WO2022134540A1 - 正极材料、电化学装置和电子装置 - Google Patents

正极材料、电化学装置和电子装置 Download PDF

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WO2022134540A1
WO2022134540A1 PCT/CN2021/104957 CN2021104957W WO2022134540A1 WO 2022134540 A1 WO2022134540 A1 WO 2022134540A1 CN 2021104957 W CN2021104957 W CN 2021104957W WO 2022134540 A1 WO2022134540 A1 WO 2022134540A1
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positive electrode
electrode material
particles
satisfies
particle size
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PCT/CN2021/104957
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English (en)
French (fr)
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刘文元
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宁德新能源科技有限公司
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Priority to EP21908545.3A priority Critical patent/EP4254556A1/en
Publication of WO2022134540A1 publication Critical patent/WO2022134540A1/zh
Priority to US18/341,099 priority patent/US20230335731A1/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
    • 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
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/40—Nickelates
    • C01G53/42—Nickelates containing alkali metals, e.g. LiNiO2
    • C01G53/44—Nickelates containing alkali metals, e.g. LiNiO2 containing manganese
    • C01G53/50—Nickelates containing alkali metals, e.g. LiNiO2 containing manganese of the type [MnO2]n-, e.g. Li(NixMn1-x)O2, Li(MyNixMn1-x-y)O2
    • 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
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/46—Separators, membranes or diaphragms characterised by their combination with electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the technical field of electrochemistry, and in particular, to a positive electrode material, an electrochemical device, and an electronic device.
  • Electrochemical devices such as lithium-ion batteries
  • electrochemical devices are widely used in various fields. With the progress of society, people have put forward higher requirements for the cycle performance and rate performance of electrochemical devices.
  • the particle size of the positive electrode material is reduced to improve the rate capability of the electrochemical device.
  • cathode materials with small particle size have poor processing performance, are prone to self-agglomeration, easily generate particles and bubbles during coating, and are prone to uneven weight distribution during high-speed coating, resulting in electrochemical The polarization of the device increases, and local lithium precipitation is prone to occur, which affects the cycle performance and rate performance of the electrochemical device.
  • This application proposes a positive electrode material, the positive electrode material contains at least one of Al element or Zr element; the positive electrode material particles satisfy 0.01 ⁇ ( Dv99a - Dv99b ) /Dv99b ⁇ 0.5 ; Dv99a and Dv99b are respectively Dv99 values of positive electrode material particles measured before and after ultrasonication.
  • the positive electrode material particles satisfy: 0.01 ⁇ (Dv50a- Dv50b ) /Dv50b ⁇ 0.30 ;
  • Dv50a and Dv50b are the Dv50 values of the positive electrode material particles measured before and after ultrasonic treatment, respectively .
  • the cathode material satisfies at least one of the following conditions (a) to (d):
  • Dv50 a satisfies: 2 ⁇ m ⁇ Dv50a ⁇ 17 ⁇ m ;
  • the positive electrode material contains primary particles, and the average value A of the particle diameters of the primary particles satisfies: 200 nm ⁇ A ⁇ 4 ⁇ m.
  • the cathode material satisfies at least one of the following conditions (e) to (i):
  • Dv50 a satisfies: 3 ⁇ m ⁇ Dv50 a ⁇ 6 ⁇ m;
  • the specific surface area BET of the positive electrode material satisfies: 0.5m 2 /g ⁇ BET ⁇ 0.8m 2 /g;
  • the positive electrode material contains primary particles, and the average value A of the primary particle size satisfies: 1 ⁇ m ⁇ A ⁇ 4 ⁇ m;
  • the mass ratio of the Al element to the cathode material is 0.05% to 0.5%.
  • the positive electrode material includes first particles and second particles, the first particle size is D1, the second particle size is D2, and D2 ⁇ D1.
  • the first particles and the second particles satisfy at least one of the following conditions (j) to (k):
  • Dv50 a1 and Dv50 b1 are the Dv50 values of the first particles measured before and after ultrasonic treatment, respectively, and Dv99 a1 and Dv99 b1 are the Dv99 values of the first particles measured before and after ultrasonic treatment, respectively.
  • the second particles satisfy at least one of the following conditions (l) to (m)
  • Dv50 a2 and Dv50 b2 are the Dv50 values of the second particles measured before and after ultrasonic treatment, respectively, and Dv99 a2 and Dv99 b2 are the Dv99 values of the second particles measured before and after ultrasonic treatment, respectively.
  • the first particle and the second particle satisfy at least one of conditions (n) to (p):
  • Dv50 a1 and Dv50 a2 are the Dv50 values of the first particle and the second particle measured before ultrasonication, respectively.
  • the first particles include primary particles, and the average value A 1 of the particle diameters of the primary particles in the first particles satisfies: 300 nm ⁇ A 1 ⁇ 800 nm; and/or, the second particles include primary particles, the second The average value A 2 of the particle diameters of the primary particles among the particles satisfies: 0.2 ⁇ m ⁇ A 2 ⁇ 4 ⁇ m.
  • the present application also proposes an electrochemical device, comprising:
  • the present application also provides an electronic device, including the above electrochemical device.
  • the present application proposes a positive electrode material, an electrochemical device and an electronic device, wherein the positive electrode material contains at least one of Al element or Zr element; the positive electrode material particles satisfy 0.01 ⁇ ( Dv99a - Dv99b ) /Dv99b ⁇ 0.5 ; Dv99 a and Dv99 b are the Dv99 values of the positive electrode material particles measured before and after ultrasonic treatment, respectively.
  • the cathode material proposed in this application can improve the processability of the cathode material and the cycle performance of the electrochemical device.
  • the small particle positive electrode material has poor processing performance, and is prone to self-agglomeration, causing problems such as particles or bubbles during coating, and in high-speed coating.
  • the problem of uneven weight distribution is easy to occur during the cloth, which causes the polarization of the electrochemical device to increase, and lithium precipitation occurs, which affects the cycle performance and rate performance of the electrochemical device, and leads to a significant temperature rise of the electrochemical device.
  • a positive electrode material is proposed in some embodiments of the present application.
  • the positive electrode material contains at least one of Al element or Zr element; the positive electrode material particles satisfy 0.01 ⁇ ( Dv99a - Dv99b )/ Dv99b ⁇ 0.5 .
  • Dv99 a and Dv99 b are the Dv99 values of the positive electrode material particles measured before and after ultrasonic treatment, respectively.
  • the positive electrode material includes positive electrode material particles, and the positive electrode material may be, for example, a lithium cobalt oxide material containing at least one of Al element or Zr element.
  • Zr may be doped in the cathode material.
  • the present application can improve the processing performance of the positive electrode material by controlling 0.01 ⁇ ( Dv99a - Dv99b ) /Dv99b ⁇ 0.5 , and prevent the electrochemical device using the positive electrode material. Lithium is precipitated, and the cycle performance of the electrochemical device is guaranteed and the temperature rise is reduced.
  • the particle size before and after ultrasonication is analyzed by a Mastersizer 3000 laser particle size distribution tester.
  • the laser particle size test measures the particle size distribution based on the principle that particles of different sizes can scatter laser light with different intensities.
  • Dv50 represents the particle size that reaches 50% of the cumulative volume from the small particle size side in the particle size distribution based on volume.
  • Dv99 represents the particle size that reaches 99% of the cumulative volume from the small particle size side in the particle size distribution based on volume.
  • the following method can be used to obtain the positive electrode material in the electrochemical device in a dry room with 2% relative humidity. After discharge, the electrochemical device was disassembled to obtain the positive electrode. After soaking the positive electrode in NMP (N-methylpyrrolidone) solution for 24 hours, it was calcined at 650°C for 5 hours in an air atmosphere, and the active material layer on the positive electrode was scraped off. The obtained positive electrode material powder is ground evenly, passes through a 400-mesh sieve, and the powder that passes through the 400-mesh sieve is collected, which is a positive electrode material.
  • NMP N-methylpyrrolidone
  • the positive electrode material particles satisfy: 0.01 ⁇ (Dv50a- Dv50b ) /Dv50b ⁇ 0.30 ;
  • Dv50a and Dv50b are the Dv50 values of the positive electrode material particles measured before and after ultrasonic treatment, respectively .
  • the Dv50 of the positive electrode material particles measured before and after ultrasonic treatment has little change, so it can be known that the self-aggregation of the positive electrode material particles is relatively light or has almost no self-aggregation, which is beneficial to improve the use of this method.
  • Dv50 a satisfies: 2 ⁇ m ⁇ Dv50 a ⁇ 17 ⁇ m, and in some embodiments, Dv50 a satisfies: 3 ⁇ m ⁇ Dv50 a ⁇ 6 ⁇ m.
  • Dv99 a satisfies: 6 ⁇ m ⁇ Dv99 a ⁇ 40 ⁇ m, and in some embodiments, Dv99 a satisfies: 8 ⁇ m ⁇ Dv99 a ⁇ 30 ⁇ m.
  • the particle size of the positive electrode material particle affects the cycle performance and temperature rise of the electrochemical device using the positive electrode material, the smaller the particle size of the positive electrode material particle, the smaller the cycle capacity retention rate of the electrochemical device and the temperature rise, Therefore, in some embodiments, the minimum values of Dv50 a and Dv99 a of the positive electrode material particles are limited. On the other hand, when the particle size of the positive electrode material particles is large, the rate performance will be affected. Therefore, in some embodiments, the maximum values of Dv50 a and Dv99 a are limited. value.
  • the specific surface area BET of the positive electrode material satisfies: 0.1m 2 /g ⁇ BET ⁇ 0.9m 2 /g, and in some embodiments, the specific surface area BET of the positive electrode material satisfies: 0.5m 2 /g ⁇ BET ⁇ 0.8 m 2 /g. In some embodiments, if the specific surface area of the positive electrode material is too small, the rate performance will be poor, and when the specific surface area of the positive electrode material is too large, the electrolyte consumption of the electrochemical device using the positive electrode material will increase.
  • the positive electrode material contains primary particles, and the average value A of the primary particle size satisfies: 200nm ⁇ A ⁇ 4 ⁇ m, in some embodiments, the positive electrode material contains primary particles, and the average value A of the primary particle size satisfies : 1 ⁇ m ⁇ A ⁇ 4 ⁇ m.
  • increasing the average value A of the primary particle size is beneficial to improve the cycle performance of the electrochemical device using the positive electrode material, so the minimum value of A is limited.
  • the average value A of the primary particle size is too large , the temperature rise of the electrochemical device using this cathode material will increase, and the kinetic performance will be deteriorated, so the maximum value of A is limited.
  • some particle sizes of the positive electrode material are tested by a scanning electron microscope, and after the positive electrode material of the present application is imaged by a scanning electron microscope (ZEISS Sigma-02-33, Germany) at a magnification of 500 times, random particles are randomly selected in the electron microscope image. 200 to 600 primary particles of positive electrode material with complete shape and no shielding are selected, and the average value of the longest diameter of the primary particles in the microscopic image is recorded as the average particle size.
  • ZEISS Sigma-02-33, Germany scanning electron microscope
  • the mass ratio of Al element to the cathode material is 0.05% to 0.5%.
  • the positive electrode material includes first particles and second particles, the first particle size is D1, the second particle size is D2, and D2 ⁇ D1.
  • Taylor sieve system is used in some embodiments of the present application.
  • the first particles and the second particles are obtained by the following methods, a part of the positive electrode material is taken in a drying room with a relative humidity of 2%, uniformly dispersed in the NMP solution, and after ultrasonic dispersion for 12 hours, stirring is uniform to obtain a suspension, The suspension was slowly poured into a 1500-mesh sieve while stirring, and a part of the small particles entered the filtrate through the sieve.
  • the powder obtained after drying was The second particle in the present application; a part of the large particles is on the screen, and the powder obtained after drying is the first particle in the present application.
  • the first particles and the second particles satisfy: 0.01 ⁇ (Dv50 a1 ⁇ Dv50 b1 )/Dv50 b1 ⁇ 0.1. In some embodiments, the first particles and the second particles satisfy: 0.01 ⁇ Dv99 a1 ⁇ Dv99 b1 )/Dv99 b1 ⁇ 0.25.
  • Dv50 a1 and Dv50 b1 are the Dv50 values of the first particles measured before and after ultrasonic treatment, respectively
  • Dv99 a1 and Dv99 b1 are the Dv99 values of the first particles measured before and after ultrasonic treatment, respectively.
  • the second particles satisfy: 0.05 ⁇ (Dv50 a2 ⁇ Dv50 b2 )/Dv50 b2 ⁇ 0.3. In some embodiments, the second particle satisfies: 0.2 ⁇ (Dv99 a2 ⁇ Dv99 b2 )/Dv99 b2 ⁇ 1.
  • Dv50 a2 and Dv50 b2 are the Dv50 values of the second particles measured before and after ultrasonic treatment, respectively, and Dv99 a2 and Dv99 b2 are the Dv99 values of the second particles measured before and after ultrasonic treatment, respectively.
  • the first particles and the second particles when the first particles and the second particles satisfy the above-mentioned conditions, it indicates that the first particles and the second particles rarely agglomerate, thereby helping to improve the processability of the positive electrode material and preventing electrochemical devices using the positive electrode material. Lithium precipitation problem occurs.
  • the first particles and the second particles satisfy: 7 ⁇ m ⁇ Dv50 a1 ⁇ 15 ⁇ m.
  • the first particles and the second particles satisfy: 2 ⁇ m ⁇ Dv50 a2 ⁇ 8 ⁇ m.
  • the first particles and the second particles satisfy: 1.5 ⁇ Dv50 a1 /Dv50 a2 ⁇ 5.5.
  • Dv50 a1 and Dv50 a2 are the Dv50 values of the first particle and the second particle measured before ultrasonication, respectively.
  • the positive electrode active layer when the Dv50s of the first particles and the second particles satisfy the above conditions, the positive electrode active layer has a better compaction density, which improves the energy density of the electrochemical device.
  • the first particles include primary particles, and the average value A 1 of the particle diameters of the primary particles in the first particles satisfies: 300 nm ⁇ A 1 ⁇ 800 nm.
  • the first particles include primary particles, and the average value A 1 of the particle diameters of the primary particles in the first particles satisfies: 500 nm ⁇ A 1 ⁇ 800 nm.
  • the second particles include primary particles, and the average value A 2 of the particle diameters of the primary particles in the second particles satisfies: 0.2 ⁇ m ⁇ A 2 ⁇ 4 ⁇ m.
  • the electrochemical device when the average value of the particle diameters of the primary particles of at least one of the first particles or the second particles satisfies the above conditions, the electrochemical device has balanced cycle performance and safety performance.
  • the present application also proposes an electrochemical device, comprising: a positive electrode, a negative electrode and a separator.
  • the positive electrode of the above electrochemical device includes a positive electrode current collector and a positive electrode material disposed on the positive electrode current collector.
  • the positive electrode material may be any of the above positive electrode materials.
  • the positive electrode material includes a positive electrode material capable of absorbing and releasing lithium (Li).
  • cathode materials capable of absorbing/releasing lithium (Li) may include lithium cobalt oxide, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium manganate, lithium iron manganese phosphate, lithium vanadium phosphate, lithium vanadyl phosphate, phosphoric acid Lithium iron, lithium titanate, and lithium-rich manganese-based materials.
  • the chemical formula of lithium cobalt oxide can be as chemical formula 1:
  • M1 represents selected from nickel (Ni), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), Copper (Cu), Zinc (Zn), Molybdenum (Mo), Tin (Sn), Calcium (Ca), Strontium (Sr), Tungsten (W), Yttrium (Y), Lanthanum (La), Zirconium (Zr) and At least one of silicon (Si), the values of x, a, b and c are respectively in the following ranges: 0.8 ⁇ x ⁇ 1.2, 0.8 ⁇ a ⁇ 1, 0 ⁇ b ⁇ 0.2, -0.1 ⁇ c ⁇ 0.2.
  • nickel cobalt lithium manganate or nickel cobalt aluminate can be as chemical formula 2:
  • M2 represents selected from cobalt (Co), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), at least one of copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), tungsten (W), zirconium (Zr) and silicon (Si),
  • the values of y, d, e and f are respectively in the following ranges: 0.8 ⁇ y ⁇ 1.2, 0.3 ⁇ d ⁇ 0.98, 0.02 ⁇ e ⁇ 0.7, -0.1 ⁇ f ⁇ 0.2.
  • the chemical formula of lithium manganate can be as chemical formula 3:
  • M3 represents selected from cobalt (Co), nickel (Ni), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), At least one of copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W), with z, g and h values in the following ranges, respectively Inside: 0.8 ⁇ z ⁇ 1.2, 0 ⁇ g ⁇ 1.0 and -0.2 ⁇ h ⁇ 0.2.
  • a conductive agent or a positive electrode binder may be added to the positive electrode of the above electrochemical device.
  • the positive electrode further includes a carbon material, and the carbon material may include conductive carbon black, graphite, graphite At least one of olefins, carbon nanotubes, carbon fibers or carbon black.
  • the positive electrode binder may include polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, styrene-acrylate copolymer, styrene-butadiene copolymer, polyamide, polyacrylonitrile, polyacrylate, At least one of polyacrylic acid, polyacrylate, sodium carboxymethyl cellulose, polyvinyl acetate, polyethylene pyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene or polyhexafluoropropylene kind.
  • the negative electrode includes a negative electrode current collector and a negative electrode material.
  • the negative electrode material is located on the negative electrode current collector.
  • the negative electrode current collector may include at least one of copper foil, aluminum foil, nickel foil, or fluorocarbon current collector.
  • the negative electrode material further includes a negative electrode conductive agent and/or a negative electrode binder.
  • the negative electrode binder may include carboxymethyl cellulose (CMC), polyacrylic acid, polyvinylpyrrolidone, polyaniline, polyimide, polyamideimide, polysiloxane, polybutylene At least one of styrene rubber, epoxy resin, polyester resin, polyurethane resin or polyfluorene.
  • the mass percentage of the negative electrode binder in the negative electrode material is 0.5% to 10%.
  • the negative electrode conductive agent may include at least one of conductive carbon black, ketjen black, acetylene black, carbon nanotube, VGCF (Vapor Grown Carbon Fiber, vapor grown carbon fiber) or graphene.
  • the release membrane includes at least one of polyethylene, polypropylene, polyvinylidene fluoride, polyethylene terephthalate, polyimide, or aramid.
  • the polyethylene includes at least one selected from high density polyethylene, low density polyethylene or ultra-high molecular weight polyethylene. Especially polyethylene and polypropylene, they have a good effect on preventing short circuits and can improve the stability of the battery through the shutdown effect.
  • the present application also provides an electronic device, including the electrochemical device according to any one of the above.
  • the electronic device of the present application is not particularly limited, and it can be used in any electronic device known in the prior art.
  • electronic devices may include, but are not limited to, notebook computers, pen input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, headsets, VCRs, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, assisted bicycles, bicycles, Lighting equipment, toys, game consoles, clocks, power tools, flashlights, cameras and large batteries for household use, etc.
  • electronic devices include cell phones that contain lithium-ion batteries.
  • the molar ratio was mixed, and the primary substance was obtained after sintering at a primary sintering temperature of 820° C. for 16 hours, and after washing and drying with water.
  • the primary material was crushed, and the crushing pressure was 0.4MPa.
  • After washing with water, it was mixed with Al(OH) 3 uniformly according to the mass ratio of Al/(Ni+Co+Mn) 0.001, and sintered at 600°C for 6h.
  • a positive electrode material is obtained, and the parameters of the positive electrode material obtained at this time are shown in the data of Example 1 in Table 2.
  • Positive electrode preparation mix the positive electrode material, the conductive agent Super P, and the binder polyvinylidene fluoride according to the weight ratio of 97.9:0.4:1.7, add N-methylpyrrolidone (NMP), and stir uniformly under the action of a vacuum mixer to obtain Positive electrode slurry; the positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector aluminum foil; after drying, cold pressing, cutting and slitting, and drying under vacuum conditions, the positive electrode is obtained.
  • NMP N-methylpyrrolidone
  • Negative electrode preparation The negative electrode active material artificial graphite, the thickener sodium carboxymethyl cellulose, and the binder styrene-butadiene rubber are mixed according to the weight ratio of 97:1:2, deionized water is added, and the negative electrode slurry is obtained under the action of a vacuum mixer The negative electrode slurry is uniformly coated on both surfaces of the negative electrode current collector copper foil, after drying, cold pressing, cutting and slitting, and drying under vacuum conditions to obtain a negative electrode.
  • Electrolyte preparation In a dry argon atmosphere glove box, ethylene carbonate, propylene carbonate and dimethyl carbonate are uniformly mixed in a ratio of 2:2:6, and lithium salt LiPF 6 is added to make the final electrolyte obtained.
  • the lithium salt concentration is 1.10 mol/L; 1% of vinylene carbonate is added based on the total weight of the electrolyte, and the mixture is uniformly mixed to obtain the electrolyte.
  • Battery preparation Using the polyethylene porous polymer film as the separator, stack the positive electrode, separator and negative electrode in sequence, so that the separator is placed between the positive electrode and the negative electrode for isolation, and the electrode assembly is obtained by winding.
  • the electrode assembly is placed in the outer packaging aluminum-plastic film, injected with electrolyte and packaged, and the lithium ion battery is obtained through the process of formation, degassing, and trimming.
  • Example 1 The difference between Examples 2 to 12 and Example 1 is that at least one of the Span of the precursor, the BET of the precursor, the Dv50 a3 of the precursor and the primary sintering temperature during the preparation of the positive electrode material are different.
  • the specific parameters are shown in the table 1.
  • Example 13 The difference between Example 13 and Example 1 is that the preparation method of the positive electrode material is different.
  • the preparation method of the positive electrode material adopted in Example 13 is as follows:
  • Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 precursor was prepared by batch co-precipitation, the Span was 0.65, the BET was 16 m 2 / g , and the Dv50 a3 was 4.5 ⁇ m.
  • the primary material is crushed, and the crushing pressure is 0.6MPa.
  • the positive electrode material is obtained after sieving through the upper layer 254 mesh and the lower layer 325 mesh double-layer vibrating screen.
  • Examples 14 to 16 differ from Example 13 in that at least one of the primary sintering temperature and the doping content are different when preparing the positive electrode material.
  • the specific parameters are shown in Table 3.
  • Examples 17 to 35 The difference between Examples 17 to 35 and Example 1 is that the positive electrode materials used in Examples 17 to 35 are obtained by mixing any two positive electrode materials from Examples 1 to 16. For specific parameters, see table 5.
  • Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the preparation method of the positive electrode material is different.
  • the preparation method of the positive electrode material adopted in Comparative Example 1 is as follows:
  • the Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 precursor was prepared by the continuous co-precipitation method to obtain a precursor with a Span of 1.1, a BET of 18 m 2 /g, and a Dv50 a3 of 4.5 ⁇ m.
  • Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the preparation method of the positive electrode material is different.
  • the preparation method of the positive electrode material adopted in Comparative Example 2 is as follows:
  • Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 precursor was prepared by the continuous co-precipitation method to obtain a precursor with a Span of 1.1, a BET of 22 m 2 /g, and a Dv50 a3 of 4.5 ⁇ m.
  • Ni+Co+Mn) 1.03 molar ratio to mix, sintering at a primary sintering temperature of 870° C. for 16 hours, and after washing and drying with water, the primary substance is obtained.
  • the lithium ion batteries prepared in the examples and comparative examples were tested according to the following methods:
  • Determination of the particle size of the positive electrode material before and after ultrasonication The particle size before and after ultrasonication was analyzed by a Mastersizer 3000 laser particle size distribution tester.
  • the laser particle size test measures the particle size distribution based on the principle that particles of different sizes can scatter laser light with different intensities.
  • Dv50 represents the particle size that reaches 50% of the cumulative volume from the small particle size side in the particle size distribution based on volume.
  • Dv99 represents the particle size that reaches 99% of the cumulative volume from the small particle size side in the particle size distribution based on volume.
  • the other test conditions should be exactly the same except for the ultrasonic pretreatment.
  • the dispersant is water, the dispersion method adopts external ultrasonic, the ultrasonic time is 5min, the ultrasonic intensity is 40KHz 180w, and the sampling operation is all sampling.
  • Measurement of primary particle size After imaging the positive electrode materials of the examples and comparative examples through a scanning electron microscope (ZEISS Sigma-02-33, Germany) at a magnification of 500, randomly select 200 to 600 complete shapes in the electron microscope images. And the primary particles of the positive electrode material without shielding, and the average value of the longest diameter of the primary particles in the microscopic image is recorded as the average particle size.
  • ZEISS Sigma-02-33, Germany scanning electron microscope
  • Cycle performance test The lithium-ion batteries of the following examples and comparative examples were placed in an incubator at 45°C ⁇ 2°C for 2 hours, charged to 4.25V with a constant current of 1.5C, and then charged to a constant voltage of 4.25V to 0.02 C and stand for 15 minutes; then discharge to 2.8V with a constant current of 4.0C, this is a charge-discharge cycle process, record the discharge capacity of the lithium-ion battery for the first cycle; then repeat the charge-discharge cycle process 500 times according to the above method, And the discharge capacity of the 500th cycle was recorded.
  • the cycle capacity retention rate of the lithium ion battery discharge capacity at the 500th cycle (mAh)/discharge capacity after the first cycle (mAh) ⁇ 100%.
  • Determination of the degree of lithium precipitation after the cycle Charge the battery after the cycle to 4.25V at a constant current of 1.5C, disassemble the battery, and when the negative electrode as a whole shows golden yellow and the gray area is less than 2%, it is judged that no lithium precipitation ; When most of the negative electrode is golden yellow, but gray can be observed in some places, and the gray area is between 2% and 20%, it is judged as slight lithium precipitation; when the negative electrode is gray, but some golden yellow can still be observed , the gray area is between 20% and 60%, it is judged as moderate lithium precipitation; when most of the negative electrode is gray, and the gray area is greater than 60%, it is judged as severe lithium precipitation.
  • Temperature rise test The lithium-ion batteries of the examples and comparative examples were placed in a constant temperature box at 25°C ⁇ 2°C for 2 hours, charged with a constant current of 1.5C to 4.25V, and then charged with a constant voltage of 4.25V to 0.02C And let stand for 15 minutes; then discharge to 2.8V with 10C constant current, this is a charge-discharge cycle process, so cycle again, test the surface temperature of the lithium-ion battery at this time, minus the initial temperature of the lithium-ion battery is temperature rise.
  • the filterability of the slurry refers to the time it takes to pass 400mL of the positive electrode slurry through a 300-mesh screen, in seconds. The shorter the time, the better the filterability of the slurry.
  • Separation of the first particles and the second particles take a part of the positive electrode material in a drying room with 2% relative humidity, disperse it in the NMP solution uniformly, and after ultrasonic dispersion for 12 hours, stir evenly to obtain a suspension containing the positive electrode material.
  • the suspension was slowly poured into a 1500-mesh sieve while stirring, and a part of the small particles entered the filtrate through the sieve. After the filtrate was allowed to stand for 24 hours, the supernatant was poured out, and the powder obtained after drying was the first The second particle, the other part of the large particle is on the screen, and the powder obtained after drying is the first particle.
  • the ( Dv99a - Dv99b )/ Dv99b of the positive electrode material was adjusted by controlling the Span, BET, primary sintering temperature and pulverization gas pressure of the precursor.
  • the decrease of sintering temperature will cause the decrease of Dv50a to a certain extent; the higher the Span of the precursor, the smaller the BET of the precursor, the lower the primary sintering temperature, and the lower the pulverization pressure, the higher the Span of the precursor, the lower the primary sintering temperature, and the lower the pulverization pressure.
  • the cycle capacity retention rate of Comparative Example 1 is the lowest, because the cycle capacity retention rate is mainly affected by the particle size, the larger the particle size, the higher the cycle capacity retention rate .
  • Example 13 to 16 The parameters of the preparation methods of the positive electrode materials from Examples 13 to 16 are shown in Table 3, and the performance test results are shown in Table 4.
  • the primary sintering temperature, doping elements and contents were adjusted by adjusting and sieving method to adjust the size of ( Dv99a - Dv99b )/ Dv99b and ( Dv50a - Dv50b )/ Dv50b of the positive electrode material, and also adjust the size of primary particles.
  • Example 13 to Example 16 Comparing Example 13 to Example 16 with Example 1 to Example 12, it can be seen that the cycle capacity retention rate of Example 13 to Example 16 is significantly increased, which is mainly because in Example 13 to Example 16
  • the particle size of the primary particle is increased to more than 1 ⁇ m, and the particle size of the primary particle (the primary particle size of the positive electrode material) has better large cycle performance.
  • Examples 13 to 15 in Table 3 that by increasing the primary sintering The temperature can increase the particle size of the primary particles.
  • the particle size of the primary particles can also be increased by adding some doping elements that can be fluxed, such as Zr elements.
  • the average value A of the primary particle diameter of the positive electrode material is defined to be not less than 1 ⁇ m.
  • the average value A of the primary particle size of the positive electrode material is limited to be no greater than 4 ⁇ m.
  • Example 17 to 35 any two positive electrode materials from Examples 1 to 16 were mixed, and the mixing ratios are shown in Table 5.
  • the physical parameters of Examples 17 to 35 are shown in Table 6, and Table 7 shows the performance test results.
  • the particle size of the first positive electrode material is larger than the particle size of the second positive electrode material.
  • Examples 17 to 27 use a combination of large-particle polycrystals and small-particle polycrystals, and Examples 28 to 35 use large-particle polycrystals.
  • the combination of particle polycrystalline and small particle single crystal, different mass ratios were used in Example 32 to Example 35. It can be seen from Table 7 that after the cycle, Example 15 to Example 35 using various mixing methods did not. Lithium precipitation occurs, and the cycle capacity retention rate is good.
  • the lithium ion battery will not have lithium precipitation, and can maintain a good cycle capacity retention rate.

Abstract

本申请提出一种正极材料、电化学装置和电子装置，其中正极材料中含有Al元素或Zr元素中的至少一种；正极材料颗粒满足0.01≤(Dv99 a－Dv99 b)/Dv99 b≤0.5；Dv99 a和Dv99 b分别为超声波处理前和超声波处理后测得的正极材料颗粒的Dv99的值。本申请提出的正极材料能够改善正极材料的加工性能和电化学装置的循环性能。

Description

正极材料、电化学装置和电子装置
相关申请的交叉引用
本申请基于申请号为202011560549.8、申请日为2020年12月25日，名称为“正极材料、电化学装置和电子装置”的中国专利申请提出，并要求该中国专利申请的优先权，该中国专利申请的全部内容在此引入本申请作为参考。
技术领域
本申请涉及电化学技术领域，尤其涉及一种正极材料、电化学装置和电子装置。
背景技术
电化学装置(例如锂离子电池)被广泛使用在各个领域，随着社会的进步，人们对于电化学装置的循环性能和倍率性能提出了更高要求。
一些技术中通过减小正极材料的粒径以提高电化学装置的倍率性能。然而，小粒径的正极材料的加工性能差，较为容易发生自团聚，在涂布时极易产生颗粒和气泡，且在高速涂布时容易出现重量分布不均匀的问题，由此导致电化学装置极化增大，容易出现局部析锂，影响电化学装置的循环性能和倍率性能。
发明内容
鉴于以上所述现有技术的缺点，本申请中提高了正极材料的加工性能和循环性能。
在本申请提出一种正极材料，正极材料中含有Al元素或Zr元素中的至少一种；正极材料颗粒满足0.01≤(Dv99 a－Dv99 b)/Dv99 b≤0.5；Dv99 a和Dv99 b分别为超声波处理前和超声波处理后测得的正极材料颗粒的Dv99的值。
在一些实施例中，正极材料颗粒满足：0.01≤(Dv50 a－Dv50 b)/Dv50 b≤0.30； Dv50 a和Dv50 b分别为超声波处理前和超声波处理后测得的正极材料颗粒的Dv50的值。
在一些实施例中，正极材料满足如下条件(a)至(d)中的至少一者：
(a)Dv50 a满足：2μm≤Dv50 a≤17μm；
(b)Dv99 a满足：6μm≤Dv99 a≤40μm；
(c)正极材料的比表面积BET满足：0.1m 2/g≤BET≤0.9m 2/g；
(d)正极材料中包含一次颗粒，所述一次颗粒粒径的平均值A满足：200nm≤A≤4μm。
在一些实施例中，正极材料满足如下条件(e)至(i)中的至少一者：
(e)Dv50 a满足：3μm≤Dv50 a≤6μm；
(f)Dv99 a满足：8μm≤Dv99 a≤30μm；
(g)正极材料的比表面积BET满足：0.5m 2/g≤BET≤0.8m 2/g；
(h)正极材料中包含一次颗粒，所述一次颗粒粒径的平均值A满足：1μm≤A≤4μm；
(i)Al元素占正极材料的质量比为0.05％至0.5％。
在一些实施例中，正极材料包含第一颗粒和第二颗粒，第一颗粒粒径为D1，第二颗粒粒径为D2，D2＜D1。
在一些实施例中，第一颗粒和第二颗粒满足如下条件(j)至(k)中的至少一者：
(j)0.01≤(Dv50 a1－Dv50 b1)/Dv50 b1≤0.1；
(k)0.01≤(Dv99 a1－Dv99 b1)/Dv99 b1≤0.25；
Dv50 a1和Dv50 b1分别为超声波处理前和超声波处理后测得的第一颗粒的Dv50的值，Dv99 a1和Dv99 b1分别为超声波处理前和超声波处理后测得的第一颗粒的Dv99的值。
在一些实施例中，第二颗粒满足如下条件(l)至(m)中的至少一条
(l)0.05≤(Dv50 a2－Dv50 b2)/Dv50 b2≤0.3；
(m)0.2≤(Dv99 a2－Dv99 b2)/Dv99 b2≤1；
Dv50 a2和Dv50 b2分别为超声波处理前和超声波处理后测得的第二颗粒的Dv50的值，Dv99 a2和Dv99 b2分别为超声波处理前和超声波处理后测得的第 二颗粒的Dv99的值。
在一些实施例中，第一颗粒和第二颗粒满足条件(n)至(p)中的至少一条:
(n)7μm≤Dv50 a1≤15μm；
(o)2μm≤Dv50 a2≤8μm；
(p)1.5≤Dv50 a1/Dv50 a2≤5.5；
Dv50 a1和Dv50 a2分别为超声波处理前测得的第一颗粒和第二颗粒的Dv50的值。
在一些实施例中，第一颗粒包含一次颗粒，第一颗粒中的一次颗粒的粒径的平均值A 1满足：300nm≤A 1≤800nm；和/或，第二颗粒包含一次颗粒，第二颗粒中的一次颗粒的粒径的平均值A 2满足：0.2μm≤A 2≤4μm。
本申请还提出一种电化学装置，包括：
正极；负极；隔离膜，设置在正极和负极之间；正极包括：正极集流体和设置在正极集流体上的正极活性物质层，正极活性物质层包括：上述任一项正极材料。
本申请还提供了一种电子装置，包括上述电化学装置。
本申请提出一种正极材料、电化学装置和电子装置，其中正极材料中含有Al元素或Zr元素中的至少一种；正极材料颗粒满足0.01≤(Dv99 a－Dv99 b)/Dv99 b≤0.5；Dv99 a和Dv99 b分别为超声波处理前和超声波处理后测得的正极材料颗粒的Dv99的值。本申请提出的正极材料能够改善正极材料的加工性能和电化学装置的循环性能。
具体实施方式
下面的实施例可以使本领域技术人员更全面地理解本申请，但不以任何方式限制本申请。
相关技术中通过减小材料的粒径以提高电化学装置的倍率性能，小颗粒的正极材料的加工性能较差，并且容易发生自团聚造成涂布时出现颗粒或气泡等问题，并且在高速涂布时容易出现重量分布不均匀的问题，造成电化学装置极化增大，出现析锂，影响电化学装置的循环性能和倍率性能，并导致电化学装置温升明显。
为了至少部分解决上述问题，在本申请的一些实施例中提出一种正极材料，正极材料中含有Al元素或Zr元素中的至少一种；正极材料颗粒满足0.01≤(Dv99 a－Dv99 b)/Dv99 b≤0.5。Dv99 a和Dv99 b分别为超声波处理前和超声波处理后测得的正极材料颗粒的Dv99的值。
在本申请的一些实施例中，正极材料包括正极材料颗粒，正极材料例如可以是含有Al元素或Zr元素中至少一种的钴酸锂材料，一些实施例中Al可以是位于正极材料表面的包覆层内，Zr可以是掺杂在正极材料中。0.01≤(Dv99 a－Dv99 b)/Dv99 b≤0.5这表明正极材料颗粒在超声处理前和超声处理后的Dv99的变化较小，因此可以知道正极材料自团聚情况较轻或几乎没有自团聚，从而保证该正极材料的加工性能，减少正极材料在涂布时不均匀的情况，从而改善电化学装置局部析锂问题，(Dv99 a－Dv99 b)/Dv99 b的数值过高时，采用该正极材料的电化学装置的循环性能差，温升高，本申请通过控制0.01≤(Dv99 a－Dv99 b)/Dv99 b≤0.5从而能够提高正极材料的加工性能，防止采用该正极材料的电化学装置析锂，并保证电化学装置的循环性能并减小温升。
在本申请一些实施例中，超声前后的粒径通过Mastersizer 3000激光粒度分布测试仪进行分析。激光粒度测试是根据不同大小的颗粒能使激光产生不同强度散射的原理来测试粒度分布的。Dv50表示在体积基准的粒度分布中，从小粒径侧起、达到体积累积50％的粒径。Dv99表示在体积基准的粒度分布中，从小粒径侧起、达到体积累积99％的粒径。用激光粒度仪测试超声前和超声后的正极材料颗粒时，除超声前处理外，其它测试条件完全一致，分散剂为水，分散方法采用外部超声，超声时间为5min，超声强度为40KHz180w，进样操作为全部进样。
对于已有的电化学装置，在测试电化学装置中采用的正极材料时，可以在2％相对湿度的干燥房内采用如下方法获取电化学装置中的正极材料，选取一个电化学装置，进行满放后，拆开电化学装置，获取到正极，将正极在NMP(N-甲基吡咯烷酮)溶液里浸泡24h后，在650℃下空气氛围煅烧5h，将正极上的活性物质层刮下，将得到的正极材料粉末研磨均匀，过400目的筛网，将通过400目筛网的粉末收集起来，即为正极材料。
在一些实施例中，正极材料颗粒满足：0.01≤(Dv50 a－Dv50 b)/Dv50 b≤0.30；Dv50 a和Dv50 b分别为超声波处理前和超声波处理后测得的正极材料颗粒的Dv50的值。在一些实施例中，在超声波处理前和超声波处理后测得的正极材料颗粒的Dv50的变化较小，因此可以知道正极材料颗粒自团聚情况较轻或几乎没有自团聚，从而有利于提高采用该正极材料的电化学装置的循环性能、减少电化学装置的温升并防止出现局部析锂。
在本申请一些实施例中，Dv50 a满足：2μm≤Dv50 a≤17μm，一些实施例中，Dv50 a满足：3μm≤Dv50 a≤6μm。
在本申请一些实施例中，Dv99 a满足：6μm≤Dv99 a≤40μm，一些实施例中，Dv99 a满足：8μm≤Dv99 a≤30μm。
一些实施例中，正极材料颗粒的粒径影响采用该正极材料的电化学装置的循环性能和温升，正极材料颗粒的粒径小，电化学装置的循环容量保持率越小且温升高，因此一些实施例中限定正极材料颗粒的Dv50 a和Dv99 a的最小值，另一方面，正极材料颗粒的粒径较大时会影响倍率性能，因此一些实施例中限定Dv50 a和Dv99 a的最大值。
在一些实施例中，正极材料的比表面积BET满足：0.1m 2/g≤BET≤0.9m 2/g，一些实施例中，正极材料的比表面积BET满足：0.5m 2/g≤BET≤0.8m 2/g。一些实施例中，正极材料的比表面积过小时，会造成倍率性能不佳，而当正极材料的比表面积过大时，造成采用该正极材料的电化学装置的电解液消耗增加。
在一些实施例中，正极材料中包含一次颗粒，一次颗粒粒径的平均值A满足：200nm≤A≤4μm，一些实施例中，正极材料中包含一次颗粒，一次颗粒粒径的平均值A满足：1μm≤A≤4μm。一些实施例中，增加一次颗粒粒径的平均值A有利于提高采用该正极材料的电化学装置的循环性能，因此限定A的最小值，但是，当一次颗粒粒径的平均值A过大时，采用该正极材料的电化学装置的温升会增加，动力学性能会劣化，因此限定A的最大值。一些实施例中，通过扫描电子显微镜测试正极材料的一些粒径，将本申请的正极材料通过500倍的扫描电子显微镜(德国ZEISS Sigma-02-33)成像后，在其电子显微图像中随机选取200至600个形状完整且无遮档的正极材料的一次颗粒，并记录一次颗粒在显微图像中最长直径的平均值作为平均粒径。
在本申请一些实施例中，Al元素占正极材料的质量比为0.05％至0.5％。
在本申请一些实施例中，正极材料包含第一颗粒和第二颗粒，第一颗粒粒径为D1，第二颗粒粒径为D2，D2＜D1。本申请一些实施例中采用泰勒筛制。一些实施例中，通过如下方式获取第一颗粒和第二颗粒，在2％相对湿度的干燥房取一部分正极材料，均匀分散在NMP溶液内，超声分散12h后，搅拌均匀，得到悬浊液，将该悬浊液一边搅，一边缓慢倒入1500目的筛网上，一部分小颗粒通过筛网进入到滤液中，将这些滤液静置24h后，倒掉上清液，烘干后得到的粉末即为本申请中的第二颗粒；一部分大颗粒在筛网上，烘干后得到的粉末即为本申请中的第一颗粒。
在一些实施例中，第一颗粒和第二颗粒满足：0.01≤(Dv50 a1－Dv50 b1)/Dv50 b1≤0.1。在一些实施例中，第一颗粒和第二颗粒满足：0.01≤Dv99 a1－Dv99 b1)/Dv99 b1≤0.25。其中，Dv50 a1和Dv50 b1分别为超声波处理前和超声波处理后测得的第一颗粒的Dv50的值，Dv99 a1和Dv99 b1分别为超声波处理前后测得的第一颗粒的Dv99的值。
在一些实施例中，第二颗粒满足：0.05≤(Dv50 a2－Dv50 b2)/Dv50 b2≤0.3。在一些实施例中，第二颗粒满足：0.2≤(Dv99 a2－Dv99 b2)/Dv99 b2≤1。Dv50 a2和Dv50 b2分别为超声波处理前和超声波处理后测得的第二颗粒的Dv50的值，Dv99 a2和Dv99 b2分别为超声波处理前和超声波处理后测得的第二颗粒的Dv99的值。
一些实施例中，当第一颗粒和第二颗粒满足上述条件时，表明第一颗粒和第二颗粒的很少团聚，从而有利于提高正极材料的加工性能，防止采用该正极材料的电化学装置出现析锂问题。
在一些实施例中，第一颗粒和第二颗粒满足：7μm≤Dv50 a1≤15μm。
在一些实施例中，第一颗粒和第二颗粒满足：2μm≤Dv50 a2≤8μm。
在一些实施例中，第一颗粒和第二颗粒满足：1.5≤Dv50 a1/Dv50 a2≤5.5。
Dv50 a1和Dv50 a2分别为超声波处理前测得的第一颗粒和第二颗粒的Dv50的值。
在一些实施例中，当第一颗粒和第二颗粒的Dv50满足上述条件时，正极活性层具有较好的压实密度，提高电化学装置的能量密度。
在一些实施例中，第一颗粒包含一次颗粒，第一颗粒中的一次颗粒的粒径的平均值A 1满足：300nm≤A 1≤800nm。
在一些实施例中，第一颗粒包含一次颗粒，第一颗粒中的一次颗粒的粒径的平均值A 1满足：500nm≤A 1≤800nm。
在一些实施例中，第二颗粒包含一次颗粒，第二颗粒中的一次颗粒的粒径的平均值A 2满足：0.2μm≤A 2≤4μm。
在一些实施例中，第一颗粒或第二颗粒中的至少一者的一次颗粒的粒径的平均值满足上述条件时，电化学装置具有平衡的循环性能和安全性能。
本申请还提出一种电化学装置，包括：正极、负极和隔离膜。
在本申请的一些实施例中，上述电化学装置的正极包括正极集流体和设置在正极集流体上的正极材料。正极材料可以是上述任一的正极材料。
在一些实施方案中，正极材料包括够吸收和释放锂(Li)的正极材料。能够吸收/释放锂(Li)的正极材料的例子可以包括钴酸锂、镍钴锰酸锂、镍钴铝酸锂、锰酸锂、磷酸锰铁锂、磷酸钒锂、磷酸钒氧锂、磷酸铁锂、钛酸锂和富锂锰基材料。
具体的，钴酸锂的化学式可以如化学式1：
Li xCo aM1 bO 2-c      化学式1
其中M1表示选自镍(Ni)、锰(Mn)、镁(Mg)、铝(Al)、硼(B)、钛(Ti)、钒(V)、铬(Cr)、铁(Fe)、铜(Cu)、锌(Zn)、钼(Mo)、锡(Sn)、钙(Ca)、锶(Sr)、钨(W)、钇(Y)、镧(La)、锆(Zr)和硅(Si)中的至少一种，x、a、b和c值分别在以下范围内：0.8≤x≤1.2、0.8≤a≤1、0≤b≤0.2、-0.1≤c≤0.2。
镍钴锰酸锂或镍钴铝酸锂的化学式可以如化学式2：
Li yNi dM2 eO 2-f      化学式2
其中M2表示选自钴(Co)、锰(Mn)、镁(Mg)、铝(Al)、硼(B)、钛(Ti)、钒(V)、铬(Cr)、铁(Fe)、铜(Cu)、锌(Zn)、钼(Mo)、锡(Sn)、钙(Ca)、锶(Sr)、钨(W)、锆(Zr)和硅(Si)中的至少一种，y、d、e和f值分别在以下范围内：0.8≤y≤1.2、0.3≤d≤0.98、0.02≤e≤0.7、-0.1≤f≤0.2。
锰酸锂的化学式可以如化学式3：
Li zMn 2-gM3 gO 4-h     化学式3
其中M3表示选自钴(Co)、镍(Ni)、镁(Mg)、铝(Al)、硼(B)、钛(Ti)、钒(V)、铬(Cr)、铁(Fe)、铜(Cu)、锌(Zn)、钼(Mo)、锡(Sn)、钙(Ca)、锶(Sr)和钨(W)中的至少一种，z、g和h值分别在以下范围内：0.8≤z≤1.2、0≤g<1.0和-0.2≤h≤0.2。
在一些实施例中，上述电化学装置的正极中可以加有导电剂或正极粘结剂，在本申请的一些实施例中，正极还包括碳材料，碳材料可以包括导电炭黑、石墨、石墨烯、碳纳米管、碳纤维或炭黑中的至少一种。正极粘结剂可以包括聚偏氟乙烯、偏氟乙烯-六氟丙烯的共聚物、苯乙烯-丙烯酸酯共聚物、苯乙烯-丁二烯共聚物、聚酰胺、聚丙烯腈、聚丙烯酸酯、聚丙烯酸、聚丙烯酸盐、羧甲基纤维素纳、聚醋酸乙烯酯、聚乙烯呲咯烷酮、聚乙烯醚、聚甲基丙烯酸甲酯、聚四氟乙烯或聚六氟丙烯中的至少一种。
在一些实施例中，负极包括负极集流体和负极材料。负极材料位于负极集流体上。在一些实施例中，负极集流体可以包括铜箔、铝箔、镍箔或碳氟集流体中的至少一种。在一些实施例中，负极材料中还包括负极导电剂和/或负极粘结剂。在一些实施例中，负极粘结剂可以包括羧甲基纤维素(CMC)、聚丙烯酸、聚乙烯基吡咯烷酮、聚苯胺、聚酰亚胺、聚酰胺酰亚胺、聚硅氧烷、聚丁苯橡胶、环氧树脂、聚酯树脂、聚氨酯树脂或聚芴中的至少一种。在一些实施例中，负极粘结剂在负极材料中的质量百分比为0.5％至10％。在一些实施例中，负极导电剂可以包括导电炭黑、科琴黑、乙炔黑、碳纳米管、VGCF(Vapor Grown Carbon Fiber，气相成长碳纤维)或石墨烯中的至少一种。
在一些实施例中，隔离膜包括聚乙烯、聚丙烯、聚偏氟乙烯、聚对苯二甲酸乙二醇酯、聚酰亚胺或芳纶中的至少一种。例如，聚乙烯包括选自高密度聚乙烯、低密度聚乙烯或超高分子量聚乙烯中的至少一种。尤其是聚乙烯和聚丙烯，它们对防止短路具有良好的作用，并可以通过关断效应改善电池的稳定性。
本申请还提出一种电子装置，包括上述中任一项的电化学装置。本申请的电子装置没有特别限定，其可以是用于现有技术中已知的任何电子装置。在一些实施例中，电子装置可以包括，但不限于，笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便 携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机和家庭用大型蓄电池等。例如，电子装置包括含有锂离子电池的手机。
为了更好的说明本申请实施例中提出的电解液的有益效果，以下将结合实施例以及对比例进行说明。
实施例1：
正极材料制备：采用间歇共沉淀法制备Ni 0.8Co 0.1Mn 0.1(OH) 2前驱体，获得Span为0.60(Span＝(Dv90 a3－Dv10 a3)/Dv50 a3，其中Dv90 a3、Dv10 a3和Dv50 a3分别为超声波处理前测得的前驱体的粒径)，BET为10.2m 2/g,Dv50 a3为10.5μm的前驱体，将该前驱体、LiOH按Li/(Ni+Co+Mn)＝1.03摩尔比进行混合，在一次烧结温度820℃下一次烧结16h，通过水洗干燥后，得到初级物质。将初级物质进行破碎，粉碎气压为0.4MPa，经过水洗后，再将其和Al(OH) 3按Al/(Ni+Co+Mn)＝0.001的质量比混合均匀，在600℃烧结6h进行烧结，通过单层325目振筛进行筛分后，得到正极材料，此时得到的正极材料参数如表2实施例1数据所示。
正极制备：将正极材料、导电剂Super P、粘结剂聚偏二氟乙烯按照重量比97.9:0.4:1.7进行混合，加入N-甲基吡咯烷酮(NMP)，在真空搅拌机作用下搅拌均匀，获得正极浆料；将正极浆料均匀涂覆于正极集流体铝箔两个表面上；经过烘干、冷压、裁片、分切后，在真空条件下干燥，得到正极。
负极制备：将负极活性材料人造石墨、增稠剂羧甲基纤维素钠、粘结剂丁苯橡胶按照重量比97:1:2进行混合，加入去离子水，在真空搅拌机作用下获得负极浆料；将负极浆料均匀涂覆在负极集流体铜箔两个表面上，经过烘干、冷压、裁片、分切后，在真空条件下干燥，得到负极。
电解液制备：在干燥的氩气气氛手套箱中，将碳酸乙烯酯、碳酸丙烯酯及碳酸二甲酯按照2:2:6的比例混合均匀，添加锂盐LiPF 6，使得最终得到的电解液中锂盐浓度为1.10mol/L；基于电解液总重量加入1％的碳酸亚乙烯酯，混合均匀，得到电解液。
电池制备：以聚乙烯多孔聚合薄膜作为隔离膜，将正极、隔离膜、负极按顺序依次叠好，使隔离膜处于正极和负极中间起到隔离的作用，并卷绕得到电极组件。将电极组件置于外包装铝塑膜中，注入电解液并封装，经过化成，脱气，切边等工艺流程得到锂离子电池。
实施例2至实施例12：
实施例2至实施例12与实施例1的区别之处在于：正极材料制备时的前驱体的Span、前驱体的BET、前驱体Dv50 a3以及一次烧结温度中的至少一个不同，具体参数见表1。
实施例13：
实施例13与实施例1的区别在于正极材料制备方法不同，实施例13采用的正极材料制备方法如下：
采用间歇共沉淀法制备Ni 0.8Co 0.1Mn 0.1(OH) 2前驱体，获得Span为0.65，BET为16m 2/g,Dv50 a3为4.5μm的前驱体，将该前驱体、LiOH、ZrO 2按Li/(Ni+Co+Mn)＝1.03摩尔比、Zr/(Ni+Co+Mn)＝0.003的质量比进行混合，在一次烧结温度850℃下一次烧结16h，通过水洗干燥后，得到初级物质。将初级物质进行破碎，粉碎气压为0.6MPa，经过水洗后，再将其和Al(OH) 3按Al/(Ni+Co+Mn)＝0.001的质量比混合均匀，在600℃烧结6h进行烧结，通过上层254目和下层325目的双层振筛进行筛分后，得到正极材料。
实施例14至实施例16：
实施例14至实施例16与实施例13的区别之处在于：制备正极材料时的一次烧结温度、掺杂含量中的至少一个不同，具体参数见表3。
实施例17至实施例35：
实施例17至实施例35与实施例1的区别在于，实施例17至实施例35中采用的正极材料是将实施例1至实施例16中的任意两种正极材料进行混合得到，具体参数见表5。
对比例1：
对比例1与实施例1的区别在于正极材料制备方法不同，对比例1采用的正极材料制备方法如下：
采用连续共沉淀法制备Ni 0.8Co 0.1Mn 0.1(OH) 2前驱体，获得Span为1.1，BET为18m 2/g,Dv50 a3为4.5μm的前驱体，将该前驱体、LiOH按Li/(Ni+Co+Mn)＝1.03摩尔比进行混合，在一次烧结温度820℃下一次烧结16h，通过水洗干燥后，得到初级物质。将初级物质通过破碎、粉碎气压为0.6MPa，经过水洗后，再将其和H 3BO 3按B/(Ni+Co+Mn)＝0.002的质量比混合均匀，在400℃烧结6h进行烧结，通过单层325目振筛进行筛分后，得到正极材料。
对比例2：
对比例2与实施例1的区别在于正极材料制备方法不同，对比例2采用的正极材料制备方法如下：
采用连续共沉淀法制备Ni 0.8Co 0.1Mn 0.1(OH) 2前驱体，获得Span为1.1，BET为22m 2/g,Dv50 a3为4.5μm的前驱体，将该前驱体、LiOH按Li/(Ni+Co+Mn)＝1.03摩尔比进行混合，在一次烧结温度870℃下一次烧结16h，通过水洗干燥后，得到初级物质。将初级物质通过破碎、粉碎气压为0.7MPa，经过水洗后，再将其和H 3BO 3按B/(Ni+Co+Mn)＝0.002的质量比混合均匀，在400℃烧结6h进行烧结，通过单层325目振筛进行筛分后，得到正极材料。
对实施例和对比例中所制备的锂离子电池按照如下方法进行测试：
超声前后正极材料粒径的测定：超声前后的粒径通过Mastersizer 3000激光粒度分布测试仪进行分析。激光粒度测试是根据不同大小的颗粒能使激光产生不同强度散射的原理来测试粒度分布的。Dv50表示在体积基准的粒度分布中，从小粒径侧起、达到体积累积50％的粒径。Dv99表示在体积基准的粒度分布中，从小粒径侧起、达到体积累积99％的粒径。用激光粒度仪测试超声前后的粒径时，除超声前处理外，其它测试条件要完全一致。且分散剂为水，分散方法采用外部超声，超声时间为5min，超声强度为40KHz 180w，进样操作为全部进样。
一次颗粒粒径的测量：将实施例及对比例的正极材料通过500倍的扫描电子显微镜(德国ZEISS Sigma-02-33)成像后，在其电子显微图像中随机选 取200至600个形状完整且无遮档的正极材料的一次颗粒，并记录一次颗粒在显微图像中最长直径的平均值作为平均粒径。
循环性能测试：将以下实施例及对比例的锂离子电池置于45℃±2℃的恒温箱中静置2小时，以1.5C恒流充电至4.25V，然后以4.25V恒压充电至0.02C并静置15分钟；再以4.0C恒流放电至2.8V，此为一次充放电循环过程，记录锂离子电池首次循环的放电容量；而后按上述方法重复进行500次的充放电循环过程，并记录第500次循环的放电容量。
每组取4块锂离子电池，计算锂离子电池的容量保持率的平均值。锂离子电池的循环容量保持率＝第500次循环的放电容量(mAh)/首次循环后的放电容量(mAh)×100％。
循环后析锂程度判定：将循环后的电池以1.5C恒流充电至4.25V，拆解电芯，当负极整体显示为金黄色且显示为灰色的面积<2％，则判定为不析锂；当负极大部分为金黄色，但有部分位置可观察到灰色，灰色面积在2％至20％之间，则判定为轻微析锂；当负极部分为灰色，但仍可观察到部分金黄色，灰色面积在20％至60％，则判定为中度析锂；当负极大部分显示为灰色，灰色面积＞60％时，则判定为严重析锂。
温升测试：将实施例及对比例的锂离子电池置于25℃±2℃的恒温箱中静置2小时，以1.5C恒流充电至4.25V，然后以4.25V恒压充电至0.02C并静置15分钟；再以10C恒流放电至2.8V，此为一次充放电循环过程，如此再循环一圈，测试此时锂离子电池表面温度，减去初始的锂离子电池的温度即为温升。
过滤性：浆料的过滤性是指将400mL的正极浆料通过300目筛网所需要用的时间，用秒作单位，时间越短，说明浆料的过滤性越好。
第一颗粒和第二颗粒的分离：在2％相对湿度的干燥房内取一部分用正极材料，均匀分散在NMP溶液内，超声分散12h后，搅拌均匀，得到含正极材料的悬浊液，将该悬浊液一边搅，一边缓慢倒入1500目的筛网上，一部分小颗粒通过筛网进入到滤液中，将这些滤液静置24h后，倒掉上清液，烘干后得到的粉末即为第二颗粒，另一部分大颗粒在筛网上，烘干后得到的粉末即为第一颗粒。
实施例1至实施例12、对比例1至对比例2的正极材料制备的参数如表1所示，实施例1至实施例12、对比例1至对比例2的测试结果如表2所示。
表1
Figure PCTCN2021104957-appb-000001
表2
Figure PCTCN2021104957-appb-000002
如表1和表2所示，在实施例1至实施例4中通过控制前驱体的Span、BET、一次烧结温度和粉碎气压从而调整正极材料的(Dv99 a－Dv99 b)/Dv99 b，一次烧结温度降低会在一定程度上造成Dv50a减小；前驱体的Span越高、前驱体BET越小、一次烧结温度越低、粉碎气压越低，则正极材料(Dv99 a－ Dv99 b)/Dv99 b、Dv99 a和正极材料BET越大，但是过小的Span、前驱体BET、粉碎气压和过大的一次烧结温度会造成成本增加，并且导致容量降低。因此这些参数都需要控制在一定的范围内。
从表2可以看出，实施例1至实施例12为未出现析锂或轻微析锂，而对比例1和对比例2中均出现了析锂，并且对比例1和对比例2的过滤性较差，这是因为对比例1和对比例2中(Dv99 a－Dv99 b)/Dv99 b和(Dv50 a－Dv50 b)/Dv50 b过大，浆料的过滤性主要受(Dv99 a－Dv99 b)/Dv99 b和(Dv50 a－Dv50 b)/Dv50 b的影响，这两个值越大，说明正极材料颗粒团聚越严重，浆料过滤性越差，在正极材料团聚程度严重的情况下，在制备正极时容易涂覆不均，造成锂离子电池局部析锂。因此，在本申请的一些实施例中限定0.01≤(Dv99 a－Dv99 b)/Dv99 b≤0.5，0.01≤(Dv50 a－Dv50 b)/Dv50 b≤0.15。
从表2中可以看出，对比例2的温升最高，这是因为温升同时受粒径大小、(Dv99 a－Dv99 b)/Dv99 b和(Dv50 a－Dv50 b)/Dv50 b的影响，粒径的影响最大，粒径越大，温升越高。同时，相同的粒径下，(Dv99 a－Dv99 b)/Dv99 b和(Dv50 a－Dv50 b)/Dv50 b的值越大，温升会更高。
对比例1的循环容量保持率最低，这是因为循环容量保持率主要受粒径大小的影响，粒径越大，循环容量保持率相对越高，相同粒径下，(Dv99 a－Dv99 b)/Dv99 b和(Dv50 a－Dv50 b)/Dv50 b的值越大，循环容量保持率会越低。
表3
Figure PCTCN2021104957-appb-000003
表4
Figure PCTCN2021104957-appb-000004
Figure PCTCN2021104957-appb-000005
实施例13至实施例16的正极材料制备方法的参数如表3所示，其性能测试结果如表4所示，在实施例13至实施例16中通过调整一次烧结温度、掺杂元素和含量、筛分方式来调整正极材料的(Dv99 a－Dv99 b)/Dv99 b和(Dv50 a－Dv50 b)/Dv50 b的大小，同时还对一次颗粒的大小进行了调节。
对比实施例13至实施例16与实施例1至实施例12可以看出，实施例13至实施例16的循环容量保持率明显升高，这是主要是因为在实施例13至实施例16中一次颗粒的粒径增大到1μm以上，一次颗粒的粒径(正极材料的一次粒径)大循环性能较好，从表3中实施例13至实施例15可以看出，通过升高一次烧结温度，能够增大一次颗粒粒径，从表3中实施例15至实施例16可以看出，通过增加一些可以助熔的掺杂元素如Zr元素也可以增大一次颗粒粒径，并且通过升高一次烧结温度或增加Zr元素有利于较小(Dv99a－Dv99b)/Dv99b和(Dv50a－Dv50b)/Dv50b的数值，即团聚程度也有所减轻。因此，在一些实施例中限定正极材料的一次粒径的平均值A不小于1μm。
对比表4中实施例13至实施例16可看出，随着一次颗粒粒径的增大，锂离子电池的温升也会升高，导致锂离子电池的动力学性能会变差，即当一次粒径过大时会造成锂离子电池性能的恶化，因此在一些实施例中限定正极材料的一次粒径的平均值A不大于4μm。
表5
Figure PCTCN2021104957-appb-000006
Figure PCTCN2021104957-appb-000007
表6
Figure PCTCN2021104957-appb-000008
Figure PCTCN2021104957-appb-000009
表7
Figure PCTCN2021104957-appb-000010
在实施例17至实施例35中将实施例1至实施例16中的任意两种正极材料进行混合，混合比例如表5所示。表6中显示了实施例17至实施例35的物理参数，表7显示了性能测试结果。
在表5中的第一正极材料的粒径大于第二正极材料的粒径，实施例17至实施例27采用大颗粒多晶和小颗粒多晶的组合，实施例28至实施例35采用大颗粒多晶和小颗粒单晶的组合，实施例32至实施例35中采用不同的质量比，从表7可以看出，采用各种混合方式的实施例15至实施例35在循环后均未出现析锂状况，并且循环容量保持率均较好，由此可见，只要正极材料能够满足1％≤(Dv99 a－Dv99 b)/Dv99 b≤50％，1％≤(Dv50 a－ Dv50 b)/Dv50 b≤15％的条件，锂离子电池就不会出现析锂，且能够保持较好的循环容量保持率。
以上描述仅为本申请的较佳实施例以及对所运用技术原理的说明。本领域技术人员应当理解，本申请中所涉及的公开范围，并不限于上述技术特征的特定组合而成的技术方案，同时也应涵盖在不脱离上述公开构思的情况下，由上述技术特征或其等同特征进行任意组合而形成的其它技术方案。例如上述特征与本申请中公开的具有类似功能的技术特征进行互相替换而形成的技术方案。

Claims (11)

  1. 一种正极材料，其特征在于，
    所述正极材料中含有Al元素或Zr元素中的至少一种；
    正极材料颗粒满足0.01≤(Dv99 a－Dv99 b)/Dv99 b≤0.5；
    Dv99 a和Dv99 b分别为超声波处理前和超声波处理后测得的正极材料颗粒的Dv99的值。
  2. 根据权利要求1的正极材料，所述正极材料颗粒满足：
    0.01≤(Dv50 a－Dv50 b)/Dv50 b≤0.30；
    Dv50 a和Dv50 b分别为超声波处理前和超声波处理后测得的正极材料颗粒的Dv50的值。
  3. 根据权利要求1所述的正极材料，其特征在于，所述正极材料满足如下条件(a)至(d)中的至少一者：
    (a)Dv50 a满足：2μm≤Dv50 a≤17μm；
    (b)所述Dv99 a满足：6μm≤Dv99 a≤40μm；
    (c)所述正极材料的比表面积BET满足：0.1m 2/g≤BET≤0.9m 2/g；
    (d)所述正极材料中包含一次颗粒，所述一次颗粒粒径的平均值A满足：200nm≤A≤4μm；
    其中，所述Dv50 a为超声波处理前测得的正极材料颗粒的Dv50的值。
  4. 根据权利要求1所述的正极材料，其特征在于，所述正极材料满足条件(e)至(i)中的至少一者：
    (e)Dv50 a满足：3μm≤Dv50 a≤6μm；
    (f)Dv99 a满足：8μm≤Dv99 a≤30μm；
    (g)所述正极材料的比表面积BET满足：0.5m 2/g≤BET≤0.8m 2/g；
    (h)所述正极材料中的一次粒径的平均值A满足：1μm≤A≤4μm；
    (i)所述Al元素占所述正极材料的质量比为0.05％至0.5％；
    其中，所述Dv50 a为超声波处理前测得的正极材料颗粒的Dv50的值。
  5. 根据权利要求1所述的正极材料，其特征在于，
    所述正极材料包含第一颗粒和第二颗粒，所述第一颗粒粒径为D1，第二颗粒粒径为D2，D2＜D1。
  6. 根据权利要求5所述的正极材料，其特征在于，所述第一颗粒满足如下条件(j)至(k)中的至少一者：
    (j)0.01≤(Dv50 a1－Dv50 b1)/Dv50 b1≤0.1；
    (k)0.01≤(Dv99 a1－Dv99 b1)/Dv99 b1≤0.25
    Dv50 a1和Dv50 b1分别为超声波处理前和超声波处理后测得的第一颗粒的Dv50的值，Dv99 a1和Dv99 b1分别为超声波处理前和超声波处理后测得的第一颗粒的Dv99的值。
  7. 根据权利要求5所述的正极材料，其特征在于，
    所述第二颗粒满足如下条件(l)至(m)中的至少一条
    (l)0.05≤(Dv50 a2－Dv50 b2)/Dv50 b2≤0.3；
    (m)0.2≤(Dv99 a2－Dv99 b2)/Dv99 b2≤1；
    Dv50 a2和Dv50 b2分别为超声波处理前和超声波处理后测得的第二颗粒的Dv50的值，Dv99 a2和Dv99 b2分别为超声波处理前和超声波处理后测得的第二颗粒的Dv99的值。
  8. 根据权利要求5所述的正极材料，其特征在于，
    所述第一颗粒和所述第二颗粒满足条件(n)至(p)中的至少一条:
    (n)7μm≤Dv50 a1≤15μm
    (o)2μm≤Dv50 a2≤8μm
    (p)1.5≤Dv50 a1/Dv50 a2≤5.5
    Dv50 a1和Dv50 a2分别为超声波处理前测得的第一颗粒和第二颗粒的Dv50的值。
  9. 根据权利要求5所述的正极材料，其特征在于，
    所述第一颗粒包含一次颗粒，所述第一颗粒中的一次颗粒的粒径的平均值A 1满足：300nm≤A 1≤800nm；和/或，
    所述第二颗粒包含一次颗粒，所述第二颗粒中的一次颗粒的粒径的平均值A 2满足：0.2μm≤A 2≤4μm。
  10. 一种电化学装置，包括：
    正极；
    负极；
    隔离膜，设置在所述正极和所述负极之间；
    所述正极包括：正极集流体和设置在所述正极集流体上的正极活性物质层，所述正极活性物质层包括：权利要求1至9任一项所述正极材料。
  11. 一种电子装置，包括如权利要求10所述的电化学装置。
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