CN116314819A - Dispersing agent, positive electrode material containing dispersing agent and lithium ion battery - Google Patents
Dispersing agent, positive electrode material containing dispersing agent and lithium ion battery Download PDFInfo
- Publication number
- CN116314819A CN116314819A CN202310340603.5A CN202310340603A CN116314819A CN 116314819 A CN116314819 A CN 116314819A CN 202310340603 A CN202310340603 A CN 202310340603A CN 116314819 A CN116314819 A CN 116314819A
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- CN
- China
- Prior art keywords
- positive electrode
- dispersant
- active material
- olefin monomer
- copolymer
- Prior art date
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- 239000007774 positive electrode material Substances 0.000 title claims abstract description 118
- 239000002270 dispersing agent Substances 0.000 title claims abstract description 106
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims description 24
- 229910001416 lithium ion Inorganic materials 0.000 title claims description 24
- 229920001577 copolymer Polymers 0.000 claims abstract description 55
- 239000000178 monomer Substances 0.000 claims abstract description 35
- 150000001336 alkenes Chemical class 0.000 claims abstract description 31
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 claims abstract description 30
- 125000004432 carbon atom Chemical group C* 0.000 claims abstract description 13
- 239000006258 conductive agent Substances 0.000 claims description 61
- 239000011230 binding agent Substances 0.000 claims description 50
- 125000000217 alkyl group Chemical group 0.000 claims description 36
- 239000003792 electrolyte Substances 0.000 claims description 28
- 239000002904 solvent Substances 0.000 claims description 22
- -1 acrylic ester Chemical class 0.000 claims description 19
- 125000004435 hydrogen atom Chemical class [H]* 0.000 claims description 19
- 229910052736 halogen Inorganic materials 0.000 claims description 11
- 150000002367 halogens Chemical class 0.000 claims description 11
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical group C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 claims description 10
- 229910052739 hydrogen Inorganic materials 0.000 claims description 10
- 239000001257 hydrogen Substances 0.000 claims description 10
- 238000006467 substitution reaction Methods 0.000 claims description 7
- 150000002148 esters Chemical group 0.000 claims description 2
- 239000004973 liquid crystal related substance Substances 0.000 claims 2
- 238000000034 method Methods 0.000 description 47
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 28
- 239000002033 PVDF binder Substances 0.000 description 25
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 25
- 229910052782 aluminium Inorganic materials 0.000 description 24
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 24
- 239000010410 layer Substances 0.000 description 24
- 238000002156 mixing Methods 0.000 description 23
- 230000014759 maintenance of location Effects 0.000 description 20
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 19
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 18
- 239000011248 coating agent Substances 0.000 description 18
- 238000000576 coating method Methods 0.000 description 18
- 238000001035 drying Methods 0.000 description 18
- 239000000463 material Substances 0.000 description 16
- 238000003756 stirring Methods 0.000 description 16
- 230000000052 comparative effect Effects 0.000 description 15
- 229920001973 fluoroelastomer Polymers 0.000 description 15
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 14
- 239000011888 foil Substances 0.000 description 14
- 239000010405 anode material Substances 0.000 description 13
- 230000000694 effects Effects 0.000 description 13
- 238000003825 pressing Methods 0.000 description 13
- 238000012360 testing method Methods 0.000 description 13
- 239000004698 Polyethylene Substances 0.000 description 12
- 239000006229 carbon black Substances 0.000 description 12
- 239000000203 mixture Substances 0.000 description 12
- 229920000573 polyethylene Polymers 0.000 description 12
- 229920000642 polymer Polymers 0.000 description 12
- 238000002360 preparation method Methods 0.000 description 12
- 239000002562 thickening agent Substances 0.000 description 12
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 11
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 11
- 238000005520 cutting process Methods 0.000 description 11
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 11
- 239000003960 organic solvent Substances 0.000 description 11
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 9
- 239000001768 carboxy methyl cellulose Substances 0.000 description 9
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 8
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- 239000001267 polyvinylpyrrolidone Substances 0.000 description 8
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- 229910052744 lithium Inorganic materials 0.000 description 7
- 229910052751 metal Inorganic materials 0.000 description 7
- 239000002184 metal Substances 0.000 description 7
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- 150000003839 salts Chemical class 0.000 description 7
- 239000002002 slurry Substances 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 229910013870 LiPF 6 Inorganic materials 0.000 description 6
- 230000002776 aggregation Effects 0.000 description 6
- 239000006183 anode active material Substances 0.000 description 6
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- 239000007772 electrode material Substances 0.000 description 6
- 239000011267 electrode slurry Substances 0.000 description 6
- 239000011244 liquid electrolyte Substances 0.000 description 6
- 239000007773 negative electrode material Substances 0.000 description 6
- NIXOWILDQLNWCW-UHFFFAOYSA-M acrylate group Chemical group C(C=C)(=O)[O-] NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 5
- 238000005054 agglomeration Methods 0.000 description 5
- 239000011889 copper foil Substances 0.000 description 5
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- 239000010439 graphite Substances 0.000 description 5
- 238000006116 polymerization reaction Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- OZAIFHULBGXAKX-UHFFFAOYSA-N 2-(2-cyanopropan-2-yldiazenyl)-2-methylpropanenitrile Chemical compound N#CC(C)(C)N=NC(C)(C)C#N OZAIFHULBGXAKX-UHFFFAOYSA-N 0.000 description 4
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 4
- 229910000572 Lithium Nickel Cobalt Manganese Oxide (NCM) Inorganic materials 0.000 description 4
- 239000002202 Polyethylene glycol Substances 0.000 description 4
- FBDMTTNVIIVBKI-UHFFFAOYSA-N [O-2].[Mn+2].[Co+2].[Ni+2].[Li+] Chemical compound [O-2].[Mn+2].[Co+2].[Ni+2].[Li+] FBDMTTNVIIVBKI-UHFFFAOYSA-N 0.000 description 4
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- 229910052802 copper Inorganic materials 0.000 description 4
- 239000010949 copper Substances 0.000 description 4
- 125000004122 cyclic group Chemical group 0.000 description 4
- 238000007599 discharging Methods 0.000 description 4
- 239000006185 dispersion Substances 0.000 description 4
- GNTDGMZSJNCJKK-UHFFFAOYSA-N divanadium pentaoxide Chemical compound O=[V](=O)O[V](=O)=O GNTDGMZSJNCJKK-UHFFFAOYSA-N 0.000 description 4
- 230000014509 gene expression Effects 0.000 description 4
- 238000003384 imaging method Methods 0.000 description 4
- 229910003002 lithium salt Inorganic materials 0.000 description 4
- 159000000002 lithium salts Chemical class 0.000 description 4
- 239000012528 membrane Substances 0.000 description 4
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 4
- 239000004745 nonwoven fabric Substances 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 229920002239 polyacrylonitrile Polymers 0.000 description 4
- 229920001223 polyethylene glycol Polymers 0.000 description 4
- 239000005518 polymer electrolyte Substances 0.000 description 4
- 229920000098 polyolefin Polymers 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
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- 239000011029 spinel Substances 0.000 description 4
- 239000010935 stainless steel Substances 0.000 description 4
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical group O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- OQMIRQSWHKCKNJ-UHFFFAOYSA-N 1,1-difluoroethene;1,1,2,3,3,3-hexafluoroprop-1-ene Chemical group FC(F)=C.FC(F)=C(F)C(F)(F)F OQMIRQSWHKCKNJ-UHFFFAOYSA-N 0.000 description 3
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 3
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 3
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 3
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- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 3
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 description 3
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- 125000002573 ethenylidene group Chemical group [*]=C=C([H])[H] 0.000 description 3
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 3
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Images
Classifications
-
- 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
- H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F212/00—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
- C08F212/02—Monomers containing only one unsaturated aliphatic radical
- C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
- C08F212/06—Hydrocarbons
- C08F212/08—Styrene
-
- 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
- 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
- H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
-
- 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
- H01M2004/028—Positive 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 present invention relates to a dispersant for a positive electrode material, which comprises a copolymer formed by copolymerizing (a) a substituted or unsubstituted phenyl-substituted olefin monomer, (b) an ester-substituted olefin monomer, wherein the olefin monomers in (a) and (b) are each independently an olefin monomer containing 2 to 6 carbon atoms. The invention also relates to a positive electrode material containing the dispersing agent, a positive electrode plate containing or prepared from the positive electrode material, a secondary battery and an electric device.
Description
Technical Field
The invention relates to the technical field of batteries, in particular to a dispersing agent for a positive electrode material, which comprises a copolymer formed by copolymerizing (a) and (b), wherein the copolymer comprises (a) a substituted or unsubstituted phenyl substituted olefin monomer, (b) an ester substituted olefin monomer, and the olefin monomers in (a) and (b) are respectively and independently an olefin monomer containing 2-6 carbon atoms, a positive electrode material containing the dispersing agent, a positive electrode plate containing the dispersing agent or prepared from the positive electrode material, a secondary battery and an electric device.
Background
The lithium ion battery has the advantages of large specific energy, long cycle life, low self-discharge rate, no memory effect, environmental friendliness and the like, and has wide application in the fields of aviation, national defense, automobiles, 3C and the like. Along with the continuous development and progress of lithium ion batteries, the lithium ion batteries have higher requirements on the aspects of multiplying power, cycle capacity retention rate, energy density and the like. In addition to the effect of the positive electrode active material itself, the positive electrode material formulation also has a critical effect on the aspects of battery rate, cycle capacity retention, energy density, and the like. Therefore, optimizing the formulation of the positive electrode material from the material end has a critical effect on improving the performance of the lithium ion battery.
The lithium iron phosphate as the positive electrode active material has the advantages of low price, high safety, strong endurance capacity and the like. Because the lithium iron phosphate has lower conductivity, and a large amount of conductive agent (such as carbon black) is needed to be added to reduce the polarization of the positive electrode active substance of the battery in the battery charging and discharging environment in order to meet the requirement of a high-power chemical system on the performance of the battery core, higher discharge capacity is obtained, but the specific surface areas of the lithium iron phosphate material and the carbon black are larger, the phenomena of material agglomeration, slurry gel and the like are often caused by overlarge Van der Waals force in the homogenizing process, the obvious uneven dispersion of the conductive agent in the electrode slurry is caused, the stability and rheological property of the battery slurry are influenced, the gram capacity of the battery is reduced, the internal resistance of the battery is increased, and the storage and circulation performance of the battery are influenced.
CN 114843516A provides a dispersing agent for three-component lithium ion battery positive electrode materials, so that the positive electrode materials have higher solid content, lower viscosity and can be uniformly dispersed when using less solvent. CN 115490866A provides a dispersant for polycarboxylate lithium battery slurry, which improves the solid content and coating convenience of electrode active materials, and is beneficial to uniform dispersion of particles such as electrode active materials, conductive carbon and the like. CN 113540463B provides a dispersant comprising polyacrylonitrile and polystyrene, or a copolymer formed by copolymerizing acrylonitrile monomers and styrene monomers, which can reduce the phenomena of material gel and agglomeration in the process of homogenizing the cathode material, reduce the viscosity of the slurry, and improve the stability of the slurry; improving the dispersibility of the positive electrode material reduces the viscosity of the slurry.
Disclosure of Invention
In order to solve the problems, the compound provided by the invention can be used as a dispersing agent to obviously improve the uniform distribution of the conductive agent, thereby realizing the reduction of the resistance of the pole piece and the improvement of the retention rate of the circulation capacity of the battery.
In one aspect, the present invention provides a dispersant for a positive electrode material, the dispersant comprising a copolymer formed by copolymerizing (a) a substituted or unsubstituted phenyl-substituted olefin monomer, (b) an ester-substituted olefin monomer, wherein the olefin monomers in (a) and (b) are each independently an olefin monomer comprising 2 to 6 carbon atoms.
In one embodiment, (a) in the dispersant is a substituted or unsubstituted styrene monomer having the structure:
wherein each R is 2 Independently selected from hydrogen, C 1-6 Alkyl, halogen, p is selected from integers from 0 to 5,
In one embodiment, (b) in the dispersant is an acrylate monomer having the structure:
wherein R is 1 Selected from C 1-6 An alkyl group, a hydroxyl group,
each hydrogen atom in the moiety is optionally independently of the others C 1-4 Alkyl substitution.
In one embodiment, the copolymer of (a) and (b) comprises the following structural units:
wherein R is 1 Selected from C 1-6 An alkyl group;
each R 2 Independently selected from hydrogen, C 1-6 Alkyl, halogen;
p is selected from integers from 0 to 5;
the ratio of n to m is 1:3-3:1, preferably 1:1-1.1:1,
In one embodiment, the copolymer of (a) and (b) comprises the following structural units:
wherein R is 1 Selected from C 1-6 An alkyl group;
each R 2 Independently selected from hydrogen, C 1-6 Alkyl, halogen;
p is selected from integers from 0 to 5.
In another aspect, the present invention provides a positive electrode material comprising a positive electrode active material, a conductive agent, a binder, a solvent, and the dispersant of the above aspect.
In one embodiment, the content of the dispersant in the positive electrode material is 0.1 to 2 wt% based on the total weight of the positive electrode active material, the conductive agent, the binder and the dispersant.
In one embodiment, the content of the dispersant in the positive electrode material is 0.1 to 1 wt% based on the total weight of the positive electrode active material, the conductive agent, the binder and the dispersant.
In yet another aspect, the present invention provides a positive electrode sheet comprising or prepared from the positive electrode material of the present invention.
In still another aspect, the present invention provides a lithium ion secondary battery having a power generation element including: the positive pole piece of the invention; a negative electrode plate; an electrolyte; and a diaphragm.
In still another aspect, the present invention provides an electric device comprising the lithium ion secondary battery of the above aspect.
Drawings
Fig. 1 shows scanning electron microscope imaging of the positive electrode sheet in example 1.
Fig. 2 shows scanning electron microscope imaging of the positive electrode sheet in comparative example 1.
Fig. 3 shows scanning electron microscope imaging of the positive electrode sheet in comparative example 2.
Detailed Description
The present invention will be described in further detail below. Such description is for the purpose of illustration and not limitation. Other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure herein. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways. Various modifications and alterations may be made by those skilled in the art without departing from the spirit of the invention.
General definitions and terms
All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety, if not indicated otherwise.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In the event of a conflict, the definitions provided herein will control.
All percentages, parts, ratios, etc. are by weight unless otherwise specified.
When an amount, concentration, or other value or parameter is expressed as a range, preferred range, or upper preferable value limit, and a lower preferable value limit, this is to be understood as meaning any range that specifically recites any range by combining any pair of the upper range limit or preferred value with any lower range limit or preferred value, regardless of whether the range is specifically recited. Unless otherwise indicated, the numerical ranges set forth herein are intended to include the endpoints of the ranges and all integers and fractions within the range. The scope of the invention is not limited to the specific values recited when defining the scope. For example, "1-8" encompasses 1, 2, 3, 4, 5, 6, 7, 8 and any subrange comprised of any two values therein, e.g., 2-6, 3-5. Also e.g. C 1-6 Alkyl means alkyl having 1 to 6 carbon atoms, covering 1, 2, 3, 4, 5, 6, and any subrange of any two values, e.g. 1 to 6, 2 to 5, 3 to 4.
The terms "comprising," "including," "having," "containing," or "involving," and other variations thereof herein, are inclusive or open-ended and do not exclude additional unrecited elements or method steps. Those skilled in the art will appreciate that the terms such as "comprising" encompass "consisting of. The expression "consisting of" excludes any element, step or ingredient not specified. The expression "consisting essentially of …" means that the scope is limited to the specified elements, steps, or components, plus any elements, steps, or components that are optionally present that do not materially affect the basic and novel characteristics of the claimed subject matter. It should be understood that the expression "comprising" encompasses the expressions "consisting essentially of …" and "consisting of …".
The term "selected from …" means that one or more elements in the group listed below are independently selected and may include a combination of two or more elements.
The term "optional" or "optionally" as used herein means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.
Unless otherwise indicated, the terms "combination thereof" and "mixtures thereof" refer to multicomponent mixtures of the elements, e.g., two, three, four, and up to the maximum possible multicomponent mixtures.
Furthermore, the number of components or groups of components of the present invention not previously indicated is not limiting with respect to the number of occurrences (or existence) of components or groups of components. Thus, the singular forms of a component or a constituent should be interpreted to include one or at least one, and the plural unless the numerical value clearly indicates the singular.
The term "halogen" or "halo" is understood to mean fluorine (F), chlorine (C1), bromine (Br) or iodine (I), preferably fluorine, chlorine, bromine.
The term "alkyl" refers to a straight or branched saturated aliphatic hydrocarbon group consisting of carbon and hydrogen atoms, which is attached to the remainder of the molecule by a single bond. "alkyl" may have 1 to 6 carbon atoms, i.e. "C 1 -C 6 Alkyl "or" C 1-6 Alkyl ", e.g. C 1 -C 4 Alkyl, C 1 -C 3 Alkyl, C 1 -C 2 Alkyl, C 3 Alkyl, C 4 Alkyl, C 3 -C 6 An alkyl group. Non-limiting examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, 2-methylbutyl, 1-ethylpropyl, 1, 2-dimethylpropyl, neopentyl, 1-dimethylpropyl, 4-methylpentyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 2-ethylbutyl, 1-ethylbutyl, 3-dimethylbutyl, 2-dimethylbutyl, 1-dimethylbutyl, 2, 3-dimethylbutyl, 1, 3-dimethylbutyl, or 1, 2-dimethylbutyl, or isomers thereof.
The term "specific surface area" is used herein in the sense as commonly understood by a person skilled in the art, i.e. the total area per mass of material. The measurement may be performed according to methods and apparatuses conventional in the art, for example, a measurement of specific surface area using a multipoint BET method.
The term "structural unit" refers to a combination of atoms that constitute a polymer chain and that determine the structure of the polymer in such a way that the polymer is linked. For example, the structural units of the styrene-acrylate copolymer of the present application may be as follows.
The term "electrolyte" refers to a medium used in chemical batteries, electrolytic capacitors, and the like that can provide ions for the proper operation of the chemical batteries, electrolytic capacitors, and the like.
The term "secondary battery" refers to an electrochemical cell in which the electrochemical reaction is reversible, and also refers to a cell that is capable of being recharged or rechargeable for use over the life of the cell by repeated charging and discharging.
The term "lithium ion secondary battery" refers to a rechargeable battery type in which lithium ions move from an anode to a cathode during discharge and from the cathode to the anode during charge.
The term "anode" refers to an electrode in a secondary battery, which is oxidized during discharge and reduced during charge.
The term "cathode" refers to an electrode in a secondary battery, which undergoes reduction during discharge and oxidation during charge.
The term "current collector" refers to the base metal of the positive or negative electrode of the battery for attachment of the active material. For example, the positive electrode typically employs aluminum foil as a current collector, and the negative electrode typically employs copper foil as a current collector.
The term "SOC" refers to the state of charge of a battery, reflecting the remaining capacity of the battery, and is defined numerically as the ratio of the remaining capacity to the battery capacity, commonly expressed as a percentage.
The term "electric vehicle" refers to a vehicle powered by electricity, examples of which include, but are not limited to, electric Vehicles (EVs), hybrid Electric Vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and the like.
The term "electric two-wheeled vehicle" refers to two-wheeled vehicles powered by electricity, examples of which include, but are not limited to, E-bicycles and E-scooters.
Dispersing agent
In one aspect, the present invention provides a dispersant for a positive electrode material comprising a copolymer formed by copolymerizing (a) a substituted or unsubstituted phenyl-substituted olefin monomer and (b) an ester-substituted olefin monomer, wherein the olefin monomers in (a) and (b) are each independently an olefin monomer comprising 2 to 6 carbon atoms.
Optionally, the substituent R on the phenyl group in (a) 2 May be C 1-6 Alkyl or halogen.
In one embodiment, (a) in the dispersant is a substituted or unsubstituted styrene monomer having the structure:
wherein each R is 2 Independently selected from hydrogen, C 1-6 Alkyl, halogen, p is selected from integers from 0-5 (e.g., 0, 1, 2, 3, 4, 5),
The substituents on the phenyl groups may be C 1-6 Alkyl or halogen. Phenyl may also be unsubstituted, i.e., p is 0.
In one embodiment, the dispersant of (b) has the structure:
wherein R is 1 Selected from C 1-6 An alkyl group, a hydroxyl group,
each hydrogen atom in the moiety is optionally independently of the others C 1-4 Alkyl substitution. In the dispersing agent, the structural unit of the copolymer contains ester groups, so that the resistance of a pole piece can be reduced, the internal resistance of a battery can be reduced, and the retention rate of the circulating capacity of the battery can be improved.
It will be understood by those skilled in the art that the number of carbon atoms contained in the olefin monomer of (a) or (b) referred to herein refers to the number of carbon atoms contained in the olefin moiety other than a substituent (e.g., phenyl or ester group). For example, when (a) is a styrene monomer, the number of carbon atoms of the olefin monomer therein is 2. For another example, when (b) is an acrylate monomer, the number of carbon atoms of the olefin monomer therein is 2. When (a) 
Each hydrogen atom in the moiety is optionally independently of the others C 1-4 When alkyl is substituted, the conditions of (a) an olefin monomer having 2 to 6 carbon atoms are satisfied at the same time. Similarly, when +.>
Each hydrogen atom in the moiety is optionally independently of the others C 1-4 When alkyl is substituted, the conditions of (b) an olefin monomer having 2 to 6 carbon atoms are satisfied at the same time.
In one embodiment, the reaction temperature for the copolymerization of (a) and (b) is from 60 to 100 ℃.
In one embodiment, the reaction temperature for the copolymerization of (a) and (b) is from 70 to 90 ℃.
In one embodiment, the reaction time for the copolymerization of (a) and (b) is from 20 to 100 minutes.
In one embodiment, the reaction time for the copolymerization of (a) and (b) is from 30 to 90 minutes.
In one embodiment, the copolymer of (a) and (b) has a molecular weight of 10000 or less, and may be 10000, 9000, 8000, 7000, 6000, 5000, 4000, 3000, or the like, for example.
In one embodiment, the dispersant comprises a copolymer having a molar ratio of (a) to (b) of 1:3-3:1.
in one embodiment, the dispersant comprises a copolymer having a molar ratio of (a) to (b) of 1:1-1.1:1.
in one embodiment, the dispersant comprises a copolymer having a molar ratio of (a) to (b) of 1:1.
In one embodiment, the dispersant comprises a copolymer having a molar ratio of (a) to (b) of 1:1.1.
in one embodiment, the copolymer of (a) and (b) comprises the following structural units:
wherein R is 1 Selected from C 1-6 An alkyl group;
each R 2 Independently selected from hydrogen, C 1-6 Alkyl, halogen;
p is selected from integers from 0 to 5;
the ratio of n to m is 1:3-3:1, preferably 1:1-1.1:1,
In one embodiment, the copolymer of (a) and (b) comprises the following structural units:
wherein R is 1 Selected from C 1-6 An alkyl group;
each R 2 Independently selected from hydrogen, C 1-6 Alkyl, halogen;
p is selected from integers from 0 to 5.
In one embodiment, R 1 Selected from methyl, ethyl, isopropyl, n-butyl, isobutyl. In a preferred embodiment, R 1 Is methyl.
In one embodiment, R 2 Selected from hydrogen, methyl, ethyl, fluorine, chlorine or bromine. In a preferred embodiment, R 2 Is hydrogen.
In one embodiment, p is 0.
In one embodiment, the ratio of n to m is 1:1.
in one embodiment, the ratio of n to m is 1:1.1.
the invention also provides the use of the dispersant of the invention for preparing a positive electrode material or a lithium ion secondary battery.
In one embodiment, the content of the dispersant in the positive electrode material is 0.1 to 2 wt% based on the total weight of the positive electrode active material, the conductive agent, the binder and the dispersant.
In one embodiment, the content of the dispersant in the positive electrode material is 0.1 to 1 wt% based on the total weight of the positive electrode active material, the conductive agent, the binder and the dispersant.
In one embodiment, the content of the dispersant in the positive electrode material is 0.2 to 0.5 wt% based on the total weight of the positive electrode active material, the conductive agent, the binder and the dispersant.
The dispersant comprising the copolymer of (a) and (b), on the one hand, can prevent the agglomeration of the conductive agent by steric effect due to the aromatic group phenyl contained therein, and the electron cloud of benzene ring in the aromatic group can form pi-pi action with the surface of the conductive agent, further improving the dispersibility of the conductive agent. On the other hand, the acrylate group contained therein has good compatibility in N-methylpyrrolidone (NMP), which is a solvent commonly used for preparing electrode paste, due to its polarity. (a) The combination of the amphipathic nature of the copolymer of (b) can produce a synergistic effect, thereby greatly improving the dispersibility of the conductive agent in the electrode slurry, realizing the reduction of the resistance of the electrode plate, reducing the internal resistance of the battery and improving the retention rate of the circulating capacity of the battery.
Further, the copolymer of (a) and (b) has a molecular weight of 10000 or less, avoiding a large molecular weight (e.g., a molecular weight of 10 5 -10 6 ) In the using process of the dispersing agent, when the content is excessive, the internal resistance of the battery is increased, and the cycle performance of the battery is affected.
Positive electrode material
In another aspect, the present invention provides a positive electrode material comprising a positive electrode active material, a conductive agent, a binder, a solvent, and the dispersant of the present invention.
In one embodiment, the positive electrode material is used to prepare a lithium ion secondary battery.
In one embodiment, the positive electrode active material may be a composite metal oxide containing lithium and one or more of cobalt, manganese, and nickel. In one embodiment, the positive electrode active material is a single component. In another embodiment, the positive electrode active material is a mixture of the above composite metal oxides.
In one embodiment, the positive electrode active material includes lithium cobaltate, lithium manganate, lithium iron phosphate, and ternary materials (polymers of nickel cobalt manganese). In one embodiment, the positive electrode active material includes any one of lithium iron phosphate, lithium metal phosphate, vanadium pentoxide, lithium nickel cobalt alumina, lithium nickel cobalt manganese oxide, magnesium-rich lithium nickel cobalt manganese oxide, lithium manganese spinel, lithium nickel manganese spinel, or a combination thereof. In a preferred embodiment, the positive electrode active material is lithium iron phosphate.
In one embodiment, the conductive agent includes at least one of carbon black, carbon fiber, acetylene black, graphene, ketjen black, carbon nanotubes, and graphite. In a preferred embodiment, the conductive agent is carbon black, such as Super P.
In one embodiment, the binder comprises at least one of polyvinylidene fluoride (PVDF), sodium carboxymethyl cellulose (CMC), polyolefins (PP, PE, and other copolymers), modified styrene-butadiene rubber (SBR rubber), or a combination thereof. In a preferred embodiment, the binder is polyvinylidene fluoride.
In one embodiment, the positive electrode material can be prepared by mixing a positive electrode active material, a conductive agent, a binder and a dispersing agent according to a certain weight ratio, adding N-methylpyrrolidone as a solvent, and fully stirring and mixing.
In one embodiment, the positive electrode active material, the conductive agent, the binder and the dispersant are mixed in a weight ratio of (88-94): (4.7-5.1): (2.3-2.6): (0.1-2.1). In one embodiment, the mixture weight ratio of the positive electrode active material, the conductive agent, the binder, and the dispersant in the positive electrode material is 92:5:2.5:0.5. in one embodiment, the mixture weight ratio of the positive electrode active material, the conductive agent, the binder, and the dispersant in the positive electrode material is 92.37:5.02:2.51:0.1. in one embodiment, the mixture weight ratio of the positive electrode active material, the conductive agent, the binder, and the dispersant in the positive electrode material is 92.28:5.01:2.51:0.2. in one embodiment, the mixture weight ratio of the positive electrode active material, the conductive agent, the binder, and the dispersant in the positive electrode material is 92.18:5.01:2.51:0.3. in one embodiment, the mixture weight ratio of the positive electrode active material, the conductive agent, the binder, and the dispersant in the positive electrode material is 91.54:4.97:2.49:1. in one embodiment, the mixture weight ratio of the positive electrode active material, the conductive agent, the binder, and the dispersant in the positive electrode material is 90.61:4.93:2.46:2.
In one embodiment, the solvent in the positive electrode material includes an organic solvent or a non-organic solvent. In a preferred embodiment, the organic solvent comprises N-methylpyrrolidone, N-Dimethylformamide (DMF) and Dimethylsulfoxide (DMSO). In a more preferred embodiment, the organic solvent comprises N-methylpyrrolidone. In one embodiment, the non-organic solvent is deionized water.
In one embodiment, the dispersant may be contained in an amount of 0.1 to 2 wt% based on the total weight of the positive electrode active material, the conductive agent, the binder and the dispersant in the positive electrode material. In a preferred embodiment, the dispersant is present in an amount of 0.1% to 1% by weight based on the total weight of the positive electrode active material, the conductive agent, the binder and the dispersant in the positive electrode material. In a more preferred embodiment, the dispersant is present in an amount of 0.2% to 0.5% by weight based on the total weight of the positive electrode active material, the conductive agent, the binder and the dispersant in the positive electrode material. For example, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 2 wt%.
Positive electrode sheet and positive electrode current collector
In yet another aspect, the present invention provides a positive electrode sheet comprising or prepared from the positive electrode material of the present invention.
In one embodiment, the positive electrode sheet comprises a positive electrode current collector and a positive electrode material coated on the surface of the current collector.
In one embodiment, the positive electrode plate is made by coating a positive electrode material on a positive electrode current collector aluminum foil, and performing processes such as drying, cold pressing, cutting and the like.
In the present invention, the material constituting the positive electrode current collector is not particularly limited, and for example, a metal may be used. In particular, optional metals herein include, but are not limited to: aluminum, nickel, iron, stainless steel, titanium, ketone, combinations thereof, or the like. In addition to this, a clad material of nickel and aluminum, a thin layer material of copper and aluminum, a clad material of a combination thereof, or the like may be used. Further, the metal surface may be a foil formed by coating aluminum. In one embodiment, the positive electrode current collector comprises aluminum, nickel, iron, stainless steel, titanium, ketone, or a combination thereof. In one embodiment, the positive current collector comprises a coating material of nickel and aluminum, a thin layer material of copper and aluminum, or a combination thereof. In a specific embodiment, the positive current collector is aluminum foil.
The size of the positive electrode current collector is determined according to the use purpose of the battery. For example, if used for a large battery requiring high energy density, a large area current collector is used. The thickness of the current collector is not particularly limited and may be, for example, 1 to 100 μm, for example, 1 μm, 5 μm, 10 μm, 20 μm, 50 μm, 80 μm, 100 μm, etc.
Positive electrode active material layer
The positive electrode active material may be a composite metal oxide containing lithium and one or more of cobalt, manganese, and nickel. The positive electrode active material may be LiMn, for example 2 O 4 、LiCoO 2 、LiNiO 2 、Li(Ni-Mn-Co)O 2 And lithium-transition metal composite oxides such as those obtained by replacing a part of the transition metal with another element, lithium-transition metal phosphate compounds, lithium-transition metal sulfate compounds, and the like. From the viewpoints of capacity and power characteristics, a lithium-transition metal composite oxide can be used as the positive electrode active material. In some cases, 2 or more positive electrode active materials may be used in combination.
In one embodiment, the positive electrode active material includes any one of lithium iron phosphate, lithium metal phosphate, vanadium pentoxide, lithium nickel cobalt alumina, lithium nickel cobalt manganese oxide, magnesium-rich lithium nickel cobalt manganese oxide, lithium manganese spinel, lithium nickel manganese spinel, or a combination thereof. In a preferred embodiment, the positive electrode active material comprises lithium iron phosphate.
The positive electrode active material layer contains a positive electrode active material. The positive electrode active material layer is formed on the surface of the positive electrode current collector, and the shape and area thereof are not limited. The positive electrode active material layer may cover one side or both side surfaces of the positive electrode current collector. The average particle diameter of the positive electrode active material contained in the positive electrode active material layer is not particularly limited, and may be, for example, 1 to 100 μm, for example, 1 μm, 5 μm, 10 μm, 20 μm, 50 μm, 80 μm, 100 μm, or the like. Other additives (e.g., conductive agents, binders, etc.) may be further included in the positive electrode active material layer as needed to impart appropriate properties to the positive electrode.
Lithium ion secondary battery
In another aspect, the present invention provides a lithium ion secondary battery comprising the positive electrode sheet, the negative electrode sheet, the electrolyte and the separator of the present invention. In the present invention, the negative electrode sheet, the electrolyte, the separator, and other constituent members may be used without particular limitation.
In one embodiment, the negative electrode plate is prepared by mixing a negative electrode material, a conductive agent acetylene black, a thickener CMC and a binder SBR according to a mass ratio of 96.4:1:1.2:1.4, adding deionized water serving as a solvent, and fully stirring and mixing to obtain negative electrode slurry; the negative electrode slurry is uniformly coated on a negative electrode current collector copper foil, and the negative electrode current collector copper foil is prepared through the procedures of drying, cold pressing, slitting and the like.
In one embodiment, the electrolyte is prepared by mixing Ethylene Carbonate (EC), ethylmethyl carbonate (EMC), diethyl carbonate (DEC) in a volume ratio of 1:1:1 mixing to obtain an organic solvent, and drying the lithium salt LiPF 6 Is dissolved in the mixed organic solvent to prepare the water-soluble polymer with the preparation concentration of 1mol/L.
In one embodiment, the separator is a Polyethylene (PE) porous membrane having a thickness of 9-18 μm. In one embodiment, the separator is a PE porous membrane having a thickness of 11 μm. In one embodiment, the membrane air permeability is 180s/100mL to 380s/100mL. In one embodiment, the separator porosity is 30% to 50%.
In one embodiment, the prepared positive electrode plate, the prepared diaphragm and the prepared negative electrode plate are sequentially laminated, so that the diaphragm is positioned between the positive electrode plate and the negative electrode plate to play a role of isolation, then an aluminum plastic film is coated outside, the prepared electrolyte is injected after drying, and the soft package battery (namely the lithium ion secondary battery) with the capacity of 1Ah is finally prepared through procedures such as packaging, standing, formation and the like.
Negative electrode sheet and negative electrode current collector
In yet another aspect, the present invention is also directed to a negative electrode tab for a lithium ion secondary battery comprising a negative electrode current collector and a negative electrode material coated on the surface of the current collector. The negative electrode refers to an electrode having a low potential, from which electrons flow out from an external circuit during discharge.
In the present invention, the material constituting the negative electrode current collector is not particularly limited, and for example, a metal may be used. In particular, optional metals herein include, but are not limited to: aluminum, nickel, iron, stainless steel, titanium, copper, combinations thereof, or the like. When the negative electrode current collector is a combination of two or more metals, the negative electrode current collector can be in an alloy form, or can be in a cladding, plating or other form. From the viewpoints of electron conductivity and battery operating potential, the metal of the negative electrode current collector is preferably copper, aluminum or stainless steel. In a specific embodiment, the negative current collector is copper foil.
The size of the negative electrode current collector may be adjusted according to the actual use of the battery. For example, when used in a large battery requiring high energy density, a current collector having a large area may be used. The thickness of the negative electrode current collector is not limited, and may be, for example, 1 to 100 μm, for example, 1 μm, 5 μm, 10 μm, 20 μm, 50 μm, 80 μm, 100 μm, etc.
Negative electrode active material layer
The anode active material layer may contain an anode active material, which is generally a material capable of inserting or extracting lithium ions. The negative electrode active material that may be used herein may be a carbon material including, but not limited to, amorphous carbon coated graphite. Wherein, the graphite described herein may comprise: natural graphite, artificial graphite, modified graphite, silica composite artificial graphite, or combinations thereof. The negative electrode active material may be in the form of particles, powder, or the like, for example, amorphous carbon coated graphite particles.
The negative electrode active material layer is formed on the surface of the negative electrode current collector, and the shape and area thereof are not limited. The anode active material layer may cover one side or both side surfaces of the anode current collector. The thickness of the anode active material layer is not particularly limited, and may be, for example, 1 to 100 μm, for example, 1 μm, 5 μm, 10 μm, 20 μm, 50 μm, 80 μm, 100 μm, or the like. Other additives (e.g., a conductive agent, a thickener, a binder, etc.) may be further included in the anode active material layer as needed to impart appropriate properties to the anode.
Conductive agent
The conductive agent refers to an additive added to improve the conductivity of the electrode active material layer. When the conductive agent is contained in the electrode active material layer, an electronic network inside the active material layer can be efficiently formed, and the power characteristics of the battery can be facilitated. Conductive agents useful herein include, but are not limited to: carbon black, carbon fiber, acetylene black, graphene, ketjen black, carbon nanotubes and graphite, preferably carbon black. These conductive agents may be used alone or in combination of two or more. In one embodiment, the conductive agent is carbon black.
Thickening agent
When a binder for forming an aqueous binder system is used, the binder may be used in combination with a thickener in order to improve coatability, which contributes to obtaining a good coating effect during the preparation.
The thickener can improve the viscosity of the anode slurry, which helps to improve the coatability of the slurry. Optional thickeners herein include, but are not limited to: polyvinyl alcohol and modified products thereof, starch and modified products thereof (oxidized starch, phosphated starch, cationized starch, etc.), cellulose derivatives (carboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, salts thereof, etc.), polyvinylpyrrolidone, polyacrylic acid (salts), polyethylene glycol, copolymers of (meth) acrylamide and/or (meth) acrylic acid salt [ (meth) acrylamide polymer, (meth) acrylamide- (meth) acrylic acid salt copolymer, (meth) alkyl (carbon number 1-4) acrylate- (meth) acrylic acid salt copolymer, etc. ], styrene-maleate copolymer, mannich modified products of polyacrylamide, formaldehyde condensation resins (urea-formaldehyde resin, melamine-formaldehyde resin, etc.), water-soluble polymers such as polyamide polyamine or dialkylamine-epichlorohydrin copolymer, polyethyleneimine, casein, soy protein, synthetic protein, and galactomannan derivatives, etc. These thickeners may be used alone or in combination of two or more.
The thickener may preferably include: polyvinyl alcohol and its modified products, starch and its modified products, cellulose derivatives (carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, salts thereof, etc.), polyvinylpyrrolidone, polyacrylic acid (salts) or polyethylene glycol or combinations thereof, preferably sodium carboxymethyl cellulose. When styrene-butadiene rubber is used as the binder, these thickeners can be combined therewith to obtain a good bonding effect. In a preferred embodiment, styrene-butadiene rubber is used as the binder and carboxymethyl cellulose (salt) is used as the thickener. In a more preferred embodiment, styrene-butadiene rubber is used as the binder and sodium carboxymethyl cellulose is used as the thickener.
Adhesive agent
The binder is used to provide a bonding effect, and helps to obtain good adhesion inside the electrode active material layer and between the electrode active material layer and the electrode current collector. Binders useful herein include, but are not limited to: polyethylene, polypropylene, polyethylene terephthalate (PET), polyether nitrile, polyacrylonitrile, polyimide, polyamide, cellulose, carboxymethyl cellulose (CMC), and salts thereof, ethylene-vinyl acetate copolymer, polyvinyl chloride, styrene Butadiene Rubber (SBR), isoprene rubber, butadiene rubber, ethylene-propylene-diene copolymer, styrene-butadiene-styrene block copolymer and its hydrogenated product, thermoplastic polymer such as styrene-isoprene-styrene block copolymer and its hydrogenated product, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), ethylene-tetrafluoroethylene copolymer (ETFE), polychloroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), fluorocarbon resin such as polyvinyl fluoride (PVF), vinylidene fluoride-hexafluoropropylene-based fluororubber (VDF-HFP-based fluororubber), vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene-based fluororubber (VDF-HFP-TFE-based fluororubber), vinylidene fluoride-pentafluoropropylene-fluororubber (VDF-p-based fluororubber), vinylidene fluoride-hexafluoropropylene-based fluororubber (VDF-pff-p-based fluororubber), vinylidene fluoride-hexafluoropropylene-based fluororubber (pff-p-based fluororubber), and the like, vinylidene fluoride-based fluororubbers such as vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene-based fluororubbers (VDF-PFMVE-TFE-based fluororubbers) and vinylidene fluoride-chlorotrifluoroethylene-based fluororubbers (VDF-CTFE-based fluororubbers). These binders may be used alone or in combination of two or more.
Diaphragm
The separator has a function of retaining an electrolyte to ensure lithium ion conductivity between the positive electrode and the negative electrode, and a function as a partition wall between the positive electrode and the negative electrode. The form of the separator may be a porous sheet separator made of a polymer and/or a fiber, a nonwoven fabric separator, or the like.
As the separator of the porous sheet formed of the polymer and/or the fiber, a microporous (microporous membrane) may be used. Specifically, a microporous (microporous membrane) separator formed of: polyolefin such as Polyethylene (PE) and polypropylene (PP); a laminate obtained by laminating a plurality of the above-mentioned polyolefins (for example, a laminate having a 3-layer structure of PP/PE/PP), a hydrocarbon resin such as polyimide, aramid, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), or glass fiber, and the like. The thickness of the separator of the porous sheet is not limited. The nonwoven fabric separator may be made of cotton, rayon, acetate, nylon, polyester, polyolefin (such as PP, PE, etc.), polyimide, aramid, etc. alone or in combination. The bulk density of the nonwoven fabric is not particularly limited as long as sufficient battery characteristics can be obtained by the impregnated electrolyte. Therefore, the thickness of the nonwoven fabric separator may be the same as that of the electrolyte layer. In a preferred embodiment, the separator is an 11 μm thick polyethylene porous membrane.
Electrolyte solution
The electrolyte is used for transporting ions and conducting current between the anode and the cathode. The electrolyte is not particularly limited herein. A liquid electrolyte or a gel polymer electrolyte may be used.
The liquid electrolyte has a function as a carrier of lithium ions. The liquid electrolyte may comprise: a solvent (e.g., an organic solvent, which may act as a plasticizer), a lithium salt as a supporting salt dissolved in the solvent, and other optional additives. Organic solvents useful in the liquid electrolyte include, but are not limited to: carbonates such as Ethylene Carbonate (EC), ethylmethyl carbonate (EMC), propylene Carbonate (PC), dimethyl carbonate (DMC), and diethyl carbonate (DEC) are preferably mixed solvents of Ethylene Carbonate (EC), ethylmethyl carbonate (EMC), and diethyl carbonate (DEC). Lithium salts useful in the electrolyte include, but are not limited to: li (CF) 3 SO 2 ) 2 N、Li(C 2 F 5 SO 2 ) 2 N、LiPF 6 、LiBF 4 、LiClO 4 、LiAsF 6 、LiTaF 6 、LiCF 3 SO 3 Such as a compound that can be added to the active material layer of the electrode, preferably LiPF 6 . In a preferred embodiment, the electrolyte is a liquid electrolyte comprising: ethylene Carbonate (EC), ethylmethyl carbonate (EMC), diethyl carbonate (DEC) and LiPF 6 。
By using the gel polymer electrolyte, stabilization of the inter-electrode distance can be achieved, occurrence of polarization can be suppressed, and durability (cycle characteristics) can be improved. The gel polymer electrolyte may be obtained according to the following: the above-mentioned liquid electrolyte is injected into a matrix polymer (main polymer) containing an ion-conductive polymer. When a gel polymer electrolyte is used as the electrolyte, the electrolyte is no longer flowable and the ionic conductivity between the layers is easily blocked. Ion-conducting polymers of the matrix polymer (host polymer) include, but are not limited to: polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG), polyacrylonitrile (PAN), polyvinylidene fluoride-hexafluoropropylene (PVDF-HEP), polymethyl methacrylate (PMMA), copolymers thereof, and the like. The matrix polymer of the gel electrolyte can exhibit excellent mechanical strength by forming a crosslinked structure. In order to form the crosslinked structure, a polymerization treatment such as thermal polymerization, ultraviolet polymerization, radiation polymerization, electron beam polymerization, or the like may be performed on the polymerizable polymer for forming a polyelectrolyte (for example, PEO or PPO) using an appropriate polymerization initiator.
Battery performance test
Herein, the battery performance may be tested by the following method.
(1) Cycle capacity retention test
At 25 ℃, the cycle is carried out in a charge-discharge system of 0.21A/g (calculated by the mass of the anode material) and 2.5-3.65V. After cycling to 500 weeks, dividing the discharge capacity of the battery at the moment by the discharge capacity of the first cycle, namely the 500-cycle capacity retention rate of the battery.
(2) Pole piece resistance test
The positive electrode sheet was tested using a Hitachi diaphragm resistance meter RM 9003.
(3) Direct Current Resistance (DCR) test
And (3) discharging the battery to 50% SOC (state of charge) at a specified temperature, regulating the current to 4C, maintaining for 30s, and detecting the difference between the updated stable voltage and the original platform voltage, wherein the ratio of the value to the 3C current value is the direct current resistance of the battery. The DCR test result performed after the first full charge of the battery is the initial DCR of the battery.
In one embodiment, the secondary battery of the present invention has a cycle capacity retention rate of 80 to 90% after the above 500-week charge-discharge cycle. In a preferred embodiment, the secondary battery of the present invention has a cycle capacity retention rate of 80.6 to 89.5% after the above 500-week charge-discharge cycle. For example 80%, 80.68%, 81%, 81.16%, 83%, 83.08%, 84%, 84.52%, 85%, 85.17%, 86%, 89%, 89.39%.
In one embodiment, the positive electrode sheet of the present invention has a resistivity of 20 to 38Ω·cm. In a preferred embodiment, the positive electrode sheet of the present invention has a resistivity of 20.1 to 37.6Ω·cm. For example, 20Ω·cm, 20.1 Ω·cm, 22Ω·cm, 25Ω·cm, 28Ω·cm, 28.9Ω·cm, 30Ω·cm, 30.1 Ω·cm, 32Ω·cm, 32.3 Ω·cm, 34 Ω·cm, 34.1 Ω·cm, 37Ω·cm, 37.6 Ω·cm.
In one embodiment, the secondary battery of the present invention has an initial direct current resistance of 100 to 132mΩ. In a preferred embodiment, the secondary battery of the present invention has an initial direct current resistance of 100.7 to 131.5mΩ. For example, 100mΩ, 100.736mΩ, 105mΩ, 106.237mΩ, 110mΩ, 110.769mΩ, 114mΩ, 114.269mΩ, 120mΩ, 122.402mΩ, 130mΩ, 131.365mΩ, 132mΩ.
Electric device
In one aspect, the present invention provides an electric device characterized in that the electric device comprises the lithium ion secondary battery of the present invention.
Examples of electric devices include, but are not limited to, electric vehicles, electric two-wheeled vehicles, and electric storage systems, or combinations thereof, and plug-in hybrid electric vehicles, or combinations thereof.
Advantageous effects
On one hand, the dispersing agent containing the copolymer of (a) and (b) provided by the invention can prevent the aggregation of the conductive agent through steric hindrance effect due to the aromatic group contained therein, and the electron cloud of the benzene ring in the aromatic group can form pi-pi action with the surface of the conductive agent, so that the dispersibility of the conductive agent is further improved. On the other hand, the acrylate group contained therein has good compatibility in N-methylpyrrolidone (NMP), which is a solvent commonly used for preparing electrode paste, due to its polarity. The dispersing agent containing the copolymer of (a) and (b) provided by the invention, wherein the styrene end is taken as an anchoring group and can be conjugated with a lithium iron phosphate coated carbon layer and a carbon black conductive agent; the acrylate end has good combination effect with NMP, so that stable dispersion state can be formed. In particular, when the carbon black content is 3% or more, the use of the copolymer of (a) and (b) (for example, a styrene-acrylate copolymer) as a dispersant can greatly improve the dispersion state of the carbon black. (a) The combination of such amphiphilic properties with the copolymer of (b) (e.g., styrene-acrylate copolymer) can produce a synergistic effect, thereby significantly improving the uniform distribution of the conductive agent, achieving a reduction in pole piece resistance, and an increase in battery cycling capacity retention. Further, the copolymer of (a) and (b) has a molecular weight of 10000 or less, avoiding a large molecular weight (e.g., a molecular weight of 10 5 -10 6 ) In the using process of the dispersing agent, when the content is excessive, the internal resistance of the battery is increased, and the cycle performance of the battery is affected.
Examples
It should be noted that the following examples are only examples for clearly illustrating the technical solution of the present invention, and are not limiting. Other variations or modifications of the above description will be apparent to those of ordinary skill in the art, and it is not necessary or exhaustive of all embodiments, and obvious variations or modifications of the invention are intended to be within the scope of the invention.
The instrumentation and reagent materials used herein are commercially available unless otherwise indicated.
Instrument for measuring and controlling the intensity of light
And a charge-discharge machine: purchased from Cheng Hong (BTS 0510C 80-HP);
resistance meter: hitachi diaphragm resistance meter RM9003.
Scanning electron microscope: zeiss Sigma500 type field emission scanning electron microscope.
Material
Reagents used herein, such as ethylene carbonate, ethylmethyl carbonate, diethyl carbonate and LiPF 6 And purchased from Shanghai national medicine or Sigma-Aldrich company.
The structure of the compounds was determined by Nuclear Magnetic Resonance (NMR) and liquid chromatography-mass spectrometry (HPLC-MS).
Synthetic examples
Preparation of styrene-acrylate copolymers
0.3g of Azobisisobutyronitrile (AIBN) was weighed into a dry three-necked flask equipped with a stirring magnet and a reflux condenser, 20ml of styrene was added, stirring was started at a water bath temperature of 70-90℃at a stirring speed of 100-200rpm to sufficiently dissolve it, and then 10g of methyl acrylate was slowly added thereto for a reaction time of 30-90min. Adding polymerization inhibitor, after finishing the reaction, putting the obtained product into a 60 ℃ oven for baking and drying, and using the obtained styrene-acrylic ester copolymer as a dispersing agent.
Preparation example
Preparation of positive electrode plate
Mixing lithium iron phosphate anode active material, conductive agent Super P, binder polyvinylidene fluoride (PVDF) and styrene-acrylic ester copolymer dispersing agent according to a certain weight ratio, adding solvent N-methyl pyrrolidone (NMP), and fully stirring and mixing to obtain anode material; and uniformly coating the anode material on an anode current collector aluminum foil, and performing procedures such as drying, cold pressing, cutting and the like to prepare the anode plate.
Preparation of negative electrode plate
The cathode material, the conductive agent acetylene black, the thickener CMC and the binder SBR are mixed according to the weight ratio of 96.4:1:1 2:1.4, mixing, adding deionized water serving as a solvent, and fully stirring and mixing to obtain negative electrode slurry; and uniformly coating the negative electrode slurry on a negative electrode current collector copper foil, and performing procedures such as drying, cold pressing, slitting and the like to prepare the negative electrode plate.
Preparation of electrolyte
Ethylene Carbonate (EC), methyl ethyl carbonate (EMC) and diethyl carbonate (DEC) are mixed according to the volume ratio of 1:1:1, mixing to obtain an organic solvent, and then drying the lithium salt LiPF 6 Dissolving in the mixed organic solvent to prepare electrolyte with the concentration of 1 mol/L.
Preparation of separator
A separator having a thickness of 9 μm to 18 μm, an air permeability of 180s/100mL to 380s/100mL, and a porosity of 30% to 50% was selected for the preparation of a secondary battery. For example, in this example, a Polyethylene (PE) porous film having a thickness of 11 μm was used as the separator.
Preparation of secondary battery
And laminating the prepared positive pole piece, the diaphragm and the negative pole piece in sequence, so that the diaphragm is positioned between the positive pole piece and the negative pole piece to play a role in isolation. And then coating an aluminum plastic film, drying, injecting the prepared electrolyte, and finally preparing the soft-packaged battery (namely the lithium ion secondary battery) with the capacity of 1Ah through the procedures of packaging, standing, forming and the like.
The secondary batteries of examples 1 to 6 were prepared by adjusting the weight ratio of the styrene-acrylate copolymer as the dispersant according to the above-described method. According to the above method, comparative example 1 was prepared using polyvinylpyrrolidone (PVP) as a dispersant in place of the styrene-acrylate copolymer dispersant. Comparative example 2 was prepared according to the above method, removing the dispersant used therein. According to the above method, comparative example 3 was prepared using polystyrene as a dispersant instead of the styrene-acrylate copolymer dispersant. The preparation method comprises the following specific preparation steps.
Example 1
The lithium iron phosphate positive electrode active material, a conductive agent Super P, a binder polyvinylidene fluoride (PVDF) and a styrene-acrylic ester copolymer dispersing agent are mixed according to the weight ratio of 92:5:2.5:0.5, adding solvent N-methyl pyrrolidone (NMP), and fully stirring and mixing to obtain a positive electrode material; and uniformly coating the anode material on an anode current collector aluminum foil, and performing procedures such as drying, cold pressing, cutting and the like to prepare the anode plate. And the prepared positive electrode plate, the negative electrode plate prepared by the method, the diaphragm and the electrolyte are together used for preparing the secondary battery according to the method.
Example 2
The lithium iron phosphate positive electrode active material, a conductive agent Super P, a binder polyvinylidene fluoride (PVDF) and a styrene-acrylic ester copolymer dispersing agent are mixed according to the weight ratio of 92.37:5.02:2.51:0.1, adding solvent N-methyl pyrrolidone (NMP), and fully stirring and mixing to obtain a positive electrode material; and uniformly coating the anode material on an anode current collector aluminum foil, and performing procedures such as drying, cold pressing, cutting and the like to prepare the anode plate. And the prepared positive electrode plate, the negative electrode plate prepared by the method, the diaphragm and the electrolyte are together used for preparing the secondary battery according to the method.
Example 3
The lithium iron phosphate positive electrode active material, a conductive agent Super P, a binder polyvinylidene fluoride (PVDF) and a styrene-acrylic ester copolymer dispersing agent are mixed according to the weight ratio of 92.28:5.01:2.51:0.2, adding solvent N-methyl pyrrolidone (NMP), and fully stirring and mixing to obtain a positive electrode material; and uniformly coating the anode material on an anode current collector aluminum foil, and performing procedures such as drying, cold pressing, cutting and the like to prepare the anode plate. And the prepared positive electrode plate, the negative electrode plate prepared by the method, the diaphragm and the electrolyte are together used for preparing the secondary battery according to the method.
Example 4
The lithium iron phosphate positive electrode active material, a conductive agent Super P, a binder polyvinylidene fluoride (PVDF) and a styrene-acrylic ester copolymer dispersing agent are mixed according to the weight ratio of 92.18:5.01:2.51:0.3, adding solvent N-methyl pyrrolidone (NMP), and fully stirring and mixing to obtain a positive electrode material; and uniformly coating the anode material on an anode current collector aluminum foil, and performing procedures such as drying, cold pressing, cutting and the like to prepare the anode plate. And the prepared positive electrode plate, the negative electrode plate prepared by the method, the diaphragm and the electrolyte are together used for preparing the secondary battery according to the method.
Example 5
The lithium iron phosphate positive electrode active material, a conductive agent Super P, a binder polyvinylidene fluoride (PVDF) and a styrene-acrylic ester copolymer dispersing agent are mixed according to the weight ratio of 91.54:4.97:2.49:1, mixing, adding solvent N-methyl pyrrolidone (NMP), and fully stirring and mixing to obtain a positive electrode material; and uniformly coating the anode material on an anode current collector aluminum foil, and performing procedures such as drying, cold pressing, cutting and the like to prepare the anode plate. And the prepared positive electrode plate, the negative electrode plate prepared by the method, the diaphragm and the electrolyte are together used for preparing the secondary battery according to the method.
Example 6
The lithium iron phosphate positive electrode active material, a conductive agent Super P, a binder polyvinylidene fluoride (PVDF) and a styrene-acrylic ester copolymer dispersing agent are mixed according to the weight ratio of 90.61:4.93:2.46:2, mixing, adding solvent N-methyl pyrrolidone (NMP), and fully stirring and mixing to obtain a positive electrode material; and uniformly coating the anode material on an anode current collector aluminum foil, and performing procedures such as drying, cold pressing, cutting and the like to prepare the anode plate. And the prepared positive electrode plate, the negative electrode plate prepared by the method, the diaphragm and the electrolyte are together used for preparing the secondary battery according to the method.
Comparative example 1
The lithium iron phosphate positive electrode active material, a conductive agent Super P, a binder polyvinylidene fluoride (PVDF) and a polyvinylpyrrolidone (PVP) dispersing agent are mixed according to the weight ratio of 92:5:2.5:0.5, adding solvent N-methyl pyrrolidone (NMP), and fully stirring and mixing to obtain a positive electrode material; and uniformly coating the anode material on an anode current collector aluminum foil, and performing procedures such as drying, cold pressing, cutting and the like to prepare the anode plate. And the prepared positive electrode plate, the negative electrode plate prepared by the method, the diaphragm and the electrolyte are together used for preparing the secondary battery according to the method.
Comparative example 2
The lithium iron phosphate positive electrode active material, a conductive agent Super P and a binder polyvinylidene fluoride (PVDF) are mixed according to the weight ratio of 92:5:2.5, mixing, adding solvent N-methyl pyrrolidone (NMP), and fully stirring and mixing to obtain a positive electrode material; and uniformly coating the anode material on an anode current collector aluminum foil, and performing procedures such as drying, cold pressing, cutting and the like to prepare the anode plate. And the prepared positive electrode plate, the negative electrode plate prepared by the method, the diaphragm and the electrolyte are together used for preparing the secondary battery according to the method.
Comparative example 3
The lithium iron phosphate positive electrode active material, a conductive agent Super P, a binder polyvinylidene fluoride (PVDF) and a Polystyrene (PS) dispersing agent are mixed according to the weight ratio of 92:5:2.5:0.5, adding solvent N-methyl pyrrolidone (NMP), and fully stirring and mixing to obtain a positive electrode material; and uniformly coating the anode material on an anode current collector aluminum foil, and performing procedures such as drying, cold pressing, cutting and the like to prepare the anode plate. And the prepared positive electrode plate, the negative electrode plate prepared by the method, the diaphragm and the electrolyte are together used for preparing the secondary battery according to the method.
Test method
(1) Pole piece scanning electron microscope image
SEM imaging was performed on the positive pole piece using a Zeiss Sigma500 type field emission scanning electron microscope.
(2) Cycle capacity retention test
At 25 ℃, the cycle is carried out in a charge-discharge system of 0.21A/g (calculated by the mass of the anode material) and 2.5-3.65V. After cycling to 500 weeks, dividing the discharge capacity of the battery at the moment by the discharge capacity of the first cycle, namely the 500-cycle capacity retention rate of the battery.
(3) Pole piece resistance test
The positive electrode sheet was tested using a Hitachi diaphragm resistance meter RM 9003.
(4) Direct Current Resistance (DCR) test
And (3) discharging the battery to 50% SOC (state of charge) at a specified temperature, regulating the current to 4C, maintaining for 30s, and detecting the difference between the updated stable voltage and the original platform voltage, wherein the ratio of the value to the 3C current value is the direct current resistance of the battery. The DCR test result performed after the first full charge of the battery is the initial DCR of the battery.
Test results
As shown in fig. 2 and fig. 3, according to the method of the present invention, the positive electrode sheet prepared by using PVP as the dispersing agent still has a large amount of agglomeration in the image of the coating layer compared with the positive electrode sheet prepared without adding the dispersing agent, which indicates that the dispersing effect of PVP as the dispersing agent on the positive electrode material is not obvious.
As shown in fig. 1, according to the method of the present invention, the coating layer of the positive electrode sheet using the styrene-acrylate copolymer as the dispersing agent has significantly reduced agglomeration compared with that of fig. 2 and 3, which indicates that the styrene-acrylate copolymer as the dispersing agent has significantly improved dispersing effect on the positive electrode material and significantly dispersing effect on the conductive agent carbon black.
Table 1 below shows the test results of the cyclic capacity retention test, the pole piece resistance test, and the dc resistance test of examples 1 to 6 and comparative examples 1 to 3.
TABLE 1
As shown in table 1, the pole pieces of examples 1 to 6 have smaller pole piece resistivity than comparative examples 1 to 3, and when the amount of the dispersant added was gradually increased from 0.1 wt% to 2 wt% (based on the total weight of the positive electrode active material, the conductive agent, the binder and the dispersant in the positive electrode material), the pole piece resistivity was decreased and then increased, and when the amount of the dispersant added was 0.5%, the minimum pole piece resistivity was exhibited, which was significantly smaller than that of comparative examples 1 to 3.
Examples 1 to 6 also have smaller direct current resistance than comparative examples 1 to 3, and when the amount of the dispersant added was gradually increased from 0.1% by weight to 2% by weight (based on the total weight of the positive electrode active material, the conductive agent, the binder and the dispersant in the positive electrode material), the direct current resistance was increased first and then decreased and then increased, and when the amount of the dispersant added was 0.5%, the minimum direct current resistance was exhibited, which was significantly smaller than that of comparative examples 1 to 3.
Meanwhile, examples 1 to 6 have higher circulation capacity retention rates than comparative examples 1 to 3, and when the addition amount of the dispersant is gradually increased from 0.1 wt% to 2 wt% (based on the total weight of the positive electrode active material, the conductive agent, the binder and the dispersant in the positive electrode material), the circulation capacity retention rate is increased and then decreased, and when the addition amount of the dispersant is 0.5%, the maximum circulation capacity retention rate is exhibited, which is significantly higher than that of comparative examples 1 to 3.
In particular, when the content of the dispersant is 0.2 to 0.5% (based on the total weight of the positive electrode active material, the conductive agent, the binder and the dispersant in the positive electrode material), as the addition amount of the dispersant increases, the sheet resistivity and the direct current resistance decrease, the cyclic capacity retention increases, and relatively better sheet resistivity, direct current resistance and/or cyclic capacity retention can be obtained. When the dispersant content is 0.5% (based on the total weight of the positive electrode active material, the conductive agent, the binder and the dispersant in the positive electrode material), the optimal sheet resistivity, direct current resistance and cyclic capacity retention are exhibited.
By combining the results, the conductive agent carbon black in the positive electrode material can be effectively dispersed by using the dispersing agent, so that the coating of the positive electrode plate prepared by the method has uniformly distributed positive electrode material, and the positive electrode plate with lower resistivity is obtained. The secondary battery comprising or prepared from the positive electrode sheet of the invention has lower direct current resistance and higher cycle capacity retention rate.
The foregoing description of the embodiments of the present invention should not be construed as limiting the scope of the invention, but rather should be construed in view of the appended claims, as well as any equivalents thereof, or direct or indirect application in other relevant technical fields.
Claims (10)
1. A dispersant for a positive electrode material, characterized in that,
the dispersant comprises a copolymer formed by copolymerizing the following (a) and (b),
(a) Substituted or unsubstituted phenyl-substituted olefin monomers,
(b) An ester group-substituted olefin monomer,
wherein, the liquid crystal display device comprises a liquid crystal display device,
(a) And (b) each independently is an olefin monomer comprising 2 to 6 carbon atoms.
2. The dispersant according to claim 1, wherein,
(a) The olefin monomer in (a) is styrene monomer; and/or
(b) The olefin monomer in (2) is an acrylic ester monomer.
3. The dispersant according to claim 1, wherein,
the molecular weight of the copolymer is 10000 or less.
4. The dispersant according to claim 1, wherein,
(a) The molar ratio of olefin monomer in (a) to olefin monomer in (b) is 1:3-3:1.
5. the dispersant as claimed in claim 4, wherein,
(a) The molar ratio of olefin monomer in (a) to olefin monomer in (b) is 1:1-1.1:1.
6. The dispersant according to claim 1, wherein,
the copolymer comprises the following structural units:
wherein R is 1 Selected from C 1-6 An alkyl group;
each R 2 Independently selected from hydrogen, C 1-6 Alkyl, halogen;
p is selected from integers from 0 to 5;
the ratio of n to m is 1:3-3:1,
7. The dispersant according to claim 1, wherein,
the copolymer comprises the following structural units:
wherein R is 1 Selected from C 1-6 An alkyl group;
each R 2 Independently selected from hydrogen, C 1-6 Alkyl, halogen;
p is selected from integers from 0 to 5.
8. A positive electrode sheet, characterized in that the positive electrode sheet comprises:
a positive electrode current collector and a positive electrode material coated on the surface of the current collector;
the positive electrode material contains a positive electrode active material, a conductive agent, a binder, a solvent, and the dispersant of any one of claims 1 to 7.
9. The positive electrode sheet according to claim 8, wherein,
the content of the dispersing agent is 0.1 to 2 wt% based on the total weight of the positive electrode active material, the conductive agent, the binder and the dispersing agent in the positive electrode material.
10. A lithium ion secondary battery, characterized in that the lithium ion secondary battery comprises:
The positive electrode sheet of any one of claims 8 to 9;
a negative electrode plate;
an electrolyte; and
a diaphragm.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117209653A (en) * | 2023-11-09 | 2023-12-12 | 江苏一特新材料有限责任公司 | Three-chain-segment polymer dispersing agent, preparation method thereof and lithium manganese iron phosphate positive electrode slurry |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117209653A (en) * | 2023-11-09 | 2023-12-12 | 江苏一特新材料有限责任公司 | Three-chain-segment polymer dispersing agent, preparation method thereof and lithium manganese iron phosphate positive electrode slurry |
| CN117209653B (en) * | 2023-11-09 | 2024-01-02 | 江苏一特新材料有限责任公司 | Three-chain-segment polymer dispersing agent, preparation method thereof and lithium manganese iron phosphate positive electrode slurry |
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