector and an anode active layer positioned on the surface of the anode current collector, and the preparation method comprises the following steps: uniformly mixing a silicon-carbon composite material, ketjen black and the obtained adhesive according to the mass ratio of 96:2:2 to obtain negative electrode active slurry; and coating the negative electrode active slurry on the surface of a negative electrode current collector, rolling and drying, and then forming a negative electrode active layer on the surface of the negative electrode current collector, and then sequentially trimming, cutting and slitting to obtain the battery negative electrode.
The battery anode comprises an anode current collector and an anode active layer positioned on the surface of the anode current collector, and the preparation method comprises the following steps: ternary material LiNi of nickel cobalt lithium manganate 9 Co 0.5 Mn 0.5 O 2 Adding the conductive agent SuperP, the adhesive PVDF and the carbon nano tube into NMP according to the mass ratio of 97:1:1.3:0.7, and uniformly mixing to obtain anode active slurry; and coating the positive electrode active slurry on the surface of a positive electrode current collector, rolling and drying, and then, sequentially trimming, cutting and slitting to obtain the positive electrode of the battery.
And sequentially stacking the obtained battery anode, the PE diaphragm and the obtained battery cathode, winding to obtain a battery core, loading the battery core into a shell, injecting electrolyte into the shell, and packaging to obtain the lithium ion battery, wherein the electrolyte is a mixed solution (the volume ratio of EC, DEC and EMC is 1:1) of Ethylene Carbonate (EC)/diethyl carbonate (DEC)/Ethyl Methyl Carbonate (EMC) containing 1M LiPF 6.
Example 5
The embodiment provides an adhesive for improving the electrical property of a silicon-based negative electrode, which comprises the following components in parts by mass:
26 parts of hydroxypropyl methyl cellulose;
14 parts of citric acid;
6 parts of sodium alginate;
15 parts of polystyrene butadiene copolymer;
5 parts of stearic acid;
the balance of deionized water.
The embodiment also provides a lithium ion battery, which comprises a shell and a battery core positioned in the shell, wherein the battery core is formed by sequentially laminating and winding a battery anode, a diaphragm and a battery cathode.
The battery anode comprises an anode current collector and an anode active layer positioned on the surface of the anode current collector, and the preparation method comprises the following steps: uniformly mixing nano silicon, graphene and the obtained adhesive according to the mass ratio of 97:1:2 to obtain negative electrode active slurry; and coating the negative electrode active slurry on the surface of a negative electrode current collector, rolling and drying, and then forming a negative electrode active layer on the surface of the negative electrode current collector, and then sequentially trimming, cutting and slitting to obtain the battery negative electrode.
The battery anode comprises an anode current collector and an anode active layer positioned on the surface of the anode current collector, and the preparation method comprises the following steps: ternary material LiNi of nickel cobalt lithium manganate 9 Co 0.5 Mn 0.5 O 2 Adding the conductive agent SuperP, the adhesive PVDF and the carbon nano tube into NMP according to the mass ratio of 97:1:1.3:0.7, and uniformly mixing to obtain anode active slurry; and coating the positive electrode active slurry on the surface of a positive electrode current collector, rolling and drying, and then, sequentially trimming, cutting and slitting to obtain the positive electrode of the battery.
And sequentially stacking the obtained battery anode, the PE diaphragm and the obtained battery cathode, winding to obtain a battery core, loading the battery core into a shell, injecting electrolyte into the shell, and packaging to obtain the lithium ion battery, wherein the electrolyte is a mixed solution (the volume ratio of EC, DEC and EMC is 1:1) of Ethylene Carbonate (EC)/diethyl carbonate (DEC)/Ethyl Methyl Carbonate (EMC) containing 1M LiPF 6.
Example 6
The present embodiment provides an adhesive differing from embodiment 1 in that the mass part of carboxymethyl cellulose added in the adhesive is adjusted to 9 parts, compared with embodiment 1, the mass part of carboxymethyl cellulose is reduced by 6 parts, and the reduced 6 parts are added to the mass parts of citric acid, sodium alginate, polystyrene butadiene copolymer, polyethylene glycol and deionized water in equal proportion so that the ratio of the mass parts between the other components except carboxymethyl cellulose is unchanged. The mass parts of the components in the regulated adhesive are as follows:
9 parts of carboxymethyl cellulose;
12.8 parts of citric acid;
6.4 parts of sodium alginate;
12.8 parts of polystyrene butadiene copolymer;
3.2 parts of polyethylene glycol;
the balance of deionized water.
Before adjustment, the mass part ratio of the citric acid, the sodium alginate, the polystyrene butadiene copolymer and the polyethylene glycol is 4:2:4:1, and after adjustment, the mass part ratio of the citric acid, the sodium alginate, the polystyrene butadiene copolymer and the polyethylene glycol is ensured to be 4:2:4:1.
The above adhesive was prepared into a negative electrode active slurry according to the ratio provided in example 1, which was coated on the surface of a negative electrode current collector, and rolled and dried to prepare a battery negative electrode. The fabricated battery negative electrode was assembled into a lithium ion battery according to the battery assembling method provided in example 1.
Example 7
The present embodiment provides an adhesive differing from embodiment 1 in that the mass part of carboxymethyl cellulose added in the adhesive is adjusted to 30 parts, in this embodiment, the mass part of carboxymethyl cellulose is increased by 15 parts, and the increased 15 parts are subtracted from the medium proportion of the mass parts of citric acid, sodium alginate, polystyrene butadiene copolymer, polyethylene glycol and deionized water, so that the proportion of the mass parts between the other components except carboxymethyl cellulose is unchanged. The mass parts of the components in the regulated adhesive are as follows:
30 parts of carboxymethyl cellulose;
9.88 parts of citric acid;
sodium alginate 4.94 parts;
9.88 parts of polystyrene butadiene copolymer;
polyethylene glycol 2.47 parts;
the balance of deionized water.
Before adjustment, the mass part ratio of the citric acid, the sodium alginate, the polystyrene butadiene copolymer and the polyethylene glycol is 4:2:4:1, and after adjustment, the mass part ratio of the citric acid, the sodium alginate, the polystyrene butadiene copolymer and the polyethylene glycol is ensured to be 4:2:4:1.
The above adhesive was prepared into a negative electrode active slurry according to the ratio provided in example 1, which was coated on the surface of a negative electrode current collector, and rolled and dried to prepare a battery negative electrode. The fabricated battery negative electrode was assembled into a lithium ion battery according to the battery assembling method provided in example 1.
Example 8
This example provides an adhesive differing from example 1 in that the mass part of citric acid added in the adhesive is adjusted to 8 parts, compared with example 1, the mass part of citric acid in this example is reduced by 4 parts, and the reduced 4 parts are added to the mass parts of carboxymethyl cellulose, sodium alginate, polystyrene butadiene copolymer, polyethylene glycol and deionized water in equal proportion so that the ratio of the mass parts between the other components except citric acid is unchanged. The mass parts of the components in the regulated adhesive are as follows:
15.70 parts of carboxymethyl cellulose;
8 parts of citric acid;
6.28 parts of sodium alginate;
12.56 parts of polystyrene butadiene copolymer;
3.14 parts of polyethylene glycol;
the balance of deionized water.
Before adjustment, the mass part ratio of the carboxymethyl cellulose, the sodium alginate, the polystyrene butadiene copolymer and the polyethylene glycol is 5:2:4:1, and after adjustment, the mass part ratio of the carboxymethyl cellulose, the sodium alginate, the polystyrene butadiene copolymer and the polyethylene glycol is ensured to be 5:2:4:1.
The above adhesive was prepared into a negative electrode active slurry according to the ratio provided in example 1, which was coated on the surface of a negative electrode current collector, and rolled and dried to prepare a battery negative electrode. The fabricated battery negative electrode was assembled into a lithium ion battery according to the battery assembling method provided in example 1.
Example 9
This example provides an adhesive differing from example 1 in that the mass part of citric acid added in the adhesive is adjusted to 20 parts, in this example, the mass part of citric acid is increased by 8 parts, and the increased 8 parts are subtracted from the mass part of carboxymethyl cellulose, sodium alginate, polystyrene butadiene copolymer, polyethylene glycol, and deionized water, etc., so that the ratio of the mass parts between the other components other than citric acid is unchanged. The mass parts of the components in the regulated adhesive are as follows:
13.65 parts of carboxymethyl cellulose;
20 parts of citric acid;
sodium alginate 5.46 parts;
10.92 parts of polystyrene butadiene copolymer;
polyethylene glycol 2.73 parts;
the balance of deionized water.
Before adjustment, the mass part ratio of the carboxymethyl cellulose, the sodium alginate, the polystyrene butadiene copolymer and the polyethylene glycol is 5:2:4:1, and after adjustment, the mass part ratio of the carboxymethyl cellulose, the sodium alginate, the polystyrene butadiene copolymer and the polyethylene glycol is ensured to be 5:2:4:1.
The above adhesive was prepared into a negative electrode active slurry according to the ratio provided in example 1, which was coated on the surface of a negative electrode current collector, and rolled and dried to prepare a battery negative electrode. The fabricated battery negative electrode was assembled into a lithium ion battery according to the battery assembling method provided in example 1.
Example 10
The present embodiment provides an adhesive differing from embodiment 1 in that the mass part of sodium alginate added in the adhesive is adjusted to 2 parts, compared with embodiment 1 in which the mass part of sodium alginate is reduced by 4 parts, the reduced 4 parts are added to the mass parts of carboxymethyl cellulose, citric acid, polystyrene butadiene copolymer, polyethylene glycol and deionized water in equal proportion, so that the ratio of the mass parts between the other components except sodium alginate is unchanged. The mass parts of the components in the regulated adhesive are as follows:
15.65 parts of carboxymethyl cellulose;
12.52 parts of citric acid;
2 parts of sodium alginate;
12.52 parts of polystyrene butadiene copolymer;
3.13 parts of polyethylene glycol;
the balance of deionized water.
Before adjustment, the mass part ratio of the carboxymethyl cellulose, the citric acid, the polystyrene butadiene copolymer and the polyethylene glycol is 5:4:4:1, and after adjustment, the mass part ratio of the carboxymethyl cellulose, the citric acid, the polystyrene butadiene copolymer and the polyethylene glycol is ensured to be 5:4:4:1.
The above adhesive was prepared into a negative electrode active slurry according to the ratio provided in example 1, which was coated on the surface of a negative electrode current collector, and rolled and dried to prepare a battery negative electrode. The fabricated battery negative electrode was assembled into a lithium ion battery according to the battery assembling method provided in example 1.
Example 11
The present embodiment provides an adhesive differing from embodiment 1 in that the mass part of sodium alginate added in the adhesive is adjusted to 12 parts, the mass part of sodium alginate in this embodiment is increased by 6 parts, and the increased 6 parts are subtracted from the mass parts of carboxymethyl cellulose, citric acid, polystyrene butadiene copolymer, polyethylene glycol and deionized water in a moderate proportion, so that the proportion of the mass parts between the other components except sodium alginate is unchanged. The mass parts of the components in the regulated adhesive are as follows:
14.05 parts of carboxymethyl cellulose;
20 parts of citric acid;
11.24 parts of sodium alginate;
11.24 parts of polystyrene butadiene copolymer;
polyethylene glycol 2.81 parts;
the balance of deionized water.
Before adjustment, the mass part ratio of the carboxymethyl cellulose, the citric acid, the polystyrene butadiene copolymer and the polyethylene glycol is 5:4:4:1, and after adjustment, the mass part ratio of the carboxymethyl cellulose, the citric acid, the polystyrene butadiene copolymer and the polyethylene glycol is ensured to be 5:4:4:1.
The above adhesive was prepared into a negative electrode active slurry according to the ratio provided in example 1, which was coated on the surface of a negative electrode current collector, and rolled and dried to prepare a battery negative electrode. The fabricated battery negative electrode was assembled into a lithium ion battery according to the battery assembling method provided in example 1.
Comparative example 1
This example provides an adhesive which differs from example 1 in that the carboxymethyl cellulose in the adhesive is omitted and 15 parts by weight of the carboxymethyl cellulose is added to 15 parts by weight of citric acid, sodium alginate, polystyrene butadiene copolymer, polyethylene glycol and deionized water so that the ratio of parts by weight between the other components except the carboxymethyl cellulose is unchanged. The mass parts of the components in the regulated adhesive are as follows:
14.12 parts of citric acid;
sodium alginate 7.06 parts;
14.12 parts of polystyrene butadiene copolymer;
3.53 parts of polyethylene glycol;
the balance of deionized water.
Before adjustment, the mass part ratio of the citric acid, the sodium alginate, the polystyrene butadiene copolymer and the polyethylene glycol is 4:2:4:1, and after adjustment, the mass part ratio of the citric acid, the sodium alginate, the polystyrene butadiene copolymer and the polyethylene glycol is ensured to be 4:2:4:1.
The above adhesive was prepared into a negative electrode active slurry according to the ratio provided in example 1, which was coated on the surface of a negative electrode current collector, and rolled and dried to prepare a battery negative electrode. The fabricated battery negative electrode was assembled into a lithium ion battery according to the battery assembling method provided in example 1.
Comparative example 2
This example provides an adhesive which differs from example 1 in that citric acid in the adhesive is omitted and 12 parts by weight of citric acid is added to 12 parts by weight of carboxymethyl cellulose, sodium alginate, polystyrene butadiene copolymer, polyethylene glycol and deionized water so that the ratio of parts by weight between the other components except citric acid is unchanged. The mass parts of the components in the regulated adhesive are as follows:
17.05 parts of carboxymethyl cellulose;
6.82 parts of sodium alginate;
13.64 parts of polystyrene butadiene copolymer;
3.41 parts of polyethylene glycol;
the balance of deionized water.
Before adjustment, the mass part ratio of the carboxymethyl cellulose, the sodium alginate, the polystyrene butadiene copolymer and the polyethylene glycol is 5:2:4:1, and after adjustment, the mass part ratio of the carboxymethyl cellulose, the sodium alginate, the polystyrene butadiene copolymer and the polyethylene glycol is ensured to be 5:2:4:1.
The above adhesive was prepared into a negative electrode active slurry according to the ratio provided in example 1, which was coated on the surface of a negative electrode current collector, and rolled and dried to prepare a battery negative electrode. The fabricated battery negative electrode was assembled into a lithium ion battery according to the battery assembling method provided in example 1.
Comparative example 3
This example provides an adhesive which is different from example 1 in that sodium alginate in the adhesive is omitted and 6 parts by weight of sodium alginate is added to 6 parts by weight of carboxymethyl cellulose, citric acid, polystyrene butadiene copolymer, polyethylene glycol and deionized water so that the ratio of parts by weight between the other components except sodium alginate is unchanged. The mass parts of the components in the regulated adhesive are as follows:
15.95 parts of carboxymethyl cellulose;
12.76 parts of citric acid;
12.76 parts of polystyrene butadiene copolymer;
3.19 parts of polyethylene glycol;
the balance of deionized water.
Before adjustment, the mass part ratio of the carboxymethyl cellulose, the citric acid, the polystyrene butadiene copolymer and the polyethylene glycol is 5:4:4:1, and after adjustment, the mass part ratio of the carboxymethyl cellulose, the citric acid, the polystyrene butadiene copolymer and the polyethylene glycol is ensured to be 5:4:4:1.
The above adhesive was prepared into a negative electrode active slurry according to the ratio provided in example 1, which was coated on the surface of a negative electrode current collector, and rolled and dried to prepare a battery negative electrode. The fabricated battery negative electrode was assembled into a lithium ion battery according to the battery assembling method provided in example 1.
Comparative example 4
This example provides an adhesive which differs from example 1 in that polyethylene glycol in the adhesive is omitted, and 3 parts by weight of polyethylene glycol is added to the parts by weight of carboxymethyl cellulose, citric acid, sodium alginate, polystyrene butadiene copolymer and deionized water in equal proportion, so that the proportion of parts by weight between the other components except polyethylene glycol is unchanged. The mass parts of the components in the regulated adhesive are as follows:
15.47 parts of carboxymethyl cellulose;
12.38 parts of citric acid;
6.19 parts of sodium alginate;
12.38 parts of polystyrene butadiene copolymer;
the balance of deionized water.
Before adjustment, the mass part ratio of the carboxymethyl cellulose, the citric acid, the sodium alginate and the polystyrene butadiene copolymer is 5:4:2:4, and after adjustment, the mass part ratio of the carboxymethyl cellulose, the citric acid, the sodium alginate and the polystyrene butadiene copolymer is 5:4:2:4.
The above adhesive was prepared into a negative electrode active slurry according to the ratio provided in example 1, which was coated on the surface of a negative electrode current collector, and rolled and dried to prepare a battery negative electrode. The fabricated battery negative electrode was assembled into a lithium ion battery according to the battery assembling method provided in example 1.
In order to show that the adhesive prepared by the invention can effectively solve the technical problems in the prior art, namely, how to effectively inhibit the volume expansion of the silicon-based material and reduce the falling risk of the negative electrode active layer and the negative electrode current collector. The present invention conducted the following tests on the battery cathodes/lithium ion batteries prepared in examples 1 to 11 and comparative examples 1 to 4:
(1) Interface performance test of negative electrode active layer and negative electrode current collector
Providing the battery cathodes prepared in examples 1-11 and comparative examples 1-4, winding the battery cathodes from one end to the other end of the battery cathode by using winding needles with different diameters (the diameters are respectively 1mm, 2mm, 3mm, 4mm and 5mm, the diameters of the winding needles used in the test process are gradually decreased, the winding needles with the diameter of 5mm begin to test), one side of the cathode current collector is close to the winding needle, one side of the cathode active layer is far away from the winding needle, bending deformation stress is generated after the battery cathode is wound, whether the wound battery cathode is cracked or fallen off due to the bending deformation stress is observed after the winding needles with different diameters are wound, and if the wound cathode active layer is cracked or fallen off due to the winding needles with the diameter, the winding needle diameter which does not crack or fall off the cathode active layer is recorded, and the smaller the winding needle diameter is indicates that the interface performance between the cathode active layer and the cathode current collector is better.
The minimum winding pin diameters of the negative electrode active layers of the negative electrodes of the batteries prepared in examples 1 to 11 and comparative examples 1 to 4 were measured according to the above-described test methods, and the test results are shown in table 1.
(2) Cycle performance test of lithium ion battery
Lithium ion batteries prepared in examples 1 to 11 and comparative examples 1 to 4 were provided, and the lithium ion batteries were subjected to a cyclic charge and discharge test at 25 ℃ in the following manner:
Firstly, discharging to 5mV at a discharge rate of 0.5C, then discharging to 5mV at a discharge rate of 0.05C, discharging to 5mV at a discharge rate of 0.02C, then discharging to 5mV at a discharge rate of 0.01C, and finally charging to 1.5V at a charge rate of 0.1C, namely, one charge-discharge cycle, and recording the charge specific capacity of the first cycle.
According to the charge-discharge cycle test, 200 charge-discharge cycles are performed, the charge specific capacity of the 200 th cycle is recorded, and a cycle charge specific capacity graph shown in fig. 1 is obtained, and as can be seen from fig. 1, the specific capacity retention rate of the lithium ion battery prepared in the embodiment 1 of the present invention is significantly higher than that of the comparative examples 1 to 4 as the cycle number increases.
Calculating a cyclic capacity retention rate according to the first cyclic charge specific capacity and the 200 th cyclic charge specific capacity, wherein the calculation formula is as follows:
。
the cycle capacity retention rates of the lithium ion batteries prepared in examples 1 to 11 and comparative examples 1 to 4 were calculated according to the above formulas, and the calculation results are shown in table 1.
(3) Thickness expansion rate test of battery cathode in full embedding state
Measuring initial thickness H of negative electrode of battery 0 (initial thickness of the negative electrode refers to the thickness of the negative electrode of the battery that was not used before the lithium ion battery was assembled), wherein the thickness of the negative electrode current collector is D 0 While ensuring that the thickness of the negative electrode current collector employed in all examples and comparative examples is D 0 ；
Discharging the assembled lithium ion battery to 5mV at 0.1C in a 25 ℃ environment, and then discharging to 5mV at 0.02C, so that the negative electrode of the battery is in a fully embedded state;
disassembling the lithium ion battery, and testing the thickness H of the battery cathode in the fully embedded state 1 The thickness of the negative electrode current collector in the fully embedded state is still D 0 ；
According to the initial thickness H of the battery cathode 0 Full ofThickness H of battery negative electrode in embedded state 1 The thickness of the negative electrode current collector is D 0 The thickness expansion rate (DeltaH%) of the battery cathode in the fully embedded state is calculated as follows:
。
the thickness expansion ratios of the negative electrodes of the batteries prepared in examples 1 to 11 and comparative examples 1 to 4 were calculated according to the above formulas, and the calculation results are shown in table 1.
TABLE 1 thickness expansion Rate of negative electrodes of batteries prepared in examples 1 to 11 and comparative examples 1 to 4
As can be seen from the data in table 1, the adhesive prepared in examples 1 to 11 provided by the invention can effectively inhibit the volume expansion of the silicon-based negative electrode active material, ensure good interface performance between the negative electrode active layer and the negative electrode current collector, and can still achieve a capacity retention rate of more than 90% after 200 cycles, thereby greatly improving the electrical performance of the lithium ion battery.
As can be seen from the test results of examples 1, 6 and 7, when the mass part of methylcellulose in the binder is in the range of 12-26 parts, a three-dimensional space network structure can be formed, and the silicon-based negative electrode active material embedded by citric acid is tightly locked inside the three-dimensional space network structure through ester group connection, so that the volume expansion of the silicon-based negative electrode active material is effectively inhibited, the prepared battery negative electrode and the negative electrode current collector have better adhesive property, and the assembled lithium ion battery has excellent cycle performance.
From the test results of examples 1, 8 and 9, it can be seen that when the mass part of citric acid in the adhesive is within the range of 10-15 parts, the citric acid can generate a covalent bond with the hydroxyl on the surface of the silicon-based negative electrode active material to realize chemical embedding of the silicon-based negative electrode active material, and can also generate an esterification reaction with methylcellulose to form an ester group connection, so that the silicon-based negative electrode active material and the methylcellulose form a three-dimensional network structure to be tightly connected, the prepared battery negative electrode and the negative electrode current collector have better adhesive property, and the assembled lithium ion battery has excellent cycle performance.
As can be seen from the test results of examples 1, 10 and 11, when the mass part of sodium alginate in the adhesive is in the range of 5-8 parts, the sodium alginate can be compounded with citric acid to embed the silicon-based negative electrode active material, and molecular bond acting force can be generated between the sodium alginate and methyl cellulose molecules, so that the silicon-based negative electrode active material and the three-dimensional network structure formed by the methyl cellulose are tightly connected, the prepared battery negative electrode and the negative electrode current collector have better bonding performance, and the assembled lithium ion battery has excellent cycle performance.
As can be seen from the test results of example 1 and comparative example 1, the volume expansion of the silicon-based negative electrode active material can be effectively suppressed by adding methylcellulose into the adhesive, and the battery negative electrode and the negative electrode current collector prepared by using the adhesive have better adhesion performance, and the assembled lithium ion battery has excellent cycle performance.
As can be seen from the test results of example 1 and comparative example 2, the volume expansion of the silicon-based negative electrode active material can be effectively suppressed by adding citric acid to the adhesive, and the battery negative electrode and the negative electrode current collector prepared by using the adhesive have better adhesion performance, and the assembled lithium ion battery has excellent cycle performance.
As can be seen from the test results of example 1 and comparative example 3, the volume expansion of the silicon-based negative electrode active material can be effectively inhibited by adding sodium alginate into the adhesive, the battery negative electrode prepared by using the sodium alginate has better adhesive property with the negative electrode current collector, and the assembled lithium ion battery has excellent cycle property.
As can be seen from the test results of example 1 and comparative example 4, the volume expansion of the silicon-based negative electrode active material can be effectively suppressed by adding polyethylene glycol to the adhesive, and the battery negative electrode and the negative electrode current collector prepared by using the polyethylene glycol have better adhesion performance, and the assembled lithium ion battery has excellent cycle performance.
The applicant declares that the above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that are easily conceivable within the technical scope of the present invention disclosed by the present invention fall within the scope of the present invention and the disclosure.
Claims (10)
1. The adhesive for improving the electrical property of the silicon-based negative electrode is characterized by comprising methyl cellulose, citric acid, sodium alginate, polystyrene butadiene copolymer, a film forming agent and deionized water.
2. The adhesive for improving electrical properties of a silicon-based negative electrode according to claim 1, wherein the adhesive comprises the following components in parts by mass, based on 100 parts by mass of the adhesive:
12-26 parts of methyl cellulose;
10-15 parts of citric acid;
5-8 parts of sodium alginate;
10-15 parts of polystyrene butadiene copolymer;
2-5 parts of film forming agent;
the balance of deionized water.
3. The binder for improving electrical properties of a silicon-based negative electrode according to claim 1, wherein the methylcellulose is carboxymethyl cellulose and/or hydroxypropyl methylcellulose.
4. The adhesive for improving electrical properties of a silicon-based negative electrode according to claim 1, wherein the film forming agent is any one or a combination of at least two of polyethylene glycol, polyvinyl alcohol, sodium dodecylbenzenesulfonate, and stearic acid.
5. The battery cathode is characterized by comprising a cathode current collector and a cathode active layer arranged on the surface of the cathode current collector;
the negative electrode active layer is prepared by the following method:
mixing a silicon-based anode active material, a conductive agent and the adhesive according to any one of claims 1 to 4 to obtain anode active slurry, coating the anode active slurry on the surface of the anode current collector, and rolling and drying to form the anode active layer.
6. The battery anode according to claim 5, wherein the mass ratio of the silicon-based anode active material, the conductive agent, and the binder is (94-97): 1-3): 2-3.
7. The battery anode according to claim 5, wherein the silicon-based anode active material is any one or a combination of at least two of micro silicon, nano silicon, silicon oxygen composite material, and silicon carbon composite material.
8. The battery anode according to claim 5, wherein the conductive agent is any one or a combination of at least two of carbon black, ketjen black, conductive graphite, carbon nanotubes, vapor deposited carbon nanofibers, graphene.
9. A lithium ion cell comprising a battery positive electrode, a separator, and a battery negative electrode according to any one of claims 5 to 8, stacked in this order.
10. A lithium ion battery comprising a housing and the lithium ion cell of claim 9 positioned within the housing, the housing having an electrolyte injected therein.
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| CN113363485A (en) * | 2021-05-28 | 2021-09-07 | 万向一二三股份公司 | Negative electrode slurry of lithium battery and preparation method thereof |
| CN113380985A (en) * | 2021-05-28 | 2021-09-10 | 万向一二三股份公司 | Method for improving stability of negative plate |
| CN116470054A (en) * | 2023-04-04 | 2023-07-21 | 华南师范大学 | Silicon negative electrode binder and preparation method and application thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105304858A (en) * | 2014-07-10 | 2016-02-03 | 宁德新能源科技有限公司 | Lithium ion battery, negative plate thereof and preparation method thereof |
| CN105958075A (en) * | 2016-06-28 | 2016-09-21 | 中国科学院广州能源研究所 | Multi-element functional modification polyvinyl alcohol-based lithium ion battery aqueous binder and application of the binder in electrochemical power storage device |
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