WO2022198852A1 - 正极活性材料及使用其的电化学装置和电子装置 - Google Patents

正极活性材料及使用其的电化学装置和电子装置 Download PDF

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WO2022198852A1
WO2022198852A1 PCT/CN2021/107115 CN2021107115W WO2022198852A1 WO 2022198852 A1 WO2022198852 A1 WO 2022198852A1 CN 2021107115 W CN2021107115 W CN 2021107115W WO 2022198852 A1 WO2022198852 A1 WO 2022198852A1
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positive electrode
active material
electrode active
particles
lanthanum
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PCT/CN2021/107115
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English (en)
French (fr)
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王亮
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宁德新能源科技有限公司
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Priority to EP21932466.2A priority Critical patent/EP4318659A1/en
Priority to JP2023557768A priority patent/JP2024510336A/ja
Publication of WO2022198852A1 publication Critical patent/WO2022198852A1/zh
Priority to US18/371,567 priority patent/US20240021815A1/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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—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
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/381—Alkaline or alkaline earth metals elements
    • H01M4/382—Lithium
    • 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
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/46—Alloys based on magnesium or aluminium
    • H01M4/463—Aluminium based
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the field of energy storage, and in particular, to a positive electrode active material and an electrochemical device and an electronic device using the same.
  • Electrochemical devices eg, lithium-ion batteries
  • consumer electronics such as notebook computers, mobile phones, handheld game consoles, tablets
  • the requirements for electrochemical devices are also increasing, including their portability, capacity, cycle performance, storage performance, working life, and fast charging performance.
  • How to improve the fast charging performance of electrochemical devices has become one of the key directions of research and development.
  • the development of new cathode active materials is one of the ways to improve the fast charging performance of electrochemical devices.
  • traditional cathode active materials still face many problems under high-voltage operating conditions, and their applications are greatly limited.
  • the present application attempts to solve at least one problem in the related art, at least to some extent, by providing a cathode active material suitable for use under high voltage operating conditions.
  • the present application provides a positive electrode active material, at least a part of a surface area of the positive electrode active material contains aluminum element, and the aluminum in the surface area is based on the weight of the positive electrode active material.
  • the content of the element is A wt%, and A is 0.01 to 1.
  • the inner region of the positive electrode active material contains aluminum element, the content of the aluminum element in the inner region is A 1 wt % based on the weight of the positive electrode active material, and A 1 satisfies the following At least one of the conditions: (a) A 1 is 0.05 to 2; (b) A 1 >A; (c) 1 ⁇ A 1 /A ⁇ 10.
  • At least a part of the surface area of the positive electrode active material further includes lanthanum, and the content of the lanthanum element in at least a part of the surface area is B wt based on the weight of the positive electrode active material %, B satisfies at least one of the following conditions: (d) B is 0.01 to 0.8; (e) 0.01 ⁇ B/A ⁇ 0.8.
  • At least a portion of the surface region of the positive electrode active material further contains at least one element of lithium, cobalt, nickel, manganese, magnesium, titanium, zirconium, fluorine, or yttrium.
  • the inner region of the positive electrode active material contains lanthanum, and the content of the lanthanum element in the inner region is D wt % based on the weight of the positive electrode active material, and D satisfies the following conditions At least one of: (f) D is 0.01 to 0.4; (g) B>D; (h) 1 ⁇ B/D ⁇ 10.
  • the positive electrode active material includes first particles and second particles, and the average particle diameter of the first particles is larger than the average particle diameter of the second particles.
  • the positive electrode active material satisfies at least one of the following conditions: (i) the Dv50 of the first particles is 10 ⁇ m to 15 ⁇ m; (j) the Dv99 of the first particles is 20 ⁇ m to 30 ⁇ m (k) the Dv50 and Dv99 of the first particles satisfy: 1.5 ⁇ Dv99/Dv50 ⁇ 3; (l) the Dv50' of the second particles is 2 ⁇ m to 6 ⁇ m; or (m) the Dv50 of the first particles The Dv50' of the second particles satisfies: 2 ⁇ Dv50/Dv50' ⁇ 8.
  • the second particles include secondary particles, and the primary particles forming the secondary particles have an average particle diameter of 0.1 ⁇ m to 3 ⁇ m.
  • the second particles are polycrystalline particles.
  • the content of lanthanum in the first particles is smaller than the content of lanthanum in the second particles.
  • the content of lanthanum in the first particles is E wt %
  • the content of lanthanum in the second particles is F wt %
  • E 0.01 to 0.6
  • F 0.01 to 0.9.
  • the peak intensity ratio of the strongest peak in the range of 23.0°-24.0° and the strongest peak in the range of 32.5°-33.5° of the positive electrode active material is 0.6 to 1.5.
  • the positive electrode active material includes at least one of cobalt lithium oxide, manganese lithium oxide, or nickel cobalt manganese lithium oxide.
  • the present application provides a method for preparing the positive electrode active material described in the present application, comprising:
  • Step S1 sintering the mixture including the positive electrode active material precursor material at a temperature of 600° C. to 1500° C. to obtain a primary positive electrode active material X;
  • Step S2 sintering the raw material including the primary positive electrode active material X and the compound containing aluminum element at a temperature of 600°C to 1000°C to obtain a positive electrode active material.
  • the application also provides a method for preparing the positive electrode active material described in the application, comprising:
  • Step S1-1 sintering the first mixture including the first cathode active material precursor material at a temperature T1 to obtain a first primary cathode active material X1;
  • Step S2-1 sintering the first raw material including the first primary cathode active material X1 and the first compound containing aluminum element at temperature T1' to obtain first particles;
  • Step S1-2 sintering the second mixture including the second cathode active material precursor material at a temperature T2 to obtain a second primary cathode active material X2;
  • Step S2-2 sintering the second raw material including the second primary cathode active material X2 and the second compound containing aluminum element at temperature T2' to obtain second particles;
  • Step S3 mixing the first particles and the second particles to obtain the positive electrode active material.
  • the sintering time is 4 hours to 12 hours.
  • the temperature T1 is 800°C to 1150°C.
  • the sintering time is 8 to 24 hours.
  • the temperature T1' is 700°C to 1000°C.
  • step S2-1 the sintering time is 4 to 12 hours.
  • the temperature T2 is 800°C to 1050°C.
  • the sintering time is 8 to 24 hours.
  • the temperature T2' is 600°C to 950°C.
  • the sintering time is 4 to 12 hours.
  • At least one of the mixture, the first mixture, or the second mixture optionally includes a compound having aluminum element, magnesium element, titanium element, zirconium element, or yttrium element.
  • At least one of the mixture, the first mixture or the second mixture further includes a compound containing aluminum element.
  • At least one of the mixture, the first mixture, or the second mixture includes aluminum element, and optionally a compound having magnesium element, titanium element, zirconium element, or yttrium element.
  • At least one of the raw material, the first raw material, or the second raw material optionally includes at least one element of nickel, manganese, magnesium, titanium, zirconium, fluorine, or yttrium .
  • At least one of the raw material, the first raw material or the second raw material optionally includes elements having nickel, manganese, magnesium, titanium, zirconium, fluorine or Compounds of the element yttrium.
  • At least one of the mixture, the first mixture, or the second mixture further includes a lanthanum-containing compound.
  • the content of the lanthanum element is 0.01% to 5% based on the weight of the mixture, the first mixture or the second mixture.
  • At least one of the mixture, the first mixture, or the second mixture further includes a compound containing an M element, the M element including at least one of the following elements: lithium, cobalt , nickel, manganese, magnesium, titanium, zirconium, fluorine, yttrium, niobium, boron, molybdenum, vanadium and cerium.
  • At least one of the mixture, the first mixture, or the second mixture further includes a compound containing an M element, the M element including lithium, cobalt, and at least one of the following elements : Lithium, cobalt, nickel, manganese, magnesium, titanium, zirconium, fluorine, yttrium, niobium, boron, molybdenum, vanadium and cerium.
  • At least one of the mixture, the first mixture or the second mixture further includes a compound containing an M element, the M element including at least one of the following elements: magnesium, titanium , zirconium, fluorine, yttrium, niobium, boron, molybdenum, vanadium and cerium.
  • At least one of the raw material, the first raw material or the second raw material further includes a compound containing M element, the M element including at least one of the following elements: lithium, cobalt , nickel, manganese, magnesium, titanium, zirconium, fluorine, yttrium, niobium, boron, molybdenum, vanadium and cerium.
  • At least one of the raw material, the first raw material, or the second raw material further includes a compound containing an M element, the M element including lithium, cobalt, and at least one of the following elements : Lithium, cobalt, nickel, manganese, magnesium, titanium, zirconium, fluorine, yttrium, niobium, boron, molybdenum, vanadium and cerium.
  • the compound containing M element is at least one of oxide of M element, hydroxide of M element, carbonate of M element, phosphate of M element, or fluoride of M element kind.
  • At least one of the positive electrode active material precursor material, the first positive electrode active material precursor material, and the second positive electrode active material precursor material includes a compound containing a cobalt element and lithium Salt.
  • the compound containing cobalt element includes at least one of cobalt oxide or cobalt hydroxide.
  • the lithium salt includes at least one of lithium carbonate, lithium oxide or lithium hydroxide.
  • the molar ratio of the compound containing cobalt element to the lithium salt is 0.90:1 to 1.1:1.
  • the first particles and the second particles are mixed in a mass ratio of 1:9 to 9:1 to obtain the positive electrode active material.
  • the present application provides an electrochemical device including a positive electrode, a negative electrode, and an electrolyte, wherein the positive electrode includes a positive electrode active material according to an embodiment of the present application.
  • the present application provides an electronic device including an electrochemical device according to an embodiment of the present application.
  • FIG. 1 shows a scanning electron microscope (SEM) image of the positive electrode active material used in Comparative Example 1.
  • SEM scanning electron microscope
  • FIG. 2 shows a scanning electron microscope (SEM) image of the positive electrode active material used in Example 7.
  • SEM scanning electron microscope
  • Example 3 shows the X-ray diffraction spectrum (XRD) of the positive electrode active materials used in Comparative Example 1 and Example 28.
  • a term may refer to a range of variation less than or equal to ⁇ 10% of the numerical value, such as less than or equal to ⁇ 5%, less than or equal to ⁇ 4%, less than or equal to ⁇ 3%, Less than or equal to ⁇ 2%, less than or equal to ⁇ 1%, less than or equal to ⁇ 0.5%, less than or equal to ⁇ 0.1%, or less than or equal to ⁇ 0.05%.
  • a list of items linked by the term "at least one of” can mean any combination of the listed items. For example, if items A and B are listed, the phrase "at least one of A and B" means A only; B only; or A and B. In another example, if items A, B, and C are listed, the phrase "at least one of A, B, and C" means A only; or B only; C only; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C.
  • Item A can contain a single element or multiple elements.
  • Item B may contain a single element or multiple elements.
  • Item C may contain a single element or multiple elements.
  • the positive electrode includes a positive electrode current collector and a positive electrode material disposed on the positive electrode current collector, and the positive electrode material includes a positive electrode active material.
  • the present application adopts a doping method to provide a specific content of aluminum element on the surface of the positive electrode active material, so as to improve the impedance, cycle performance and high temperature storage performance of the electrochemical device under high voltage working conditions.
  • the present application provides a positive electrode active material, at least a part of the surface area of the positive electrode active material contains aluminum element, and based on the weight of the positive electrode active material, the content of the aluminum element in the surface area is is A wt%, A is 0.01 to 1.
  • A is 0.2 to 0.8.
  • A is 0.3 to 0.6.
  • A is 0.01, 0.02, 0.04, 0.06, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, or within a range of any of the above.
  • the "surface area" of the positive electrode active material refers to the area of the outermost surface of the positive electrode active material particle in the range of less than or equal to 200 nm toward the center direction.
  • the impedance of the electrochemical device under high-voltage operating conditions can be significantly reduced and its cycle performance and high-temperature storage performance can be significantly improved.
  • the inner region of the positive electrode active material contains aluminum element, and the content of the aluminum element in the inner region is A 1 wt % based on the weight of the positive electrode active material, and A 1 satisfies the following conditions At least one of: (a) A 1 is 0.05 to 2; (b) A 1 >A; (c) 1 ⁇ A 1 /A ⁇ 10.
  • the "internal region" of the positive electrode active material refers to the region other than the surface region of the positive electrode active material particle.
  • a 1 is 0.05 to 1.5. In some embodiments, A 1 is 0.07 to 1.2. In some embodiments, A 1 is 0.1 to 1.0. In some embodiments, A 1 is 0.2 to 0.9. In some embodiments, A 1 is 0.05, 0.06, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.5, 1.8, 2, or any value above composition range.
  • a 1 A.
  • a 1 /A is 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 or any value above composition range.
  • At least a portion of the surface area of the positive electrode active material further comprises lanthanum, and the content of the lanthanum in at least a portion of the surface area is B wt % based on the weight of the positive electrode active material , B satisfies at least one of the following conditions: (d) B is 0.01 to 0.8; (e) 0.01 ⁇ B/A ⁇ 0.8.
  • B is 0.01 to 0.6. In some embodiments, B is 0.02 to 0.5. In some embodiments, B is 0.05 to 0.3. In some embodiments, B is 0.05 to 0.2. In some embodiments, B is 0.01, 0.03, 0.05, 0.07, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or within a range of any of the above.
  • the surface region of the positive electrode active material includes the lanthanum element satisfying the above-mentioned conditions, the impedance, cycle performance, and high-temperature storage performance of the electrochemical device under high-voltage operating conditions can be further improved.
  • At least a portion of the surface area of the positive active material further comprises at least one element of lithium, cobalt, nickel, manganese, magnesium, titanium, zirconium, fluorine, or yttrium. In some embodiments, at least a portion of the surface area of the positive active material further comprises lithium, cobalt, and at least one element of nickel, manganese, magnesium, titanium, zirconium, fluorine, or yttrium. In some embodiments, at least a portion of the surface area of the positive active material further includes at least one element of magnesium, titanium, zirconium, fluorine, or yttrium. When the surface region of the positive electrode active material contains the above-mentioned elements, the impedance, cycle performance, and high-temperature storage performance of the electrochemical device under high-voltage operating conditions can be further improved.
  • the inner region of the positive electrode active material contains lanthanum, the content of the lanthanum in the inner region is D wt % based on the weight of the positive electrode active material, and D satisfies at least one of the following conditions Where: (f) D is 0.01 to 0.4; (g) B>D; (h) 1 ⁇ B/D ⁇ 10.
  • D is 0.01 to 0.3. In some embodiments, D is 0.03 to 0.2. In some embodiments, D is 0.01, 0.03, 0.05, 0.07, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, or within a range of any of the above.
  • B/D is 1.2, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, or any number above within the range of composition.
  • the impedance, cycle performance, and high-temperature storage performance of the electrochemical device under high-voltage operating conditions can be further improved.
  • the positive active material includes first particles and second particles, the average particle diameter of the first particles is larger than the average particle diameter of the second particles.
  • the first particles comprise primary particles.
  • the second particles are secondary particles.
  • the second particles are polycrystalline particles. The combined use of larger-sized primary particles and smaller-sized secondary particles helps to increase the compaction density of the cathode active material layer, while further improving the impedance, cycling performance, and high-temperature storage performance of electrochemical devices under high-voltage operating conditions .
  • the positive active material satisfies at least one of the following conditions: (i) the Dv50 of the first particles is 10 ⁇ m to 15 ⁇ m; (j) the Dv99 of the first particles is 20 ⁇ m to 30 ⁇ m; (k) Dv50 and Dv99 of the first particles satisfy: 1.5 ⁇ Dv99/Dv50 ⁇ 3; (l) Dv50' of the second particles is 2 ⁇ m to 6 ⁇ m; or (m) Dv50 and The Dv50' of the second particles satisfies: 2 ⁇ Dv50/Dv50' ⁇ 8.
  • the Dv50 of the first particle is 12 ⁇ m to 14 ⁇ m. In some embodiments, the first particle has a Dv50 of 10 ⁇ m, 11 ⁇ m, 12 ⁇ m, 13 ⁇ m, 14 ⁇ m, 15 ⁇ m, or a range consisting of any of the above values.
  • the Dv99 of the first particle is 22 ⁇ m to 28 ⁇ m. In some embodiments, the Dv99 of the first particle is 24 ⁇ m to 26 ⁇ m. In some embodiments, the Dv90 of the first particle is 20 ⁇ m, 21 ⁇ m, 22 ⁇ m, 23 ⁇ m, 24 ⁇ m, 25 ⁇ m, 26 ⁇ m, 27 ⁇ m, 28 ⁇ m, 29 ⁇ m, 30 ⁇ m, or a range consisting of any of the above values.
  • the Dv50 and Dv99 of the first particles satisfy 2.0 ⁇ Dv99/Dv50 ⁇ 2.6. In some embodiments, the Dv99/Dv50 of the first particle is 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9 or any value above In the range.
  • the Dv50' of the second particle is 3 ⁇ m to 5 ⁇ m. In some embodiments, the Dv50' of the second particle is 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, or a range consisting of any of the above values.
  • the Dv50 of the first particle and the Dv50' of the second particle satisfy: 2 ⁇ Dv50/Dv50' ⁇ 7.
  • the ratio Dv50/Dv50' of the Dv50 of the first particle to the Dv50' of the second particle is 2, 3, 4, 5, 6, 7 or a range consisting of any of the above values .
  • the impedance, cycle performance and high temperature storage performance of the electrochemical device under high voltage working conditions can be further improved.
  • the second particles include secondary particles, and the primary particles forming the secondary particles have an average particle diameter of 0.1 ⁇ m to 3 ⁇ m. In some embodiments, the primary particles forming the secondary particles have an average particle diameter of 0.5 ⁇ m to 2 ⁇ m. In some embodiments, the primary particles forming the secondary particles have an average particle diameter of 1 ⁇ m to 1.5 ⁇ m. In some embodiments, the primary particles forming the secondary particles have an average particle size of 0.1 ⁇ m, 0.5 ⁇ m, 1 ⁇ m, 1.5 ⁇ m, 2 ⁇ m, 2.5 ⁇ m, 3 ⁇ m, or within a range consisting of any of the above values.
  • the secondary particles in the second particles are formed of primary particles having the above-mentioned average particle diameter, the impedance, cycle performance and high temperature storage performance of the electrochemical device under high voltage operating conditions can be further improved.
  • the particle size of the primary particles in the second particles can be controlled by controlling the particle size of the raw material or by controlling the sintering temperature and/or the sintering time during the preparation of the secondary particles.
  • the content of lanthanum in the first particles is less than the content of lanthanum in the second particles.
  • the content of lanthanum in the first particles is E wt %
  • the content of lanthanum in the second particles is F wt %
  • E is 0.01 to 0.6
  • F is 0.01 to 0.9.
  • E is 0.01 to 0.5.
  • E is 0.05 to 0.4.
  • E is 0.1 to 0.2.
  • E is 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, or within a range of any of the above.
  • F is 0.01 to 0.4.
  • F is 0.05 to 0.3.
  • F is 0.1 to 0.2. In some embodiments, F is 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, or within a range of any of the above. When the content of lanthanum in the first particles and the second particles is within the above range, the resistance, cycle performance and high temperature storage performance of the electrochemical device under high voltage operating conditions can be further improved.
  • the positive electrode active material has a peak intensity ratio of the strongest peak in the range of 23.0°-24.0° to the strongest peak in the range of 32.5°-33.5° of 0.6 to 1.5 using XRD testing. New characteristic peaks appeared in the range of 23.0°-24.0° and 32.5°-33.5° in the cathode active material, indicating the existence of new phases in the cathode active material.
  • the positive active material includes at least one of cobalt lithium oxide, manganese lithium oxide, or nickel cobalt manganese lithium oxide.
  • the cobalt lithium oxide comprises Li a Co b M c M 2 d O 2 , wherein 0.90 ⁇ a ⁇ 1.2, 0.9 ⁇ b ⁇ 1, 0 ⁇ c ⁇ 0.1, 0 ⁇ d ⁇ 0.1, M contains aluminum and at least one of lanthanum, nickel, manganese, magnesium, titanium, zirconium, fluorine, tungsten, boron, or yttrium, and M2 contains at least one of sodium, iron, silicon, zinc, or phosphorus.
  • the manganese lithium oxide comprises Li a Mn b M c M 2 d O 2 , wherein 0.90 ⁇ a ⁇ 1.8, 0.9 ⁇ b ⁇ 1, 0 ⁇ c ⁇ 0.1, 0 ⁇ d ⁇ 0.1, M Contains aluminum and at least one of lanthanum, nickel, manganese, magnesium, titanium, zirconium, fluorine, tungsten, boron, or yttrium, and M2 contains at least one of sodium, iron, silicon, zinc, or phosphorus.
  • the nickel cobalt manganese lithium oxide comprises Li a Ni b Co c Mn d Me O 2 , wherein 0.90 ⁇ a ⁇ 1.2 , 0 ⁇ b ⁇ 0.95, 0 ⁇ c ⁇ 0.4, 0 ⁇ d ⁇ 0.4, 0 ⁇ e ⁇ 0.1, M contains aluminum and at least one of lanthanum, magnesium, titanium, zirconium, fluorine, tungsten, boron, or yttrium.
  • the molar ratio of the lithium element in the positive electrode active material will be lost during the electrochemical device formation process, resulting in a decrease in the molar ratio of the lithium element.
  • the positive electrode material further includes a binder, and optionally a positive electrode conductive material.
  • the binder can improve the bonding of the positive electrode active material particles to each other, and can also improve the bonding of the positive electrode active material and the positive electrode current collector.
  • binders include polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene , polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylic (esterified) styrene-butadiene rubber, epoxy resin, nylon, etc.
  • the positive electrode material further includes a positive electrode conductive material, thereby imparting electrical conductivity to the electrode.
  • the positive electrode conductive material may include any conductive material as long as it does not cause chemical changes.
  • Non-limiting examples of positive conductive materials include carbon-based materials (eg, natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, etc.), metal-based materials (eg, metal powder, metal fiber, etc., These include, for example, copper, nickel, aluminum, silver, etc.), conductive polymers (eg, polyphenylene derivatives), and mixtures thereof.
  • the positive electrode current collector may be aluminum (Al), but is not limited thereto.
  • the present application also provides a method for preparing the positive electrode active material described in the present application, which includes: step S1: sintering a mixture including a positive electrode active material precursor material at a temperature of 600°C to 1500°C to obtain a primary positive electrode active material Material X; Step S2: sintering the raw material including the primary positive electrode active material X and the compound containing aluminum element at a temperature of 600°C to 1000°C to obtain a positive electrode active material.
  • step S1 sintering a mixture including a positive electrode active material precursor material at a temperature of 600°C to 1500°C to obtain a primary positive electrode active material Material X
  • Step S2 sintering the raw material including the primary positive electrode active material X and the compound containing aluminum element at a temperature of 600°C to 1000°C to obtain a positive electrode active material.
  • the present application also provides a method for preparing the positive electrode active material described in the present application, comprising:
  • Step S1-1 sintering the first mixture including the first cathode active material precursor material at a temperature T1 to obtain a first primary cathode active material X1;
  • Step S2-1 sintering the first raw material including the first primary cathode active material X1 and the first compound containing aluminum element at temperature T1' to obtain first particles;
  • Step S1-2 sintering the second mixture including the second cathode active material precursor material at a temperature T2 to obtain a second primary cathode active material X2;
  • Step S2-2 sintering the second raw material including the second primary cathode active material X2 and the second compound containing aluminum element at temperature T2' to obtain second particles;
  • Step S3 mixing the first particles and the second particles to obtain the positive electrode active material.
  • the sintering time is 4 hours to 12 hours.
  • the temperature T1 is 800°C to 1150°C.
  • step S1-1 the sintering time is 8 to 24 hours.
  • the temperature T1' is 700°C to 1000°C.
  • step S2-1 the sintering time is 4 to 12 hours.
  • the temperature T2 is 800°C to 1050°C.
  • step S1-2 the sintering time is 8 to 24 hours.
  • step S2-2 the temperature T2' is 600°C to 950°C.
  • step S2-2 the sintering time is 4 to 12 hours.
  • At least one of the mixture, the first mixture, or the second mixture optionally includes a compound having aluminum, magnesium, titanium, zirconium, or yttrium.
  • At least one of the mixture, the first mixture, or the second mixture further includes an elemental aluminum-containing compound.
  • At least one of the mixture, the first mixture, or the second mixture includes aluminum element, and optionally a compound having magnesium element, titanium element, zirconium element, or yttrium element.
  • At least one of the feedstock, the first feedstock, or the second feedstock optionally includes at least one element of nickel, manganese, magnesium, titanium, zirconium, fluorine, or yttrium.
  • At least one of the feedstock, the first feedstock, or the second feedstock optionally includes elements having nickel, manganese, magnesium, titanium, zirconium, fluorine, or yttrium compound of elements.
  • At least one of the mixture, the first mixture, or the second mixture further includes a lanthanum-containing compound.
  • Lanthanum tends to thermally diffuse to the particle surface at certain high temperatures, so that the surface region of the positive electrode active material has a greater lanthanum content than the inner region.
  • the lanthanum is present in an amount of 0.01% to 5% based on the weight of the mixture, the first mixture, or the second mixture. In some embodiments, the content of lanthanum is 0.05% to 3%. In some embodiments, the content of lanthanum is 0.1% to 2%. In some embodiments, the content of lanthanum is 0.5% to 1%.
  • At least one of the mixture, the first mixture, or the second mixture further includes a compound containing an element M, the element M including at least one of the following elements: lithium, cobalt, Nickel, Manganese, Magnesium, Titanium, Zirconium, Fluorine, Yttrium, Niobium, Boron, Molybdenum, Vanadium and Cerium.
  • At least one of the mixture, the first mixture, or the second mixture further includes a compound containing an element M, the element M including lithium, cobalt, and at least one of the following elements: Lithium, cobalt, nickel, manganese, magnesium, titanium, zirconium, fluorine, yttrium, niobium, boron, molybdenum, vanadium and cerium.
  • At least one of the mixture, the first mixture, or the second mixture further includes a compound containing an M element, the M element including at least one of the following elements: magnesium, titanium, Zirconium, Fluorine, Yttrium, Niobium, Boron, Molybdenum, Vanadium and Cerium.
  • At least one of the raw material, the first raw material, or the second raw material further includes a compound containing an M element, the M element including at least one of the following elements: lithium, cobalt, Nickel, Manganese, Magnesium, Titanium, Zirconium, Fluorine, Yttrium, Niobium, Boron, Molybdenum, Vanadium and Cerium.
  • At least one of the feedstock, the first feedstock, or the second feedstock further includes a compound containing an M element, the M element including lithium, cobalt, and at least one of the following elements: Lithium, cobalt, nickel, manganese, magnesium, titanium, zirconium, fluorine, yttrium, niobium, boron, molybdenum, vanadium and cerium.
  • the compound containing M element is at least one of M element oxide, M element hydroxide, M element carbonate, M element phosphate, or M element fluoride .
  • At least one of the cathode active material precursor material, the first cathode active material precursor material, and the second cathode active material precursor material includes a cobalt-containing compound and a lithium salt .
  • the compound containing cobalt element includes at least one of cobalt oxide or cobalt hydroxide.
  • the lithium salt includes at least one of lithium carbonate, lithium oxide, or lithium hydroxide.
  • the molar ratio of the compound containing cobalt element to the lithium salt is 0.90:1 to 1.1:1.
  • the molar ratio of the compound containing cobalt element to the lithium salt is 0.90:1 to 1.08:1.
  • the first particles and the second particles are mixed in a mass ratio of 1:9 to 9:1 to obtain the positive electrode active material. In some embodiments, in the step S3, the first particles and the second particles are mixed in a mass ratio of 2:8 to 8:2. In some embodiments, in the step S3, the first particles and the second particles are mixed in a mass ratio of 3:7 to 7:3. In some embodiments, in the step S3, the first particles and the second particles are mixed in a mass ratio of 4:6 to 6:4. In some embodiments, in the step S3, the first particles and the second particles are mixed in a mass ratio of 5:5.
  • the negative electrode includes a current collector and a negative electrode active material layer disposed on the current collector.
  • the specific types of negative electrode active materials are not specifically limited, and can be selected according to requirements.
  • the negative electrode active material is selected from natural graphite, artificial graphite, mesophase microcarbon spheres (abbreviated as MCMB), hard carbon, soft carbon, silicon, silicon-carbon composite, Li-Sn alloy, Li -One or more of Sn-O alloy, Sn, SnO, SnO 2 , spinel structure lithiated TiO 2 -Li 4 Ti 5 O 12 , and Li-Al alloy.
  • MCMB mesophase microcarbon spheres
  • Non-limiting examples of carbon materials include crystalline carbon, amorphous carbon, and mixtures thereof.
  • Crystalline carbon can be amorphous or flake-shaped, platelet-shaped, spherical or fibrous natural graphite or artificial graphite.
  • the amorphous carbon can be soft carbon, hard carbon, mesophase pitch carbide, calcined coke, and the like.
  • the anode active material layer may include a binder, and optionally a conductive material.
  • binders include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene-containing Oxygen polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylic (esterified) styrene-butadiene rubber, epoxy resin, Nylon etc.
  • the negative electrode active material layer includes a conductive material, thereby imparting conductivity to the electrode.
  • the conductive material may include any conductive material as long as it does not cause chemical changes.
  • Non-limiting examples of conductive materials include carbon-based materials (eg, natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, etc.), metal-based materials (eg, metal powders, metal fibers, etc., such as copper, nickel, aluminum, silver, etc.), conductive polymers (eg, polyphenylene derivatives), and mixtures thereof.
  • the current collector for the negative electrode described herein may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, conductive metal clad polymer substrates, and combinations thereof.
  • Lithium salts that can be used in the electrolyte of the embodiments of the present application include, but are not limited to, inorganic lithium salts, such as LiClO 4 , LiAsF 6 , LiPF 6 , LiBF 4 , LiSbF 6 , LiSO 3 F, LiN(FSO 2 ) 2 , etc.
  • inorganic lithium salts such as LiClO 4 , LiAsF 6 , LiPF 6 , LiBF 4 , LiSbF 6 , LiSO 3 F, LiN(FSO 2 ) 2 , etc.
  • Fluorine-containing organolithium salts such as LiCF 3 SO 3 , LiN(FSO 2 )(CF 3 SO 2 ), LiN(CF 3 SO 2 ) 2 , LiN(C 2 F 5 SO 2 ) 2 , cyclic 1,3 -Lithium hexafluoropropanedisulfonimide, Lithium cyclic 1,2-tetrafluoroethanedisulfonimide, LiN(CF 3 SO 2 )(C 4 F 9 SO 2 ), LiC(CF 3 SO 2 ) ) 3 , LiPF 4 (CF 3 ) 2 , LiPF 4 (C 2 F 5 ) 2 , LiPF 4 (CF 3 SO 2 ) 2 , LiPF 4 (C 2 F 5 SO 2 ) 2 , LiBF 2 (CF 3 ) 2 , LiBF2(C2F5)2, LiBF 2 (CF 3 SO 2 ) 2 , LiBF 2 (C 2 F 5 SO 2 ) 2 ; lithium salts containing di
  • the lithium salts may be used alone, or two or more of them may be used in combination.
  • the lithium salt includes a combination of LiPF 6 and LiBF 4 .
  • the lithium salt includes an inorganic lithium salt such as LiPF 6 or LiBF 4 and a fluorine-containing organolithium salt such as LiCF 3 SO 3 , LiN(CF 3 SO 2 ) 2 , LiN(C 2 F 5 SO 2 ) 2 , etc. combination.
  • the concentration of the lithium salt is in the range of 0.8 mol/L to 3 mol/L, in the range of 0.8 mol/L to 2.5 mol/L, in the range of 0.8 mol/L to 2 mol/L, or 1 mol/L to the range of 2 mol/L. In some embodiments, the concentration of the lithium salt is about 1 mol/L, about 1.15 mol/L, about 1.2 mol/L, about 1.5 mol/L, about 2 mol/L, or about 2.5 mol/L.
  • Solvents that can be used in the electrolyte of the embodiments of the present application include, but are not limited to: cyclic carbonate, chain carbonate, cyclic carboxylate, chain carboxylate, cyclic ether, chain ether, phosphorus-containing Organic solvents, sulfur-containing organic solvents and aromatic fluorinated solvents.
  • cyclic carbonates include, but are not limited to: ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate. In some embodiments, the cyclic carbonate has 3-6 carbon atoms.
  • chain carbonates include, but are not limited to: dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate (DEC), methyl-n-propyl carbonate, ethyl-n-propyl carbonate
  • Chain carbonates such as base ester and di-n-propyl carbonate, as chain carbonates substituted by fluorine, such as bis(fluoromethyl)carbonate, bis(difluoromethyl)carbonate, bis(trifluoromethyl)carbonate ) carbonate, bis(2-fluoroethyl)carbonate, bis(2,2-difluoroethyl)carbonate, bis(2,2,2-trifluoroethyl)carbonate, 2-fluoroethyl Methyl carbonate, 2,2-difluoroethyl methyl carbonate and 2,2,2-trifluoroethyl methyl carbonate.
  • cyclic carboxylic acid esters include, but are not limited to: gamma-butyrolactone and gamma-valerolactone.
  • some of the hydrogen atoms of the cyclic carboxylate may be replaced by fluorine.
  • chain carboxylates include, but are not limited to: methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, sec-butyl acetate, isobutyl acetate, tert-butyl acetate Butyl, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, methyl isobutyrate, ethyl isobutyrate , methyl valerate, ethyl valerate, methyl pivalate and ethyl pivalate.
  • fluorine-substituted chain carboxylates include, but are not limited to: methyl trifluoroacetate, ethyl trifluoroacetate, propyl trifluoroacetate, butyl trifluoroacetate, and 2,2 trifluoroacetate , 2-trifluoroethyl ester.
  • cyclic ethers include, but are not limited to: tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 2-methyl 1,3-dioxolane, 4-methyl 1 , 3-dioxolane, 1,3-dioxane, 1,4-dioxane and dimethoxypropane.
  • chain ethers include, but are not limited to: dimethoxymethane, 1,1-dimethoxyethane, 1,2-dimethoxyethane, diethoxymethane, 1 ,1-diethoxyethane, 1,2-diethoxyethane, ethoxymethoxymethane, 1,1-ethoxymethoxyethane and 1,2-ethoxymethyl oxyethane.
  • phosphorus-containing organic solvents include, but are not limited to: trimethyl phosphate, triethyl phosphate, dimethyl ethyl phosphate, methyl diethyl phosphate, ethylene methyl phosphate, ethylene phosphate Ethyl ethyl, triphenyl phosphate, trimethyl phosphite, triethyl phosphite, triphenyl phosphite, tris(2,2,2-trifluoroethyl) phosphate and tris(2,2, phosphate) 3,3,3-pentafluoropropyl) ester.
  • sulfur-containing organic solvents include, but are not limited to: sulfolane, 2-methyl sulfolane, 3-methyl sulfolane, dimethyl sulfone, diethyl sulfone, ethyl methyl sulfone, methyl propyl sulfone Sulfone, dimethyl sulfoxide, methyl methanesulfonate, ethyl methanesulfonate, methyl ethanesulfonate, ethyl ethanesulfonate, dimethyl sulfate, diethyl sulfate, and dibutyl sulfate.
  • some of the hydrogen atoms of the sulfur-containing organic solvent may be replaced by fluorine.
  • aromatic fluorine-containing solvents include, but are not limited to: fluorobenzene, difluorobenzene, trifluorobenzene, tetrafluorobenzene, pentafluorobenzene, hexafluorobenzene, and trifluoromethylbenzene.
  • the solvent used in the electrolyte of the present application includes one or more of the above.
  • the solvent used in the electrolyte of the present application includes cyclic carbonate, chain carbonate, cyclic carboxylate, chain carboxylate, and combinations thereof.
  • the solvent used in the electrolyte of the present application comprises an organic solvent selected from the group consisting of: ethylene carbonate, propylene carbonate, diethyl carbonate, ethyl propionate, propionic acid Propyl ester, n-propyl acetate, ethyl acetate, and combinations thereof.
  • the solvent used in the electrolyte of the present application comprises: ethylene carbonate, propylene carbonate, diethyl carbonate, ethyl propionate, propyl propionate, ⁇ -butyrolactone or a combination thereof .
  • the additives that can be used in the electrolyte of the embodiments of the present application include, but are not limited to: compounds with 2-3 cyano groups, cyclic carbonates containing carbon-carbon double bonds, compounds containing sulfur-oxygen double bonds, difluorophosphoric acid lithium.
  • compounds with 2-3 cyano groups may include compounds selected from the group consisting of succinonitrile (SN), adiponitrile (ADN), ethylene glycol bis(propionitrile) ether (EDN), 1,3, 5-pentanetricarbonitrile, 1,2,3-propanetricarbonitrile, 1,3,6-hexanetricarbonitrile (HTCN), 1,2,6-hexanetricarbonitrile, 1,2,3-tris(2 - at least one of cyanoethoxy)propane (TCEP) or 1,2,4-tris(2-cyanoethoxy)butane; based on the total weight of the electrolyte, the The content of the compound with 3 cyano groups is 0.1%-10%.
  • Cyclic carbonates with carbon-carbon double bonds in some embodiments specifically include, but are not limited to: vinylene carbonate, methyl vinylene carbonate, ethyl vinylene carbonate, vinyl vinyl ethylene carbonate or At least one of 1,2-dimethyl vinylene carbonate.
  • Compounds containing sulfur-oxygen double bonds in some embodiments include, but are not limited to: vinyl sulfate, 1,2-propanediol sulfate, 1,3-propanesultone, 1-fluoro-1,3-propanesulfonate At least one of acid lactone, 2-fluoro-1,3-propane sultone or 3-fluoro-1,3-propane sultone.
  • a separator can be provided between the positive electrode and the negative electrode to prevent short circuit.
  • the material and shape of the isolation membrane that can be used in the embodiments of the present application are not particularly limited, and may be any of the techniques disclosed in the prior art.
  • the separator includes a polymer or inorganic or the like formed from a material that is stable to the electrolyte of the present application.
  • the release film may include a substrate layer and a surface treatment layer.
  • the base material layer is a non-woven fabric, film or composite film with a porous structure, and the material of the base material layer is selected from at least one of polyethylene, polypropylene, polyethylene terephthalate and polyimide.
  • a polypropylene porous membrane, a polyethylene porous membrane, a polypropylene non-woven fabric, a polyethylene non-woven fabric or a polypropylene-polyethylene-polypropylene porous composite membrane can be selected.
  • At least one surface of the base material layer is provided with a surface treatment layer, and the surface treatment layer may be a polymer layer or an inorganic material layer, or a layer formed by mixing a polymer and an inorganic material.
  • the inorganic layer includes inorganic particles and a binder, and the inorganic particles are selected from aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium oxide, tin oxide, ceria, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, One or a combination of yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide and barium sulfate.
  • the binder is selected from polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, One or a combination of polymethyl methacrylate, polytetrafluoroethylene and polyhexafluoropropylene.
  • the polymer layer contains a polymer, and the material of the polymer is selected from polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride, polyvinylidene At least one of (vinylidene fluoride-hexafluoropropylene).
  • the electrochemical device of the present application includes any device in which an electrochemical reaction occurs, and specific examples thereof include all kinds of primary batteries or secondary batteries.
  • the lithium secondary battery may include a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery.
  • the present application further provides an electronic device comprising the electrochemical device according to the present application.
  • the use of the electrochemical device of the present application is not particularly limited, and it can be used in any electronic device known in the art.
  • the electrochemical devices of the present application may be used in, 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 stereo headphones, VCRs, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power, motors, cars, motorcycles, power Bicycles, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries and lithium-ion capacitors, etc.
  • lithium ion batteries The preparation of lithium ion batteries is described below by taking lithium ion batteries as an example and in conjunction with specific embodiments. Those skilled in the art will understand that the preparation methods described in this application are only examples, and any other suitable preparation methods are included in the scope of this application. within the range.
  • the preparation method is basically the same as that of Comparative Example 2, except that the content of aluminum element in the surface area and the inner area of the positive electrode active material is adjusted by the addition amount of aluminum element to obtain the positive electrode active material.
  • the prepared first particles and the second particles are mixed in a mass ratio of 8:2 to obtain a positive electrode active material.
  • Example 2 Substantially the same preparation method as in Example 1 was adopted, except that the content of the aluminum element in the surface region of the positive electrode active material was adjusted by the addition amount of the aluminum element.
  • Example 4 Substantially the same preparation method as in Example 4 was adopted, except that the content of aluminum element in the surface region and the inner region of the positive electrode active material was adjusted by the addition amount of aluminum element.
  • Example 23 Substantially the same method as in Example 23 was employed, except that the lanthanum content in the surface region of the positive electrode active material was adjusted by the addition amount of lanthanum.
  • Example 34 Substantially the same preparation method as Example 34 was used, except that the content of lanthanum in the inner region, aluminum in the surface region, and lanthanum in the surface region was adjusted by the addition amount of aluminum or lanthanum.
  • first primary positive electrode active material was mixed with 1.4 g of lanthanum oxide, 3.5 g of alumina, and 2.0 g of titanium dioxide, and the mixture was sintered at 800° C. for 12 hours to obtain first particles.
  • the prepared first particles and the second particles are mixed in a mass ratio of 8:2 to obtain a positive electrode active material.
  • Example 48 Substantially the same preparation method was used as in Example 48, except that the first particle Dv50, the first particle Dv99, the second particle Dv50' and/or the particle size of the primary particle in the second particle of the positive electrode active material.
  • Example 48 Substantially the same preparation method as in Example 48 was employed, except that the content of lanthanum in the first particles of the positive electrode active material and/or the content of lanthanum in the first particles was adjusted by the addition amount of lanthanum.
  • the positive electrode active material, acetylene black and polyvinylidene fluoride (PVDF) were dissolved in N-methylpyrrolidone (NMP) according to the weight ratio of 94:3:3, and the positive electrode slurry was obtained by stirring and mixing well.
  • NMP N-methylpyrrolidone
  • the positive electrode slurry is coated on the positive electrode current collector aluminum foil, dried, and cold-pressed to obtain a positive electrode active material layer, which is then cut and welded to obtain a positive electrode.
  • a PE porous polymer film with a thickness of 10 ⁇ m was used as the separator.
  • the positive electrode, separator and negative electrode are stacked in sequence, rolled, placed in the outer package, injected with electrolyte, and packaged.
  • the lithium-ion battery is obtained through the process of formation, degassing, trimming and other processes.
  • the elemental content of the surface area of the sample was tested by the following method: the filtrate was fixed to 200 mL, and the content of aluminum and lanthanum in the filtrate was measured by inductively coupled plasma optical emission spectrometer (ICP-OES).
  • ICP-OES inductively coupled plasma optical emission spectrometer
  • the element content in the inner area of the sample was tested by the following method: adding the filtration residue to 10 mL of aqua regia for complete digestion, diluting the digested solution to 50 mL, and using ICP-OES to test the content of lanthanum in the digestion solution.
  • the lithium ion battery was discharged to a voltage of 3.0V, the positive electrode active material layer was removed from the positive electrode, placed in a muffle furnace, fired at 350°C in an air atmosphere for 4 hours, and the sample was taken out after cooling.
  • the sample was sieved with an 800-mesh sieve to obtain the first particle and the second particle.
  • the powder of the sample to be tested was tested by an X-ray powder diffractometer, and the test was conducted with reference to the JB/T 4220-2011 measurement method, and the XRD spectrum of the sample was obtained after the test.
  • the lithium-ion battery was charged to 3.85V at a constant current rate of 0.5C. After the voltage reached 3.85V, the battery was charged to a constant voltage until the current was lower than 0.025C, and left for 5 minutes. Then use the EIS impedance tester to carry out the alternating current impedance (EIS) test.
  • the frequency range of the EIS test was set to 0.1-10kHz, and the amplitude was set to 5mV.
  • the Rct impedance value of the lithium-ion battery is obtained through the EIS test.
  • the lithium-ion battery was charged at a constant current of 0.5C to a voltage of 4.50V, and then charged at a constant voltage of 4.50V until the current was lower than 0.05C, so that it was in a fully charged state of 4.50V. Test the thickness of the fully charged battery before storage, denoted as D0. Then, the fully charged lithium-ion battery was stored in an oven at 85°C for 24 hours, and the thickness of the lithium-ion battery after storage was measured immediately after taking it out, which was recorded as D1.
  • High-temperature storage expansion ratio (D1-D0)/D0 ⁇ 100%.
  • the lithium-ion battery was charged with constant current to 4.50V at a charge rate of 0.5C, and then charged with constant voltage to 0.025C. After standing for 5 minutes, it was discharged to 3.0V, record the first cycle discharge capacity value. The same procedure was used to charge and discharge the lithium-ion battery 800 times, and the discharge capacity value of the 800th cycle was recorded.
  • the cycle capacity retention rate of the lithium-ion battery was calculated according to the following formula:
  • Cycle capacity retention rate (discharge capacity at the 800th cycle/discharge capacity at the first cycle) ⁇ 100%.
  • Table 1 shows the effects of aluminum elements and their contents in the surface and inner regions of the cathode active material on the impedance, cycle capacity retention, and high-temperature storage expansion ratio of lithium-ion batteries.
  • the positive active material precursor used in each of the Examples and Comparative Examples in Table 1 was lithium cobalt oxide (LiCoO 2 ).
  • the positive active materials used in each of the Examples and Comparative Examples in Table 1 contained only one type of particles, wherein the positive active materials of Comparative Examples 1-4 and Examples 1-21 contained only the first particles (Dv50 was 12 ⁇ m), The positive electrode active materials of Comparative Example 5 and Example 22 contained only the second particles (Dv50' was 4 ⁇ m).
  • the aluminum content of the surface region of the cathode active material plays a crucial role in improving the impedance, high-temperature storage expansion rate, and cycle capacity retention of Li-ion batteries under high-voltage operating conditions.
  • the surface area of the positive electrode active material contains 0.01 wt % to 1 wt % of aluminum element It can effectively ensure the stability of the bulk phase structure of the material and the diffusion kinetics of the surface, comprehensively improve the high-temperature cycle performance and impedance performance of the material, significantly reduce the impedance and high-temperature storage expansion rate of lithium-ion batteries under high-voltage working conditions, and significantly improve Its cycle capacity retention rate.
  • the aluminum element content A in the surface region of the positive electrode active material is 0.01 wt % to 0.4 wt %, the lithium ion battery has remarkably excellent cycle and storage performance.
  • the inner region of the positive electrode active material may further contain aluminum element, which helps to further improve the resistance, high-temperature storage expansion rate, and cycle capacity retention rate of the lithium-ion battery under high-voltage operating conditions.
  • the surface region of the positive electrode active material contains 0.01 wt % to 1 wt % of the aluminum element, when the content A 1 wt % of the aluminum element in the inner region of the positive electrode active material satisfies that A 1 is 0.05 to 2; A 1 >A; And/or when 1 ⁇ A 1 /A ⁇ 10, the impedance and high-temperature storage expansion rate of the lithium-ion battery under high-voltage working conditions can be further reduced, and the cycle capacity retention rate of the lithium-ion battery can be further improved.
  • FIG. 1 shows a scanning electron microscope (SEM) image of the positive electrode active material used in Comparative Example 1, wherein the surface of the positive electrode active material does not contain aluminum element.
  • FIG. 2 shows a scanning electron microscope (SEM) image of the positive electrode active material used in Example 7, wherein the surface of the positive electrode active material contains aluminum element.
  • Table 2 shows the effects of the Al content in the surface area of the cathode active material, the lanthanum content in the surface area and the inner area, and other surface elements on the impedance, cycle capacity retention, and high-temperature storage expansion rate of Li-ion batteries.
  • Examples 23-47 contain only one particle (the first particle), which differs from Example 6 only by the parameters listed in Table 2.
  • the surface region and/or inner region of the positive electrode active material can further contain lanthanum, which can synergize with the aluminum element in the surface region to improve the structural stability of the positive electrode active material, while improving the diffusion and surface impedance of lithium ions .
  • the surface area of the positive electrode active material contains 0.01 wt % to 1 wt % of the aluminum element
  • B wt % in the surface area of the positive electrode active material satisfies that B is 0.01 to 0.8 and/or 0.01 ⁇ B/A ⁇
  • the value is 0.8, it is helpful to further reduce the impedance and high-temperature storage expansion rate of lithium-ion batteries under high-voltage working conditions, and further improve the cycle capacity retention rate of lithium-ion batteries.
  • the lanthanum content in the surface region of the positive electrode active material is in the range of 0.01 wt % to 0.7 wt %, the lithium ion battery has exceptionally excellent cycle and storage performance.
  • the surface region of the positive electrode active material contains 0.01 wt % to 1 wt % of the aluminum element
  • D wt % satisfies D of 0.01 to 0.4
  • B>D satisfies D of 0.01 to 0.4
  • 1 ⁇ B/D ⁇ 10 it is helpful to further reduce the impedance and high-temperature storage expansion rate of the lithium-ion battery under high-voltage working conditions, and further improve the cycle capacity retention rate of the lithium-ion battery.
  • the positive active material surface area may further contain other elements (eg, at least one of lithium, cobalt, nickel, manganese, magnesium, titanium, zirconium, fluorine, or yttrium), which help to further optimize lithium-ion batteries for high voltage operation Impedance, high-temperature storage expansion, and cycling capacity retention under conditions.
  • other elements eg, at least one of lithium, cobalt, nickel, manganese, magnesium, titanium, zirconium, fluorine, or yttrium
  • FIG. 3 shows the X-ray diffraction spectrum (XRD) of the positive electrode active material used in Comparative Example 1 and Example 28, wherein when the surface region of the positive electrode active material contains aluminum element, the positive electrode active material is at 23.0°-24.0° and 32.5° At least two new characteristic peaks appeared in the range of °-33.5°, which indicated the emergence of new phases in the cathode active material.
  • XRD X-ray diffraction spectrum
  • Table 3 shows the effects of the first particle size, the second particle size, and the primary particle size in the second particle of the positive electrode active material on the impedance, cycle capacity retention, and high-temperature storage expansion ratio of the lithium-ion battery.
  • Comparative Example 6 and Examples 48-68 contained two types of particles, namely, a first particle and a second particle. Neither the first particles nor the second particles of the positive electrode active material of Comparative Example 6 contained aluminum element.
  • the surface area of the first particle contained 0.15 wt% aluminum and 0.10 wt% lanthanum, and the interior area contained 0.75 wt% aluminum and 0.07 wt% lanthanum;
  • the surface area of the second particle Contains 0.15wt% aluminum and 0.10wt% lanthanum, and the inner region contains 0.75wt% aluminum and 0.15wt% lanthanum.
  • the results show that when the positive active material satisfies the Dv50 of the first particle in the range of 10 ⁇ m to 15 ⁇ m; the Dv99 of the first particle is in the range of 20 ⁇ m to 30 ⁇ m; the Dv50′ of the second particle is in the range of 2 ⁇ m to 6 ⁇ m; 1.5 ⁇ Dv99 When /Dv50 ⁇ 3; and/or 2 ⁇ Dv50/Dv50' ⁇ 8, the impedance, high-temperature storage expansion rate and cycle capacity retention rate of the lithium-ion battery under high-voltage working conditions can be further improved.
  • the second particles of the positive electrode active material contain secondary particles and the average particle diameter of the primary particles forming the secondary particles is 0.1 ⁇ m to 3 ⁇ m, it is helpful to further improve the resistance of the lithium ion battery under high voltage operating conditions, high temperature storage Expansion and Cyclic Capacity Retention.
  • Table 4 shows the content of lanthanum in the first particle of the positive electrode active material, the content of lanthanum in the second particle, and the strongest peak in the range of 23.0°-24.0° and the strongest peak in the range of 32.5°-33.5° of the positive electrode active material The effect of peak intensity ratio of peaks on the impedance, cycle capacity retention and high temperature storage expansion ratio of Li-ion batteries.
  • Examples 69-86 contain two particles (a first particle and a second particle), which differ from Example 65 only by the parameters listed in Table 3.
  • the lithium-ion battery can be further improved at high voltage Impedance, high temperature storage expansion and cycling capacity retention under operating conditions.
  • E wt% and the content of lanthanum in the second particles (F wt%) satisfy 0.5 ⁇ E/F ⁇ 1, it is helpful to further improve the high voltage of lithium-ion batteries. Impedance, high temperature storage expansion and cycling capacity retention under operating conditions.
  • the peak-intensity ratio of the strongest peak in the range of 23.0°-24.0° and the strongest peak in the range of 32.5°-33.5° of the cathode active material is in the range of 0.6 to 1.5, a more effective lanthanum-containing surface is formed on the surface of the material.
  • the ion conductor coating layer can further optimize the impedance, high temperature storage expansion rate and cycle capacity retention rate of lithium ion batteries under high voltage operating conditions.

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Abstract

本申请涉及一种正极活性材料及使用其的电化学装置和电子装置。具体而言，本申请提供一种正极活性材料，所述正极活性材料的表面区域的至少一部分包含特定含量的铝元素。本申请的正极材料有助于改善电化学装置在高电压工作条件下的阻抗、循环性能和高温存储性能。

Description

正极活性材料及使用其的电化学装置和电子装置 技术领域
本申请涉及储能领域，具体涉及一种正极活性材料及使用其的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)由于具有高能量密度、高安全性、无记忆效应、工作寿命长等优点已广泛应用于消费类电子产品，例如，笔记本电脑、手机、掌上游戏机、平板电脑、移动电源和无人机等。随着此类电子产品的需求的提高，人们对电化学装置的要求也越来越高，包括其便携性、容量、循环性能、存储性能、工作寿命和快速充电性能等。如何提高电化学装置的快速充电性能已成为研发重点方向之一。开发新型正极活性材料是改善电化学装置的快速充电性能的方式之一。然而，传统正极活性材料在高电压工作条件下仍面临诸多问题，在应用上受到很大限制。
有鉴于此，确有必要提供一种具有改进的高电压工作性能的正极活性材料。
发明内容
本申请通过提供一种适于在高电压工作条件下使用的正极活性材料以试图在至少某种程度上解决至少一种存在于相关领域中的问题。
根据本申请的一个方面，本申请提供了一种正极活性材料，所述正极活性材料的表面区域的至少一部分包含铝元素，基于所述正极活性材料的重量，所述表面区域中的所述铝元素的含量为A wt％，A为0.01至1。
根据本申请的实施例，所述正极活性材料的内部区域包含铝元素，基于所述正极活性材料的重量，所述内部区域中的所述铝元素的含量为A 1wt％，A 1满足以下条件中的至少一者：(a)A 1为0.05至2；(b)A 1＞A；(c)1＜A 1/A＜10。
根据本申请的实施例，所述正极活性材料的表面区域的至少一部分进一步包含镧元素，基于所述正极活性材料的重量，所述表面的至少一部分区域中的所述镧元素的含量为B wt％，B满足以下条件中的至少一者：(d)B为0.01至0.8；(e)0.01≤B/A≤0.8。
根据本申请的实施例，所述正极活性材料的表面区域的至少一部分进一步包含锂、 钴、镍、锰、镁、钛、锆、氟或钇中的至少一种元素。
根据本申请的实施例，所述正极活性材料的内部区域包含镧元素，基于所述正极活性材料的重量，所述内部区域中的所述镧元素的含量为D wt％，D满足以下条件中的至少一者：(f)D为0.01至0.4；(g)B＞D；(h)1＜B/D＜10。
根据本申请的实施例，所述正极活性材料包含第一颗粒和第二颗粒，所述第一颗粒的平均粒径大于所述第二颗粒的平均粒径。
根据本申请的实施例，所述正极活性材料满足以下条件中的至少一者：(i)所述第一颗粒的Dv50为10μm至15μm；(j)所述第一颗粒的Dv99为20μm至30μm；(k)所述第一颗粒的Dv50与Dv99满足：1.5≤Dv99/Dv50＜3；(l)所述第二颗粒的Dv50'为2μm至6μm；或(m)所述第一颗粒的Dv50与所述第二颗粒的Dv50'满足：2≤Dv50/Dv50'＜8。
根据本申请的实施例，所述第二颗粒包含二次颗粒，形成所述二次颗粒的一次颗粒的平均粒径为0.1μm至3μm。
根据本申请的实施例，所述第二颗粒为多晶颗粒。
根据本申请的实施例，所述第一颗粒中镧元素的含量小于所述第二颗粒中镧元素的含量。
根据本申请的实施例，基于所述正极活性材料的重量，所述第一颗粒中镧元素的含量为E wt％，所述第二颗粒中镧元素的含量为F wt％，E为0.01至0.6，F为0.01至0.9。
根据本申请的实施例，0.5≤E/F＜1。
根据本申请的实施例，采用XRD测试，所述正极活性材料在23.0°-24.0°范围内的最强峰与32.5°-33.5°范围内的最强峰的峰强比为0.6至1.5。
根据本申请的实施例，所述正极活性材料包括钴锂氧化物、锰锂氧化物、或镍钴锰锂氧化物中的至少一种。
根据本申请的另一个方面，本申请提供了一种制备本申请所述的正极活性材料的方法，其包括：
步骤S1：将包括正极活性材料前体材料的混合物在600℃至1500℃的温度下烧结，得到初级正极活性材料X；
步骤S2：将包括所述初级正极活性材料X与含有铝元素的化合物的原料在600℃至1000℃的温度下烧结，得到正极活性材料。
根据本申请的另一个方面，本申请还提供了一种制备本申请所述的正极活性材料的 方法，其包括：
步骤S1-1：将包括第一正极活性材料前体材料的第一混合物在温度T1下烧结，得到第一初级正极活性材料X1；
步骤S2-1：将包括所述第一初级正极活性材料X1与含有铝元素的第一化合物的第一原料在温度T1'下烧结，得到第一颗粒；
步骤S1-2：将包括第二正极活性材料前体材料的第二混合物在温度T2下烧结，得到第二初级正极活性材料X2；
步骤S2-2：将包括所述第二初级正极活性材料X2与含有铝元素的第二化合物的第二原料在温度T2'下烧结，得到第二颗粒；
步骤S3：混合所述第一颗粒和所述第二颗粒，得到所述正极活性材料。
根据本申请的实施例，在步骤S1、S2、S1-1、S2-1、S1-2或S2-2中的至少一者中，烧结时间为4小时至12小时。
根据本申请的实施例，在步骤S1-1中，所述温度T1为800℃至1150℃。
根据本申请的实施例，在步骤S1-1中，烧结时间为8至24小时。
根据本申请的实施例，在步骤S2-1中，所述温度T1'为700℃至1000℃。
根据本申请的实施例，在步骤S2-1中，烧结时间为4至12小时。
根据本申请的实施例，在步骤S1-2中，所述温度T2为800℃至1050℃。
根据本申请的实施例，在步骤S1-2中，烧结时间为8至24小时。
根据本申请的实施例，在步骤S2-2中，所述温度T2'为600℃至950℃。
根据本申请的实施例，在步骤S2-2中，烧结时间为4至12小时。
根据本申请的实施例，所述混合物、所述第一混合物或所述第二混合物的至少一者任选地包含具有铝元素、镁元素、钛元素、锆元素或钇元素的化合物。
根据本申请的实施例，所述混合物、所述第一混合物或所述第二混合物的至少一者进一步包括含有铝元素的化合物。
根据本申请的实施例，所述混合物、所述第一混合物或所述第二混合物的至少一者包含铝元素，以及任选地包含具有镁元素、钛元素、锆元素或钇元素的化合物。
根据本申请的实施例，所述原料、所述第一原料或所述第二原料中的至少一者任选地包括镍、锰、镁、钛、锆、氟或钇中的至少一种元素。
根据本申请的实施例，所述原料、所述第一原料或所述第二原料中的至少一者任选地包括具有镍元素、锰元素、镁元素、钛元素、锆元素、氟元素或钇元素的化合物。
根据本申请的实施例，所述混合物、所述第一混合物或所述第二混合物的至少一者进一步包括含有镧元素的化合物。
根据本申请的实施例，基于所述混合物、所述第一混合物或所述第二混合物的重量，所述镧元素的含量为0.01％至5％。
根据本申请的实施例，所述混合物、所述第一混合物或所述第二混合物的至少一者进一步包括含有M元素的化合物，所述M元素包括以下元素中的至少一种：锂、钴、镍、锰、镁、钛、锆、氟、钇、铌、硼、钼、钒和铈。
根据本申请的实施例，所述混合物、所述第一混合物或所述第二混合物的至少一者进一步包括含有M元素的化合物，所述M元素包括锂、钴以及以下元素中的至少一种：锂、钴、镍、锰、镁、钛、锆、氟、钇、铌、硼、钼、钒和铈。
根据本申请的实施例，所述混合物、所述第一混合物或所述第二混合物的至少一者进一步包括含有M元素的化合物，所述M元素包括以下元素中的至少一种：镁、钛、锆、氟、钇、铌、硼、钼、钒和铈。
根据本申请的实施例，所述原料、所述第一原料或所述第二原料的至少一者进一步包括含有M元素的化合物，所述M元素包括以下元素中的至少一种：锂、钴、镍、锰、镁、钛、锆、氟、钇、铌、硼、钼、钒和铈。
根据本申请的实施例，所述原料、所述第一原料或所述第二原料的至少一者进一步包括含有M元素的化合物，所述M元素包括锂、钴以及以下元素中的至少一种：锂、钴、镍、锰、镁、钛、锆、氟、钇、铌、硼、钼、钒和铈。
根据本申请的实施例，所述含有M元素的化合物为M元素的氧化物、M元素的氢氧化物、M元素的碳酸盐、M元素的磷酸盐或M元素的氟化物中的至少一种。
根据本申请的实施例，所述正极活性材料前体材料、所述第一正极活性材料前体材料和所述第二正极活性材料前体材料中的至少一种包括含有钴元素的化合物和锂盐。
根据本申请的实施例，所述含有钴元素的化合物包括氧化钴或氢氧化钴中的至少一种。
根据本申请的实施例，所述锂盐包括碳酸锂、氧化锂或氢氧化锂中的至少一种。
根据本申请的实施例，所述含有钴元素的化合物与所述锂盐的摩尔比为0.90:1至1.1:1。
根据本申请的实施例，在所述步骤S3中，所述第一颗粒和所述第二颗粒按照1:9至9:1的质量比混合，得到所述正极活性材料。
根据本申请的另一个方面，本申请提供了一种电化学装置，其包括正极、负极和电解液，其中所述正极包括根据本申请实施例的正极活性材料。
根据本申请的又一个方面，本申请提供了一种电子装置，其包括根据本申请实施例的电化学装置。
本申请的额外层面及优点将部分地在后续说明中描述、显示、或是经由本申请实施例的实施而阐释。
附图说明
在下文中将简要地说明为了描述本申请实施例或现有技术所必要的附图以便于描述本申请的实施例。显而易见地，下文描述中的附图仅只是本申请中的部分实施例。对本领域技术人员而言，在不需要创造性劳动的前提下，依然可以根据这些附图中所例示的结构来获得其他实施例的附图。
图1展示了对比例1中使用的正极活性材料的电子扫描显微镜(SEM)图。
图2展示了实施例7中使用的正极活性材料的电子扫描显微镜(SEM)图。
图3展示了对比例1和实施例28中使用的正极活性材料的X射线衍射谱(XRD)。
具体实施方式
本申请的实施例将会被详细的描示在下文中。本申请的实施例不应该被解释为对本申请的限制。
如本文中所使用，术语“约”用以描述及说明小的变化。当与事件或情形结合使用时，所述术语可指代其中事件或情形精确发生的例子以及其中事件或情形极近似地发生的例子。举例来说，当结合数值使用时，术语可指代小于或等于所述数值的±10％的变化范围，例如小于或等于±5％、小于或等于±4％、小于或等于±3％、小于或等于±2％、小于或等于±1％、小于或等于±0.5％、小于或等于±0.1％、或小于或等于±0.05％。另外，有时在本文中以范围格式呈现量、比率和其它数值。应理解，此类范围格式是用于便利及简洁起见，且应灵活地理解，不仅包含明确地指定为范围限制的数值，而且包含涵盖于所述范围内的所有个别数值或子范围，如同明确地指定每一数值及子范围一般。
在具体实施方式及权利要求书中，由术语“中的至少一种”连接的项目的列表可意味着所列项目的任何组合。例如，如果列出项目A及B，那么短语“A及B中的至少一种”意味着仅A；仅B；或A及B。在另一实例中，如果列出项目A、B及C，那么短语“A、B及C中的至少一种”意味着仅A；或仅B；仅C；A及B(排除C)；A及C(排除B)；B及C(排除A)；或A、B及C的全部。项目A可包含单个元件或多个 元件。项目B可包含单个元件或多个元件。项目C可包含单个元件或多个元件。
正极
正极包括正极集流体和设置在所述正极集流体上的正极材料，所述正极材料包括正极活性材料。
随着电化学装置(例如，锂离子电池)的广泛应用，人们对其性能的要求越来越高，尤其是快速充电性能。采用高电压充电是提高充电速度、缩短充电时间的方式之一。然而，在高电压工作条件下，传统电化学装置面临诸多挑战，例如，循环性能和存储性能下降、阻抗增大、使用寿命缩短、能量密度降低等。造成这些问题的原因之一在于在高电压条件下，正极活性材料的表面易于发生氧化还原分解。通常可通过表面包覆的方式改性正极活性材料表面性能，从而改善电化学装置的高电压快充性能。然而，表面包覆方法的难点在于选择何种材料作为包覆层、采用何种方法实现包覆以及如何确定包覆量。
为了解决上述问题，本申请采用掺杂方式以在正极活性材料表面提供特定含量的铝元素，从而改善电化学装置在高电压工作条件下的阻抗、循环性能和高温存储性能。具体来说，本申请提供了一种正极活性材料，所述正极活性材料的表面区域的至少一部分包含铝元素，基于所述正极活性材料的重量，所述表面区域中的所述铝元素的含量为A wt％，A为0.01至1。在一些实施例中，A为0.2至0.8。在一些实施例中，A为0.3至0.6。在一些实施例中，A为0.01、0.02、0.04、0.06、0.09、0.1、0.2、0.3、0.4、0.5、0.6、0.7、0.8、0.9、1或在以上任何数值所组成的范围内。
如本文所述，正极活性材料的“表面区域”指的是正极活性材料颗粒的最外面朝向中心方向小于或等于200nm的范围的区域。
当正极活性材料的表面区域包含上述含量的铝元素时，可显著降低电化学装置在高电压工作条件下的阻抗并显著提高其循环性能和高温存储性能。
在一些实施例中，所述正极活性材料的内部区域包含铝元素，基于所述正极活性材料的重量，所述内部区域中的所述铝元素的含量为A 1wt％，A 1满足以下条件中的至少一者：(a)A 1为0.05至2；(b)A 1＞A；(c)1＜A 1/A＜10。如本文所述，正极活性材料的“内部区域”指的是正极活性材料颗粒的除表面区域以外的区域。
在一些实施例中，A 1为0.05至1.5。在一些实施例中，A 1为0.07至1.2。在一些实施例中，A 1为0.1至1.0。在一些实施例中，A 1为0.2至0.9。在一些实施例中，A 1为0.05、0.06、0.09、0.1、0.2、0.3、0.4、0.5、0.6、0.7、0.8、0.9、1.0、1.1、1.2、1.5、 1.8、2或在以上任何数值所组成的范围内。
在一些实施例中，A 1＞A。
在一些实施例中，2≤A 1/A≤8。在一些实施例中，2.5≤A 1/A≤5。在一些实施例中，A 1/A为1.5、2、2.5、3、3.5、4、4.5、5、5.5、6、6.5、7、7.5、8、8.5、9、9.5或在以上任何数值所组成的范围内。
在一些实施例中，所述正极活性材料的表面区域的至少一部分进一步包含镧元素，基于所述正极活性材料的重量，所述表面的至少一部分区域中的所述镧元素的含量为B wt％，B满足以下条件中的至少一者：(d)B为0.01至0.8；(e)0.01≤B/A≤0.8。
在一些实施例中，B为0.01至0.6。在一些实施例中，B为0.02至0.5。在一些实施例中，B为0.05至0.3。在一些实施例中，B为0.05至0.2。在一些实施例中，B为0.01、0.03、0.05、0.07、0.1、0.2、0.3、0.4、0.5、0.6、0.7、0.8或在以上任何数值所组成的范围内。
在一些实施例中，0.02≤B/A≤0.6。在一些实施例中，0.03≤B/A≤0.5。在一些实施例中，0.05≤B/A≤0.3。在一些实施例中，0.05≤B/A≤0.2。在一些实施例中，B/A为0.01、0.03、0.05、0.07、0.1、0.2、0.3、0.4、0.5、0.6、0.7、0.8或在以上任何数值所组成的范围内。
当正极活性材料的表面区域包括满足上述条件的镧元素时，可进一步改善电化学装置在高电压工作条件下的阻抗、循环性能和高温存储性能。
在一些实施例中，所述正极活性材料的表面区域的至少一部分进一步包含锂、钴、镍、锰、镁、钛、锆、氟或钇中的至少一种元素。在一些实施例中，所述正极活性材料的表面区域的至少一部分进一步包含锂、钴以及镍、锰、镁、钛、锆、氟或钇中的至少一种元素。在一些实施例中，所述正极活性材料的表面区域的至少一部分进一步包含镁、钛、锆、氟或钇中的至少一种元素。当正极活性材料的表面区域包含上述元素时，可进一步改善电化学装置在高电压工作条件下的阻抗、循环性能和高温存储性能。
在一些实施例中，正极活性材料的内部区域包含镧元素，基于所述正极活性材料的重量，所述内部区域中的所述镧元素的含量为D wt％，D满足以下条件中的至少一者：(f)D为0.01至0.4；(g)B＞D；(h)1＜B/D＜10。
在一些实施例中，D为0.01至0.3。在一些实施例中，D为0.03至0.2。在一些实施例中，D为0.01、0.03、0.05、0.07、0.1、0.15、0.2、0.25、0.3、0.35、0.4或在以上任何数值所组成的范围内。
在一些实施例中，1＜B/D≤5。在一些实施例中，B/D为1.2、1.5、2、2.5、3、3.5、4、4.5、5、5.5、6、6.5、7、7.5、8、8.5、9、9.5或在以上任何数值所组成的范围内。
当正极活性材料的内部区域包含满足上述条件的镧元素时，可进一步改善电化学装置在高电压工作条件下的阻抗、循环性能和高温存储性能。
在一些实施例中，所述正极活性材料包含第一颗粒和第二颗粒，所述第一颗粒的平均粒径大于所述第二颗粒的平均粒径。在一些实施例中，所述第一颗粒包含一次颗粒。在一些实施例中，所述第二颗粒为二次颗粒。在一些实施例中，所述第二颗粒为多晶颗粒。组合使用较大尺寸的一次颗粒和较小尺寸的二次颗粒有助于提高正极活性材料层的压实密度，同时进一步改善电化学装置在高电压工作条件下的阻抗、循环性能和高温存储性能。
在一些实施例中，所述正极活性材料满足以下条件中的至少一者：(i)所述第一颗粒的Dv50为10μm至15μm；(j)所述第一颗粒的Dv99为20μm至30μm；(k)所述第一颗粒的Dv50与Dv99满足：1.5≤Dv99/Dv50＜3；(l)所述第二颗粒的Dv50'为2μm至6μm；或(m)所述第一颗粒的Dv50与所述第二颗粒的Dv50'满足：2≤Dv50/Dv50'＜8。
在一些实施例中，所述第一颗粒的Dv50为12μm至14μm。在一些实施例中，所述第一颗粒的Dv50为10μm、11μm、12μm、13μm、14μm、15μm或在以上任何数值所组成的范围内。
在一些实施例中，所述第一颗粒的Dv99为22μm至28μm。在一些实施例中，所述第一颗粒的Dv99为24μm至26μm。在一些实施例中，所述第一颗粒的Dv90为20μm、21μm、22μm、23μm、24μm、25μm、26μm、27μm、28μm、29μm、30μm或在以上任何数值所组成的范围内。
在一些实施例中，所述第一颗粒的Dv50与Dv99满足2.0≤Dv99/Dv50≤2.6。在一些实施例中，所述第一颗粒的Dv99/Dv50为1.5、1.6、1.7、1.8、1.9、2.0、2.2、2.3、2.4、2.5、2.6、2.7、2.8、2.9或在以上任何数值所组成的范围内。
在一些实施例中，所述第二颗粒的Dv50'为3μm至5μm。在一些实施例中，所述第二颗粒的Dv50'为2μm、3μm、4μm、5μm、6μm或在以上任何数值所组成的范围内。
在一些实施例中，所述第一颗粒的Dv50与所述第二颗粒的Dv50'满足：2≤Dv50/Dv50'≤7。在一些实施例中，所述第一颗粒的Dv50与所述第二颗粒的Dv50'的比 值Dv50/Dv50'为2、3、4、5、6、7或在以上任何数值所组成的范围内。
当正极活性材料中的第一颗粒和第二颗粒的粒径满足上述条件时，可进一步改善电化学装置在高电压工作条件下的阻抗、循环性能和高温存储性能。
在一些实施例中，所述第二颗粒包含二次颗粒，形成所述二次颗粒的一次颗粒的平均粒径为0.1μm至3μm。在一些实施例中，形成所述二次颗粒的一次颗粒的平均粒径为0.5μm至2μm。在一些实施例中，形成所述二次颗粒的一次颗粒的平均粒径为1μm至1.5μm。在一些实施例中，形成所述二次颗粒的一次颗粒的平均粒径为0.1μm、0.5μm、1μm、1.5μm、2μm、2.5μm、3μm或在以上任何数值所组成的范围内。当第二颗粒中的二次颗粒由具有上述平均粒径的一次颗粒形成时，可进一步改善电化学装置在高电压工作条件下的阻抗、循环性能和高温存储性能。
在一些实施例中，所述第二颗粒中一次颗粒的粒径可以通过控制原料的粒径或通过控二次颗粒制备过程中的烧结温度和/或烧结时间来控制。
在一些实施例中，所述第一颗粒中镧元素的含量小于所述第二颗粒中镧元素的含量。
在一些实施例中，基于所述正极活性材料的重量，所述第一颗粒中镧元素的含量为E wt％，所述第二颗粒中镧元素的含量为F wt％，E为0.01至0.6，F为0.01至0.9。在一些实施例中，E为0.01至0.5。在一些实施例中，E为0.05至0.4。在一些实施例中，E为0.1至0.2。在一些实施例中，E为0.01、0.05、0.1、0.2、0.3、0.4、0.5、0.6或在以上任何数值所组成的范围内。在一些实施例中，F为0.01至0.4。在一些实施例中，F为0.05至0.3。在一些实施例中，F为0.1至0.2。在一些实施例中，F为0.01、0.05、0.1、0.2、0.3、0.4、0.5或在以上任何数值所组成的范围内。当第一颗粒和第二颗粒中的镧元素含量在上述范围内时，可进一步改善电化学装置在高电压工作条件下的阻抗、循环性能和高温存储性能。
在一些实施例中，0.5≤E/F＜1。在一些实施例中，0.6≤E/F≤0.9。在一些实施例中，E/F为0.5、0.6、0.7、0.8、0.9或在以上任何数值所组成的范围内。当第一颗粒和第二颗粒中的镧元素含量满足上述条件时，可进一步改善电化学装置在高电压工作条件下的阻抗、循环性能和高温存储性能。
在一些实施例中，采用XRD测试，所述正极活性材料在23.0°-24.0°范围内的最强峰与32.5°-33.5°范围内的最强峰的峰强比为0.6至1.5。正极活性材料在23.0°-24.0°和32.5°-33.5°范围内出现新的特征峰表明正极活性材料中存在新物相。
在一些实施例中，所述正极活性材料包括钴锂氧化物、锰锂氧化物、或镍钴锰锂氧化物中的至少一种。
在一些实施例中，所述钴锂氧化物包含Li aCo bM cM2 dO 2，其中，0.90≤a≤1.2，0.9≤b＜1，0＜c≤0.1，0≤d＜0.1，M包含铝以及镧、镍、锰、镁、钛、锆、氟、钨、硼或钇中的至少一种，M2包含钠、铁、硅、锌或磷中的至少一种。
在一些实施例中，所述锰锂氧化物包含Li aMn bM cM2 dO 2，其中0.90≤a≤1.8，0.9≤b＜1，0＜c≤0.1，0≤d＜0.1，M包含铝以及镧、镍、锰、镁、钛、锆、氟、钨、硼或钇中的至少一种，M2包含钠、铁、硅、锌或磷中的至少一种。
在一些实施例中，所述镍钴锰锂氧化物包含Li aNi bCo cMn dM eO 2，其中0.90≤a≤1.2，0＜b≤0.95，0＜c≤0.4，0<d≤0.4，0＜e≤0.1，M包含铝以及镧、镁、钛、锆、氟、钨、硼或钇中的至少一种。
在一些实施例中，所述正极活性材料中锂元素的摩尔量占比会在电化学装置化成过程中损耗，导致锂元素的摩尔占比下降。
在一些实施例中，所述正极材料还包含粘合剂，并且可选地还包括正极导电材料。
粘合剂可提高正极活性材料颗粒彼此间的结合，并且还可提高正极活性材料与正极集流体的结合。粘合剂的非限制性示例包括聚乙烯醇、羟丙基纤维素、二乙酰基纤维素、聚氯乙烯、羧化的聚氯乙烯、聚氟乙烯、聚乙烯吡咯烷酮、聚氨酯、聚四氟乙烯、聚偏1,1-二氟乙烯、聚乙烯、聚丙烯、丁苯橡胶、丙烯酸(酯)化的丁苯橡胶、环氧树脂、尼龙等。
在一些实施例中，所述正极材料还包括正极导电材料，从而赋予电极导电性。所述正极导电材料可以包括任何导电材料，只要它不引起化学变化。正极导电材料的非限制性示例包括基于碳的材料(例如，天然石墨、人造石墨、碳黑、乙炔黑、科琴黑、碳纤维等)、基于金属的材料(例如，金属粉、金属纤维等，包括例如铜、镍、铝、银等)、导电聚合物(例如，聚亚苯基衍生物)和它们的混合物。
在一些实施例中，正极集流体可以是铝(Al)，但不限于此。
本申请还提供了一种制备本申请所述的正极活性材料的方法，其包括：步骤S1：将包括正极活性材料前体材料的混合物在600℃至1500℃的温度下烧结，得到初级正极活性材料X；步骤S2：将包括所述初级正极活性材料X与含有铝元素的化合物的原料在600℃至1000℃的温度下烧结，得到正极活性材料。当在初级正极活性材料X中加入含铝元素的化合物并烧结时，在特定高温下，铝元素会发生热扩散，导致部分铝元素 形成于正极活性材料的表面区域。
本申请还提供了一种制备本申请所述的正极活性材料的方法，其包括：
步骤S1-1：将包括第一正极活性材料前体材料的第一混合物在温度T1下烧结，得到第一初级正极活性材料X1；
步骤S2-1：将包括所述第一初级正极活性材料X1与含有铝元素的第一化合物的第一原料在温度T1'下烧结，得到第一颗粒；
步骤S1-2：将包括第二正极活性材料前体材料的第二混合物在温度T2下烧结，得到第二初级正极活性材料X2；
步骤S2-2：将包括所述第二初级正极活性材料X2与含有铝元素的第二化合物的第二原料在温度T2'下烧结，得到第二颗粒；
步骤S3：混合所述第一颗粒和所述第二颗粒，得到所述正极活性材料。
在一些实施例中，在步骤S1、S2、S1-1、S2-1、S1-2或S2-2中的至少一者中，烧结时间为4小时至12小时。
在一些实施例中，在步骤S1-1中，所述温度T1为800℃至1150℃。
在一些实施例中，在步骤S1-1中，烧结时间为8至24小时。
在一些实施例中，在步骤S2-1中，所述温度T1'为700℃至1000℃。
在一些实施例中，在步骤S2-1中，烧结时间为4至12小时。
在一些实施例中，在步骤S1-2中，所述温度T2为800℃至1050℃。
在一些实施例中，在步骤S1-2中，烧结时间为8至24小时。
在一些实施例中，在步骤S2-2中，所述温度T2'为600℃至950℃。
在一些实施例中，在步骤S2-2中，烧结时间为4至12小时。
在一些实施例中，所述混合物、所述第一混合物或所述第二混合物的至少一者任选地包含具有铝元素、镁元素、钛元素、锆元素或钇元素的化合物。
在一些实施例中，所述混合物、所述第一混合物或所述第二混合物的至少一者进一步包括含有铝元素的化合物。
在一些实施例中，所述混合物、所述第一混合物或所述第二混合物的至少一者包含铝元素，以及任选地包含具有镁元素、钛元素、锆元素或钇元素的化合物。
在一些实施例中，所述原料、所述第一原料或所述第二原料中的至少一者任选地包括镍、锰、镁、钛、锆、氟或钇中的至少一种元素。
在一些实施例中，所述原料、所述第一原料或所述第二原料中的至少一者任选地包 括具有镍元素、锰元素、镁元素、钛元素、锆元素、氟元素或钇元素的化合物。
在一些实施例中，所述混合物、所述第一混合物或所述第二混合物的至少一者进一步包括含有镧元素的化合物。镧元素在特定高温下倾向于向颗粒表面热扩散，使得正极活性材料的表面区域的镧元素含量大于内部区域的镧元素含量。
在一些实施例中，基于所述混合物、所述第一混合物或所述第二混合物的重量，所述镧元素的含量为0.01％至5％。在一些实施例中，所述镧元素的含量为0.05％至3％。在一些实施例中，所述镧元素的含量为0.1％至2％。在一些实施例中，所述镧元素的含量为0.5％至1％。
在一些实施例中，所述混合物、所述第一混合物或所述第二混合物的至少一者进一步包括含有M元素的化合物，所述M元素包括以下元素中的至少一种：锂、钴、镍、锰、镁、钛、锆、氟、钇、铌、硼、钼、钒和铈。
在一些实施例中，所述混合物、所述第一混合物或所述第二混合物的至少一者进一步包括含有M元素的化合物，所述M元素包括锂、钴以及以下元素中的至少一种：锂、钴、镍、锰、镁、钛、锆、氟、钇、铌、硼、钼、钒和铈。
在一些实施例中，所述混合物、所述第一混合物或所述第二混合物的至少一者进一步包括含有M元素的化合物，所述M元素包括以下元素中的至少一种：镁、钛、锆、氟、钇、铌、硼、钼、钒和铈。
在一些实施例中，所述原料、所述第一原料或所述第二原料的至少一者进一步包括含有M元素的化合物，所述M元素包括以下元素中的至少一种：锂、钴、镍、锰、镁、钛、锆、氟、钇、铌、硼、钼、钒和铈。
在一些实施例中，所述原料、所述第一原料或所述第二原料的至少一者进一步包括含有M元素的化合物，所述M元素包括锂、钴以及以下元素中的至少一种：锂、钴、镍、锰、镁、钛、锆、氟、钇、铌、硼、钼、钒和铈。
在一些实施例中，所述含有M元素的化合物为M元素的氧化物、M元素的氢氧化物、M元素的碳酸盐、M元素的磷酸盐或M元素的氟化物中的至少一种。
在一些实施例中，所述正极活性材料前体材料、所述第一正极活性材料前体材料和所述第二正极活性材料前体材料中的至少一种包括含有钴元素的化合物和锂盐。
在一些实施例中，所述含有钴元素的化合物包括氧化钴或氢氧化钴中的至少一种。
在一些实施例中，所述锂盐包括碳酸锂、氧化锂或氢氧化锂中的至少一种。
在一些实施例中，所述含有钴元素的化合物与所述锂盐的摩尔比为0.90:1至1.1:1。
在一些实施例中，所述含有钴元素的化合物与所述锂盐的摩尔比为0.90:1至1.08:1。
在一些实施例中，在所述步骤S3中，所述第一颗粒和所述第二颗粒按照1:9至9:1的质量比混合，得到所述正极活性材料。在一些实施例中，在所述步骤S3中，所述第一颗粒和所述第二颗粒按照2:8至8:2的质量比混合。在一些实施例中，在所述步骤S3中，所述第一颗粒和所述第二颗粒按照3:7至7:3的质量比混合。在一些实施例中，在所述步骤S3中，所述第一颗粒和所述第二颗粒按照4:6至6:4的质量比混合。在一些实施例中，在所述步骤S3中，所述第一颗粒和所述第二颗粒按照5:5的质量比混合。
负极
负极包括集流体和设置在集流体上的负极活性材料层。负极活性材料的具体种类均不受到具体的限制，可根据需求进行选择。
在一些实施例中，所述负极活性材料选自天然石墨、人造石墨、中间相微碳球(简称为MCMB)、硬碳、软碳、硅、硅-碳复合物、Li-Sn合金、Li-Sn-O合金、Sn、SnO、SnO 2、尖晶石结构的锂化TiO 2-Li 4Ti 5O 12、Li-Al合金中的一种或几种。
碳材料的非限制性示例包括结晶碳、非晶碳和它们的混合物。结晶碳可以是无定形的或片形的、小片形的、球形的或纤维状的天然石墨或人造石墨。非晶碳可以是软碳、硬碳、中间相沥青碳化物、煅烧焦等。
在一些实施例中，负极活性材料层可以包含粘合剂，并且可选地还包括导电材料。
粘合剂提高负极活性材料颗粒彼此间的结合和负极活性材料与集流体的结合。粘合剂的非限制性示例包括聚乙烯醇、羧甲基纤维素、羟丙基纤维素、二乙酰基纤维素、聚氯乙烯、羧化的聚氯乙烯、聚氟乙烯、含亚乙基氧的聚合物、聚乙烯吡咯烷酮、聚氨酯、聚四氟乙烯、聚偏1,1-二氟乙烯、聚乙烯、聚丙烯、丁苯橡胶、丙烯酸(酯)化的丁苯橡胶、环氧树脂、尼龙等。
负极活性材料层包括导电材料，从而赋予电极导电性。所述导电材料可以包括任何导电材料，只要它不引起化学变化。导电材料的非限制性示例包括基于碳的材料(例如，天然石墨、人造石墨、碳黑、乙炔黑、科琴黑、碳纤维等)、基于金属的材料(例如，金属粉、金属纤维等，例如铜、镍、铝、银等)、导电聚合物(例如，聚亚苯基衍生物)和它们的混合物。
用于本申请所述的负极的集流体可以选自铜箔、镍箔、不锈钢箔、钛箔、泡沫镍、泡沫铜、覆有导电金属的聚合物基底和它们的组合。
电解液
可用于本申请实施例的电解液中的锂盐包括、但不限于：无机锂盐，例如LiClO 4、LiAsF 6、LiPF 6、LiBF 4、LiSbF 6、LiSO 3F、LiN(FSO 2) 2等；含氟有机锂盐，例如LiCF 3SO 3、LiN(FSO 2)(CF 3SO 2)、LiN(CF 3SO 2) 2、LiN(C 2F 5SO 2) 2、环状1,3-六氟丙烷二磺酰亚胺锂、环状1,2-四氟乙烷二磺酰亚胺锂、LiN(CF 3SO 2)(C 4F 9SO 2)、LiC(CF 3SO 2) 3、LiPF 4(CF 3) 2、LiPF 4(C 2F 5) 2、LiPF 4(CF 3SO 2) 2、LiPF 4(C 2F 5SO 2) 2、LiBF 2(CF 3) 2、LiBF2(C2F5)2、LiBF 2(CF 3SO 2) 2、LiBF 2(C 2F 5SO 2) 2；含二羧酸配合物锂盐，例如双(草酸根合)硼酸锂、二氟草酸根合硼酸锂、三(草酸根合)磷酸锂、二氟双(草酸根合)磷酸锂、四氟(草酸根合)磷酸锂等。另外，上述锂盐可以单独使用一种，也可以同时使用两种或两种以上。在一些实施例中，锂盐包括LiPF 6和LiBF 4的组合。在一些实施例中，锂盐包括LiPF 6或LiBF 4等无机锂盐与LiCF 3SO 3、LiN(CF 3SO 2) 2、LiN(C 2F 5SO 2) 2等含氟有机锂盐的组合。在一些实施例中，锂盐的浓度在0.8mol/L至3mol/L的范围内，0.8mol/L至2.5mol/L的范围内、0.8mol/L至2mol/L的范围或1mol/L至2mol/L的范围内。在一些实施例中，锂盐的浓度为约1mol/L、约1.15mol/L、约1.2mol/L、约1.5mol/L、约2mol/L或约2.5mol/L。
可用于本申请实施例的电解液中的溶剂包括、但不限于：环状碳酸酯、链状碳酸酯、环状羧酸酯、链状羧酸酯、环状醚、链状醚、含磷有机溶剂、含硫有机溶剂和芳香族含氟溶剂。
在一些实施例中，环状碳酸酯包括，但不限于：碳酸亚乙酯(ethylene carbonate，EC)、碳酸亚丙酯(propylene carbonate，PC)和碳酸亚丁酯。在一些实施例中，环状碳酸酯具有3-6个碳原子。
在一些实施例中，链状碳酸酯包括，但不限于：碳酸二甲酯、碳酸甲乙酯、碳酸二乙酯(diethyl carbonate，DEC)、碳酸甲基正丙基酯、碳酸乙基正丙基酯、碳酸二正丙酯等链状碳酸酯，作为被氟取代的链状碳酸酯，例如双(氟甲基)碳酸酯、双(二氟甲基)碳酸酯、双(三氟甲基)碳酸酯、双(2-氟乙基)碳酸酯、双(2,2-二氟乙基)碳酸酯、双(2,2,2-三氟乙基)碳酸酯、2-氟乙基甲基碳酸酯、2,2-二氟乙基甲基碳酸酯和2,2,2-三氟乙基甲基碳酸酯。
在一些实施例中，环状羧酸酯包括，但不限于：γ-丁内酯和γ-戊内酯。在一些实施例中，环状羧酸酯的部分氢原子可被氟取代。
在一些实施例中，链状羧酸酯包括，但不限于：乙酸甲酯、乙酸乙酯、乙酸丙酯、乙酸异丙酯、乙酸丁酯、乙酸仲丁酯、乙酸异丁酯、乙酸叔丁酯、丙酸甲酯、丙酸乙 酯、丙酸丙酯、丙酸异丙酯、丁酸甲酯、丁酸乙酯、丁酸丙酯、异丁酸甲酯、异丁酸乙酯、戊酸甲酯、戊酸乙酯、特戊酸甲酯和特戊酸乙酯。在一些实施例中，链状羧酸酯的部分氢原子可被氟取代。在一些实施例中，氟取代的链状羧酸酯包括，但不限于：三氟乙酸甲酯、三氟乙酸乙酯、三氟乙酸丙酯、三氟乙酸丁酯和三氟乙酸2,2,2-三氟乙酯。
在一些实施例中，环状醚包括，但不限于：四氢呋喃、2-甲基四氢呋喃、1,3-二氧戊环、2-甲基1,3-二氧戊环、4-甲基1,3-二氧戊环、1,3-二氧六环、1,4-二氧六环和二甲氧基丙烷。
在一些实施例中，链状醚包括，但不限于：二甲氧基甲烷、1,1-二甲氧基乙烷、1,2-二甲氧基乙烷、二乙氧基甲烷、1,1-二乙氧基乙烷、1,2-二乙氧基乙烷、乙氧基甲氧基甲烷、1,1-乙氧基甲氧基乙烷和1,2-乙氧基甲氧基乙烷。
在一些实施例中，含磷有机溶剂包括，但不限于：磷酸三甲酯、磷酸三乙酯、磷酸二甲基乙酯、磷酸甲基二乙酯、磷酸亚乙基甲酯、磷酸亚乙基乙酯、磷酸三苯酯、亚磷酸三甲酯、亚磷酸三乙酯、亚磷酸三苯酯、磷酸三(2,2,2-三氟乙基)酯和磷酸三(2,2,3,3,3-五氟丙基)酯。
在一些实施例中，含硫有机溶剂包括，但不限于：环丁砜、2-甲基环丁砜、3-甲基环丁砜、二甲基砜、二乙基砜、乙基甲基砜、甲基丙基砜、二甲基亚砜、甲磺酸甲酯、甲磺酸乙酯、乙磺酸甲酯、乙磺酸乙酯、硫酸二甲酯、硫酸二乙酯和硫酸二丁酯。在一些实施例中，含硫有机溶剂的部分氢原子可被氟取代。
在一些实施例中，芳香族含氟溶剂包括，但不限于：氟苯、二氟苯、三氟苯、四氟苯、五氟苯、六氟苯和三氟甲基苯。
在一些实施例中，本申请的电解液中使用的溶剂包括如上所述的一种或多种。在一些实施例中，本申请的电解液中使用的溶剂包括环状碳酸酯、链状碳酸酯、环状羧酸酯、链状羧酸酯及其组合。在一些实施例中，本申请的电解液中使用的溶剂包含选自由下列物质组成的群组的有机溶剂：碳酸亚乙酯、碳酸亚丙酯、碳酸二乙酯、丙酸乙酯、丙酸丙酯、乙酸正丙酯、乙酸乙酯及其组合。在一些实施例中，本申请的电解液中使用的溶剂包含：碳酸亚乙酯、碳酸亚丙酯、碳酸二乙酯、丙酸乙酯、丙酸丙酯、γ-丁内酯或其组合。
可用于本申请实施例的电解液中的添加剂包括、但不限于：具有2-3个氰基的化合物、含碳碳双键的环状碳酸酯、含硫氧双键的化合物、二氟磷酸锂。
在一些实施例中具有2-3个氰基的化合物，可以包括选自丁二腈(SN)、己二腈(ADN)、乙二醇双(丙腈)醚(EDN)、1,3,5-戊三甲腈、1,2,3-丙三甲腈、1,3,6-己烷三甲腈(HTCN)、1,2,6-己烷三甲腈、1,2,3-三(2-氰基乙氧基)丙烷(TCEP)或1,2,4-三(2-氰基乙氧基)丁烷中的至少一种；基于所述电解液的总重量，所述具有2-3个氰基的化合物的含量为0.1％-10％。
在一些实施例中具有碳-碳双键的环状碳酸酯具体包括，但不限于：碳酸亚乙烯酯、碳酸甲基亚乙烯酯、碳酸乙基亚乙烯酯、乙烯基碳酸乙烯亚乙酯或碳酸-1,2-二甲基亚乙烯酯中的至少一种。
在一些实施例中含硫氧双键的化合物包括，但不限于：硫酸乙烯酯、1,2-丙二醇硫酸酯、1,3-丙磺酸内酯、1-氟-1,3-丙磺酸内酯、2-氟-1,3-丙磺酸内酯或3-氟-1,3-丙磺酸内酯中的至少一种。
隔离膜
正极与负极之间可设有隔离膜以防止短路。可用于本申请的实施例中使用的隔离膜的材料和形状没有特别限制，其可为任何现有技术中公开的技术。在一些实施例中，隔离膜包括由对本申请的电解液稳定的材料形成的聚合物或无机物等。
例如，隔离膜可包括基材层和表面处理层。基材层为具有多孔结构的无纺布、膜或复合膜，基材层的材料选自聚乙烯、聚丙烯、聚对苯二甲酸乙二醇酯和聚酰亚胺中的至少一种。具体的，可选用聚丙烯多孔膜、聚乙烯多孔膜、聚丙烯无纺布、聚乙烯无纺布或聚丙烯-聚乙烯-聚丙烯多孔复合膜。
基材层的至少一个表面上设置有表面处理层，表面处理层可以是聚合物层或无机物层，也可以是混合聚合物与无机物所形成的层。
无机物层包括无机颗粒和粘结剂，无机颗粒选自氧化铝、氧化硅、氧化镁、氧化钛、二氧化铪、氧化锡、二氧化铈、氧化镍、氧化锌、氧化钙、氧化锆、氧化钇、碳化硅、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙和硫酸钡中的一种或几种的组合。粘结剂选自聚偏氟乙烯、偏氟乙烯-六氟丙烯的共聚物、聚酰胺、聚丙烯腈、聚丙烯酸酯、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯醚、聚甲基丙烯酸甲酯、聚四氟乙烯和聚六氟丙烯中的一种或几种的组合。
聚合物层中包含聚合物，聚合物的材料选自聚酰胺、聚丙烯腈、丙烯酸酯聚合物、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯醚、聚偏氟乙烯、聚(偏氟乙烯-六氟丙烯)中的至少一种。
电化学装置
本申请的电化学装置包括发生电化学反应的任何装置，它的具体实例包括所有种类的一次电池或二次电池。锂二次电池可包括锂金属二次电池、锂离子二次电池、锂聚合物二次电池或锂离子聚合物二次电池。
电子装置
本申请另提供了一种电子装置，其包括根据本申请的电化学装置。本申请的电化学装置的用途没有特别限定，其可用于现有技术中已知的任何电子装置。在一些实施例中，本申请的电化学装置可用于，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、家庭用大型蓄电池和锂离子电容器等。
下面以锂离子电池为例并且结合具体的实施例说明锂离子电池的制备，本领域的技术人员将理解，本申请中描述的制备方法仅是实例，其他任何合适的制备方法均在本申请的范围内。
实施例
以下说明根据本申请的锂离子电池的实施例和对比例进行性能评估。
一、锂离子电池的制备
1、正极的制备
对比例1的正极材料制备：
分别称取四氧化三钴1000g和碳酸锂461g，其中四氧化三钴的Dv50为12μm，未添加氧化镧、氧化铝添加剂，混合后在空气氛围内1050℃温度下烧结16小时，得到初级正极活性材料。将得到的初级正极活性材料继续在800℃烧结12小时，获得正极活性材料。
对比例2的正极材料制备：
分别称取四氧化三钴1000g、碳酸锂461g和氧化铝0.23g，其中四氧化三钴的Dv50为12μm，混合后在空气氛围内1000℃温度下烧结15小时，得到初级正极活性材料。将得到的初级正极活性材料和0.12g氧化铝混合后继续在850℃烧结10小时，获得正极活性材料。
对比例3和4的正极材料制备：
采用与对比例2基本相同的制备方法，不同之处在于通过铝元素的添加量调整正极活性材料的表面区域与内部区域的铝元素含量，得到正极活性材料。
对比例5正极材料制备：
分别称取四氧化三钴1000g和碳酸锂461g，其中四氧化三钴的Dv50'为4μm，其一次颗粒平均粒径为0.3μm，混合后在空气氛围内800℃温度下烧结12小时，得到初级正极活性材料。将得到的初级正极活性材料继续在700℃到烧结12小时，获得正极活性材料。
对比例6的正极材料制备：
分别称取四氧化三钴1000g和碳酸锂461g，其中四氧化三钴的Dv50为12μm，混合后在空气氛围内1050℃温度下烧结16小时，得到第一初级正极活性材料。将得到的第一初级正极活性材料在800℃烧结12小时，获得第一颗粒。
分别称取四氧化三钴250g和碳酸锂115g，其中四氧化三钴的Dv50'为3μm，其一次颗粒粒径为0.3μm，混合后在空气氛围内800℃温度下烧结12小时，得到第二初级正极活性材料。将得到的第二初级正极活性材料在700℃烧结12小时，获得第二颗粒。
将制得的第一颗粒和第二颗粒按照8:2的质量比进行混合，得到正极活性材料。
实施例1的正极材料制备：
分别称取四氧化三钴1000g和碳酸锂461g，其中四氧化三钴的Dv50为12μm，混合后在空气氛围内1020℃温度下烧结15小时，得到初级正极活性材料。将得到的初级正极活性材料与0.23g氧化铝混合，将混合料在800℃烧结12小时，获得正极活性材料。
实施例2和3的正极材料制备：
采用与实施例1基本相同的制备方法，不同之处在于通过铝元素的添加量调节正极活性材料的表面区域的铝元素含量。
实施例4的正极材料制备：
分别称取四氧化三钴1000g、碳酸锂461g和氧化铝4.6g，其中四氧化三钴的Dv50为12μm，混合后在空气氛围内1050℃温度下烧结16小时，得到初级正极活性材料。将得到的初级正极活性材料与0.23g氧化铝混合，将混合料在800℃烧结12小时，获得正极活性材料。
实施例5-21的正极材料制备：
采用与实施例4基本相同的制备方法，不同之处在于通过铝元素的添加量调节正极活性材料的表面区域与内部区域的铝元素含量。
实施例22的正极材料制备：
分别称取四氧化三钴1000g、碳酸锂461g和氧化铝23g，其中四氧化三钴的Dv50'为4.0μm，其一次颗粒平均粒径为0.3μm，混合后在空气氛围内800℃温度下烧结12小时，得到初级正极活性材料。将得到的初级正极活性材料与3.5g氧化铝混合，在700℃烧结12小时，获得正极活性材料。
实施例23的正极材料制备：
分别称取四氧化三钴1000g、碳酸锂461g和氧化铝17.3g，其中四氧化三钴的Dv50为12μm，混合后在空气氛围内1050℃温度下烧结16小时，得到未包覆的钴酸锂。将得到的未包覆的钴酸锂与3.5g氧化铝和0.7g氧化镧混合，未添加其他元素，将混合料在800℃烧结12小时，获得正极活性材料。
实施例24-33的正极材料制备：
采用与实施例23基本相同的方法，不同之处在于通过镧元素的添加量调节正极活性材料的表面区域的镧元素含量。
实施例34的正极材料制备：
分别称取四氧化三钴1000g、碳酸锂461g、氧化铝17.3g和氧化镧0.7g，其中四氧化三钴的Dv50为12μm，混合后在空气氛围内1050℃温度下烧结16小时，得到初级正极活性材料。将得到的初级正极活性材料与3.5g氧化铝和1.4g氧化镧混合，将混合料在800℃烧结12小时，获得正极活性材料。
实施例35-44的正极材料制备：
采用与实施例34基本相同的制备方法，不同之处在于通过铝元素或镧元素的添加量调节正极活性材料的内部区域的镧元素、表面区域的铝元素、表面区域镧元素的含量。
实施例45的正极材料制备：
分别称取四氧化三钴1000g、碳酸锂461g、氧化镧1.0g和氧化铝17.3g，其中四氧化三钴的平均粒径为12μm，混合后在空气氛围内1050℃温度下烧结16小时，得到初级正极活性材料。将得到的初级正极活性材料与1.4g氧化镧、3.5g氧化铝以及2.0g二氧化钛混合，将混合料在800℃烧结12小时，获得正极活性材料。
实施例46的正极材料制备：
分别称取四氧化三钴1000g、碳酸锂461g、氧化镧1.0g和氧化铝17.3g，其中四氧化三钴的Dv50为12μm，混合后在空气氛围内1050℃温度下烧结16小时，得到初级正极活性材料。将得到的初级正极活性材料与1.4g氧化镧、3.5g氧化铝以及1.8g氧化锆混合，将混合料在800℃烧结12小时，获得正极活性材料。
实施例47的正极材料制备：
分别称取四氧化三钴1000g、碳酸锂461g、氧化镧1.0g和氧化铝17.3g，其中四氧化三钴的Dv50为12μm，混合后在空气氛围内1050℃温度下烧结16小时，得到初级正极活性材料。将得到的初级正极活性材料与1.4g氧化镧、3.5g氧化铝、1.5g氧化钇以及2.0g二氧化钛混合，将混合料在800℃烧结12小时，获得正极活性材料。
实施例48的正极材料制备：
分别称取四氧化三钴1000g、碳酸锂461g、氧化镧1.0g和氧化铝17.3g，其中四氧化三钴X1的Dv50为12μm，混合后在空气氛围内1050℃温度下烧结16小时，得到第一初级正极活性材料。将得到的第一初级正极活性材料与1.4g氧化镧、3.5g氧化铝以及2.0g二氧化钛混合，将混合料在800℃烧结12小时，获得第一颗粒。
分别称取四氧化三钴250g、碳酸锂115g、氧化镧0.3g和氧化铝4.3g，其中四氧化三钴的Dv50'为3μm，其一次颗粒粒径为0.3μm，混合后在空气氛围内800℃温度下烧结12小时，得到第二初级正极活性材。将得到的第二初级正极活性材与0.4g氧化镧、0.9g氧化铝以及0.5g二氧化钛混合，将混合料在700℃烧结12小时，获得第二颗粒。
将制得的第一颗粒和第二颗粒按照8:2的质量比进行混合，得到正极活性材料。
实施例49-68的正极活性材料的制备：
采用与实施例48基本相同的制备方法，不同之处在于正极活性材料的第一颗粒Dv50、第一颗粒Dv99、第二颗粒Dv50'和/或第二颗粒中一次颗粒的粒径。
实施例69-86的正极活性材料的制备：
采用与实施例48基本相同的制备方法，不同之处在于通过镧元素的添加量调节正极活性材料的第一颗粒中的镧元素的含量和/或第一颗粒中的镧元素的含量。
将正极活性材料、乙炔黑和聚偏二氟乙烯(PVDF)按照重量比为94:3:3溶于N-甲基吡咯烷酮(NMP)中，充分搅拌混合均匀，得到正极浆料。将该正极浆料涂覆于正极集流体铝箔上，烘干，冷压，得到正极活性材料层，再经过裁片、焊接极耳，得到正极。
2、负极的制备
将人造石墨、羧甲基纤维素钠(CMC)、丁苯橡胶(SBR)按照重量比96:2:2在适量的去离子水溶剂中充分搅拌混合，使其形成均匀的负极浆料。将该负极浆料涂覆于负极集流体铜箔上并在85℃下烘干。然后进行切边、裁片、分条、烘干，得到负极活性材料层，再经过裁片、焊接极耳，得到负极。
3、电解液的制备
在干燥氩气环境下，在碳酸丙烯酯(PC)，碳酸乙烯酯(EC)，碳酸二乙酯(DEC)(重量比1:1:1)混合而成的溶剂中，加入LiPF 6混合均匀，之后基于电解液的总重量，加入4％的氟代碳酸乙烯酯、2％的1,3-丙烷磺内酯、3％的己二腈和1％的1,3,6-己烷三腈，其中LiPF 6的浓度为1.15mol/L，得到电解液。
4、隔离膜的制备
将厚度为10μm的PE多孔聚合物薄膜作为隔离膜。
5、锂离子电池的制备
将正极、隔离膜和负极按顺序叠好，卷绕，，置于外包装中，注入电解液，封装。经过化成、脱气、切边等工艺流程得到锂离子电池。
二、测试方法
1、元素含量的测试方法
在25℃下将1g待测样品粉末加入到100mL 3％盐酸溶液中，在25℃下恒温消解4小时，然后将溶液过滤后分别取滤液和过滤残渣。
通过以下方法测试样品的表面区域的元素含量：将滤液定容到200mL，利用电感耦合等离子体发射光谱仪(ICP-OES)测试滤液中铝元素和镧元素的含量。
通过以下方法测试样品的内部区域的元素含量：将过滤残渣加入到10mL王水中完全消解，将消解后的溶液定容到50mL，利用ICP-OES测试消解液中镧元素的含量。
2、第一颗粒和第二颗粒的粒径的测试方法
将锂离子电池放电至电压为3.0V，将正极活性材料层从正极上取下，置于马弗炉中，在350℃、空气氛围下烧4小时，冷却后取出样品。用800目的筛子将样品进行筛分，得到第一颗粒和第二颗粒。
取0.5g待测样品粉末加入100mL烧杯中，加入一定量纯水，用玻璃棒搅拌，使得样品均匀分散。将样品加入激光粒度测试仪(LPS)的循环池中进行测试，并记录颗粒粒径(Dv50、Dv50'或Dv99)的测试结果。
3、二次颗粒中一次颗粒的平均粒径的测试方法
取0.5g待测样品粉末，放置到扫描电镜(SEM)观测剖面电镜，将倍率放大至10000倍，在显示范围内测量二次颗粒剖面中所有一次颗粒的粒度，并计算得到平均粒径。
4、XRD测试方法
采用X射线粉末衍射仪对待测样品粉末进行测试，参考JB/T 4220-2011测定方法进行测试，测试后获得样品的XRD谱图。
5、EIS阻抗测试方法
在25℃下，将锂离子电池以0.5C倍率恒流充电到3.85V，电压达到3.85V后进行恒压充电至电流低于0.025C，静置5分钟。然后采用EIS阻抗测试仪进行交流阻抗(EIS)测试。EIS测试的频率范围设定为0.1-10kHz，振幅设定为5mV。通过EIS测试得到锂离子电池的Rct阻抗值。
6、高温存储膨胀率的测试方法
在25℃下，将锂离子电池以0.5C倍率恒定电流充电至电压为4.50V，然后在4.50V恒定电压下充电至电流低于0.05C，使其处于4.50V满充状态。测试存储前的满充电池厚度，记为D0。然后将满充状态的锂离子电池置于85℃烘箱中存储24小时，取出锂离子电池后立即测试其存储后的厚度，记为D1。
根据下述公式计算锂离子电池的高温存储膨胀率：
高温存储膨胀率＝(D1-D0)/D0×100％。
7、循环容量保持率的测试方法
在25℃下，进行首次充放电，将锂离子电池在0.5C充电倍率下恒流充电到4.50V，然后恒压充电到0.025C，静置5分钟后，在0.5C倍率下恒流放电到3.0V，记录首次循环放电容量值。采用相同步骤使锂离子电池循环充放电800次，并记录第800次循环的放电容量值。根据下述公式计算锂离子电池的循环容量保持率：
循环容量保持率＝(第800次循环的放电容量/首次循环的放电容量)×100％。
三、测试结果
表1展示了正极活性材料表面区域和内部区域的铝元素及其含量对锂离子电池的阻抗、循环容量保持率和高温存储膨胀率的影响。表1中各实施例和对比例中使用的正极活性材料前体为钴酸锂(LiCoO 2)。表1中各实施例和对比例中使用的正极活性材料仅包含一种类型的颗粒，其中对比例1-4以及实施例1-21的正极活性材料仅包含第一颗粒(Dv50为12μm)，对比例5和实施例22的正极活性材料仅包含第二颗粒(Dv50'为4μm)。
表1
Figure PCTCN2021107115-appb-000001
结果表明，正极活性材料的表面区域的铝含量对于改善锂离子电池在高电压工作条件下的阻抗、高温存储膨胀率和循环容量保持率具有至关重要的作用。具体地，如表1所示，当正极活性材料仅包含第一颗粒(实施例1-21)或第二颗粒(实施例22)，正极活性材料表面区域包含0.01wt％至1wt％的铝元素时，可有效保证材料体相结构稳定性以及表面的扩散动力学，综合改善材料的高温循环性能和阻抗性能，显著降低锂离子电池在高电压工作条件下的阻抗和高温存储膨胀率并显著提高其循环容量保持率。当正极活性材料的表面区域的铝元素含量A为0.01wt％至0.4wt％时，锂离子电池具有格外优异的循环和存储性能。
正极活性材料的内部区域可进一步包含铝元素，其有助于进一步改善锂离子电池在 高电压工作条件下的阻抗、高温存储膨胀率和循环容量保持率。在正极活性材料表面区域包含0.01wt％至1wt％的铝元素的基础上，当正极活性材料的内部区域中的铝元素的含量A 1wt％满足A 1为0.05至2；A 1＞A；和/或1＜A 1/A＜10时，可进一步降低锂离子电池在高电压工作条件下的阻抗和高温存储膨胀率，并进一步提高锂离子电池的循环容量保持率。
图1展示了对比例1中使用的正极活性材料的电子扫描显微镜(SEM)图，其中正极活性材料表面不含铝元素。图2展示了实施例7中使用的正极活性材料的电子扫描显微镜(SEM)图，其中正极活性材料表面包含铝元素。
表2展示了正极活性材料表面区域铝元素含量、表面区域和内部区域的镧元素含量以及表面其他元素对锂离子电池的阻抗、循环容量保持率和高温存储膨胀率的影响。实施例23-47仅包含一种颗粒(第一颗粒)，其与实施例6的区别仅在于表2中所列参数。
表2
Figure PCTCN2021107115-appb-000002
Figure PCTCN2021107115-appb-000003
表2结果表明，正极活性材料的表面区域和/或内部区域可进一步包含镧元素，镧元素可与表面区域的铝元素协同改善正极活性材料的结构稳定性，同时改善锂离子的扩散与表面阻抗。在正极活性材料表面区域包含0.01wt％至1wt％的铝元素的基础上，当正极活性材料的表面区域中的镧元素含量B wt％满足B为0.01至0.8和/或0.01≤B/A≤0.8时，有助于进一步降低锂离子电池在高电压工作条件下的阻抗和高温存储膨胀率，并进一步提高锂离子电池的循环容量保持率。当正极活性材料的表面区域中的镧元素含量在0.01wt％至0.7wt％的范围内，锂离子电池具有格外优异的循环和存储性能。在正极活性材料表面区域包含0.01wt％至1wt％的铝元素的基础上，当正极活性材料的内部区域中的镧元素的含量为D wt％满足D为0.01至0.4；B＞D；和/或1＜B/D＜10时，有助于进一步降低锂离子电池在高电压工作条件下的阻抗和高温存储膨胀率，并进一步提高锂离子电池的循环容量保持率。
正极活性材料表面区域可进一步包含其他元素(例如，锂、钴、镍、锰、镁、钛、锆、氟或钇中的至少一种)，其有助于进一步优化锂离子电池在高电压工作条件下的阻抗、高温存储膨胀率和循环容量保持率。
图3展示了对比例1和实施例28中使用的正极活性材料的X射线衍射谱(XRD)，其中当正极活性材料的表面区域包含铝元素时，正极活性材料在23.0°-24.0°和32.5°-33.5°范围内出现至少两个新的特征峰，其表明正极活性材料中出现新的物相。
表3展示了正极活性材料的第一颗粒粒径、第二颗粒的粒径以及第二颗粒中的一次颗粒粒径对锂离子电池的阻抗、循环容量保持率和高温存储膨胀率的影响。对比例6和实施例48-68包含两种颗粒，即，第一颗粒和第二颗粒。对比例6的正极活性材料的第一颗粒和第二颗粒均不含铝元素。在实施例48-68中，第一颗粒的表面区域包含0.15wt％铝元素和0.10wt％的镧元素，内部区域包含0.75wt％铝元素和0.07wt％的镧元素；第二颗粒的表面区域包含0.15wt％铝元素和0.10wt％的镧元素，内部区域包含0.75wt％铝元素和0.15wt％的镧元素。
表3
Figure PCTCN2021107115-appb-000004
结果表明，当正极活性材料满足第一颗粒的Dv50在10μm至15μm的范围内；第一颗粒的Dv99在20μm至30μm的范围内；第二颗粒的Dv50'在2μm至6μm范围内；1.5≤Dv99/Dv50＜3；和/或2≤Dv50/Dv50'＜8时，可进一步改善锂离子电池在高电压工作条件下的阻抗、高温存储膨胀率和循环容量保持率。
当正极活性材料的第二颗粒包含二次颗粒且形成二次颗粒的一次颗粒的平均粒径为0.1μm至3μm时，有助于进一步改善锂离子电池在高电压工作条件下的阻抗、高温存储膨胀率和循环容量保持率。
表4展示了正极活性材料的第一颗粒中镧元素含量、第二颗粒中镧元素含量以及正极活性材料在23.0°-24.0°范围内的最强峰和32.5°-33.5°范围内的最强峰的峰强比对锂离子电池的阻抗、循环容量保持率和高温存储膨胀率的影响。实施例69-86包含两种颗粒(第一颗粒和第二颗粒)，其与实施例65的区别仅在于表3中所列参数。
表4
Figure PCTCN2021107115-appb-000005
结果表明，当正极活性材料的第一颗粒中镧元素含量为0.01wt％至0.6wt％且第二颗粒中镧元素含量为0.01wt％至0.9wt％时，可进一步改善锂离子电池在高电压工作条件下的阻抗、高温存储膨胀率和循环容量保持率。当正极活性材料的第一颗粒中镧元素含量(E wt％)与第二颗粒中镧元素含量(F wt％)满足0.5≤E/F＜1，有助于进一步改善锂离子电池在高电压工作条件下的阻抗、高温存储膨胀率和循环容量保持率。
当正极活性材料在23.0°-24.0°范围内的最强峰和32.5°-33.5°范围内的最强峰的峰强比在0.6至1.5范围内时，材料表面形成了更有效的含镧的离子导体包覆层，可进一步优化锂离子电池在高电压工作条件下的阻抗、高温存储膨胀率和循环容量保持率。
整个说明书中对“实施例”、“部分实施例”、“一个实施例”、“另一举例”、“举例”、“具体举例”或“部分举例”的引用，其所代表的意思是在本申请中的至少一个实施例或举例包含了该实施例或举例中所描述的特定特征、结构、材料或特性。因此，在整个说明书中的各处所出现的描述，例如：“在一些实施例中”、“在实施例中”、“在一个实施例中”、“在另一个举例中”，“在一个举例中”、“在特定举例中”或“举例”，其不必然是引用本申请中的相同的实施例或示例。此外，本文中的特定特征、 结构、材料或特性可以以任何合适的方式在一个或多个实施例或举例中结合。
尽管已经演示和描述了说明性实施例，本领域技术人员应该理解上述实施例不能被解释为对本申请的限制，并且可以在不脱离本申请的精神、原理及范围的情况下对实施例进行改变，替代和修改。

Claims (14)

  1. 一种正极活性材料，所述正极活性材料的表面区域的至少一部分包含铝元素，基于所述正极活性材料的重量，所述表面区域中的所述铝元素的含量为A wt％，A为0.01至1。
  2. 根据利要求1所述的正极活性材料，其中所述正极活性材料的内部区域包含铝元素，基于所述正极活性材料的重量，所述内部区域中的所述铝元素的含量为A 1 wt％，A 1满足以下条件中的至少一者：
    (a)A 1为0.05至2；
    (b)A 1＞A；
    (c)1＜A 1/A＜10。
  3. 根据权利要求1所述的正极活性材料，其中所述正极活性材料的表面区域的至少一部分进一步包含镧元素，基于所述正极活性材料的重量，所述表面的至少一部分区域中的所述镧元素的含量为B wt％，B满足以下条件中的至少一者：
    (d)B为0.01至0.8；
    (e)0.01≤B/A≤0.8。
  4. 根据权利要求1所述的正极活性材料，其中所述正极活性材料的表面区域的至少一部分进一步包含锂、钴、镍、锰、镁、钛、锆、氟或钇中的至少一种元素。
  5. 根据权利要求1所述的正极活性材料，其中所述正极活性材料的内部区域包含镧元素，基于所述正极活性材料的重量，所述内部区域中的所述镧元素的含量为D wt％，D满足以下条件中的至少一者：
    (f)D为0.01至0.4；
    (g)B＞D；
    (h)1＜B/D＜10。
  6. 根据权利要求1所述正极活性材料，其中所述正极活性材料包含第一颗粒和第二颗粒，所述第一颗粒的平均粒径大于所述第二颗粒的平均粒径。
  7. 根据权利要求6所述正极活性材料，其中所述正极活性材料满足以下条件中的至少一者：
    (i)所述第一颗粒的Dv50为10μm至15μm；
    (j)所述第一颗粒的Dv99为20μm至30μm；
    (k)所述第一颗粒的Dv50与Dv99满足：1.5≤Dv99/Dv50＜3；
    (l)所述第二颗粒的Dv50'为2μm至6μm；或
    (m)所述第一颗粒的Dv50与所述第二颗粒的Dv50'满足：2≤Dv50/Dv50'＜8。
  8. 根据权利要求6所述正极活性材料，其中所述第二颗粒包含二次颗粒，形成所述二次颗粒的一次颗粒的平均粒径为0.1μm至3μm。
  9. 根据权利要求6所述正极活性材料，其中所述第一颗粒中镧元素的含量小于所述第二颗粒中镧元素的含量。
  10. 根据权利要求6所述正极活性材料，其中基于所述正极活性材料的重量，所述第一颗粒中镧元素的含量为E wt％，所述第二颗粒中镧元素的含量为F wt％，E为0.01至0.6，F为0.01至0.9。
  11. 根据权利要求10所述正极活性材料，其中0.5≤E/F＜1。
  12. 根据权利要求3所述正极活性材料，其中采用XRD测试，所述正极活性材料在23.0°-24.0°范围内的最强峰与32.5°-33.5°范围内的最强峰的峰强比为0.6至1.5。
  13. 一种电化学装置，其包括正极、负极和电解液，所述正极包括根据权利要求1-12中任一项所述的正极活性材料。
  14. 一种电子装置，其包括根据权利要求13所述的电化学装置。
PCT/CN2021/107115 2021-03-25 2021-07-19 正极活性材料及使用其的电化学装置和电子装置 WO2022198852A1 (zh)

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001076725A (ja) * 1999-09-07 2001-03-23 Seiko Instruments Inc 非水電解質二次電池
JP2016139583A (ja) * 2015-01-29 2016-08-04 輔仁大學學校財團法人輔仁大學 リチウムイオン電池の金属勾配ドープ正極材料
CN108269997A (zh) * 2016-12-31 2018-07-10 北京当升材料科技股份有限公司 一种锂离子电池梯度正极材料及其制备方法
CN108649205A (zh) * 2018-05-15 2018-10-12 哈尔滨工业大学 一种具有变斜率浓度梯度掺杂结构的锂离子电池正极材料及其制备
CN111302407A (zh) * 2020-02-28 2020-06-19 新奥石墨烯技术有限公司 高镍四元正极材料前驱体及制备方法、高镍四元正极材料及制备方法、锂离子电池
CN112467078A (zh) * 2020-11-30 2021-03-09 宁德新能源科技有限公司 电化学装置和电子装置
CN113078309A (zh) * 2021-03-25 2021-07-06 宁德新能源科技有限公司 正极活性材料及使用其的电化学装置和电子装置

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100560540B1 (ko) * 2003-07-18 2006-03-15 삼성에스디아이 주식회사 리튬 이차 전지용 양극 활물질, 그의 제조 방법 및 그를포함하는 리튬 이차 전지
KR101244050B1 (ko) * 2009-11-05 2013-03-19 유미코르 코어-쉘 리튬 전이금속 산화물
CN103811765B (zh) * 2014-02-27 2015-12-09 广西师范大学 一种二维纳米金属氧化物复合涂层锰酸锂正极材料及其制备方法
CN107681123B (zh) * 2016-08-01 2020-03-31 宁德新能源科技有限公司 正极材料及其制备方法、正极极片及锂离子电池
CN108288692A (zh) * 2017-01-10 2018-07-17 宁德时代新能源科技股份有限公司 改性正极活性材料及其制备方法以及锂二次电池
CN108963197A (zh) * 2017-05-19 2018-12-07 宁德时代新能源科技股份有限公司 改性正极活性材料的制备方法
CN110120497B (zh) * 2018-02-07 2021-06-04 宁德新能源科技有限公司 一种活性材料和锂离子电池

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001076725A (ja) * 1999-09-07 2001-03-23 Seiko Instruments Inc 非水電解質二次電池
JP2016139583A (ja) * 2015-01-29 2016-08-04 輔仁大學學校財團法人輔仁大學 リチウムイオン電池の金属勾配ドープ正極材料
CN108269997A (zh) * 2016-12-31 2018-07-10 北京当升材料科技股份有限公司 一种锂离子电池梯度正极材料及其制备方法
CN108649205A (zh) * 2018-05-15 2018-10-12 哈尔滨工业大学 一种具有变斜率浓度梯度掺杂结构的锂离子电池正极材料及其制备
CN111302407A (zh) * 2020-02-28 2020-06-19 新奥石墨烯技术有限公司 高镍四元正极材料前驱体及制备方法、高镍四元正极材料及制备方法、锂离子电池
CN112467078A (zh) * 2020-11-30 2021-03-09 宁德新能源科技有限公司 电化学装置和电子装置
CN113078309A (zh) * 2021-03-25 2021-07-06 宁德新能源科技有限公司 正极活性材料及使用其的电化学装置和电子装置

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