WO2024036472A1 - Positive electrode active material and preparation method therefor, positive electrode plate, secondary battery, battery module, battery pack and electric device - Google Patents

Positive electrode active material and preparation method therefor, positive electrode plate, secondary battery, battery module, battery pack and electric device Download PDF

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WO2024036472A1
WO2024036472A1 PCT/CN2022/112738 CN2022112738W WO2024036472A1 WO 2024036472 A1 WO2024036472 A1 WO 2024036472A1 CN 2022112738 W CN2022112738 W CN 2022112738W WO 2024036472 A1 WO2024036472 A1 WO 2024036472A1
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active material
lithium
cathode active
positive electrode
optionally
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PCT/CN2022/112738
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French (fr)
Chinese (zh)
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魏冠杰
古力
孟阵
张宇
李星
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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/CN2022/112738 priority Critical patent/WO2024036472A1/en
Publication of WO2024036472A1 publication Critical patent/WO2024036472A1/en

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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
    • H01M4/50—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
    • 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 technical field of lithium batteries, and in particular to a positive active material and a preparation method thereof, as well as a positive electrode sheet, a secondary battery, a battery module, a battery pack and an electrical device including the positive active material.
  • lithium-ion batteries are widely used in energy storage power systems such as hydraulic, thermal, wind and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, Military equipment, aerospace and other fields. Due to the great development of lithium-ion batteries, higher requirements have been put forward for their energy density, cycle performance and safety performance.
  • cathode materials include layered structure materials (such as lithium cobalt oxide, lithium manganate, lithium nickel oxide, etc.), spinel structure materials, polyanionic materials, ternary materials, and lithium-rich materials that are currently attracting much attention. wait.
  • lithium-ion battery systems prepared from these cathode materials still have problems such as low energy density, high cost, and poor safety. They cannot meet people's growing needs for battery fast charging, cycle stability, safety, etc. Therefore, it is necessary to adopt Certain strategies are used to optimize cathode materials to improve secondary battery cycle performance, rate performance and safety performance.
  • This application was conducted in view of the above-mentioned issues, and its purpose is to provide a cathode active material with improved cycle performance and rate performance, and to provide a preparation method of the cathode active material and a cathode active material containing the cathode active material of the application.
  • a first aspect of the present application provides a cathode active material.
  • the cathode active material is a secondary particle formed by stacking primary particles, wherein the primary particles include a lithium-rich manganese-based matrix material and a
  • the coating layer on the surface of the lithium-rich manganese base material includes a fast ion conductor and a metal compound conductive agent.
  • the cathode active material of the present application has improved cycle performance and rate performance.
  • the fast ion conductor is selected from one or more of lithium silicate, lithium phosphate, lithium borate, lithium niobate, lithium aluminate, lithium zirconate and lithium pyrophosphate, optionally,
  • the fast ion conductor is selected from one or more of lithium silicate, lithium phosphate and lithium borate; optionally, the amount of the fast ion conductor is 0.5-20% by weight, optionally 2-12% by weight , based on the weight of the cathode active material.
  • the metal compound conductive agent is selected from one or more of titanium carbide, titanium nitride and titanium boride; optionally, the amount of the metal compound conductive agent is 0.5-10% by weight. , optionally 1-6% by weight, based on the weight of the cathode active material.
  • the weight ratio of the fast ion conductor to the metal compound conductive agent in the cathode active material is 1.3-3:1, optionally 1.7-2.7:1.
  • the chemical formula of the lithium-rich manganese-based matrix material is xLi 2 MnO 3 ⁇ (1-x)LiMO 2 , wherein M is selected from Fe, Al, Co, Mn, Ni, Cr, Ti , Mo, Nb, Zr, Sn, V, Mg, Cu, Zn, B, Na, Ca and Ru in one or more combinations, optionally, the M is selected from Co, Ni, Cr, One or a combination of one or more of V, Mo, Mn, Al, Nb and Ti, and 0 ⁇ x ⁇ 1.
  • the Dv50 of the positive active material is 5-20 ⁇ m, optionally 7-13 ⁇ m, and the Dv50 of the primary particles is 0.05-1 ⁇ m, optionally 0.1-0.4 ⁇ m.
  • the particle size of the positive active material is within the above range, the compacted density of the positive active material can be optimized, thereby further improving the performance of the positive active material.
  • the compacted density of the positive active material under 5 tons of force is 2.4-3.4g/cm 3 , optionally 2.7-3.2g/cm 3 .
  • the filling degree between the particles of the cathode active material is high, which is beneficial to further improving the processing performance of the cathode active material.
  • the thickness of the coating layer is 0.005-0.2 ⁇ m, optionally 0.01-0.1 ⁇ m, and more optionally 0.04-0.08 ⁇ m.
  • the thickness of the coating layer meets the above range, it is conducive to further improving the cycle performance and rate performance of the cathode active material.
  • a second aspect of the application provides a method for preparing a cathode active material, which method includes the following steps:
  • step S2 Add the fast ion conductor precursor, metal compound conductive agent and dispersant polyvinylpyrrolidone into water and mix evenly, then add the primary particles of the lithium-rich manganese-based cathode active material precursor of step S1) into the water and mix evenly to obtain Suspensions of solid mixtures;
  • step S3 spray-dry the suspension of the solid mixture in step S2) for secondary granulation to obtain positive electrode active material precursor powder;
  • step S4 Mix the cathode active material precursor powder and the lithium source in step S3) evenly, and sinter them to obtain the cathode active material
  • the positive active material is a secondary particle formed by stacking primary particles, wherein the primary particle includes a lithium-rich manganese-based matrix material and a coating layer located on the surface of the lithium-rich manganese-based matrix material, and the coating layer includes Fast ion conductor and metal compound conductive agent.
  • the Dv50 of the primary particles of the lithium-rich manganese-based cathode active material precursor is 0.05-1.1 ⁇ m, optionally 0.1-0.4 ⁇ m.
  • the particle size of the primary particles of the precursor it is beneficial to obtain a cathode active material with improved rate performance and cycle performance.
  • the solid mixture includes primary particles of a fast ion conductor precursor, a metal compound conductive agent, and a lithium-rich manganese-based cathode active material precursor, wherein the fast ion conductor
  • the precursor is selected from one or more of silicon dioxide, lithium phosphate, lithium borate, niobium pentoxide, alumina, zirconium dioxide and lithium dihydrogen phosphate.
  • the fast ion conductor precursor is selected from One or more of silica, lithium phosphate, and lithium borate; optionally, the amount of the fast ion conductor is 0.4-16% by weight, optionally 1.5-9.5% by weight, based on the solid mixture by weight, and the metal compound conductive agent is selected from one or more of titanium carbide, titanium nitride and titanium boride; optionally, the amount of the metal compound conductive agent is 0.4-8% by weight, Optional is 0.8-5% by weight, based on the weight of the solid mixture.
  • the sintering atmosphere is oxygen, air or compressed air
  • the sintering temperature is 700-1000°C
  • the sintering time is 5-10 h.
  • a third aspect of the present application provides a positive electrode sheet.
  • 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 film layer includes the positive electrode activity of the first aspect of the application. material or a cathode active material prepared by the method of the second aspect of the present application, and the content of the cathode active material in the cathode film layer is more than 10% by weight, based on the total weight of the cathode film layer.
  • a fourth aspect of the application provides a secondary battery, which includes the cathode active material of the first aspect of the application or the cathode active material prepared according to the method of the second aspect of the application.
  • a fifth aspect of the present application provides a battery module including the secondary battery of the fourth aspect of the present application.
  • a sixth aspect of the present application provides a battery pack, which includes the battery module of the fifth aspect of the present application.
  • a seventh aspect of the present application provides an electrical device, which includes at least one selected from the group consisting of the secondary battery of the fourth aspect of the present application, the battery module of the fifth aspect of the present application, or the battery pack of the sixth aspect of the present application. A sort of.
  • the battery modules, battery packs and electrical devices of the present application include the secondary battery provided by the present application, and therefore have at least the same advantages as the secondary battery.
  • 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. Furthermore, 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 “a-b” 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
  • 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).
  • Lithium-rich manganese-based cathode materials are considered to be the preferred cathode materials for the next generation of high-specific-energy batteries due to their high specific capacity (>250mAh/g), low cost, and good thermal stability.
  • Lithium-rich manganese-based cathode materials mainly use environmentally friendly manganese elements, which have low nickel and cobalt content and may even be cobalt-free, effectively avoiding the problem of nickel and cobalt resources. At the same time, compared with cobalt and nickel, manganese is not only cheap And the reserves are abundant. However, the lithium ion diffusion coefficient of lithium-rich materials is low, resulting in poor rate performance.
  • a suitable surface coating layer can not only provide a fast transmission channel for lithium ions/electrons, but also isolate electrolysis Direct contact between the liquid and the cathode material to prevent the reaction between the two from deteriorating battery performance.
  • a single coating layer only has one property, that is, while improving ion conductivity, it may hinder the transmission of electrons and affect conductivity, and vice versa.
  • the carbon layer has good conductivity, but its lithium ion transport capacity is relatively low. Poor.
  • multi-layer coating means that the preparation process is more complicated, and the bonding strength between the coating layers is difficult to guarantee. As the cycle process proceeds, the coating layer and the base material may be separated, thus degrading the performance.
  • a first aspect of the present application provides a cathode active material.
  • the cathode active material is a secondary particle formed by stacking primary particles, wherein the primary particles include a lithium-rich manganese-based matrix material and a lithium-rich manganese-based base material located on the rich lithium-rich manganese base material.
  • a coating layer on the surface of the lithium manganese base material, the coating layer includes a fast ion conductor and a metal compound conductive agent.
  • the cathode active material of the present application is a secondary particle formed by stacking primary particles, and a homogeneous composite is constructed on the outer surface of the matrix material of the primary particles.
  • the coating layer includes a fast ion conductor and a metal compound conductive agent.
  • the fast ion conductor can effectively improve the ion transmission capability of the cathode active material
  • the metal compound conductive agent can effectively improve the electron transmission capability of the cathode active material. It forms a continuous ion and electron channel in the coating layer.
  • the cathode active material of the present application can be modified through surface coating to prevent direct contact between the cathode active material and the electrolyte, inhibit the occurrence of side reactions, and improve the cycle performance of the cathode active material.
  • the surface of each primary particle has The completed coating layer, even if the secondary particles are broken, will not seriously affect the cycle stability of the material.
  • the secondary particles are composed of multiple primary particles gathered together to form spherical or spherical-like particles; the primary particles are single particles with a Dv50 of about 0.05-1 ⁇ m and there is no obvious agglomeration between particles.
  • the fast ion conductor is selected from one or more of lithium silicate, lithium phosphate, lithium borate, lithium niobate, lithium aluminate, lithium zirconate and lithium pyrophosphate.
  • the fast ion conductor is selected from one or more of lithium silicate, lithium phosphate and lithium borate; optionally, the amount of the fast ion conductor is 0.5-20% by weight, optionally 2-12% by weight , based on the weight of the cathode active material.
  • the coating layer will be too thick, which is not conducive to the transmission efficiency of ions in the cathode active material; if the content of the fast ion conductor is too low, lithium ions cannot be effectively transported.
  • the metal compound conductive agent is selected from one or more of titanium carbide, titanium nitride and titanium boride; optionally, the amount of the metal compound conductive agent is 0.5-10% by weight. , optionally 1-6% by weight, based on the weight of the cathode active material.
  • the rate performance and cycle performance of the cathode active material can be further improved. If the content of the metal compound conductive agent is too high, the coating layer will be too thick, which is detrimental to the transmission efficiency of ions in the cathode active material; if the content of the metal compound conductive agent is too low, electrons cannot be effectively transported.
  • the weight ratio of the fast ion conductor to the metal compound conductive agent in the cathode active material is 1.3-3:1, optionally 1.7-2.7:1.
  • the cathode active material can have both high ionic conductivity and electronic conductivity, thereby further improving the cycle performance and performance of the cathode active material. magnification performance.
  • the chemical formula of the lithium-rich manganese-based matrix material is xLi 2 MnO 3 ⁇ (1-x)LiMO 2 , wherein M is selected from Fe, Al, Co, Mn, Ni, Cr, Ti , Mo, Nb, Zr, Sn, V, Mg, Cu, Zn, B, Na, Ca and Ru in one or more combinations, optionally, the M is selected from Co, Ni, Cr, One or a combination of one or more of V, Mo, Mn, Al, Nb and Ti, and 0 ⁇ x ⁇ 1.
  • the Dv50 of the positive active material is 5-20 ⁇ m, optionally 7-13 ⁇ m, and the Dv50 of the primary particles is 0.05-1 ⁇ m, optionally 0.1-0.4 ⁇ m.
  • the particle size of the positive active material is within the above range, the compacted density of the positive active material can be optimized, thereby further improving the performance of the positive active material.
  • the compacted density of the cathode active material under 5 tons of force is 2.4-3.4g/cm 3 , optionally 2.7-3.2g/cm 3 .
  • the higher the compaction density the greater the weight of the active material per unit volume. Therefore, increasing the compaction density is beneficial to increasing the volumetric energy density of the battery core.
  • the positive active material has a high compaction density and a high filling degree between particles, which is not only conducive to further improving the processing performance of the positive active material.
  • the compacted density can be measured according to GB/T 24533-2009.
  • the thickness of the coating layer is 0.005-0.2 ⁇ m, optionally 0.01-0.1 ⁇ m, and more optionally 0.04-0.08 ⁇ m.
  • the cathode active material can have improved cycle performance and rate performance. If the thickness of the coating layer is too thick, it will be detrimental to the transmission efficiency of electrons and ions; if the thickness of the coating layer is too thin, it will not be able to effectively transmit electrons and ions.
  • the weight a of the fast ion conductor in the positive active material and the weight b of the metal compound conductive agent satisfy the following: 2 ⁇ a*b/(a+b) ⁇ 4, optional Ground, 2.5 ⁇ a*b/(a+b) ⁇ 3.
  • a second aspect of the application provides a method for preparing a cathode active material, which method includes the following steps:
  • step S2 Add the fast ion conductor precursor, metal compound conductive agent and dispersant polyvinylpyrrolidone into water and mix evenly, then add the primary particles of the lithium-rich manganese-based cathode active material precursor of step S1) into the water and mix evenly to obtain Suspensions of solid mixtures;
  • step S3 spray-dry the suspension of the solid mixture in step S2) for secondary granulation to obtain positive electrode active material precursor powder;
  • step S4 Mix the cathode active material precursor powder and the lithium source in step S3) evenly, and sinter them to obtain the cathode active material
  • the positive active material is a secondary particle formed by stacking primary particles, wherein the primary particle includes a lithium-rich manganese-based matrix material and a coating layer located on the surface of the lithium-rich manganese-based matrix material, and the coating layer includes Fast ion conductor and metal compound conductive agent.
  • a homogeneous composite coating layer is constructed on the outer surface of the matrix material of the primary particles, which effectively improves the ion transmission capacity and electron transmission capacity of the positive electrode active material, thereby obtaining a positive electrode active material with improved rate performance. material; on the other hand, it can significantly improve the bonding strength between the coating layer and the base material, avoid the degradation of battery performance caused by the shedding of the coating layer caused by uneven stress during the cycle, and effectively improve the cycle performance of the cathode active material.
  • the Dv50 of the primary particles of the lithium-rich manganese-based cathode active material precursor is 0.05-1.1 ⁇ m, optionally 0.1-0.4 ⁇ m.
  • the particle size of the primary particles of the precursor it is beneficial to obtain a cathode active material with improved rate performance and cycle performance.
  • the crushing method includes one or more of grinding, jet crushing, mechanical mill crushing and high-energy ball milling.
  • the crushing method is high-energy ball milling.
  • the solid mixture in step S2), includes primary particles of a fast ion conductor precursor, a metal compound conductive agent, and a lithium-rich manganese-based cathode active material precursor, wherein the fast ion conductor
  • the precursor is selected from one or more of silicon dioxide, lithium phosphate, lithium borate, niobium pentoxide, alumina, zirconium dioxide and lithium dihydrogen phosphate.
  • the fast ion conductor precursor is selected from One or more of silica, lithium phosphate, and lithium borate; optionally, the amount of the fast ion conductor is 0.4-16% by weight, optionally 1.5-9.5% by weight, based on the solid mixture by weight, and the metal compound conductive agent is selected from one or more of titanium carbide, titanium nitride and titanium boride; optionally, the amount of the metal compound conductive agent is 0.4-8% by weight, Optional is 0.8-5% by weight, based on the weight of the solid mixture.
  • the sintering atmosphere is oxygen, air or compressed air
  • the sintering temperature is 700-1000°C, for example, it can be 700°C, 800°C, 900°C or 1000°C, etc. , but are not limited to the listed point values.
  • the sintering time is 5-10h. For example, it can be 5h, 6h, 7h, 8h, 9h or 10h, but is not limited to the listed point values. The same applies as long as the values are within the above range.
  • a third aspect of the present application provides a positive electrode sheet.
  • 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 film layer includes the positive electrode activity of the first aspect of the application. material or a cathode active material prepared by the method of the second aspect of the present application, and the content of the cathode active material in the cathode film layer is more than 10% by weight, based on the total weight of the cathode film layer.
  • a fourth aspect of the application provides a secondary battery, which includes the cathode active material of the first aspect of the application or the cathode active material prepared according to the method of the second aspect of the application.
  • a fifth aspect of the present application provides a battery module including the secondary battery of the fourth aspect of the present application.
  • a sixth aspect of the present application provides a battery pack, which includes the battery module of the fifth aspect of the present application.
  • a seventh aspect of the present application provides an electrical device, which includes at least one selected from the group consisting of the secondary battery of the fourth aspect of the present application, the battery module of the fifth aspect of the present application, or the battery pack of the sixth aspect of the present application. A sort of.
  • a secondary battery is provided.
  • a secondary battery typically includes a positive electrode plate, a negative electrode plate, an electrolyte and a separator.
  • active ions are inserted and detached back and forth between the positive and negative electrodes.
  • the electrolyte plays a role in conducting ions between the positive and negative electrodes.
  • the isolation film is placed between the positive electrode piece and the negative electrode piece. It mainly prevents the positive and negative electrodes from short-circuiting and allows ions to pass through.
  • 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 film layer includes the positive electrode active material of the first aspect of the present application.
  • the positive electrode current collector has two surfaces facing each other in its own 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.
  • the metal foil aluminum foil can 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 base layer.
  • the composite current collector can be formed by forming metal materials (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on polymer material substrates (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 cathode active material may also be a cathode active material known in the art for use in batteries.
  • the cathode active material may include at least one of the following materials: an olivine-structured lithium-containing phosphate, 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 of batteries can also be used.
  • These cathode active materials may be used alone or in combination of two or more, wherein the cathode active material of the first aspect of the application accounts for 85-100% and the other cathode active materials account for 0-15%.
  • lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO 2 ), lithium nickel oxides (such as LiNiO 2 ), lithium manganese oxides (such as LiMnO 2 , LiMn 2 O 4 ), lithium Nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (can also be abbreviated to NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (can also be abbreviated to NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (can also be abbreviated to NCM 622 ), LiNi At least one of 0.8 Co 0.1 Mn 0.1 O 2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as Li Li
  • the olivine structure contains Examples of lithium phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also referred to as LFP)), composites of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), lithium manganese phosphate and carbon. At least one of composite materials, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon.
  • the weight ratio of the positive electrode active material in the positive electrode film layer is 80-100% by weight, based on the total weight of the positive electrode film layer count.
  • the positive electrode film layer optionally further includes a binder.
  • the binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene At least one of ethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin.
  • the weight ratio of the binder in the positive electrode film layer is 0-20% by weight, based on the total weight of the positive electrode film layer.
  • the positive electrode film layer optionally further includes a conductive agent.
  • the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the weight ratio of the conductive agent in the positive electrode film layer is 0-20% by weight, based on the total weight of the positive electrode film layer.
  • the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components in a solvent (such as N -methylpyrrolidone), forming a positive electrode slurry; wherein the solid content of the positive electrode slurry is 40-80wt%, the viscosity at room temperature is adjusted to 5000-25000mPa ⁇ s, and the positive electrode slurry is coated on the positive electrode current collector, After drying, cold pressing and other processes, the positive electrode piece can be obtained.
  • the unit area density of the positive electrode powder coating is 150-350mg/m 2 and the compacted density of the positive electrode piece is 3.0-3.6g/cm 3. The optional 3.3-3.5g/cm 3 .
  • the calculation formula of the compacted density is
  • Compaction density coating surface density / (thickness of electrode piece after extrusion - thickness of current collector).
  • 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.
  • the negative active material may have an average particle diameter (D 10 ) of 1 ⁇ m to 15 ⁇ m, preferably 4 ⁇ m to 9 ⁇ m, an average particle diameter (D 50 ) of 12 ⁇ m to 22 ⁇ m, preferably 14 ⁇ m to 17 ⁇ m, and 26 ⁇ m to 40 ⁇ m, preferably Average particle size (D 90 ) of 30 ⁇ m-37 ⁇ m.
  • D 10 is the particle size corresponding to when the cumulative volume distribution percentage of the sample reaches 10%
  • D 50 is the particle size corresponding to when the cumulative volume distribution percentage of the sample reaches 50%
  • D 90 is the corresponding particle size when the cumulative volume distribution percentage of the sample reaches 90%. particle size.
  • the weight ratio of the negative active material in the negative electrode film layer is 70-100% by weight, based on the total weight of the negative electrode film layer.
  • the negative electrode film layer optionally further includes a binder.
  • the binder can be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), polysodium acrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), poly At least one of methacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • SBR styrene-butadiene rubber
  • PAA polyacrylic acid
  • PAAS polysodium acrylate
  • PAM polyacrylamide
  • PVA polyvinyl alcohol
  • SA sodium alginate
  • PMAA methacrylic acid
  • CMCS carboxymethyl chitosan
  • 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 weight ratio of the conductive agent in the negative electrode film layer is 0-20% by weight, based on the total weight of the negative electrode film layer.
  • the negative electrode film layer optionally includes other auxiliaries, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
  • the weight ratio of the other additives in the negative electrode film layer is 0-15% by weight, based on the total weight of the negative electrode film layer.
  • 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, wherein the solid content of the negative electrode slurry is 30-70wt%, and the viscosity at room temperature is adjusted to 2000-10000mPa ⁇ s; the negative electrode slurry is coated on the negative electrode current collector and dried , cold pressing and other processes, the negative electrode piece can be obtained.
  • the negative electrode powder coating unit area density is 75-220mg/m 2
  • the negative electrode plate compacted density is 1.2-2.0g/m 3 .
  • 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 salt may be selected from the group consisting of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonimide, lithium bistrifluoromethanesulfonimide, trifluoromethane At least one of lithium sulfonate, lithium difluorophosphate, lithium difluoroborate, lithium dioxaloborate, lithium difluorodioxalate phosphate and lithium tetrafluoroxalate phosphate.
  • the concentration of the electrolyte salt is usually 0.5-5mol/L.
  • the solvent may be selected from the group consisting of ethylene carbonate, propylene carbonate, methylethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, Butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate At least one of ester, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • 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 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 thickness of the isolation film is 6-40 ⁇ m, optionally 12-20 ⁇ m.
  • 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.
  • the secondary battery may include an outer packaging.
  • the outer packaging can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the secondary battery 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 bag, such as a bag-type soft bag.
  • the material of the soft bag may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.
  • FIG. 1 shows a square-structured secondary battery 5 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 can 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 those skilled in the art can select according to specific actual needs.
  • secondary batteries can be assembled into battery modules, and the number of secondary batteries contained in the battery module can be one or more. Those skilled in the art can select the specific number according to the application and capacity of the battery module.
  • FIG. 3 is a 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.
  • the number of battery modules contained in the battery pack can be one or more. Those skilled in the art can select the specific number 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 disposed in the battery box.
  • the battery box includes an upper box 2 and a lower box 3 .
  • the upper box 2 can be covered with 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 also provides an electrical device, which includes at least one of the secondary battery, battery module, or battery pack provided by the present application.
  • the secondary battery, battery module, or battery pack may be used as a power source for the electrical device, or may be used as an energy storage unit for the electrical 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, and electric golf carts). , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited to these.
  • a secondary battery, a battery module or a battery pack can be selected according to its usage requirements.
  • FIG. 6 is an electrical device as an example.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, etc.
  • a battery pack or battery module can be used.
  • the device may be a mobile phone, a tablet, a laptop, etc.
  • the device is usually required to be thin and light, and a secondary battery can be used as a power source.
  • a transition metal salt solution is prepared according to a molar ratio of Mn and Ni elements of 7:3. The concentration of the solution is 2 mol/L.
  • Salt solution, sodium carbonate solution and ammonia solution are pumped into the reaction kettle at the same time, and the pH of the reaction system is controlled by adjusting the feed flow rate v2 of the sodium carbonate solution to 9.5.
  • the temperature of the reaction system is maintained at 50°C and the stirring speed is 800 rpm/min. React for 20h.
  • the reaction slurry is aged for 10 hours, and then the precipitate is filtered, washed and dried to obtain the lithium-rich manganese-based cathode active material precursor Ni 0.3 Mn 0.7 CO 3 .
  • the lithium-rich manganese-based cathode active material precursor Ni 0.3 Mn 0.7 CO 3 (Dv50 is 8 ⁇ m) prepared above was crushed by high-energy ball milling in a nitrogen atmosphere to obtain primary particles (Dv50) of the lithium-rich manganese-based cathode active material precursor. is 0.3 ⁇ m).
  • Add the fast ion conductor precursor lithium borate, the metal compound conductive agent titanium boride and the dispersant polyvinylpyrrolidone to the water and stir at 800 rpm/min to mix evenly, and then add primary particles of the lithium-rich manganese-based cathode active material precursor to the water. , stir and mix evenly at 500 rpm/min to obtain a suspension of a solid mixture.
  • the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based cathode active material precursor in the solid mixture is 6.1:3.1:90.8.
  • the suspension of the above solid mixture was then spray-dried and granulated twice (manufacturer: Buqi; model: B-290).
  • the air inlet temperature of the spray drying was 250°C and the nozzle diameter was 600 ⁇ m to obtain the positive electrode active material precursor. powder.
  • the above-mentioned positive electrode active material precursor powder and lithium source lithium carbonate were evenly mixed at a weight ratio of 100:50, and then sintered at 800°C for 8 hours in an air atmosphere to obtain the positive electrode active material.
  • [Positive electrode sheet] Mix the above positive active material, conductive agent acetylene black, and binder polyvinylidene fluoride (PVDF) in the N-methylpyrrolidone solvent system in a weight ratio of 92:2.5:5.5, and then coat Put it on aluminum foil, dry it, and cold-press it to obtain the positive electrode piece.
  • the coating amount is 0.4g/cm 2 and the compacted density is 2.4g/cm 3 .
  • [Negative electrode sheet] Mix the negative active material artificial graphite, conductive agent carbon black, and binder styrene-butadiene rubber (SBR) in deionized water at a weight ratio of 92:2:6, then apply it on the copper foil and dry it , cold pressing to obtain the negative electrode piece.
  • the coating amount is 0.2g/cm 2 and the compacted density is 1.7g/cm 3 .
  • isolation film The isolation film is purchased from Cellgard Company, the model is cellgard2400.
  • Electrode Mix ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) in a volume ratio of 1:1:1, and then uniformly dissolve LiPF 6 in the above solution to obtain electrolysis liquid, in which the concentration of LiPF 6 is 1mol/L.
  • the bare battery core is placed in the outer packaging, electrolyte is injected and packaged, and then through chemical formation and volume separation, a lithium-ion secondary full battery (hereinafter also referred to as "full battery”) is obtained.
  • the length ⁇ width ⁇ height of the full battery 148mm ⁇ 28.5mm ⁇ 97.5mm, and the group margin of the battery is 91.0%.
  • the preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor in the solid mixture is 0.4:3.0: 96.6.
  • the preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor in the solid mixture is 1.5:3.0: 95.5.
  • the preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor in the solid mixture is 5.4:3.0: 91.6.
  • the preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor in the solid mixture is 9.3:3.1: 87.6.
  • the preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor in the solid mixture is 15.7:3.2: 81.1.
  • the preparation of the secondary battery is the same as in Example 1, except that the Dv50 of the lithium-rich manganese-based cathode active material precursor Ni 0.3 Mn 0.7 CO 3 is 5 ⁇ m.
  • the preparation of the secondary battery is the same as in Example 1, except that the Dv50 of the lithium-rich manganese-based cathode active material precursor Ni 0.3 Mn 0.7 CO 3 is 13 ⁇ m.
  • the preparation of the secondary battery is the same as in Example 1, except that the Dv50 of the lithium-rich manganese-based cathode active material precursor Ni 0.3 Mn 0.7 CO 3 is 20 ⁇ m.
  • the preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor (Dv50 is 7 ⁇ m) in the solid mixture is 6.0:0.4:93.6.
  • the preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor (Dv50 is 7 ⁇ m) in the solid mixture is 6.0:0.8:93.2.
  • the preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor (Dv50 is 8 ⁇ m) in the solid mixture is 6.1:2.3:91.6.
  • the preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor (Dv50 is 8 ⁇ m) in the solid mixture is 6.2:4.6:89.2.
  • the preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor (Dv50 is 10 ⁇ m) in the solid mixture is 6.2:7.8:86.0.
  • the preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the fast ion conductor precursor is silicon dioxide.
  • the preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the fast ion conductor precursor is lithium phosphate.
  • the preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the metal compound conductive agent is titanium nitride.
  • the preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the metal compound conductive agent is titanium carbide.
  • the preparation of the secondary battery is the same as in Example 1, except that in (2) the preparation of the positive electrode active material, the lithium-rich manganese-based positive electrode active material precursor Ni 0.3 Mn 0.7 CO 3 obtained in (1) is directly mixed with the lithium source After mixing lithium carbonate evenly with a weight ratio of 100:50, it was sintered at 800°C for 8 hours in an air atmosphere to obtain a lithium-rich manganese-based cathode active material 0.4Li 2 MnO 3 ⁇ 0.6LiNi 0.5 Mn 0.5 O 2 , and use the rich Lithium manganese-based cathode active materials are used to prepare button batteries.
  • the particle size of the cathode active material is measured according to GB/T 19077.1-2016/ISO 13320:2009 (particle size distribution laser diffraction method). Take a clean beaker, add an appropriate amount of the above positive active material, add an appropriate amount of pure water, and ultrasonic at 120W/5min to ensure that the material powder is completely dispersed in the water.
  • the solution is poured into the injection tower of the laser particle size analyzer (Malvern Company, model: Mastersizer3000) and then circulated to the test optical system with the solution.
  • the particles are irradiated by the laser beam and can be obtained by receiving and measuring the energy distribution of the scattered light.
  • Particle size distribution characteristics (opacity: 8-12%), read the corresponding value of Dv50.
  • a line scan (Line Scan Analysis) is performed on the materials in the display screen.
  • the acceleration voltage is 50kV
  • the amplification factor is 100kx
  • the beam current is between 500 and 1000pA.
  • the coating layer and the surface of the lithium-rich manganese-based base material are determined according to the proportion of the corresponding element numbers, so that the thickness of the coating layer can be obtained.
  • the thickness of the coating layer was measured at 5 randomly selected positions on the positive active material particles, and the arithmetic average of the measurement results was taken.
  • the secondary batteries of each example and comparative example were charged to 4.35V at a constant current rate of 0.1C, then charged at a constant voltage until the current was 0.05C, left to stand for 5 minutes, and then discharged at a constant current rate of 0.1C to 2V, record the discharge capacity at this time, which is the 0.1C discharge capacity; let it stand for 30 minutes, then charge the secondary battery with a constant current at a rate of 1C to 4.35V, then charge with a constant voltage until the current is 0.05C, let it stand for 5 minutes, and then Discharge to 2V at a constant current rate of 1C, and record the discharge capacity at this time, which is the 1C discharge capacity;
  • the secondary batteries of each example and comparative example were discharged to 2.5V at 1/3C. Let it stand for 5 minutes, charge to 4.3V at 1/3C, and then charge at a constant voltage of 4.3V until the current is ⁇ 0.05mA. Let it stand for 5 minutes, and record the charging capacity at this time as C0. Discharge to 2.5V according to 1/3C, let it sit for 5 minutes, then charge to 4.3V according to 3C, let it stand for 5 minutes, and record the charging capacity at this time as C1.
  • the 3C charging constant current ratio is C1/C0*100%.
  • the cathode active material of the present application has better cycle performance and rate performance. This is precisely because of the The cathode active material is a secondary particle formed by stacking primary particles. A homogeneous composite coating layer forming a continuous ion and electron channel is constructed on the outer surface of the matrix material of the primary particle, which is conducive to the transmission of ions and electrons.

Abstract

Provided in the present application is a positive electrode active material. The positive electrode active material is made of secondary particles that are formed by stacking primary particles, wherein the primary particles comprise a lithium-rich manganese-based matrix material and a coating layer, which is located on the surface of the lithium-rich manganese-based matrix material, the coating layer comprising a fast ion conductor and a metal compound conductive agent. The positive electrode active material has improved cycling performance and rate capability. Further provided in the present application are a preparation method for the positive electrode active material, and a positive electrode plate, a secondary battery, a battery module, a battery pack, and an electric device which comprise the positive electrode active material of the present application.

Description

正极活性材料及其制备方法、正极极片、二次电池、电池模块、电池包和用电装置Cathode active material and preparation method thereof, cathode plate, secondary battery, battery module, battery pack and electrical device 技术领域Technical field
本申请涉及锂电池技术领域，尤其涉及一种正极活性材料及其制备方法，及包括该正极活性材料的正极极片、二次电池、电池模块、电池包和用电装置。The present application relates to the technical field of lithium batteries, and in particular to a positive active material and a preparation method thereof, as well as a positive electrode sheet, a secondary battery, a battery module, a battery pack and an electrical device including the positive active material.
背景技术Background technique
近年来，随着锂离子电池的应用范围越来越广泛，锂离子电池广泛应用于水力、火力、风力和太阳能电站等储能电源***，以及电动工具、电动自行车、电动摩托车、电动汽车、军事装备、航空航天等多个领域。由于锂离子电池取得了极大的发展，因此对其能量密度、循环性能和安全性能等也提出了更高的要求。In recent years, as the application range of lithium-ion batteries has become more and more extensive, lithium-ion batteries are widely used in energy storage power systems such as hydraulic, thermal, wind and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, Military equipment, aerospace and other fields. Due to the great development of lithium-ion batteries, higher requirements have been put forward for their energy density, cycle performance and safety performance.
锂离子电池关键材料的性能是电池性能的最终决定性因素，正极材料的研究一直是电池研究关注的热点。目前常见的正极材料有层状结构材料(例如钴酸锂、锰酸锂、镍酸锂等)、尖晶石结构材料、聚阴离子型材料、三元材料以及目前备受人们关注的富锂材料等。但由这些正极材料制备的锂离子电池体系还存在能量密度低、成本高、安全性差等问题，无法满足人们日益增长的对电池快速充电、循环稳定性、安全性等的需求，因此，需要采取一定策略来优化正极材料，从而改善二次电池循环性能、倍率性能和安全性能。The performance of key materials in lithium-ion batteries is the ultimate decisive factor in battery performance. Research on cathode materials has always been a focus of battery research. Common cathode materials currently include layered structure materials (such as lithium cobalt oxide, lithium manganate, lithium nickel oxide, etc.), spinel structure materials, polyanionic materials, ternary materials, and lithium-rich materials that are currently attracting much attention. wait. However, lithium-ion battery systems prepared from these cathode materials still have problems such as low energy density, high cost, and poor safety. They cannot meet people's growing needs for battery fast charging, cycle stability, safety, etc. Therefore, it is necessary to adopt Certain strategies are used to optimize cathode materials to improve secondary battery cycle performance, rate performance and safety performance.
发明内容Contents of the invention
本申请是鉴于上述课题而进行的，其目的在于，提供一种正极活性材料，该正极活性材料具有改善的循环性能和倍率性能，并提供该正极活性材料的制备方法以及包含本申请正极活性材料的正极极片、二次电池、电池模块、电池包和用电装置。This application was conducted in view of the above-mentioned issues, and its purpose is to provide a cathode active material with improved cycle performance and rate performance, and to provide a preparation method of the cathode active material and a cathode active material containing the cathode active material of the application. cathode plates, secondary batteries, battery modules, battery packs and electrical devices.
为了达到上述目的，本申请的第一方面提供了一种正极活性材料， 所述正极活性材料为由一次颗粒堆叠形成的二次颗粒，其中所述一次颗粒包括富锂锰基基体材料和位于所述富锂锰基基体材料表面的包覆层，所述包覆层包括快离子导体和金属化合物导电剂。In order to achieve the above objects, a first aspect of the present application provides a cathode active material. The cathode active material is a secondary particle formed by stacking primary particles, wherein the primary particles include a lithium-rich manganese-based matrix material and a The coating layer on the surface of the lithium-rich manganese base material includes a fast ion conductor and a metal compound conductive agent.
由此，相对于现有技术，本申请的正极活性材料具有改善的循环性能和倍率性能。Therefore, compared with the prior art, the cathode active material of the present application has improved cycle performance and rate performance.
在任意实施方式中，所述快离子导体选自硅酸锂、磷酸锂、硼酸锂、铌酸锂、铝酸锂、锆酸锂和焦磷酸锂中的一种或多种，可选地，所述快离子导体选自硅酸锂、磷酸锂和硼酸锂中的一种或多种；可选地，所述快离子导体的量为0.5-20重量％、可选为2-12重量％，基于所述正极活性材料的重量计。通过选择上述快离子导体且使其含量满足上述范围，可以进一步改善正极活性材料的倍率性能和循环性能。In any embodiment, the fast ion conductor is selected from one or more of lithium silicate, lithium phosphate, lithium borate, lithium niobate, lithium aluminate, lithium zirconate and lithium pyrophosphate, optionally, The fast ion conductor is selected from one or more of lithium silicate, lithium phosphate and lithium borate; optionally, the amount of the fast ion conductor is 0.5-20% by weight, optionally 2-12% by weight , based on the weight of the cathode active material. By selecting the above-mentioned fast ion conductor and making its content satisfy the above-mentioned range, the rate performance and cycle performance of the cathode active material can be further improved.
在任意实施方式中，所述金属化合物导电剂选自碳化钛、氮化钛和硼化钛中的一种或多种；可选地，所述金属化合物导电剂的量为0.5-10重量％、可选为1-6重量％，基于所述正极活性材料的重量计。通过选择上述金属化合物导电剂且使其含量满足上述范围，可以进一步改善正极活性材料的倍率性能和循环性能。In any embodiment, the metal compound conductive agent is selected from one or more of titanium carbide, titanium nitride and titanium boride; optionally, the amount of the metal compound conductive agent is 0.5-10% by weight. , optionally 1-6% by weight, based on the weight of the cathode active material. By selecting the above metal compound conductive agent and making the content satisfy the above range, the rate performance and cycle performance of the cathode active material can be further improved.
在任意实施方式中，所述正极活性材料中的所述快离子导体与所述金属化合物导电剂的重量比为1.3-3:1，可选为1.7-2.7:1。通过使所述快离子导体与所述金属化合物导电剂的重量比满足上述范围，可以进一步改善正极活性材料的倍率性能和循环性能。In any embodiment, the weight ratio of the fast ion conductor to the metal compound conductive agent in the cathode active material is 1.3-3:1, optionally 1.7-2.7:1. By making the weight ratio of the fast ion conductor to the metal compound conductive agent satisfy the above range, the rate performance and cycle performance of the cathode active material can be further improved.
在任意实施方式中，所述富锂锰基基体材料的化学式为xLi 2MnO 3·(1-x)LiMO 2，其中所述M为选自Fe、Al、Co、Mn、Ni、Cr、Ti、Mo、Nb、Zr、Sn、V、Mg、Cu、Zn、B、Na、Ca和Ru中的一种或多种的组合，可选地，所述M为选自Co、Ni、Cr、V、Mo、Mn、Al、Nb和Ti中的一种或多种的组合，且0＜x＜1。 In any embodiment, the chemical formula of the lithium-rich manganese-based matrix material is xLi 2 MnO 3 ·(1-x)LiMO 2 , wherein M is selected from Fe, Al, Co, Mn, Ni, Cr, Ti , Mo, Nb, Zr, Sn, V, Mg, Cu, Zn, B, Na, Ca and Ru in one or more combinations, optionally, the M is selected from Co, Ni, Cr, One or a combination of one or more of V, Mo, Mn, Al, Nb and Ti, and 0<x<1.
在任意实施方式中，所述正极活性材料的Dv50为5-20μm、可选为7-13μm，所述一次颗粒的Dv50为0.05-1μm、可选为0.1-0.4μm。当所述正极活性材料的粒径在上述范围内时，能够使得所述正极活性材料的压实密度最优化，从而进一步改善正极活性材料的性能。In any embodiment, the Dv50 of the positive active material is 5-20 μm, optionally 7-13 μm, and the Dv50 of the primary particles is 0.05-1 μm, optionally 0.1-0.4 μm. When the particle size of the positive active material is within the above range, the compacted density of the positive active material can be optimized, thereby further improving the performance of the positive active material.
在任意实施方式中，所述正极活性材料在5吨力下的压实密度为2.4-3.4g/cm 3，可选为2.7-3.2g/cm 3。当所述正极活性材料的压实密度 在上述范围时，正极活性材料颗粒之间填充度高，有利于进一步改善正极活性材料的加工性能。 In any embodiment, the compacted density of the positive active material under 5 tons of force is 2.4-3.4g/cm 3 , optionally 2.7-3.2g/cm 3 . When the compacted density of the cathode active material is within the above range, the filling degree between the particles of the cathode active material is high, which is beneficial to further improving the processing performance of the cathode active material.
在任意实施方式中，所述包覆层的厚度为0.005-0.2μm、可选为0.01-0.1μm，更可选为0.04-0.08μm。包覆层的厚度满足上述范围时，有利于进一步改善正极活性材料的循环性能和倍率性能。In any embodiment, the thickness of the coating layer is 0.005-0.2 μm, optionally 0.01-0.1 μm, and more optionally 0.04-0.08 μm. When the thickness of the coating layer meets the above range, it is conducive to further improving the cycle performance and rate performance of the cathode active material.
本申请的第二方面提供一种正极活性材料的制备方法，所述方法包括以下步骤：A second aspect of the application provides a method for preparing a cathode active material, which method includes the following steps:
S1)将富锂锰基正极活性材料前驱体在惰性气氛中破碎，得到富锂锰基正极活性材料前驱体的一次颗粒；S1) Crush the lithium-rich manganese-based cathode active material precursor in an inert atmosphere to obtain primary particles of the lithium-rich manganese-based cathode active material precursor;
S2)将快离子导体前驱体、金属化合物导电剂和分散剂聚乙烯吡咯烷酮加入水中并混合均匀，再向其中加入步骤S1)的富锂锰基正极活性材料前驱体的一次颗粒，混合均匀，得到固体混合物的悬浊液；S2) Add the fast ion conductor precursor, metal compound conductive agent and dispersant polyvinylpyrrolidone into water and mix evenly, then add the primary particles of the lithium-rich manganese-based cathode active material precursor of step S1) into the water and mix evenly to obtain Suspensions of solid mixtures;
S3)将步骤S2)的固体混合物的悬浊液经喷雾干燥二次造粒，得到正极活性材料前驱体粉末；S3) spray-dry the suspension of the solid mixture in step S2) for secondary granulation to obtain positive electrode active material precursor powder;
S4)将步骤S3)的正极活性材料前驱体粉末与锂源混合均匀，经烧结，得到正极活性材料，S4) Mix the cathode active material precursor powder and the lithium source in step S3) evenly, and sinter them to obtain the cathode active material,
所述正极活性材料为由一次颗粒堆叠形成的二次颗粒，其中所述一次颗粒包括富锂锰基基体材料和位于所述富锂锰基基体材料表面的包覆层，所述包覆层包括快离子导体和金属化合物导电剂。The positive active material is a secondary particle formed by stacking primary particles, wherein the primary particle includes a lithium-rich manganese-based matrix material and a coating layer located on the surface of the lithium-rich manganese-based matrix material, and the coating layer includes Fast ion conductor and metal compound conductive agent.
通过上述方法，可以获得具有改善的倍率性能和循环性能的正极活性材料。Through the above method, a cathode active material with improved rate performance and cycle performance can be obtained.
在任意实施方式中，在所述步骤S1)中，所述富锂锰基正极活性材料前驱体的一次颗粒的Dv50为0.05-1.1μm、可选为0.1-0.4μm。通过控制前驱体的一次颗粒的粒径，有利于获得具有改善的倍率性能和循环性能的正极活性材料。In any embodiment, in step S1), the Dv50 of the primary particles of the lithium-rich manganese-based cathode active material precursor is 0.05-1.1 μm, optionally 0.1-0.4 μm. By controlling the particle size of the primary particles of the precursor, it is beneficial to obtain a cathode active material with improved rate performance and cycle performance.
在任意实施方式中，在所述步骤S2)中，所述固体混合物包含快离子导体前驱体、金属化合物导电剂和富锂锰基正极活性材料前驱体的一次颗粒，其中，所述快离子导体前驱体选自二氧化硅、磷酸锂、硼酸锂、五氧化二铌、氧化铝、二氧化锆和磷酸二氢锂中的一种或多种，可选地，所述快离子导体前驱体选自二氧化硅、磷酸锂、硼酸锂中的一种或多种；可选地，所述快离子导体的量为0.4-16重量％、可选为1.5-9.5重量％， 基于所述固体混合物的重量计，且所述金属化合物导电剂选自碳化钛、氮化钛和硼化钛中的一种或多种；可选地，所述金属化合物导电剂的量为0.4-8重量％、可选为0.8-5重量％，基于所述固体混合物的重量计。通过选择上述的快离子导体前驱体和金属化合物导电剂，并使它们的含量满足上述范围，有利于获得具有改善的倍率性能和循环性能的正极活性材料。In any embodiment, in step S2), the solid mixture includes primary particles of a fast ion conductor precursor, a metal compound conductive agent, and a lithium-rich manganese-based cathode active material precursor, wherein the fast ion conductor The precursor is selected from one or more of silicon dioxide, lithium phosphate, lithium borate, niobium pentoxide, alumina, zirconium dioxide and lithium dihydrogen phosphate. Optionally, the fast ion conductor precursor is selected from One or more of silica, lithium phosphate, and lithium borate; optionally, the amount of the fast ion conductor is 0.4-16% by weight, optionally 1.5-9.5% by weight, based on the solid mixture by weight, and the metal compound conductive agent is selected from one or more of titanium carbide, titanium nitride and titanium boride; optionally, the amount of the metal compound conductive agent is 0.4-8% by weight, Optional is 0.8-5% by weight, based on the weight of the solid mixture. By selecting the above-mentioned fast ion conductor precursor and metal compound conductive agent and making their contents meet the above range, it is beneficial to obtain a cathode active material with improved rate performance and cycle performance.
在任意实施方式中，在所述步骤S4)中，所述烧结的气氛为氧气、空气或压缩空气，烧结温度为700-1000℃，烧结时间为5-10h。通过控制烧结温度和烧结时间，能够使烧结后材料的结晶度更高，有利于获得具有改善的倍率性能和循环性能的正极活性材料。In any embodiment, in step S4), the sintering atmosphere is oxygen, air or compressed air, the sintering temperature is 700-1000°C, and the sintering time is 5-10 h. By controlling the sintering temperature and sintering time, the crystallinity of the sintering material can be higher, which is beneficial to obtaining cathode active materials with improved rate performance and cycle performance.
本申请的第三方面提供一种正极极片，所述正极极片包括正极集流体以及设置在正极集流体至少一个表面的正极膜层，所述正极膜层包括本申请第一方面的正极活性材料或通过本申请第二方面的方法制备的正极活性材料，并且所述正极活性材料在所述正极膜层中的含量为10重量％以上，基于所述正极膜层的总重量计。A third aspect of the present application provides a positive electrode sheet. 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 film layer includes the positive electrode activity of the first aspect of the application. material or a cathode active material prepared by the method of the second aspect of the present application, and the content of the cathode active material in the cathode film layer is more than 10% by weight, based on the total weight of the cathode film layer.
本申请的第四方面提供一种二次电池，其包括本申请第一方面的正极活性材料或根据本申请第二方面的方法制备的正极活性材料。A fourth aspect of the application provides a secondary battery, which includes the cathode active material of the first aspect of the application or the cathode active material prepared according to the method of the second aspect of the application.
本申请的第五方面提供一种电池模块，其包括本申请的第四方面的二次电池。A fifth aspect of the present application provides a battery module including the secondary battery of the fourth aspect of the present application.
本申请的第六方面提供一种电池包，其包括本申请的第五方面的电池模块。A sixth aspect of the present application provides a battery pack, which includes the battery module of the fifth aspect of the present application.
本申请的第七方面提供一种用电装置，其包括选自本申请的第四方面的二次电池、本申请的第五方面的电池模块或本申请的第六方面的电池包中的至少一种。A seventh aspect of the present application provides an electrical device, which includes at least one selected from the group consisting of the secondary battery of the fourth aspect of the present application, the battery module of the fifth aspect of the present application, or the battery pack of the sixth aspect of the present application. A sort of.
本申请的电池模块、电池包和用电装置包括本申请提供的二次电池，因此至少具有与所述二次电池相同的优势。The battery modules, battery packs and electrical devices of the present application include the secondary battery provided by the present application, and therefore have at least the same advantages as the secondary battery.
附图说明Description of drawings
图1是本申请一实施方式的二次电池的示意图。FIG. 1 is a schematic diagram of a secondary battery according to an embodiment of the present application.
图2是图1所示的本申请一实施方式的二次电池的分解图。FIG. 2 is an exploded view of the secondary battery according to the embodiment of the present application shown in FIG. 1 .
图3是本申请一实施方式的电池模块的示意图。Figure 3 is a schematic diagram of a battery module according to an embodiment of the present application.
图4是本申请一实施方式的电池包的示意图。Figure 4 is a schematic diagram of a battery pack according to an embodiment of the present application.
图5是图4所示的本申请一实施方式的电池包的分解图。FIG. 5 is an exploded view of the battery pack according to an embodiment of the present application shown in FIG. 4 .
图6是本申请一实施方式的二次电池用作电源的用电装置的示意图。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.
附图标记说明：Explanation of reference symbols:
1电池包；2上箱体；3下箱体；4电池模块；5二次电池；51壳体；52电极组件；53顶盖组件1 battery pack; 2 upper box; 3 lower box; 4 battery module; 5 secondary battery; 51 shell; 52 electrode assembly; 53 top cover assembly
具体实施方式Detailed ways
以下，适当地参照附图详细说明具体公开了本申请的正极活性材料及其制备方法、正极极片、二次电池、电池模块、电池包和电学装置的实施方式。但是会有省略不必要的详细说明的情况。例如，有省略对已众所周知的事项的详细说明、实际相同结构的重复说明的情况。这是为了避免以下的说明不必要地变得冗长，便于本领域技术人员的理解。此外，附图及以下说明是为了本领域技术人员充分理解本申请而提供的，并不旨在限定权利要求书所记载的主题。Hereinafter, embodiments specifically disclosing the cathode active material and its preparation method, the cathode tab, the secondary battery, the battery module, the battery pack, and the electrical device of the present application will be described in detail with appropriate reference to the accompanying drawings. However, unnecessary detailed explanations may be omitted. For example, detailed descriptions of well-known matters may be omitted, or descriptions of substantially the same structure may be repeated. This is to prevent the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application, and are not intended to limit the subject matter described in the claims.
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110的范围，理解为60-110和80-120的范围也是预料到的。此外，如果列出的最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。在本申请中，除非有其他说明，数值范围“a-b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。"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. Furthermore, 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. In this application, unless stated otherwise, the numerical range "a-b" represents an abbreviated representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, 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. In addition, when stating that a certain parameter is an integer ≥ 2, it is equivalent to disclosing that the parameter is an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。If there is no special description, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions.
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以 相互组合形成新的技术方案。If there is no special description, all technical features and optional technical features of this application can be combined with each other to form new technical solutions.
如果没有特别的说明，本申请所提到的“包括”和“包含”表示开放式，也可以是封闭式。例如，所述“包括”和“包含”可以表示还可以包括或包含没有列出的其他组分，也可以仅包括或包含列出的组分。If there is no special explanation, the words "include" and "include" mentioned in this application represent open expressions, which may also be closed expressions. For example, "comprising" and "comprising" may mean that other components not listed may also be included or included, or only the listed components may be included or included.
如果没有特别的说明，在本申请中，术语“或”是包括性的。举例来说，短语“A或B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B都为真(或存在)。In this application, the term "or" is inclusive unless otherwise specified. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, 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).
富锂锰基正极材料是因其比容量高(＞250mAh/g)、成本低廉、热稳定好等优点，被认为是下一代高比能电池首选的正极材料。富锂锰基正极材料所使用的主要为环境友好的锰元素，其镍钴含量低，甚至可以不含钴，有效规避了镍钴资源的问题，同时，与钴、镍相比锰不仅价格低廉并且储量丰富。但是，富锂材料锂离子扩散系数较低，导致其倍率性能较差，且在充放电循环过程中金属离子发生迁移，由层状结构逐步向尖晶石结构转变，进而导致比容量和放电电压逐步衰减。研究表明，富锂锰基材料的结构相变是由表层逐步向体相延伸。所以，构建一个稳定的表面结构至关重要，表面包覆是改善正极材料电化学性能的有效方法，一个合适的表面包覆层既可以为锂离子/电子提供快速的传输通道，又可以隔绝电解液与正极材料的直接接触，避免二者反应劣化电池性能。一般情况下单一的包覆层只具备一种属性，即提升离子导的同时可能会阻碍电子的传输，影响导电性，反之亦然，例如碳层的导电性好，但是其锂离子传输能力相对较差。另外多层包覆意味着其制备工艺更加复杂，各包覆层之间的结合强度难以保证，随着循环过程的进行可能会出现包覆层与基体材料的分离，从而劣化性能。Lithium-rich manganese-based cathode materials are considered to be the preferred cathode materials for the next generation of high-specific-energy batteries due to their high specific capacity (>250mAh/g), low cost, and good thermal stability. Lithium-rich manganese-based cathode materials mainly use environmentally friendly manganese elements, which have low nickel and cobalt content and may even be cobalt-free, effectively avoiding the problem of nickel and cobalt resources. At the same time, compared with cobalt and nickel, manganese is not only cheap And the reserves are abundant. However, the lithium ion diffusion coefficient of lithium-rich materials is low, resulting in poor rate performance. During the charge and discharge cycle, metal ions migrate and gradually transform from a layered structure to a spinel structure, which in turn results in specific capacity and discharge voltage. gradually decay. Research shows that the structural phase transition of lithium-rich manganese-based materials gradually extends from the surface layer to the bulk phase. Therefore, it is crucial to build a stable surface structure. Surface coating is an effective method to improve the electrochemical performance of cathode materials. A suitable surface coating layer can not only provide a fast transmission channel for lithium ions/electrons, but also isolate electrolysis Direct contact between the liquid and the cathode material to prevent the reaction between the two from deteriorating battery performance. Generally speaking, a single coating layer only has one property, that is, while improving ion conductivity, it may hinder the transmission of electrons and affect conductivity, and vice versa. For example, the carbon layer has good conductivity, but its lithium ion transport capacity is relatively low. Poor. In addition, multi-layer coating means that the preparation process is more complicated, and the bonding strength between the coating layers is difficult to guarantee. As the cycle process proceeds, the coating layer and the base material may be separated, thus degrading the performance.
针对上述问题，本申请第一方面提供了一种正极活性材料，所述正极活性材料为由一次颗粒堆叠形成的二次颗粒，其中所述一次颗粒包括富锂锰基基体材料和位于所述富锂锰基基体材料表面的包覆层，所述包覆层包括快离子导体和金属化合物导电剂。In response to the above problems, a first aspect of the present application provides a cathode active material. The cathode active material is a secondary particle formed by stacking primary particles, wherein the primary particles include a lithium-rich manganese-based matrix material and a lithium-rich manganese-based base material located on the rich lithium-rich manganese base material. A coating layer on the surface of the lithium manganese base material, the coating layer includes a fast ion conductor and a metal compound conductive agent.
虽然机理尚不明确，但本申请人意外地发现：一方面，本申请的正极活性材料是由一次颗粒堆叠形成的二次颗粒，在所述一次颗粒的基体材料外表面构建一种均质复合包覆层，该包覆层包括快离子导体和金属化 合物导电剂，其中，快离子导体可以有效提升正极活性材料的离子传输能力，金属化合物导电剂可以有效提升正极活性材料的电子传输能力，两者在包覆层中形成连续的离子和电子通道，与常规多层包覆相比，有效降低了界面阻抗，并避免了电子在快离子导体包覆层、离子在导电包覆层传输能力差的问题，从而同步改善了正极活性材料的离子电导和电子电导，使得正极活性材料的倍率性能得到提升。另一方面，本申请的正极活性材料可以通过表面包覆改性可以阻止正极活性材料与电解液的直接接触，抑制副反应的发生，提升正极活性材料的循环性能，同时单个一次颗粒表面均有完成的包覆层，即使二次颗粒破碎，也不会严重影响材料的循环稳定性。Although the mechanism is not yet clear, the applicant unexpectedly discovered that: on the one hand, the cathode active material of the present application is a secondary particle formed by stacking primary particles, and a homogeneous composite is constructed on the outer surface of the matrix material of the primary particles. The coating layer includes a fast ion conductor and a metal compound conductive agent. The fast ion conductor can effectively improve the ion transmission capability of the cathode active material, and the metal compound conductive agent can effectively improve the electron transmission capability of the cathode active material. It forms a continuous ion and electron channel in the coating layer. Compared with conventional multi-layer coating, it effectively reduces the interface impedance and avoids the poor transmission ability of electrons in the fast ion conductor coating layer and ions in the conductive coating layer. problem, thus simultaneously improving the ionic conductivity and electronic conductivity of the cathode active material, thereby improving the rate performance of the cathode active material. On the other hand, the cathode active material of the present application can be modified through surface coating to prevent direct contact between the cathode active material and the electrolyte, inhibit the occurrence of side reactions, and improve the cycle performance of the cathode active material. At the same time, the surface of each primary particle has The completed coating layer, even if the secondary particles are broken, will not seriously affect the cycle stability of the material.
在本申请中，所述二次颗粒由多个一次颗粒聚集在一起形成球状或类球状颗粒；所述一次颗粒为Dv50约0.05-1μm的单个颗粒且颗粒之间无明显团聚。In this application, the secondary particles are composed of multiple primary particles gathered together to form spherical or spherical-like particles; the primary particles are single particles with a Dv50 of about 0.05-1 μm and there is no obvious agglomeration between particles.
在一些实施方式中，所述快离子导体选自硅酸锂、磷酸锂、硼酸锂、铌酸锂、铝酸锂、锆酸锂和焦磷酸锂中的一种或多种，可选地，所述快离子导体选自硅酸锂、磷酸锂和硼酸锂中的一种或多种；可选地，所述快离子导体的量为0.5-20重量％、可选为2-12重量％，基于所述正极活性材料的重量计。通过选择上述快离子导体且使其含量满足上述范围，可以进一步改善正极活性材料的倍率性能和循环性能。若快离子导体的含量过高，会导致包覆层过厚而不利于正极活性材料中离子的传输效率；若快离子导体的含量过低，则无法对锂离子进行有效输送。In some embodiments, the fast ion conductor is selected from one or more of lithium silicate, lithium phosphate, lithium borate, lithium niobate, lithium aluminate, lithium zirconate and lithium pyrophosphate. Alternatively, The fast ion conductor is selected from one or more of lithium silicate, lithium phosphate and lithium borate; optionally, the amount of the fast ion conductor is 0.5-20% by weight, optionally 2-12% by weight , based on the weight of the cathode active material. By selecting the above-mentioned fast ion conductor and making its content satisfy the above-mentioned range, the rate performance and cycle performance of the cathode active material can be further improved. If the content of the fast ion conductor is too high, the coating layer will be too thick, which is not conducive to the transmission efficiency of ions in the cathode active material; if the content of the fast ion conductor is too low, lithium ions cannot be effectively transported.
在一些实施方式中，所述金属化合物导电剂选自碳化钛、氮化钛和硼化钛中的一种或多种；可选地，所述金属化合物导电剂的量为0.5-10重量％、可选为1-6重量％，基于所述正极活性材料的重量计。通过选择上述金属化合物导电剂且使其含量满足上述范围，可以进一步改善正极活性材料的倍率性能和循环性能。若金属化合物导电剂的含量过高，会导致包覆层过厚而不利于正极活性材料中离子的传输效率；若金属化合物导电剂的含量过低，则无法对电子进行有效输送。In some embodiments, the metal compound conductive agent is selected from one or more of titanium carbide, titanium nitride and titanium boride; optionally, the amount of the metal compound conductive agent is 0.5-10% by weight. , optionally 1-6% by weight, based on the weight of the cathode active material. By selecting the above metal compound conductive agent and making the content satisfy the above range, the rate performance and cycle performance of the cathode active material can be further improved. If the content of the metal compound conductive agent is too high, the coating layer will be too thick, which is detrimental to the transmission efficiency of ions in the cathode active material; if the content of the metal compound conductive agent is too low, electrons cannot be effectively transported.
在一些实施方式中，所述正极活性材料中的所述快离子导体与所述金属化合物导电剂的重量比为1.3-3:1，可选为1.7-2.7:1。通过控制正极活性材料的包覆层中的快离子导体与金属化合物导电剂的重量比，可以使 正极活性材料兼具高的离子电导率和电子电导率，从而进一步改善正极活性材料的循环性能和倍率性能。In some embodiments, the weight ratio of the fast ion conductor to the metal compound conductive agent in the cathode active material is 1.3-3:1, optionally 1.7-2.7:1. By controlling the weight ratio of the fast ion conductor to the metal compound conductive agent in the coating layer of the cathode active material, the cathode active material can have both high ionic conductivity and electronic conductivity, thereby further improving the cycle performance and performance of the cathode active material. magnification performance.
在一些实施方式中，所述富锂锰基基体材料的化学式为xLi 2MnO 3·(1-x)LiMO 2，其中所述M为选自Fe、Al、Co、Mn、Ni、Cr、Ti、Mo、Nb、Zr、Sn、V、Mg、Cu、Zn、B、Na、Ca和Ru中的一种或多种的组合，可选地，所述M为选自Co、Ni、Cr、V、Mo、Mn、Al、Nb和Ti中的一种或多种的组合，且0＜x＜1。 In some embodiments, the chemical formula of the lithium-rich manganese-based matrix material is xLi 2 MnO 3 ·(1-x)LiMO 2 , wherein M is selected from Fe, Al, Co, Mn, Ni, Cr, Ti , Mo, Nb, Zr, Sn, V, Mg, Cu, Zn, B, Na, Ca and Ru in one or more combinations, optionally, the M is selected from Co, Ni, Cr, One or a combination of one or more of V, Mo, Mn, Al, Nb and Ti, and 0<x<1.
在一些实施方式中，所述正极活性材料的Dv50为5-20μm、可选为7-13μm，所述一次颗粒的Dv50为0.05-1μm、可选为0.1-0.4μm。当所述正极活性材料的粒径在上述范围内时，能够使得所述正极活性材料的压实密度最优化，从而进一步改善正极活性材料的性能。In some embodiments, the Dv50 of the positive active material is 5-20 μm, optionally 7-13 μm, and the Dv50 of the primary particles is 0.05-1 μm, optionally 0.1-0.4 μm. When the particle size of the positive active material is within the above range, the compacted density of the positive active material can be optimized, thereby further improving the performance of the positive active material.
在一些实施方式中，所述正极活性材料在5吨力下的压实密度为2.4-3.4g/cm 3，可选为2.7-3.2g/cm 3。压实密度越高，单位体积活性材料的重量越大，因此提高压实密度有利于提高电芯的体积能量密度。所述正极活性材料具有高的压实密度高，颗粒间填充度高，不仅有利于进一步提高该正极活性材料的加工性能。压实密度可依据GB/T 24533-2009测量。 In some embodiments, the compacted density of the cathode active material under 5 tons of force is 2.4-3.4g/cm 3 , optionally 2.7-3.2g/cm 3 . The higher the compaction density, the greater the weight of the active material per unit volume. Therefore, increasing the compaction density is beneficial to increasing the volumetric energy density of the battery core. The positive active material has a high compaction density and a high filling degree between particles, which is not only conducive to further improving the processing performance of the positive active material. The compacted density can be measured according to GB/T 24533-2009.
在一些实施方式中，所述包覆层的厚度为0.005-0.2μm、可选为0.01-0.1μm，更可选为0.04-0.08μm。包覆层的厚度满足上述范围时，可以使正极活性材料具有改善的循环性能和倍率性能。若包覆层的厚度过厚，则不利于电子和离子的传输效率；若包覆层的厚度过薄，则无法有效的传输电子和离子。In some embodiments, the thickness of the coating layer is 0.005-0.2 μm, optionally 0.01-0.1 μm, and more optionally 0.04-0.08 μm. When the thickness of the coating layer meets the above range, the cathode active material can have improved cycle performance and rate performance. If the thickness of the coating layer is too thick, it will be detrimental to the transmission efficiency of electrons and ions; if the thickness of the coating layer is too thin, it will not be able to effectively transmit electrons and ions.
在一些实施方式中，所述正极活性材料中的所述快离子导体的重量a与所述金属化合物导电剂的重量b满足以下：2≤a*b/(a+b)≤4，可选地，2.5≤a*b/(a+b)≤3。通过控制正极活性材料的包覆层中的快离子导体与金属化合物导电剂满足上述关系式，可以使正极活性材料兼具高的离子电导率和电子电导率，从而进一步改善正极活性材料的循环性能和倍率性能。In some embodiments, the weight a of the fast ion conductor in the positive active material and the weight b of the metal compound conductive agent satisfy the following: 2≤a*b/(a+b)≤4, optional Ground, 2.5≤a*b/(a+b)≤3. By controlling the fast ion conductor and metal compound conductive agent in the coating layer of the cathode active material to satisfy the above relationship, the cathode active material can have both high ionic conductivity and electronic conductivity, thereby further improving the cycle performance of the cathode active material. and rate performance.
本申请的第二方面提供一种正极活性材料的制备方法，所述方法包括以下步骤：A second aspect of the application provides a method for preparing a cathode active material, which method includes the following steps:
S1)将富锂锰基正极活性材料前驱体在惰性气氛中破碎，得到富锂锰基正极活性材料前驱体的一次颗粒；S1) Crush the lithium-rich manganese-based cathode active material precursor in an inert atmosphere to obtain primary particles of the lithium-rich manganese-based cathode active material precursor;
S2)将快离子导体前驱体、金属化合物导电剂和分散剂聚乙烯吡咯烷酮加入水中并混合均匀，再向其中加入步骤S1)的富锂锰基正极活性材料前驱体的一次颗粒，混合均匀，得到固体混合物的悬浊液；S2) Add the fast ion conductor precursor, metal compound conductive agent and dispersant polyvinylpyrrolidone into water and mix evenly, then add the primary particles of the lithium-rich manganese-based cathode active material precursor of step S1) into the water and mix evenly to obtain Suspensions of solid mixtures;
S3)将步骤S2)的固体混合物的悬浊液经喷雾干燥二次造粒，得到正极活性材料前驱体粉末；S3) spray-dry the suspension of the solid mixture in step S2) for secondary granulation to obtain positive electrode active material precursor powder;
S4)将步骤S3)的正极活性材料前驱体粉末与锂源混合均匀，经烧结，得到正极活性材料，S4) Mix the cathode active material precursor powder and the lithium source in step S3) evenly, and sinter them to obtain the cathode active material,
所述正极活性材料为由一次颗粒堆叠形成的二次颗粒，其中所述一次颗粒包括富锂锰基基体材料和位于所述富锂锰基基体材料表面的包覆层，所述包覆层包括快离子导体和金属化合物导电剂。The positive active material is a secondary particle formed by stacking primary particles, wherein the primary particle includes a lithium-rich manganese-based matrix material and a coating layer located on the surface of the lithium-rich manganese-based matrix material, and the coating layer includes Fast ion conductor and metal compound conductive agent.
通过上述方法，一方面在所述一次颗粒的基体材料外表面构建一种均质复合包覆层，有效提升正极活性材料的离子传输能力和电子传输能力，从而获得具有改善的倍率性能的正极活性材料；另一方面可以显著提升包覆层与基体材料的结合强度，避免在循环过程中应力不均匀导致的包覆层脱落而造成电池性能劣化，有效改善了正极活性材料的循环性能。Through the above method, on the one hand, a homogeneous composite coating layer is constructed on the outer surface of the matrix material of the primary particles, which effectively improves the ion transmission capacity and electron transmission capacity of the positive electrode active material, thereby obtaining a positive electrode active material with improved rate performance. material; on the other hand, it can significantly improve the bonding strength between the coating layer and the base material, avoid the degradation of battery performance caused by the shedding of the coating layer caused by uneven stress during the cycle, and effectively improve the cycle performance of the cathode active material.
在一些实施方式中，在所述步骤S1)中，所述富锂锰基正极活性材料前驱体的一次颗粒的Dv50为0.05-1.1μm、可选为0.1-0.4μm。通过控制前驱体的一次颗粒的粒径，有利于获得具有改善的倍率性能和循环性能的正极活性材料。In some embodiments, in step S1), the Dv50 of the primary particles of the lithium-rich manganese-based cathode active material precursor is 0.05-1.1 μm, optionally 0.1-0.4 μm. By controlling the particle size of the primary particles of the precursor, it is beneficial to obtain a cathode active material with improved rate performance and cycle performance.
在本申请中，所述破碎方法包括磨砂、气流粉碎、机械磨粉碎和高能球磨中的一种或多种，可选地，所述破碎方法为高能球磨。In this application, the crushing method includes one or more of grinding, jet crushing, mechanical mill crushing and high-energy ball milling. Alternatively, the crushing method is high-energy ball milling.
在一些实施方式中，在所述步骤S2)中，所述固体混合物包含快离子导体前驱体、金属化合物导电剂和富锂锰基正极活性材料前驱体的一次颗粒，其中，所述快离子导体前驱体选自二氧化硅、磷酸锂、硼酸锂、五氧化二铌、氧化铝、二氧化锆和磷酸二氢锂中的一种或多种，可选地，所述快离子导体前驱体选自二氧化硅、磷酸锂、硼酸锂中的一种或多种；可选地，所述快离子导体的量为0.4-16重量％、可选为1.5-9.5重量％，基于所述固体混合物的重量计，且所述金属化合物导电剂选自碳化钛、氮化钛和硼化钛中的一种或多种；可选地，所述金属化合物导电剂的量为0.4-8重量％、可选为0.8-5重量％，基于所述固体混合物的重量计。通过选择上述的快离子导体前驱体和金属化合物导电剂，并使它们的含 量满足上述范围，有利于获得具有改善的倍率性能和循环性能的正极活性材料。In some embodiments, in step S2), the solid mixture includes primary particles of a fast ion conductor precursor, a metal compound conductive agent, and a lithium-rich manganese-based cathode active material precursor, wherein the fast ion conductor The precursor is selected from one or more of silicon dioxide, lithium phosphate, lithium borate, niobium pentoxide, alumina, zirconium dioxide and lithium dihydrogen phosphate. Optionally, the fast ion conductor precursor is selected from One or more of silica, lithium phosphate, and lithium borate; optionally, the amount of the fast ion conductor is 0.4-16% by weight, optionally 1.5-9.5% by weight, based on the solid mixture by weight, and the metal compound conductive agent is selected from one or more of titanium carbide, titanium nitride and titanium boride; optionally, the amount of the metal compound conductive agent is 0.4-8% by weight, Optional is 0.8-5% by weight, based on the weight of the solid mixture. By selecting the above-mentioned fast ion conductor precursor and metal compound conductive agent and making their contents meet the above range, it is beneficial to obtain a cathode active material with improved rate performance and cycle performance.
在一些实施方式中，在所述步骤S4)中，所述烧结的气氛为氧气、空气或压缩空气，烧结温度为700-1000℃，例如可以是700℃、800℃、900℃或1000℃等，但不限于所列点值，只要是在上述范围内的数值同样适用，烧结时间为5-10h，例如可以是5h、6h、7h、8h、9h或10h，但不限于所列点值，只要是在上述范围内的数值同样适用。通过控制烧结温度和烧结时间，能够使烧结后材料的结晶度更高，有利于获得具有改善的倍率性能和循环性能的正极活性材料。In some embodiments, in step S4), the sintering atmosphere is oxygen, air or compressed air, and the sintering temperature is 700-1000°C, for example, it can be 700°C, 800°C, 900°C or 1000°C, etc. , but are not limited to the listed point values. As long as the values are within the above range, the same applies. The sintering time is 5-10h. For example, it can be 5h, 6h, 7h, 8h, 9h or 10h, but is not limited to the listed point values. The same applies as long as the values are within the above range. By controlling the sintering temperature and sintering time, the crystallinity of the sintering material can be higher, which is beneficial to obtaining cathode active materials with improved rate performance and cycle performance.
本申请的第三方面提供一种正极极片，所述正极极片包括正极集流体以及设置在正极集流体至少一个表面的正极膜层，所述正极膜层包括本申请第一方面的正极活性材料或通过本申请第二方面的方法制备的正极活性材料，并且所述正极活性材料在所述正极膜层中的含量为10重量％以上，基于所述正极膜层的总重量计。A third aspect of the present application provides a positive electrode sheet. 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 film layer includes the positive electrode activity of the first aspect of the application. material or a cathode active material prepared by the method of the second aspect of the present application, and the content of the cathode active material in the cathode film layer is more than 10% by weight, based on the total weight of the cathode film layer.
本申请的第四方面提供一种二次电池，其包括本申请第一方面的正极活性材料或根据本申请第二方面的方法制备的正极活性材料。A fourth aspect of the application provides a secondary battery, which includes the cathode active material of the first aspect of the application or the cathode active material prepared according to the method of the second aspect of the application.
本申请的第五方面提供一种电池模块，其包括本申请的第四方面的二次电池。A fifth aspect of the present application provides a battery module including the secondary battery of the fourth aspect of the present application.
本申请的第六方面提供一种电池包，其包括本申请的第五方面的电池模块。A sixth aspect of the present application provides a battery pack, which includes the battery module of the fifth aspect of the present application.
本申请的第七方面提供一种用电装置，其包括选自本申请的第四方面的二次电池、本申请的第五方面的电池模块或本申请的第六方面的电池包中的至少一种。A seventh aspect of the present application provides an electrical device, which includes at least one selected from the group consisting of the secondary battery of the fourth aspect of the present application, the battery module of the fifth aspect of the present application, or the battery pack of the sixth aspect of the present application. A sort of.
另外，以下适当参照附图对本申请的二次电池、电池模块、电池包和用电装置进行说明。In addition, the secondary battery, battery module, battery pack and electric device of the present application will be described below with appropriate reference to the drawings.
本申请的一个实施方式中，提供一种二次电池。In one embodiment of the present application, a secondary battery is provided.
通常情况下，二次电池包括正极极片、负极极片、电解质和隔离膜。在电池充放电过程中，活性离子在正极极片和负极极片之间往返嵌入和脱出。电解质在正极极片和负极极片之间起到传导离子的作用。隔离膜设置在正极极片和负极极片之间，主要起到防止正负极短路的 作用，同时可以使离子通过。Typically, a secondary battery includes a positive electrode plate, a negative electrode plate, an electrolyte and a separator. During the charging and discharging process of the battery, active ions are inserted and detached back and forth between the positive and negative electrodes. The electrolyte plays a role in conducting ions between the positive and negative electrodes. The isolation film is placed between the positive electrode piece and the negative electrode piece. It mainly prevents the positive and negative electrodes from short-circuiting and allows ions to pass through.
[正极极片][Positive pole piece]
正极极片包括正极集流体以及设置在正极集流体至少一个表面的正极膜层，所述正极膜层包括本申请第一方面的正极活性材料。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 film layer includes the positive electrode active material of the first aspect of the present application.
作为示例，正极集流体具有在其自身厚度方向相对的两个表面，正极膜层设置在正极集流体相对的两个表面的其中任意一者或两者上。As an example, the positive electrode current collector has two surfaces facing each other in its own 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.
在一些实施方式中，所述正极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可采用铝箔。复合集流体可包括高分子材料基层和形成于高分子材料基层至少一个表面上的金属层。复合集流体可通过将金属材料(铝、铝合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum foil can 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 base layer. The composite current collector can be formed by forming metal materials (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on polymer material substrates (such as polypropylene (PP), polyterephthalate It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
在一些实施方式中，除了本申请第一方面的正极活性材料之外，正极活性材料还可采用本领域公知的用于电池的正极活性材料。作为示例，正极活性材料可包括以下材料中的至少一种：橄榄石结构的含锂磷酸盐、锂过渡金属氧化物及其各自的改性化合物。但本申请并不限定于这些材料，还可以使用其他可被用作电池正极活性材料的传统材料。这些正极活性材料可以仅单独使用一种，也可以将两种以上组合使用，其中本申请第一方面的正极活性材料为85-100％，其他正极活性材料为0-15％。其中，锂过渡金属氧化物的示例可包括但不限于锂钴氧化物(如LiCoO 2)、锂镍氧化物(如LiNiO 2)、锂锰氧化物(如LiMnO 2、LiMn 2O 4)、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物(如LiNi 1/3Co 1/3Mn 1/3O 2(也可以简称为NCM 333)、LiNi 0.5Co 0.2Mn 0.3O 2(也可以简称为NCM 523)、LiNi 0.5Co 0.25Mn 0.25O 2(也可以简称为NCM 211)、LiNi 0.6Co 0.2Mn 0.2O 2(也可以简称为NCM 622)、LiNi 0.8Co 0.1Mn 0.1O 2(也可以简称为NCM 811)、锂镍钴铝氧化物(如LiNi 0.85Co 0.15Al 0.05O 2)及其改性化合物等中的至少一种。橄榄石结构的含锂磷酸盐的示例可包括但不限于磷酸铁锂(如LiFePO 4(也可以简称为LFP))、磷酸铁锂与碳的复 合材料、磷酸锰锂(如LiMnPO 4)、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料中的至少一种。所述正极活性材料在正极膜层中的重量比为80-100重量％，基于正极膜层的总重量计。 In some embodiments, in addition to the cathode active material of the first aspect of the present application, the cathode active material may also be a cathode active material known in the art for use in batteries. As an example, the cathode active material may include at least one of the following materials: an olivine-structured lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials of batteries can also be used. These cathode active materials may be used alone or in combination of two or more, wherein the cathode active material of the first aspect of the application accounts for 85-100% and the other cathode active materials account for 0-15%. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO 2 ), lithium nickel oxides (such as LiNiO 2 ), lithium manganese oxides (such as LiMnO 2 , LiMn 2 O 4 ), lithium Nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (can also be abbreviated to NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (can also be abbreviated to NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (can also be abbreviated to NCM 622 ), LiNi At least one of 0.8 Co 0.1 Mn 0.1 O 2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O 2 ) and its modified compounds. The olivine structure contains Examples of lithium phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also referred to as LFP)), composites of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), lithium manganese phosphate and carbon. At least one of composite materials, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon. The weight ratio of the positive electrode active material in the positive electrode film layer is 80-100% by weight, based on the total weight of the positive electrode film layer count.
在一些实施方式中，正极膜层还可选地包括粘结剂。作为示例，所述粘结剂可以包括聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物及含氟丙烯酸酯树脂中的至少一种。所述粘结剂在正极膜层中的重量比为0-20重量％，基于正极膜层的总重量计。In some embodiments, the positive electrode film layer optionally further includes a binder. As examples, the binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene At least one of ethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin. The weight ratio of the binder in the positive electrode film layer is 0-20% by weight, based on the total weight of the positive electrode film layer.
在一些实施方式中，正极膜层还可选地包括导电剂。作为示例，所述导电剂可以包括超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。所述导电剂在正极膜层中的重量比为0-20重量％，基于正极膜层的总重量计。In some embodiments, the positive electrode film layer optionally further includes a conductive agent. As an example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers. The weight ratio of the conductive agent in the positive electrode film layer is 0-20% by weight, based on the total weight of the positive electrode film layer.
在一些实施方式中，可以通过以下方式制备正极极片：将上述用于制备正极极片的组分，例如正极活性材料、导电剂、粘结剂和任意其他的组分分散于溶剂(例如N-甲基吡咯烷酮)中，形成正极浆料；其中所述正极浆料固含量为40-80wt％，室温下的粘度调整到5000-25000mPa·s，将正极浆料涂覆在正极集流体上，经烘干、冷压等工序后，即可得到正极极片，正极粉末涂布单位面密度为150-350mg/m 2，正极极片压实密度为3.0-3.6g/cm 3，可选为3.3-3.5g/cm 3。所述压实密度的计算公式为 In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components in a solvent (such as N -methylpyrrolidone), forming a positive electrode slurry; wherein the solid content of the positive electrode slurry is 40-80wt%, the viscosity at room temperature is adjusted to 5000-25000mPa·s, and the positive electrode slurry is coated on the positive electrode current collector, After drying, cold pressing and other processes, the positive electrode piece can be obtained. The unit area density of the positive electrode powder coating is 150-350mg/m 2 and the compacted density of the positive electrode piece is 3.0-3.6g/cm 3. The optional 3.3-3.5g/cm 3 . The calculation formula of the compacted density is
压实密度＝涂布面密度/(挤压后极片厚度-集流体厚度)。Compaction density = coating surface density / (thickness of electrode piece after extrusion - thickness of current collector).
[负极极片][Negative pole piece]
负极极片包括负极集流体以及设置在负极集流体至少一个表面上的负极膜层，所述负极膜层包括负极活性材料。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.
作为示例，负极集流体具有在其自身厚度方向相对的两个表面，负极膜层设置在负极集流体相对的两个表面中的任意一者或两者上。As an example, 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.
在一些实施方式中，所述负极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可以采用铜箔。复合集流体可包括高分子材料基层和形成于高分子材料基材至少一个表面上的金属层。复合集流体可通过将金属材料(铜、铜合金、镍、镍合金、钛、钛合金、银 及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, copper foil can 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 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.).
在一些实施方式中，负极活性材料可采用本领域公知的用于电池的负极活性材料。作为示例，负极活性材料可包括以下材料中的至少一种：人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂等。所述硅基材料可选自单质硅、硅氧化合物、硅碳复合物、硅氮复合物以及硅合金中的至少一种。所述锡基材料可选自单质锡、锡氧化合物以及锡合金中的至少一种。但本申请并不限定于这些材料，还可以使用其他可被用作电池负极活性材料的传统材料。这些负极活性材料可以仅单独使用一种，也可以将两种以上组合使用。所述负极极活性材料可以具有1μm-15μm、优选4μm-9μm的平均粒径(D 10)，具有12μm-22μm、优选14μm-17μm的平均粒径(D 50)，并且具有26μm至40μm、优选30μm-37μm的平均粒径(D 90)。D 10为样品的体积累计分布百分数达到10％时对应的粒径；D 50为样品的体积累计分布百分数达到50％时对应的粒径；D 90为样品的体积累计分布百分数达到90％时对应的粒径。所述负极活性材料在负极膜层中的重量比为70-100重量％，基于负极膜层的总重量计。 In some embodiments, the negative active material may be a negative active material known in the art for batteries. As an example, 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. However, 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 active material may have an average particle diameter (D 10 ) of 1 μm to 15 μm, preferably 4 μm to 9 μm, an average particle diameter (D 50 ) of 12 μm to 22 μm, preferably 14 μm to 17 μm, and 26 μm to 40 μm, preferably Average particle size (D 90 ) of 30 μm-37 μm. D 10 is the particle size corresponding to when the cumulative volume distribution percentage of the sample reaches 10%; D 50 is the particle size corresponding to when the cumulative volume distribution percentage of the sample reaches 50%; D 90 is the corresponding particle size when the cumulative volume distribution percentage of the sample reaches 90%. particle size. The weight ratio of the negative active material in the negative electrode film layer is 70-100% by weight, based on the total weight of the negative electrode film layer.
在一些实施方式中，负极膜层还可选地包括粘结剂。所述粘结剂可选自丁苯橡胶(SBR)、聚丙烯酸(PAA)、聚丙烯酸钠(PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)、聚甲基丙烯酸(PMAA)及羧甲基壳聚糖(CMCS)中的至少一种。所述粘结剂在负极膜层中的重量比为0-30重量％，基于负极膜层的总重量计。In some embodiments, the negative electrode film layer optionally further includes a binder. The binder can be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), polysodium acrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), poly At least one of methacrylic acid (PMAA) and carboxymethyl chitosan (CMCS). The weight ratio of the binder in the negative electrode film layer is 0-30% by weight, based on the total weight of the negative electrode film layer.
在一些实施方式中，负极膜层还可选地包括导电剂。导电剂可选自超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。所述导电剂在负极膜层中的重量比为0-20重量％，基于负极膜层的总重量计。In some embodiments, 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 weight ratio of the conductive agent in the negative electrode film layer is 0-20% by weight, based on the total weight of the negative electrode film layer.
在一些实施方式中，负极膜层还可选地包括其他助剂，例如增稠剂(如羧甲基纤维素钠(CMC-Na))等。所述其他助剂在负极膜层中的重量比为0-15重量％，基于负极膜层的总重量计。In some embodiments, the negative electrode film layer optionally includes other auxiliaries, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like. The weight ratio of the other additives in the negative electrode film layer is 0-15% by weight, based on the total weight of the negative electrode film layer.
在一些实施方式中，可以通过以下方式制备负极极片：将上述用 于制备负极极片的组分，例如负极活性材料、导电剂、粘结剂和任意其他组分分散于溶剂(例如去离子水)中，形成负极浆料，其中所述负极浆料固含量为30-70wt％，室温下的粘度调整到2000-10000mPa·s；将负极浆料涂覆在负极集流体上，经烘干、冷压等工序后，即可得到负极极片。负极粉末涂布单位面密度为75-220mg/m 2，负极极片压实密度1.2-2.0g/m 3。 In some embodiments, 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, wherein the solid content of the negative electrode slurry is 30-70wt%, and the viscosity at room temperature is adjusted to 2000-10000mPa·s; the negative electrode slurry is coated on the negative electrode current collector and dried , cold pressing and other processes, the negative electrode piece can be obtained. The negative electrode powder coating unit area density is 75-220mg/m 2 , and the negative electrode plate compacted density is 1.2-2.0g/m 3 .
[电解质][electrolyte]
电解质在正极极片和负极极片之间起到传导离子的作用。本申请对电解质的种类没有具体的限制，可根据需求进行选择。例如，电解质可以是液态的、凝胶态的或全固态的。The electrolyte plays a role in conducting ions between the positive and negative electrodes. There is no specific restriction on the type of electrolyte in this application, and it can be selected according to needs. For example, the electrolyte can be liquid, gel, or completely solid.
在一些实施方式中，所述电解质采用电解液。所述电解液包括电解质盐和溶剂。In some embodiments, the electrolyte is an electrolyte solution. The electrolyte solution includes electrolyte salts and solvents.
在一些实施方式中，电解质盐可选自六氟磷酸锂、四氟硼酸锂、高氯酸锂、六氟砷酸锂、双氟磺酰亚胺锂、双三氟甲磺酰亚胺锂、三氟甲磺酸锂、二氟磷酸锂、二氟草酸硼酸锂、二草酸硼酸锂、二氟二草酸磷酸锂及四氟草酸磷酸锂中的至少一种。所述电解质盐的浓度通常为0.5-5mol/L。In some embodiments, the electrolyte salt may be selected from the group consisting of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonimide, lithium bistrifluoromethanesulfonimide, trifluoromethane At least one of lithium sulfonate, lithium difluorophosphate, lithium difluoroborate, lithium dioxaloborate, lithium difluorodioxalate phosphate and lithium tetrafluoroxalate phosphate. The concentration of the electrolyte salt is usually 0.5-5mol/L.
在一些实施方式中，溶剂可选自碳酸亚乙酯、碳酸亚丙酯、碳酸甲乙酯、碳酸二乙酯、碳酸二甲酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸亚丁酯、氟代碳酸亚乙酯、甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丁酸甲酯、丁酸乙酯、1,4-丁内酯、环丁砜、二甲砜、甲乙砜及二乙砜中的至少一种。In some embodiments, the solvent may be selected from the group consisting of ethylene carbonate, propylene carbonate, methylethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, Butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate At least one of ester, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
在一些实施方式中，所述电解液还可选地包括添加剂。例如添加剂可以包括负极成膜添加剂、正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温或低温性能的添加剂等。In some embodiments, the electrolyte optionally further includes additives. For example, 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.
[隔离膜][Isolation film]
在一些实施方式中，二次电池中还包括隔离膜。本申请对隔离膜的种类没有特别的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构隔离膜。In some embodiments, the secondary battery further includes 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.
在一些实施方式中，隔离膜的材质可选自玻璃纤维、无纺布、聚 乙烯、聚丙烯及聚偏二氟乙烯中的至少一种。隔离膜可以是单层薄膜，也可以是多层复合薄膜，没有特别限制。在隔离膜为多层复合薄膜时，各层的材料可以相同或不同，没有特别限制。In some embodiments, 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.
在一些实施方式中，所述隔离膜的厚度为6-40μm，可选为12-20μm。In some embodiments, the thickness of the isolation film is 6-40 μm, optionally 12-20 μm.
在一些实施方式中，正极极片、负极极片和隔离膜可通过卷绕工艺或叠片工艺制成电极组件。In some embodiments, 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.
在一些实施方式中，二次电池可包括外包装。该外包装可用于封装上述电极组件及电解质。In some embodiments, the secondary battery may include an outer packaging. The outer packaging can be used to package the above-mentioned electrode assembly and electrolyte.
在一些实施方式中，二次电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。二次电池的外包装也可以是软包，例如袋式软包。软包的材质可以是塑料，作为塑料，可列举出聚丙烯、聚对苯二甲酸丁二醇酯以及聚丁二酸丁二醇酯等。In some embodiments, the outer packaging of the secondary battery 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 bag, such as a bag-type soft bag. The material of the soft bag may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.
本申请对二次电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。例如，图1是作为一个示例的方形结构的二次电池5。This application has no particular limitation on the shape of the secondary battery, which can be cylindrical, square or any other shape. For example, FIG. 1 shows a square-structured secondary battery 5 as an example.
在一些实施方式中，参照图2，外包装可包括壳体51和盖板53。其中，壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53能够盖设于所述开口，以封闭所述容纳腔。正极极片、负极极片和隔离膜可经卷绕工艺或叠片工艺形成电极组件52。电极组件52封装于所述容纳腔内。电解液浸润于电极组件52中。二次电池5所含电极组件52的数量可以为一个或多个，本领域技术人员可根据具体实际需求进行选择。In some embodiments, referring to FIG. 2 , 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 can 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 those skilled in the art can select according to specific actual needs.
在一些实施方式中，二次电池可以组装成电池模块，电池模块所含二次电池的数量可以为一个或多个，具体数量本领域技术人员可根据电池模块的应用和容量进行选择。In some embodiments, secondary batteries can be assembled into battery modules, and the number of secondary batteries contained in the battery module can be one or more. Those skilled in the art can select the specific number according to the application and capacity of the battery module.
图3是作为一个示例的电池模块4。参照图3，在电池模块4中，多个二次电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个二次电池5进行固定。Figure 3 is a battery module 4 as an example. Referring to FIG. 3 , in the battery module 4 , a plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4 . Of course, it can also be arranged in any other way. Furthermore, the plurality of secondary batteries 5 can be fixed by fasteners.
可选地，电池模块4还可以包括具有容纳空间的外壳，多个二次电池5容纳于该容纳空间。Optionally, the battery module 4 may further include a housing having a receiving space in which a plurality of secondary batteries 5 are received.
在一些实施方式中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以为一个或多个，具体数量本领域技术人员可根据电池包的应用和容量进行选择。In some embodiments, the above-mentioned battery modules can also be assembled into a battery pack. The number of battery modules contained in the battery pack can be one or more. Those skilled in the art can select the specific number according to the application and capacity of the battery pack.
图4和图5是作为一个示例的电池包1。参照图4和图5，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。Figures 4 and 5 show the battery pack 1 as an example. Referring to FIGS. 4 and 5 , 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 2 and a lower box 3 . The upper box 2 can be covered with 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.
另外，本申请还提供一种用电装置，所述用电装置包括本申请提供的二次电池、电池模块、或电池包中的至少一种。所述二次电池、电池模块、或电池包可以用作所述用电装置的电源，也可以用作所述用电装置的能量存储单元。所述用电装置可以包括移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能***等，但不限于此。In addition, the present application also provides an electrical device, which includes at least one of the secondary battery, battery module, or battery pack provided by the present application. The secondary battery, battery module, or battery pack may be used as a power source for the electrical device, or may be used as an energy storage unit for the electrical 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, and electric golf carts). , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited to these.
作为所述用电装置，可以根据其使用需求来选择二次电池、电池模块或电池包。As the power-consuming device, a secondary battery, a battery module or a battery pack can be selected according to its usage requirements.
图6是作为一个示例的用电装置。该用电装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该用电装置对二次电池的高功率和高能量密度的需求，可以采用电池包或电池模块。Figure 6 is an electrical device as an example. The electric device is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, etc. In order to meet the high power and high energy density requirements of the secondary battery for the electrical device, a battery pack or battery module can be used.
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用二次电池作为电源。As another example, the device may be a mobile phone, a tablet, a laptop, etc. The device is usually required to be thin and light, and a secondary battery can be used as a power source.
实施例Example
以下，说明本申请的实施例。下面描述的实施例是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试剂或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。Hereinafter, examples of the present application will be described. The embodiments described below are illustrative and are only used to explain the present application and are not to be construed as limitations of the present application. If specific techniques or conditions are not specified in the examples, the techniques or conditions described in literature in the field or product instructions will be followed. If the manufacturer of the reagents or instruments used is not indicated, they are all conventional products that can be purchased commercially.
一、二次电池的制备1. Preparation of secondary batteries
实施例1Example 1
(1)富锂锰基正极活性材料前驱体的制备(1) Preparation of lithium-rich manganese-based cathode active material precursor
使用硫酸锰作为锰源且硫酸镍作为镍源，按照Mn、Ni元素的摩尔比为7:3配制过渡金属盐溶液，该溶液的浓度为2mol/L。配制浓度为2mol/L的碳酸钠溶液，配制浓度为1mol/L的氨水溶液。在反应釜中加入釜体积20％的去离子水作为反应底液，在氮气氛围保护下，分别以v1＝35ml/h、v2＝5-50ml/h、v3＝35ml/h的流速将过渡金属盐溶液、碳酸钠溶液和氨水溶液同时泵入反应釜内，并通过调节碳酸钠溶液的进料流速v2来控制反应体系的pH＝9.5，在维持反应体系温度50℃、搅拌速度800rpm/min条件下反应20h。进料结束后对反应浆料继续陈化10h，然后将沉淀物进行过滤、洗涤和烘干，得到富锂锰基正极活性材料前驱体Ni 0.3Mn 0.7CO 3。 Using manganese sulfate as the manganese source and nickel sulfate as the nickel source, a transition metal salt solution is prepared according to a molar ratio of Mn and Ni elements of 7:3. The concentration of the solution is 2 mol/L. Prepare a sodium carbonate solution with a concentration of 2 mol/L and an ammonia solution with a concentration of 1 mol/L. Add 20% of the kettle volume of deionized water as the reaction bottom liquid into the reaction kettle. Under the protection of nitrogen atmosphere, transfer the transition metal into the reaction kettle at flow rates of v1=35ml/h, v2=5-50ml/h, and v3=35ml/h. Salt solution, sodium carbonate solution and ammonia solution are pumped into the reaction kettle at the same time, and the pH of the reaction system is controlled by adjusting the feed flow rate v2 of the sodium carbonate solution to 9.5. The temperature of the reaction system is maintained at 50°C and the stirring speed is 800 rpm/min. React for 20h. After the feeding is completed, the reaction slurry is aged for 10 hours, and then the precipitate is filtered, washed and dried to obtain the lithium-rich manganese-based cathode active material precursor Ni 0.3 Mn 0.7 CO 3 .
(2)正极活性材料的制备(2) Preparation of positive active materials
将上述制得的富锂锰基正极活性材料前驱体Ni 0.3Mn 0.7CO 3(Dv50为8μm)在氮气气氛中通过高能球磨进行破碎，得到富锂锰基正极活性材料前驱体的一次颗粒(Dv50为0.3μm)。将快离子导体前驱体硼酸锂、金属化合物导电剂硼化钛和分散剂聚乙烯吡咯烷酮加入水中并在800rpm/min下搅拌混合均匀，再向其中加入富锂锰基正极活性材料前驱体的一次颗粒，在500rpm/min下搅拌混合均匀，得到固体混合物的悬浊液，在该固体混合物中硼酸锂、硼化钛和富锂锰基正极活性材料前驱体的重量比为6.1:3.1:90.8。随后将上述固体混合物的悬浊液经喷雾干燥二次造粒(厂家：步琦；型号：B-290)，喷雾干燥的进风口温度为250℃、喷嘴口径为600μm，得到正极活性材料前驱体粉末。最后将上述正极活性材料前驱体粉末与锂源碳酸锂以重量比为100:50混合均匀，在空气气氛下在800℃下烧结8h，得到正极活性材料。 The lithium-rich manganese-based cathode active material precursor Ni 0.3 Mn 0.7 CO 3 (Dv50 is 8 μm) prepared above was crushed by high-energy ball milling in a nitrogen atmosphere to obtain primary particles (Dv50) of the lithium-rich manganese-based cathode active material precursor. is 0.3μm). Add the fast ion conductor precursor lithium borate, the metal compound conductive agent titanium boride and the dispersant polyvinylpyrrolidone to the water and stir at 800 rpm/min to mix evenly, and then add primary particles of the lithium-rich manganese-based cathode active material precursor to the water. , stir and mix evenly at 500 rpm/min to obtain a suspension of a solid mixture. The weight ratio of lithium borate, titanium boride and lithium-rich manganese-based cathode active material precursor in the solid mixture is 6.1:3.1:90.8. The suspension of the above solid mixture was then spray-dried and granulated twice (manufacturer: Buqi; model: B-290). The air inlet temperature of the spray drying was 250°C and the nozzle diameter was 600 μm to obtain the positive electrode active material precursor. powder. Finally, the above-mentioned positive electrode active material precursor powder and lithium source lithium carbonate were evenly mixed at a weight ratio of 100:50, and then sintered at 800°C for 8 hours in an air atmosphere to obtain the positive electrode active material.
(3)全电池的制备(3) Preparation of full battery
【正极极片】将上述正极活性材料、导电剂乙炔黑、粘结剂聚偏二氟乙烯(PVDF)按重量比92:2.5:5.5在N-甲基吡咯烷酮溶剂体系中混合均 匀后，涂覆于铝箔上并烘干、冷压，得到正极极片。涂覆量为0.4g/cm 2，压实密度为2.4g/cm 3。 [Positive electrode sheet] Mix the above positive active material, conductive agent acetylene black, and binder polyvinylidene fluoride (PVDF) in the N-methylpyrrolidone solvent system in a weight ratio of 92:2.5:5.5, and then coat Put it on aluminum foil, dry it, and cold-press it to obtain the positive electrode piece. The coating amount is 0.4g/cm 2 and the compacted density is 2.4g/cm 3 .
【负极极片】将负极活性材料人造石墨、导电剂碳黑、粘结剂丁苯橡胶(SBR)按重量比92:2:6在去离子水中混合均匀后，涂覆于铜箔上烘干、冷压，得到负极极片。涂覆量为0.2g/cm 2，压实密度为1.7g/cm 3。 [Negative electrode sheet] Mix the negative active material artificial graphite, conductive agent carbon black, and binder styrene-butadiene rubber (SBR) in deionized water at a weight ratio of 92:2:6, then apply it on the copper foil and dry it , cold pressing to obtain the negative electrode piece. The coating amount is 0.2g/cm 2 and the compacted density is 1.7g/cm 3 .
【隔离膜】隔离膜采购自Cellgard企业，型号为cellgard2400。[Isolation film] The isolation film is purchased from Cellgard Company, the model is cellgard2400.
【电解液】将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按体积比1:1:1混合，然后将LiPF 6均匀溶解在上述溶液中得到电解液，其中LiPF 6的浓度为1mol/L。 [Electrolyte] Mix ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) in a volume ratio of 1:1:1, and then uniformly dissolve LiPF 6 in the above solution to obtain electrolysis liquid, in which the concentration of LiPF 6 is 1mol/L.
将正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正负极中间起到隔离的作用，并卷绕得到裸电芯。将裸电芯置于外包装中，注入电解液并封装，再经过化成及分容，得到锂离子二次全电池(下文也称“全电”)。全电池的长×宽×高＝148mm×28.5mm×97.5mm，电池的群裕度为91.0％。Stack the positive electrode piece, isolation film, and negative electrode piece in order so that the isolation film is between the positive and negative electrodes for isolation, and wind them to obtain a bare cell. The bare battery core is placed in the outer packaging, electrolyte is injected and packaged, and then through chemical formation and volume separation, a lithium-ion secondary full battery (hereinafter also referred to as "full battery") is obtained. The length × width × height of the full battery = 148mm × 28.5mm × 97.5mm, and the group margin of the battery is 91.0%.
实施例2Example 2
二次电池的制备与实施例1相同，区别在于，在正极活性材料的制备中，固体混合物中的硼酸锂、硼化钛和富锂锰基正极活性材料前驱体的重量比为0.4:3.0:96.6。The preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor in the solid mixture is 0.4:3.0: 96.6.
实施例3Example 3
二次电池的制备与实施例1相同，区别在于，在正极活性材料的制备中，固体混合物中的硼酸锂、硼化钛和富锂锰基正极活性材料前驱体的重量比为1.5:3.0:95.5。The preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor in the solid mixture is 1.5:3.0: 95.5.
实施例4Example 4
二次电池的制备与实施例1相同，区别在于，在正极活性材料的制备中，固体混合物中的硼酸锂、硼化钛和富锂锰基正极活性材料前驱体的重量比为5.4:3.0:91.6。The preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor in the solid mixture is 5.4:3.0: 91.6.
实施例5Example 5
二次电池的制备与实施例1相同，区别在于，在正极活性材料的制备中，固体混合物中的硼酸锂、硼化钛和富锂锰基正极活性材料前驱体的重量比为9.3:3.1:87.6。The preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor in the solid mixture is 9.3:3.1: 87.6.
实施例6Example 6
二次电池的制备与实施例1相同，区别在于，在正极活性材料的制备中，固体混合物中的硼酸锂、硼化钛和富锂锰基正极活性材料前驱体的重量比为15.7:3.2:81.1。The preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor in the solid mixture is 15.7:3.2: 81.1.
实施例7Example 7
二次电池的制备与实施例1相同，区别在于，富锂锰基正极活性材料前驱体Ni 0.3Mn 0.7CO 3的Dv50为5μm。 The preparation of the secondary battery is the same as in Example 1, except that the Dv50 of the lithium-rich manganese-based cathode active material precursor Ni 0.3 Mn 0.7 CO 3 is 5 μm.
实施例8Example 8
二次电池的制备与实施例1相同，区别在于，富锂锰基正极活性材料前驱体Ni 0.3Mn 0.7CO 3的Dv50为13μm。 The preparation of the secondary battery is the same as in Example 1, except that the Dv50 of the lithium-rich manganese-based cathode active material precursor Ni 0.3 Mn 0.7 CO 3 is 13 μm.
实施例9Example 9
二次电池的制备与实施例1相同，区别在于，富锂锰基正极活性材料前驱体Ni 0.3Mn 0.7CO 3的Dv50为20μm。 The preparation of the secondary battery is the same as in Example 1, except that the Dv50 of the lithium-rich manganese-based cathode active material precursor Ni 0.3 Mn 0.7 CO 3 is 20 μm.
实施例10Example 10
二次电池的制备与实施例1相同，区别在于，在正极活性材料的制备中，固体混合物中的硼酸锂、硼化钛和富锂锰基正极活性材料前驱体(Dv50为7μm)的重量比为6.0:0.4:93.6。The preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor (Dv50 is 7 μm) in the solid mixture is 6.0:0.4:93.6.
实施例11Example 11
二次电池的制备与实施例1相同，区别在于，在正极活性材料的制备中，固体混合物中的硼酸锂、硼化钛和富锂锰基正极活性材料前驱体(Dv50为7μm)的重量比为6.0:0.8:93.2。The preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor (Dv50 is 7 μm) in the solid mixture is 6.0:0.8:93.2.
实施例12Example 12
二次电池的制备与实施例1相同，区别在于，在正极活性材料的制备中，固体混合物中的硼酸锂、硼化钛和富锂锰基正极活性材料前驱体(Dv50为8μm)的重量比为6.1:2.3:91.6。The preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor (Dv50 is 8 μm) in the solid mixture is 6.1:2.3:91.6.
实施例13Example 13
二次电池的制备与实施例1相同，区别在于，在正极活性材料的制备中，固体混合物中的硼酸锂、硼化钛和富锂锰基正极活性材料前驱体(Dv50为8μm)的重量比为6.2:4.6:89.2。The preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor (Dv50 is 8 μm) in the solid mixture is 6.2:4.6:89.2.
实施例14Example 14
二次电池的制备与实施例1相同，区别在于，在正极活性材料的制备中，固体混合物中的硼酸锂、硼化钛和富锂锰基正极活性材料前驱体(Dv50为10μm)的重量比为6.2:7.8:86.0。The preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the weight ratio of lithium borate, titanium boride and lithium-rich manganese-based positive active material precursor (Dv50 is 10 μm) in the solid mixture is 6.2:7.8:86.0.
实施例15Example 15
二次电池的制备与实施例1相同，区别在于，在正极活性材料的制备中，快离子导体前驱体为二氧化硅。The preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the fast ion conductor precursor is silicon dioxide.
实施例16Example 16
二次电池的制备与实施例1相同，区别在于，在正极活性材料的制备中，快离子导体前驱体为磷酸锂。The preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the fast ion conductor precursor is lithium phosphate.
实施例17Example 17
二次电池的制备与实施例1相同，区别在于，在正极活性材料的制备中，金属化合物导电剂为氮化钛。The preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the metal compound conductive agent is titanium nitride.
实施例18Example 18
二次电池的制备与实施例1相同，区别在于，在正极活性材料的制备中，金属化合物导电剂为碳化钛。The preparation of the secondary battery is the same as in Example 1, except that in the preparation of the positive active material, the metal compound conductive agent is titanium carbide.
对比例1Comparative example 1
二次电池的制备与实施例1相同，区别在于，在(2)正极活性材料的制备中，直接将(1)获得的富锂锰基正极活性材料前驱体Ni 0.3Mn 0.7CO 3与锂源碳酸锂以重量比为100:50混合均匀后，在空气气氛下在800℃下烧结8h，得到富锂锰基正极活性材料0.4Li 2MnO 3·0.6LiNi 0.5Mn 0.5O 2，并使用该富锂锰基正极活性材料制备扣式电池。 The preparation of the secondary battery is the same as in Example 1, except that in (2) the preparation of the positive electrode active material, the lithium-rich manganese-based positive electrode active material precursor Ni 0.3 Mn 0.7 CO 3 obtained in (1) is directly mixed with the lithium source After mixing lithium carbonate evenly with a weight ratio of 100:50, it was sintered at 800°C for 8 hours in an air atmosphere to obtain a lithium-rich manganese-based cathode active material 0.4Li 2 MnO 3 ·0.6LiNi 0.5 Mn 0.5 O 2 , and use the rich Lithium manganese-based cathode active materials are used to prepare button batteries.
二、相关参数的测试2. Testing of relevant parameters
(1)压实密度测试(1) Compaction density test
根据GB/T 24533-2009测定正极活性材料5吨(5T)压力下的压实密度。取一定量的正极活性材料的粉末放于压实专用模具中,然后将模具放在压实密度仪器上。施加5T的压力，在设备上读出5T压力下粉末的厚度(卸压后的厚度)，通过ρ＝m/v，计算出压实密度。The compacted density of the positive active material under a pressure of 5 tons (5T) is measured according to GB/T 24533-2009. Take a certain amount of positive active material powder and place it in a special compaction mold, and then place the mold on the compaction density instrument. Apply a pressure of 5T, read the thickness of the powder under 5T pressure on the equipment (thickness after pressure relief), and calculate the compacted density through ρ = m/v.
测试结果参见表1。See Table 1 for test results.
(2)粒径测试(2) Particle size test
根据GB/T 19077.1-2016/ISO 13320:2009(粒度分布激光衍射法)测定正极活性材料的粒径。取一洁净烧杯，加入适量的上述正极活性材料，加入适量纯水，超声120W/5min确保材料粉末在水中完全分散。溶液倒入激光粒度分析仪(马尔文公司，型号：Mastersizer3000)的进样塔后随溶液循环到测试光路***，颗粒在激光束的照射下，通过接受和测量散向光的能量分布可得到颗粒的粒度分布特征(遮光度：8-12％)，读取Dv50的相应数值。The particle size of the cathode active material is measured according to GB/T 19077.1-2016/ISO 13320:2009 (particle size distribution laser diffraction method). Take a clean beaker, add an appropriate amount of the above positive active material, add an appropriate amount of pure water, and ultrasonic at 120W/5min to ensure that the material powder is completely dispersed in the water. The solution is poured into the injection tower of the laser particle size analyzer (Malvern Company, model: Mastersizer3000) and then circulated to the test optical system with the solution. The particles are irradiated by the laser beam and can be obtained by receiving and measuring the energy distribution of the scattered light. Particle size distribution characteristics (opacity: 8-12%), read the corresponding value of Dv50.
结果参见表1。See Table 1 for results.
(3)包覆层厚度测试(3) Covering layer thickness test
使用透射电子显微镜(STEM，ThermoFisher，Talos F200i)结合侧插式的可伸缩能量色散X射线光谱(EDS，ThermoFisher)，对显示画面中的材料进行线扫(Line Scan Analysis)。其中，加速电压50kV，放大倍数100kx，束流介于500～1000pA之间。得到包覆层中特征元素(以 实施例1为例，其可以为金属化合物导电剂中的钛)、富锂锰基基体材料中特征元素(以实施例1为例，其为锰)个数(Counts)线扫图谱。根据相应元素个数比例确定包覆层以及富锂锰基基体材料表面，从而可得出包覆层厚度。在正极活性材料颗粒上随机选取5个位置分别测量包覆层的厚度，对测量结果取算数平均值。Using a transmission electron microscope (STEM, ThermoFisher, Talos F200i) combined with a side-inserted scalable energy-dispersive X-ray spectrometer (EDS, ThermoFisher), a line scan (Line Scan Analysis) is performed on the materials in the display screen. Among them, the acceleration voltage is 50kV, the amplification factor is 100kx, and the beam current is between 500 and 1000pA. Obtain the number of characteristic elements in the coating layer (taking Example 1 as an example, it can be titanium in the metal compound conductive agent) and the characteristic elements in the lithium-rich manganese-based base material (taking Example 1 as an example, it can be manganese) (Counts) line scan chart. The coating layer and the surface of the lithium-rich manganese-based base material are determined according to the proportion of the corresponding element numbers, so that the thickness of the coating layer can be obtained. The thickness of the coating layer was measured at 5 randomly selected positions on the positive active material particles, and the arithmetic average of the measurement results was taken.
结果参见表1。See Table 1 for results.
三、二次电池性能的测试3. Testing of secondary battery performance
(1)25℃下循环容量保持率(1) Cycle capacity retention rate at 25°C
在25℃下，以1C的恒定电流充电至4.35V，后以4.35V恒压充电至电流降到0.05C，再以1C的恒定电流放电至2.5V，得首周放电比容量(Cd1)；如此反复充放电至第500周，得到二次电池循环500周后的放电比容量记为Cdn。容量保持率＝循环500周后的放电比容量(Cdn)/首周放电比容量(Cd1)。At 25°C, charge to 4.35V with a constant current of 1C, then charge with a constant voltage of 4.35V until the current drops to 0.05C, and then discharge to 2.5V with a constant current of 1C to obtain the first-week discharge specific capacity (Cd1); Charge and discharge are repeated in this way until the 500th cycle, and the discharge specific capacity of the secondary battery after 500 cycles is recorded as Cdn. Capacity retention rate=discharge specific capacity after 500 cycles (Cdn)/discharge specific capacity in the first cycle (Cd1).
结果参见表1。See Table 1 for results.
(2)1C放电倍率性能测试(2)1C discharge rate performance test
在25℃下，将各实施例和对比例的二次电池以0.1C倍率恒流充电至4.35V，再恒压充电至电流为0.05C，静置5min，再以0.1C倍率恒流放电至2V，记录此时的放电容量，即为0.1C放电容量；静置30min，然后将二次电池以1C倍率恒流充电至4.35V，再恒压充电至电流为0.05C，静置5min，再以1C倍率恒流放电至2V，记录此时的放电容量，即为1C放电容量；At 25°C, the secondary batteries of each example and comparative example were charged to 4.35V at a constant current rate of 0.1C, then charged at a constant voltage until the current was 0.05C, left to stand for 5 minutes, and then discharged at a constant current rate of 0.1C to 2V, record the discharge capacity at this time, which is the 0.1C discharge capacity; let it stand for 30 minutes, then charge the secondary battery with a constant current at a rate of 1C to 4.35V, then charge with a constant voltage until the current is 0.05C, let it stand for 5 minutes, and then Discharge to 2V at a constant current rate of 1C, and record the discharge capacity at this time, which is the 1C discharge capacity;
电池的倍率性能1C/0.1C(％)＝1C放电容量/0.1C放电容量×100％。The rate performance of the battery is 1C/0.1C (%) = 1C discharge capacity/0.1C discharge capacity × 100%.
结果参见表1。See Table 1 for results.
(3)3C充电恒流比测试(3) 3C charging constant current ratio test
在25℃恒温环境下，将各实施例和对比例的二次电池以1/3C放电至2.5V。静置5min，按照1/3C充电至4.3V，然后在4.3V下恒压充电至电流≤0.05mA。静置5min，记录此时的充电容量为C0。按照1/3C放电至 2.5V，静置5min，再按照3C充电至4.3V，静置5min，记录此时的充电容量为C1。3C充电恒流比即为C1/C0*100％。In a constant temperature environment of 25°C, the secondary batteries of each example and comparative example were discharged to 2.5V at 1/3C. Let it stand for 5 minutes, charge to 4.3V at 1/3C, and then charge at a constant voltage of 4.3V until the current is ≤0.05mA. Let it stand for 5 minutes, and record the charging capacity at this time as C0. Discharge to 2.5V according to 1/3C, let it sit for 5 minutes, then charge to 4.3V according to 3C, let it stand for 5 minutes, and record the charging capacity at this time as C1. The 3C charging constant current ratio is C1/C0*100%.
结果参见表1。See Table 1 for results.
Figure PCTCN2022112738-appb-000001
Figure PCTCN2022112738-appb-000001
由以上内容可以看出，与对比例1的不具有包覆层的富锂锰基正极活性材料相比，本申请的正极活性材料具有更好的循环性能和倍率性能，这正是由于本申请的正极活性材料是由一次颗粒堆叠形成的二次颗粒，在所述一次颗粒的基体材料外表面构建了形成连续的离子和电子通道的均质复合包覆层，有利于离子与电子的传输。It can be seen from the above that compared with the lithium-rich manganese-based cathode active material without a coating layer in Comparative Example 1, the cathode active material of the present application has better cycle performance and rate performance. This is precisely because of the The cathode active material is a secondary particle formed by stacking primary particles. A homogeneous composite coating layer forming a continuous ion and electron channel is constructed on the outer surface of the matrix material of the primary particle, which is conducive to the transmission of ions and electrons.
需要说明的是，本申请不限定于上述实施方式。上述实施方式仅为示例，在本申请的技术方案范围内具有与技术思想实质相同的构成、发挥相同作用效果的实施方式均包含在本申请的技术范围内。此外，在不脱离本申请主旨的范围内，对实施方式施加本领域技术人员能够想到的各种变形、将实施方式中的一部分构成要素加以组合而构筑的其它方式也包含在本申请的范围内。It should be noted that the present application is not limited to the above-described embodiment. The above-mentioned embodiments are only examples. Within the scope of the technical solution of the present application, embodiments that have substantially the same structure as the technical idea and exert the same functions and effects are included in the technical scope of the present application. In addition, within the scope that does not deviate from the gist of the present application, various modifications that can be thought of by those skilled in the art are made to the embodiments, and other forms constructed by combining some of the constituent elements of the embodiments are also included in the scope of the present application. .

Claims (17)

  1. 一种正极活性材料，其特征在于，所述正极活性材料为由一次颗粒堆叠形成的二次颗粒，其中所述一次颗粒包括富锂锰基基体材料和位于所述富锂锰基基体材料表面的包覆层，所述包覆层包括快离子导体和金属化合物导电剂。A positive active material, characterized in that the positive active material is a secondary particle formed by stacking primary particles, wherein the primary particles include a lithium-rich manganese-based matrix material and a lithium-rich manganese-based matrix material located on the surface of the lithium-rich manganese-based matrix material. The coating layer includes a fast ion conductor and a metal compound conductive agent.
  2. 根据权利要求1所述的正极活性材料，其特征在于，所述快离子导体选自硅酸锂、磷酸锂、硼酸锂、铌酸锂、铝酸锂、锆酸锂和焦磷酸锂中的一种或多种，可选地，所述快离子导体选自硅酸锂、磷酸锂和硼酸锂中的一种或多种；可选地，所述快离子导体的量为0.5-20重量％、可选为2-12重量％，基于所述正极活性材料的重量计。The cathode active material according to claim 1, characterized in that the fast ion conductor is selected from one of lithium silicate, lithium phosphate, lithium borate, lithium niobate, lithium aluminate, lithium zirconate and lithium pyrophosphate. One or more kinds, optionally, the fast ion conductor is selected from one or more kinds of lithium silicate, lithium phosphate and lithium borate; optionally, the amount of the fast ion conductor is 0.5-20% by weight. , optionally 2-12% by weight, based on the weight of the cathode active material.
  3. 根据权利要求1所述的正极活性材料，其特征在于，所述金属化合物导电剂选自碳化钛、氮化钛和硼化钛中的一种或多种；可选地，所述金属化合物导电剂的量为0.5-10重量％、可选为1-6重量％，基于所述正极活性材料的重量计。The cathode active material according to claim 1, wherein the metal compound conductive agent is selected from one or more of titanium carbide, titanium nitride and titanium boride; optionally, the metal compound conducts electricity The amount of the agent is 0.5-10% by weight, optionally 1-6% by weight, based on the weight of the cathode active material.
  4. 根据权利要求1-3中任一项所述的正极活性材料，其特征在于，所述正极活性材料中的所述快离子导体与所述金属化合物导电剂的重量比为1.3-3:1，可选为1.7-2.7:1。The cathode active material according to any one of claims 1 to 3, characterized in that the weight ratio of the fast ion conductor to the metal compound conductive agent in the cathode active material is 1.3-3:1, Optional 1.7-2.7:1.
  5. 根据权利要求1-3中任一项所述的正极活性材料，其特征在于，所述富锂锰基基体材料的化学式为xLi 2MnO 3·(1-x)LiMO 2，其中所述M为选自Fe、Al、Co、Mn、Ni、Cr、Ti、Mo、Nb、Zr、Sn、V、Mg、Cu、Zn、B、Na、Ca和Ru中的一种或多种的组合，可选地，所述M为选自Co、Ni、Cr、V、Mo、Mn、Al、Nb和Ti中的一种或多种的组合，且0＜x＜1。 The cathode active material according to any one of claims 1-3, wherein the chemical formula of the lithium-rich manganese-based matrix material is xLi 2 MnO 3 ·(1-x)LiMO 2 , wherein the M is One or more combinations selected from Fe, Al, Co, Mn, Ni, Cr, Ti, Mo, Nb, Zr, Sn, V, Mg, Cu, Zn, B, Na, Ca and Ru can be Optionally, the M is one or a combination of more selected from Co, Ni, Cr, V, Mo, Mn, Al, Nb and Ti, and 0<x<1.
  6. 根据权利要求1-3中任一项所述的正极活性材料，其特征在于，所述正极活性材料的Dv50为5-20μm、可选为7-13μm，所述一次颗粒的Dv50为0.05-1μm、可选为0.1-0.4μm。The positive active material according to any one of claims 1 to 3, characterized in that the Dv50 of the positive active material is 5-20 μm, optionally 7-13 μm, and the Dv50 of the primary particles is 0.05-1 μm. , optional 0.1-0.4μm.
  7. 根据权利要求1-3中任一项所述的正极活性材料，其特征在于，所述正极活性材料在5吨力下的压实密度为2.4-3.4g/cm 3，可选为2.7-3.2g/cm 3。 The positive active material according to any one of claims 1 to 3, characterized in that the compacted density of the positive active material under 5 tons of force is 2.4-3.4g/cm 3 , optionally 2.7-3.2 g/cm 3 .
  8. 根据权利要求1-3中任一项所述的正极活性材料，其特征在于，所述包覆层的厚度为0.005-0.2μm、可选为0.01-0.1μm，更可选为 0.04-0.08μm。The cathode active material according to any one of claims 1-3, characterized in that the thickness of the coating layer is 0.005-0.2 μm, optionally 0.01-0.1 μm, and more optionally 0.04-0.08 μm. .
  9. 一种制备正极活性材料的方法，其特征在于，包括以下步骤：A method for preparing cathode active material, characterized in that it includes the following steps:
    S1)将富锂锰基正极活性材料前驱体在惰性气氛中破碎，得到富锂锰基正极活性材料前驱体的一次颗粒；S1) Crush the lithium-rich manganese-based cathode active material precursor in an inert atmosphere to obtain primary particles of the lithium-rich manganese-based cathode active material precursor;
    S2)将快离子导体前驱体、金属化合物导电剂和分散剂聚乙烯吡咯烷酮加入水中并混合均匀，再向其中加入步骤S1)的富锂锰基正极活性材料前驱体的一次颗粒，混合均匀，得到固体混合物的悬浊液；S2) Add the fast ion conductor precursor, metal compound conductive agent and dispersant polyvinylpyrrolidone into water and mix evenly, then add the primary particles of the lithium-rich manganese-based cathode active material precursor of step S1) into the water and mix evenly to obtain Suspensions of solid mixtures;
    S3)将步骤S2)的固体混合物的悬浊液经喷雾干燥二次造粒，得到正极活性材料前驱体粉末；S3) spray-dry the suspension of the solid mixture in step S2) for secondary granulation to obtain positive electrode active material precursor powder;
    S4)将步骤S3)的正极活性材料前驱体粉末与锂源混合均匀，经烧结，得到正极活性材料，S4) Mix the cathode active material precursor powder and the lithium source in step S3) evenly, and sinter them to obtain the cathode active material,
    所述正极活性材料为由一次颗粒堆叠形成的二次颗粒，其中所述一次颗粒包括富锂锰基基体材料和位于所述富锂锰基基体材料表面的包覆层，所述包覆层包括快离子导体和金属化合物导电剂。The positive active material is a secondary particle formed by stacking primary particles, wherein the primary particle includes a lithium-rich manganese-based matrix material and a coating layer located on the surface of the lithium-rich manganese-based matrix material, and the coating layer includes Fast ion conductor and metal compound conductive agent.
  10. 根据权利要求9的一种制备正极活性材料的方法，其特征在于，在所述步骤S1)中，所述富锂锰基正极活性材料前驱体的一次颗粒的Dv50为0.05-1.1μm、可选为0.1-0.4μm。A method for preparing a cathode active material according to claim 9, characterized in that in the step S1), the Dv50 of the primary particles of the lithium-rich manganese-based cathode active material precursor is 0.05-1.1 μm, optional is 0.1-0.4μm.
  11. 根据权利要求9或10所述的制备正极活性材料的方法，其特征在于，在所述步骤S2)中，所述固体混合物包含快离子导体前驱体、金属化合物导电剂和富锂锰基正极活性材料前驱体的一次颗粒，The method for preparing a cathode active material according to claim 9 or 10, characterized in that, in the step S2), the solid mixture contains a fast ion conductor precursor, a metal compound conductive agent and a lithium-rich manganese-based cathode active material. Primary particles of material precursor,
    其中，所述快离子导体前驱体选自二氧化硅、磷酸锂、硼酸锂、五氧化二铌、氧化铝、二氧化锆和磷酸二氢锂中的一种或多种，可选地，所述快离子导体前驱体选自二氧化硅、磷酸锂和硼酸锂中的一种或多种；可选地，所述快离子导体的量为0.4-16重量％、可选为1.5-9.5重量％，基于所述固体混合物的重量计，且Wherein, the fast ion conductor precursor is selected from one or more of silicon dioxide, lithium phosphate, lithium borate, niobium pentoxide, alumina, zirconium dioxide and lithium dihydrogen phosphate. Optionally, the The fast ion conductor precursor is selected from one or more of silicon dioxide, lithium phosphate and lithium borate; optionally, the amount of the fast ion conductor is 0.4-16% by weight, optionally 1.5-9.5% by weight %, based on the weight of the solid mixture, and
    所述金属化合物导电剂选自碳化钛、氮化钛和硼化钛中的一种或多种；可选地，所述金属化合物导电剂的量为0.4-8重量％、可选为0.8-5重量％，基于所述固体混合物的重量计。The metal compound conductive agent is selected from one or more of titanium carbide, titanium nitride and titanium boride; optionally, the amount of the metal compound conductive agent is 0.4-8% by weight, optionally 0.8- 5% by weight, based on the weight of the solid mixture.
  12. 根据权利要求9或10所述的制备正极活性材料的方法，其特征在于，在所述步骤S4)中，所述烧结的气氛为氧气、空气或压缩空气，烧结温度为700-1000℃，烧结时间为5-10h。The method for preparing a cathode active material according to claim 9 or 10, characterized in that, in the step S4), the sintering atmosphere is oxygen, air or compressed air, the sintering temperature is 700-1000°C, and the sintering temperature is 700-1000°C. The time is 5-10h.
  13. 一种正极极片，其特征在于，包括正极集流体以及设置在正极集流体至少一个表面的正极膜层，所述正极膜层包括权利要求1-8中任一项所述的正极活性材料或通过权利要求9-12中任一项所述的方法制备的正极活性材料，并且所述正极活性材料在所述正极膜层中的含量为10重量％以上，基于所述正极膜层的总重量计。A positive electrode sheet, characterized in that it includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, and the positive electrode film layer includes the positive electrode active material according to any one of claims 1 to 8 or The cathode active material prepared by the method of any one of claims 9-12, and the content of the cathode active material in the cathode film layer is more than 10% by weight, based on the total weight of the cathode film layer count.
  14. 一种二次电池，其特征在于，包括权利要求1-8中任一项所述的正极活性材料或通过权利要求9-12中任一项所述的方法制备的正极活性材料。A secondary battery, characterized by comprising the cathode active material according to any one of claims 1 to 8 or the cathode active material prepared by the method according to any one of claims 9 to 12.
  15. 一种电池模块，其特征在于，包括权利要求14所述的二次电池。A battery module comprising the secondary battery according to claim 14.
  16. 一种电池包，其特征在于，包括权利要求15所述的电池模块。A battery pack, characterized by comprising the battery module according to claim 15.
  17. 一种用电装置，其特征在于，包括选自权利要求14所述的二次电池、权利要求15所述的电池模块或权利要求16所述的电池包中的至少一种。An electric device, characterized in that it includes at least one selected from the group consisting of the secondary battery according to claim 14, the battery module according to claim 15, or the battery pack according to claim 16.
PCT/CN2022/112738 2022-08-16 2022-08-16 Positive electrode active material and preparation method therefor, positive electrode plate, secondary battery, battery module, battery pack and electric device WO2024036472A1 (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105047921A (en) * 2015-07-14 2015-11-11 宁夏共享新能源材料有限公司 Lithium ion battery cathode material composite lithium iron phosphate and preparation method thereof and lithium ion battery
CN105428637A (en) * 2014-09-18 2016-03-23 宁德时代新能源科技有限公司 Lithium ion battery, positive electrode material of lithium ion battery and preparation method for positive electrode material
CN111435747A (en) * 2020-01-17 2020-07-21 蜂巢能源科技有限公司 Cobalt-free layered cathode material, preparation method thereof and lithium ion battery
CN112542583A (en) * 2019-09-23 2021-03-23 珠海冠宇电池股份有限公司 Positive electrode active material and high-voltage lithium ion battery comprising same
CN113809331A (en) * 2020-06-17 2021-12-17 东营市海科新源化工有限责任公司 Multifunctional additive for lithium ion battery anode, preparation method of multifunctional additive and lithium ion battery
US20220045325A1 (en) * 2020-08-06 2022-02-10 Dongguan Poweramp Technology Limited Positive electrode material, electrochemical device containing same, and electronic device

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105428637A (en) * 2014-09-18 2016-03-23 宁德时代新能源科技有限公司 Lithium ion battery, positive electrode material of lithium ion battery and preparation method for positive electrode material
CN105047921A (en) * 2015-07-14 2015-11-11 宁夏共享新能源材料有限公司 Lithium ion battery cathode material composite lithium iron phosphate and preparation method thereof and lithium ion battery
CN112542583A (en) * 2019-09-23 2021-03-23 珠海冠宇电池股份有限公司 Positive electrode active material and high-voltage lithium ion battery comprising same
CN111435747A (en) * 2020-01-17 2020-07-21 蜂巢能源科技有限公司 Cobalt-free layered cathode material, preparation method thereof and lithium ion battery
CN113809331A (en) * 2020-06-17 2021-12-17 东营市海科新源化工有限责任公司 Multifunctional additive for lithium ion battery anode, preparation method of multifunctional additive and lithium ion battery
US20220045325A1 (en) * 2020-08-06 2022-02-10 Dongguan Poweramp Technology Limited Positive electrode material, electrochemical device containing same, and electronic device

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