WO2024020795A1 - 一种复合正极材料、其制备方法、二次电池、电池模块、电池包和用电装置 - Google Patents

一种复合正极材料、其制备方法、二次电池、电池模块、电池包和用电装置 Download PDF

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WO2024020795A1
WO2024020795A1 PCT/CN2022/108009 CN2022108009W WO2024020795A1 WO 2024020795 A1 WO2024020795 A1 WO 2024020795A1 CN 2022108009 W CN2022108009 W CN 2022108009W WO 2024020795 A1 WO2024020795 A1 WO 2024020795A1
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lithium
source
battery
cathode material
composite cathode
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PCT/CN2022/108009
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English (en)
French (fr)
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陈强
吴奇
范敬鹏
赵栋
王婧
柳娜
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宁德时代新能源科技股份有限公司
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Priority to PCT/CN2022/108009 priority Critical patent/WO2024020795A1/zh
Publication of WO2024020795A1 publication Critical patent/WO2024020795A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the technical field of secondary batteries, and in particular to a composite cathode material, its preparation method, secondary batteries, battery modules, battery packs and electrical devices.
  • secondary batteries have been widely used in energy storage power systems such as hydraulic, thermal, wind and solar power stations, as well as electric tools, electric bicycles, electric motorcycles, and electric vehicles. , military equipment, aerospace and other fields.
  • cathode material has an important impact on the electrochemical performance of the battery, such as gram capacity.
  • the increase in battery capacity brought by the new generation of cathode materials is often accompanied by a decrease in cycle performance and safety performance. Therefore, existing cathode materials still need to be improved.
  • This application aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of this application is to provide a composite cathode material to further improve the cycle performance, storage performance and safety performance of the battery.
  • a first aspect of the application provides a composite cathode material, including: a lithium-containing metal oxide and a coating layer disposed on at least a part of the lithium-containing metal oxide.
  • the coating layer is carbon composite iron manganese phosphate.
  • the general formula of lithium vanadium material and iron manganese phosphate vanadium lithium material is as shown in formula I,
  • M2 is selected from one or more of Ni, Co, Ti and Al.
  • the composite cathode material prepared by coating the lithium-containing metal oxide with the carbon composite lithium iron manganese phosphate material can improve the cycle capacity retention rate of the battery at room temperature and high temperature, and reduce the gas production volume per unit capacity of the battery at high temperature, that is, , improve the cycle performance, storage performance and safety performance of the battery. At the same time, the coating layer will not significantly reduce the capacity performance of the battery. Batteries using composite cathode materials as the cathode still have excellent capacity performance and first charge effect.
  • the mass content of the coating layer is 0.1% to 10%, based on the total mass of the composite cathode material.
  • Composite cathode materials with appropriate coating amounts can obtain batteries with high capacity performance, excellent cycle performance, storage performance and safety performance.
  • the mass fraction of carbon in the coating layer is 0.01% to 25%, based on the total mass of the coating layer.
  • Suitable quality carbon enables the coating layer to have low powder resistivity, high material stability and conductivity, which is beneficial to maintaining the high capacity performance of the battery.
  • the composite cathode material has a powder resistivity of 1000 to 5500 ⁇ cm.
  • the composite cathode material has better stability and better conductivity, which is beneficial to maintaining and improving the capacity performance of the battery.
  • the average particle diameter Dv50 of the composite cathode material is 8 to 12 ⁇ m. If the particle size of the composite cathode material is too large, it is not conducive to the insertion and deintercalation of lithium ions. If the particle size of the composite cathode material is too small, the material is easy to aggregate. The average particle size of the composite cathode material is within a suitable range so that the battery can exert excellent electrochemistry. performance and cycle performance.
  • the general formula of the lithium-containing metal oxide is as shown in Formula II,
  • M1 is selected from the alkali metal elements Na, K, Rb and Cs.
  • Q is selected from one or more of Al, Mg, Zr, Ti, W, Y, B, Co, Nb, Mo, Sb, Sr.
  • Lithium-containing metal oxides are high-nickel metal oxides with high energy density, which can enable batteries to have high capacity performance and power performance.
  • the second aspect of this application provides a method for preparing a composite cathode material, which includes the following steps:
  • a second mixture containing a lithium source and a nickel-cobalt-manganese precursor is subjected to a second sintering process.
  • the molar ratio of the lithium element in the lithium source to the sum of the nickel element, cobalt element, and manganese element in the nickel-cobalt-manganese precursor is 0.95 ⁇ 1.05, prepare lithium-containing metal oxides;
  • the carbon composite lithium iron manganese vanadium phosphate material and the lithium-containing metal oxide are subjected to a third sintering treatment to obtain a composite cathode material
  • the composite cathode material includes a lithium-containing metal oxide and a coating layer disposed on at least a portion of the lithium-containing metal oxide, and the coating layer is the carbon composite lithium iron manganese vanadium phosphate material,
  • the general formula of the iron manganese vanadium lithium phosphate material is shown in formula I,
  • M2 is selected from one or more of Ni, Co, Ti and Al.
  • the composite cathode material prepared by the above method, the carbon composite iron manganese vanadium lithium phosphate material is at least partially coated with lithium-containing metal oxide, can improve the cycle performance, storage performance and safety performance of the battery, and the battery capacity performance is higher The retention rate can even be further improved.
  • the mass ratio of the lithium-containing metal oxide to the carbon-composite iron-manganese-vanadium lithium phosphate material is 9:1 to 999:1.
  • the appropriate amount of coating can balance the high capacity performance of the battery with excellent cycle performance, storage performance and safety performance.
  • the molar ratio of the vanadium element in the vanadium source to the iron element in the iron source is 0.5:8 ⁇ 4:1. Controlling the molar ratio of vanadium and iron can improve the cycle performance, storage performance and safety performance of the battery while maintaining the high rate performance of the battery.
  • the mass ratio of the carbon element in the carbon source to the lithium iron manganese vanadium phosphate material is 1:9999 to 1:4.
  • the appropriate quality of carbon enables the carbon composite lithium iron manganese phosphate material to have low powder resistivity, helping to maintain the high capacity performance of the cathode material.
  • the sintering temperature of the first sintering process is 650°C to 800°C, and the sintering time of the first sintering process is 10 to 20 hours. Controlling the temperature and time of the first sintering process within a suitable range is beneficial to the preparation of carbon composite iron manganese vanadium lithium phosphate materials with low powder resistivity and suitable average particle size Dv50, so that they can be effectively coated with lithium-containing metal oxides. , thereby improving the cycle performance, storage performance and safety performance of the battery.
  • the first mixture also includes one or more of a nickel source, a cobalt source, a titanium source, and an aluminum source.
  • the nickel source, cobalt source, titanium source, and aluminum source are each selected from the group consisting of nickel elements. , one or more oxides, hydroxides, carbonates and phosphates of cobalt, titanium and aluminum. Doping the above elements can improve the stability of the coating layer, thereby optimizing the cycle performance, storage performance and safety performance of the battery.
  • the iron source is selected from one or more of ferric oxide and ferric tetroxide
  • the manganese source is selected from one or more of manganese dioxide and manganese tetroxide
  • the vanadium source is selected from One or more of vanadium trioxide and vanadium pentoxide
  • the phosphorus source is selected from one or more of ammonium phosphate, ammonium dihydrogen phosphate, and lithium phosphate
  • the carbon source is selected from carbon black, citric acid, One or more of polyethylene glycol, sucrose, and glucose.
  • the second mixture further includes an alkali metal compound, and the mass content of the alkali metal compound is 0 to 5.5%, based on the total mass of the second mixture.
  • Lithium-containing metal oxides are doped with alkali metals to optimize lithium ion diffusion efficiency, which improves the battery's rate performance, cycle performance, storage performance, and first discharge effect.
  • a third aspect of the application provides a secondary battery, including a positive electrode sheet, a separator, a negative electrode sheet, and an electrolyte.
  • the positive electrode sheet includes the composite positive electrode material in any embodiment of the first aspect.
  • the battery has good cycle performance, storage performance and safety performance.
  • a fourth aspect of the present application provides a battery module including the secondary battery of the third aspect.
  • the battery module has good cycle performance, storage performance and safety performance.
  • a fifth aspect of the present application provides a battery pack including four battery modules.
  • the battery pack has good cycle performance, storage performance and safety performance.
  • a sixth aspect of the present application provides an electrical device, including at least one of the secondary battery of the third aspect, the battery module of the fourth aspect, and the battery pack of the fifth aspect.
  • the electrical device has good endurance and safety.
  • Figure 1 is an SEM image of the composite cathode material prepared in Example 1 of the present invention.
  • Figure 2 is a 25°C cycle performance test chart of a secondary battery made of the composite cathode material prepared in Example 1 of the present invention.
  • FIG. 3 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • FIG. 4 is an exploded view of the secondary battery according to the embodiment of the present application shown in FIG. 3 .
  • FIG. 5 is a schematic diagram of a battery module according to an embodiment of the present application.
  • Figure 6 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 7 is an exploded view of the battery pack according to an embodiment of the present application shown in FIG. 6 .
  • FIG. 8 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, i.e., 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
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially.
  • step (c) means that step (c) may be added to the method in any order.
  • the method may include steps (a), (b) and (c). , may also include steps (a), (c) and (b), may also include steps (c), (a) and (b), etc.
  • condition "A or B” is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists) ; Or both A and B are true (or exist).
  • high-nickel lithium-containing metal oxides are often used as cathode materials to increase battery capacity.
  • the surface of high-nickel lithium-containing metal oxides is rich in defects and has high content of strongly oxidizing transition metal elements Ni, Co, Mn, etc., its side reactions with the electrolyte are more serious, so that the contact interface structure is easily destroyed. Transition metal elements such as Ni, Mn, Co, etc. are easily eluted and deposited on the anode, causing the internal resistance of the battery to increase, which in turn leads to serious cycle capacity depletion of the battery and reduces the cycle performance of the battery.
  • the surface structure of high-nickel-containing lithium metal oxides is very unstable under the catalysis of electrolyte.
  • this application proposes a composite cathode material, including: a lithium-containing metal oxide and a coating layer provided on at least a part of the lithium-containing metal oxide.
  • the coating layer is carbon composite iron manganese vanadium phosphate.
  • the general formula of lithium material, iron manganese vanadium lithium phosphate material is shown in formula I,
  • M2 is selected from one or more of Ni, Co, Ti and Al.
  • the carbon composite lithium iron manganese vanadium phosphate material is a composite material including carbon and lithium iron manganese vanadium phosphate material. It can be understood that carbon and lithium iron manganese vanadium phosphate materials can be compounded in any way, such as physical mixing, chemical compounding, etc. Specifically, carbon and lithium iron manganese vanadium phosphate materials can be composited through stirring, grinding, ultrasound, in-situ growth, grafting, coating, etc.
  • the carbon composite lithium iron manganese phosphate material includes one or more of Ni, Co, Ti, and Al.
  • the lithium iron manganese vanadium phosphate material has the advantages of good stability, high potential and high rate. Using it as a coating layer can protect the surface of the lithium-containing metal oxide and improve the stability of the surface of the lithium-containing metal oxide and the interface in contact with the electrolyte.
  • the composite cathode material prepared by coating the lithium-containing metal oxide with the carbon composite lithium iron manganese phosphate material can improve the cycle capacity retention rate of the battery at room temperature and high temperature, and reduce the gas production volume per unit capacity of the battery at high temperature, that is, , improve the cycle performance, storage performance and safety performance of the battery. At the same time, the coating layer will not significantly reduce the capacity performance of the battery. Batteries using composite cathode materials as the positive electrode still have excellent capacity performance and first charge effect.
  • the mass content of the coating layer is 0.1% to 10%, based on the total mass of the composite cathode material. In some embodiments, the mass content of the coating layer is 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%.
  • the mass content of the coating layer is too high, the mass content of the lithium-containing metal oxide will be too low, and the battery capacity will be reduced.
  • the mass content of the coating layer is too low, and the carbon composite lithium iron manganese phosphate material cannot be effectively coated to improve the cycle performance and storage performance of the battery.
  • the appropriate amount of coating can take into account the capacity performance, cycle performance and storage performance of the battery. It can further improve the cycle performance, storage performance and safety performance of the battery while maintaining or even improving the capacity performance and first discharge effect of the battery.
  • the mass fraction of carbon in the coating layer is 0.01% to 25%, based on the total mass of the coating layer. In some embodiments, the mass fraction of carbon in the coating layer can be selected from 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%.
  • a carbon content analyzer is used to test the mass content of carbon element in the carbon composite iron manganese vanadium lithium phosphate material.
  • the mass content of carbon element in the carbon composite lithium iron manganese phosphate material can be adjusted by changing the quality of the added carbon source in the process of preparing the carbon composite lithium iron manganese vanadium phosphate material.
  • the mass content of carbon element in the coating layer is too high, it will easily lead to a reduction in the proportion of lithium iron manganese vanadium phosphate in the carbon composite lithium iron manganese vanadium phosphate material, and the characteristics of good stability and high voltage platform of lithium iron manganese vanadium phosphate cannot be exerted. .
  • the mass content of carbon element in the coating layer is too low, and the conductivity of the coating layer is too low, making it impossible to effectively transport electrons.
  • the material and the coating layer have suitable powder resistivity, which makes it easy to realize the deintercalation of lithium ions. Even when the coating layer is added, the capacity performance and first efficiency of the battery can be further maintained or improved, and the battery performance will not be affected by the coating. Deteriorated by the addition of cladding.
  • the composite cathode material has a powder resistivity of 1000 to 5500 ⁇ cm. In some embodiments, the composite cathode material has a powder resistivity of 1100 ⁇ cm, 1500 ⁇ cm, 2000 ⁇ cm, 2500 ⁇ cm, 3000 ⁇ cm, 3500 ⁇ cm, 4000 ⁇ cm, 4500 ⁇ cm, 5000 ⁇ cm, 5500 ⁇ cm.
  • the term "powder resistivity” refers to a parameter used to characterize the conductive properties of the material itself, which is different from the resistivity of the pole piece.
  • the powder resistivity is measured using a tester such as a four-probe meter based on "Carbon Composite Lithium Iron Phosphate Cathode Material for Lithium-Ion Batteries” GB/T 30835-2014.
  • the composite cathode material has better stability and better conductivity, which is beneficial to maintaining and improving the capacity performance of the battery.
  • the average particle size Dv50 of the composite cathode material is 8-12 ⁇ m. In some embodiments, the average particle size Dv50 of the composite cathode material is 8.5 ⁇ m, 9 ⁇ m, 9.5 ⁇ m, 10 ⁇ m, 10.5 ⁇ m, 11 ⁇ m, 11.5 ⁇ m, or 12 ⁇ m.
  • the average particle size Dv50 is a well-known meaning in the art, indicating the particle size corresponding to when the cumulative volume distribution percentage of the material reaches 50%.
  • Methods and instruments known in the art can be used for determination. For example, you can refer to the GB/T 19077-2016 particle size distribution laser diffraction method and use a laser particle size analyzer to measure it.
  • the particle size of the composite cathode material is too large, it is not conducive to the insertion and deintercalation of lithium ions. If the particle size of the composite cathode material is too small, the material is easy to aggregate.
  • the average particle size of the composite cathode material is within a suitable range so that the battery can exert excellent electrochemistry. performance and cycle performance.
  • the general formula of the lithium-containing metal oxide is as shown in Formula II,
  • M1 is selected from the alkali metal elements Na, K, Rb and Cs.
  • Q is selected from one or more of Al, Mg, Zr, Ti, W, Y, B, Co, Nb, Mo, Sb, Sr.
  • lithium-containing metal oxides In the preparation process of lithium-containing metal oxides, carbonates, sulfates, chlorides or oxides of Na, K, Rb, and Cs are added for co-sintering to achieve doping of alkali metal elements. Lithium-containing metal oxides are doped with alkali metals to improve lithium ion diffusion efficiency, thereby maintaining the high capacity and high rate performance of the battery.
  • 0 ⁇ e1 ⁇ 0.05 In the preparation process of lithium-containing metal oxides, oxides, hydroxides, carbonates or phosphates of Al, Mg, Zr, Ti, W, Y, B, Co, Nb, Mo, Sb, Sr are added. Sintering achieves doping of transition metal elements. The doping of transition metal elements can improve the structural stability of lithium-containing metal oxides and stabilize the structural skeleton, thereby improving the cycle performance and high-rate performance of the battery.
  • Lithium-containing metal oxides contain high nickel content and have high energy density, which can enable batteries to have high capacity performance and power performance.
  • a method for preparing a composite cathode material including the following steps:
  • the second mixture containing the lithium source and the nickel-cobalt-manganese precursor is subjected to a second sintering process.
  • the molar ratio of the lithium element in the lithium source to the sum of the nickel element, cobalt element and manganese element in the nickel-cobalt-manganese precursor is 0.95 to 1.05. , Preparation of lithium-containing metal oxides;
  • the carbon composite lithium iron manganese phosphate material and the lithium-containing metal oxide are subjected to a third sintering treatment to obtain a composite cathode material.
  • the composite cathode material includes a lithium-containing metal oxide and a coating layer provided on at least a part of the lithium-containing metal oxide.
  • the coating layer is a carbon composite lithium iron manganese phosphate material. The formula is as shown in formula I,
  • M2 is selected from one or more of Ni, Co, Ti and Al.
  • the sintering temperature of the third sintering process is 100 ⁇ 400°C.
  • the sintering time of the third sintering process is 2 to 8 hours.
  • the third sintering process is performed under a reducing atmosphere, and the reducing atmosphere is nitrogen or argon.
  • the mass ratio of the lithium-containing metal oxide to the carbon-composite iron-manganese-vanadium lithium phosphate material is 9:1 to 999:1.
  • the content of lithium-containing metal oxides is too low, and it is difficult to maintain the high capacity performance of the battery.
  • the content of the carbon composite iron-manganese-vanadium lithium phosphate material is too low, and it cannot form an effective coating on the lithium-containing metal oxides.
  • the cycle performance and storage performance, Improvements in safety performance are limited.
  • the appropriate amount of coating can balance the high capacity performance of the battery with excellent cycle performance, storage performance and safety performance.
  • the lithium source is one or more of lithium carbonate, lithium hydroxide, lithium phosphate, lithium nitrate, and lithium acetate.
  • the iron source is one or both of ferric oxide and ferric tetroxide.
  • the manganese source is one or both of manganese dioxide and manganese tetroxide.
  • the vanadium source is one or both of vanadium trioxide and vanadium pentoxide.
  • the phosphorus source is one or more of ammonium phosphate, ammonium dihydrogen phosphate, and lithium phosphate.
  • the carbon source is one or more of carbon black, citric acid, polyethylene glycol, sucrose, and glucose.
  • a lithium source, an iron source, a manganese source, a vanadium source, a phosphorus source, and a carbon source are mixed, wherein the molar mass of the lithium metal element in the lithium source is equal to the molar mass of the iron element, manganese in the iron source, manganese source, and vanadium source.
  • the total molar mass ratio of the element and vanadium element is 0.95 to 1.05.
  • the first mixture including a lithium source, an iron source, a manganese source, a vanadium source, a phosphorus source, and a carbon source is refined by a sand mill and spray-dried before being subjected to a first sintering treatment.
  • Carbon composite lithium iron manganese phosphate material can improve the cycle performance, storage performance and safety performance of the battery.
  • the carbon composite lithium iron manganese phosphate material is compounded with carbon elements and has low powder resistivity, so that the composite cathode material using it as the coating layer does not require carbon doping post-processing, which solves the problem of conventional carbon coating post-processing. It can further improve the stability of cathode composite materials and reduce manufacturing costs.
  • the molar ratio of the vanadium element in the vanadium source to the iron element in the iron source is 0.5:8 ⁇ 4:1. In some embodiments, the molar ratio of the vanadium element in the vanadium source to the iron element in the iron source is 1:8, 1:7, 1:6, 1:5, 1:4, 1:3, 1:2 , 1:1, 2:1, 3:1.
  • the mass ratio of the carbon element in the carbon source to the lithium iron manganese vanadium phosphate material is 1:9999 to 1:4. In some embodiments, the mass content of carbon element in the carbon composite lithium iron manganese phosphate material can be selected from 1:999, 1:99, 1:9, 1:8, 1:7, 1:6, 1 :5.
  • the sintering temperature of the first sintering process is 650°C to 800°C, and the sintering time of the first sintering process is 10 to 20 hours.
  • the first sintering process is performed under a reducing atmosphere. In some embodiments, the first sintering process is performed under a nitrogen or argon atmosphere.
  • Controlling the sintering time of the first sintering process can control the nucleation and growth process of the carbon composite iron manganese vanadium lithium phosphate material. If the reaction time is too short or the reaction temperature is too low, it will easily lead to incomplete nucleation and growth of the carbon composite lithium iron manganese phosphate material and poor crystallinity of the material. If the reaction time is too long or the reaction temperature is too high, the carbon composite lithium iron manganese vanadium phosphate material will continue to grow after nucleation is completed, causing the particle size of the carbon composite lithium iron manganese vanadium phosphate material to be too large.
  • Controlling the temperature and time of the first sintering process within a suitable range is beneficial to preparing a carbon composite iron manganese vanadium lithium phosphate material with low powder resistivity, a suitable average particle size Dv50, and suitable as a coating layer.
  • the first mixture also includes one or more of a nickel source, a cobalt source, a titanium source, and an aluminum source.
  • the nickel source, cobalt source, titanium source, and aluminum source are each selected from the group consisting of nickel elements. , one or more oxides, hydroxides, carbonates and phosphates of cobalt, titanium and aluminum. Doping nickel, cobalt, titanium and aluminum elements improves the stability of the carbon composite iron manganese vanadium lithium phosphate material and further improves the cycle performance, storage performance and safety performance of the battery.
  • the sintering temperature of the second sintering treatment is 600-900°C, and the sintering time is 10-20 hours.
  • the second mixture also includes an alkali metal compound, and the mass content of the alkali metal compound is 0 to 5.5%, based on the total mass of the second mixture.
  • the alkali metal compound is a carbonate, sulfate, chloride or oxide of Na, K, Rb, Cs.
  • the second mixture includes an alkali metal compound to achieve alkali metal doping of the lithium-containing metal oxide, thereby improving the lithium ion diffusion efficiency of the cathode material, thereby optimizing the rate performance of the battery, and also improving the first discharge effect of the battery.
  • 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 composite positive electrode 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 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 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 positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as composite positive electrode materials, conductive agents, binders and any other components in a solvent (such as N -methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode piece can be obtained.
  • a solvent such as N -methylpyrrolidone
  • the negative electrode current collector has two opposite surfaces in its own thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base material.
  • the composite current collector can be formed by forming metal materials (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyterephthalate It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative active material may be a negative active material known in the art for batteries.
  • the negative active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, and the like.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon carbon composites, silicon nitrogen composites and silicon alloys.
  • the tin-based material may be selected from at least one of elemental tin, tin oxide compounds and tin alloys.
  • the present application is not limited to these materials, and other traditional materials that can be used as battery negative electrode active materials can also be used. Only one type of these negative electrode active materials may be used alone, or two or more types may be used in combination.
  • the negative electrode film layer optionally further includes a binder.
  • the binder may be selected from the group consisting of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), polysodium acrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polyacrylamide At least one of methacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the negative electrode film layer optionally further includes a conductive agent.
  • the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the negative electrode film layer optionally includes other auxiliaries, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
  • thickeners such as sodium carboxymethylcellulose (CMC-Na)
  • the negative electrode sheet of the full battery can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as negative active material, conductive agent, binder and any other components in a solvent (for example, in deionized water), a negative electrode slurry is formed; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet of the full battery can be obtained.
  • a solvent For example, in deionized water
  • a negative electrode slurry is formed; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet of the full battery can be obtained.
  • 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 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 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. 3 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. The specific number can be selected by those skilled in the art according to the application and capacity of the battery module.
  • FIG. 5 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.
  • Figure 8 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.
  • First sintering treatment Mix lithium carbonate, ferric oxide, manganese dioxide, vanadium trioxide, and ammonium dihydrogen phosphate at a molar ratio of 1:0.5:0.4:0.2:2, and add 5% of the mass of the mixed material
  • sucrose add a certain amount of water to make the solid content reach 40%.
  • Grind and refine it with a sand mill. Pour it into a mixing tank and mix it evenly. Then, the evenly mixed slurry is spray-dried to obtain a mixed powder. The material is put into a kiln for processing. Sintering, the sintering temperature is 700°C, the sintering time is 10 hours, the sintering atmosphere is nitrogen, and the carbon composite iron manganese vanadium lithium phosphate material is obtained by sintering.
  • Second sintering treatment mix lithium hydroxide, cathode material precursor Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 and alumina in a plow mixer according to a molar ratio of 1.05:0.99:0.01, and then mix the The mixed materials are put into the kiln for sintering.
  • the sintering temperature is 750°C
  • the sintering time is 15 hours
  • the sintering atmosphere is oxygen.
  • the lithium-containing metal oxide is obtained by mechanical crushing.
  • Third sintering treatment Mix the lithium-containing metal oxide and the carbon composite iron-manganese-vanadium lithium phosphate material evenly in a mass ratio of 95:5, and sinter them at 300°C for 5 hours in a nitrogen atmosphere to obtain a composite cathode material.
  • the composite cathode material, polyvinylidene fluoride (PVDF), and acetylene black were added to the solvent N-methylpyrrolidone (NMP) at a weight ratio of 90:5:5, and stirred in a drying room to form a slurry.
  • NMP solvent N-methylpyrrolidone
  • the above slurry is coated on aluminum foil, dried and cold pressed to form a positive electrode sheet.
  • the coating amount is 0.01g/cm 2 and the compacted density is 3.5g/cm 3 .
  • EC ethylene carbonate
  • EMC ethyl methyl carbonate
  • DEC diethyl carbonate
  • the isolation film was purchased from Cellgard Company, model number is Cellgard 2400.
  • the composite cathode material, polyvinylidene fluoride (PVDF), and acetylene black were added to the solvent N-methylpyrrolidone (NMP) at a weight ratio of 90:5:5, and stirred in a drying room to form a slurry.
  • NMP solvent N-methylpyrrolidone
  • the above slurry is coated on aluminum foil, dried and cold pressed to form a positive electrode sheet.
  • the coating amount is 0.01g/cm 2 and the compacted density is 3.5g/cm 3 .
  • EC ethylene carbonate
  • EMC ethyl methyl carbonate
  • DEC diethyl carbonate
  • PE porous polymer film is used as the isolation membrane.
  • the above-mentioned positive electrode pieces, isolation film, and negative electrode pieces are stacked in order, so that the isolation film is between the positive and negative electrodes to play an isolation role, and the bare battery core is obtained by winding.
  • the bare battery core is placed in the outer packaging, electrolyte is injected and packaged to obtain a full battery (hereinafter also referred to as "full battery”).
  • the length ⁇ width ⁇ height of the full battery 90mm ⁇ 30mm ⁇ 60mm, and the group margin of the battery is 91.0%.
  • the batteries of Examples 2 to 24 are prepared in a similar manner to the battery of Example 1.
  • Example 2 the mass fraction of carbon in the carbon composite lithium iron manganese phosphate material was adjusted by changing the mass fraction of sucrose added in the first sintering process.
  • Example 6 to 9 the temperature of the first sintering process was adjusted.
  • the time of the first sintering process was adjusted in Examples 10-13
  • the mass fraction of the coating layer was adjusted in Examples 14-17
  • the vanadium element in the vanadium source in the first sintering process was adjusted in Examples 18-21 It is matched with the molar ratio of the iron element in the iron source, and the specific parameters are shown in 1.
  • Example 22 sodium carbonate was added to the second sintering treatment, and the molar ratio of lithium hydroxide, sodium carbonate, cathode material precursor Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 and aluminum oxide was 1.03:0.02:0.99:0.01.
  • alumina, lithium carbonate, alumina, ferric oxide, manganese dioxide, vanadium trioxide, and diphosphate were added according to a molar ratio of 1:0.002:0.5:0.4:0.2:1. Ammonium hydrogen.
  • the cathode material precursor added in the second sintering process in Example 24 is Ni 0.92 Co 0.06 Mn 0.02 (OH) 2 .
  • the cathode material is a lithium-containing metal oxide without a coating layer
  • the coating material in Comparative Example 2 is a carbon composite lithium iron manganese phosphate material, and the specific parameters are shown in Table 1.
  • the test method is as follows:
  • the surface morphology of the composite cathode material was characterized using a field emission scanning electron microscope (Sigma300) from ZEISS Company in Germany.
  • Full cells were stored at 100% state of charge (SOC) at 70°C. Measure the open circuit voltage (OCV) and AC internal resistance (IMP) of the battery cells before, after and during storage to monitor SOC, and measure the volume of the battery cells. After every 48 hours of storage, the full battery was taken out, OCV and IMP were tested after leaving it for 1 hour, and the cell volume was measured using the drainage method after cooling to room temperature.
  • the drainage method is to first separately measure the gravity F1 of the battery cell using a balance that automatically converts units using dial data, then completely places the battery core in deionized water (density is known to be 1g/cm 3 ), and measures the gravity of the battery core at this time.
  • the battery core is recharged, charged with a constant current of 1C to 4.25V, and then charged with a constant voltage of 4.25V until the current drops to 0.05C. After the recharge is completed, the battery is placed in the furnace to continue testing.
  • the gas production/cell capacity is the gas production volume per unit capacity.
  • the composite cathode material provided by the present application includes: a lithium-containing metal oxide and a coating layer provided on at least a part of the lithium-containing metal oxide, including The coating is a carbon composite lithium iron manganese vanadium phosphate material.
  • the general formula of the iron manganese vanadium lithium phosphate material is as shown in Formula I,
  • M2 is selected from one or more of Ni, Co, Ti and Al.
  • the composite cathode material prepared by coating the lithium-containing metal oxide with the carbon composite lithium iron manganese phosphate material can improve the cycle capacity retention rate of the battery at room temperature and high temperature, and reduce the gas production volume per unit capacity of the battery at high temperature, that is, , improve the cycle performance, storage performance and safety performance of the battery. At the same time, the coating layer will not significantly reduce the capacity performance of the battery. Batteries using composite cathode materials as the positive electrode still have excellent capacity performance and first charge effect.
  • Example 1 From the comparison between Example 1 and Comparative Examples 1 to 2, it can be seen that compared with the traditional lithium iron manganese phosphate coating layer, the coating layer of the present application can further improve the environmental performance, storage performance and safety performance of the battery, while coating The coating of layers can also increase the gram capacity of the battery.
  • the mass content of the coating layer is 0.1% to 10%. Based on the total mass of the composite cathode material, the composite cathode material further improves the cycle performance, storage performance and safety of the battery. It can maintain or even improve the battery's capacity performance and first charge effect while maintaining performance.
  • the mass fraction of carbon in the coating layer is 0.01% to 25%. Based on the total mass of the coating layer, the coating layer has an appropriate powder resistivity and can easily achieve the removal of lithium ions. Embedded, even with the addition of a coating layer, the capacity performance and first efficiency of the battery can be further maintained or improved, and the battery performance will not be deteriorated due to the addition of the coating layer.
  • the powder resistivity of the composite cathode material is 1000 to 5500 ⁇ cm.
  • the powder resistivity of the composite cathode material is low, and the material stability and conductivity are higher, which helps To maintain and improve battery capacity.
  • the average particle size D50 of the composite cathode material is 8-12 ⁇ m. When it is optionally 8-10 ⁇ m, the composite cathode material can exhibit excellent electrochemical performance and cycle performance.
  • the composite cathode material when the molar ratio of vanadium element in the vanadium source to iron element in the iron source is 0.5:8-4:1, the composite cathode material further improves the cycle performance of the battery. , storage performance and safety performance while maintaining or even improving the battery's capacity performance and first charge effect.
  • doping the aluminum element in the carbon composite lithium iron manganese phosphate material can further improve the stability of the coating layer, thereby improving the cycle performance of the battery at high temperatures.
  • lithium-containing metal oxide is doped with alkali metal, and the first discharge effect, cycle performance and storage performance of the battery are improved.

Abstract

本申请提供了一种复合正极材料、其制备方法、二次电池、电池模块、电池包和用电装置。该复合正极材料包含含锂的金属氧化物以及设置在含锂的金属氧化物的至少一部分上的包覆层，包覆层为碳复合的磷酸铁锰钒锂材料，磷酸铁锰钒锂材料的通式如式I所示，LiFea1Mnb1Vc1M2d1PO4，式I其中，0.1≤a1≤0.8，0.1≤b1≤0.45，0.07≤c1≤0.3，0≤d1≤0.01，其中，M2选自Ni、Co、Ti、Al中的一种或多种。碳复合的磷酸铁锰钒锂材料至少部分包覆含锂的金属氧化物的复合正极材料能够提高电池的循环性能、存储性能以及安全性能。

Description

一种复合正极材料、其制备方法、二次电池、电池模块、电池包和用电装置 技术领域
本申请涉及二次电池技术领域，尤其涉及一种复合正极材料、其制备方法、二次电池、电池模块、电池包和用电装置。
背景技术
近年来，二次电池的应用范围越来越广泛，尤其是二次电池已广泛应用于水力、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。
随着市场对用电装置续航能力和安全性需求的提高，二次电池要求具有更为优异的包括容量性能、安全性能及循环性能在内的综合性能。正极材料对电池的电化学性能，如克容量有重要影响。然而，新一代正极材料带来电池容量提高的同时往往伴随着循环性能和安全性能的下降。因此，现有的正极材料仍有待改进。
发明内容
本申请旨在至少解决现有技术中存在的技术问题之一。为此，本申请的一个目的在于提供一种复合正极材料，以进一步提高电池的循环性能、存储性能以及安全性能。
本申请的第一方面提供了一种复合正极材料，包括：含锂的金属氧化物以及设置在含锂的金属氧化物的至少一部分上的包覆层，包覆层为碳复合的磷酸铁锰钒锂材料，磷酸铁锰钒锂材料的通式如式I所示，
LiFe a1Mn b1V c1M2 d1PO 4，式I
其中，0.1≤a1≤0.8，0.1≤b1≤0.45，0.07≤c1≤0.3，0≤d1≤0.01，其中，M2选自Ni、Co、Ti、Al中的一种或多种。
碳复合的磷酸铁锰钒锂材料包覆含锂的金属氧化物后制备的复合正极材料能够提高电池在常温和高温下的循环容量保持率、降低电池在高温下的单位容量产气体积，即，提高电池的循环性能、存储性能及安全性能，同时包覆层的包覆不会显著降低电池的容量性能，以复合正极材料作为正极的电池依然具有优异的容量性能和扣电首效。
在任意实施方式中，包覆层的质量含量为0.1％～10％，基于复合正极材料的总质量计。具有合适包覆量的复合正极材料能够获得兼具高容量性能、优异循环性能、存储性能和安全性能的电池。
在任意实施方式中，包覆层中碳的质量分数为0.01％～25％，基于包覆层的总质量计。合适质量的碳使得包覆层具有低的粉末电阻率，高的材料稳定性和导电性，有利于保持电池的高容量性能。
在任意实施方式中，复合正极材料的粉末电阻率为1000～5500Ω·cm。复合正极材料的粉末电阻率在此范围内时，复合正极材料具有更好的稳定性和更优异的导电性，有利于保持和提升电池的容量性能。
在任意实施方式中，复合正极材料的平均粒径Dv50为8～12μm。复合正极材料的粒径过大不利于锂离子的嵌入和脱嵌，复合正极材料的粒径过小，材料容易聚集，复合正极材料的平均粒径在合适范围内使得电池能够发挥优异的电化学性能和循环性能。
在任意实施方式中，含锂的金属氧化物的通式如式II所示，
Li 1.05-a2M1 a2(Ni b2Co c2Mn d2) 1-e2Q e2O 2，式II
式中，0≤a2≤0.1，0.7≤b2≤0.96，0.03≤c2≤0.2，0.01≤d2≤0.2，0≤e2≤0.05；其中，M1选自碱金属元素Na、K、Rb、Cs中的一种或多种，Q选自Al、Mg、Zr、Ti、W、Y、B、Co、Nb、Mo、Sb、Sr中的一种或多种。
含锂金属氧化物为高镍金属氧化物，具有高的能量密度，能够使得电池具有高的容量性能和功率性能。
本申请的第二方面提供一种复合正极材料的制备方法，包括以下步骤：
将包含锂源、铁源、锰源、钒源、磷源和碳源的第一混合物进行 第一烧结处理，制备碳复合的磷酸铁锰钒锂材料，
将包含锂源和镍钴锰前驱体的第二混合物进行第二烧结处理，所述锂源中的锂元素与所述镍钴锰前驱体中的镍元素、钴元素和锰元素总和的摩尔比为0.95～1.05，制备含锂的金属氧化物；
将所述碳复合的磷酸铁锰钒锂材料与所述含锂的金属氧化物进行第三烧结处理，得到复合正极材料，
所述复合正极材料包括含锂的金属氧化物以及设置在所述含锂的金属氧化物的至少一部分上的包覆层，所述包覆层为所述碳复合的磷酸铁锰钒锂材料，所述磷酸铁锰钒锂材料的通式如式I所示，
LiFe a1Mn b1V c1M2 d1PO 4，式I
其中，0.1≤a1≤0.8，0.1≤b1≤0.45，0.07≤c1≤0.3，0≤d1≤0.01，其中，M2选自Ni、Co、Ti、Al中的一种或多种。
通过上述方法制备的复合正极材料，碳复合的磷酸铁锰钒锂材料至少部分包覆含锂的金属氧化物，能够提高电池的循环性能、存储性能以及安全性能，且电池的容量性能具有较高的保持率甚至能够得到进一步提升。
在任意实施例中，在第三烧结处理中，含锂的金属氧化物与碳复合的磷酸铁锰钒锂材料与的质量比为9:1～999:1。合适的包覆量能够兼顾电池的高容量性能与优异的循环性能、存储性能和安全性能。
在任意实施方式中，在第一烧结处理中，钒源中的钒元素与铁源中的铁元素的摩尔比为0.5:8～4:1。控制钒元素与铁元素的摩尔比，可以在保持电池高倍率性能的同时提升电池的循环性能与存储性能、安全性能。
在任意实施方式中，碳源中碳元素的质量与磷酸铁锰钒锂材料的质量比为1:9999～1:4。合适质量的碳使得碳复合的磷酸铁锰钒锂材料具有低的粉末电阻率，有助于保持正极材料高的容量性能。
在任意实施方式中，第一烧结处理的烧结温度为650℃～800℃，第一烧结处理的烧结时间为10～20h。控制第一烧结处理的温度和时间在合适范围内有利于制备低粉末电阻率、合适平均粒径Dv50的碳 复合的磷酸铁锰钒锂材料，使其能够有效包覆于含锂的金属氧化物，进而提高电池的循环性能、存储性能和安全性能。
在任意实施例中，第一混合物中还包含镍源、钴源、钛源，铝源中的一种或多种，所述镍源、钴源、钛源，铝源分别选自包含镍元素、钴元素、钛元素、铝元素的氧化物、氢氧化物、碳酸盐和磷酸盐的一种或多种。掺杂上述元素能够提高包覆层的稳定性，进而优化电池的循环性能、存储性能和安全性能。
在任意实施例中，铁源选自三氧化二铁和四氧化三铁中的一种或多种；锰源选自二氧化锰和四氧化三锰中的一种或多种；钒源选自三氧化二钒和五氧化二钒中的一种或多种；磷源选自磷酸铵、磷酸二氢铵、磷酸锂中的一种或多种；碳源选自炭黑、柠檬酸、聚乙二醇、蔗糖、葡萄糖中的一种或多种。
在任意实施例中，第二混合物中还包括碱金属化合物，碱金属化合物的质量含量为0～5.5％，基于第二混合物的总质量计。含锂的金属氧化物经过碱金属掺杂，可优化锂离子扩散效率，使得电池的倍率性能、循环性能、存储性能、扣电首效均有所提高。
本申请的第三方面提供一种二次电池，包括正极极片、隔离膜、负极极片以及电解液，正极极片包括第一方面的任意实施方式中复合正极材料。该电池具有良好的循环性能、存储性能以及安全性能。
本申请的第四方面提供一种电池模块，包括第三方面的二次电池。该电池模块具有良好的循环性能、存储性能以及安全性能。
本申请的第五方面提供一种电池包，包括四方面的电池模块。该电池包具有良好的循环性能、存储性能以及安全性能。
本申请的第六方面提供一种用电装置，包括第三方面的二次电池、第四方面的电池模块、第五方面的电池包中的至少一种。该用电装置具有良好的续航能力和安全性。
上述说明仅是本申请技术方案的概述，为了能够更清楚了解本申请的技术手段，而可依照说明书的内容予以实施，并且为了让本申请的上述和其它目的、特征和优点能够更明显易懂，以下特举本申请的 具体实施方式。
附图说明
图1为本发明实施例1制备得到的复合正极材料的SEM图。
图2为本发明实施例1制备得到的复合正极材料制作二次电池的25℃循环性能测试图。
图3是本申请一实施方式的二次电池的示意图。
图4是图3所示的本申请一实施方式的二次电池的分解图。
图5是本申请一实施方式的电池模块的示意图。
图6是本申请一实施方式的电池包的示意图。
图7是图6所示的本申请一实施方式的电池包的分解图。
图8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。
附图标记说明：
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。
具体实施方式
以下，适当地参照附图详细说明具体公开了本申请的粘结剂、制备方法、电极、电池及用电装置的实施方式。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。
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。
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。
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。
如果没有特别的说明，本申请的所有步骤可以顺序进行，也可以随机进行，优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，所述提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。
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。
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)。
现有技术中常采用高镍含锂金属氧化物作为正极材料以提高电池容量。然而，由于高镍含锂金属氧化物表面富含缺陷且具有高含量 的强氧化性过渡金属元素Ni、Co、Mn等，其与电解液的副反应较为严重，以致接触界面结构易于被破坏，过渡金属元素Ni、Mn、Co等容易溶出并沉积到阳极，导致电池内阻增加，进而致使电池的循环容量衰竭严重，降低电池的循环性能。另外，高镍含锂金属氧化物在电解液的催化下表面结构很不稳定，遇到挤压或高温时很容易释氧并伴随放热现象，易于导致电芯热失控，严重的还会导致安全事故。虽然常规的包覆层处理能够在一定程度上提高循环性能和安全性能，但是提升幅度有限，难以满足市场对于新一代电池的需求。
[复合正极材料]
基于此，本申请提出了一种复合正极材料，包括：含锂的金属氧化物以及设置在含锂的金属氧化物的至少一部分上的包覆层，包覆层为碳复合的磷酸铁锰钒锂材料，磷酸铁锰钒锂材料的通式如式I所示，
LiFe a1Mn b1V c1M2 d1PO 4，式I
其中，0.1≤a1≤0.8，0.1≤b1≤0.45，0.07≤c1≤0.3，0≤d1≤0.01，其中，M2选自Ni、Co、Ti、Al中的一种或多种。
在一些实施方式中，碳复合的磷酸铁锰钒锂材料为包括碳与磷酸铁锰钒锂材料的复合材料。可以理解，碳与磷酸铁锰钒锂材料可以通过任意方式复合，如物理混合、化学复合等。具体地，碳与磷酸铁锰钒锂材料可以通过搅拌、研磨、超声、原位生长、接枝、包覆等方式实现复合。
在一些实施方式中，0<d2≤0.01，碳复合的磷酸铁锰钒锂材料中包括Ni、Co、Ti、Al中的一种或多种。
磷酸铁锰钒锂材料具有稳定性好、电位高、倍率高的优点。以其作为包覆层能够保护含锂的金属氧化物的表面，提高含锂的金属氧化物的表面和其与电解液接触的界面的稳定性。碳复合的磷酸铁锰钒锂材料包覆含锂的金属氧化物后制备的复合正极材料能够提高电池在常温和高温下的循环容量保持率、降低电池在高温下的单位容量产气体积，即，提高电池的循环性能、存储性能及安全性能，同时包覆层的包覆不会大幅度降低电池的容量性能，以复合正极材料作为正极的 电池依然具有优异的容量性能和扣电首效。
在一些实施方式中，包覆层的质量含量为0.1％～10％，基于复合正极材料的总质量计。在一些实施方式中，包覆层的质量含量为1％、2％、3％、4％、5％、6％、7％、8％、9％。
包覆层的质量含量过高会导致含锂的金属氧化物的质量含量过低，电池容量降低。包覆层的质量含量过低，碳复合的磷酸铁锰钒锂材料无法实现有效包覆，达到改善电池的循环性能和存储性能的效果。合适的包覆量能够兼顾电池的容量性能与循环性能和存储性能，在进一步提高电池的循环性能、存储性能及安全性能的同时能够保持、甚至提高电池的容量性能和扣电首效。
在一些实施方式中，包覆层中碳的质量分数为0.01％～25％，基于包覆层的总质量计。在一些实施方式中，包覆层中碳的质量分数可以选自0.1％、1％、2％、3％、4％、5％、6％、7％、8％、9％、10％、11％、12％、13％、14％、15％、16％、17％、18％、19％、20％、21％、22％、23％、24％、25％。
在一些实施方式中，使用碳含量分析仪测试碳元素在碳复合的磷酸铁锰钒锂材料中的质量含量。本文中，碳元素在碳复合的磷酸铁锰钒锂材料中的质量含量可以通过在制备碳复合的磷酸铁锰钒锂材料中的过程中改变加入的碳源的质量进行调节。
碳元素在包覆层中的质量含量过高容易导致碳复合的磷酸铁锰钒锂材料中磷酸铁锰钒锂的占比降低，无法发挥磷酸铁锰钒锂稳定性好、电压平台高的特点。碳元素在包覆层中的质量含量过低包覆层导电性过低，无法实现电子的有效传输。控制碳元素在碳复合的氧化物颗粒磷酸铁锰钒锂材料中的质量含量在合适范围内能够通过均匀的碳复合得到粒径分布均匀、碳元素分散性高的碳复合的磷酸铁锰钒锂材料，包覆层具有合适的粉末电阻率，容易实现锂离子的脱嵌，即便在包覆层添加的情况下，电池的容量性能和首效能够得到进一步保持或者提高，电池性能不会因包覆层的添加而恶化。
在一些实施方式中，复合正极材料的粉末电阻率为1000～5500Ω·cm。在一些实施方式中，复合正极材料的粉末电阻率为1100Ω·cm、1500Ω·cm、2000Ω·cm、2500Ω·cm、3000Ω·cm、3500Ω·cm、4000Ω·cm、4500Ω·cm、5000Ω·cm、5500Ω·cm。
在本文中，术语“粉末电阻率”指的是用于表征材料本身的导电性能的参数，其不同于极片的电阻率。通常，粉末电阻率是利用诸如四探针仪的测试仪，依据《锂离子电池用炭复合磷酸铁锂正极材料》GB/T 30835-2014进行测定的。
复合正极材料的粉末电阻率在此范围内时，复合正极材料具有更好的稳定性和更优异的导电性，有利于保持和提升电池的容量性能。
在一些实施方式中，复合正极材料的平均粒径Dv50为8～12μm。在一些实施方式中，复合正极材料的平均粒径Dv50为8.5μm、9μm、9.5μm、10μm、10.5μm、11μm、11.5μm、12μm。
在本文中，平均粒径Dv50为本领域公知的含义,表示材料累计体积分布百分数达到50％时所对应的粒径。可采用本领域已知的方法和仪器测定。例如可以参照GB/T 19077-2016粒度分布激光衍射法，采用激光粒度分析仪测定。
复合正极材料的粒径过大不利于锂离子的嵌入和脱嵌，复合正极材料的粒径过小，材料容易聚集，复合正极材料的平均粒径在合适范围内使得电池能够发挥优异的电化学性能和循环性能。
在一些实施方式中，含锂的金属氧化物的通式如式II所示，
Li 1.05-a2M1 a2(Ni b2Co c2Mn d2) 1-e2Q e2O 2，式II
式中，0≤a2≤0.1，0.7≤b2≤0.96，0.03≤c2≤0.2，0.01≤d2≤0.2，0≤e2≤0.05；其中，M1选自碱金属元素Na、K、Rb、Cs中的一种或多种，Q选自Al、Mg、Zr、Ti、W、Y、B、Co、Nb、Mo、Sb、Sr中的一种或多种。
在一些实施方式中，0<a1≤0.1。在含锂的金属氧化物制备过程中，加入Na、K、Rb、Cs的碳酸盐、硫酸盐、氯化物或氧化物共烧结实现碱金属元素的掺杂。含锂的金属氧化物经过碱金属掺杂，可提高锂 离子扩散效率，进而保持电池的高容量和高倍率性能。
在一些实施方式中，0<e1≤0.05。在含锂的金属氧化物制备过程中，加入Al、Mg、Zr、Ti、W、Y、B、Co、Nb、Mo、Sb、Sr的氧化物、氢氧化物、碳酸盐或磷酸盐共烧结实现过渡金属元素的掺杂。过渡金属元素的掺杂可提高含锂的金属氧化物的结构稳定性，稳定结构骨架，进而提高电池的循环性能和高倍率性能。
含锂的金属氧化物含镍量高，具有高的能量密度，能够使得电池具有高的容量性能和功率性能。
在本申请的一个实施方式中，提供一种复合正极材料的制备方法，包括以下步骤：
将包含锂源、铁源、锰源、钒源、磷源和碳源的第一混合物进行第一烧结处理，制备碳复合的磷酸铁锰钒锂材料，
将包含锂源和镍钴锰前驱体的第二混合物进行第二烧结处理，锂源中的锂元素与镍钴锰前驱体中的镍元素、钴元素和锰元素总和的摩尔比为0.95～1.05，制备含锂的金属氧化物；
将碳复合的磷酸铁锰钒锂材料与含锂的金属氧化物进行第三烧结处理，得到复合正极材料，
复合正极材料包括含锂的金属氧化物以及设置在含锂的金属氧化物的至少一部分上的包覆层，包覆层为碳复合的磷酸铁锰钒锂材料，磷酸铁锰钒锂材料的通式如式I所示，
LiFe a1Mn b1V c1M2 d1PO 4，式I
其中，0.1≤a1≤0.8，0.1≤b1≤0.45，0.07≤c1≤0.3，0≤d1≤0.01，其中，M2选自Ni、Co、Ti、Al中的一种或多种。
在一些实施方式中，第三烧结处理的烧结温度为100～400℃。
在一些实施方式中，第三烧结处理的烧结时间为2～8h。
在一些实施方式中，第三烧结处理在还原气氛下进行，还原气氛为氮气或氩气。
通过上述方法制备的复合正极材料，碳复合的磷酸铁锰钒锂材料至少部分包覆含锂的金属氧化物，能够提高电池的循环性能、存储性 能以及安全性能，且电池的容量性能具有优良的保持率甚至能够得到进一步提升。
在一些实施方式中，在第三烧结处理中，含锂的金属氧化物与碳复合的磷酸铁锰钒锂材料与的质量比为9:1～999:1。
含锂的金属氧化物含量过低，电池的高容量性能难以保持，碳复合的磷酸铁锰钒锂材料含量过低，无法对含锂的金属氧化物形成有效包覆，循环性能和存储性能、安全性能的提升有限。
合适的包覆量能够兼顾电池的高容量性能与优异的循环性能、存储性能和安全性能。
在一些实施方式中，锂源为碳酸锂、氢氧化锂、磷酸锂、硝酸锂、醋酸锂中的一种或多种。在一些实施方式中，铁源为三氧化二铁、四氧化三铁中的一种或两种。在一些实施方式中，锰源为二氧化锰、四氧化三锰中的一种或两种。在一些实施方式中，钒源为三氧化二钒、五氧化二钒中的一种或两种。在一些实施方式中，磷源为磷酸铵、磷酸二氢铵、磷酸锂中的一种或多种。在一些实施方式中，碳源为炭黑、柠檬酸、聚乙二醇、蔗糖、葡萄糖中的一种或多种。
在一些实施方式中，将锂源、铁源、锰源、钒源、磷源和碳源混合，其中锂源中的锂金属元素的摩尔质量与铁源、锰源、钒源中铁元素、锰元素、钒元素的总摩尔质量比为0.95～1.05。
在一些实施方式中，包含锂源、铁源、锰源、钒源、磷源和碳源的第一混合物经过砂磨机细化并通过喷雾干燥后进行第一烧结处理。
碳复合的磷酸铁锰钒锂材料能够提高电池的循环性能、存储性能和安全性能。碳复合的磷酸铁锰钒锂材料中复合了碳元素，具有低的粉末电阻率，使得以其为包覆层的复合正极材料无需碳掺杂后处理，解决了常规碳包覆后处理所带来的不良效果，能够进一步提高正极复合材料的稳定性、降低制造成本。
在一些实施方式中，钒源中的钒元素与铁源中的铁元素的摩尔比为0.5:8～4:1。在一些实施方式中，钒源中的钒元素与铁源中的铁元素的摩尔比为1:8、1:7、1:6、1:5、1:4、1:3、1:2、1:1、2:1、3:1。
钒元素与铁元素的摩尔比过大，电池具有优异的倍率性能，然而电池的稳定性能下降。钒元素与铁元素的摩尔比过小，电池的稳定性能提升，然而电池的倍率性能下降。控制钒元素与铁元素的摩尔比，可以兼顾电池的倍率性能、循环性能与存储性能。
在一些实施方式中，碳源中碳元素的质量与磷酸铁锰钒锂材料的质量比为1:9999～1:4。在一些实施方式中，碳元素在碳复合的磷酸铁锰钒锂材料中的质量含量可以选自1:999、1:99、1:9、1:8、1:7、1:6、1:5。
在一些实施方式中，第一烧结处理的烧结温度为650℃～800℃，第一烧结处理的烧结时间为10～20h。
在一些实施方式中，第一烧结处理在还原气氛下进行。在一些实施方式中，第一烧结处理在氮气或氩气气氛下进行。
控制第一烧结处理的烧结时间可以控制碳复合的磷酸铁锰钒锂材料的成核生长过程。反应时间太短或反应温度过低容易导致碳复合的磷酸铁锰钒锂材料成核生长不完全、材料结晶性差。反应时间过长或反应温度过高容易导致碳复合的磷酸铁锰钒锂材料成核完成后会持续生长，造成碳复合的磷酸铁锰钒锂材料的粒径过大。
控制第一烧结处理的温度和时间在合适范围内有利于制备低粉末电阻率、合适平均粒径Dv50、适宜作为包覆层的碳复合的磷酸铁锰钒锂材料。
在一些实施方式中，第一混合物中还包含镍源、钴源、钛源，铝源中的一种或多种，所述镍源、钴源、钛源，铝源分别选自包含镍元素、钴元素、钛元素、铝元素的氧化物、氢氧化物、碳酸盐和磷酸盐的一种或多种。掺杂镍元素、钴元素、钛元素、铝元素提高碳复合的磷酸铁锰钒锂材料的稳定性，进一步提高电池的循环性能、存储性能和安全性能。
在一些实施方式中，第二烧结处理的烧结温度为600～900℃，烧结时间为10～20h。
在一些实施方式中，第二混合物中还包括碱金属化合物，碱金属 化合物的质量含量为0～5.5％，基于所述第二混合物的总质量计。
在一些实施方式中，碱金属化合物为Na、K、Rb、Cs的碳酸盐、硫酸盐、氯化物或氧化物。
在第二混合物中包括碱金属化合物，实现含锂的金属氧化物的碱金属掺杂，从而提高正极材料的锂离子扩散效率，进而优化电池的倍率性能，也能够提高电池的扣电首效。
本申请的一个实施方式中，提供一种二次电池。
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。
[正极极片]
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复合正极材料。
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。
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。
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。
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。
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，例如复合正极材料、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；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。
[负极极片]
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。
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。
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。
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。
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。
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。
在一些实施方式中，可以通过以下方式制备全电池的负极极片：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；将负极浆料涂覆在负极集流体上，经烘干、冷压等工序后，即可得到全电池的负极极片。
[电解质]
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。
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。
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。
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。
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。
[隔离膜]
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。
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。
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。
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。
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。
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3是作为一个示例的方形结构的二次电池5。
在一些实施方式中，参照图4，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。
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。
图5是作为一个示例的电池模块4。参照图5，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。
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。
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。
图6和图7是作为一个示例的电池包1。参照图6和图7，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。
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。
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。
图8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。
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。
实施例
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。
实施例1
复合正极材料的制备：
1)碳复合的磷酸铁锰钒锂材料的制备
第一烧结处理：将碳酸锂、三氧化二铁、二氧化锰、三氧化二钒、磷酸二氢铵按照摩尔比为1:0.5:0.4:0.2:2混合，按照混合物料质量的5％加入蔗糖，加入一定量水使得固含量在40％，经砂磨机研磨细化，打入搅拌罐中混合均匀，随后将混合均匀的浆料通过喷雾干燥得到混合粉末，物料放入窑炉中进行烧结，烧结温度为700℃，烧结时间为10h，烧结气氛为氮气，烧结得到碳复合的磷酸铁锰钒锂材料。
2)含锂的金属氧化物的制备
第二烧结处理：将氢氧化锂、正极材料前驱体Ni 0.8Co 0.1Mn 0.1(OH) 2、氧化铝按照摩尔比为1.05:0.99:0.01，置于犁刀混合机中混合均匀，随后将该混合的物料放入窑炉中烧结，烧结温度为750℃，烧结时间为15h，烧结气氛为氧气，冷却后，通过机械破碎得到含锂的金属氧化物。
3)复合正极材料的制备
第三烧结处理：将含锂的金属氧化物和碳复合的磷酸铁锰钒锂材料按95:5质量比混合均匀，在氮气气氛下，300℃下烧结5h，得到复合正极材料。
扣式电池的制备：
1)正极极片的制备
将复合正极材料、聚偏二氟乙烯(PVDF)、乙炔黑以90：5：5的重量比加入至溶剂N-甲基吡咯烷酮(NMP)中，在干燥房中搅拌制成浆料。在铝箔上涂覆上述浆料，干燥、冷压制成正极极片。涂覆量为0.01g/cm 2，压实密度为3.5g/cm 3。
2)负极极片的制备
将0.5mm锂金属片作为负极极片。
3)电解液的制备
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)体积比1:1:1混合，然后将LiPF 6均匀溶解在上述混合溶液中得到电解液，其中LiPF 6的浓度为1mol/L。
4)隔离膜的制备
隔离膜采购自Cellgard企业，型号为Cellgard 2400。
5)扣式电池的组装
将上述制备的正极极片、负极极片、隔离膜和电解液在扣电箱中组装成CR2032型扣式电池。
全电池的制备：
1)正极极片的制备
将复合正极材料、聚偏二氟乙烯(PVDF)、乙炔黑以90：5：5的重量比加入至溶剂N-甲基吡咯烷酮(NMP)中，在干燥房中搅拌制成浆料。在铝箔上涂覆上述浆料，干燥、冷压制成正极极片。涂覆量为0.01g/cm 2，压实密度为3.5g/cm 3。
2)负极极片的制备
将负极活性材料人造石墨、硬碳、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC)按照重量比90:5:2:2:1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0.015g/cm 2，压实密度为1.6g/cm 3。
3)电解液的制备
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)体积比1:1:1混合，然后将LiPF 6均匀溶解在上述混合溶液中得到电 解液，其中LiPF 6的浓度为1mol/L。
4)隔离膜的制备
以PE多孔聚合薄膜作为隔离膜。
5)全电池的制备
将上述正极极片、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，得到全电池(下文也称“全电”)。全电池的长×宽×高＝90mm×30mm×60mm，电池的群裕度为91.0％。实施例2～24的电池与实施例1的电池制备方法相似，
实施例2～5中通过改变第一烧结处理中加入的蔗糖的质量分数调整了碳复合的磷酸铁锰钒锂材料中碳的质量分数，实施例6-9中调整了第一烧结处理的温度，实施例10-13中调整了第一烧结处理的时间，实施例14～17中调整了包覆层的质量分数，实施例18-21中调整了第一烧结处理中钒源中的钒元素与铁源中的铁元素的摩尔比配比，具体参数如1所示。
实施例22中第二烧结处理中加入碳酸钠，氢氧化锂、碳酸钠、正极材料前驱体Ni 0.8Co 0.1Mn 0.1(OH) 2、氧化铝摩尔比为1.03:0.02:0.99:0.01。
实施例23中第一烧结处理中按照摩尔比为1:0.002:0.5:0.4:0.2:1加入氧化铝，碳酸锂、氧化铝、三氧化二铁、二氧化锰、三氧化二钒、磷酸二氢铵。
实施例24中第二烧结处理中加入的正极材料前驱体为Ni 0.92Co 0.06Mn 0.02(OH) 2。
对比例1中正极材料为含锂的金属氧化物，无包覆层；
对比例2中的包覆材料为碳复合的磷酸铁锰锂材料，具体参数如表1所示。
另外，将上述实施例1～24和对比例1、2中得到的碳复合的磷酸铁锰钒材料和电池进行性能测试，测试结果如表1所示。
测试方法如下：
1、 碳复合的磷酸铁锰钒材料的性能测试
1)碳复合的磷酸铁锰钒材料的粒径测试
参照GB/T 19077-2016粒度分布激光衍射法，采用激光粒度分析仪英国马尔文Mastersizer 2000E测定。
2)碳复合的磷酸铁锰钒材料的粉末电阻率
将碳复合的磷酸铁锰钒材料的粉末干燥，称取适量粉末，然后使用粉末电阻率测试仪，设备型号ST2722型数字式四探针仪，依据《锂离子电池用炭复合磷酸铁锂正极材料》GB/T 30835-2014测定样品的粉末电阻率。
3)碳复合的磷酸铁锰钒材料的碳含量测试
使用碳含量分析仪C content analyzer，设备型号HCS-140，依据钢铁总碳硫含量的测定使用高频感应炉燃烧后红外吸收法(常规方法)GBT20123-2006测试粉末中的碳含量。
2、复合正极材料的形貌表征
采用德国ZEISS公司的场发射扫描电子显微镜(Sigma300)表征复合正极材料的表面形貌。
3、电池的性能测试
1)扣式电池初始克容量及首效测试
在2.8～4.3V下，将扣式电池按照0.1C充电至4.3V，然后在4.3V下恒压充电至电流≤0.05mA，静置2min，此时的充电容量记为C0，然后按照0.1C放电至2.8V，此时的放电容量为初始克容量记为D0。首效按照D0/C0*100％计算得到。
2)25℃下全电池容量保持率
在25℃下，以1C的恒定电流充电至4.25V，后以4.25V恒压充电至电流降到0.05C，再以1C的恒定电流放电至2.8V，得首周放电比容量(Cd1)；如此反复充放电至第300周，得锂离子电池循环n周后的放电比容量记为Cdn。容量保持率＝循环n周后的 放电比容量(Cdn)/首周放电比容量(Cd1)。
3)45℃下全电池容量保持率
在45℃下，以1C的恒定电流充电至4.25V，后以4.25V恒压充电至电流降到0.05C，再以1C的恒定电流放电至2.8V，得首周放电比容量(Cd1)；如此反复充放电至第300周，得锂离子电池循环n周后的放电比容量记为Cdn。容量保持率＝循环n周后的放电比容量(Cdn)/首周放电比容量(Cd1)。
4)全电池70℃产气测试
在70℃下，存储100％充电状态(SOC)的全电池。在存储前后及过程中测量电芯的开路电压(OCV)和交流内阻(IMP)以监控SOC，并测量电芯的体积。其中在每存储48h后取出全电池，静置1h后测试OCV、IMP，并在冷却至室温后用排水法测量电芯体积。排水法即先用表盘数据自动进行单位转换的天平单独测量电芯的重力F1，然后将电芯完全置于去离子水(密度已知为1g/cm 3)中，测量此时的电芯的重力F 2，电芯受到的浮力F浮即为F 1-F 2，然后根据阿基米德原理F浮＝ρgV 排，计算得到电芯体积V＝(F 1-F 2)/ρg。
每次测试完体积后，对电芯进行补电，以1C的恒定电流充电至4.25V，后以4.25V恒压充电至电流降到0.05C，补电完成后入炉继续测试。
存储30天后，测量电芯体积，并计算相对于存储前的电芯体积，存储后的电芯体积增加量，即产气量，产气量/电芯容量即得单位容量产气体积。
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。
Figure PCTCN2022108009-appb-000001
Figure PCTCN2022108009-appb-000002
采用扫描电子显微镜SEM进行复合正极材料的形貌测试，测试结果见图1，通过图中明暗对比度可见，实施例1中制备的以Li 2FeMn 0.4V 0.4PO 4@C作为包覆层的复合正极材料粒径均匀，为微米级别，颗粒分布均匀，未发生团聚，以其为正极材料组装的电池的25℃循环性能测试曲线见图2，以此计算电池的循环容量保持率。
由实施例1～24以及对比例1的对比可以看出，本申请提供的复合正极材料包括：含锂的金属氧化物以及设置在含锂的金属氧化物的至少一部分上的包覆层，包覆层为碳复合的磷酸铁锰钒锂材料，磷酸铁锰钒锂材料的通式如式I所示，
LiFe a1Mn b1V c1M2 d1PO 4，式I
其中，0.1≤a1≤0.8，0.1≤b1≤0.45，0.07≤c1≤0.3，0≤d1≤0.01，其中，M2选自Ni、Co、Ti、Al中的一种或多种。
碳复合的磷酸铁锰钒锂材料包覆含锂的金属氧化物后制备的复合正极材料能够提高电池在常温和高温下的循环容量保持率、降低电池在高温下的单位容量产气体积，即，提高电池的循环性能、存储性能及安全性能，同时包覆层的包覆不会大幅度降低电池的容量性能，以复合正极材料作为正极的电池依然具有优异的容量性能和扣电首效。
由实施例1与对比例1～2的对比可见，相比于传统的磷酸锂铁锰包覆层，本申请的包覆层可以进一步提高电池的环性能、存储性能及安全性能，同时包覆层的包覆还能提高电池的克容量。
由实施例1、14～17可以看出，包覆层的质量含量为0.1％～10％，基于复合正极材料的总质量计时，复合正极材料在进一步提高了电池的循环性能、存储性能及安全性能的同时能够保持、甚至提高电池的容量性能和扣电首效。
由实施例1～5可以看出，包覆层中碳的质量分数为0.01％～25％，基于包覆层的总质量计时，包覆层具有合适的粉末电阻率，容易实现锂离子的脱嵌，即便在包覆层添加的情况下，电池的容量性能和首效 能够得到进一步保持或者提高，电池性能不会因包覆层的添加而恶化。
由实施例1～5和对比例3的对比可以看出，复合正极材料的粉末电阻率为1000～5500Ω·cm，复合正极材料的粉末电阻率低，材料稳定性和导电性更高，有助于电池容量的保持和提升。
由实施例1、6～13可以看出，复合正极材料的平均粒径D50为8-12μm，可选为8～10μm时，复合正极材料能够发挥优异的电化学性能和循环性能。
由实施例1、18～21可以看出，当钒源中的钒元素与铁源中的铁元素的摩尔比为0.5:8～4:1时，复合正极材料在进一步提高了电池的循环性能、存储性能及安全性能的同时能够保持、甚至提高电池的容量性能和扣电首效。
由实施例1、23可以看出，碳复合的磷酸铁锰钒锂材料中掺杂铝元素能够进一步提高包覆层的稳定性，进而提高电池在高温下的循环性能。
由实施例1、22可以看出，含锂的金属氧化物经过碱金属掺杂，电池的扣电首效、循环性能和存储性能均有所提升。
由实施例1、24可以看出，以碳复合的磷酸铁锰钒锂材料作为包覆层适用于不同镍钴锰含量的含锂金属氧化物，调节镍钴锰比例有助于调节电池的容量性能和扣电首效。

Claims (18)

  1. 一种复合正极材料，其特征在于，所述复合正极材料包括：含锂的金属氧化物以及设置在所述含锂的金属氧化物的至少一部分上的包覆层，所述包覆层为碳复合的磷酸铁锰钒锂材料，所述磷酸铁锰钒锂材料的通式如式I所示，
    LiFe a1Mn b1V c1M2 d1PO 4，式I
    其中，0.1≤a1≤0.8，0.1≤b1≤0.45，0.07≤c1≤0.3，0≤d1≤0.01，其中，M2选自Ni、Co、Ti、Al中的一种或多种。
  2. 根据权利要求1所述的复合正极材料，其特征在于，所述包覆层的质量含量为0.1％～10％，基于所述复合正极材料的总质量计。
  3. 根据权利要求1或2所述的复合正极材料，其特征在于，所述包覆层中碳的质量分数为0.01％～25％，基于所述包覆层的总质量计。
  4. 根据权利要求1至3中任一项所述的复合正极材料，其特征在于，所述复合正极材料的粉末电阻率为1000～5500Ω·cm。
  5. 根据权利要求1至4中任一项所述的复合正极材料，其特征在于，所述复合正极材料的平均粒径Dv50为8～12μm。
  6. 根据权利要求1至5中任一项所述的复合正极材料，其特征在于，所述含锂的金属氧化物的通式如式II所示，
    Li 1.05-a2M1 a2(Ni b2Co c2Mn d2) 1-e2Q e2O 2，式II
    式中，0≤a2≤0.1，0.7≤b2≤0.96，0.03≤c2≤0.2，0.01≤d2≤0.2，0≤e2≤0.05；其中，M1选自碱金属元素Na、K、Rb、Cs中的一种或多种，Q选自Al、Mg、Zr、Ti、W、Y、B、Co、Nb、Mo、Sb、Sr中的一种或多种。
  7. 一种复合正极材料的制备方法，其特征在于，包括以下步骤：
    将包含锂源、铁源、锰源、钒源、磷源和碳源的第一混合物进行第一烧结处理，制备碳复合的磷酸铁锰钒锂材料，
    将包含锂源和镍钴锰前驱体的第二混合物进行第二烧结处理，所述锂源中的锂元素与所述镍钴锰前驱体中的镍元素、钴元素和锰元素 总和的摩尔比为0.95～1.05，制备含锂的金属氧化物；
    将所述碳复合的磷酸铁锰钒锂材料与所述含锂的金属氧化物进行第三烧结处理，得到复合正极材料，
    所述复合正极材料包括含锂的金属氧化物以及设置在所述含锂的金属氧化物的至少一部分上的包覆层，所述包覆层为所述碳复合的磷酸铁锰钒锂材料，所述磷酸铁锰钒锂材料的通式如式I所示，
    LiFe a1Mn b1V c1M2 d1PO 4，式I
    其中，0.1≤a1≤0.8，0.1≤b1≤0.45，0.07≤c1≤0.3，0≤d1≤0.01，其中，M2选自Ni、Co、Ti、Al中的一种或多种。
  8. 根据权利要求7所述的复合正极材料的制备方法，其特征在于，在所述第三烧结处理中，所述含锂的金属氧化物与所述碳复合的磷酸铁锰钒锂材料与的质量比为9:1～999:1。
  9. 根据权利要求7或8所述的复合正极材料的制备方法，其特征在于，在所述第一烧结处理中，所述钒源中的钒元素与所述铁源中的铁元素的摩尔比为0.5:8～4:1。
  10. 根据权利要求7至9中任一项所述的复合正极材料的制备方法，其特征在于，所述碳源中碳元素的质量与所述磷酸铁锰钒锂材料的质量比为1:9999～1:4。
  11. 根据权利要求7至10中任一项所述的复合正极材料的制备方法，其特征在于，所述第一烧结处理的烧结温度为650℃～800℃，或所述第一烧结处理的烧结时间为10～20h。
  12. 根据权利要求7至11中任一项所述的复合正极材料的制备方法，其特征在于，所述第一混合物中还包含镍源、钴源、钛源，铝源中的一种或多种，所述镍源、钴源、钛源，铝源分别选自包含镍元素、钴元素、钛元素、铝元素的氧化物、氢氧化物、碳酸盐和磷酸盐的一种或多种。
  13. 根据权利要求7至12中任一项所述的复合正极材料的制备方法，其特征在于，所述铁源选自三氧化二铁和四氧化三铁中的一种或多种；所述锰源选自二氧化锰和四氧化三锰中的一种或多种；所述 钒源选自三氧化二钒和五氧化二钒中的一种或多种；所述磷源选自磷酸铵、磷酸二氢铵、磷酸锂中的一种或多种；所述碳源选自炭黑、柠檬酸、聚乙二醇、蔗糖、葡萄糖中的一种或多种。
  14. 根据权利要求7至13中任一项所述的复合正极材料的制备方法，其特征在于，还包括以下步骤：
    所述第二混合物中还包括碱金属化合物，所述碱金属化合物的质量含量为0～5.5％，基于所述第二混合物的总质量计。
  15. 一种二次电池，包括正极极片、隔离膜、负极极片以及电解液，所述正极极片包括权利要求1至6中任一项所述的复合正极材料。
  16. 一种电池模块，其特征在于，包括权利要求15所述的二次电池。
  17. 一种电池包，其特征在于，包括权利要求16所述的电池模块。
  18. 一种用电装置，其特征在于，包括选自权利要求15所述的二次电池、权利要求16所述的电池模块或权利要求17所述的电池包中的至少一种。
PCT/CN2022/108009 2022-07-26 2022-07-26 一种复合正极材料、其制备方法、二次电池、电池模块、电池包和用电装置 WO2024020795A1 (zh)

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