WO2020134780A1 - 一种正极材料及其制备方法和用途 - Google Patents

一种正极材料及其制备方法和用途 Download PDF

Info

Publication number
WO2020134780A1
WO2020134780A1 PCT/CN2019/120585 CN2019120585W WO2020134780A1 WO 2020134780 A1 WO2020134780 A1 WO 2020134780A1 CN 2019120585 W CN2019120585 W CN 2019120585W WO 2020134780 A1 WO2020134780 A1 WO 2020134780A1
Authority
WO
WIPO (PCT)
Prior art keywords
positive electrode
electrode material
content
lithium
substrate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/CN2019/120585
Other languages
English (en)
French (fr)
Inventor
杜锐
刘勇超
王嗣慧
赵德宇
柳娜
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Contemporary Amperex Technology Co Ltd
Original Assignee
Contemporary Amperex Technology Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Contemporary Amperex Technology Co Ltd filed Critical Contemporary Amperex Technology Co Ltd
Priority to ES19901889T priority Critical patent/ES2940774T3/es
Priority to EP19901889.6A priority patent/EP3793008B1/en
Publication of WO2020134780A1 publication Critical patent/WO2020134780A1/zh
Priority to US17/135,519 priority patent/US11942636B2/en
Anticipated expiration legal-status Critical
Priority to US18/435,387 priority patent/US12176537B2/en
Ceased legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/40—Complex oxides containing nickel and at least one other metal element
    • C01G53/42—Complex oxides containing nickel and at least one other metal element containing alkali metals, e.g. LiNiO2
    • C01G53/44—Complex oxides containing nickel and at least one other metal element containing alkali metals, e.g. LiNiO2 containing manganese
    • C01G53/50—Complex oxides containing nickel and at least one other metal element containing alkali metals, e.g. LiNiO2 containing manganese of the type (MnO2)n-, e.g. Li(NixMn1-x)O2 or Li(MyNixMn1-x-y)O2
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • 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
    • H01M4/366—Composites as layered products
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/50—Solid solutions
    • C01P2002/52—Solid solutions containing elements as dopants
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/50—Agglomerated particles
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
    • C01P2004/82—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases
    • C01P2004/84—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases one phase coated with the other
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/12—Surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the invention relates to the field of electrochemistry, in particular to a positive electrode material, its preparation method and use.
  • Lithium ion batteries have the advantages of high specific energy, wide application temperature range, low self-discharge rate, long cycle life, good safety performance, and no pollution. They have been used in various fields. Lithium-ion batteries have been gradually tried to replace traditional diesel locomotives as the energy system of automobiles. However, currently commonly used lithium iron phosphate (LiFePO 4 ), low nickel ternary (LiNi 1/3 Co 1/3 Mn 1/3 O 2 ), etc., due to the limitations of the nature of the material itself, can not fully meet the lithium ion of power batteries The energy density requirements of battery positive materials.
  • the high-nickel ternary cathode material is one of the main research objects of power batteries.
  • the direct side reaction between the positive electrode active material and the electrolyte is also significantly intensified, and the cycle performance is significantly deteriorated, which is one of the bottlenecks in the commercialization of mass production.
  • the object of the present invention is to provide a cathode material and a lithium ion battery using the same, by providing a cathode with lower powder resistivity and lower surface residual lithium
  • the material reduces the DC resistance and gas production of the lithium-ion battery, and ensures good cycle performance and rate performance of the high-capacity battery.
  • one aspect of the present invention provides a cathode material including a substrate, the substrate including secondary particles composed of primary particles, and the molecular formula of the substrate is Li x Ni y Co z M k Me p O r A m , where 0.95 ⁇ x ⁇ 1.05, 0.50 ⁇ y ⁇ 0.98, 0 ⁇ z ⁇ 0.3, 0 ⁇ k ⁇ 0.4, 0 ⁇ p ⁇ 0.05, 1 ⁇ r ⁇ 2, 0 ⁇ m ⁇ 2, m+r ⁇ 2, M is selected from Mn and/or Al, Me is selected from Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, Sr, Sb, Y, W, Nb, Al One or more combinations, A is selected from one or more combinations of F, Cl, Br;
  • An oxide coating layer is provided on the surface of the substrate, and the oxide coating layer includes a coating element selected from Al, Ba, Zn, Ti, Zr, Mg, W, Y, Si, A combination of one or more of Sn, B, Co, P;
  • the powder resistivity ⁇ of the positive electrode material under a pressure of 12 MPa is 10 ⁇ *cm to 5000 ⁇ *cm, preferably 10 ⁇ *cm to 2000 ⁇ *cm.
  • Another aspect of the present invention provides an electrochemical energy storage device including the positive electrode material.
  • the present invention has the following beneficial effects:
  • the positive electrode material of the present invention controls the powder resistivity of the positive electrode material in an appropriate range by doping and surface coating in a high nickel base material, while reducing the specific surface area of the positive electrode active material, reducing the amount of lithium on the surface, and improving
  • the polarization problem of the positive electrode material reduces the DC resistance of the lithium ion battery, at the same time, effectively reduces the side reaction between the positive electrode material and the electrolyte, suppresses the gas production problem of the battery, improves the volume energy density of the battery, optimizes the cycle performance and rate performance .
  • the lithium ion battery of the present invention and its preparation method are described in detail below.
  • a first aspect of the present invention provides a positive electrode material, including a substrate, the substrate including secondary particles composed of primary particles, and the molecular formula of the substrate is Li x Ni y Co z M k Me p O r A m , Where 0.95 ⁇ x ⁇ 1.05, 0.70 ⁇ y ⁇ 0.98, 0 ⁇ z ⁇ 0.2, 0 ⁇ k ⁇ 0.2, 0 ⁇ p ⁇ 0.05, 1 ⁇ r ⁇ 2, 0 ⁇ m ⁇ 2, m+r ⁇ 2 , M is selected from Mn and/or Al, Me is selected from one or a combination of Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, Sr, Sb, Y, W, Nb, Al, A is a combination of one or more selected from F, Cl, Br;
  • An oxide coating layer is provided on the surface of the substrate, and the oxide coating layer includes a coating element selected from Al, Ba, Zn, Ti, Zr, Mg, W, Y, Si, A combination of one or more of Sn, B, Co, P;
  • the powder resistivity ⁇ of the positive electrode material under a pressure of 12 MPa is 10 ⁇ *cm to 5000 ⁇ *cm.
  • the layered lithium nickel cobalt manganese oxide has a higher theoretical gram capacity due to the higher Ni content, but due to the unstable nickel valence, as Ni increases, the relative content of Ni 4+ will also increase Therefore, it will cause side reaction of the electrolyte on the surface of the positive electrode material.
  • the base material in the present invention includes secondary particles composed of primary particles.
  • the oxide used is a simple oxide with excellent ion conductivity and relatively poor conductivity, it will cause the polarization of the positive electrode material to increase and deteriorate the cycle performance of the battery. Therefore, in the present invention, the surface of the substrate is covered with oxidation At the same time as the modification of the substance, the use of specific doping elements and optimization of the doping dose are used to control the powder resistivity of the positive electrode material between 10 ⁇ *cm and 5000 ⁇ *cm, so that the intrinsic electronic conductivity of the positive electrode material is high, and The amount of residual lithium and other impurities on the surface are less, which effectively reduces the side reaction between the material and the electrolyte, and reduces the interface resistance between the electrolyte and the positive electrode active material; thereby greatly reducing the polarization of the battery, thereby improving the cycle performance and rate performance of the battery .
  • the range of the powder resistivity ⁇ of the cathode material under a pressure of 12 MPa may be 10 ⁇ *cm ⁇ 5000 ⁇ *cm, 10 ⁇ *cm ⁇ 3000 ⁇ *cm, 10 ⁇ *cm ⁇ 2000 ⁇ *cm, 10 ⁇ *cm ⁇ 1000 ⁇ *cm, 10 ⁇ *cm ⁇ 500 ⁇ *cm, 10 ⁇ *cm ⁇ 100 ⁇ *cm, 10 ⁇ *cm ⁇ 50 ⁇ *cm, 10 ⁇ *cm ⁇ 30 ⁇ *cm, 30 ⁇ *cm ⁇ 50 ⁇ *cm, 50 ⁇ * cm ⁇ 100 ⁇ *cm, 100 ⁇ *cm ⁇ 200 ⁇ *cm, 200 ⁇ *cm ⁇ 300 ⁇ *cm, 300 ⁇ *cm ⁇ 500 ⁇ *cm, 500 ⁇ *cm ⁇ 1000 ⁇ *cm, 1000 ⁇ *cm ⁇ 2000 ⁇ *cm, 2000 ⁇ *cm ⁇ 3000 ⁇ *cm or 3000 ⁇ *cm ⁇ 5000 ⁇ *cm.
  • the powder resistivity of the positive electrode active material under a pressure of 12 MPa can be measured using a known powder resistivity test method.
  • the four-probe method is used to test the powder resistivity of the positive electrode active material at a pressure of 12 MPa.
  • the test method includes: adding 0.4 g of the positive electrode active material powder to a sample mold (internal diameter of 11.28 mm), using a press The powder is applied with a pressure of 12 MPa. After the pressure is stabilized, the resistivity of the powder of the positive electrode active material under the pressure of 12 MPa is read by a resistivity meter.
  • the content Mv of the coating element per unit volume of the cathode material may be 400 ⁇ g/cm 3 ⁇ 15000 ⁇ g/cm 3 , 400 ⁇ g/cm 3 ⁇ 12000 ⁇ g/cm 3 , 800 ⁇ g/cm 3 ⁇ 10000 ⁇ g/cm 3 ⁇ 400 ⁇ g/cm 3 ⁇ 600 ⁇ g/cm 3 ⁇ 600 ⁇ g/cm 3 ⁇ 800 ⁇ g/cm 3 ⁇ 800 ⁇ g/cm 3 ⁇ 1000 ⁇ g/cm 3 ⁇ 1000 ⁇ g/cm 3 ⁇ 2000 ⁇ g/cm 3 ⁇ 2000 ⁇ g/cm 3 ⁇ 4000 ⁇ g / cm 3, 4000 ⁇ g / cm 3 ⁇ 6000 ⁇ g / cm 3, 6000 ⁇ g / cm 3 ⁇ 8000 ⁇ g / cm 3, 8000 ⁇ g / cm 3 ⁇ 10000 ⁇ g / cm 3, 10000 ⁇ g / cm 3 ⁇ 12000 ⁇ g / cm
  • the content Mv of the coating element in the unit volume of the positive electrode material is in the above range, it can be ensured that under the system of different volume particle size distribution, the surface modification of the secondary particles and the polarization problem of the positive electrode material Compatible adjustments have been made to effectively improve the gas production of high-capacity batteries, optimize cycle and rate performance.
  • the ratio of the powder resistivity ⁇ of the positive electrode material to the content Mv of the coating element per unit volume of the positive electrode material satisfies: ⁇ /Mv ⁇ 1( ⁇ * cm 4 / ⁇ g), ⁇ /Mv ⁇ 0.8( ⁇ *cm 4 / ⁇ g), ⁇ /Mv ⁇ 0.6( ⁇ *cm 4 / ⁇ g ), or ⁇ / Mv ⁇ 0.5 ( ⁇ * cm 4 / ⁇ g).
  • the unit of the powder resistivity of the positive electrode material may be ⁇ *cm
  • the unit of the content of the coating element in the unit volume of the positive electrode material may be ⁇ g*cm -3 .
  • the smaller the ratio of ⁇ /Mv the more the content of the coating element, the overall polarization of the cathode material is smaller, the side reactions are less, and the cycle is better.
  • the coating element is at least two or more selected from Al, Ba, Zn, Ti, Zr, Mg, W, Y, Si, Sn, B, Co, P, and the like.
  • an oxide coating layer may be provided on the surface of the substrate, the oxide coating layer may be located on the surface of the secondary particles, and the coating element in the oxide coating layer may be in the second Surface distribution of secondary particles.
  • the coating element may exist in the form of its oxide, and the oxide coating layer may contain an oxide formed by at least two or more of the foregoing coating elements , which can improve the stability of the coating layer on the surface of the substrate, make the coating layer have certain ion conductivity and conductivity, reduce the impact of the coating layer on the polarization of the cathode material, and effectively avoid high
  • the direct contact between the nickel-containing substrate and the electrolyte reduces the side reaction between the substrate and the electrolyte, avoids a large amount of gas in the circulation process, and at the same time ensures that the battery has low impedance and excellent cycle and rate performance.
  • the surface of the primary particles inside the secondary particles may be coated with coating elements, which may exist in the form of oxides; A coating element may also be distributed at the grain boundary between the primary particles, and this part of the coating element may exist in the form of its oxide.
  • the secondary particles are formed by the close accumulation of several primary particles. During the circulation process, the secondary particles will expand and contract in volume, resulting in an increase in the spacing between the primary particles inside the secondary particles, exposing a large amount of uncoated Fresh surface, so there is a risk of side reactions with the electrolyte.
  • the coating layer is provided on the surface of the secondary particles, at least a part of the surface of the primary particles or the grain boundary between the adjacent primary particles is further coated, which can enhance the density of the secondary particles and improve the internal
  • the force between the primary particles further optimizes the gas production during the cycle.
  • the content of the coating element in the oxide coating layer may account for more than 60wt%, more than 70wt%, more than 80wt% of the total coating element mass in the positive electrode active material, Above 90 wt%, preferably 80 wt% to 98 wt%.
  • the mass of the coating element distributed on the surface of the secondary particles accounts for more than a certain proportion of the total coating element mass in the positive electrode active material. The surface modification of the high-nickel cathode material is remarkable, and it has a good effect on suppressing the gas production of the battery.
  • the positive electrode material is a lithium transition metal oxide, and due to the segregation of a certain element content during the preparation process, the lithium element in the molecular formula of the positive electrode material may be depleted in lithium to a certain extent Or in the case of lithium-rich, when the relative content of lithium element is in the range of 0.95 ⁇ x ⁇ 1.05, it has little effect on the capacity of the positive electrode material.
  • the relative content of lithium element may be 0.95 ⁇ x ⁇ 1,1 ⁇ x ⁇ 1.05.
  • the base material is a lithium transition metal oxide with a high nickel content.
  • the molecular formula of the base material 0.50 ⁇ y ⁇ 0.98, 0 ⁇ z ⁇ 0.3, 0 ⁇ k ⁇ 0.4, 0 ⁇ p ⁇ 0.05.
  • the substrate may be LiNi 0.5 Co 0.2 Mn 0.3 O 2 , LiNi 0.5 Co 0.25 Mn 0.25 O 2 , LiNi 0.55 Co 0.15 Mn 0.3 O 2 , LiNi 0.55 Co 0.1 Mn 0.35 O 2 , LiNi 0.55 Co 0.05 Mn 0.4 O 2 , LiNi 0.6 Co 0.2 Mn 0.2 O 2 , LiNi 0.75 Co 0.1 Mn 0.15 O 2 , LiNi 0.8 Co 0.1 Mn 0.1 O 2 , LiNi 0.85 Co 0.05 Mn 0.1 O 2 , LiNi 0.88 Co 0.05 Mn 0.07 O 2 , LiNi 0.9 Co 0.05 Mn 0.05 O 2 may also be a material in which the above substances are partially substituted and modified by Me and/or A, where Me is selected from Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, Sr , Sb, Y, W, Nb, Al in one or more combinations, A is selected from
  • a positive electrode active material with a high nickel content is selected from the positive electrode active materials. Since the higher the relative content of the Ni element and the higher the theoretical gram capacity of the material, the volume energy density of the battery can be effectively improved; by controlling the high nickel positive electrode activity The surface compactness of the secondary particles of the material and the compressive strength of the single particles can effectively solve the gas generation problem of the high-capacity battery during the cycling process and improve the energy density and service life of the battery.
  • the positive electrode material provided by the present invention in the structural formula of the substrate, 0.80 ⁇ y ⁇ 0.98, 0 ⁇ z ⁇ 0.1, 0 ⁇ k ⁇ 0.1, 0 ⁇ p ⁇ 0.03.
  • the lithium nickel cobalt manganese oxide of the base material of the positive electrode material with a Ni content of 0.80 to 0.98 has a higher residual lithium content on the surface
  • the Dv50 of the secondary particles may be 5 ⁇ m to 18 ⁇ m, and the particle size of the primary particles may range from 0.1 ⁇ m to 1 ⁇ m.
  • the Dv50 generally refers to the corresponding particle size when the cumulative volume distribution percentage of the sample reaches 50%.
  • the Dv50 of the secondary particles may be 5 ⁇ m to 18 ⁇ m, 6 ⁇ m to 15 ⁇ m, 8 ⁇ m to 14 ⁇ m, 9 ⁇ m to 11 ⁇ m, 10 ⁇ m to 12 ⁇ m, 12 ⁇ m to 14 ⁇ m, 14 ⁇ m to 16 ⁇ m, or 16 ⁇ m to 18 ⁇ m;
  • the particle size range may be 0.1 ⁇ m to 1 ⁇ m, 0.1 ⁇ m to 0.9 ⁇ m, 0.2 ⁇ m to 0.8 ⁇ m, 0.2 ⁇ m to 0.5 ⁇ m.
  • the positive electrode material of the present invention provided herein, specific surface area of the positive electrode material is 0.1m 2 /g ⁇ 0.8m 2 / g. Specifically, it may be 0.1m 2 /g ⁇ 0.8m 2 /g,0.1m 2 /g ⁇ 0.2m 2 /g,0.2m 2 /g ⁇ 0.3m 2 /g,0.3m 2 /g ⁇ 0.4m 2 /g,0.4m 2 /g ⁇ 0.5m 2 /g,0.5m 2 /g ⁇ 0.6m 2 /g,0.6m 2 /g ⁇ 0.7m 2 / g, or 0.7m 2 /g ⁇ 0.8m 2 / g.
  • the average particle size and BET specific surface area of the positive electrode material are set in the above range, which can effectively reduce the contact area of the positive electrode material and the electrolyte, even under the action of high voltage or strong oxidizability, the electrolyte in the positive electrode active material Less side reactions occur on the surface, which effectively suppresses gas production problems and reduces heat production.
  • the safety performance and cycle performance of the battery are effectively improved; at the same time, the path of lithium ion insertion and extraction in the positive electrode active material particles during charging and discharging will not pass Long, to further optimize the battery's dynamic performance.
  • the content of Li 2 CO 3 in the residual lithium on the surface of the cathode material (that is, the content of the mass of Li 2 CO 3 in the residual lithium on the surface of the substrate relative to the total mass of the cathode material is less than 3000 ppm, preferably, the content of Li 2 CO 3 in the residual lithium is less than 2000 ppm.
  • the content of LiOH in the residual lithium on the surface of the positive electrode material ie, the mass of LiOH in the residual lithium on the surface of the positive electrode material relative to the total of the positive electrode material Mass content
  • is less than 5000 ppm preferably, the content of LiOH in the residual lithium is less than 4000 ppm.
  • the base material of the cathode material of the present invention is a high nickel content lithium nickel cobalt manganese oxide, the surface residual lithium content is usually higher, in After the coating layer is provided on the surface of the substrate, the amount of residual lithium on the surface can be effectively reduced, but it will cause a large polarization of the positive electrode material. Choosing a positive electrode material with a residual lithium on the surface in the above range can be effectively compatible with gas generation problems and polarization problems. Obtain a battery with higher capacity, less significant gas production problems, and excellent cycle and rate performance.
  • the content of Li 2 CO 3 in the residual lithium on the surface of the positive electrode material is less than the content of LiOH.
  • residual lithium (LiOH, Li 2 O) on the surface easily reacts with moisture in the air, CO 2 and the like, and the reaction product is Li 2 CO 3 and the like. The higher the Li 2 CO 3 , the more violent the reaction, and the more serious the gas production problem of the corresponding battery.
  • a second aspect of the present invention provides a method for preparing a cathode material provided in the first aspect of the present invention, including:
  • a coating layer is formed on the surface of the substrate.
  • the preparation method of the positive electrode material provided by the present invention may include: providing a substrate.
  • the method for providing the substrate should be known to those skilled in the art. For example, it may include mixing and sintering the raw materials of the substrate to provide the substrate.
  • a person skilled in the art can select a suitable raw material and ratio of the base material according to the element composition of the base material.
  • the raw materials of the substrate may include a ternary material precursor of nickel cobalt manganese and/or aluminum, a lithium source, an M source, a Me source, an A source, etc.
  • the ratio between the raw materials generally refers to the elements in the substrate The ratio.
  • the ternary material precursor may include but not limited to Ni 0.5 Co 0.2 Mn 0.3 (OH) 2 , Ni 0.5 Co 0.25 Mn 0.25 (OH) 2 , Ni 0.55 Co 0.15 Mn 0.3 (OH) 2 , Ni 0.55 Co 0.1 Mn 0.35 (OH) 2 , Ni 0.55 Co 0.05 Mn 0.4 (OH) 2 , Ni 0.6 Co 0.2 Mn 0.2 (OH) 2 , Ni 0.75 Co 0.1 Mn 0.15 (OH) 2 , Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 , Ni 0.88 Co 0.05 Mn 0.07 (OH) 2 , 0.9Ni 0.8 Co 0.2 (OH) 2 ⁇ 0.1Al 2 (OH) 3 , 0.9Ni 0.9 Co 0.05 Mn 0.05 (OH) 2 ⁇ 0.1Al 2 (OH) 3 , the lithium source may be a lithium-containing compound, and the lithium-containing compound may be one or more of LiOH ⁇ H 2 O, LiOH, Li 2 CO 3
  • the Me source may generally be a compound containing an element of Me, and the compound containing an element of Me may be a compound containing Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, Sr, Sb, Y, W, One or more of oxides, nitrates, and carbonates of at least one element in Nb and Al.
  • the source A may be a compound containing element A, and the compound containing element A may include but not Limited to a combination of one or more of LiF, NaCl, NaBr, etc.
  • the sintering conditions may be 800° C. and the oxygen concentration ⁇ 20%.
  • the method for preparing a positive electrode material provided by the present invention may further include: forming a coating layer on the surface of the substrate.
  • the method of forming a coating layer on the surface of the substrate should be known to those skilled in the art, for example, it may include: sintering the substrate in the presence of a compound containing a coating element to form on the surface of the substrate Cladding.
  • a person skilled in the art can select a suitable kind, compounding ratio and sintering condition of the compound containing the coating element according to the parameters of the coating layer composition, the powder resistivity of the base material and the like.
  • the compound containing the coating element may include but not limited to Al 2 O 3 , ZnO, ZrO 2 , TiO 2 , MgO, WO 3 , Y 2 O 3 , Co 2 O 3 , Ba(NO 3 ) 2 , Co 2 O 3 , P 2 O 5 , H 3 BO 3 and the like, and for example, the amount of the coating element may be 0.01 wt% to 0.5 wt% of the mass of the substrate
  • the sintering condition may be high-temperature sintering at 200°C to 700°C.
  • a third aspect of the present invention provides an electrochemical energy storage device including the positive electrode active material provided by the first aspect of the present invention.
  • the electrochemical energy storage device may be a supercapacitor, a lithium ion battery, a lithium metal battery, a sodium ion battery, or the like.
  • the electrochemical energy storage device is a lithium ion battery are shown, but the present invention is not limited thereto.
  • a lithium-ion battery it may include a positive pole piece, a negative pole piece, a separation film spaced between the positive pole piece and the negative pole piece, and an electrolyte, wherein the positive pole piece includes the one provided in the first aspect of the present invention Positive active material.
  • the method for preparing the lithium-ion battery should be known to those skilled in the art.
  • the positive pole piece, the separator, and the negative pole piece can each be a layered body, so that they can be cut to the target size in turn Stacked, it can also be wound to the target size for the formation of batteries, and can be further combined with the electrolyte to form a lithium-ion battery.
  • the positive electrode tab usually includes a positive electrode current collector and a positive electrode material layer on the positive electrode current collector, and the positive electrode material layer may include the positive electrode active material and the bonding material provided in the first aspect of the present invention.
  • Agent conductive agent.
  • a person skilled in the art may select a suitable method to prepare the positive electrode sheet.
  • the method may include the steps of mixing a positive electrode active material, a binder, and a conductive agent to form a slurry, and then coating the positive electrode current collector.
  • the binder generally includes a fluorine-containing polyolefin-based binder.
  • the fluorine-containing polyolefin-based binder is usually in It has good solubility in water.
  • the fluorine-containing polyolefin binder may include, but not limited to, polyvinylidene fluoride (PVDF), vinylidene fluoride copolymer, etc. or their modification (for example, carboxylic acid, Modified derivatives such as acrylic acid and acrylonitrile.
  • PVDF polyvinylidene fluoride
  • vinylidene fluoride copolymer etc.
  • their modification for example, carboxylic acid, Modified derivatives such as acrylic acid and acrylonitrile.
  • the mass percentage content of the binder may be due to the poor conductivity of the binder itself, so the amount of the binder may not be too high.
  • the mass percentage content of the binder in the positive electrode active material layer is less than or equal to 2 wt%, so as to obtain a lower pole piece resistance.
  • the conductive agent of the positive pole piece may be various conductive agents suitable for lithium ion (secondary) batteries in the art, for example, may include but not limited to acetylene black, conductive carbon black, carbon fiber (VGCF), carbon nanotubes (CNT), Ketjen Black, etc. one or more combinations.
  • the weight of the conductive agent may account for 1 wt% to 10 wt% of the total mass of the positive electrode material layer. More preferably, the weight ratio of the conductive agent to the positive electrode active material in the positive electrode sheet is greater than or equal to 1.5:95.5.
  • the positive electrode current collector of the positive electrode tab can generally be a layered body, the positive electrode current collector is usually a structure or part that can collect current, and the positive electrode current collector can be various
  • the material of the positive electrode current collector of the lithium ion battery for example, the positive electrode current collector may include but not limited to metal foil and the like, and more specifically may include but not limited to copper foil, aluminum foil and the like.
  • the negative electrode tab usually includes a negative electrode current collector and a negative electrode active material layer on the surface of the negative electrode current collector, and the negative electrode active material layer usually includes a negative electrode active material.
  • the negative electrode active material may be various materials suitable for negative electrode active materials of lithium ion batteries in the art, for example, may include but not limited to graphite, soft carbon, hard carbon, carbon fiber, mesophase carbon microspheres, silicon-based materials , Tin-based materials, lithium titanate or other metals that can be alloyed with lithium, etc., in one or more combinations.
  • the graphite may be selected from one or more of artificial graphite, natural graphite and modified graphite;
  • the silicon-based material may be selected from elemental silicon, silicon oxide compound, silicon carbon composite, silicon alloy One or more combinations of the above;
  • the tin-based material may be selected from one or more combinations of elemental tin, tin oxide compounds, and tin alloys.
  • the negative electrode current collector is usually a structure or part that collects current.
  • the negative electrode current collector may be various materials suitable for use as a negative electrode current collector of a lithium ion battery in the art.
  • the negative electrode current collector may include but is not limited to The metal foil and the like may more specifically include but not limited to copper foil and the like.
  • the separator may be various materials suitable for the separator of the lithium ion battery in the art, for example, may include but not limited to polyethylene, polypropylene, polyvinylidene fluoride, aramid, and poly One or more combinations of ethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, polyester and natural fiber.
  • the electrolyte may be various electrolytes suitable for lithium ion batteries in the art, for example, the electrolyte generally includes an electrolyte and a solvent, and the electrolyte may generally include a lithium salt and the like, more specifically
  • the lithium salt may be an inorganic lithium salt and/or an organic lithium salt, etc., and may specifically include but not limited to, the lithium salt may be selected from LiPF 6 , LiBF 4 , LiN(SO 2 F) 2 (abbreviated as LiFSI ), LiN(CF 3 SO 2 ) 2 (abbreviated as LiTFSI), LiClO 4 , LiAsF 6 , LiB(C 2 O 4 ) 2 (abbreviated as LiBOB), LiBF 2 C 2 O 4 (abbreviated as LiDFOB) One or more combinations.
  • the concentration of the electrolyte may be between 0.8 mol/L and 1.5 mol/L.
  • the solvent may be any solvent suitable for an electrolyte of a lithium ion battery in the art.
  • the solvent of the electrolyte is usually a non-aqueous solvent, preferably an organic solvent, and may specifically include but not limited to ethylene carbonate, carbonic acid Propylene ester, butylene carbonate, pentenyl carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, etc. or a combination of one or more of their halogenated derivatives.
  • one or more of the method steps mentioned in the present invention does not exclude that there may be other method steps before or after the combination step or that other method steps may be inserted between these explicitly mentioned steps unless otherwise Explained; It should also be understood that the combined connection relationship between one or more devices/devices mentioned in the present invention does not exclude that there may be other devices/devices or those mentioned explicitly in these before and after the combined device/device Other devices/apparatuses can also be inserted between the two devices/apparatuses unless otherwise stated.
  • each method step is only a convenient tool to identify each method step, not to limit the order of each method step or to limit the scope of the present invention, the change or adjustment of its relative relationship, in If the technical content is not substantially changed, it should be regarded as the scope of the invention.
  • the batteries in the examples are prepared according to the following methods:
  • Step 1 Preparation of substrate precursor
  • Step 2 The substrate precursor, Li-containing compound, Me-containing compound, and Y-containing compound obtained in step 1 are placed in a mixing device for mixing, and then placed in an atmosphere furnace for sintering to obtain a base material for a positive electrode material ;
  • Step 3 Place the positive electrode active material matrix and a certain amount of compound containing the coating element in the mixing equipment for mixing, and then place it in an atmosphere furnace for sintering to form a coating layer of the positive electrode active material, which is the finished positive electrode material.
  • Step 1 Mix the above positive electrode material, binder polyvinylidene fluoride, and conductive agent acetylene black according to a mass ratio of 98:1:1, add N-methylpyrrolidone (NMP), and stir evenly under the action of a vacuum mixer to obtain a positive electrode Slurry; evenly coat the positive electrode slurry on the pole piece, the areal density is 0.1mg/mm 2 ⁇ 0.3mg/mm 2 ;
  • NMP N-methylpyrrolidone
  • Step 2 The coated pole piece is dried in an oven at 100° C. to 130° C., cold pressed, and slit to obtain a positive pole piece.
  • the organic solvent is a mixed liquid containing ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC), wherein the volume ratio of EC, EMC and DEC is 20:20:60.
  • EC ethylene carbonate
  • EMC ethyl methyl carbonate
  • DEC diethyl carbonate
  • the concentration of the lithium salt is 1 mol/L.
  • the positive pole piece, the separator and the negative pole piece in order, so that the separator is placed between the positive and negative pieces to play the role of isolation, and then wound into a square bare cell, put into the aluminum plastic film, and then After baking and removing water at 80°C, the corresponding non-aqueous electrolyte is injected and sealed, and after standing, hot and cold pressing, formation, jigs, and volume division, the finished battery is obtained.
  • Nickel sulfate, manganese sulfate, cobalt sulfate molar ratio of 8:1:1 is configured into a solution with a concentration of 1mol/L, and the hydroxide nickel co-precipitation technology is used to prepare lithium nickel transition metal oxide A with a larger particle size.
  • the precursor Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 .
  • the particle size can be controlled by controlling the reaction time, pH during co-precipitation, and ammonia concentration;
  • the large particle nickel-cobalt-manganese ternary material precursor Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 and the Li-containing compound LiOH ⁇ H 2 O were placed in the mixing equipment for mixing, and then placed in an atmosphere furnace at 800°C for sintering After cooling, it is the base material of the ternary material by mechanical grinding; the positive electrode active material matrix and the additive of 0.3wt% Al 2 O 3 are placed in the mixing equipment for mixing, and then placed in an atmosphere furnace for sintering at 450°C , To form the coating layer of the positive electrode active material, which is the finished material.
  • the preparation method of the positive electrode material of Example 1 is basically the same, except that: the relative contents of Ni, Co, Mn, and Al elements in the precursor are different, and substrates with different components are prepared; the reaction time is adjusted, and the coprecipitation time PH value, ammonia concentration, change the size of primary particles and secondary particles; at the same time, change the type of coating layer, coating amount and heat treatment temperature, the specific characteristics of the positive electrode material in the above examples are shown in Table 1, and finally implemented The positive electrode materials in Examples 2-14.
  • the preparation method of Comparative Example 1 refers to the preparation method of Example 1 as described above, except that the surface of the sample in the comparative example is coated with V 2 O 5 .
  • the preparation method of Comparative Example 2 refers to the preparation method of Example 17 as described above, except that the surface of the sample in the Comparative Example is coated with Fe 2 O 3 .
  • the preparation method of Comparative Example 3 refers to the preparation method of Example 17 as described above, except that in the coating process of the sample in the comparative example, the sintering temperature of the additive Al 2 O 3 was 600° C.
  • the positive electrode materials prepared in the examples and comparative examples were tested for powder resistivity.
  • the test method is as follows:
  • the four-probe method was used to test the powder resistivity of the positive electrode active material under a pressure of 12 MPa.
  • the test method included: adding 0.4 g of the positive electrode active material powder to a sample mold (internal diameter 11.28 mm), and applying 12 MPa to the powder through a press After the pressure is stabilized, read the powder resistivity of the positive electrode active material under a pressure of 12MPa through a resistivity meter.
  • the results of Examples 1 to 14 and Comparative Examples 1 to 3 are shown in Table 1.
  • adjusting the content of the coating element in the secondary particles per unit volume can further optimize the powder resistivity of the positive electrode material, so that the cycle performance of the lithium ion battery is further improved.
  • the two coatings are evenly distributed on the surface of the cathode material, which can isolate the side reaction of the cathode material and the electrolyte, and at the same time ensure the powder resistance of the cathode material The rate is low, thereby enhancing the surface stability and making the surface of the positive electrode material have both good ion conductivity and conductivity, so the cycle performance is better.
  • the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Composite Materials (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)

Abstract

一种正极材料及其制备方法和用途，涉及电化学领域。该正极材料包括基材，所述基材包括由一次颗粒组成的二次颗粒，所述基材表面设有氧化物包覆层。该正极材料通过在高镍基材中进行掺杂和表面包覆，控制正极材料的粉体电阻率在适当的范围，同时降低正极活性材料的比表面积、降低表面的杂锂量，改善正极材料的极化问题，降低锂离子电池的直流阻抗，同时，有效降低正极材料与电解液之间的副反应，抑制电池的产气问题，提高电池的体积能量密度、优化循环性能和倍率性能。

Description

一种正极材料及其制备方法和用途 技术领域
本发明涉及电化学领域，特别是涉及一种正极材料及其制备方法和用途。
背景技术
随着能源危机以及环境问题的不断升级，开发新型绿色能源已迫在眉睫。锂离子电池具有比能量高、应用温度范围宽、自放电率低、循环寿命长、安全性能好、无污染等优点，现已被应用于各个领域中。锂离子电池作为汽车的能源系统取代传统内燃机车已在世界各地逐步尝试。然而目前常用的磷酸铁锂(LiFePO 4)、低镍三元(LiNi 1/3Co 1/3Mn 1/3O 2)等，由于受到材料本身的性质局限，不能完全满足动力电池对锂离子电池正极材料能量密度的需求。提高高镍三元正极材料的镍含量可以提升电池的能量密度，因此，高镍三元正极材料是目前动力电池的主要研究对象之一。但是，随着镍含量的增加，正极活性材料与电解液直接的副反应也明显加剧，循环性能明显恶化，是目前量产商业化的瓶颈之一。
发明内容
鉴于以上所述现有技术的缺点，本发明的目的在于提供一种正极材料及使用该正极材料的锂离子电池，通过提供一种具有较低粉体电阻率、表面残锂量较低的正极材料，降低锂离子电池的直流阻抗和产气量，保证高容量电池的循环性能和倍率性能良好。
为实现上述目的及其他相关目的，本发明一方面提供一种正极材料，包括基材，所述基材包括由一次颗粒组成的二次颗粒，所述基材的分子式为Li xNi yCo zM kMe pO rA m，其中，0.95≤x≤1.05，0.50≤y≤0.98，0≤z≤0.3，0≤k≤0.4，0≤p≤0.05，1≤r≤2，0≤m≤2，m+r≤2，M选自Mn和/或Al，Me选自Zr、Zn、Cu、Cr、Mg、Fe、V、Ti、Sr、Sb、Y、W、Nb、Al中的一种或多种的组合，A选自F、Cl、Br中的一种或多种的组合；
所述基材表面设有氧化物包覆层，所述氧化物包覆层包括包覆元素，所述包覆元素选自Al、Ba、Zn、Ti、Zr、Mg、W、Y、Si、Sn、B、Co、P中的一种或多种的组合；
所述正极材料在12MPa压力下的粉体电阻率ρ为10Ω*cm～5000Ω*cm，优选为10Ω*cm～2000Ω*cm。
本发明另一方面提供一种电化学储能装置，包括所述的正极材料。
相对于现有技术，本发明具有以下有益效果：
本发明的正极材料通过在高镍基材中进行掺杂和表面包覆，控制正极材料的粉体电阻率 在适当的范围，同时降低正极活性材料的比表面积、降低表面的杂锂量，改善正极材料的极化问题，降低锂离子电池的直流阻抗，同时，有效降低正极材料与电解液之间的副反应，抑制电池的产气问题，提高电池的体积能量密度、优化循环性能和倍率性能。
具体实施方式
下面详细说明本发明的锂离子电池及其制备方法。
本发明第一方面提供一种正极材料，包括基材，所述基材包括由一次颗粒组成的二次颗粒，所述基材的分子式为Li xNi yCo zM kMe pO rA m，其中，0.95≤x≤1.05，0.70≤y≤0.98，0≤z≤0.2，0≤k≤0.2，0≤p≤0.05，1≤r≤2，0≤m≤2，m+r≤2，M选自Mn和/或Al，Me选自Zr、Zn、Cu、Cr、Mg、Fe、V、Ti、Sr、Sb、Y、W、Nb、Al中的一种或多种的组合，A选自F、Cl、Br中的一种或多种的组合；
所述基材表面设有氧化物包覆层，所述氧化物包覆层包括包覆元素，所述包覆元素选自Al、Ba、Zn、Ti、Zr、Mg、W、Y、Si、Sn、B、Co、P中的一种或多种的组合；
所述正极材料在12MPa压力下的粉体电阻率ρ为10Ω*cm～5000Ω*cm。
通常来说，层状锂镍钴锰氧化物由于Ni含量较高，其理论克容量较高，但是由于镍的价态不稳定，随着Ni的升高，Ni 4+的相对含量也会增加，因此会导致电解液在正极材料表面发生副反应。本发明中的基材包括由一次颗粒组成的二次颗粒，通过在基材的表面设置氧化物包覆层，能够有效钝化高镍锂过渡金属氧化物的表面，隔绝电解液，降低活性物质表面残锂量，改善产气问题。如果所使用的氧化物为导离子性能优良、导电子性能相对较差的简单氧化物，会引起正极材料的极化增加，恶化电池的循环性能，所以本发明中通过在基材表面包覆氧化物改性的同时，配合使用特定的掺杂元素并优化掺杂剂量，控制正极材料的粉体电阻率在10Ω*cm～5000Ω*cm，使得该正极材料的本征电子导电率较高，并且表面的残锂量和其他杂质更少，有效减少材料与电解液副反应，降低电解液与正极活性物质的界面电阻；从而大幅降低了电池的极化，从而改善了电池的循环性能和倍率性能。
在本发明一些实施方式中，所述正极材料在12MPa压力下的粉体电阻率ρ的范围可以为10Ω*cm～5000Ω*cm、10Ω*cm～3000Ω*cm、10Ω*cm～2000Ω*cm、10Ω*cm～1000Ω*cm、10Ω*cm～500Ω*cm、10Ω*cm～100Ω*cm、10Ω*cm～50Ω*cm、10Ω*cm～30Ω*cm、30Ω*cm～50Ω*cm、50Ω*cm～100Ω*cm、100Ω*cm～200Ω*cm、200Ω*cm～300Ω*cm、300Ω*cm～500Ω*cm、500Ω*cm～1000Ω*cm、1000Ω*cm～2000Ω*cm、2000Ω*cm～3000Ω*cm或3000Ω*cm～5000Ω*cm。
本发明中，所述正极活性物质在12MPa压力下的粉体电阻率可以采用已知的粉体电阻率测试方法进行测定。作为一个示例，采用四探针法测试正极活性物质在12MPa压力下的粉体电阻率，测试方法包括：将0.4g正极活性物质粉体加入样品模具(内径为11.28mm)中，通过压力机对粉体施加12MPa的压力，待压力稳定后，通过电阻率仪读取正极活性物质在12MPa压力下的粉体电阻率。
本发明所提供的正极材料中，单位体积的所述正极材料中包覆元素的含量Mv可以为400μg/cm 3～15000μg/cm 3、400μg/cm 3～12000μg/cm 3、800μg/cm 3～10000μg/cm 3、400μg/cm 3～600μg/cm 3、600μg/cm 3～800μg/cm 3、800μg/cm 3～1000μg/cm 3、1000μg/cm 3～2000μg/cm 3、2000μg/cm 3～4000μg/cm 3、4000μg/cm 3～6000μg/cm 3、6000μg/cm 3～8000μg/cm 3、8000μg/cm 3～10000μg/cm 3、10000μg/cm 3～12000μg/cm 3、或12000μg/cm 3～15000μg/cm 3，优选的，所述单位体积的所述正极材料中包覆元素的含量Mv为800μg/cm 3～10000μg/cm 3。本发明中，所述单位体积的所述正极材料中包覆元素的含量Mv在上述范围时，可以保证在不同体积粒径分布的体系下，二次颗粒的表面改性和正极材料极化问题得到兼容调整，有效改善高容量电池的产气问题、优化循环及倍率性能。
作为优选地，本发明所提供的正极材料中，所述正极材料的粉体电阻率ρ与单位体积的所述正极材料中包覆元素的含量Mv的比值满足：ρ/Mv≤1(Ω*cm 4/μg)、ρ/Mv≤0.8(Ω*cm 4/μg)、ρ/Mv≤0.6(Ω*cm 4/μg)、或ρ/Mv≤0.5(Ω*cm 4/μg)。计算上述比值时，所述正极材料的粉体电阻率的单位可以是Ω*cm，单位体积的所述正极材料中包覆元素的含量的单位可以是μg*cm -3。通常来说，ρ/Mv的比值越小，包覆元素含量越多，正极材料整体上极化更小，副反应更少，循环也更好。
本发明所提供的正极材料中，所述包覆元素至少选自Al、Ba、Zn、Ti、Zr、Mg、W、Y、Si、Sn、B、Co、P等中的两种以上。本发明中，所述基材表面可以设有氧化物包覆层，所述氧化物包覆层可以位于二次颗粒的表面，所述氧化物包覆层中的包覆元素可以在所述二次颗粒表面分布。在正极材料的基体表面的氧化物包覆层中，包覆元素可以以其氧化物的形式存在，所述氧化物包覆层中可以含有至少两种以上的上述包覆元素所形成的氧化物，从而可以提高包覆层在基材表面附着的稳定性，使包覆层兼具一定的导离子性和导电子性，减少包覆层对正极材料极化问题的影响，从而有效地避免高镍含量基体与电解液的直接接触，降低基体与电解液的副反应，避免循环过程中大量气体，同时保证电池的阻抗较低、循环和倍率性能优良。
本发明所提供的正极材料中，所述二次颗粒内部的、至少一部分一次颗粒的表面可以分 布有包覆元素，该部分包覆元素可以以其氧化物的形式存在；在相邻的所述一次颗粒之间晶界处也可以分布有包覆元素，该部分包覆元素可以以其氧化物的形式存在。二次颗粒是由若干个一次颗粒紧密堆积形成，在循环过程中，二次颗粒会发生体积的膨胀和收缩，导致二次颗粒内部一次颗粒之间的间距增大，暴露出大量未包覆的新鲜表面，因此存在与电解液发生副反应的风险。本发明中在二次颗粒表面设置包覆层的同时，在其内部至少一部分一次颗粒的表面或相邻一次颗粒之间晶界处进一步包覆，可以增强二次颗粒内部的致密度，提高内部一次颗粒之间的作用力，进一步优化循环过程中的产气问题。
本发明所提供的正极材料中，所述氧化物包覆层中所述包覆元素的含量可以占所述正极活性材料中总包覆元素质量的60wt％以上、70wt％以上、80wt％以上、90wt％以上，优选可以为80wt％～98wt％。本发明中，由于二次颗粒表面最先与电解液接触、相对面积更大，因此包覆元素在二次颗粒表面分布的质量占正极活性材料中总包覆元素质量的一定比例以上时，对高镍正极材料表面改性显著、对电池的产气抑制效果良好。
本发明所提供的正极材料中，所述正极材料为锂过渡金属氧化物，由于在制备过程中存在一定的元素含量偏析，因此所述正极材料的分子式中锂元素可能在一定程度上存在贫锂或者富锂的情况，锂元素的相对含量范围在0.95≤x≤1.05时，对所述正极材料的容量发挥影响不大，可选的，锂元素的相对含量可以为0.95≤x≤1、1≤x≤1.05。
本发明所提供的正极材料中，基材为镍含量较高的锂过渡金属氧化物，在所述基材的分子式中，0.50<y≤0.98，0≤z≤0.3，0≤k≤0.4，0≤p≤0.05。具体的，所述基材可以为LiNi 0.5Co 0.2Mn 0.3O 2、LiNi 0.5Co 0.25Mn 0.25O 2、LiNi 0.55Co 0.15Mn 0.3O 2、LiNi 0.55Co 0.1Mn 0.35O 2、LiNi 0.55Co 0.05Mn 0.4O 2、LiNi 0.6Co 0.2Mn 0.2O 2、LiNi 0.75Co 0.1Mn 0.15O 2、LiNi 0.8Co 0.1Mn 0.1O 2、LiNi 0.85Co 0.05Mn 0.1O 2、LiNi 0.88Co 0.05Mn 0.07O 2、LiNi 0.9Co 0.05Mn 0.05O 2，也可以为上述物质经过Me和/或A对进行部分取代改性后的材料，其中Me选自Zr、Zn、Cu、Cr、Mg、Fe、V、Ti、Sr、Sb、Y、W、Nb、Al中的一种或多种的组合，A选自F、Cl、Br中的一种或多种的组合。本发明中正极活性材料中选择镍含量较高的正极活性材料，由于Ni元素的相对含量越高、该材料的理论克容量越高，能够有效提高电池的体积能量密度；通过控制高镍正极活性材料的二次颗粒表面紧实度、单颗粒的抗压强度，能够有效解决高容量电池在循环过程的产气问题，提高电池的能量密度和使用寿命。作为优选的，本发明所提供的正极材料中，所述基材的结构式中，0.80≤y≤0.98，0≤z≤0.1，0≤k≤0.1，0≤p≤0.03。本发明中正极材料的基材Ni含量为0.80～0.98的锂镍钴锰氧化物时，表面的残锂含量更高，因此需要加大包覆量或者使用惰性更强的金属氧化物作为包覆层，而加大包覆层含量或者使用惰性更强的金属氧化物 对正极材料的阻抗影响更显著。通过协同调整掺杂和包覆工艺的元素及含量、控制正极材料的粉体电阻率，可以保证电池具有更高的体积和质量能量密度，具有良好的产气抑制效果，以及优良的循环、倍率性能。
本发明所提供的正极材料中，所述二次颗粒的Dv50可以为5μm～18μm，所述一次颗粒的粒径范围可以为0.1μm～1μm。所述Dv50通常指样品的体积累计分布百分数达到50％时对应的粒径。具体的，所述二次颗粒的Dv50可以为5μm～18μm、6μm～15μm、8μm～14μm、9μm～11μm、10μm～12μm、12μm～14μm、14μm～16μm、或16μm～18μm；所述一次颗粒的粒径范围可以为0.1μm～1μm、0.1μm～0.9μm、0.2μm～0.8μm、0.2μm～0.5μm。
本发明所提供的正极材料中，所述正极材料的比表面积为0.1m 2/g～0.8m 2/g。具体的，可以为0.1m 2/g～0.8m 2/g、0.1m 2/g～0.2m 2/g、0.2m 2/g～0.3m 2/g、0.3m 2/g～0.4m 2/g、0.4m 2/g～0.5m 2/g、0.5m 2/g～0.6m 2/g、0.6m 2/g～0.7m 2/g、或0.7m 2/g～0.8m 2/g。
本发明中，正极材料的平均粒径、BET比表面积设置在上述范围内，可以有效降低正极材料与电解液的接触面积，即使在高电压或强氧化性的作用下，电解液在正极活性物质表面发生副反应较少，有效抑制产气问题、降低产热量，电池的安全性能及循环性能得到有效改善；同时，充放电过程中锂离子在正极活性物质颗粒内嵌入与脱出的路径不会过长，进一步优化电池的动力学性能。
本发明所提供的正极材料中，所述正极材料表面的残锂中Li 2CO 3的含量(即所述基材表面的残锂中Li 2CO 3的质量相对于正极材料总质量的含量小于3000ppm，优选地，所述残锂中Li 2CO 3的含量小于2000ppm。所述正极材料表面的残锂中LiOH的含量(即所述正极材料表面的残锂中LiOH的质量相对于正极材料总质量的含量)小于5000ppm，优选地，所述残锂中LiOH的含量小于4000ppm。本发明的正极材料的基材为高镍含量的锂镍钴锰氧化物，表面残锂含量通常较高，在基材表面设置包覆层后可以有效降低表面残锂量，但是会导致正极材料的极化较大，选择表面残锂量在上述范围的正极材料，可以有效兼容产气问题和极化问题，获得容量较高、产气问题不显著、且循环和倍率性能优良的电池。
作为优选的，所述正极材料表面的残锂中Li 2CO 3的含量小于LiOH的含量。在正极材料表面，表面残锂(LiOH、Li 2O)容易与空气中的水分、CO 2等反应，反应产物为Li 2CO 3等。Li 2CO 3越高，说明反应程度越剧烈，相应制作出的电池的产气问题越严重。
本发明第二方面提供本发明第一方面所提供的正极材料的制备方法，包括：
提供基材；
在基材表面形成包覆层。
本发明所提供的正极材料的制备方法中，可以包括：提供基材。提供所述基材的方法对于本领域技术人员来说应该是已知的，例如，可以包括：将基材的原料混合、烧结，以提供基材。本领域技术人员可根据基材的元素组成，选择合适的基材的原料和配比。例如，所述基材的原料可以包括镍钴锰和/或铝的三元材料前驱体、锂源、M源、Me源、A源等，各原料之间的比例通常参照基材中各元素的比例进行配比。更具体的，所述三元材料前驱体可以是包括但不限于Ni 0.5Co 0.2Mn 0.3(OH) 2、Ni 0.5Co 0.25Mn 0.25(OH) 2、Ni 0.55Co 0.15Mn 0.3(OH) 2、Ni 0.55Co 0.1Mn 0.35(OH) 2、Ni 0.55Co 0.05Mn 0.4(OH) 2、Ni 0.6Co 0.2Mn 0.2(OH) 2、Ni 0.75Co 0.1Mn 0.15(OH) 2、Ni 0.8Co 0.1Mn 0.1(OH) 2、Ni 0.88Co 0.05Mn 0.07(OH) 2、0.9Ni 0.8Co 0.2(OH) 2·0.1Al 2(OH) 3、0.9Ni 0.9Co 0.05Mn 0.05(OH) 2·0.1Al 2(OH) 3，所述锂源可以是含锂的化合物，所述含锂化合物可以是包括但不限于LiOH·H 2O、LiOH、Li 2CO 3、Li 2O等中的一种或多种的组合，所述Me源通常可以是含Me元素的化合物，所述含Me元素的化合物可以是含有Zr、Zn、Cu、Cr、Mg、Fe、V、Ti、Sr、Sb、Y、W、Nb、Al中至少一种元素的氧化物、硝酸盐、碳酸盐中的一种或几种，所述A源可以是含A元素的化合物，所述含A元素的化合物可以是包括但不限于LiF、NaCl、NaBr等中的一种或多种的组合。再例如，所述烧结的条件可以是800℃、氧气浓度≥20％。
本发明所提供的正极材料的制备方法中，还可以包括：在基材表面形成包覆层。在基材表面形成包覆层的方法对于本领域技术人员来说应该是已知的，例如，可以包括：将基材在含包覆元素的化合物存在的条件下烧结，以在基材表面形成包覆层。本领域技术人员可根据包覆层的组成、基材的粉体电阻率等参数，选择合适的含包覆元素的化合物的种类、配比和烧结条件等。例如，所述含包覆元素的化合物可以是包括但不限于Al 2O 3、ZnO、ZrO 2、TiO 2、MgO、WO 3、Y 2O 3、Co 2O 3、Ba(NO 3) 2、Co 2O 3、P 2O 5、H 3BO 3等中的一种或多种的组合，再例如，所述包覆元素的使用量可以是基材质量的0.01wt％～0.5wt％，再例如，所述烧结的条件可以是200℃～700℃高温烧结。
本发明的第三方面提供一种电化学储能装置，包括本发明第一方面所提供的正极活性材料。
在本发明所提供的电化学储能装置中，需要说明的是，所述电化学储能装置可以为超级电容器、锂离子电池、锂金属电池或钠离子电池等。在本发明的实施例中，仅示出电化学储能装置为锂离子电池的实施例，但本发明不限于此。
在锂离子电池中，可以包括正极极片、负极极片、间隔于正极极片和负极极片之间的隔离膜、电解液，其中，所述正极极片包括本发明第一方面所提供的正极活性材料。制备所述 锂离子电池的方法对于本领域技术人员来说应该是已知的，例如，所述正极极片、隔离膜和负极极片各自都可以是层体，从而可以裁剪成目标尺寸后依次叠放，还可以卷绕至目标尺寸，以用于形成电芯，并可以进一步与电解液结合以形成锂离子电池。
在锂离子电池中，所述正极极片通常包含正极集流体和位于所述正极集流体上的正极材料层，所述正极材料层可以包括本发明第一方面所提供的正极活性材料、粘结剂、导电剂。本领域技术人员可选择合适的方法制备所述正极极片，例如，可以包括如下步骤：将正极活性材料、粘结剂、导电剂混合形成浆料后，涂布于正极集流体上。所述粘结剂通常包括含氟聚烯烃类粘结剂，相对于所述含氟聚烯烃类粘结剂来说，水通常是良溶剂，即所述含氟聚烯烃类粘结剂通常在水中具有良好的溶解性，例如，所述含氟聚烯烃类粘结剂可以是包括但不限于聚偏氟乙烯(PVDF)、偏氟乙烯共聚物等或它们的改性(例如，羧酸、丙烯酸、丙烯腈等改性)衍生物等。在所述正极材料层中，粘结剂的质量百分比含量可以是由于粘结剂本身的导电性较差，因此粘结剂的用量不能过高。优选地，正极活性物质层中粘结剂的质量百分含量小于等于2wt％，以获得较低的极片阻抗。所述正极极片的导电剂可以是本领域各种适用于锂离子(二次)电池的导电剂，例如，可以是包括但不限于乙炔黑、导电炭黑、碳纤维(VGCF)、碳纳米管(CNT)、科琴黑等中的一种或多种的组合。所述导电剂的重量可以占正极材料层总质量的1wt％～10wt％。更优选地，正极极片中导电剂与正极活性物质的重量比大于等于1.5:95.5。
在锂离子电池中，所述正极极片的正极集流体通常可以为层体，所述正极集流体通常是可以汇集电流的结构或零件，所述正极集流体可以是本领域各种适用于作为锂离子电池正极集流体的材料，例如，所述正极集流体可以是包括但不限于金属箔等，更具体可以是包括但不限于铜箔、铝箔等。
在锂离子电池中，所述负极极片通常包括负极集流体和位于负极集流体表面的负极活性物质层，所述负极活性物质层通常包括负极活性物质。所述负极活性物质可以是本领域各种适用于锂离子电池的负极活性物质的材料，例如，可以是包括但不限于石墨、软碳、硬碳、碳纤维、中间相碳微球、硅基材料、锡基材料、钛酸锂或其他能与锂形成合金的金属等中的一种或多种的组合。其中，所述石墨可选自人造石墨、天然石墨以及改性石墨中的一种或多种的组合；所述硅基材料可选自单质硅、硅氧化合物、硅碳复合物、硅合金中的一种或多种的组合；所述锡基材料可选自单质锡、锡氧化合物、锡合金中的一种或多种的组合。所述负极集流体通常是汇集电流的结构或零件，所述负极集流体可以是本领域各种适用于作为锂离子电池负极集流体的材料，例如，所述负极集流体可以是包括但不限于金属箔等，更具体可 以是包括但不限于铜箔等。
在锂离子电池中，所述隔离膜可以是本领域各种适用于锂离子电池隔离膜的材料，例如，可以是包括但不限于聚乙烯、聚丙烯、聚偏氟乙烯、芳纶、聚对苯二甲酸乙二醇酯、聚四氟乙烯、聚丙烯腈、聚酰亚胺，聚酰胺、聚酯和天然纤维等中的一种或多种的组合。
在锂离子电池中，所述电解液可以是本领域各种适用于锂离子电池的电解液，例如，所述电解液通常包括电解质和溶剂，所述电解质通常可以包括锂盐等，更具体的，所述锂盐可以是无机锂盐和/或有机锂盐等，具体可以是包括但不限于，所述锂盐可选自LiPF 6、LiBF 4、LiN(SO 2F) 2(简写为LiFSI)、LiN(CF 3SO 2) 2(简写为LiTFSI)、LiClO 4、LiAsF 6、LiB(C 2O 4) 2(简写为LiBOB)、LiBF 2C 2O 4(简写为LiDFOB)中的的一种或多种的组合。再例如，所述电解质的浓度可以为0.8mol/L～1.5mol/L之间。所述溶剂可以是本领域各种适用于锂离子电池的电解液的溶剂，所述电解液的溶剂通常为非水溶剂，优选可以为有机溶剂，具体可以是包括但不限于碳酸乙烯酯、碳酸丙烯酯、碳酸丁烯酯、碳酸戊烯酯、碳酸二甲酯、碳酸二乙酯、碳酸二丙酯、碳酸甲乙酯等或它们的卤代衍生物中的一种或多种的组合。
以下通过特定的具体实例说明本发明的实施方式，本领域技术人员可由本说明书所揭露的内容轻易地了解本发明的其他优点与功效。本发明还可以通过另外不同的具体实施方式加以实施或应用，本说明书中的各项细节也可以基于不同观点与应用，在没有背离本发明的精神下进行各种修饰或改变。
须知，下列实施例中未具体注明的工艺设备或装置均采用本领域内的常规设备或装置。
此外应理解，本发明中提到的一个或多个方法步骤并不排斥在所述组合步骤前后还可以存在其他方法步骤或在这些明确提到的步骤之间还可以插入其他方法步骤，除非另有说明；还应理解，本发明中提到的一个或多个设备/装置之间的组合连接关系并不排斥在所述组合设备/装置前后还可以存在其他设备/装置或在这些明确提到的两个设备/装置之间还可以插入其他设备/装置，除非另有说明。而且，除非另有说明，各方法步骤的编号仅为鉴别各方法步骤的便利工具，而非为限制各方法步骤的排列次序或限定本发明可实施的范围，其相对关系的改变或调整，在无实质变更技术内容的情况下，当亦视为本发明可实施的范畴。
实施例的电池均按照下述方法进行制备：
(1)正极材料的制备：
步骤1：制备基材前驱体；
步骤2：将步骤1所得的基材前驱体、含Li化合物、含Me化合物、含Y化合物置于混 料设备中进行混料，然后置于气氛炉中进行烧结，即获得正极材料的基材；
步骤3：将正极活性材料基体与一定含量的含包覆元素的化合物置于混料设备中进行混料，然后置于气氛炉中进行烧结，形成正极活性材料的包覆层，即为成品正极材料。
(2)正极极片的制备
步骤1：将上述正极材料、粘接剂聚偏氟乙烯、导电剂乙炔黑按照质量比98:1:1进行混合，加入N-甲基吡咯烷酮(NMP)，在真空搅拌机作用下搅拌均匀获得正极浆料；将正极浆料均匀涂覆于极片上，面密度为0.1mg/mm 2～0.3mg/mm 2；
步骤2：将涂覆后的极片经过100℃～130℃烘箱干燥、冷压、分切得到正极极片。
(2)负极极片的制备：
将负极活性材料石墨、增稠剂羧甲基纤维素钠、粘接剂丁苯橡胶、导电剂乙炔黑按照质量比97:1:1:1进行混合，加入去离子水，在真空搅拌机作用下获得负极浆料；将负极浆料均匀涂覆在厚度为8μm的铜箔上，0.05mg/mm 2～0.15mg/mm 2；将铜箔在室温晾干后转移至120℃烘箱干燥1h，然后经过冷压、分切得到负极片。
(3)电解液制备：
有机溶剂为含有碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)和碳酸二乙酯(DEC)的混合液，其中，EC、EMC和DEC的体积比为20:20:60。在含水量<10ppm的氩气气氛手套箱中，将充分干燥的LiPF 6锂盐溶解于有机溶剂中，混合均匀，获得电解液。其中，锂盐的浓度为1mol/L。
(4)隔离膜的制备：
选用12μm厚的聚丙烯隔离膜。
(5)电池的制备：
将正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正、负极片之间起到隔离的作用，再卷绕成方形的裸电芯后，装入铝塑膜，然后在80℃下烘烤除水后，注入相应的非水电解液、封口，经静置、热冷压、化成、夹具、分容等工序后，得到成品电池。
实施例1
在上文(1)正极材料的制备中，具体工艺为：
1)制备基材前驱体：
将硫酸镍、硫酸锰、硫酸钴按摩尔比8:1:1配置成浓度为1mol/L的溶液，利用氢氧化物共沉淀技术，制备得到较大粒径的锂镍过渡金属氧化物A的前驱体Ni 0.8Co 0.1Mn 0.1(OH) 2。制 备前躯体的过程中，通过控制反应时间、共沉淀时的pH值、氨浓度，实现对颗粒粒径的控制；
2)锂镍过渡金属氧化物A(多晶LiNi 0.8Co 0.1Mn 0.1O 2)的制备方法：
将大颗粒镍钴锰三元材料前驱体Ni 0.8Co 0.1Mn 0.1(OH) 2、含Li化合物LiOH·H 2O置于混料设备中进行混料，然后置于气氛炉中800℃进行烧结，冷却后通过机械研磨即为三元材料的基材；将正极活性材料基体与0.3wt％Al 2O 3的添加剂置于混料设备中进行混料，然后置于气氛炉中进行烧结450℃，形成正极活性材料的包覆层，即为成品材料。
实施例2～14
与实施例1的正极材料的制备方法基本相同，不同之处在于：前驱体中Ni、Co、Mn、Al元素的相对含量不同，制备出不同组分的基材；调节反应时间、共沉淀时的pH值、氨浓度，改变一次颗粒和二次颗粒的尺寸；同时，改变包覆层的物质种类、包覆量以及热处理温度，上述实施例中正极材料的具体特征参见表1，最终得到实施例2～14中的正极材料。
对比例1
对比例1的制备方法参照如上所述的实施例1制备方法，不同之处在于，对比例中的样品表面包覆V 2O 5。
对比例2
对比例2的制备方法参照如上所述的实施例17制备方法，不同之处在于，对比例中的样品表面包覆Fe 2O 3。
对比例3
对比例3的制备方法参照如上所述的实施例17制备方法，不同之处在于，对比例中的样品的包覆工艺中，加入Al 2O 3添加剂的烧结温度为600℃。
测试方法
(1)粉体电阻率测试
对各实施例和对比例所制备的正极材料进行粉体电阻率的测试，测试方法如下：
采用四探针法测试正极活性物质在12MPa压力下的粉体电阻率，测试方法包括：将0.4g正极活性物质粉体加入样品模具(内径为11.28mm)中，通过压力机对粉体施加12MPa的压 力，待压力稳定后，通过电阻率仪读取正极活性物质在12MPa压力下的粉体电阻率。实施例1～14和对比例1～3结果如表1所示。
(2)锂离子电池的45℃循环性能测试
在45℃的恒温环境下，在2.8V～4.2V下，按照1C充电至4.2V，然后在4.2V下恒压充电至电流≤0.05mA，静置5min，然后按照1C放电至2.8V，容量记为Dn(n＝0,1,2……)，重复前面过程，直至容量衰减到初始容量的80％，记录该锂离子电池的循环圈数。实施例1～14和对比例1～3结果如表2所示。
(3)锂离子电池的放电容量测试
在25℃的恒温环境下，在2.8V～4.2V下，按照1C充电至4.2V，然后在4.2V下恒压充电至电流≤0.05mA，静置5min，然后按照1C放电至2.8V，记录该锂离子电池的容量具体结果如表2所示。
表1
Figure PCTCN2019120585-appb-000001
Figure PCTCN2019120585-appb-000002
表2
Figure PCTCN2019120585-appb-000003
由上表可知：实施例1～14正极材料的锂离子电池的放电容量虽然与对比例1～3的放电容量基本持平，但是由于实施例1～14中正极材料的粉体电阻率明显低于对比例1～3，因此相应锂离子电池的循环性能明显的高于对比例1～3。包覆物质的种类、单位体积包覆元素的含量、以及包覆层的制备工艺影响着包覆层的导离子和导电子性，影响着正极材料的表面状态，对正极材料的粉体电阻率影响较大。由实施例1～5可以发现，调节单位体积下二次颗粒中包覆元素的含量，可以进一步优化正极材料的粉体电阻率，使得锂离子电池的循环性能进一步提升。与此同时，在正极材料表面包覆两种不同的包覆元素时，两种包覆物在正极材料 表面均匀分布，可以隔绝正极材料与电解液的副反应，同时保证正极材料的粉体电阻率较低，从而加强表面稳定性、使正极材料表面兼具良好的导离子性和导电子性，因此循环性能更好。
综上所述，本发明有效克服了现有技术中的种种缺点而具高度产业利用价值。
上述实施例仅例示性说明本发明的原理及其功效，而非用于限制本发明。任何熟悉此技术的人士皆可在不违背本发明的精神及范畴下，对上述实施例进行修饰或改变。因此，举凡所属技术领域中具有通常知识者在未脱离本发明所揭示的精神与技术思想下所完成的一切等效修饰或改变，仍应由本发明的权利要求所涵盖。

Claims (12)

  1. 一种正极材料，包括基材，所述基材包括由一次颗粒组成的二次颗粒，所述基材的分子式为Li xNi yCo zM kMe pO rA m，其中，0.95≤x≤1.05，0.50≤y≤0.98，0≤z≤0.3，0≤k≤0.4，0≤p≤0.05，1≤r≤2，0≤m≤2，m+r≤2，M选自Mn和/或Al，Me选自Zr、Zn、Cu、Cr、Mg、Fe、V、Ti、Sr、Sb、Y、W、Nb、Al中的一种或多种的组合，A选自F、Cl、Br中的一种或多种的组合；
    所述基材表面设有氧化物包覆层，所述氧化物包覆层包括包覆元素，所述包覆元素选自Al、Ba、Zn、Ti、Zr、Mg、W、Y、Si、Sn、B、Co、P中的一种或多种的组合；
    所述正极材料在12MPa压力下的粉体电阻率ρ为10Ω*cm～5000Ω*cm，优选为10Ω*cm～2000Ω*cm。
  2. 如权利要求1所述的正极材料，其特征在于，单位体积的所述正极材料中包覆元素的含量Mv为400μg/cm 3～15000μg/cm 3，优选为800μg/cm 3～10000μg/cm 3。
  3. 如权利要求1或2中任一项所述的正极材料，其特征在于，所述正极材料的粉体电阻率ρ与单位体积的所述正极材料中包覆元素的含量Mv满足：ρ/Mv≤1Ω*cm 4/μg，优选的，ρ/Mv≤0.5Ω*cm 4/μg。
  4. 如权利要求1所述的正极材料，其特征在于，所述包覆元素至少选自Al、Ba、Zn、Ti、W、Y、Si、Sn、B、Co、P中的两种以上。
  5. 如权利要求1所述的正极材料，其特征在于，所述二次颗粒内部的、至少一部分一次颗粒的表面分布有包覆元素；
    和/或，在相邻的所述一次颗粒之间晶界处分布有包覆元素。
  6. 如权利要求5所述的正极材料，其特征在于，所述氧化物包覆层中所述包覆元素的含量占所述正极活性材料中总包覆元素含量的60wt％以上，优选的，所述氧化物包覆层中所述包覆元素的含量占所述正极活性材料中总包覆元素含量的80wt％～98wt％。
  7. 如权利要求1所述的正极材料，其特征在于，在所述基材的分子式中，0.80≤y≤0.98，0≤z≤0.1，0≤k≤0.1，0≤p≤0.03。
  8. 如权利要求1所述的正极材料，其特征在于，所述二次颗粒的Dv50为5μm～18μm，所述一次颗粒的粒径范围为0.1μm～1μm；优选的，所述二次颗粒的Dv50为8μm～15μm，所述一次颗粒范围为0.2μm～0.8μm。
  9. 如权利要求1所述的正极材料，其特征在于，所述正极材料的比表面积为0.1m 2/g～0.8m 2/g。
  10. 如权利要求1～9任一权利要求所述的正极材料，其特征在于，所述正极材料表面的 残锂中Li 2CO 3的含量小于3000ppm，所述正极材料表面的残锂中LiOH的的含量小于5000ppm。
  11. 如权利要求10所述的正极材料，其特征在于，其特征在于，所述正极材料表面的残锂中Li 2CO 3的含量小于LiOH的含量。
  12. 一种电化学储能装置，包括如权利要求1～11中任一权利要求所述的正极材料。
PCT/CN2019/120585 2018-12-29 2019-11-25 一种正极材料及其制备方法和用途 Ceased WO2020134780A1 (zh)

Priority Applications (4)

Application Number Priority Date Filing Date Title
ES19901889T ES2940774T3 (es) 2018-12-29 2019-11-25 Material de electrodo positivo, su método de preparación y uso del mismo
EP19901889.6A EP3793008B1 (en) 2018-12-29 2019-11-25 Positive electrode material, preparation method therefor, and use thereof
US17/135,519 US11942636B2 (en) 2018-12-29 2020-12-28 Positive electrode material, preparation method and uses thereof
US18/435,387 US12176537B2 (en) 2018-12-29 2024-02-07 Positive electrode material, preparation method and uses thereof

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201811642372.9 2018-12-29
CN201811642372.9A CN111384377B (zh) 2018-12-29 2018-12-29 一种正极材料及其制备方法和用途

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US17/135,519 Continuation US11942636B2 (en) 2018-12-29 2020-12-28 Positive electrode material, preparation method and uses thereof

Publications (1)

Publication Number Publication Date
WO2020134780A1 true WO2020134780A1 (zh) 2020-07-02

Family

ID=71128312

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2019/120585 Ceased WO2020134780A1 (zh) 2018-12-29 2019-11-25 一种正极材料及其制备方法和用途

Country Status (6)

Country Link
US (2) US11942636B2 (zh)
EP (1) EP3793008B1 (zh)
CN (1) CN111384377B (zh)
ES (1) ES2940774T3 (zh)
PT (1) PT3793008T (zh)
WO (1) WO2020134780A1 (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2023542196A (ja) * 2020-11-10 2023-10-05 エルジー エナジー ソリューション リミテッド リチウム二次電池用正極活物質、その製造方法及びそれを含むリチウム二次電池

Families Citing this family (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111384377B (zh) * 2018-12-29 2021-09-17 宁德时代新能源科技股份有限公司 一种正极材料及其制备方法和用途
CN114068889A (zh) * 2020-08-06 2022-02-18 东莞新能安科技有限公司 正极材料、包含该正极材料的电化学装置和电子装置
CN116072816A (zh) * 2020-09-22 2023-05-05 宁德时代新能源科技股份有限公司 一种用于二次电池的正极极片、二次电池、电池模块、电池包和装置
CN114388723B (zh) * 2020-10-19 2024-03-22 上海科技大学 一种正极表面改性材料及其制备方法
CN112103492B (zh) * 2020-11-17 2021-03-23 湖南雅城新材料有限公司 一种改性锂离子电池三元正极材料及其制备方法与应用
CN112599734B (zh) * 2020-12-07 2022-02-08 宁德新能源科技有限公司 正极活性材料、电化学装置以及电子装置
CN113036117B (zh) * 2021-02-26 2022-12-09 蜂巢能源科技有限公司 一种四元正极材料及其制备方法
CN113130877B (zh) * 2021-06-18 2021-09-24 长沙理工大学 一种掺杂与浸渍包覆同步修饰的多晶正极材料及其固相制备方法与应用
CN113363497B (zh) * 2021-06-29 2023-06-30 惠州亿纬锂能股份有限公司 一种三元材料、制备方法及电池
CN113451560B (zh) * 2021-07-01 2022-08-26 清华大学深圳国际研究生院 正极活性材料及其制备方法、正极、三元锂离子电池
CN113659129A (zh) * 2021-08-18 2021-11-16 浙江帕瓦新能源股份有限公司 一种多元素掺杂的三元前驱体及其制备方法
CN114122379B (zh) * 2021-11-09 2023-09-05 远景动力技术(江苏)有限公司 正极材料及其制备方法和应用
CN114284470B (zh) * 2021-11-29 2023-07-14 蜂巢能源科技有限公司 正极材料、其制备方法、包括其的正极和锂离子电池
CN114551794B (zh) * 2021-12-17 2023-08-25 远景动力技术(江苏)有限公司 正极活性材料、正极及制备方法和锂离子电池
CN115832233B (zh) * 2022-01-14 2025-02-18 宁德时代新能源科技股份有限公司 一种正极活性材料、其制备方法及用电装置
CN114583150B (zh) * 2022-02-21 2023-07-21 远景动力技术(江苏)有限公司 正极活性材料及其应用
CN114361458B (zh) * 2022-03-10 2022-07-15 宁德时代新能源科技股份有限公司 正极材料及其制备方法、正极极片、二次电池、电池模块、电池包和用电装置
WO2023173403A1 (zh) * 2022-03-18 2023-09-21 宁德时代新能源科技股份有限公司 高镍三元正极材料及其制备方法、二次电池、电池模块、电池包和用电装置
CN114665081A (zh) * 2022-05-07 2022-06-24 湖南钠方新能源科技有限责任公司 一种正极材料及其制备方法、正极片和二次电池
CN114937762B (zh) * 2022-05-09 2024-02-09 北京理工大学 一种表面包覆ZnO、Li2ZnO2和Li3PO4的高镍NCM三元正极材料及其应用
CN115911356B (zh) * 2022-11-11 2026-04-17 宁波容百新能源科技股份有限公司 正极材料及其制备方法和应用
WO2024113299A1 (zh) * 2022-12-01 2024-06-06 宁德时代新能源科技股份有限公司 正极材料及其制备方法和包含其的二次电池和用电装置
CN115881913A (zh) * 2022-12-06 2023-03-31 天津巴莫科技有限责任公司 高镍正极材料、制备方法、正极片、电池和用电装置
CN115995615B (zh) * 2023-02-24 2026-03-10 欣旺达动力科技股份有限公司 一种二次电池及其制备方法
CN116454242A (zh) * 2023-04-28 2023-07-18 浙江华友钴业股份有限公司 一种多晶高镍三元正极材料及其制备方法与电池

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103296249A (zh) * 2013-06-19 2013-09-11 宁德新能源科技有限公司 掺杂改性锂镍钴锰、制备方法及锂离子电池
CN105118967A (zh) * 2015-09-23 2015-12-02 中信国安盟固利电源技术有限公司 一种金属氧化物包覆改性的掺杂三元正极材料及其制备方法
US20170155133A1 (en) * 2015-11-30 2017-06-01 Lg Chem, Ltd. Positive electrode active material for secondary battery and secondary battery including same
CN106865496A (zh) * 2017-04-19 2017-06-20 中南大学 铝掺杂纳米氧化锌包覆的镍钴铝酸锂正极材料及其制备方法
CN108269974A (zh) * 2017-01-01 2018-07-10 北京当升材料科技股份有限公司 一种多层次协同改性的锂电池正极材料及其制备方法
CN108777295A (zh) * 2018-05-29 2018-11-09 中航锂电（洛阳）有限公司 一种镍钴锰酸锂复合正极材料及其制备方法、锂离子电池

Family Cites Families (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ATE523906T1 (de) 2004-04-27 2011-09-15 Mitsubishi Chem Corp Schicht-lithium-nickel-mangan-kobalt- verbundoxidpulver für das material einer positivelektrode einer lithium-sekundärbatterie, herstellungsprozess dafür, positive elektrode einer lithium-sekundärbatterie daraus und lithium-sekundärbatterie
EP2466671A3 (en) * 2007-09-04 2012-08-22 Mitsubishi Chemical Corporation Lithium transition metal-based compound powder, method for manufacturing the same, spray-dried substance serving as firing precursor thereof, and lithium secondary battery positive electrode and lithium secondary battery using the same
JP4440339B2 (ja) 2008-05-15 2010-03-24 パナソニック株式会社 非水電解質二次電池用正極活物質、非水電解質二次電池用正極および非水電解質二次電池
JP5231171B2 (ja) 2008-10-30 2013-07-10 パナソニック株式会社 非水電解質二次電池用正極活物質およびその製造方法
KR101551355B1 (ko) * 2012-10-17 2015-09-09 주식회사 엘지화학 이차전지용 양극 활물질의 제조 방법 및 이를 사용해서 제조되는 양극 활물질
WO2015115699A1 (ko) * 2014-01-29 2015-08-06 주식회사 엘앤에프신소재 리튬 이차 전지용 양극 활물질, 이의 제조방법 및 이를 포함하는 리튬 이차 전지
KR20170090196A (ko) * 2016-01-28 2017-08-07 주식회사 엘지화학 전기화학 성능이 우수한 양극활물질 및 이를 포함하는 리튬 이차 전지
CN106711414A (zh) * 2016-12-16 2017-05-24 江南大学 一种锂离子电池811型三元正极改性材料及其制备方法
CN108206281B (zh) * 2016-12-20 2020-06-19 比亚迪股份有限公司 一种三元材料及其制备方法以及电池浆料和正极与锂电池
JP2020514971A (ja) * 2016-12-23 2020-05-21 ポスコＰｏｓｃｏ 二次電池用正極活物質製造方法および二次電池用活物質製造装置
JP6288338B1 (ja) * 2017-03-24 2018-03-07 住友大阪セメント株式会社 リチウムイオン二次電池用正極材料、リチウムイオン二次電池用正極、リチウムイオン二次電池
CN108878795B (zh) 2017-05-15 2021-02-02 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及电化学储能装置
CN107256966B (zh) 2017-05-17 2021-03-23 常州第六元素材料科技股份有限公司 一种锂离子电池正极极片及其制备方法
KR102698846B1 (ko) * 2017-11-22 2024-08-26 주식회사 엘지에너지솔루션 리튬 이차전지용 양극활물질 및 그 제조방법
JP6955696B2 (ja) * 2017-12-28 2021-10-27 Jnc株式会社 二次電池負極用組成物並びにこれを用いた二次電池用負極及び二次電池
CN110165205B (zh) 2018-02-11 2021-06-08 宁德时代新能源科技股份有限公司 正极材料及其制备方法、电池
CN111384377B (zh) * 2018-12-29 2021-09-17 宁德时代新能源科技股份有限公司 一种正极材料及其制备方法和用途

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103296249A (zh) * 2013-06-19 2013-09-11 宁德新能源科技有限公司 掺杂改性锂镍钴锰、制备方法及锂离子电池
CN105118967A (zh) * 2015-09-23 2015-12-02 中信国安盟固利电源技术有限公司 一种金属氧化物包覆改性的掺杂三元正极材料及其制备方法
US20170155133A1 (en) * 2015-11-30 2017-06-01 Lg Chem, Ltd. Positive electrode active material for secondary battery and secondary battery including same
CN108269974A (zh) * 2017-01-01 2018-07-10 北京当升材料科技股份有限公司 一种多层次协同改性的锂电池正极材料及其制备方法
CN106865496A (zh) * 2017-04-19 2017-06-20 中南大学 铝掺杂纳米氧化锌包覆的镍钴铝酸锂正极材料及其制备方法
CN108777295A (zh) * 2018-05-29 2018-11-09 中航锂电（洛阳）有限公司 一种镍钴锰酸锂复合正极材料及其制备方法、锂离子电池

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3793008A4 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2023542196A (ja) * 2020-11-10 2023-10-05 エルジー エナジー ソリューション リミテッド リチウム二次電池用正極活物質、その製造方法及びそれを含むリチウム二次電池
JP7652891B2 (ja) 2020-11-10 2025-03-27 エルジー エナジー ソリューション リミテッド リチウム二次電池用正極活物質、その製造方法及びそれを含むリチウム二次電池

Also Published As

Publication number Publication date
EP3793008A1 (en) 2021-03-17
PT3793008T (pt) 2023-03-17
US12176537B2 (en) 2024-12-24
CN111384377A (zh) 2020-07-07
ES2940774T3 (es) 2023-05-11
US20210119209A1 (en) 2021-04-22
US20240178385A1 (en) 2024-05-30
EP3793008B1 (en) 2023-02-22
EP3793008A4 (en) 2021-09-08
CN111384377B (zh) 2021-09-17
US11942636B2 (en) 2024-03-26

Similar Documents

Publication Publication Date Title
WO2020134780A1 (zh) 一种正极材料及其制备方法和用途
US12489112B2 (en) Positive electrode material and preparation method and usage thereof
CN112909238B (zh) 正极活性材料、正极极片及电化学储能装置
CN102420323B (zh) 锂二次电池的电极复合材料及其制备方法
WO2020134781A1 (zh) 一种高压实密度正极材料及电化学储能装置
WO2021108945A1 (zh) 一种用于二次电池的正极极片、二次电池、电池模块、电池包和装置
US11984583B2 (en) Positive electrode for all-solid secondary battery and all-solid secondary battery including the same
CN111384374B (zh) 负极活性材料、负极极片及电池
CN110233247A (zh) 正极活性材料、正极极片及电化学储能装置
CN103038928A (zh) 锂二次电池
CN108807959A (zh) 二次电池
CN114665065A (zh) 一种正极极片及其制备方法和应用
JP7556779B2 (ja) 負極活物質、負極、及び二次電池
CN109148890B (zh) 阴极极片及锂离子二次电池
CN111834662A (zh) 界面功能层及其制备方法和锂离子电池
CN105226271B (zh) 复合正极活性材料及锂离子二次电池
JP2026026371A (ja) 正極活物質およびリチウム二次電池
CN118553892A (zh) 改性富锂锰基材料、制备方法、正极材料、正极片和电池
WO2025077299A1 (zh) 负极极片、二次电池和用电设备
WO2020134774A1 (zh) 一种抗压的正极活性材料及电化学储能装置
JP2025540082A (ja) 全固体電池用負極及びこれを含む全固体電池
CN115304104A (zh) 锰系补锂添加剂及其制备方法和应用
US20240128500A1 (en) Solid electrolyte, method of preparing the same, positive electrode, and all-solid-state rechargeable battery
JP2024540133A (ja) 正極材、これを含む正極およびリチウム二次電池
CN115832615A (zh) 一种复合隔膜及其制备方法、二次电池和用电装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19901889

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2019901889

Country of ref document: EP

Effective date: 20201210

NENP Non-entry into the national phase

Ref country code: DE