WO2023226765A1 - 正极活性材料及包括该正极活性材料的正极片和电池 - Google Patents

正极活性材料及包括该正极活性材料的正极片和电池 Download PDF

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WO2023226765A1
WO2023226765A1 PCT/CN2023/093273 CN2023093273W WO2023226765A1 WO 2023226765 A1 WO2023226765 A1 WO 2023226765A1 CN 2023093273 W CN2023093273 W CN 2023093273W WO 2023226765 A1 WO2023226765 A1 WO 2023226765A1
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active material
group
acid
positive electrode
battery
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PCT/CN2023/093273
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English (en)
French (fr)
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莫耀华
唐伟超
赵伟
李素丽
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珠海冠宇电池股份有限公司
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Publication of WO2023226765A1 publication Critical patent/WO2023226765A1/zh

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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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/60—Selection of substances as active materials, active masses, active liquids of organic compounds
    • 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
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • 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

Definitions

  • the present disclosure relates to a positive active material, a positive electrode sheet and a battery including the positive active material, and belongs to the field of battery technology, specifically to the field of quasi-solid-state batteries.
  • NCM ternary material Layered nickel-cobalt-manganese cathode material
  • NCM ternary material is a promising material with low cost, large discharge capacity, and good cycle performance.
  • the demand for the specific energy density of cathode materials has also increased accordingly, thus promoting the continuous improvement of nickel content in NCM ternary materials.
  • the increase in nickel content in NCM ternary materials has brought about a series of problems. The most direct problem is that the increase in nickel content leads to an increase in the water absorption of NCM ternary materials, which ultimately leads to the loss of high-nickel NCM ternary materials during storage.
  • M-OH Reacts with water and carbon dioxide in the air to produce groups such as M-OH, M-O-OH (M is Ni, Co or Mn), as well as impurities such as lithium hydroxide and lithium carbonate. These groups turn the material into alkaline.
  • the slurry will cause flocculation, jelly, etc. and be scrapped.
  • this material when this material is used as a quasi-solid battery cathode material, it will react with the electrolyte to generate HF, carbon dioxide and other gases, which will reduce the interface contact between the cathode material and the quasi-solid electrolyte, leading to battery failure.
  • the current methods to solve the above problems are mainly to coat the surface of ternary materials with metal oxides such as Al 2 O 3 and fast ion conductors such as lithium phosphate to inhibit HF corrosion.
  • metal oxides such as Al 2 O 3
  • fast ion conductors such as lithium phosphate
  • these methods cannot reduce the M-OH, Groups such as MO-OH will also produce gas in quasi-solid-state batteries.
  • the present disclosure proposes a cathode active material, a cathode sheet and a battery including the cathode active material.
  • the positive active material is to introduce organic acid monomers (such as unsaturated carboxylic acid monomers, unsaturated phosphonic acid monomers or unsaturated sulfonic acid monomers) into the ternary material, and combine the organic acid monomer with the ternary material.
  • organic acid monomers such as unsaturated carboxylic acid monomers, unsaturated phosphonic acid monomers or unsaturated sulfonic acid monomers
  • the M-OH groups and/or MO-OH groups on the surface react to generate ester groups, which tightly combine the organic acid monomer with the ternary material.
  • the organic acid monomer can also absorb the lithium carbonate that has been produced on the surface of the ternary material. and lithium hydroxide are converted into lithium organic acid to reduce the amount of gas produced when the battery is used.
  • the positive active material includes a ternary material and a surface graft of the ternary material, and/or a graft-modified ternary material.
  • the graft includes an organic acid monomer.
  • the organic acid monomer includes a terminal alkenyl group and an acid functional group.
  • the organic acid monomer includes at least one compound represented by Formula 1:
  • R 1 is absent or an alkylene group of C 1 to 10 , an arylene group of C 6 to 14 , or -CONH-alkylene group of C 1 to 10 ;
  • R 2 is H or an alkylene group of C 1 to 6 Alkyl group;
  • R 3 is carboxyl group, phosphonic acid group or sulfonic acid group.
  • the organic acid monomer includes one or more of the following compounds: acrylic acid, vinyl acetic acid, vinyl propionic acid, vinyl butyric acid, hept-6-enoic acid, vinyl pentanoic acid Acid, methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, p-styrenesulfonic acid, p-styreneformic acid, vinylphosphonic acid.
  • the mass of the graft accounts for 0.2wt% to 2wt% of the total mass of the cathode active material.
  • the present disclosure also provides a positive electrode sheet, which includes the above-mentioned positive electrode active material.
  • the present disclosure also provides a battery, which includes the positive active material or the positive sheet.
  • the battery further includes an electrolyte, the electrolyte contains a cross-linked polymer, and the cross-linked polymer contains carbon-carbon double bonds and/or epoxy groups.
  • the cross-linked polymer is a cross-linked polymer of the cathode active material and a polymerized monomer containing a carbon-carbon double bond and/or an epoxy group.
  • the content of the polymerized monomer containing carbon-carbon double bonds and/or epoxy groups is 0.5 wt% to 8 wt% of the total mass of the ternary material in the cathode active material.
  • the cross-linked polymer is formed by connecting the terminal alkenyl group in the positive electrode active material and the carbon-carbon double bond and/or ring in the polymerized monomer containing carbon-carbon double bond and/or epoxy group. It is obtained by cross-linking polymerization reaction of oxygen groups.
  • the polymerized monomer containing a carbon-carbon double bond and/or an epoxy group has at least one of a compound represented by Formula 3, a compound represented by Formula 4, and a compound represented by Formula 5:
  • R 6 R 7 C CR 8 (R-epoxy group)
  • Formula 4 Epoxy-R-epoxy Formula 5
  • R is an organic group
  • R 6 to R 14 are the same or different, and are independently selected from H or a C 1-6 alkyl group (preferably H or a C 1-3 alkyl group, such as H or CH 3 );
  • Ring The oxygen group is selected from the group consisting of epoxypropyl, epoxybutyl, epoxypentyl, dioxane, dioxacyclyl and tetrahydrofuryl.
  • Adding organic acid monomers during the preparation process of the pole piece can effectively reduce the content of alkaline substances on the surface of the ternary material, reduce the gas production of the ternary material in the battery, and improve the cycle stability of the pole piece in the battery. .
  • the organic acid monomer is tightly combined on the surface of the ternary material, and participates in the curing reaction when solidified in situ to form a quasi-solid-state battery, so that the ternary material and the solid electrolyte have A closer contact interface improves the stability of the battery during cycling.
  • the cathode active material includes a ternary material and a ternary material surface graft, and/or a graft-modified ternary material.
  • the graft includes Organic acid monomer.
  • the cathode active material includes a ternary material and a ternary material surface graft.
  • the cathode active material includes a graft-modified ternary material.
  • the organic acid monomer includes a terminal alkenyl group and an acid functional group.
  • the organic acid monomer includes at least one compound represented by Formula 1:
  • R 1 is absent or an alkylene group of C 1 to 10 , an arylene group of C 6 to 14 , or -CONH-alkylene group of C 1 to 10 ;
  • R 2 is H or an alkylene group of C 1 to 6 Alkyl group;
  • R 3 is carboxyl group, phosphonic acid group or sulfonic acid group.
  • the R 1 is absent or an alkylene group with 1 to 6 carbon atoms, an arylene group with 6 to 12 carbon atoms, or -CONH-alkylene group with 1 to 6 carbon atoms.
  • the R 1 is absent or an alkylene group with 1 to 3 carbon atoms, an arylene group with 6 to 8 carbon atoms, or -CONH-alkylene group with 1 to 3 carbon atoms.
  • R 2 is H or a C 1-3 alkyl group.
  • R 2 is H or methyl.
  • the organic acid monomer includes one or more of the following compounds: acrylic acid, vinyl acetic acid, vinyl propionic acid, vinyl butyric acid, hept-6-enoic acid, vinyl pentanoic acid Acid, methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, p-styrenesulfonic acid, p-styreneformic acid, vinylphosphonic acid.
  • the chemical formula of the ternary material is Li a Ni x Co y M' 1-xy Ak O 2 , where, 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, 0 ⁇ x+y ⁇ 1, 0.9 ⁇ a ⁇ 1.1, 0 ⁇ k ⁇ 0.1, M' is Mn or Al, A is a dopant selected from the following elements: Co, Cu, Zn, Fe, Al, Mg, Ti, Zr, Y , B, La, Mo, Nb, P, Mn or combinations thereof.
  • the chemical formula of the ternary material is LiNix Co y M' 1-xy O 2 , where, 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, 0 ⁇ x+y ⁇ 1, M ' is Mn or Al.
  • the ternary material is a nickel-cobalt-aluminum ternary material.
  • the nickel-cobalt-aluminum ternary material has a layered structure and is a quasi-spherical secondary particle formed by stacking flaky primary particles.
  • the chemical formula of the nickel-cobalt-aluminum ternary material is Li a Ni x Co y Al 1-xy A k O 2 , 0 ⁇ x ⁇ 1.1, 0 ⁇ y ⁇ 1, 0 ⁇ x+y ⁇ 1, 0.9 ⁇ a ⁇ 1, 0 ⁇ k ⁇ 0.1,
  • A is a dopant selected from the following elements: Co, Cu, Zn, Fe, Al, Mg, Ti, Zr, Y, B, La, Mo, Nb, P, Mn or combinations thereof.
  • the chemical formula of the nickel-cobalt-aluminum ternary material is LiNix Co y Al 1-xy O 2 , 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, 0 ⁇ x+y ⁇ 1.
  • the ternary material is a nickel-cobalt-manganese ternary material.
  • the nickel-cobalt-manganese ternary material has a layered structure and includes spherical-like secondary particles stacked by primary particles.
  • the chemical formula of the nickel-cobalt-manganese ternary material is Li a Ni x Co y Mn 1-xy A k O 2 , 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, 0 ⁇ x+y ⁇ 1, 0.9 ⁇ a ⁇ 1.1, 0 ⁇ k ⁇ 0.1,
  • A is a dopant selected from the following elements: Co, Cu, Zn, Fe, Al, Mg, Ti, Zr, Y, B, La, Mo, Nb, P, Mn or other combination.
  • the chemical formula of the nickel-cobalt-manganese ternary material is LiNix Co y Mn 1-xy O 2 , 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, 0 ⁇ x+y ⁇ 1.
  • primary particles and “secondary particles” have conventional meanings in the art.
  • the term “primary particles” refers to a single positive active particle; the term “secondary particles” refers to particles formed by the accumulation of several flaky primary particles.
  • the secondary particles are formed after the agglomeration of two flaky primary particles. particles, particles formed after the agglomeration of 5 flaky primary particles, particles formed after the agglomeration of 10 flaky primary particles, particles formed after the agglomeration of 50 flaky primary particles, or particles formed after the agglomeration of 100 flaky primary particles. .
  • the surface of the ternary material contains groups such as M-OH and M-O-OH, M is at least one of Ni, Co and M’, and M’ is Mn or Al.
  • the mass of the graft accounts for 0.2wt% ⁇ 2wt% of the total mass of the cathode active material, preferably 0.4wt% ⁇ 1.5wt%, and more preferably 0.5wt% ⁇ 1wt%, for example, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, 1.1wt%, 1.2wt%, 1.3wt %, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt% or 2wt%.
  • the cathode active material has one of the following structures:
  • M is Ni, Co or Mn
  • R 1 and R 2 are as defined above
  • *-P( O)(OH)O-
  • n' is an integer greater than or equal to 1, which represents the number of grafts.
  • n' is an integer between 1 and 1000.
  • n' is an integer between 1 and 500.
  • the content of alkaline substances (lithium carbonate and/or lithium hydroxide) on the surface of the ternary material can be effectively reduced, and the production of the ternary material in the battery can be reduced.
  • the gas volume improves the cycle stability of the electrode piece in the battery.
  • the organic acid monomer layer formed on the surface of the ternary material prepares for subsequent in-situ curing.
  • the present disclosure also provides a method for preparing the above-mentioned positive electrode active material, which method includes the following steps:
  • step 2) Add the ternary material to the solution in step 1) and react to prepare the positive active material.
  • the organic solvent is selected from at least one of NMP (N-methylpyrrolidone), DMAC (dimethylacetamide) and DMF (N,N-dimethylformamide).
  • the reaction temperature is 40-60°C, such as 45°C, and the reaction time is 4-12h, such as 6h.
  • the present disclosure also provides a positive electrode sheet, which includes the above-mentioned positive electrode active material.
  • the cathode sheet includes a current collector and a cathode active layer located on at least one side surface of the current collector, and the cathode active layer includes the above-mentioned cathode active material.
  • the cathode active layer further includes a conductive agent.
  • the conductive agent is selected from one or more of conductive carbon black, acetylene black, Ketjen black, carbon fiber, graphene, single-walled carbon nanotubes and multi-walled carbon nanotubes.
  • the cathode active layer further includes a binder.
  • the binder is selected from carboxymethylcellulose, sodium carboxymethylcellulose, lithium carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, polyethylene, polyethylene Alcohol, polyvinyl chloride, polyvinyl fluoride, polyvinylpyrrolidone, polytetrafluoroethylene, polypropylene, styrene-butadiene rubber, epoxy resin, butadiene rubber adhesive and acrylonitrile One or more types of adhesives.
  • the current collector is selected from one or more of aluminum foil, carbon-coated aluminum foil and perforated aluminum foil.
  • the mass percentage of each component in the cathode active layer is: 91wt% to 97.5wt% of the above cathode active material, 0.5wt% to 4wt% conductive agent, 2wt% to 5wt% of adhesive.
  • the present disclosure also provides a method for preparing the above-mentioned positive electrode sheet, which includes the following steps:
  • step (b) Add the ternary material to the solution in step (a) and react to obtain a dispersion;
  • step (c) Add a conductive agent and a binder to the dispersion in step (b), mix thoroughly, apply on the surface of the current collector, and dry to obtain the positive electrode sheet.
  • the present disclosure also provides a battery, which includes the positive active material or the positive sheet.
  • the battery further includes an electrolyte, the electrolyte contains a cross-linked polymer, and the cross-linked polymer contains carbon-carbon double bonds and/or epoxy groups.
  • the cross-linked polymer is a cross-linked polymer of the above-mentioned cathode active material and a polymerized monomer containing a carbon-carbon double bond and/or an epoxy group.
  • the polymerized monomer containing carbon-carbon double bonds and/or epoxy groups may be: a polymerized monomer containing only carbon-carbon double bonds, a polymerized monomer containing only epoxy groups, or both. Polymerized monomers containing carbon-carbon double bonds and epoxy groups.
  • the content of the polymerized monomer containing carbon-carbon double bonds and/or epoxy groups is 0.5wt% to 8wt% of the total mass of the ternary material in the cathode active material, preferably 1wt% to 5wt %, more preferably 1.5wt% to 4wt%, such as 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, 5.5 wt%, 6wt%, 6.5wt%, 7wt%, 7.5wt% or 8wt%.
  • the cross-linked polymer is formed by combining the terminal alkenyl group in the above-mentioned cathode active material and the carbon-carbon double bond and/or ring in the polymerized monomer containing carbon-carbon double bond and/or epoxy group. Oxygen groups cross-link the polymer Obtained from the synthesis reaction.
  • the cross-linked polymer is filled in the voids of the positive electrode sheet, the voids of the negative electrode sheet, and the voids of the separator.
  • the cross-linked polymer has a three-dimensional network structure, and the liquid electrolyte (liquid electrolyte injected during the battery preparation process) is filled in the gaps of the three-dimensional network structure to form a gel electrolyte or a solid electrolyte .
  • the battery is a quasi-solid-state battery.
  • the cross-linked polymer has a structural unit represented by Formula 2:
  • M is an integer between 1 and 1000; n is an integer between 1 and 500.
  • m is an integer between 300 and 800.
  • n is an integer between 100 and 300.
  • the R is a group after polymerization of a polymerized monomer containing a carbon-carbon double bond and/or an epoxy group.
  • the epoxy group in the polymerized monomer containing a carbon-carbon double bond and/or an epoxy group is, for example, glycidyl, epoxybutyl, epoxypentyl, dioxane base, dioxacyclyl, tetrahydrofuranyl.
  • R is an organic group
  • R 6 to R 14 are the same or different, and are independently selected from H or a C 1-6 alkyl group (preferably H or a C 1-3 alkyl group, such as H or CH 3 ).
  • the polymerized monomer containing carbon-carbon double bonds and/or epoxy groups is, for example, at least one selected from the following compounds: pentaerythritol tetraacrylate, trimethylolpropane trimethacrylate , Ethoxylated trimethylolpropane triacrylate, neopentyl glycol diacrylate, 1,5-pentanediol diacrylate, 3-(acryloyloxy)-2-hydroxypropyl methacrylate Ester, glycidyl acrylate, 3-(allyloxy)oxetane, oxetane methacrylate, glycidyl methacrylate, tetrahydrofurfuryl acrylate, 1,6-di (Acryloyloxy)-2,2,3,3,4,4,5,5-octafluorohexane.
  • pentaerythritol tetraacrylate trimethylolpropane trimethacrylate
  • the structural formula of the above-mentioned polymerized monomer is as follows:
  • the present disclosure also provides a method for preparing the above-mentioned battery, which includes the following steps:
  • step (b) Add the ternary material to the solution in step (a) and react to obtain a dispersion;
  • step (c) Add a conductive agent and a binder to the dispersion in step (b), mix thoroughly, apply it on the surface of the current collector, and dry to obtain the positive electrode sheet;
  • step (d) Assemble the positive electrode sheet, negative electrode sheet and separator of step (c) into a battery, then inject an electrolyte containing polymerized monomers and initiators containing carbon-carbon double bonds and/or epoxy groups, and solidify to prepare the above-mentioned Battery.
  • the step (c) specifically includes the following steps: adding a conductive agent and a binder to the dispersion of step (b), mixing thoroughly, coating, and then baking at 100°C to remove the solvent. , and then vacuum drying at 100°C to further remove the solvent to prepare a positive electrode sheet.
  • the content of the organic acid monomer is 0.2wt% to 2wt% of the total mass of the ternary material, preferably 0.4wt% to 1.5wt%, and more preferably 0.5wt% to 1wt%.
  • the content of the polymerized monomer containing carbon-carbon double bonds and/or epoxy groups is 0.2wt% to 10wt% of the total mass of the electrolyte, preferably 0.5wt% to 7wt%, and more preferably It is 2wt% ⁇ 5wt%.
  • the content of the polymerized monomer containing carbon-carbon double bonds and/or epoxy groups is 0.5wt% to 8wt% of the total mass of the ternary material, preferably 1wt% to 5wt%, and more preferably It is 1.5wt% ⁇ 4wt%.
  • the initiator is a free radical initiator, including but not limited to azobisisobutyronitrile, azobisisoheptanitrile, dimethyl azobisisobutyrate, benzoyl peroxide , diisopropyl peroxydicarbonate and tert-butyl peroxybenzoate, etc., the added amount is polymerized monomers containing carbon-carbon double bonds and/or epoxy groups. 0.5wt% ⁇ 3wt% of the total mass.
  • NCM811 positive electrode slurry After stirring and mixing, add 2 parts by mass of conductive agent carbon black and 1 part by mass of binder PVDF (polyvinylidene fluoride) and mix thoroughly to prepare NCM811 positive electrode slurry, and coat it on the surface of an aluminum foil with a thickness of 10 ⁇ m, and then After drying the solvent at 80°C, vacuum drying at 100°C, and rolling under a pressure of 40 tons, the compacted density is 3.4-4.2g/cm 3 to obtain a positive electrode sheet.
  • binder PVDF polyvinylidene fluoride
  • the above-mentioned positive electrode sheet, negative electrode sheet, polyethylene (PE) porous separator (wet separator ND12 produced by Shanghai Enjie New Material Technology Co., Ltd., thickness 12 ⁇ m) were assembled by winding, and then the electrolyte (Shenzhen Xinzhoubang Technology Co., Ltd.'s LBC445B33 model electrolyte), the electrolyte includes:
  • a battery was prepared by using 2% trimethylolpropane trimethacrylate (polymerized monomer) and 1% AIBN initiator (azobisisobutyronitrile) by weight of the polymerized monomer.
  • the prepared battery was aged for 48 hours and then hot-pressed and cured at 80°C for 3 hours to obtain a quasi-solid-state battery.
  • Example 1 Preparation of the positive electrode sheet: The difference from Example 1 is that 1.5 parts by mass of 2-acrylamido-2-methylpropanesulfonic acid was dissolved in 50 parts by mass of NMP, and then 95.5 parts by mass of NCM811 was added. Other processes are the same as Example 1.
  • Battery preparation The same as the example, except that the injected electrolyte contains 5 wt% of 1,5-pentanediol diacrylate and 1% of the AIBN initiator by mass of polymerized monomers.
  • Example 1 Preparation of the positive electrode sheet: The difference from Example 1 is that 0.5 parts by mass of 2-acrylamido-2-methylpropanesulfonic acid was dissolved in 50 parts by mass of NMP, and then 96.5 parts by mass of NCM811 was added. Other processes are the same as Example 1.
  • Example 2 The same as Example 1, except that the injected electrolyte contained 1 wt% of 3-(allyloxy)oxetane and 1% of AIBN initiator by mass of polymerized monomers.
  • Example 1 Preparation of the positive electrode sheet: The difference from Example 1 is that 0.8 parts by mass of 2-acrylamido-2-methylpropanesulfonic acid was dissolved in 50 parts by mass of NMP, and then 96.2 parts by mass of NCM811 was added. Other processes are the same as Example 1.
  • Battery preparation The same as the example, except that the injected electrolyte contains 0.5 wt% pentaerythritol tetraacrylate and 1% AIBN initiator by mass of polymerized monomers.
  • Negative electrode sheet preparation is the same as in Example 1.
  • the above-mentioned positive electrode sheet, negative electrode sheet, polyethylene (PE) porous separator (wet separator ND12 produced by Shanghai Enjie New Material Technology Co., Ltd., thickness 12 ⁇ m) were assembled by winding, and then the electrolyte (Shenzhen Xinzhoubang Technology Co., Ltd.'s LBC445B33 model electrolyte), which includes: 1,5-pentanediol diacrylate (polymerized monomer) accounting for 5% of the mass of the electrolyte and AIBN initiator accounting for 1% of the mass of the polymerized monomer. agent to prepare a battery. The prepared battery was aged for 48 hours and then hot-pressed and cured at 80°C for 3 hours to obtain a quasi-solid-state battery.
  • PE polyethylene
  • Preparation of positive electrode sheet The difference from Example 5 is that 1.5 parts by mass of vinylphosphonic acid was dissolved in 50 parts by mass of NMP, and then 95.5 parts by mass of NCM811 was added. Other processes are the same as in Example 5.
  • Preparation of positive electrode sheet The difference from Example 5 is that 0.5 parts by mass of vinylphosphonic acid was dissolved in 50 parts by mass of NMP, and then 96.5 parts by mass of NCM811 was added. Other processes are the same as in Example 5.
  • Preparation of positive electrode sheet The difference from Example 5 is that 0.8 parts by mass of vinylphosphonic acid was dissolved in 50 parts by mass of NMP, and then 96.2 parts by mass of NCM811 was added. Other processes are the same as in Example 5.
  • Preparation of positive electrode sheet The difference from Example 5 is that 1 part by mass of acrylic acid was dissolved in 50 parts by mass of NMP, and then 96 parts by mass of NCM811 was added. Other processes are the same as in Example 5.
  • Example 5 The difference from Example 5 is that the electrolyte added with 2% of the electrolyte mass of 1,5-pentanediol diacrylate and 1% of the monomer mass of the AIBN initiator was injected.
  • Preparation of positive electrode sheet The difference from Example 5 is that 1.5 parts by mass of acrylic acid was dissolved in 50 parts by mass of NMP, and then 95.5 parts by mass of NCM811 was added. Other processes are the same as in Example 5.
  • Example 5 The difference from Example 5 is that the electrolyte containing 2% by mass of the electrolyte of 1,5-pentanediol diacrylate and 1% by mass of the polymerized monomer AIBN initiator was added.
  • Preparation of the positive electrode sheet The difference from Example 5 is that 0.5 parts by mass of acrylic acid was dissolved in 50 parts by mass of NMP, and then 96.5 parts by mass of NCM811 was added. Other processes are the same as in Example 5.
  • Example 5 The difference from Example 5 is that the electrolyte containing 2% of the mass of the electrolyte solution of 1,5-pentanediol diacrylate and 1% of the mass of the polymerized monomer AIBN initiator is added.
  • Preparation of positive electrode sheet The difference from Example 5 is that 0.8 parts by mass of acrylic acid was dissolved in 50 parts by mass of NMP, and then 96.2 parts by mass of NCM811 was added. Other processes are the same as in Example 5.
  • Example 5 The difference from Example 5 is that the electrolyte containing 2% by mass of the electrolyte of 1,5-pentanediol diacrylate and 1% by mass of the polymerized monomer AIBN initiator was added.
  • Preparation of positive electrode sheet The difference from Example 1 is that the positive electrode material is 97 parts by mass of untreated NCM811 (Xiamen Tungsten Industry).
  • Preparation of positive electrode sheet The difference from Example 1 is that the positive electrode material is 97 parts by mass of NCM811 (Xiamen Tungsten Industry) whose surface is coated with 1% mass fraction of alumina.
  • NCM811 Xiamen Tungsten Industry
  • Preparation of positive electrode sheet The difference from Example 1 is that 1 part by mass of polyacrylic acid (PAA) is added instead of 2-acrylamido-2-methylpropanesulfonic acid monomer.
  • PAA polyacrylic acid
  • Preparation of positive electrode sheet The difference from Example 1 is that 1 mass part of PVDF-HFP (polyvinylidene fluoride-hexafluoropropylene 2500 Arkema) is added instead of 2-acrylamido-2-methylpropanesulfonic acid mono body.
  • PVDF-HFP polyvinylidene fluoride-hexafluoropropylene 2500 Arkema
  • Battery inflation rate The proportion of 100 batteries that experience inflation after 500 cycles.
  • Cycle life test method Refer to the GB/T18287-2013 standard to test the cycle performance of the battery and take the capacity retention rate after 500 cycles.
  • the cycle test conditions are: 25°C, 0.5C/0.5C charge and discharge (the upper limit voltage is set to 4.3V , lower limit voltage 2.75V).
  • the gas expansion rate of the cathode active material obtained after the reaction of the organic acid monomer and the ternary material is significantly improved after in-situ assembly into the battery, and the cycle capacity retention rate is also greatly improved.

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  • Chemical Kinetics & Catalysis (AREA)
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Abstract

本公开涉及一种正极活性材料及包括该正极活性材料的正极片和电池，属于电池技术领域，具体属于准固态电池领域。在极片制备过程中加入有机酸单体可以有效的降低三元材料表面的碱性物质的含量，减少三元材料在电池中的产气量，提高极片在电池中的循环稳定性。通过有机酸单体与三元材料反应，使有机酸单体紧密的结合在三元材料表面，在原位固化成准固态电池时参与固化反应从而使三元材料与固态电解质具有更紧密的接触界面，提高电池在循环中的稳定性。

Description

正极活性材料及包括该正极活性材料的正极片和电池 技术领域
本公开涉及一种正极活性材料及包括该正极活性材料的正极片和电池，属于电池技术领域，具体属于准固态电池领域。
背景技术
层状镍钴锰正极材料(NCM三元材料)是一种极具发展前景的材料，具有成本低、放电容量大、循环性能好等优点。随着人们对电池能量密度需求的不断增加，对正极材料的比能量密度的需求也相应增加，从而促进NCM三元材料中镍含量的不断提升。但是NCM三元材料中镍含量的增加带来了一系列问题，其中最直接的问题是镍含量的增加导致NCM三元材料的吸水性增加，最终导致高镍NCM三元材料在存储过程中会与空气中的水和二氧化碳反应，产生M-OH、M-O-OH(M为Ni、Co或Mn)等基团，以及氢氧化锂和碳酸锂等杂质，这些基团使材料转变成碱性，在正极浆料配制时使浆料产生絮凝、果冻等状况而报废。另外，这种材料在作为准固态电池正极材料使用时会与电解液反应生成HF，二氧化碳等气体，降低正极材料与准固态电解质的界面接触从而导致电池失效。
目前解决上述问题的方法主要是在三元材料表面包覆Al2O3等金属氧化物以及磷酸锂等快离子导体以抑制HF腐蚀，但是这些方法并不能降低材料本身会产生的M-OH、M-O-OH等基团，在准固态电池中同样会有气体的产生。
发明内容
针对上述问题，本公开提出一种正极活性材料及包括该正极活性材料的正极片和电池。所述正极活性材料是在三元材料中引入有机酸单体(如不饱和羧酸单体、不饱和膦酸单体或不饱和磺酸单体)，并通过有机酸单体与三元材料表面的M-OH基团和/或M-O-OH基团反应生成酯基，使有机酸单体与三元材料结合紧密，所述有机酸单体还可以将三元材料表面已经产生的碳酸锂和氢氧化锂转换为有机酸锂，减少电池使用时的产气量。
本公开具体提供如下技术方案：
一种正极活性材料，所述正极活性材料包括三元材料及三元材料表面接枝物，和/或接枝改性的三元材料，所述接枝物包括有机酸单体。
本公开的一实例中，所述有机酸单体包括端烯基和酸官能团。
本公开的一实例中，所述酸官能团选自羧基-C(＝O)OH、磷酸基-P(＝O)(OH)2或磺酸基-S(＝O)(＝O)OH。
本公开的一实例中，所述有机酸单体包括至少一种式1所示的化合物：
式1中，R1为不存在或C1～10的亚烷基、C6～14的亚芳基、-CONH-C1～10的亚烷基；R2为H或者C1～6的烷基；R3为羧基、膦酸基或磺酸基。
根据本公开的实施方式，所述有机酸单体包括下列化合物中的一种或多种：丙烯酸、乙烯基乙酸、乙烯基丙酸、乙烯基丁酸、庚-6-烯酸、乙烯基戊酸、甲基丙烯酸、2-丙烯酰胺基-2-甲基丙磺酸、对苯乙烯磺酸、对苯乙烯甲酸、乙烯膦酸。
本公开的一实例中，所述正极活性材料中，接枝物的质量占正极活性材料总质量的0.2wt％～2wt％。
本公开还提供一种正极片，所述正极片包括上述的正极活性材料。
本公开还提供一种电池，所述电池包括所述的正极活性材料，或所述的正极片。
本公开的一实例中，所述电池还包括电解质，所述电解质中含有交联聚合物，所述交联聚合物中含有碳碳双键和/或环氧基。
本公开的一实例中，所述交联聚合物是所述正极活性材料与含有碳碳双键和/或环氧基的聚合单体的交联聚合物。
本公开的一实例中，所述含有碳碳双键和/或环氧基的聚合单体的含量为正极活性材料中三元材料总质量的0.5wt％～8wt％。
本公开的一实例中，所述交联聚合物是通过上述正极活性材料中的端烯基与含有碳碳双键和/或环氧基的聚合单体中的碳碳双键和/或环氧基进行交联聚合反应得到的。
本公开的一实例中，所述含有碳碳双键和/或环氧基的聚合单体具有式3所示化合物、式4所示化合物、式5所示化合物中的至少一种：
R6R7C＝CR8(R-环氧基)   式3
R9R10C＝CR11(RCR12＝CR13R14)   式4
环氧基-R-环氧基   式5
R为有机基团；R6～R14相同或不同，彼此独立地选自H或者C1～6的烷基(优选为H或者C1～3的烷基，如H或者CH3)；环氧基选自环氧丙基、环氧丁基、环氧戊基、二氧六环基、二氧五环基、四氢呋喃基。
本公开的有益效果：
(1)在极片制备过程中加入有机酸单体可以有效的降低三元材料表面的碱性物质的含量，减少三元材料在电池中的产气量，提高极片在电池中的循环稳定性。
(2)通过有机酸单体与三元材料反应，使有机酸单体紧密的结合在三元材料表面，在原位固化成准固态电池时参与固化反应，从而使三元材料与固态电解质具有更紧密的接触界面，提高电池在循环中的稳定性。
具体实施方式
如前所述，本公开提供一种正极活性材料，所述正极活性材料包括三元材料及三元材料表面接枝物，和/或接枝改性的三元材料，所述接枝物包括有机酸单体。
根据本公开的实施方式，所述正极活性材料包括三元材料和三元材料表面接枝物。
根据本公开的实施方式，所述正极活性材料包括接枝改性的三元材料。
根据本公开的实施方式，所述有机酸单体通过其酸官能团(如羧基-C(＝O)OH、磷酸基-P(＝O)(OH)2或磺酸基-S(＝O)(＝O)OH等)与三元材料表面的-OH或-O-OH的反应接枝到三元材料上。
根据本公开的实施方式，所述有机酸单体包括端烯基和酸官能团。
根据本公开的实施方式，所述有机酸单体包括至少一种式1所示的化合物：
式1中，R1为不存在或C1～10的亚烷基、C6～14的亚芳基、-CONH-C1～10的亚烷基；R2为H或者C1～6的烷基；R3为羧基、膦酸基或磺酸基。
根据本公开的实施方式，所述R1为不存在或C1～6的亚烷基、C6～12的亚芳基、-CONH-C1～6的亚烷基。优选地，所述R1为不存在或C1～3的亚烷基、C6～8的亚芳基、-CONH-C1～3的亚烷基。
根据本公开的实施方式，R2为H或者C1～3的烷基。优选地，R2为H或者甲基。
根据本公开的实施方式，R3为-COOH(-C(＝O)OH)、-PO3H2(-P(＝O)(OH)2)或-SO3H(-S(＝O)(＝O)OH)。
根据本公开的实施方式，所述有机酸单体包括下列化合物中的一种或多种：丙烯酸、乙烯基乙酸、乙烯基丙酸、乙烯基丁酸、庚-6-烯酸、乙烯基戊酸、甲基丙烯酸、2-丙烯酰胺基-2-甲基丙磺酸、对苯乙烯磺酸、对苯乙烯甲酸、乙烯膦酸。
根据本公开的实施方式，所述三元材料的化学式为LiaNixCoyM’1-x-yAkO2，其中，0<x<1，0<y<1，0<x+y<1，0.9≤a≤1.1，0≤k≤0.1，M’为Mn或Al，A为选自以下元素的掺杂剂：Co、Cu、Zn、Fe、Al、Mg、Ti、Zr、Y、B、La、Mo、Nb、P、Mn或其组合。
根据本公开的实施方式，所述三元材料的化学式为LiNixCoyM’1-x-yO2，其中，0<x<1，0<y<1，0<x+y<1，M’为Mn或Al。
根据本公开的实施方式，所述三元材料为镍钴铝三元材料，所述镍钴铝三元材料具有层状结构，是由片状一次颗粒堆积而成的类球形二次颗粒。所述镍钴铝三元材料的化学式为LiaNixCoyAl1-x-yAkO2，0<x<1.1，0<y<1，0<x+y<1，0.9≤a≤1，0≤k≤0.1，A为选自以下元素的掺杂剂：Co、Cu、Zn、Fe、Al、Mg、Ti、Zr、Y、 B、La、Mo、Nb、P、Mn或其组合。
根据本公开的实施方式，所述镍钴铝三元材料的化学式为LiNixCoyAl1-x-yO2，0<x<1，0<y<1，0<x+y<1。
根据本公开的实施方式，所述三元材料为镍钴锰三元材料，所述镍钴锰三元材料具有层状结构，包括由一次颗粒堆积而成的类球形二次颗粒。所述镍钴锰三元材料的化学式为LiaNixCoyMn1-x-yAkO2，0<x<1，0<y<1，0<x+y<1，0.9≤a≤1.1，0≤k≤0.1，A为选自以下元素的掺杂剂：Co、Cu、Zn、Fe、Al、Mg、Ti、Zr、Y、B、La、Mo、Nb、P、Mn或其组合。
根据本公开的实施方式，所述镍钴锰三元材料的化学式为LiNixCoyMn1-x-yO2，0<x<1，0<y<1，0<x+y<1。
术语“一次颗粒”和“二次颗粒”具有本领域常规的含义。术语“一次颗粒”是指单个正极活性颗粒；术语“二次颗粒”是指若干个片状一次颗粒堆积而成形成的颗粒，例如：所述二次颗粒为2个片状一次颗粒团聚后形成的颗粒、5个片状一次颗粒团聚后形成的颗粒、10个片状一次颗粒团聚后形成的颗粒、50个片状一次颗粒团聚后形成的颗粒或片状100个一次颗粒团聚后形成的颗粒。
根据本公开的实施方式，所述三元材料表面含有M-OH、M-O-OH等基团，M为Ni、Co和M’中的至少一种，所述M’为Mn或Al。
根据本公开的实施方式，所述正极活性材料中，接枝物的质量占正极活性材料总质量的0.2wt％～2wt％，优选为0.4wt％～1.5wt％，更优选为0.5wt％～1wt％，例如为0.2wt％、0.3wt％、0.4wt％、0.5wt％、0.6wt％、0.7wt％、0.8wt％、0.9wt％、1wt％、1.1wt％、1.2wt％、1.3wt％、1.4wt％、1.5wt％、1.6wt％、1.7wt％、1.8wt％、1.9wt％或2wt％。
根据本公开的实施方式，所述正极活性材料具有下述所示的结构中的一种：
其中，M为Ni、Co或Mn，R1和R2的定义如上所述，X为*-C(＝O)O-、*-P(＝O)(OH)O-、*-S(＝O)(＝O)O，*端与R1相连；n’为大于等于1的整数，代表的是接枝数。
根据本公开的实施方式，所述n’为1～1000之间的整数。
根据本公开的实施方式，所述n’为1～500之间的整数。
本公开中，在三元材料表面接枝有机酸单体后能够有效的降低三元材料表面的碱性物质(碳酸锂和/或氢氧化锂)的含量，减少三元材料在电池中的产气量，提高极片在电池中的循环稳定性，同时在三元材料表面形成的有机酸单体层，为后续的原位固化做准备。
本公开还提供上述正极活性材料的制备方法，所述方法包括如下步骤：
1)包括有机酸单体的接枝物溶解于有机溶剂中，得到溶液；
2)在步骤1)的溶液中加入三元材料，反应，制备得到所述正极活性材料。
根据本公开的实施方式，所述有机溶剂选自NMP(N-甲基吡咯烷酮)、DMAC(二甲基乙酰胺)和DMF(N,N-二甲基甲酰胺)中的至少一种。
根据本公开的实施方式，所述反应的温度为40～60℃，例如45℃，所述反应的时间为4～12h，例如6h。
本公开还提供一种正极片，所述正极片包括上述的正极活性材料。
根据本公开的实施方式，所述正极片包括集流体和位于集流体至少一侧表面的正极活性层，所述正极活性层中包括上述的正极活性材料。
根据本公开的实施方式，所述正极活性层还包括导电剂。在一些实施例中，所述导电剂选自导电炭黑、乙炔黑、科琴黑、碳纤维、石墨烯、单壁碳纳米管和多壁碳纳米管中的一种或几种。
根据本公开的实施方式，所述正极活性层还包括粘结剂。在一些实施例中，所述粘结剂选自羧甲基纤维素、羧甲基纤维素钠、羧甲基纤维素锂、羟丙基纤维素、二乙酰基纤维素、聚乙烯、聚乙烯醇、聚氯乙烯、聚氟乙烯、聚乙烯吡咯烷酮、聚四氟乙烯、聚丙烯、丁苯橡胶、环氧树脂、丁二烯类橡胶粘结剂和丙烯腈 类粘结剂的一种或几种。
根据本公开的实施方式，所述集流体选自铝箔、涂炭铝箔和打孔铝箔中的一种或几种。
根据本公开的实施方式，所述正极活性层中各组分的质量百分含量为：91wt％～97.5wt％的上述正极活性材料、0.5wt％～4wt％的导电剂、2wt％～5wt％的粘结剂。
本公开还提供一种上述正极片的制备方法，其包括如下步骤：
(a)包括有机酸单体的接枝物溶解于有机溶剂中，得到溶液；
(b)在步骤(a)的溶液中加入三元材料，反应，得到分散液；
(c)在步骤(b)的分散液中加入导电剂、粘结剂，充分混合后涂布在集流体表面，干燥后得到所述正极片。
本公开还提供一种电池，所述电池包括所述的正极活性材料，或所述的正极片。
根据本公开的实施方式，所述电池还包括电解质，所述电解质中含有交联聚合物，所述交联聚合物中含有碳碳双键和/或环氧基。
根据本公开的实施方式，所述交联聚合物是上述正极活性材料与含有碳碳双键和/或环氧基的聚合单体的交联聚合物。
根据本公开的实施方式，所述含有碳碳双键和/或环氧基的聚合单体可以为：只含有碳碳双键的聚合单体、只含有环氧基的聚合单体、或同时含有碳碳双键和环氧基的聚合单体。
根据本公开的实施方案，所述含有碳碳双键和/或环氧基的聚合单体的含量为正极活性材料中三元材料总质量的0.5wt％～8wt％，优选为1wt％～5wt％，更优选为1.5wt％～4wt％，例如为0.5wt％、1wt％、1.5wt％、2wt％、2.5wt％、3wt％、3.5wt％、4wt％、4.5wt％、5wt％、5.5wt％、6wt％、6.5wt％、7wt％、7.5wt％或8wt％。
根据本公开的实施方式，所述交联聚合物是通过上述正极活性材料中的端烯基与含有碳碳双键和/或环氧基的聚合单体中的碳碳双键和/或环氧基进行交联聚 合反应得到的。
根据本公开的实施方式，所述交联聚合物填充于正极片的空隙中、负极片的空隙中和隔膜的空隙中。
根据本公开的实施方式，所述交联聚合物具有三维网络结构，液态电解液(电池制备过程中注入的液态电解液)填充在所述三维网络结构的空隙中，形成凝胶电解质或固态电解质。
根据本公开的实施方式，所述电池是一种准固态电池。
根据本公开的实施方式，作为一种示例性说明，所述交联聚合物具有式2所示的结构单元：
式2中，M、X、R1和R2的定义如上所述；R4、R5相同或不同，彼此独立地选自H或者C1～6的烷基；R为有机基团；m为1～1000之间的整数；n为1～500之间的整数。
在一实例中，所述m为300～800之间的整数。
在一实例中，所述n为100～300之间的整数。
根据本公开的实施方式，所述R为含有碳碳双键和/或环氧基的聚合单体聚合之后的基团。
根据本公开的实施方式，所述含有碳碳双键和/或环氧基的聚合单体中的环氧基例如是环氧丙基、环氧丁基、环氧戊基、二氧六环基、二氧五环基、四氢呋喃基。
根据本公开的实施方式，所述含有碳碳双键和/或环氧基的聚合单体具有式3 所示化合物、式4所示化合物、式5所示化合物中的至少一种：
R6R7C＝CR8(R-环氧基)   式3
R9R10C＝CR11(RCR12＝CR13R14)   式4
环氧基-R-环氧基   式5
R为有机基团；R6～R14相同或不同，彼此独立地选自H或者C1～6的烷基(优选为H或者C1～3的烷基，如H或者CH3)。
根据本公开的实施方式，所述含有碳碳双键和/或环氧基的聚合单体例如选自如下化合物中的至少一种：季戊四醇四丙烯酸酯、三羟甲基丙烷三甲基丙烯酸酯、乙氧基化三羟甲基丙烷三丙烯酸酯、新戊二醇二丙烯酸酯、1,5-戊二醇二丙烯酸酯、3-(丙烯酰氧基)-2-羟基丙基甲基丙烯酸酯、丙烯酸缩水甘油酯、3-(烯丙氧基)氧杂环丁烷、甲基丙烯酸氧杂环丁烷酯、甲基丙烯酸缩水甘油酯、四氢糠基丙烯酸酯、1,6-二(丙烯酰氧基)-2,2,3,3,4,4,5,5-八氟己烷。
根据本公开的实施方式，上述聚合单体的结构式如下所述：

本公开还提供一种上述电池的制备方法，其包括如下步骤：
(a)包括有机酸单体的接枝物溶解于有机溶剂中，得到溶液；
(b)在步骤(a)的溶液中加入三元材料，反应，得到分散液；
(c)在步骤(b)的分散液中加入导电剂、粘结剂，充分混合后涂布在集流体表面，干燥后得到所述正极片；
(d)将步骤(c)的正极片、负极片与隔膜组装成电池，然后注入含有碳碳双键和/或环氧基的聚合单体和引发剂的电解液，固化，制备得到所述电池。
根据本公开的实施方式，所述步骤(c)具体包括如下步骤：在步骤(b)的分散液中加入导电剂、粘结剂，充分混合后涂布，再在100℃下烘烤除去溶剂，然后再在100℃下真空干燥进一步除去溶剂，制备得到正极片。
根据本公开的实施方式，所述有机酸单体的含量为三元材料总质量的0.2wt％～2wt％，优选0.4wt％～1.5wt％，更优选0.5wt％～1wt％。
根据本公开的实施方案，所述含有碳碳双键和/或环氧基的聚合单体的含量为电解液总质量的0.2wt％～10wt％，优选为0.5wt％～7wt％，更优选为2wt％～5wt％。
根据本公开的实施方案，所述含有碳碳双键和/或环氧基的聚合单体的含量为三元材料总质量的0.5wt％～8wt％，优选为1wt％～5wt％，更优选为1.5wt％～4wt％。
根据本公开的实施方案，所述引发剂为自由基引发剂，包括但不限于偶氮二异丁腈、偶氮二异庚腈、偶氮二异丁酸二甲酯、过氧化苯甲酰、过氧化二碳酸二异丙酯和过氧化苯甲酸叔丁酯等，其添加量为含有碳碳双键和/或环氧基的聚合单 体总质量的0.5wt％～3wt％。
下文将结合具体实施例对本公开做更进一步的详细说明。应当理解，下列实施例仅为示例性地说明和解释本公开，而不应被解释为对本公开保护范围的限制。凡基于本公开上述内容所实现的技术均涵盖在本公开旨在保护的范围内。
下述实施例中所使用的实验方法如无特殊说明，均为常规方法；下述实施例中所用的试剂、材料等，如无特殊说明，均可从商业途径得到。
实施例1
正极片的制备：
将1质量份的2-丙烯酰胺基-2-甲基丙磺酸(AMPS)溶解在50质量份NMP中，在加入96质量份的NCM811(LiNi0.8Co0.1Mn0.1O2厦门钨业)充分搅拌混合后加入2质量份的导电剂炭黑、1质量份的粘结剂PVDF(聚偏氟乙烯)充分混合均匀配制成NCM811正极浆料，并涂布在厚度为10μm的铝箔表面，然后在80℃下烘干溶剂后再在100℃下真空干燥、经过40吨压力下辊压，压实密度为3.4～4.2g/cm3，得到正极片。
负极片的制备：
将97质量份的石墨负极材料(贝特瑞新能源科技有限公司人造石墨，型号S360-L2-H，比容量357mAh/g)、1.5质量份的炭黑导电剂、1.0质量份的SBR粘结剂(丁苯橡胶)、0.5质量份的羧甲基纤维素以及100质量份的溶剂水，通过双行星搅拌机在真空下以公转30r/min、自转1500r/min的条件搅拌4h，分散成均匀的浆料，并涂布在厚度为6μm的铜箔表面，然后在110℃下烘干、40吨压力下辊压，最后切成所需尺寸的负极片，其中，负极片的面密度为9.4mg/cm2，极片压实密度为1.78g/cm3。
准固态电池的制备：
将上述正极片、负极片、聚乙烯(PE)多孔隔膜(上海恩捷新材料科技有限公司生产的湿法隔膜ND12，厚度12μm)通过卷绕的方式组装、然后注入电解液(深圳新宙邦科技股份有限公司的LBC445B33型号电解液)，该电解液中包括：占电解液质 量2％的三羟甲基丙烷三甲基丙烯酸酯(聚合单体)以及占聚合单体质量1％的AIBN引发剂(偶氮二异丁腈)，制备得到电池。将制备得到的电池经过48h陈化后，再在80℃下热压固化3h得到准固态电池。
实施例2
正极片的制备：与实施例1不同之处在于，将1.5质量份的2-丙烯酰胺基-2-甲基丙磺酸溶解在50质量份NMP中，在加入95.5质量份的NCM811。其他过程与实施例1相同。
负极片制备：与实施例1相同。
电池制备：与实施例相同，不同之处在于注入的电解液中含有5wt％的1,5-戊二醇二丙烯酸酯，以及占聚合单体质量1％的AIBN引发剂。
实施例3
正极片的制备：与实施例1不同之处在于，将0.5质量份的2-丙烯酰胺基-2-甲基丙磺酸溶解在50质量份NMP中，在加入96.5质量份的NCM811。其他过程与实施例1相同。
负极片制备：与实施例1相同。
电池制备：与实施例1相同，不同之处在于注入的电解液中含有1wt％的3-(烯丙氧基)氧杂环丁烷，以及占聚合单体质量1％的AIBN引发剂。
实施例4
正极片的制备：与实施例1不同之处在于，将0.8质量份的2-丙烯酰胺基-2-甲基丙磺酸溶解在50质量份NMP中，在加入96.2质量份的NCM811。其他过程与实施例1相同。
负极片制备：与实施例1相同。
电池制备：与实施例相同，不同之处在于注入的电解液中含有0.5wt％的季戊四醇四丙烯酸酯，以及占聚合单体质量1％的AIBN引发剂。
实施例5
正极片的制备：
将1质量份的乙烯膦酸溶解在50质量份NMP中，在加入96质量份的NCM811(厦门钨业)充分搅拌混合后加入2质量份的导电剂炭黑、1质量份的粘结剂PVDF充分混合均匀配制成NCM811正极浆料，并涂布在10μm铝箔表面，然后在80℃下烘干溶剂后再在100℃下真空干燥、经过40吨压力下辊压，压实密度为3.4～4.2g/cm3，得到正极片。
负极片：制备与实施例1相同。
电池制备：
将上述正极片、负极片、聚乙烯(PE)多孔隔膜(上海恩捷新材料科技有限公司生产的湿法隔膜ND12，厚度12μm)通过卷绕的方式组装、然后注入电解液(深圳新宙邦科技股份有限公司的LBC445B33型号电解液)，该电解液中包括：占电解液质量5％的1,5-戊二醇二丙烯酸酯(聚合单体)以及占聚合单体质量1％的AIBN引发剂，制备得到电池。将制备得到的电池经过48h陈化后再在80℃下热压固化3h得到准固态电池。
实施例6
正极片的制备：与实施例5不同之处在于，将1.5质量份的乙烯膦酸溶解在50质量份NMP中，在加入95.5质量份的NCM811。其他过程与实施例5相同。
负极片制备：与实施例5相同。
电池制备：与实施例5相同。
实施例7
正极片的制备：与实施例5不同之处在于，将0.5质量份的乙烯膦酸溶解在50质量份NMP中，在加入96.5质量份的NCM811。其他过程与实施例5相同。
负极片制备：与实施例5相同。
电池制备：与实施例5相同。
实施例8
正极片的制备：与实施例5不同之处在于，将0.8质量份的乙烯膦酸溶解在50质量份NMP中，在加入96.2质量份的NCM811。其他过程与实施例5相同。
负极片制备：与实施例5相同。
电池制备：与实施例5相同。
实施例9
正极片的制备：与实施例5不同之处在于，将1质量份的丙烯酸溶解在50质量份NMP中，在加入96质量份的NCM811。其他过程与实施例5相同。
负极片制备：与实施例5相同。
电池制备：与实施例5不同之处在于注入添加2％电解液质量的1,5-戊二醇二丙烯酸酯以及1％单体质量的AIBN引发剂的电解液。
实施例10
正极片的制备：与实施例5不同之处在于，将1.5质量份的丙烯酸溶解在50质量份NMP中，在加入95.5质量份的NCM811。其他过程与实施例5相同。
负极片制备：与实施例5相同。
电池制备：与实施例5不同之处在于注入添加含有电解液质量2％的1,5-戊二醇二丙烯酸酯，以及占聚合单体质量1％的AIBN引发剂的电解液。
实施例11
正极片的制备：与实施例5不同之处在于，将0.5质量份的丙烯酸溶解在50质量份NMP中，再加入96.5质量份的NCM811。其他过程与实施例5相同。
负极片制备：与实施例5相同。
电池制备：与实施例5不同之处在于注入添加含有电解液质量2％的1,5-戊二醇二丙烯酸酯,以及占聚合单体质量1％的AIBN引发剂的电解液。
实施例12
正极片的制备：与实施例5不同之处在于，将0.8质量份的丙烯酸溶解在50质量份NMP中，在加入96.2质量份的NCM811。其他过程与实施例5相同。
负极片制备：与实施例5相同。
电池制备：与实施例5不同之处在于注入添加含有电解液质量2％的1,5-戊二醇二丙烯酸酯，以及占聚合单体质量1％的AIBN引发剂的电解液。
对比例1
正极片的制备：与实施例1不同之处在于正极材料为未处理的NCM811(厦门钨业)97质量份。
负极片制备：与实施例1相同。
电池制备：与实施例1相同。
对比例2
正极片的制备：与实施例1不同之处在于正极材料为表面包覆有1％质量分数氧化铝的NCM811(厦门钨业)97质量份。
负极片制备：与实施例1相同。
电池制备：与实施例1相同。
对比例3
正极片的制备：与实施例1不同之处在于加入1质量份的聚丙烯酸(PAA)代替2-丙烯酰胺基-2-甲基丙磺酸单体。
负极片制备：与实施例1相同。
电池制备：与实施例1相同。
对比例4
正极片的制备：与实施例1不同之处在于加入1质量份的PVDF-HFP(聚偏氟乙烯-六氟丙烯2500阿科玛)代替2-丙烯酰胺基-2-甲基丙磺酸单体。
负极片制备：与实施例1相同。
电池制备：与实施例1相同。
测试方法：
电池鼓气率：每100只电池在循环完500圈后发生鼓气的数量占比。
循环寿命测试方法：参考GB/T18287-2013标准测试电池的循环性能取循环500次后的容量保持率，其中循环测试条件为：25℃、0.5C/0.5C充放电(上限电压设置为4.3V，下限电压2.75V)。
表1实施例和对比例的电池的组成和性能测试结果
从鼓气率可以看出，与对比例相比，有机酸单体与三元材料反应后获得的正极活性材料原位组装成电池后的鼓气率明显改善，循环容量保持率也有较大提升。
以上，对本公开的实施方式进行了说明。但是，本公开不限定于上述实施方式。凡在本公开的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本公开的保护范围之内。

Claims (15)

  1. 一种正极活性材料，其特征在于，所述正极活性材料包括三元材料及三元材料表面接枝物，和/或接枝改性的三元材料，所述接枝物包括有机酸单体。
  2. 根据权利要求1所述的正极活性材料，其特征在于，所述有机酸单体包括端烯基和酸官能团；
    优选地，所述酸官能团选自羧基-C(＝O)OH、磷酸基-P(＝O)(OH)2或磺酸基-S(＝O)(＝O)OH。
  3. 根据权利要求1或2所述的正极活性材料，其特征在于，所述有机酸单体包括至少一种式1所示的化合物：
    式1中，R1为不存在或C1～10的亚烷基、C6～14的亚芳基、-CONH-C1～10的亚烷基；R2为H或者C1～6的烷基；R3为羧基、膦酸基或磺酸基。
  4. 根据权利要求3所述的正极活性材料，其特征在于，式1中，R1为不存在或C1～6的亚烷基、C6～12的亚芳基、-CONH-C1～6的亚烷基；R2为H或者C1～3的烷基；R3为-COOH(-C(＝O)OH)、-PO3H2(-P(＝O)(OH)2)或-SO3H(-S(＝O)(＝O)OH)；
    优选地，R1为不存在或C1～3的亚烷基、C6～8的亚芳基、-CONH-C1～3的亚烷基；R2为H或者甲基。
  5. 根据权利要求1-4中任一项所述的正极活性材料，其特征在于，所述有机酸单体包括下列化合物中的一种或多种：丙烯酸、乙烯基乙酸、乙烯基丙酸、乙烯基丁酸、庚-6-烯酸、乙烯基戊酸、甲基丙烯酸、2-丙烯酰胺基-2-甲基丙磺酸、对 苯乙烯磺酸、对苯乙烯甲酸、乙烯膦酸。
  6. 根据权利要求1-5中任一项所述的正极活性材料，其特征在于，所述正极活性材料中，接枝物的质量占正极活性材料总质量的0.2wt％～2wt％，优选为0.4wt％～1.5wt％，更优选为0.5wt％～1wt％。
  7. 根据权利要求1-6中任一项所述的正极活性材料，其特征在于，所述正极活性材料具有下述所示的结构中的一种：
    其中，M为Ni、Co或Mn、R1和R2的定义如上所述，X为*-C(＝O)O-、*-P(＝O)(OH)O-、*-S(＝O)(＝O)O，*端与R1相连；n’为大于等于1的整数，代表的是接枝数。
  8. 根据权利要求1-7中任一项所述的正极活性材料，其特征在于，所述三元材料的化学式为LiaNixCoyM’1-x-yAkO2，其中，0<x<1，0<y<1，0<x+y<1，0.9≤a≤1.1，0≤k≤0.1，M’为Mn或Al，A为选自以下元素的掺杂剂：Co、Cu、Zn、Fe、Al、Mg、Ti、Zr、Y、B、La、Mo、Nb、P、Mn或其组合；
    优选地，所述三元材料包括具有层状结构的镍钴铝三元材料和/或层状结构的镍钴锰三元材料；
    优选地，所述镍钴铝三元材料的化学式为LiaNixCoyAl1-x-yAkO2，0<x<1，0<y<1，0<x+y<1，0.9≤a≤1，0≤k≤0.1，A为选自以下元素的掺杂剂：Co、Cu、Zn、Fe、Al、Mg、Ti、Zr、Y、B、La、Mo、Nb、P、Mn或其组合；
    优选地，所述镍钴锰三元材料的化学式为LiaNixCoyMn1-x-yAkO2，0<x<1，0<y<1，0<x+y<1，0.9≤a≤1，0≤k≤0.1，A为选自以下元素的掺杂剂：Co、Cu、Zn、Fe、Al、Mg、Ti、Zr、Y、B、La、Mo、Nb、P、Mn或其组合。
  9. 一种正极片，其特征在于，所述正极片包括权利要求1-8任一项所述的正极活性材料。
  10. 根据权利要求9所述的正极片，其特征在于，所述正极片包括集流体和位于集流体至少一侧表面的正极活性层，所述正极活性层中包括所述的正极活性材料；
    优选地，所述正极活性层还包括导电剂和粘结剂；
    优选地，所述正极活性层中各组分的质量百分含量为：91wt％～97.5wt％的所述正极活性材料、0.5wt％～4wt％的导电剂、2wt％～5wt％的粘结剂。
  11. 一种电池，其特征在于，所述电池包括权利要求1-8中任一项所述的正极活性材料，或权利要求9或10所述的正极片；
    优选地，所述电池还包括电解质，所述电解质中含有交联聚合物，所述交联聚合物中含有碳碳双键和/或环氧基。
  12. 根据权利要求11所述的电池，其特征在于，含有碳碳双键和/或环氧基的聚合单体的含量为正极活性材料中三元材料总质量的0.5wt％～8wt％，优选为1wt％～5wt％，更优选为1.5wt％～4wt％；
    优选地，所述交联聚合物是所述正极活性材料与含有碳碳双键和/或环氧基的聚合单体的交联聚合物。
  13. 根据权利要求11或12所述的电池，其特征在于，所述交联聚合物具有式2所示的结构单元：
    式2中，M、X、R1和R2的定义如上所述；R4、R5相同或不同，彼此独立地选自H或者C1～6的烷基；R为有机基团；m为1～1000之间的整数；n为1～500之间的整数。
  14. 根据权利要求12或13所述的电池，其特征在于，所述含有碳碳双键和/或环氧基的聚合单体具有式3所示化合物、式4所示化合物、式5所示化合物中的至少一种：
    R6R7C＝CR8(R-环氧基)   式3
    R9R10C＝CR11(RCR12＝CR13R14)   式4
    环氧基-R-环氧基   式5
    R为有机基团；R6～R14相同或不同，彼此独立地选自H或者C1～6的烷基(优选为H或者C1～3的烷基，更优选为H或者CH3)；环氧基选自环氧丙基、环氧丁基、环氧戊基、二氧六环基、二氧五环基、四氢呋喃基。
  15. 根据权利要求12-14任一项所述的电池，其特征在于，所述含有碳碳双键和/或环氧基的聚合单体选自如下化合物中的至少一种：季戊四醇四丙烯酸酯、三羟甲基丙烷三甲基丙烯酸酯、乙氧基化三羟甲基丙烷三丙烯酸酯、新戊二醇二丙烯酸酯、1,5-戊二醇二丙烯酸酯、3-(丙烯酰氧基)-2-羟基丙基甲基丙烯酸酯、丙烯酸缩水甘油酯、3-(烯丙氧基)氧杂环丁烷、甲基丙烯酸氧杂环丁烷酯、甲基丙烯酸缩水甘油酯、四氢糠基丙烯酸酯、1,6-二(丙烯酰氧基)-2,2,3,3,4,4,5,5-八氟己烷。
PCT/CN2023/093273 2022-05-27 2023-05-10 正极活性材料及包括该正极活性材料的正极片和电池 WO2023226765A1 (zh)

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007305453A (ja) * 2006-05-12 2007-11-22 Nec Tokin Corp リチウムイオンポリマー電池
US20110151325A1 (en) * 2009-12-23 2011-06-23 Gue-Sung Kim Cathode active material, cathode including the cathode active material, lithium battery including the cathode, and method of preparing the cathode active material
CN107958997A (zh) * 2016-10-14 2018-04-24 宁德新能源科技有限公司 正极浆料、正极极片及锂离子电池
CN112786832A (zh) * 2021-01-25 2021-05-11 湖南立方新能源科技有限责任公司 一种负极片及锂离子电池
CN113937249A (zh) * 2021-09-30 2022-01-14 惠州亿纬集能有限公司 高镍三元正极浆料及其制备方法、正极极片、锂离子电池
CN114023965A (zh) * 2021-10-28 2022-02-08 深圳新宙邦科技股份有限公司 固态锂电池
CN114335716A (zh) * 2021-12-31 2022-04-12 北京卫蓝新能源科技有限公司 一种具有多层结构电解质的原位聚合固态电池及其制备方法
CN115000401A (zh) * 2022-05-27 2022-09-02 珠海冠宇电池股份有限公司 一种正极活性材料及包括该正极活性材料的正极片和电池

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007305453A (ja) * 2006-05-12 2007-11-22 Nec Tokin Corp リチウムイオンポリマー電池
US20110151325A1 (en) * 2009-12-23 2011-06-23 Gue-Sung Kim Cathode active material, cathode including the cathode active material, lithium battery including the cathode, and method of preparing the cathode active material
CN107958997A (zh) * 2016-10-14 2018-04-24 宁德新能源科技有限公司 正极浆料、正极极片及锂离子电池
CN112786832A (zh) * 2021-01-25 2021-05-11 湖南立方新能源科技有限责任公司 一种负极片及锂离子电池
CN113937249A (zh) * 2021-09-30 2022-01-14 惠州亿纬集能有限公司 高镍三元正极浆料及其制备方法、正极极片、锂离子电池
CN114023965A (zh) * 2021-10-28 2022-02-08 深圳新宙邦科技股份有限公司 固态锂电池
CN114335716A (zh) * 2021-12-31 2022-04-12 北京卫蓝新能源科技有限公司 一种具有多层结构电解质的原位聚合固态电池及其制备方法
CN115000401A (zh) * 2022-05-27 2022-09-02 珠海冠宇电池股份有限公司 一种正极活性材料及包括该正极活性材料的正极片和电池

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