WO2023169096A1 - Matériau actif d'électrode positive, batterie secondaire, module de batterie, bloc-batterie et dispositif électrique - Google Patents

Matériau actif d'électrode positive, batterie secondaire, module de batterie, bloc-batterie et dispositif électrique Download PDF

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WO2023169096A1
WO2023169096A1 PCT/CN2023/073929 CN2023073929W WO2023169096A1 WO 2023169096 A1 WO2023169096 A1 WO 2023169096A1 CN 2023073929 W CN2023073929 W CN 2023073929W WO 2023169096 A1 WO2023169096 A1 WO 2023169096A1
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formula
active material
cathode active
compound represented
secondary battery
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PCT/CN2023/073929
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English (en)
Chinese (zh)
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吴则利
韩昌隆
郭洁
黄磊
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宁德时代新能源科技股份有限公司
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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
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • 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
    • 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
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • 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
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • 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
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • 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
    • 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
    • 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
    • H01M4/602—Polymers
    • H01M4/606—Polymers containing aromatic main chain polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/249—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders specially adapted for aircraft or vehicles, e.g. cars or trains
    • 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

Definitions

  • the present application relates to the field of battery technology, and more specifically, to positive active materials, secondary batteries and electrical devices.
  • Secondary batteries have the advantages of reliable working performance, no pollution, and no memory effect, so they are widely used. For example, as environmental protection issues become more and more important and new energy vehicles become more popular, the demand for power secondary batteries will grow explosively. However, as the application range of secondary batteries becomes more and more extensive, severe challenges are also posed to the performance of secondary batteries.
  • a positive electrode active material of a secondary battery for example, a transition metal oxide having a spinel structure, a layered structure, or a lithium-rich manganese base is used. When these positive electrode active materials are used, lower resistance and higher power of the positive electrode active material are expected.
  • the present application provides a cathode active material, a secondary battery and an electrical device.
  • the application can achieve low resistance and high power of the cathode active material.
  • this application proposes a cathode active material.
  • the cathode active material includes: an active component; and a coating layer containing an organic component, which covers at least part of the surface of the active component.
  • the organic component Including compounds represented by formula (1) and/or polymers formed by cross-linking polymerization of compounds represented by formula (1),
  • M is selected from a phosphorus atom, a boron atom or a sulfur atom
  • R is selected from an oxygen atom, a C1-C20 alkoxy group, a substituted or unsubstituted C6-C25 aromatic phenol group and a substituted or unsubstituted One or more C5-C25 heteroaromatic phenol groups
  • n represents the number of R groups, n is selected from 2 or 3.
  • the coating layer of the present application covers the surface of the active material, and the M atoms in the coating layer can interact with the oxygen atoms in the active material to stabilize the oxygen atoms and ensure the crystal lattice of the active component. Stability, and oxygen atoms are not easy to escape from the crystal lattice and cause side reactions with the electrolyte, thereby making the overall structural stability of the cathode active material better, thereby improving the cycle performance and capacity performance of the secondary battery; and stabilizing the cathode activity
  • the contact interface between the material and the electrolyte, the positive electrode solid electrolyte interface film CEI film formed on the surface of the positive electrode active material has better stability, resulting in better dynamic performance; M atoms may coordinate with fluorine ions in the electrolyte reaction, thereby effectively suppressing the generation of passivation material LiF, thereby reducing the DC impedance of the secondary battery, thereby improving the power performance of the secondary battery.
  • the active component includes at least one of the following components: Li s T q Ni a Co b Mn c M (1- abc) Y t , where 0 ⁇ s ⁇ 2.1, 0 ⁇ q ⁇ 2.1, and 0.9 ⁇ s+q ⁇ 2.1; 0 ⁇ a ⁇ 1, 0 ⁇ b ⁇ 1, 0 ⁇ c ⁇ 1, and 0.1 ⁇ a+b+c ⁇ 1; 1.8 ⁇ t ⁇ 3.5; T is selected from Na , one or more of K and Mg; M is selected from B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Fe, Cu, Zn, Sr, Y, Zr, Nb , one or more of Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, and Ce; Y is selected from one or more of O and F; xLi 2 MnO 3 ⁇ ( 1-x)LiMn y B 1-y O 2 , where, 0.1 ⁇ x ⁇ 0.9, 0.1 ⁇
  • M includes a phosphorus atom
  • the compound represented by formula (1) includes compounds represented by formula (I) and/or formula (II):
  • R 1 , R 2 , R 3 and R 4 are each independently selected from a hydrogen atom, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C6- C25 aryl, or substituted or unsubstituted C5-C25 heteroaryl; optionally, R 1 , R 2 , R 3 and R 4 are each independently selected from C1-C3 alkyl, phenyl, naphthyl , anthracenyl, phenanthrenyl, diphenyl or terphenyl.
  • the phosphorus atoms in this application interact with the oxygen in the active component to stabilize the cathode interface and improve the dynamics, and the phosphorus ions can coordinate with the fluoride ions in the electrolyte, effectively Suppresses the generation of passivation material LiF, thereby improving DC impedance. This can improve the power characteristics and cycle characteristics of the secondary battery.
  • the compound represented by formula (I) includes one or more compounds represented by formula (P-11) to formula (P-16):
  • Compounds represented by formula (II) include compounds represented by formula (P-21) and/or formula (P-22):
  • M includes a boron atom
  • the compound represented by formula (1) includes a compound represented by formula (III):
  • R 6 and R 7 are each independently selected from a hydrogen atom, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C6-C25 aryl group, or a substituted or unsubstituted C1-C25 aryl group.
  • the interaction between boron atoms and oxygen in the active component can stabilize the cathode interface and improve kinetics. Boron ions can coordinate with fluoride ions in the electrolyte to effectively suppress the generation of passivation LiF, thereby improving DC impedance. This can improve the power characteristics and cycle characteristics of the secondary battery.
  • the compound represented by formula (III) includes compounds represented by formula (B-1) to formula (B-3).
  • M includes a sulfur atom
  • the compound represented by formula (1) includes a compound represented by formula (IV):
  • R 5 is selected from a hydrogen atom, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C6-C25 aryl group, or a substituted or unsubstituted C5-C25 heteroaromatic group. group; optionally, each R 5 is independently selected from C1-C3 alkyl, phenyl, naphthyl, anthracenyl, phenanthrenyl, diphenyl or terphenyl.
  • Sulfur atoms interact with oxygen in the active component to stabilize the cathode interface and improve dynamics.
  • Boron ions can coordinate with fluoride ions in the electrolyte to effectively suppress the generation of passivation LiF, thereby improving DC impedance. This can improve the power characteristics and cycle characteristics of the secondary battery.
  • the compound represented by formula (IV) includes compounds represented by formula (S-1) and/or formula (S-2):
  • the coating layer includes a polymer formed by cross-linking polymerization of the compound represented by formula (1); the weight average molecular weight of the polymer is 500 Da to 2000 Da; optionally 1000 Da to 1500 Da; and/or coating The porosity of the layer ranges from 5% to 20%.
  • the weight average molecular weight of the polymer is within the above range, the viscosity of the coating layer formed by the polymer is relatively high, and its binding strength with the active component is relatively strong.
  • the coating layer is not easily It falls off from the surface of the active component, thereby providing long-term and stable protection to the active component and ensuring the cycle performance and capacity performance of the secondary battery.
  • the viscosity of the coating layer formed by the polymer will not be too high, the coating layer formed by it is easier to control, the thickness of the coating layer is more uniform, and the protective performance against active components is uniform.
  • the compound represented by formula (1) forms a polymer through cross-linking, the polymer may have a pore structure, so that the coating layer formed by the polymer has certain pores. The existence of these pores is conducive to the escape of active ions or embedded, Reduce DC impedance and improve dynamic performance.
  • the mass content of the organic component in the cathode active material is recorded as A%, 0.1 ⁇ A ⁇ 0.5; optionally, 0.2 ⁇ A ⁇ 0.4; and/or
  • the thickness of the cladding layer is 5 ⁇ m to 20 ⁇ m; optionally 5 ⁇ m to 10 ⁇ m.
  • the content of the organic component is within the above range.
  • the organic component can fully protect the active components and improve the cycle performance and capacity performance of the secondary battery; on the other hand, the organic component can make the package formed
  • the thickness of the coating layer is not too thick and the dynamic properties are improved, thereby further improving the power characteristics and cycle characteristics of the secondary battery.
  • a second aspect of the present application provides a secondary battery.
  • the secondary battery includes: a positive electrode plate, a negative electrode plate, an isolation film disposed between the positive electrode plate and the negative electrode plate, and an electrolyte.
  • the positive electrode plate includes The cathode active material as described in any embodiment of the first aspect of the application.
  • the electrolyte includes a first additive configured to form a film on the surface of the cathode active material, wherein the first additive includes an oxygen-containing heterocyclic element having at least one heterocyclic element among sulfur, phosphorus, and boron.
  • Ring compounds, and oxygen-containing heterocyclic compounds include mirror-image structures symmetrical with carbon-carbon single bonds. Therefore, the first additive in this application is a specific molecule with a symmetrical structure. These molecules can first be oxidized to form a film on the surface of the cathode active material in preference to the solvent of the electrolyte. Secondly, these molecules will also be physically adsorbed on the surface of the cathode active material.
  • the adsorption film formation has good uniformity and consistency, which can improve problems such as gas production during high-temperature storage of positive electrode active materials, and further improve cycle characteristics.
  • the surface of the positive active material is a coating layer, the coating layer is conducive to the adsorption of the first additive, further improving the film-forming effect of the first additive.
  • the first additive can also form a film on the surface of the negative electrode active material, which can also improve the film-forming performance on the surface of the negative electrode active material, thereby further improving the cycle characteristics of the secondary battery.
  • the first additive includes one or more compounds represented by formula (2) to formula (5):
  • the mass content of the organic component in the cathode active material is recorded as A%; based on the total mass of the electrolyte, the mass content of the first additive in the electrolyte is expressed as is B%, where the secondary battery satisfies: 0.5 ⁇ B/A ⁇ 2. Therefore, the first additive in the electrolyte of the present application and the organic components in the cathode active material cooperate with each other, which is beneficial to forming a uniform and dense CEI film on the surface of the cathode active material, and acts on the active components in the cathode active material.
  • the mass content of the first additive in the electrolyte is recorded as B%, and 0.10 ⁇ B ⁇ 0.70.
  • the first additive includes at least two of the compounds represented by formula (2) to formula (5); based on the total molar amount of the first additive, one of the compounds in the first additive
  • the ratio of the molar content of the compound to the molar content of another compound is recorded as C, 1 ⁇ C ⁇ 2; optionally, 1.2 ⁇ C ⁇ 1.5. Therefore, this application can make the CEI film formed by the first additive on the surface of the positive electrode active material richer in components through the cooperation of the two compounds, and the structure of the CEI film is more stable, and is conducive to the embedding or embedding of active ions. out, thereby improving the cycle performance of the secondary battery.
  • the first additive may also be able to form a component-rich SEI film on the surface of the negative electrode active material, thereby further improving the cycle performance of the secondary battery.
  • This application proposes an electrical device, including a secondary battery as described in any embodiment of the second aspect of this application.
  • FIG. 1 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • FIG. 2 is an exploded view of the secondary battery according to the embodiment of the present application shown in FIG. 1 .
  • FIG. 3 is a schematic diagram of a battery module according to an embodiment of the present application.
  • Figure 4 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 5 is an exploded view of the battery pack according to an embodiment of the present application shown in FIG. 4 .
  • FIG. 6 is a schematic diagram of a power consumption device using a secondary battery as a power source according to an embodiment of the present application.
  • Ranges disclosed herein are defined in terms of lower and upper limits. A given range is defined by selecting a lower limit and an upper limit that define the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive of the endpoints, and may be arbitrarily combined, that is, any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, understand that ranges of 60-110 and 80-120 are also expected. Additionally, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5.
  • the numerical range “ab” represents an abbreviated representation of any combination of real numbers between a and b, where a and b are both real numbers.
  • the numerical range “0-5" means that all real numbers between "0-5" have been listed in this article, and "0-5" is just an abbreviation of these numerical combinations.
  • a certain parameter is an integer ⁇ 2
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially.
  • step (c) means that step (c) may be added to the method in any order.
  • the method may include steps (a), (b) and (c). , may also include steps (a), (c) and (b), may also include steps (c), (a) and (b), etc.
  • condition "A or B” is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists) ; Or both A and B are true (or exist).
  • alkoxy refers to a group in which an alkyl group is bonded to an oxygen atom by a single bond.
  • the alkoxy group can be C1-C20 alkoxy, C1-C15 alkoxy, C1-C10 alkoxy, C1-C8 alkoxy, C1-C5 alkoxy, C2-C6 alkoxy.
  • alkoxy can include methoxy, ethoxy, propoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, cyclobutoxy, pentoxy , isopentyloxy, neopentyloxy, tert-pentyloxy, cyclopentyloxy.
  • aryl refers to a closed aromatic ring or ring system.
  • the aryl group can be C6-C50 aryl, C6-C40 aryl, C6-C30 aryl, C6-C20 aryl, C6-C10 aryl, where C6-C30 aryl refers to a group containing 6-30 aryl groups. Carbon atoms that form a ring.
  • aryl groups include phenyl, naphthyl, phenanthrenyl, anthracenyl, biphenyl, triphenylene, pyrenyl, spirobifluorenyl, perylene, indenyl, azulenyl, and the like.
  • aromatic heterocyclyl means that the carbon atoms in the ring of the aryl group are replaced by heteroatoms.
  • the heteroatoms may include nitrogen atoms, oxygen atoms, sulfur atoms, etc.
  • aromatic phenol group refers to a group formed by combining a carbon atom in the square ring of an aryl group with a hydroxyl group.
  • the aromatic phenol group can be a C6-C25 aromatic phenol group, a C6-C20 aromatic phenol group, a C6-C15 aromatic phenol group, or a C6-C10 aromatic phenol group.
  • the aromatic phenol group may include phenyl hydroxyl, naphthyl hydroxyl, phenanthrene hydroxyl, anthracene hydroxyl, biphenyl hydroxyl, triphenylene hydroxyl, pyrene hydroxyl, spirobifluorene hydroxyl, perylene hydroxyl, indene hydroxyl, azulene hydroxyl, and the like.
  • heteromatic phenol group means that the carbon atoms in the square ring are replaced by heteroatoms.
  • the heteroatoms can include nitrogen atoms, oxygen atoms, sulfur atoms, etc.
  • the heteroaromatic phenol group may include azobenzene hydroxyl, azonaphthalene Hydroxy, azazaphenanthrene hydroxyl, azoanthracene hydroxyl, azabiphenyl hydroxyl, azatriphenylene hydroxyl, azapyrene hydroxyl, azaspirobifluorene hydroxyl, azaperylene hydroxyl, azaindene hydroxyl, azazazulene hydroxyl , heterothiophenyl hydroxyl, heterothionaphthalene hydroxyl, heterothiophenanthrene hydroxyl, heterothionthane hydroxyl, heterothiobiphenyl hydroxyl, heterooxyphenyl hydroxyl, heterooxynaphthyl hydroxyl,
  • the substituent may be a halogen atom or the like.
  • the stability of its material structure has a direct impact on the performance of secondary batteries.
  • oxygen atoms are easily detached from the lattice position, resulting in instability of the lattice structure; and the detached oxygen atoms have high reactivity and can react with the electrolyte on the surface of the positive active material. Side reactions lead to instability of the interface film on the surface of the cathode active material.
  • the structural stability of the cathode active material itself may be poor, especially under high temperature and high pressure systems, it is easy to decompose and release a large amount of oxygen, further deteriorating the performance of the cathode active material. Secondary batteries using this type of cathode active material have poor cycle performance and rapid capacity fading.
  • this application starts from the perspective of protecting the cathode active material, and covers the surface of the cathode active material with a coating layer to stabilize the structure of the cathode active material, improve the cycle performance of the cathode active material, and improve the use of the cathode active material.
  • the cycle performance and capacity performance of the secondary battery of the material can be improved at the same time, and its power performance can be improved at the same time.
  • this application proposes a cathode active material.
  • the cathode active material includes an active component and a coating layer; the coating layer covers at least part of the surface containing the active component and can act on the active component. Excellent protective effect.
  • the coating layer contains organic components, and the organic components include compounds represented by formula (1) and/or polymers formed by cross-linking and polymerization of compounds represented by formula (1),
  • M is selected from a phosphorus atom, a boron atom or a sulfur atom
  • R is selected from one or more of oxygen atoms, C1-C20 alkoxy groups, substituted or unsubstituted C6-C25 aromatic phenol groups, and substituted or unsubstituted C5-C25 heteroaromatic phenol groups;
  • n represents the number of R groups, n is selected from 2 or 3; the value of n depends on the type of atom taken by M.
  • this application can significantly improve the structural stability of the cathode active material by coating the above-mentioned active component with the above-mentioned organic component.
  • the positive electrode active material When used in secondary batteries, it can improve the cycle of the secondary battery. performance and capacity performance, and the ability to improve its power characteristics.
  • Oxygen atoms are usually included in the active ingredients.
  • the coating layer covers the surface of the active material.
  • the M atoms in the coating layer can interact with the oxygen atoms in the active material to stabilize the oxygen atoms and ensure the lattice stability of the active components.
  • the positive electrode solid electrolyte interface film CEI film formed on the surface of the positive electrode active material has better stability, resulting in better dynamic performance; M atoms may undergo coordination reactions with fluorine ions in the electrolyte, which can effectively inhibit The passivation material LiF is generated, thereby reducing the DC resistance of the secondary battery, thereby improving the power performance of the secondary battery.
  • the active component can provide capacity for the secondary battery and may include at least one of the following materials: layered structure cathode active materials (such as ternary, lithium/sodium nickelate, lithium/sodium cobaltate, Materials such as lithium/sodium manganate, lithium/sodium rich layered and rock salt phase layered materials), spinel structure cathode active materials (such as spinel lithium manganate, spinel lithium nickel manganate, lithium-rich spinel Spar lithium manganate and lithium nickel manganate, etc.), olivine type phosphate active materials.
  • the cathode active material may be a layered structure and/or a spinel structure.
  • the general formula of the layered structure cathode active material is: Li s T q Ni a Co b Mn c M (1-abc) Y t , where 0 ⁇ s ⁇ 2.1, 0 ⁇ q ⁇ 2.1, and 0.9 ⁇ s+q ⁇ 2.1; 0 ⁇ a ⁇ 1, 0 ⁇ b ⁇ 1, 0 ⁇ c ⁇ 1, and 0.1 ⁇ a+b+c ⁇ 1; 1.8 ⁇ t ⁇ 3.5; T is selected from Na, K, Mg One or more of them; M is selected from B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Fe, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd , one or more of Sn, Sb, Te, Ba, Ta, W, Yb, La, and Ce; Y is selected from one or more of O and F.
  • the layered structure cathode active material is: LiNi a Co b Mn c Y 2 .
  • the layered structure cathode active material may include lithium cobalt oxide LCO, lithium nickel oxide LNO, lithium manganate LMO, LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM333), LiNi 0.8 Co 0.1 Mn 0.1 One or more of O 2 (NCM811) and LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523).
  • the general formula of the spinel structure cathode active material is: xLi 2 MnO 3 ⁇ (1-x)LiMn y B 1- y O 2 , where, 0.1 ⁇ x ⁇ 0.9, 0.1 ⁇ y ⁇ 0.9, B is selected from Ni, Co, B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Fe, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb , Te, Ba, Ta, W, Yb, La, Ce; optionally, B is selected from one or more of Na, K, Mg.
  • the spinel structure cathode active materials include LiMn 2 O 4 , LiNi 0.5 Mn 1.5 O 4 , LiCr 0.3 Mn 1.7 O 4 , Li 1.1 Al 0.1 Mn 1.9 O 4 , Li 2 Mn 2 O 4 and Li 1.5 Mn One or more of 2 O 4 .
  • the general formula of the olivine-type phosphate active material is: Li x A y Me a M b P 1-c X c Y z , where 0 ⁇ x ⁇ 1.3, 0 ⁇ y ⁇ 1.3, and 0.9 ⁇ x+y ⁇ 1.3; 0.9 ⁇ a ⁇ 1.5, 0 ⁇ b ⁇ 0.5, and 0.9 ⁇ a+b ⁇ 1.5; 0 ⁇ c ⁇ 0.5; 3 ⁇ z ⁇ 5;
  • A is selected from one of Na, K and Mg One or more;
  • Me is selected from one or more of Mn, Fe, Co, and Ni;
  • M is selected from B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Cu, One or more of Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, and Ce;
  • X is selected from S, Si, Cl, B, One or more of C and N;
  • Y is selected from one or more
  • the coating layer covers the surface of the active component. It can cover the entire surface of the active component, so that the active component can be fully protected; it can also cover part of the surface of the active component. This can ensure that the DC impedance of the secondary battery is relatively low on the basis of protecting the active components, which is conducive to both Cycle performance and power characteristics of secondary batteries.
  • the coating layer includes organic components, which can be monomer structures of small molecules or macromolecular polymers formed by cross-linking between monomer structures. The monomer structure of small molecules makes it easier to control the film thickness; the film layer formed by macromolecular polymers is more uniform and dense, and has better protection against active components.
  • R is selected from one of an oxygen atom, a C1-C10 alkoxy group, a substituted or unsubstituted C6-C10 aromatic phenol group, and a substituted or unsubstituted C5-C10 heteroaromatic phenol group.
  • R is selected from C1-C3 alkyl, phenyl, naphthyl, anthracenyl, phenanthrenyl, diphenyl or terphenyl.
  • M includes a phosphorus atom.
  • Phosphorus atoms interact with oxygen in the active component to stabilize the cathode interface and improve dynamics.
  • Phosphorus ions can coordinate with fluoride ions in the electrolyte to effectively inhibit the generation of passivation LiF, thereby improving DC impedance. This can improve the power characteristics and cycle characteristics of the secondary battery.
  • the compounds represented by formula (1) include compounds represented by formula (I):
  • R 1 and R 2 , R 3 and R 4 are each independently selected from a hydrogen atom, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C6-C25 aryl group, or Substituted or unsubstituted C5-C25 heteroaryl;
  • R 1 and R 2 , R 3 and R 4 are each independently selected from C1-C3 alkyl, phenyl, naphthyl, anthracenyl, phenanthrenyl, diphenyl or terphenyl.
  • the compound represented by formula (I) includes one or more compounds represented by formula (P-11) to formula (P-16):
  • the compounds represented by formula (1) include compounds represented by formula (II):
  • R 3 and R 4 are each independently selected from a hydrogen atom, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C6-C25 aryl group, or a substituted or unsubstituted C1-C25 aryl group.
  • C5-C25 heteroaromatic group optionally, R 3 and R 4 are each independently selected from C1-C3 alkyl, phenyl, naphthyl, anthracenyl, phenanthrenyl, diphenyl or terphenyl.
  • the compound represented by formula (I) includes one or more compounds represented by formula (P-21) and formula (P-22):
  • the compound represented by formula (1) includes the compound represented by formula (I) and the compound represented by formula (II).
  • M includes boron atoms.
  • the interaction between boron atoms and oxygen in the active component can stabilize the cathode interface and improve kinetics.
  • Boron ions can coordinate with fluoride ions in the electrolyte to effectively suppress the generation of passivation LiF, thereby improving DC impedance. This can improve the power characteristics and cycle characteristics of the secondary battery.
  • the compounds represented by formula (1) include compounds represented by formula (III):
  • R 6 and R 7 are each independently selected from a hydrogen atom, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C6-C25 aryl group, or a substituted or unsubstituted C1-C25 aryl group.
  • C5-C25 heteroaromatic group optionally, R 6 and R 7 are each independently selected from C1-C3 alkyl, phenyl, naphthyl, anthracenyl, phenanthrenyl, diphenyl or terphenyl.
  • the compound represented by formula (III) includes one or more compounds represented by formula (B-1) to formula (B-3):
  • M includes a sulfur atom.
  • Sulfur atoms interact with oxygen in the active component to stabilize the cathode interface and improve dynamics.
  • Boron ions can coordinate with fluoride ions in the electrolyte to effectively suppress the generation of passivation LiF, thereby improving DC impedance. This can improve the power characteristics and cycle characteristics of the secondary battery.
  • the compounds represented by formula (1) include compounds represented by formula (IV):
  • R 5 is selected from a hydrogen atom, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C6-C25 aryl group, or a substituted or unsubstituted C5-C25 heteroaromatic group. base;
  • R 5 is each independently selected from C1-C3 alkyl, phenyl, naphthyl, anthracenyl, phenanthrenyl, diphenyl or terphenyl.
  • the compounds represented by formula (IV) include compounds represented by formula (S-1) and/or formula (S-2):
  • the inventors of the present application have discovered that when the cathode active material satisfies one or more of the following conditions, the cycle performance, capacity performance and power performance of the secondary battery can be further improved.
  • the polymer has a weight average molecular weight of 500 Da to 2000 Da.
  • the viscosity of the coating layer formed by the polymer is relatively high, and its binding strength with the active component is relatively strong.
  • the coating layer is not easily It falls off from the surface of the active component, thereby providing long-term and stable protection to the active component and ensuring the cycle performance and capacity performance of the secondary battery.
  • the viscosity of the coating layer formed by the polymer will not be too high, the coating layer formed by it is easier to control, the thickness of the coating layer is more uniform, and the protective performance against active components is uniform.
  • the polymer has a weight average molecular weight of 1000 Da to 1500 Da.
  • the weight average molecular weight of the polymer is 500Da, 600Da, 800Da, 900Da, 1000Da, 1200Da, 1500Da, 1800Da, 2000Da or a range consisting of any two of the above values.
  • the cladding layer has a porosity of 5% to 20%.
  • the polymer may have a pore structure, so that the coating layer formed by the polymer has certain pores.
  • the existence of these pores is conducive to the escape of active ions. Or embedded to reduce DC impedance and improve dynamic performance.
  • the porosity of the coating layer can be 5%, 6%, 8%, 10%, 12%, 15%, 16%, 18%, 19%, 20%, or any two of the above values. scope.
  • the mass content of the organic component in the cathode active material is recorded as A%, 0.1 ⁇ A ⁇ 0.5; optionally 0.2 ⁇ A ⁇ 0.4.
  • the content of the organic component is within the above range.
  • the organic component can fully protect the active components and improve the cycle performance and capacity performance of the secondary battery; on the other hand, the organic component can make the package formed
  • the thickness of the coating layer is not too thick and the dynamic properties are improved, thereby further improving the power characteristics and cycle characteristics of the secondary battery.
  • the mass content of the organic component in the cathode active material, recorded as A% can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or a range consisting of any two of the above values.
  • the thickness of the coating layer is 5 ⁇ m to 20 ⁇ m; optionally, the thickness is 5 ⁇ m to 10 ⁇ m.
  • the thickness of the coating layer is within the above range.
  • the organic components can fully protect the active components and improve the cycle performance and capacity performance of the secondary battery.
  • the coating formed by the organic components can The thickness of the coating layer is not too thick and the dynamic properties are improved, thereby further improving the power characteristics and cycle characteristics of the secondary battery.
  • the thickness of the coating layer may be 5 ⁇ m, 6 ⁇ m, 8 ⁇ m, 10 ⁇ m, 12 ⁇ m, 15 ⁇ m, 16 ⁇ m, 18 ⁇ m, 20 ⁇ m, or a range consisting of any two of the above values.
  • the present application provides a secondary battery, which includes a positive electrode plate, a negative electrode plate, a separation film disposed between the positive electrode plate and the negative electrode plate, and an electrolyte
  • the positive electrode sheet includes a positive electrode film layer
  • the positive electrode film layer includes the positive electrode active material as described in any embodiment of the first aspect of this application.
  • the active components in the cathode active material can significantly improve the cycle performance, capacity performance and power performance of the secondary battery through coating with organic components.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector.
  • the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.
  • the positive electrode film layer optionally further includes a positive electrode conductive agent.
  • a positive electrode conductive agent includes superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon.
  • the mass percentage of the cathode conductive agent is less than 5%.
  • the positive electrode film layer optionally further includes a positive electrode binder.
  • the positive electrode binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene. Terpolymers, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymers, tetrafluoroethylene-hexafluoropropylene copolymers and fluorine-containing acrylate resins One or a combination of more.
  • the mass percentage of the cathode binder is less than 5% based on the total mass of the cathode film layer.
  • the positive electrode current collector may be a metal foil or a composite current collector.
  • the metal foil aluminum foil or aluminum alloy foil can be used.
  • the composite current collector may include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer.
  • the metal material may include aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver. and a combination of one or more silver alloys.
  • the polymer material base layer may include polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate ( One or a combination of one or more of PBT), polystyrene (PS) and polyethylene (PE).
  • the positive electrode film layer is usually formed by coating the positive electrode slurry on the positive electrode current collector, drying and cold pressing.
  • the cathode slurry is usually formed by dispersing the cathode active material, optional conductive agent, optional binder and any other components in a solvent and stirring evenly.
  • the solvent may be N-methylpyrrolidone (NMP), but is not limited thereto.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, where the negative electrode film layer includes a negative electrode active material.
  • the negative electrode current collector has two opposite surfaces in its own thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base material.
  • the composite current collector can be formed by forming metal materials (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyterephthalate It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative active material may be a negative active material known in the art for batteries.
  • the negative active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, and the like.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon carbon composites, silicon nitrogen composites and silicon alloys.
  • the tin-based material may be selected from at least one of elemental tin, tin oxide compounds and tin alloys.
  • the present application is not limited to these materials, and other traditional materials that can be used as battery negative electrode active materials can also be used. Only one type of these negative electrode active materials may be used alone, or two or more types may be used in combination.
  • the negative electrode film layer optionally further includes a negative electrode binder.
  • the negative electrode binder can be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), At least one of polymethacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the negative electrode film layer optionally further includes a conductive agent.
  • the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the negative electrode film layer optionally includes other auxiliaries, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
  • thickeners such as sodium carboxymethylcellulose (CMC-Na)
  • the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as negative active materials, conductive agents, binders and any other components in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode piece can be obtained.
  • a solvent such as deionized water
  • the electrolyte plays a role in conducting ions between the positive and negative electrodes.
  • the type of electrolyte in this application can be selected according to needs.
  • the electrolyte can be liquid, gel, or completely solid.
  • the electrolyte is an electrolyte solution.
  • the electrolyte solution includes electrolyte salts and solvents.
  • the electrolyte is an electrolyte solution.
  • the electrolyte solution includes electrolyte salts and solvents.
  • the lithium salt may include lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium perchlorate (LiClO 4 ), lithium hexafluoroarsenate (LiAsF 6 ), lithium bisfluorosulfonimide (LiFSI), lithium bistrifluoromethanesulfonyl imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluoromethanesulfonate borate (LiDFOB), lithium dioxalatoborate (LiBOB), lithium difluorophosphate (LiPO 2 F 2 ), lithium difluorodioxalate phosphate (LiDFOP) and lithium tetrafluorooxalate phosphate (LiTFOP).
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium tetrafluoroborate
  • the organic solvent may include ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dimethyl carbonate, Propyl ester (DPC), methylpropyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), Propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4 - One or a combination of butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS) and diethyl sulfone (ESE).
  • EC
  • the electrolyte optionally further includes additives.
  • additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain properties of the battery, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.
  • the inventor found that when a specific additive, such as a first additive, is added to the electrolyte, the film-forming performance can be significantly improved, thereby improving the cycle performance of the secondary battery.
  • the properties of the first additive are as follows: the first additive is configured to form a film on the surface of the cathode active material, wherein the first additive includes an oxygen-containing heterocyclic compound having at least one heterocyclic element among sulfur, phosphorus, and boron. , and the oxygen-containing heterocyclic compound includes a mirror image structure symmetrical with a carbon-carbon single bond.
  • the first additive is a specific molecule with a symmetrical structure.
  • these molecules can first be oxidized to form a film on the surface of the positive active material prior to the solvent of the electrolyte. Secondly, these molecules will also be physically adsorbed on the surface of the positive active material. Due to their structure, Symmetry, good uniformity and consistency of its adsorption film formation, can improve problems such as gas production during high-temperature storage of positive electrode active materials, and further improve cycle characteristics. Moreover, since the surface of the positive active material is a coating layer, the coating layer is conducive to the adsorption of the first additive, further improving the film-forming effect of the first additive.
  • the first additive can also form a film on the surface of the negative active material, The film-forming performance on the surface of the negative electrode active material can also be improved, thereby further improving the cycle characteristics of the secondary battery.
  • the first additive includes sulfur; specifically, the first additive includes one or more compounds represented by formulas (2) to (5):
  • the above-mentioned additives are specific molecules containing sulfur atoms and having a symmetrical structure. These molecules can be oxidized to form films on the material surface in preference to solvents. Secondly, these molecules will also be physically adsorbed on the surface of the cathode active material. Due to the symmetry of their structure, they The adsorption film formation has good uniformity and consistency, which can improve the gas production problem of high-temperature storage of positive electrode active materials and further improve cycle characteristics.
  • the first additive includes at least two of the compounds represented by formula (2) to formula (5); based on the total molar amount of the first additive, the The ratio of the molar content of one compound to the molar content of the other compound is recorded as C, 1 ⁇ C ⁇ 2; optionally, 1.2 ⁇ C ⁇ 1.5.
  • the CEI film formed by the first additive on the surface of the positive electrode active material can be richer in components, the structure of the CEI film is more stable, and it is conducive to the insertion or extraction of active ions, thus improving the Cycling performance of secondary batteries.
  • the first additive may also be able to form a component-rich SEI film on the surface of the negative electrode active material, thereby further improving the cycle performance of the secondary battery.
  • the specific structural formulas of the above-mentioned phosphorus-containing additives are similar to formulas (2) to (5). The difference is that the sulfur element in formulas (2) to (5) is replaced by phosphorus. Element, specifically, its structural formula can be shown as formula (6):
  • the specific structural formulas of the above-mentioned boron-containing additives are similar to formulas (2) to (5). The difference is that the sulfur element in formulas (2) to (5) is replaced by boron. Element, specifically, its structural formula can be shown as formula (7):
  • the mass content of the first additive in the electrolyte is recorded as B%, where the secondary battery satisfies: 0.5 ⁇ B/A ⁇ 2.
  • the first additive in the electrolyte and the organic components in the cathode active material cooperate with each other to help form a uniform and dense CEI film on the surface of the cathode active material, which plays an excellent protective role for the active components in the cathode active material.
  • the mass content of the first additive in the electrolyte is recorded as B%, 0.10 ⁇ B ⁇ 0.70.
  • the secondary battery further includes a separator film.
  • a separator film There is no particular restriction on the type of isolation membrane in this application. Any well-known porous structure isolation membrane with good chemical stability and mechanical stability can be used.
  • the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the isolation film can be a single-layer film or a multi-layer composite film, with no special restrictions. When the isolation film is a multi-layer composite film, the materials of each layer can be the same or different, and there is no particular limitation.
  • the positive electrode piece, the negative electrode piece and the separator film can be made into an electrode assembly through a winding process or a lamination process.
  • This application has no particular limitation on the shape of the secondary battery, which can be cylindrical, square or any other shape. As shown in FIG. 1 , a square-structured secondary battery 5 is shown as an example.
  • the outer package may include a housing 51 and a cover 53 .
  • the housing 51 may include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose a receiving cavity.
  • the housing 51 has an opening communicating with the accommodation cavity, and the cover plate 53 is used to cover the opening to close the accommodation cavity.
  • the positive electrode piece, the negative electrode piece and the isolation film can be formed into the electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the containing cavity.
  • the electrolyte soaks into the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and can be adjusted according to needs.
  • the positive electrode sheet, the separator, the negative electrode sheet, and the electrolyte may be assembled to form a secondary battery.
  • the positive electrode sheet, isolation film, and negative electrode sheet can be formed into an electrode assembly through a winding process or a lamination process.
  • the electrode assembly is placed in an outer package, dried, and then injected with electrolyte. After vacuum packaging, standing, and Through processes such as formation and shaping, secondary batteries are obtained.
  • the secondary batteries according to the present application can be assembled into a battery module.
  • the number of secondary batteries contained in the battery module can be multiple, and the specific number can be adjusted according to the application and capacity of the battery module.
  • FIG. 3 is a schematic diagram of the battery module 4 as an example.
  • a plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4 .
  • the plurality of secondary batteries 5 can be fixed by fasteners.
  • the battery module 4 may further include a housing having a receiving space in which a plurality of secondary batteries 5 are received.
  • the above-mentioned battery modules can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 arranged in the battery box.
  • the battery box includes an upper box 2 and a lower box 3 .
  • the upper box 2 is used to cover the lower box 3 and form a closed space for accommodating the battery module 4 .
  • Multiple battery modules 4 can be arranged in the battery box in any manner.
  • the present application provides an electrical device.
  • the electrical device includes at least one of a secondary battery, a battery module and a battery pack of the present application.
  • Secondary batteries, battery modules and battery packs can be used as power sources for power-consuming devices, and can also be used as energy storage units for power-consuming devices.
  • Electric devices can be, but are not limited to, mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, and electric golf balls). vehicles, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • the electrical device can select secondary batteries, battery modules or battery packs according to its usage requirements.
  • FIG. 6 is a schematic diagram of an electrical device as an example.
  • the electric device 6 is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or the like.
  • a battery pack 1 or a battery module can be used.
  • the power-consuming device may be a mobile phone, a tablet computer, a laptop computer, etc.
  • the electrical device is usually required to be light and thin, and secondary batteries can be used as power sources.
  • Example 1 of Table 1 Dissolve the organic components shown in Example 1 of Table 1 into the ethyl acetate solvent, prepare an organic solution with a concentration of 10%, and add the active component (LiNi 0.8 Co 0.1 Mn 0.1 O 2 ) to the above solution.
  • the active component LiNi 0.8 Co 0.1 Mn 0.1 O 2
  • Mix at a mass ratio of 1:10 stir and disperse for 4 hours in an environment of 40°C to 50°C, add a certain amount of FeCl 3 initiator to further initiate cross-linking coating of the organic components, continue stirring for 4 hours, filter to remove the solvent, and then at 80 Dry in a vacuum oven at °C for 8 hours to obtain the active component coated with organic components, that is, the positive active material.
  • An aluminum foil with a thickness of 12 ⁇ m was used as the positive electrode current collector.
  • the positive electrode active material prepared in the above (1), the conductive agent Super P, and the binder polyvinylidene fluoride (PVDF) were mixed in N-methylpyrrolidone (NMP) to prepare a positive electrode slurry.
  • NMP N-methylpyrrolidone
  • the solid content in the positive electrode slurry is 50wt%, and the mass ratio of LiN i0.8 Co 0.1 Mn 0.1 O 2 , Super P, and PVDF in the solid content is 8:1:1.
  • the cathode slurry The material is coated on the current collector aluminum foil and dried at 85°C, then cold pressed, then trimmed, cut into pieces, and slit, and then dried under vacuum conditions at 85°C for 4 hours to make the positive electrode piece.
  • a copper foil with a thickness of 8 ⁇ m was used as the negative electrode current collector.
  • the non-aqueous organic solvents ethylene carbonate EC and diethyl carbonate DMC are mixed at a volume ratio of 1:1 to obtain an electrolyte solvent, and then the lithium salt and the mixed solvent are mixed to form The electrolyte with a lithium salt concentration of 1mol/L.
  • PE polyethylene film
  • Examples 2 to 14 adopt a method similar to Example 1 to prepare lithium ion batteries. The difference from Example 1 is that the types and amounts of organic components and electrolyte additives are adjusted in Examples 2 to 14.
  • Examples 15 to 18 adopt a method similar to Example 10 to prepare lithium ion batteries. The difference from Example 10 is that Examples 15 to 18 adjust the porosity of the coating layer formed by the organic component.
  • Examples 19 to 20 adopt a method similar to Example 10 to prepare lithium ion batteries. The difference from Example 10 is that Examples 19 to 20 adjust the types of electrolyte additives to be multiple.
  • Examples 21 to 23 adopt a method similar to Example 10 to prepare lithium ion batteries. The difference from Example 10 is that the organic components in Examples 21 to 23 are adjusted to small molecule monomer compounds.
  • Comparative Example 1 adopts a method similar to Example 1 to prepare a lithium-ion battery. The difference from Example 1 is that the organic component and the first additive are not provided in Comparative Example 1.
  • Example 2 The parameters of Example 2 to Example 23 and Comparative Example 1 are shown in Table 1:
  • Example 1 25°C, capacity retention rate/% after 600 cycles Volume growth rate after 30 days storage at 60°C/% DCR/m ⁇ Comparative example 1 77.2 15.9 20.3 Example 1 92.3 10.9 18.8 Example 2 91.3 12.1 19.1 Example 3 90.8 11.9 19.4 Example 4 91.2 11.3 19.9 Example 5 90.4 14.1 19.3 Example 6 91.8 10.6 20.1 Example 7 88.8 13.8 20.1 Example 8 89.2 10.1 20.8 Example 92.5 10.5 18.9 Example 10 94.7 9.9 20.1 Example 11 94.5 9.5 21.4 Example 12 92.4 10.8 18.9 Example 13 94.6 9.4 twenty three Example 14 94.5 10.3 20.8 Example 15 96.1 9.9 19.3 Example 16 96.3 10.2 19.4 Example 17 96.1 10.5 19.1 Example 18 96.0 10.4 19.5 Example 19 96.3 10.1 19.7 Example 20 96.5 10.0 19.6 Example 21 93.4 10.0 18.3 Example 22 92.7 9.6 18.7 Example 23 92.8 9.8 18.4
  • the active component is not coated, the structural stability of the active component is poor, and the cycle performance of the secondary battery is relatively poor.
  • the surface of the active component is coated with an organic component, which can protect the active component and improve the power characteristics (lower DC impedance) and cycle characteristics of the secondary battery.
  • the organic components are in cross-linked polymerization state (Example 1 to Example 20) and monomer state (Example 21 to Example 23), which can play a protective role in the active components.
  • the added content of the organic component is within a specific range of 0.1 ⁇ A ⁇ 0.5; especially 0.2 ⁇ A ⁇ 0.4, which can further improve the cycle characteristics and power characteristics of the secondary battery.
  • Examples 9 to 20 by containing an additive with a symmetrical molecular structure in the electrolyte, gas production at high temperatures can be suppressed and the cycle characteristics of the secondary battery can be improved.
  • the lithium-ion battery At 45°C, first charge the lithium-ion battery to 4.2V with a constant current of 1C, further charge it with a constant voltage of 4.2V to a current of 0.05C, and then discharge the lithium-ion battery to 2.8V with a constant current of 1C, as a During the charge and discharge cycle, the discharge capacity this time is the discharge capacity of the lithium-ion battery after the first cycle.
  • the lithium-ion battery was subjected to 600 cycle charge/discharge tests according to the above method.
  • Capacity retention rate (%) of a lithium-ion battery after 600 cycles discharge capacity after 600 cycles/discharge capacity after the first cycle ⁇ 100%.

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Abstract

La présente demande concerne un matériau actif d'électrode positive, une batterie secondaire et un dispositif électrique. Le matériau actif d'électrode positive comprend : un composant actif ; et une couche de revêtement comprenant un composant organique, la couche de revêtement recouvrant au moins une partie de la surface du composant actif, le composant organique comprenant un composé représenté par la formule (1) et/ou un polymère formé par polymérisation réticulée du composé représenté par la formule (1), dans laquelle M est choisi parmi un atome de phosphore, un atome de bore, ou un atome de soufre ; R est choisi parmi un ou plusieurs atomes d'oxygène, un groupe alcoxy en C1-C20, un groupe phénol aromatique en C6-C25 substitué ou non substitué, et un groupe phénol hétéroaromatique en C5-C25 substitué ou non substitué ; n représente le nombre de groupes R, et n est choisi parmi 2 ou 3. La présente demande peut permettre de réduire l'impédance et d'augmenter la puissance d'un matériau actif d'électrode positive.
PCT/CN2023/073929 2022-03-10 2023-01-31 Matériau actif d'électrode positive, batterie secondaire, module de batterie, bloc-batterie et dispositif électrique WO2023169096A1 (fr)

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