WO2024086978A1 - Matériau actif d'électrode positive et son procédé de préparation, feuille d'électrode positive, batterie secondaire et dispositif électronique - Google Patents

Matériau actif d'électrode positive et son procédé de préparation, feuille d'électrode positive, batterie secondaire et dispositif électronique Download PDF

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WO2024086978A1
WO2024086978A1 PCT/CN2022/127059 CN2022127059W WO2024086978A1 WO 2024086978 A1 WO2024086978 A1 WO 2024086978A1 CN 2022127059 W CN2022127059 W CN 2022127059W WO 2024086978 A1 WO2024086978 A1 WO 2024086978A1
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positive electrode
active material
electrode active
optionally
sintered product
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PCT/CN2022/127059
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English (en)
Chinese (zh)
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桓书星
沈重亨
罗东升
王帮润
陈强
吴奇
柳娜
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宁德时代新能源科技股份有限公司
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Priority to PCT/CN2022/127059 priority Critical patent/WO2024086978A1/fr
Publication of WO2024086978A1 publication Critical patent/WO2024086978A1/fr

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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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—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
    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • H01M4/78—Shapes other than plane or cylindrical, e.g. helical

Definitions

  • the present application relates to the technical field of secondary batteries, and in particular to a positive electrode active material and a preparation method thereof, a positive electrode sheet including the positive electrode active material, a secondary battery and an electrical device.
  • Secondary batteries are widely used in various consumer electronic products and electric vehicles due to their outstanding features of light weight, no pollution and no memory effect.
  • positive electrode materials are an important component of lithium-ion batteries.
  • common positive electrode materials include layered structure materials (such as lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, etc.), spinel structure materials, polyanion materials and ternary materials. High nickel ternary materials have received more and more attention due to their high energy density, low cost and reliable safety.
  • the present application is made in view of the above-mentioned problems, and its purpose is to provide a positive electrode active material, aiming to make the secondary battery containing the positive electrode active material have improved electrode sheet compaction density, energy density and cycle performance.
  • the first aspect of the present application provides a positive electrode active material, wherein the specific surface area (BET) of the positive electrode active material is ⁇ m 2 /g, the particle size Dv50 is ⁇ m, the 4T powder compaction density (CPD(4T)) is ⁇ g/cm 3 , and they satisfy the following relationship:
  • a pole sheet compaction density of at least 3.7 g/cm 3 can be achieved, so that a secondary battery prepared from the positive electrode active material has a higher energy density and improved cycle performance.
  • the positive electrode material has the following general formula:
  • the positive electrode active material When the positive electrode active material satisfies the relationship defined in this application, it can broaden the lithium ion channel and stabilize the material structure, so that the positive electrode material has a higher discharge capacity and a greatly improved cycle life. It can also effectively prevent the dissolution of transition metals and improve storage and safety performance.
  • the positive electrode active material includes a first positive electrode active material and a second positive electrode active material, wherein the first positive electrode active material is a polycrystalline material having the following general formula:
  • M is selected from one or more of Zr, Sr, Y, Sb, W, Ti, Mg, Nb, Hf, Mo, La, Na, B, Al, F and Ce;
  • the second positive electrode active material is a single crystal-like material having the following general formula:
  • M is selected from one or more of Zr, Sr, Y, Sb, W, Ti, Mg, Nb, Hf, Mo, La, Na, B, Al, F and Ce.
  • the particle size Dv50 of the positive electrode active material is ⁇ ⁇ m, wherein ⁇ is 4.0 to 15, and optionally 4.5 to 10.
  • the Dv50 of the first positive electrode active material is 6 ⁇ m to 20 ⁇ m, and optionally 7 ⁇ m to 18 ⁇ m.
  • the Dv50 of the second positive electrode active material is 2 ⁇ m to 6 ⁇ m, and optionally 2.5 ⁇ m to 4.0 ⁇ m.
  • the cycle performance can be better ensured, and the structural and kinetic properties of the material can be ensured.
  • the specific surface area (BET) of the positive electrode active material is ⁇ m 2 /g, wherein ⁇ is 0.34 to 0.8, and optionally 0.45 to 0.7.
  • the specific surface area (BET) of the first cathode active material is 0.2 m 2 /g to 0.8 m 2 /g; and/or the specific surface area (BET) of the second cathode active material is 0.6 m 2 /g to 1.3 m 2 /g.
  • the corrosion of the positive electrode active materials by the electrolyte can be delayed, the kinetic performance thereof can be ensured, and the materials can be easily processed.
  • the 4T powder compaction density (CPD(4T)) of the positive electrode active material is ⁇ g/cm 3 , wherein ⁇ is 3.2 to 4.2, and optionally 3.3 to 4.0.
  • the 4T powder compaction density (CPD(4T)) of the first cathode active material is 3.1 g/cm 3 to 3.7 g/cm 3 ; and/or the 4T powder compaction density (CPD(4T)) of the second cathode active material is 3.1 g/cm 3 to 3.7 g/cm 3 .
  • the pole sheet compaction density required by the present application can be ensured.
  • the SPAN value of the positive electrode active material is 1.4 to 2.7, and optionally 1.5 to 2.5.
  • the SPAN value of the first cathode active material is 0.9 to 1.5; and/or the SPAN value of the second cathode active material is 1.0 to 1.7.
  • the positive electrode active material has high dispersibility, thereby preparing a high compaction density positive electrode sheet.
  • high dispersibility can ensure that the single crystal-like small particles have good gap filling ability, making the materials more closely combined, thereby preparing a high compaction density positive electrode sheet.
  • the mass ratio of the first positive electrode active material to the second positive electrode active material is (9-1):1, and can be optionally (6-1.5):1.
  • the compaction density of the electrode sheet can be improved, while at the same time being able to utilize the advantages of the high capacity of the first positive electrode active material and the high cycle life of the second positive electrode active material to achieve optimization of capacity and electrical performance.
  • the second aspect of the present application also provides a method for preparing the positive electrode active material described in the first aspect of the present application, which comprises the following steps:
  • the lithium source and the precursor of the positive electrode active material are mixed uniformly and sintered in an oxygen atmosphere to obtain a first sintered product; the sintered product is crushed, screened and graded to obtain the positive electrode active material; optionally, the first sintered product is crushed and then washed in an aqueous solution containing a lithium source or in deionized water.
  • the first sintered product is uniformly mixed with another compound containing an element M and sintered for a second time in an oxygen atmosphere to obtain a second sintered product; the second sintered product is crushed, screened and graded to obtain a positive electrode active material; wherein M is selected from one or more of Zr, Sr, Y, Sb, W, Ti, Mg, Nb, Hf, Mo, La, Na, B, Al, F and Ce;
  • the sintering temperature is 550-900° C.; and the sintering time is 5-20 h.
  • S1 uniformly mixing a lithium source, a precursor of a first positive electrode active material and a compound containing element M and performing a first sintering in an oxygen atmosphere to obtain a first sintered product; crushing the first sintered product, uniformly mixing it with another compound containing element M and performing a second sintering in an oxygen atmosphere to obtain a second sintered product; crushing, screening and grading the second sintered product to obtain a first positive electrode active material; optionally, the sintering temperature is 550° C. to 800° C.; the sintering time is 5 h to 20 h;
  • S2 uniformly mixing a lithium source, a precursor of a second positive electrode active material and a compound containing element M and performing a first sintering in an oxygen atmosphere to obtain a first sintered product; crushing the first sintered product, uniformly mixing it with another compound containing element M and performing a second sintering in an oxygen atmosphere to obtain a second sintered product; crushing, screening and grading the second sintered product to obtain a second positive electrode active material; optionally, the sintering temperature is 600° C. to 900° C.; the sintering time is 5 h to 20 h;
  • the lithium source is selected from at least one of lithium carbonate, lithium hydroxide and lithium oxalate.
  • the precursor of the first cathode active material and the precursor of the second cathode active material are each at least one of Ni1 -x- yCoxMny (OH) 2 and Ni1 -xyCoxMnyCO3 , wherein 0.01 ⁇ x ⁇ 0.1 , 0.01 ⁇ y ⁇ 0.1 .
  • the element M is selected from one or more of Zr, Sr, Y, Sb, W, Ti, Mg, Nb, Hf, Mo, La, Na, B, Al, F and Ce.
  • the concentration of oxygen in the oxygen atmosphere is 80% or more, optionally 90% or more, and further optionally 99.9% or more.
  • a positive electrode active material with a high electrode compaction density can be obtained.
  • doping and coating with transition metal elements not only the structural stability of the material can be improved, but also the capacity, cycle life and storage performance of the positive electrode active material can be improved.
  • the third aspect of the present application provides a positive electrode plate, which includes a positive electrode collector and a positive electrode film layer arranged on at least one surface of the positive electrode collector, the positive electrode film layer includes the positive electrode active material described in the first aspect of the present application or the positive electrode active material prepared by the method described in the second aspect of the present application, and the content of the positive electrode active material in the positive electrode film layer is more than 10% by weight, based on the total weight of the positive electrode film layer.
  • the fourth aspect of the present application provides a secondary battery, which includes the positive electrode active material of the first aspect of the present application or the positive electrode active material prepared by the method of the second aspect of the present application or the positive electrode plate of the third aspect of the present application.
  • a fifth aspect of the present application provides an electrical device, comprising the secondary battery of the fourth aspect of the present application.
  • the electric device of the present application includes the secondary battery provided by the present application, it has at least the same advantages as the secondary battery.
  • FIG. 1 is a scanning electron microscope image of a cross section of a positive electrode sheet prepared from the positive electrode active material of Example 1 of the present application.
  • FIG. 2 is a normal temperature cycle diagram of a secondary battery prepared from the positive electrode active materials of Example 1 (2a) and Comparative Example 1 (2b) and Comparative Example 2 (2c) of the present application.
  • FIG. 3 is a schematic diagram of a battery cell according to an embodiment of the present application.
  • FIG. 4 is an exploded view of the battery cell according to the embodiment of the present application shown in FIG. 3 .
  • FIG. 5 is a schematic diagram of a battery module according to an embodiment of the present application.
  • FIG. 6 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 7 is an exploded view of the battery pack shown in FIG. 6 according to an embodiment of the present application.
  • FIG. 8 is a schematic diagram of an electric device using a secondary battery as a power source according to an embodiment of the present application.
  • “Scope” disclosed in the present application is defined in the form of lower limit and upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range.
  • the scope defined in this way can be including end values or excluding end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected.
  • the numerical range "a-b" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers.
  • the numerical range "0-5" represents that all real numbers between "0-5" have been fully listed herein, and "0-5" is just the abbreviation of these numerical combinations.
  • a parameter is expressed as an integer ⁇ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
  • 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.
  • the method may further include step (c), which means that step (c) may be added to the method in any order.
  • the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.
  • the “include” and “comprising” mentioned in this application represent open-ended or closed-ended expressions.
  • the “include” and “comprising” may represent that other components not listed may also be included or only the listed components may be included or only the listed components may be included.
  • the term "or” is inclusive.
  • the phrase “A or B” means “A, B, or both A and B”. More specifically, any of the following conditions satisfies the condition "A or B”: 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).
  • the compaction density of the positive electrode plate is usually increased.
  • the greater the compaction density of the plate the greater the degree of compression between the material particles, which makes the plate's absorption performance of the electrolyte worse, and the electrolyte is difficult to infiltrate the active material, resulting in a decrease in the battery's cycle performance.
  • the compaction density of the positive electrode plate can usually reach up to 3.5g/ cm3 . Generally, it becomes very difficult to further increase the compaction density of the plate and maintain the battery's cycle performance.
  • the compaction density of the pole piece is positively correlated with the compaction density of the powder to a large extent, and many research patents have also confirmed this point (see, for example, CN113921782A), but the factor affecting the compaction density of the pole piece is not only the compaction density of the powder.
  • the median particle size Dv50 of the positive electrode material can also affect the compaction density of the pole piece and its cycle life.
  • the particle size distribution of the positive electrode material will shift to the left as a whole, and there will be more small particles, and the material filling capacity will become stronger, but Dv50 cannot be too small, otherwise it will cause too much micropowder to affect the processing performance. Therefore, there are many factors that affect the compaction density of the pole piece.
  • the inventors unexpectedly discovered that when the compaction density, median particle size and specific surface area of the positive electrode active material meet the conditions specified in the present application, a pole piece compaction density of at least 3.7 g/ cm3 can be achieved, and the electrical performance of the prepared battery can also be improved.
  • the first aspect of the present application provides a positive electrode active material, wherein the specific surface area (BET) of the positive electrode active material is ⁇ m 2 /g, the particle size Dv50 is ⁇ m, and the 4T powder compaction density (CPD(4T)) is ⁇ g/cm 3 , and they satisfy the following relationship:
  • a pole sheet compaction density of at least 3.7 g/cm 3 can be achieved, and a secondary battery prepared from the positive electrode active material has a higher energy density and improved cycle performance.
  • the cathode material has the following general formula:
  • the positive electrode active material When the positive electrode active material satisfies the relationship defined in this application, it can broaden the lithium ion channel and stabilize the material structure, so that the positive electrode material has a higher discharge capacity and a greatly improved cycle life. At the same time, it can also effectively prevent the dissolution of transition metals and improve storage and safety performance.
  • the positive electrode active material includes a first positive electrode active material and a second positive electrode active material, wherein the first positive electrode active material is a polycrystalline material having the following general formula:
  • M is selected from one or more of Zr, Sr, Y, Sb, W, Ti, Mg, Nb, Hf, Mo, La, Na, B, Al, F and Ce;
  • the second positive electrode active material is a single crystal-like material having the following general formula:
  • M is selected from one or more of Zr, Sr, Y, Sb, W, Ti, Mg, Nb, Hf, Mo, La, Na, B, Al, F and Ce.
  • the polycrystal refers to a secondary particle, which is a state in which a plurality of primary particles are aggregated together to form a spherical particle;
  • the quasi-single crystal refers to a primary particle, which is larger than 0.9 ⁇ m in size, and is a single particle or a state in which several primary particles are adhered but without obvious agglomeration.
  • the above-mentioned limitation on the numerical range of z1 is not only a limitation on the stoichiometric number of each element as M, but also a limitation on the sum of the stoichiometric numbers of each element as M. That is, when M is more than two elements M1, M2...Mn, the stoichiometric numbers z11, z12...z1n of M1, M2...Mn must each fall within the numerical range of z1 defined in the present application, and the sum of z11, z12...z1n must also fall within the numerical range.
  • first positive electrode active material polycrystalline material and polycrystalline agglomerates
  • second positive electrode active material single crystal material and single crystal-like small particles
  • the particle size Dv50 of the positive electrode active material is ⁇ ⁇ m, wherein ⁇ is 4.0 to 15, optionally 4.5 to 10, and further optionally 4.7 to 9.
  • the Dv50 of the first positive electrode active material is 6 ⁇ m to 20 ⁇ m, optionally 7 ⁇ m to 18 ⁇ m, and further optionally 8.5 ⁇ m to 17.8 ⁇ m.
  • the Dv50 of the second positive active material is 2 ⁇ m to 6 ⁇ m, optionally 2.5 ⁇ m to 4.0 ⁇ m, and further optionally 2.6 ⁇ m to 3.9 ⁇ m.
  • the cycle performance can be better ensured, and the structural and kinetic properties of the material can be ensured.
  • the specific surface area (BET) of the positive electrode active material is ⁇ m 2 /g, wherein ⁇ is 0.34 to 0.8, optionally 0.45 to 0.7, and further optionally 0.46 to 0.68.
  • the specific surface area (BET) of the first cathode active material is 0.2m2 /g to 0.8m2 /g, optionally 0.25m2 /g to 0.6m2 /g; and/or the specific surface area (BET) of the second cathode active material is 0.6m2 /g to 1.3m2 /g, optionally 0.7m2 /g to 1.2m2 /g.
  • the corrosion of the positive electrode active materials by the electrolyte can be delayed, the kinetic performance thereof can be ensured, and the materials can be easily processed.
  • the specific surface area test refers to GB/T 19587-2017, and the nitrogen adsorption specific surface area analysis test method is used for testing using the Tri-Star 3020 specific surface area pore size analyzer of Micromeritics, USA.
  • the specific surface area of the material is calculated using the BET (Brunauer Emmett Teller) method.
  • the 4T powder compaction density (CPD(4T)) of the positive electrode active material is ⁇ g/cm 3 , wherein ⁇ is 3.2 to 4.2, and optionally 3.3 to 4.0.
  • the 4T powder compaction density (CPD(4T)) of the first cathode active material is 3.1 g/cm 3 to 3.7 g/cm 3 , optionally 3.2 g/cm 3 to 3.6 g/cm 3 ; and/or the 4T powder compaction density (CPD(4T)) of the second cathode active material is 3.1 g/cm 3 to 3.7 g/cm 3 , optionally 3.2 g/cm 3 to 3.5 g/cm 3 .
  • the pole piece compaction density required by the present application can be ensured.
  • the powder compaction density can reflect the pole piece compaction density to a certain extent. When BET, particle size, etc. remain unchanged, the higher the powder compaction density, the greater the pole piece compaction density.
  • the powder compaction density can be measured according to GB/T 24533-2009.
  • the SPAN value of the positive electrode active material is 1.4 to 2.7, optionally 1.5 to 2.5, further optionally 1.8 to 2.4, further optionally 1.9 to 2.25, further optionally 2.05 to 2.24.
  • the SPAN value (Dv90-Dv10)/Dv50.
  • the SPAN value of the first cathode active material is 0.9 to 1.5, optionally 1.0 to 1.4, and optionally 1.2 to 1.4; and/or the SPAN value of the second cathode active material is 1.0 to 1.7, and optionally 1.3 to 1.65.
  • the positive electrode active material has high dispersibility, thereby preparing a high compaction density positive electrode sheet.
  • high dispersibility can ensure that the single crystal-like small particles have good gap filling ability, making the materials more closely combined, thereby preparing a high compaction density positive electrode sheet.
  • the mass ratio of the first positive electrode active material to the second positive electrode active material is (9-1):1, optionally (6-1.5):1, further optionally (5.8-2):1, further optionally (5.5-2.2):1, and further optionally (4-2.5):1.
  • the mass ratio of the first positive electrode active material to the second positive electrode active material is (90-40):(60-10), optionally (85-50):(50-25), and further optionally (80-60):(40-20), and the sum of the masses of the first positive electrode active material and the second positive electrode active material is calculated as 100 parts.
  • the compaction density of the electrode sheet can be improved, while taking advantage of the high capacity of the first positive electrode active material and the high cycle life of the second positive electrode active material to achieve optimization of capacity and electrical performance.
  • the second aspect of the present application also provides a method for preparing the positive electrode active material described in the first aspect of the present application, which comprises the following steps:
  • the lithium source and the precursor of the positive electrode active material are mixed uniformly and sintered in an oxygen atmosphere to obtain a first sintered product; the sintered product is crushed, screened and graded to obtain the positive electrode active material; optionally, the first sintered product is crushed and then washed in an aqueous solution containing a lithium source or in deionized water.
  • the first sintered product is uniformly mixed with another compound containing an element M and sintered for a second time in an oxygen atmosphere to obtain a second sintered product; the second sintered product is crushed, screened and graded to obtain a positive electrode active material; wherein M is selected from one or more of Zr, Sr, Y, Sb, W, Ti, Mg, Nb, Hf, Mo, La, Na, B, Al, F and Ce;
  • the sintering temperature is 550-900° C.; and the sintering time is 5-20 h.
  • it comprises the following steps:
  • S1 uniformly mixing a lithium source, a precursor of a first positive electrode active material and a compound containing element M and performing a first sintering in an oxygen atmosphere to obtain a first sintered product; crushing the first sintered product, uniformly mixing it with another compound containing element M and performing a second sintering in an oxygen atmosphere to obtain a second sintered product; crushing, screening and grading the second sintered product to obtain a first positive electrode active material; optionally, the sintering temperature is 550° C. to 800° C.; the sintering time is 5 h to 20 h;
  • S2 uniformly mixing a lithium source, a precursor of a second positive electrode active material and a compound containing element M and performing a first sintering in an oxygen atmosphere to obtain a first sintered product; crushing the first sintered product, uniformly mixing it with another compound containing element M and performing a second sintering in an oxygen atmosphere to obtain a second sintered product; crushing, screening and grading the second sintered product to obtain a second positive electrode active material; optionally, the sintering temperature is 600°C to 900°C; the sintering time is 5h to 20h;
  • the lithium source is selected from at least one of lithium carbonate, lithium hydroxide and lithium oxalate.
  • the precursor of the first cathode active material and the precursor of the second cathode active material are each at least one of Ni1 -x- yCoxMny (OH) 2 and Ni1 -xyCoxMnyCO3 , wherein 0.01 ⁇ x ⁇ 0.1 , 0.01 ⁇ y ⁇ 0.1 .
  • the precursor of the first positive electrode active material and the precursor of the second positive electrode active material can be prepared by a method known in the prior art (e.g., by coprecipitation reaction). For example, by preparing an aqueous solution of nickel sulfate, cobalt sulfate and manganese sulfate, and then placing the solution in a reactor and adjusting the particle size and microscopic morphology by controlling the reaction time, reaction temperature, pH value and ammonia concentration, the first and second positive electrode active material precursors with different particle sizes can be prepared respectively.
  • the molar ratio of the lithium source to the precursor of the first positive electrode active material is (0.97-1.09):1, and can be optionally (1-1.05):1.
  • the added amount of the compound containing element M is generally 100 ppm to 9000 ppm, optionally 200 ppm to 7000 ppm, further optionally 500 ppm to 5000 ppm, and further optionally 800 ppm to 2000 ppm, based on the total mass of the lithium source and the precursor of the first positive electrode active material.
  • the addition amount of another compound containing element M is generally 100 ppm to 9000 ppm, optionally 200 ppm to 7000 ppm, further optionally 500 ppm to 5000 ppm, further optionally 800 ppm to 2000 ppm, based on the total mass of the lithium source and the precursor of the first positive electrode active material.
  • the sintering temperature of the first sintering is 550°C to 800°C, optionally 650°C to 750°C, and the sintering time is 5h to 20h, optionally 10h to 18h.
  • the sintering temperature of the second sintering is 400°C to 720°C, optionally 420°C to 500°C, and the sintering time is 5h to 20h, optionally 8h to 15h.
  • the element M is selected from one or more of Zr, Sr, Y, Sb, W, Ti, Mg, Nb, Hf, Mo, La, Na, B, Al, F and Ce.
  • the compound containing the element M is selected from one or more of a simple substance, an oxide, a boride, a phosphate, an oxalate, a carbonate and a sulfate of M.
  • steps S1 and S2 two compounds containing element M are used in each step, that is, the first compound containing element M is different from the other compound containing element M.
  • the concentration of oxygen in the oxygen atmosphere is greater than 80%, optionally greater than 90%, and further optionally greater than 99.9%.
  • step S2 the molar ratio of the lithium source to the precursor of the second positive electrode active material is (0.97-1.09):1, and can be optionally (1-1.05):1.
  • the added amount of the compound containing element M is generally 100 ppm to 9000 ppm, optionally 200 ppm to 7000 ppm, further optionally 300 ppm to 4000 ppm, and further optionally 400 ppm to 1000 ppm, based on the total mass of the lithium source and the precursor of the first positive electrode active material.
  • the addition amount of another compound containing element M is generally 100 ppm to 9000 ppm, optionally 200 ppm to 7000 ppm, further optionally 500 ppm to 5000 ppm, and further optionally 800 ppm to 2000 ppm, based on the total mass of the lithium source and the precursor of the first positive electrode active material.
  • the sintering temperature of the first sintering is 600°C to 900°C, and may be 700°C to 850°C, and the sintering time is 5h to 20h, and may be 10h to 18h.
  • the concentration of the lithium source in the lithium source aqueous solution is 2 g/L to 5 g/L, and can also be 3 g/L to 4 g/L; and/or, the lithium source is selected from at least one of lithium carbonate, lithium hydroxide and lithium oxalate.
  • the first sintered product is preferably crushed and washed in an aqueous solution containing a lithium source.
  • an aqueous solution containing a lithium source By using an aqueous solution containing a lithium source, the cycle performance of the prepared secondary battery can be better ensured, and the structural and dynamic properties of the material can be ensured.
  • the drying temperature is 80°C to 180°C, and may be 100°C to 150°C, and the drying time is 1 hour to 8 hours, and may be 3 hours to 4 hours.
  • the sintering temperature of the second sintering is 400°C to 820°C, optionally 420°C to 600°C, and the sintering time is 5h to 20h, and optionally 8h to 15h.
  • the mass ratio of the first positive electrode active material to the second positive electrode active material is (9-1):1, optionally (6-1.5):1, further optionally (5.8-2):1, further optionally (5.5-2.2):1, and further optionally (4-2.5):1.
  • the mixing time can be adjusted as needed, and can be selected to be 0.5 h to 2 h.
  • the third aspect of the present application provides a positive electrode plate, which includes a positive electrode collector and a positive electrode film layer arranged on at least one surface of the positive electrode collector, the positive electrode film layer includes the positive electrode active material described in the first aspect of the present application or the positive electrode active material prepared by the method described in the second aspect of the present application, and the content of the positive electrode active material in the positive electrode film layer is more than 10 weight%, based on the total weight of the positive electrode film layer.
  • the content of the positive electrode active material in the positive electrode film layer is 95-99.5% by weight, and optionally 96-99% by weight, based on the total weight of the positive electrode film layer.
  • the surface density of the positive electrode sheet is 17.5 mg/cm 2 to 22 mg/cm 2 , and can be 18.5 mg/cm 2 to 21 mg/cm 2 .
  • the surface density of the positive electrode film layer has a meaning well known in the art and can be tested by methods known in the art. For example, take a single-sided coated and cold-pressed positive electrode sheet (if it is a double-sided coated positive electrode sheet, the positive electrode active material layer on one side can be wiped off first), punch it into small discs with an area of S1, weigh it, and record it as M1. Then wipe off the positive electrode active material layer of the above-mentioned weighed positive electrode sheet, weigh the weight of the positive electrode collector, and record it as M0.
  • the surface density of the positive electrode active material layer (weight of the positive electrode sheet M1 - weight of the positive electrode collector M0) / S1.
  • multiple groups for example, 10 groups
  • the average value is calculated as the test result.
  • the compaction density of the positive electrode sheet is 3.7 g/cm 3 to 4 g/cm 3 , and can be 3.7 g/cm 3 to 3.85 g/cm 3 .
  • the elongation of the positive electrode sheet is 0.7% to 0.8%.
  • the fourth aspect of the present application provides a secondary battery, which includes the positive electrode active material of the first aspect of the present application or the positive electrode active material prepared by the method of the second aspect of the present application or the positive electrode plate of the third aspect of the present application.
  • a secondary battery includes a positive electrode sheet, a negative electrode sheet, an electrolyte and a separator.
  • active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet.
  • the electrolyte plays the role of conducting ions between the positive electrode sheet and the negative electrode sheet.
  • the separator is set between the positive electrode sheet and the negative electrode sheet, mainly to prevent the positive and negative electrodes from short-circuiting, while allowing ions to pass through.
  • the secondary battery of the present application is described below with reference to the accompanying drawings as appropriate.
  • the secondary battery may be in the form of a battery cell, a battery module, or a battery pack.
  • a battery cell is provided.
  • a battery cell includes a positive electrode sheet, a negative electrode sheet, an electrolyte and a separator.
  • active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet.
  • the electrolyte plays the role of conducting ions between the positive electrode sheet and the negative electrode sheet.
  • the separator is set between the positive electrode sheet and the negative electrode sheet, mainly to prevent the positive and negative electrodes from short-circuiting, while allowing ions to pass through.
  • the positive electrode plate includes a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, wherein the positive electrode film layer includes the positive electrode active material of the first aspect of the present application.
  • the positive electrode current collector has two surfaces opposite to 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 current collector may be a metal foil or a composite current collector.
  • aluminum foil may be used as the metal foil.
  • the composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base.
  • the composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene terephthalate
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the positive electrode active material may also be a positive electrode active material for a battery known in the art.
  • the positive electrode active material may include at least one of the following materials: a lithium-containing phosphate with an olivine structure, a lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more.
  • lithium transition metal oxides may include, but are not limited to , lithium cobalt oxide (such as LiCoO2 ), lithium nickel oxide (such as LiNiO2 ), lithium manganese oxide (such as LiMnO2 , LiMn2O4 ), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi1 / 3Co1 / 3Mn1 / 3O2 (also referred to as NCM333 ), LiNi0.5Co0.2Mn0.3O2 (also referred to as NCM523 ) , LiNi0.5Co0.25Mn0.25O2 (also referred to as NCM211 ) , LiNi0.6Co0.2Mn0.2O2 (also referred to as NCM622 ), LiNi0.8Co0.1Mn0.1O2 (also referred to as NCM811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05
  • lithium-containing phosphates with an olivine structure may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO 4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 (also referred to as LFP)
  • LiMnPO 4 lithium manganese phosphate
  • LiMnPO 4 lithium manganese phosphate
  • LiMnPO 4 lithium manganese phosphate and carbon
  • the positive electrode film layer may further optionally include a binder.
  • the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin.
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • PTFE polytetrafluoroethylene
  • vinylidene fluoride-tetrafluoroethylene-propylene terpolymer vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer
  • the binder accounts for 0.1% to 4% by mass of the positive electrode film layer, and optionally 0.5% to 2% by mass.
  • the positive electrode film layer may further include a conductive agent, which may include, for example, at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • a conductive agent which may include, for example, at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • the conductive agent accounts for 0.1% to 4% by mass of the positive electrode film layer, and can be optionally 0.5% to 2% by mass.
  • the positive electrode sheet can be prepared in the following manner: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.
  • a solvent such as N-methylpyrrolidone
  • 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, wherein the negative electrode film layer includes a negative electrode active material.
  • the negative electrode current collector has two surfaces opposite to each other in its 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 metal foil copper foil may be used.
  • 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 substrate.
  • the composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene terephthalate
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative electrode active material may be a negative electrode active material for a battery known in the art.
  • the negative electrode 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, etc.
  • 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 negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.
  • the mass percentage of the negative electrode active material in the negative electrode film layer is 75% to 99%, and optionally 80% to 98%.
  • the negative electrode film layer may further include a binder.
  • the binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the binder accounts for 0.1% to 3.5% by mass of the negative electrode film layer, and optionally 0.5% to 2.5% by mass.
  • the negative electrode film layer may further include a conductive agent, which may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • a conductive agent which 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 conductive agent accounts for 0.04% to 5% by mass of the negative electrode film layer, and can be optionally 0.5% to 3% by mass.
  • the negative electrode film layer may optionally include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).
  • a thickener eg, sodium carboxymethyl cellulose (CMC-Na)
  • the negative electrode sheet can be prepared in the following manner: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.
  • a solvent such as deionized water
  • the electrolyte plays the role of conducting ions between the positive electrode and the negative electrode.
  • the present application has no specific restrictions on the type of electrolyte, which can be selected according to needs.
  • the electrolyte can be liquid, gel or all-solid.
  • the electrolyte is an electrolyte solution, which includes an electrolyte salt and a solvent.
  • the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.
  • the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane sulfone, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • the concentration of the electrolyte salt in the non-aqueous electrolyte is, for example, 0.3 mol/L (mole/liter) or more, optionally 0.7 mol/L or more, optionally 1.7 mol/L or less, and further optionally 1.2 mol/L or less.
  • the electrolyte may further include additives, such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.
  • additives such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.
  • the battery cell further includes a separator.
  • the present application has no particular limitation on the type of separator, and any known porous separator with good chemical stability and mechanical stability can be selected.
  • 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 membrane can be a single-layer film or a multi-layer composite film, without particular limitation.
  • the materials of each layer can be the same or different, without particular limitation.
  • the positive electrode sheet, the negative electrode sheet, and the separator may be formed into an electrode assembly by a winding process or a lamination process.
  • the battery cell may include an outer packaging, which may be used to encapsulate the electrode assembly and the electrolyte.
  • the outer packaging of the battery cell may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.
  • the outer packaging of the secondary battery may also be a soft package, such as a bag-type soft package.
  • the material of the soft package may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.
  • FIG3 is a battery cell 5 of a square structure as an example.
  • the outer package may include a shell 51 and a cover plate 53.
  • the shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity.
  • the shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity.
  • the positive electrode sheet, the negative electrode sheet and the isolation film can form an electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is encapsulated in the receiving cavity.
  • the electrolyte is infiltrated in the electrode assembly 52.
  • the number of electrode assemblies 52 contained in the battery cell 5 can be one or more, and those skilled in the art can select according to specific actual needs.
  • battery cells may be assembled into a battery module.
  • the number of battery cells contained in the battery module may be one or more, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery module.
  • FIG5 is a battery module 4 as an example.
  • a plurality of battery cells 5 may be arranged in sequence along the length direction of the battery module 4. Of course, they may also be arranged in any other manner. Further, the plurality of battery cells 5 may be fixed by fasteners.
  • the battery module 4 may further include a housing having a receiving space, and the plurality of battery cells 5 are received in the receiving space.
  • the battery cells can be assembled into a battery pack.
  • the battery modules can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery pack.
  • FIG6 and FIG7 are battery packs 1 as an example.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box.
  • the battery box includes an upper box body 2 and a lower box body 3, and the upper box body 2 can be covered on the lower box body 3 to form a closed space for accommodating the battery modules 4.
  • the plurality of battery modules 4 can be arranged in the battery box in any manner.
  • the present application also provides an electric device, the electric device includes the secondary battery provided in the present application.
  • the secondary battery can be used as a power source for the electric device, and can also be used as an energy storage unit for the electric device.
  • the electric device may include 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, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited thereto.
  • a secondary battery can be selected according to its usage requirements.
  • FIG8 is an example of an electric device.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.
  • a battery pack or a battery module may be used.
  • a device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is usually required to be light and thin, and a battery cell may be used as a power source.
  • the polycrystalline agglomerates P and the single-crystal-like small particles S are uniformly mixed in a mass ratio of 75:25 to obtain the positive electrode active material of the present application.
  • the positive electrode active material, conductive agent acetylene black (SP) and binder polyvinylidene fluoride (PVDF) were put into a 5L stirring tank at a mass ratio of 97:1.5:1.5 for premixing for 30 minutes, and finally N-methylpyrrolidone (NMP) was added as solvent and stirred rapidly under vacuum to form slurry with a solid content of 70% by weight.
  • NMP N-methylpyrrolidone
  • the slurry was evenly coated on both sides of an aluminum foil with a thickness of 12 ⁇ m.
  • the coated electrode was taken out after drying in an oven at 100°C for half an hour, with a surface density of 19.5mg/ cm2 and a compacted density of 3.70g/ cm3 .
  • the negative electrode active material artificial graphite, hard carbon, conductive agent acetylene black, binder styrene butadiene rubber (SBR), and thickener sodium carboxymethyl cellulose (CMC-Na) were mixed uniformly in deionized water at a weight ratio of 90:5:2:2:1, coated on copper foil, dried, and cold pressed to obtain a negative electrode sheet with a coating amount of 12.5 g/ cm2 .
  • Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1, and then LiPF6 is uniformly dissolved in the above solution to obtain an electrolyte, wherein the concentration of LiPF6 is 1 mol/L.
  • a polyethylene (PE) porous polymer film is used as the isolation membrane.
  • the positive electrode sheet, separator, and negative electrode sheet are stacked in order, so that the separator is between the positive and negative electrodes to play a role of isolation, and then wound to obtain a bare cell.
  • the bare cell is placed in an outer package, injected with electrolyte and packaged to obtain a full battery.
  • the length ⁇ width ⁇ height of the full battery 90mm ⁇ 30mm ⁇ 60mm, and the battery group margin is 97%.
  • the preparation method is basically the same as that of Example 1, but only some parameters are changed. For specific variables, see Tables 1 and 2.
  • the preparation method is similar to that of Example 1, except that only the first positive electrode active material is used and the parameters of the first positive electrode active material are different, see Table 2 for details.
  • the preparation method is similar to that of Example 1, except that the mixing ratio of the first positive electrode active material and the second positive electrode active material and their parameters are different, see Tables 1 and 2 for details.
  • the preparation method is similar to that of Example 1, except that only the first positive electrode active material is used and the parameters of the first positive electrode active material are different, see Table 2 for details.
  • the length after roller cold pressing is L1.
  • the specific surface area test was carried out according to GB/T 19587-2017, using the Tri-Star 3020 specific surface area pore size analyzer from Micromeritics, USA, to perform nitrogen adsorption specific surface area analysis test method, and the specific surface area of the material was calculated using the BET (Brunauer Emmett Teller) method.
  • BET Brunauer Emmett Teller
  • the particle size of the positive electrode active material is determined according to GB/T 19077.1-2016/ISO 13320:2009 (laser diffraction method for particle size distribution). Take a clean beaker, add an appropriate amount of the above-mentioned positive electrode active material, add an appropriate amount of pure water, and use ultrasound at 120W/5min to ensure that the material powder is completely dispersed in the water. After the solution is poured into the injection tower of the laser particle size analyzer (Malvern Company, model: Mastersizer3000), it circulates to the test optical path system with the solution.
  • the laser particle size analyzer Malvern Company, model: Mastersizer3000
  • the particles are irradiated by the laser beam, and the particle size distribution characteristics of the particles (shading degree: 8-12%) can be obtained by receiving and measuring the energy distribution of the scattered light, and the corresponding values of Dv10, Dv50, and Dv90 are read.
  • the test results are shown in Tables 1 and 2.
  • the compaction density of the positive electrode active material under 4T pressure (i.e., under 4 tons of pressure) is determined according to GB/T 24533-2009.
  • a certain amount of the powder of the positive electrode active material is placed in a special compaction mold, and then the mold is placed on the compaction density instrument.
  • the test results are shown in Tables 1 and 2.
  • the morphology of the cross section of the positive electrode sheet made of the positive electrode active material of Example 1 was characterized using a field emission scanning electron microscope (Sigma300) from ZEISS, Germany. The result is shown in FIG1 .
  • the secondary battery prepared by using the positive electrode active material of the present application not only has a better electrode compaction density and achieves a higher energy density, but also can achieve better cycle performance.

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Abstract

La présente demande concerne un matériau actif d'électrode positive. La surface spécifique (BET) du matériau actif d'électrode positive est α m2/g, la taille de particule Dv50 est β μm, la densité de compactage de poudre 4T (CPD(4T)) est ɣ g/cm3, et celles-ci satisfont l'expression relationnelle suivante : -α2+1,24α+0,136ɣ-0,0123β=K, et 0,75≤K≤0,85. À condition que le matériau actif d'électrode positive satisfait l'expression relationnelle définie dans la présente invention, la densité de compactage d'une feuille d'électrode d'au moins 3,7 g/cm3 peut être réalisée, et en outre, la batterie secondaire préparée à partir du matériau actif d'électrode positive présente une densité d'énergie supérieure et une performance de cycle améliorée. La présente demande concerne en outre une batterie secondaire comprenant le matériau actif d'électrode positive et un dispositif électrique.
PCT/CN2022/127059 2022-10-24 2022-10-24 Matériau actif d'électrode positive et son procédé de préparation, feuille d'électrode positive, batterie secondaire et dispositif électronique WO2024086978A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111384372A (zh) * 2018-12-29 2020-07-07 宁德时代新能源科技股份有限公司 一种高压实密度正极材料及电化学储能装置
CN112447968A (zh) * 2019-09-02 2021-03-05 宁德时代新能源科技股份有限公司 正极活性材料、正极极片及锂离子二次电池
CN112447964A (zh) * 2019-09-02 2021-03-05 宁德时代新能源科技股份有限公司 正极活性材料、正极极片及锂离子二次电池
CN115084508A (zh) * 2022-08-23 2022-09-20 欣旺达电动汽车电池有限公司 正极活性材料、电池及其制备方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111384372A (zh) * 2018-12-29 2020-07-07 宁德时代新能源科技股份有限公司 一种高压实密度正极材料及电化学储能装置
CN112447968A (zh) * 2019-09-02 2021-03-05 宁德时代新能源科技股份有限公司 正极活性材料、正极极片及锂离子二次电池
CN112447964A (zh) * 2019-09-02 2021-03-05 宁德时代新能源科技股份有限公司 正极活性材料、正极极片及锂离子二次电池
CN115084508A (zh) * 2022-08-23 2022-09-20 欣旺达电动汽车电池有限公司 正极活性材料、电池及其制备方法

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