WO2022207008A1 - 单晶型多元正极材料及其制备方法与应用 - Google Patents

单晶型多元正极材料及其制备方法与应用 Download PDF

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WO2022207008A1
WO2022207008A1 PCT/CN2022/091942 CN2022091942W WO2022207008A1 WO 2022207008 A1 WO2022207008 A1 WO 2022207008A1 CN 2022091942 W CN2022091942 W CN 2022091942W WO 2022207008 A1 WO2022207008 A1 WO 2022207008A1
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positive electrode
electrode material
single crystal
temperature
sintering
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PCT/CN2022/091942
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English (en)
French (fr)
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赵甜梦
宋顺林
刘亚飞
陈彦彬
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北京当升材料科技股份有限公司
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Priority to EP22779188.6A priority Critical patent/EP4159897A4/en
Priority to KR1020227045939A priority patent/KR20230098502A/ko
Priority to JP2022581592A priority patent/JP7398015B2/ja
Publication of WO2022207008A1 publication Critical patent/WO2022207008A1/zh
Priority to US18/091,977 priority patent/US20230202866A1/en

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    • C—CHEMISTRY; METALLURGY
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    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/40—Nickelates
    • C01G53/42—Nickelates containing alkali metals, e.g. LiNiO2
    • C01G53/44—Nickelates containing alkali metals, e.g. LiNiO2 containing manganese
    • C01G53/50—Nickelates containing alkali metals, e.g. LiNiO2 containing manganese of the type [MnO2]n-, e.g. Li(NixMn1-x)O2, Li(MyNixMn1-x-y)O2
    • C—CHEMISTRY; METALLURGY
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    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
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    • C30B1/00—Single-crystal growth directly from the solid state
    • C30B1/02—Single-crystal growth directly from the solid state by thermal treatment, e.g. strain annealing
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    • C30B1/00—Single-crystal growth directly from the solid state
    • C30B1/10—Single-crystal growth directly from the solid state by solid state reactions or multi-phase diffusion
    • H—ELECTRICITY
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    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
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    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
    • H—ELECTRICITY
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    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
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    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
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    • H01M4/36—Selection of substances as active materials, active masses, active liquids
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    • 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
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    • 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
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    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
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    • C01P2006/40—Electric properties
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    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
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    • 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 technical field of lithium ion batteries, in particular to a single crystal multi-element positive electrode material and a preparation method and application thereof.
  • Lithium-ion batteries have the advantages of high energy density, zero pollution, zero emissions and small size.
  • the positive electrode material plays a decisive role in the capacity, performance and cost of the battery.
  • the ternary material is due to its high energy density. , Long cycle life and high cost performance have been widely studied in recent years and developed rapidly.
  • the positive electrode material of ternary lithium-ion battery is mainly composed of Ni/Co/Mn.
  • the content of Ni is high and the capacity density of the material is high.
  • the increase of nickel content leads to the deterioration of the cycle life and safety of the material. change, the reaction between the positive electrode material and the electrolyte, etc.
  • Designing the material into a more stable single crystal structure can improve the cycling stability and thermal stability of the material.
  • the quality of the single crystal structure directly affects the electrochemical performance of the material.
  • the single crystal has a round morphology, uniform particle size, less agglomeration and adhesion. Fewer products can make the material denser in the process of making electrodes, and it is not easy to crack and fall off during the cycle, thereby improving the energy density and cycle stability of the material.
  • the synthesis process needs to be optimized.
  • the sintering process and doping and coating system By optimizing the sintering process and doping and coating system, lattice defects can be reduced, and the surface structure of the material can be stabilized, so as to ensure the high capacity of the material. At the same time, the stability of the material is improved and the battery performance is improved.
  • the purpose of the present invention is to provide a single crystal multi-element positive electrode in order to overcome the problems of uneven particle size, easy adhesion between particles, poor wettability of a single wafer and high agglomeration rate of the single-crystal multi-element positive electrode material in the prior art.
  • the single crystal multi-element cathode material has a round shape, uniform particle size, less agglomeration and less adhesion, and has the characteristics of high compaction density and good structural stability, and is used for lithium ion
  • the battery can significantly improve the energy density, rate performance, cycle stability and safety of lithium-ion batteries.
  • a first aspect of the present invention provides a single-crystal multi-element cathode material, characterized in that the cathode material satisfies the following conditions:
  • the agglomeration rate of the positive electrode material is less than or equal to 20%
  • 90% of the single crystal size of the DPS90 positive electrode material is smaller than DPS90 ; 50% of the single crystal size of the DPS50 positive electrode material is smaller than DPS50 ; 10% of the single crystal size of the DPS10 positive electrode material is smaller than DPS10 .
  • a second aspect of the present invention provides a method for preparing a single crystal multi-element cathode material, characterized in that the method comprises the following steps:
  • the second high temperature sintering is performed on the positive electrode material process product I to obtain the positive electrode material process product II;
  • a third aspect of the present invention provides a single crystal multi-element cathode material prepared by the above preparation method.
  • a fourth aspect of the present invention provides the application of the above single crystal multi-element cathode material in a lithium ion battery.
  • the single crystal multi-element cathode material provided by the present invention and its preparation method and application obtain the following beneficial effects:
  • the single crystal multi-element cathode material provided by the invention has the advantages of rounded morphology, uniform particle size, less agglomeration and less adhesion, and has the characteristics of high compaction density and good structural stability. Energy density, rate capability, and cycling stability and safety of lithium-ion batteries.
  • the mixture of the nickel cobalt manganese hydroxide precursor and the lithium salt is sintered at high temperature for a second time.
  • the secondary high-temperature sintering can make the fully lithiated positive electrode material process product easy to form single crystal, and the single crystal of the material is better.
  • lithium enters the material there is less residual lithium on the surface, the particles are not easy to stick together, and it is easy to form a single-crystal material with good independence, few internal defects and uniform size distribution.
  • water or carbon dioxide can be discharged during the first high-temperature sintering process, so that the weight and volume of the material can be reduced, and the second high-temperature sintering process can be reloaded into the reaction container, which can Inject more reactants to improve material yield and production efficiency.
  • the first high-temperature sintering process time of the mixture I is short and the reaction can be completed.
  • the second high-temperature sintering is easier to form a single crystal, and the single crystallization time can also be shortened. Therefore, without increasing the reaction time. , which can increase output and improve production efficiency.
  • the dopant D has a fluxing effect, and the introduction of the dopant D can reduce the temperature of the second high-temperature sintering, thereby saving energy and improving
  • the degree of single crystallization of the material makes the obtained single crystal material more rounded.
  • the high particle sphericity, uniform particle size distribution and low agglomeration rate make the battery pole piece made of the single crystal positive electrode material have a higher compaction density, and it is more stable during the battery operation process and is not easy to fall off, thereby improving the material cycle stability.
  • the cathode material process product II obtained by the second high temperature sintering is mixed with the coating agent, and the coated single crystal is obtained after the third high temperature sintering.
  • the coating agent can enter the crystal to a certain extent after high temperature sintering, forming a gradient on the surface of the material, thereby stabilizing the material structure; at the same time, the coating can react with the residual lithium on the surface at high temperature, reduce the residual lithium on the surface, and reduce side reactions ; High temperature sintering will also repair the internal defects of the single crystal, making the material structure more stable.
  • Fig. 1 is the SEM image of the positive electrode material finished product I prepared in the embodiment 1;
  • Fig. 2 is the SEM image of the positive electrode material finished product II obtained in Example 1;
  • Example 3 is a SEM image of the single crystal multi-element cathode material prepared in Example 1;
  • Fig. 4 is the SEM image of the positive electrode material finished product I prepared in the embodiment 12;
  • Fig. 5 is the SEM image of the positive electrode material finished product II prepared in Example 12;
  • Example 6 is a SEM image of the single-crystal multi-element cathode material prepared in Example 12;
  • FIG. 8 is a comparison diagram of 1.0C/1.0C@45°C cycle of Example 1 and Comparative Example 1 for 80 weeks.
  • a first aspect of the present invention provides a single-crystal multi-element positive electrode material, characterized in that the positive electrode material satisfies the following conditions:
  • the agglomeration rate of the positive electrode material is less than or equal to 20%
  • 90% of the single crystal size of the DPS90 positive electrode material is smaller than DPS90 ; 50% of the single crystal size of the DPS50 positive electrode material is smaller than DPS50 ; 10% of the single crystal size of the DPS10 positive electrode material is smaller than DPS10 .
  • the positive electrode material that satisfies the above conditions has a rounded morphology, uniform particle size, less agglomeration and less adhesion, and has the characteristics of high compaction density and good structural stability. Energy density, rate capability, and cycling stability and safety of lithium-ion batteries.
  • the positive electrode material is composed of single crystal particles.
  • D PS represents the size of a single crystal obtained from the scale in the SEM image of the positive electrode material
  • the D PS of a single particle is the average value of the longest diagonal line and the shortest diagonal line of the particle.
  • the D PS90 , D PS10 , D PS50 , B 90 and HPS of the positive electrode material particles are the statistical results obtained by randomly selecting 300 single crystal particles as samples in the SEM image.
  • the SEM test requires random sampling of the positive electrode material and random selection of the area.
  • the SEM image obtained by the test can represent the average level of the positive electrode material.
  • the long and short axis diagonal values of a single crystal can be obtained by any graphic analysis software or manual measurement, and the statistical results D PS90 , D PS10 , D PS50 , B 90 and HPS can be obtained by any statistical software.
  • the agglomeration rate refers to the proportion of four or more adhered single crystal particles in the total single crystal particles in the SEM image of the positive electrode material.
  • the agglomeration rate of the positive electrode material is ⁇ 15%, preferably ⁇ 10%; more preferably ⁇ 8%.
  • the average particle size D PS50 of the positive electrode material is 1-3 ⁇ m, preferably 1.2-2.8 ⁇ m, more preferably 1.5-2.5 ⁇ m.
  • the positive electrode material satisfies the following conditions: 0.1 ⁇ H PS ⁇ 0.5 ;
  • HPS is the statistical average of multiple crystal grains HPSn
  • HPSn is the calculation result of a single particle
  • HPSn 2(D PSLn -D PSSn )/(D PSLn +D PSSn )
  • D PSLn is the positive electrode material
  • D PSSn is the shortest diagonal length of a single crystal particle n of the positive electrode material measured by SEM.
  • the fact that the positive electrode material satisfies the above conditions indicates that the positive electrode material has the characteristics of uniform particle size, rounded shape, less agglomeration and less adhesion, thus making the positive electrode material have the advantages of high compaction density and good structural stability. For lithium-ion batteries, it can significantly improve the energy density, rate performance, cycle stability and safety of lithium-ion batteries.
  • the D50 of the positive electrode material is 2-5 ⁇ m, preferably 2-4 ⁇ m, more preferably 2.5-3.8 ⁇ m.
  • the D 50 of the positive electrode material is the result of the laser particle size analyzer test.
  • the positive electrode material has the composition shown in formula I:
  • A is selected from V, At least one of Ta, Cr, La, Ce, Er and Y;
  • D is selected from at least one of Mg, Sr, B, V, Al, Ca, Zn, Ba, Ra, Zr and Ti;
  • E is selected from At least one of Al, Nb, Co, Mn, Mo, W, Si, Mg, Ti, and Zr.
  • A is selected from La, At least one of Ce, Er and Y; D is selected from at least one of Sr, B, V, Al and Ca; E is selected from at least one of W, Si, Mg, Ti and Zr.
  • the compaction density PD of the single crystal multi-element cathode material is greater than or equal to 3.3 g/cm 3 , preferably 3.3-3.6 g/cm 3 .
  • the mixture of the precursor material and the lithium salt is subjected to two high-temperature sintering processes.
  • the temperature of the second high-temperature sintering is 20-200°C higher than that of the first high-temperature sintering to ensure that the positive electrode material process product I is obtained through the first high-temperature sintering.
  • a second aspect of the present invention provides a method for preparing a single crystal multi-element cathode material, characterized in that the method comprises the following steps:
  • the second high temperature sintering is performed on the positive electrode material process product I to obtain the positive electrode material process product II;
  • secondary high-temperature sintering is performed on the mixture of nickel-cobalt-manganese hydroxide precursor and lithium salt.
  • the secondary high-temperature sintering can make the fully lithiated positive electrode material process product easy to form single crystal, and the single crystal of the material is better.
  • lithium enters the material there is less residual lithium on the surface, the particles are not easy to stick together, and it is easy to form a single-crystal material with good independence, few internal defects and uniform size distribution.
  • the lithium source is selected from at least one of lithium carbonate, lithium nitrate, lithium hydroxide, lithium oxide and lithium acetate.
  • the added amount of the lithium source is added according to a stoichiometric ratio of 0.9 ⁇ [n(Li)]/[n(Ni)+n(Co)+n(Mn)] ⁇ 1.1.
  • the precursor and the lithium source when the added amount of the lithium source meets the above requirements, the precursor and the lithium source can be fully reacted, so that the prepared single-crystal multi-element cathode material has more excellent performance.
  • the added amount of the lithium source is 1 ⁇ [n(Li)]/[n(Ni)+n(Co)+n(Mn)] ⁇ 1.08 according to the stoichiometric ratio, preferably 1.02 ⁇ [n( Li)]/[n(Ni)+n(Co)+n(Mn)] ⁇ 1.06.
  • the dopant D has a fluxing effect during the second high-temperature sintering process, which can reduce the sintering temperature, save costs, and obtain a positive electrode material with better single crystallization.
  • the dopant D is selected from oxides, oxyhydroxides, hydroxides containing at least one element of Mg, Sr, B, V, Al, Ca, Zn, Ba, Ra, Zr and Ti , at least one of carbonate and oxalate.
  • the dopant D is selected from at least one of vanadium oxide, strontium hydroxide, strontium carbonate, boric acid, calcium oxide and barium oxide.
  • the addition amount of the dopant D is added according to a stoichiometric ratio of 0 ⁇ [n(D)]/[n(Ni)+n(Co)+n(Mn)] ⁇ 0.05.
  • the structure of the prepared positive electrode material can be stabilized.
  • the addition amount of the dopant D is added according to the stoichiometric ratio of 0.001 ⁇ [n(M)]/[n(Ni)+n(Co)+n(Mn)] ⁇ 0.03.
  • the conditions for the first high-temperature sintering include: a sintering temperature of 700-1000° C. and a sintering time of 2-10 h.
  • the first high-temperature sintering of the mixture I under the above conditions can ensure that the positive electrode material is fully lithiated, thereby making the prepared positive electrode material more excellent in overall performance.
  • the first high temperature sintering conditions include: sintering temperature is 750-900°C, preferably 800-900°C; sintering time is 3-10h, preferably 5-10h.
  • the D 50 of the positive electrode material Process I is 2-5 ⁇ m.
  • the positive electrode material process product I is a fully lithiated secondary particle ball composed of primary particles.
  • the positive electrode material thus prepared has a suitable size, and has a high compaction density, is structurally stable, and can maintain a high capacity.
  • the D 50 of the positive electrode material process product I is 2-4.5 ⁇ m, preferably 2-4 ⁇ m.
  • the conditions for the second high-temperature sintering include: a sintering temperature of 720-1200° C. and a sintering time of 5-20 h.
  • the second high-temperature sintering is performed on the positive electrode material process product I under the above-mentioned conditions, so that the obtained positive electrode material has a suitable single crystal size, and the particle size of the positive electrode material is uniform and the sphericity is good.
  • the second high-temperature sintering is performed after the positive electrode material process product I is crushed.
  • the conditions for the second high temperature sintering include: the sintering temperature is 850-1150°C, preferably 800-1100°C; the sintering time is 8-20h, preferably 10-18h.
  • the temperature of the second high temperature sintering is higher than the temperature of the first high temperature sintering, preferably 20-200°C higher; more preferably 30-100°C higher, further preferably 40-60°C higher.
  • the temperature of the second high-temperature sintering is controlled to be 20-200° C. higher than the temperature of the first high-temperature sintering, which can ensure that the positive electrode material process product I is obtained through the first high-temperature sintering, which is not only fully lithiated but also ensures that the secondary particle sphere If the first high-temperature sintering temperature is too low, sufficient lithiation cannot be achieved, and if the first high-temperature sintering temperature is too high, the positive electrode material process product I becomes a single crystal structure.
  • the D 50 of the positive electrode material process product II is 2-5 ⁇ m, preferably 2-4 ⁇ m.
  • the coating agent E is selected from oxides, oxyhydroxides, At least one of hydroxide, carbonate and oxalate. Specifically, the coating agent E is selected from at least one of magnesium oxide, silicon oxide, tungsten oxide and zirconium oxide.
  • the addition amount of the coating agent E is added according to a stoichiometric ratio of 0 ⁇ [n(E)]/[n(Ni)+n(Co)+n(Mn)] ⁇ 0.05.
  • the addition amount of the coating agent E is added according to the stoichiometric ratio of 0.001 ⁇ [n(E)]/[n(Ni)+n(Co)+n(Mn)] ⁇ 0.03.
  • the conditions for the third high-temperature sintering include: a sintering temperature of 500-900° C. and a sintering time of 3-10 h.
  • the third high-temperature sintering is performed on the mixture of the positive electrode material process product II and the coating agent E under the above conditions, which can modify the surface defects of the positive electrode material and stabilize the crystal surface structure.
  • the third high-temperature sintering is performed after crushing the positive electrode material process product II and mixing with the coating agent E.
  • the third high temperature sintering conditions include: sintering temperature is 600-900°C, preferably 700-800°C; sintering time is 4-10h, preferably 6-10h.
  • the nickel-cobalt-manganese hydroxide precursor can be a conventional precursor in the field, preferably, the nickel-cobalt-manganese hydroxide precursor is a precursor containing Ni, Co, Mn and dopant A hydroxide. Further, the nickel-cobalt-manganese hydroxide precursor is spherical or quasi-spherical single particles.
  • the nickel-cobalt-manganese hydroxide precursor is prepared according to the following steps:
  • the nickel salt, the cobalt salt and the manganese salt may be conventional nickel salts, cobalt salts and manganese salts in the art.
  • the nickel salt is selected from nickel sulfate and/or nickel chloride;
  • the cobalt salt is selected from cobalt sulfate and/or cobalt chloride;
  • the manganese salt is selected from manganese sulfate and/or manganese chloride.
  • the precipitating agent may be a conventional precipitating agent in the art, such as at least one of sodium hydroxide, potassium hydroxide, sodium carbonate and ammonium carbonate.
  • the complexing agent can be a conventional complexing agent in the art, such as ammonia water.
  • the concentration of the mixed salt is 1-3 mol/L; the concentration of the precipitant solution is 5-10 mol/L; the mass concentration of the ammonia water is 20-30 wt %.
  • the dopant A is selected from soluble salts and/or sols containing at least one element of V, Ta, Cr, La, Ce, Er and Y. Specifically, the dopant A is selected from one of erbium nitrate, yttrium sulfate and lanthanum nitrate.
  • the addition amount of the dopant A is added according to a stoichiometric ratio of 0 ⁇ [n(A)]/[n(Ni)+n(Co)+n(Mn)] ⁇ 0.05.
  • the addition amount of the dopant A is added according to a stoichiometric ratio of 0.001 ⁇ [n(A)]/[n(Ni)+n(Co)+n(Mn)] ⁇ 0.03.
  • the conditions for the continuous reaction include: the pH value is 11-13, the reaction temperature is 40-60°C, and the solution residence time is 6-30h.
  • the D 50 of the nickel-cobalt-manganese hydroxide precursor containing dopant A is 2-6 ⁇ m
  • the bulk density is 0.6-1 g/cm 3
  • the tap density is 1.2-1.6 g/cm 3 .
  • the D 50 of the nickel-cobalt-manganese hydroxide precursor containing dopant A is 2.5-5.5 ⁇ m
  • the bulk density is 0.6-0.9 g/cm 3
  • the tap density is 1.2-1.55 g/cm 3 .
  • a third aspect of the present invention provides a single crystal multi-element cathode material prepared by the above preparation method
  • the positive electrode material satisfies the following conditions:
  • the agglomeration rate of the positive electrode material is less than or equal to 20%
  • 90% of the single crystal size of the DPS90 positive electrode material is smaller than DPS90 ; 50% of the single crystal size of the DPS50 positive electrode material is smaller than DPS50 ; 10% of the single crystal size of the DPS10 positive electrode material is smaller than DPS10 .
  • the agglomeration rate of the positive electrode material is less than or equal to 15%, preferably less than or equal to 10%.
  • the average single crystal size D PS50 of the positive electrode material is 1-3 ⁇ m.
  • the average single crystal size D PS50 of the positive electrode material is 1.2-2.8 ⁇ m, preferably 1.5-2.5 ⁇ m.
  • the positive electrode material satisfies the following conditions: 0.1 ⁇ H PS ⁇ 0.5 ;
  • HPS is the statistical average of multiple crystal grains HPSn
  • HPSn is the calculation result of a single particle
  • HPSn 2(D PSLn -D PSSn )/(D PSLn +D PSSn )
  • D PSLn is the positive electrode material
  • D PSSn is the shortest diagonal length of a single crystal particle n of the positive electrode material measured by SEM.
  • the D50 of the positive electrode material is 2-5 ⁇ m, preferably 2-4 ⁇ m, more preferably 2.5-3.8 ⁇ m.
  • the positive electrode material has the composition shown in formula I:
  • A is selected from V, At least one of Ta, Cr, La, Ce, Er and Y;
  • D is selected from at least one of Mg, Sr, B, V, Al, Ca, Zn, Ba, Ra, Zr and Ti;
  • E is selected from At least one of Al, Nb, Co, Mn, Mo, W, Si, Mg, Ti, and Zr.
  • A is selected from La, At least one of Ce, Er and Y; D is selected from at least one of Sr, B, V, Al and Ca; E is selected from at least one of W, Si, Mg, Ti and Zr.
  • the compaction density PD of the single crystal multi-element cathode material is greater than or equal to 3.3 g/cm 3 , preferably 3.3-3.6 g/cm 3 .
  • a fourth aspect of the present invention provides an application of the above single crystal multi-element cathode material in a lithium ion battery.
  • the D 50 of the positive electrode material is the result of the laser particle size analyzer test
  • the single crystal size of the cathode material was obtained using the SEM ruler as the benchmark;
  • the compaction density of the positive electrode material is measured by a compaction density tester
  • the bulk density and tap density of the nickel-cobalt-manganese hydroxide precursor were measured by a tap density tester;
  • the cycle performance test is as follows: using an activated battery, with a current density of 1C in the voltage range of 3.0-4.3V, and at a temperature of 45°C, the high temperature capacity retention rate of the material is investigated for 80 cycles.
  • the performance evaluation of the fabricated button battery is defined as follows:
  • the cycle performance test is as follows: using an activated battery, with a current density of 1C in the voltage range of 3.0-4.3V, and at a temperature of 45°C, the high temperature capacity retention rate of the material is investigated for 80 cycles.
  • the electrical performance test parameters are tested by Shenzhen Xinwei CT-3008 battery test system.
  • Li 2 CO 3 and LiOH contents were obtained by potentiometric titration.
  • the raw materials used in the examples and comparative examples are all commercially available products.
  • a nickel-cobalt-manganese hydroxide precursor P1 with a D 50 of 3.3 ⁇ m containing a dopant La can be obtained , the precursor is spherical or quasi-spherical single particle with loose structure, the bulk density is 0.72g/cm 3 , and the tap density is 1.34g/cm 3 .
  • the mixture I was sintered at a first high temperature of 850° C. for 8 hours, cooled to room temperature naturally, crushed and sieved to obtain a positive electrode material process product I with a D 50 of 3.2 ⁇ m.
  • the cathode material process product I was sintered at a second high temperature at 900°C for 8 hours, cooled to room temperature naturally, crushed and sieved to obtain the cathode material process product II, D 50 was 3.2 ⁇ m, and the primary particles were independent of each other.
  • the temperature of the second high temperature sintering is 50°C higher than the temperature of the first high temperature sintering.
  • the mixture II is sintered at a third high temperature at 750° C. for 10 hours, naturally cooled to room temperature, crushed and sieved to obtain a single crystal multi-element cathode material A1.
  • Its composition is Li 1.05 (La 0.01 Ca 0.008 Ni 0.8 Co 0.1 Mn 0.1 )Mg 0.012 O 2 .
  • the performance parameters of the positive electrode material A1 are shown in Table 1.
  • Fig. 1 is the SEM image of the positive electrode material finished product I prepared in Example 1; it can be seen from Fig. 1 that the positive electrode material finished product I is an agglomerated compound.
  • FIG. 2 is a SEM image of the finished product II of the positive electrode material obtained in Example 1; it can be seen from FIG. 2 that the finished product II of the positive electrode material is a single crystal compound.
  • Figure 3 is the SEM image of the single crystal multi-element positive electrode material A1; it can be seen from Figure 3 that the positive electrode material A1 is a single crystal compound with a surface coating layer.
  • a nickel-cobalt-manganese hydroxide precursor P2 with a D 50 of 4 ⁇ m containing a dopant Ce can be obtained , the precursor is spherical or quasi-spherical single particle with loose structure, the bulk density is 0.73g/cm 3 , and the tap density is 1.35g/cm 3 .
  • the mixture I was sintered at a first high temperature of 840° C. for 4 hours, cooled to room temperature naturally, crushed and sieved to obtain a positive electrode material process product I with a D 50 of 3.1 ⁇ m.
  • the second high temperature sintering is performed on the cathode material process product I at 900° C. for 5 hours, naturally cooled to room temperature, crushed and sieved to obtain the cathode material process product II, D 50 is 3.0 ⁇ m, and the primary particles are independent of each other.
  • the temperature of the second high temperature sintering is 60°C higher than the temperature of the first high temperature sintering.
  • the mixture II is sintered at a third high temperature at 720° C. for 10 hours, naturally cooled to room temperature, crushed and sieved to obtain a single crystal multi-element cathode material A2.
  • Its composition is Li 1.05 (Ce 0.015 Sr 0.012 Ni 0.8 Co 0.1 Mn 0.1 )Si 0.01 O 2 .
  • the performance parameters of the positive electrode material A2 are shown in Table 1.
  • a nickel-cobalt-manganese hydroxide precursor P3 with a D 50 of 3.9 ⁇ m containing a dopant Er can be obtained , the precursor is spherical or quasi-spherical single particle with loose structure, the bulk density is 0.71g/cm 3 , and the tap density is 1.33g/cm 3 .
  • the mixture I was sintered at a first high temperature of 860° C. for 10 hours, naturally cooled to room temperature, crushed and sieved to obtain a positive electrode material process product I with a D 50 of 3.8 ⁇ m.
  • the cathode material process product I is sintered at a second high temperature at 900 ° C for 15h, naturally cooled to room temperature, crushed and sieved to obtain the cathode material process product II, D50 is 3.7 ⁇ m, and the primary particles are independent of each other.
  • the temperature of the second high temperature sintering is 40°C higher than the temperature of the first high temperature sintering.
  • the mixture II is sintered at a third high temperature at 780° C. for 6 hours, naturally cooled to room temperature, crushed and sieved to obtain a single crystal multi-element cathode material A3.
  • Its composition is: Li 1.04 (Er 0.015 B 0.009 Ni 0.8 Co 0.1 Mn 0.1 )W 0.01 O 2 .
  • the performance parameters of the positive electrode material A3 are shown in Table 1.
  • L of Cr 2 (SO 4 ) 3 solution, 8 mol/L NaOH solution was prepared as a precipitating agent, and 25 wt% ammonia water was directly used as a complexing agent.
  • a nickel-cobalt-manganese hydroxide precursor P4 with a D 50 of 4.1 ⁇ m containing dopant Cr can be obtained.
  • the precursor is spherical or quasi-spherical single particle with loose structure, the bulk density is 0.70g/cm 3 , and the tap density is 1.31g/cm 3 .
  • the mixture I was sintered at a first high temperature of 960° C. for 10 h, naturally cooled to room temperature, crushed and sieved to obtain a positive electrode material process product I with a D 50 of 3.4 ⁇ m.
  • the second high temperature sintering is carried out on the cathode material process product I at 980 ° C for 12 hours, and it is naturally cooled to room temperature, crushed and sieved to obtain the cathode material process product II.
  • the temperature of the second high temperature sintering is 20°C higher than the temperature of the first high temperature sintering.
  • the mixture II is sintered at a third high temperature at 820° C. for 9 hours, naturally cooled to room temperature, crushed and sieved to obtain a single crystal multi-element cathode material A4.
  • Its composition is: Li 1.05 (Cr 0.005 Al 0.01 Ni 0.5 Co 0.2 Mn 0.3 ) Zr 0.015 O 2 .
  • the performance parameters of the positive electrode material A4 are shown in Table 1.
  • a nickel-cobalt-manganese hydroxide precursor P5 with a D 50 of 4 ⁇ m can be obtained, and the precursor is spherical or similar Spherical single particle, loose structure, bulk density is 0.71g/cm 3 , tap density is 1.32g/cm 3 .
  • the cathode material process product I was sintered at a second high temperature at 800 ° C for 10 hours, cooled to room temperature naturally, crushed and sieved to obtain the cathode material process product II, D 50 was 4 ⁇ m, and the primary particles were independent of each other.
  • the temperature of the second high temperature sintering is 100°C higher than the temperature of the first high temperature sintering.
  • the mixture II is sintered at a third high temperature at 600° C. for 10 hours, naturally cooled to room temperature, crushed and sieved to obtain a single crystal multi-element cathode material A5.
  • Its composition is: Li 1.08 Y 0.012 Zn 0.014 Ni 0.95 Co 0.03 Mn 0.02 )Mo 0.008 O 2 .
  • the performance parameters of the positive electrode material A5 are shown in Table 1.
  • a nickel-cobalt-manganese hydroxide precursor P6 with a D 50 of 3.2 ⁇ m can be obtained, and the precursor is Spherical or quasi-spherical single particle, loose structure, bulk density is 0.71g/cm 3 , tap density is 1.33g/cm 3 .
  • the mixture I was sintered at a first high temperature of 850° C. for 8 hours, cooled to room temperature naturally, crushed and sieved to obtain a positive electrode material process product I with a D 50 of 3.1 ⁇ m.
  • the cathode material process product I was sintered at a second high temperature at 900 ° C for 8 hours, cooled to room temperature naturally, crushed and sieved to obtain the cathode material process product II, D 50 was 3.3 ⁇ m, and the primary particles were independent of each other.
  • the temperature of the second high temperature sintering is 50°C higher than the temperature of the first high temperature sintering.
  • the mixture II is sintered at a third high temperature at 750° C. for 10 hours, naturally cooled to room temperature, crushed and sieved to obtain a single crystal multi-element cathode material A6.
  • Its composition is Li 1.05 (Ni 0.8 Co 0.1 Mn 0.1 )O 2 .
  • the performance parameters of the positive electrode material A6 are shown in Table 1.
  • the single crystal multi-element cathode material was prepared according to the method of Example 1, except that the temperature of the second high-temperature sintering was kept unchanged, and the first high-temperature sintering temperature was adjusted so that the temperature of the second high-temperature sintering was higher than that of the first high-temperature sintering 130°C.
  • a single crystal multi-element cathode material A7 was prepared, and its performance parameters are shown in Table 1.
  • the single crystal multi-element cathode material was prepared according to the method of Example 1, except that the temperature of the second high-temperature sintering was kept unchanged, and the first high-temperature sintering temperature was adjusted so that the temperature of the second high-temperature sintering was higher than that of the first high-temperature sintering 180°C.
  • a single crystal multi-element cathode material A8 was prepared, and its performance parameters are shown in Table 1.
  • the single crystal multi-element cathode material was prepared according to the method of Example 1, except that the temperature of the second high-temperature sintering was kept unchanged, and the first high-temperature sintering temperature was adjusted so that the temperature of the second high-temperature sintering was higher than that of the first high-temperature sintering 10°C.
  • a single crystal multi-element cathode material A9 was prepared, and its performance parameters are shown in Table 1.
  • the single crystal multi-element cathode material was prepared according to the method of Example 1, except that the temperature of the second high-temperature sintering was kept unchanged, and the first high-temperature sintering temperature was adjusted so that the temperature of the second high-temperature sintering was higher than that of the first high-temperature sintering 400°C.
  • a single crystal multi-element cathode material A10 was prepared, and its performance parameters are shown in Table 1.
  • the single crystal multi-element cathode material was prepared according to the method of Example 1, except that the temperature of the second high-temperature sintering was kept unchanged, and the first high-temperature sintering temperature was adjusted so that the temperature of the second high-temperature sintering was lower than that of the first high-temperature sintering 50°C.
  • a single crystal multi-element cathode material A11 was prepared, and its performance parameters are shown in Table 1.
  • a nickel-cobalt-manganese hydroxide precursor P1 with a D 50 of 3.1 ⁇ m containing dopant La can be obtained , the precursor is spherical or quasi-spherical single particle with loose structure, the bulk density is 0.72g/cm 3 , and the tap density is 1.34g/cm 3 .
  • the mixture I was sintered at a first high temperature of 700° C. for 8 hours, cooled to room temperature naturally, crushed and sieved to obtain a positive electrode material process product I with a D 50 of 3.2 ⁇ m.
  • the cathode material process product I was sintered at a second high temperature at 900°C for 8 hours, cooled to room temperature naturally, crushed and sieved to obtain the cathode material process product II, D 50 was 3.2 ⁇ m, and the primary particles were independent of each other.
  • the temperature of the second high temperature sintering is 200°C higher than the temperature of the first high temperature sintering.
  • the mixture II is sintered at a third high temperature at 800° C. for 10 hours, naturally cooled to room temperature, crushed and sieved to obtain a single crystal multi-element cathode material A12.
  • Its composition is Li 1.1 (La 0.05 Ca 0.05 Ni 0.8 Co 0.1 Mn 0.1 )Mg 0.05 O 2 .
  • the performance parameters of the positive electrode material A12 are shown in Table 1.
  • FIG. 4 is the SEM image of the positive electrode material finished product I prepared in Example 12; it can be seen from Fig. 4 that the positive electrode material finished product I is an agglomerated compound.
  • FIG. 5 is the SEM image of the finished product II of the positive electrode material obtained in Example 12; it can be seen from FIG. 5 that the finished product II of the positive electrode material is a single crystal compound.
  • FIG. 6 is a SEM image of the single-crystal multi-element cathode material A12; it can be seen from FIG. 6 that the cathode material A12 is a single-crystal compound with a surface coating layer.
  • the nickel-cobalt-manganese hydroxide precursor was prepared according to the method of Example 1.
  • the single-crystal multi-element cathode material was prepared according to the method of Example 1, except that step S2 was not performed, and the mixture I was directly subjected to the second high-temperature sintering.
  • the single-crystal multi-element cathode material D1 was prepared. Its composition is: Li 1.05 (La 0.01 Ca 0.008 Ni 0.8 Co 0.1 Mn 0.1 )Mg 0.012 O 2 .
  • the performance parameters of the positive electrode material D1 are shown in Table 1.
  • FIG. 7 is the SEM image of the positive electrode material D1. It can be seen from FIG. 7 that the size of the material is uneven, the agglomeration rate is high, and the single crystallization is poor.
  • the precursor PD2 of nickel-cobalt-manganese hydroxide with a D 50 of 4.5 ⁇ m can be obtained, and the precursor is spherical or similar Spherical single particle, loose structure, bulk density is 0.72g/cm 3 , tap density is 1.34g/cm 3 .
  • the mixture I is sintered at a second high temperature at 980° C. for 12 hours, naturally cooled to room temperature, crushed and sieved to obtain a positive electrode material process product II with a D 50 of 3.4 ⁇ m.
  • the mixture II is sintered at a third high temperature at 820° C. for 9 hours, naturally cooled to room temperature, crushed and sieved to obtain a single crystal multi-element cathode material D2.
  • Its composition is: Li 1.06 (Cr 0.01 Al 0.01 Ni 0.5 Co 0.2 Mn 0.3 ) Zr 0.01 O 2 .
  • the performance parameters of the cathode material D2 are shown in Table 1.
  • Y(NO 3 ) 3 solution 8 mol/L NaOH solution was prepared as a precipitating agent, and 25 wt% ammonia water was directly used as a complexing agent.
  • the precursor PD3 of nickel-cobalt-manganese hydroxide with a D 50 of 3.1 ⁇ m can be obtained.
  • the precursor is spherical or similar Spherical single particle, loose structure, bulk density is 0.72g/cm 3 , tap density is 1.34 g /cm 3 .
  • the mixture I was sintered at a second high temperature at 800° C. for 10 hours, cooled to room temperature naturally, crushed and sieved to obtain a positive electrode material process product II with a D 50 of 3.0 ⁇ m.
  • the mixture II is sintered at a third high temperature at 600° C. for 7 hours, naturally cooled to room temperature, crushed and sieved to obtain a single crystal multi-element cathode material D3.
  • Its composition is: Li 1.06 (Y 0.01 Zn 0.01 Ni 0.95 Co 0.03 Mn 0.02 ) Mo 0.01 O 2 .
  • the performance parameters of the cathode material D3 are shown in Table 1.
  • a button-type battery is prepared, and the specific preparation method is as follows:
  • the composite nickel-cobalt-manganese multi-element cathode active material for non-aqueous electrolyte secondary battery, acetylene black and polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 95:3:2, coated on aluminum foil and dried.
  • the positive pole piece with a diameter of 12 mm and a thickness of 120 ⁇ m was punched and formed into a positive pole piece with a pressure of 100 MPa, and then the positive pole piece was placed in a vacuum drying box for drying at 120° C. for 12 hours.
  • the negative electrode uses a Li metal sheet with a diameter of 17 mm and a thickness of 1 mm; the separator uses a polyethylene porous membrane with a thickness of 25 ⁇ m; the electrolyte uses 1 mol/L LiPF 6 , ethylene carbonate (EC) and diethyl carbonate (DEC). Equal amount of mixture.
  • the positive electrode, separator, negative electrode and electrolyte were assembled into a 2025 type button battery in an Ar gas glove box with water content and oxygen content less than 5 ppm, and the battery at this time was regarded as an unactivated battery.
  • Figure 8 is a comparison diagram of Example 1 and Comparative Example 1 at 1C/1C@45°C for 80 cycles. It can be seen from Figure 8 that the capacity of Example 1 is slightly higher than that of Comparative Example 1, and the cycle retention rate of Example 1 It is significantly higher than that of Comparative Example 1, and as the cycle progresses, the capacity of Example 1 decreases steadily, while the decreasing trend of the capacity of Comparative Example 1 becomes faster and faster.
  • Embodiments 1-3 adopt the conditions within the preferred range of the present invention.
  • the prepared positive electrode materials have moderate D PS , B 90 and H PS are small, indicating that the single wafer is moist, the sphericity is good, and the size is uniform, The agglomeration rate is also lower, and the capacity is higher with better circulation.
  • Examples 7-12 did not adopt the conditions within the preferred range of the present invention.
  • the single crystallization and performance of the prepared positive electrode materials were slightly worse than those of Examples 1-3, but better than those of Comparative Examples 1-3.

Abstract

一种单晶型多元正极材料及其制备方法与应用。该正极材料满足以下条件：正极材料通过SEM测得的单晶尺寸D PS90、D PS10与D PS50满足以下关系：0.1≤B 90＝(D PS90-D PS10)/D PS50≤1.5；正极材料的团聚率≤20％；其中，D PS90正极材料的单晶尺寸90％小于D PS90；DPS50正极材料的单晶尺寸50％小于D PS50；D PS10正极材料的单晶尺寸10％小于D PS10。该单晶型多元正极材料的形貌圆润、颗粒尺寸均一、团聚少、粘连少，压实密度高、结构稳定性好，将其用于锂离子电池，能够提高锂离子电池的能量密度、倍率性能以及循环稳定性和安全性。

Description

单晶型多元正极材料及其制备方法与应用
相关申请的交叉引用
本申请要求2021年12月24日提交的中国专利申请202111595596.0的权益，该申请的内容通过引用被合并于本文。
技术领域
本发明涉及锂离子电池技术领域，具体涉及一种单晶型多元正极材料及其制备方法与应用。
背景技术
能源及环境问题一直是当今社会的热点。随着我国新能源汽车市场的扩大，动力锂离子电池需求大幅上升，而手机、相机、电动车、电动工具等行业的快速发展，也使锂离子电池的需求量不断增长。因此，锂离子电池行业具有良好的发展前景。
锂离子电池具有能量密度高、零污染、零排放和体积小等优点，正极材料作为锂离子电池的主要组成部分，对电池的容量、性能及成本起决定性作用，三元材料因其能量密度高、循环寿命长、性价比高近年来被广泛研究，发展迅速。
三元锂离子电池正极材料主要由Ni/Co/Mn组成，Ni含量高，材料容量密度高，但镍含量提升导致材料的循环寿命及安全性变差，主要原因有锂镍混排、多重相变、正极材料与电解液反应等。将材料设计成更稳定的单晶结构可以提升材料的循环稳定性和热稳定性，单晶结构的好坏直接影响材料的电化学性能，单晶形貌圆润、颗粒尺寸均一、团聚少、粘连少的产品能够使材料在制作电极过程中压实密度更大，且循环过程中不易发生碎裂及脱落，从而提升材料的能量密度和循环稳定性。
为了得到结构稳定的三元单晶型正极材料，需要对合成过程进行优化，通过优化烧结过程及掺杂、包覆体系可以减少晶格缺陷，并稳定材料表面结构，从而在保证材料高容量的同时，提高材料的稳定性，提升电池性能。
发明内容
本发明的目的是为了克服现有技术存在的单晶型多元正极材料的颗粒尺寸不均一、颗粒之间易粘连、单晶圆润度差及团聚率高的问题，提供一种单晶型多元正极材料及其制备方法与应用，该单晶型多元正极材料的形貌圆润、颗粒尺寸均一、团聚少、粘连少，并且具有压实密度高、结构稳定性好的特点，将其用于锂离子电池，能够显著提高锂离子电池的能量密度、倍率性能以及循环稳定性和安全性。
为了实现上述目的，本发明第一方面提供一种单晶型多元正极材料，其特征在于，所述正极材料满足以下条件：
(1)正极材料通过SEM测得的单晶尺寸D PS90、D PS10与D PS50满足以下关系：0.1≤B 90＝(D PS90-D PS10)/D PS50≤1.5；
(2)所述正极材料的团聚率≤20％；
其中，D PS90正极材料的单晶尺寸90％小于D PS90；D PS50正极材料的单晶尺寸50％小于D PS50；D PS10正极材料的单晶尺寸10％小于D PS10。
本发明第二方面提供一种单晶型多元正极材料的制备方法，其特征在于，所述方法包括以下步骤：
S1、将镍钴锰氢氧化物前驱体、锂源、可选地掺杂剂D进行混合，得到混合物I；
S2、在氧气或空气气氛中，对所述混合物I进行第一高温烧结，得到正极材料过程品I；
S3、在氧气或空气气氛中，对所述正极材料过程品I进行第二高温烧结，得到正极材料过程品II；
S4、将所述正极材料过程品II与可选地包覆剂E进行混合，得到混合物II；
S5、在氧气或空气气氛中，对所述混合物II进行第三高温烧结，得到所述单晶型多元正极材料。
本发明第三方面提供由上述制备方法制得的单晶型多元正极材料。
本发明第四方面提供上述单晶型多元正极材料在锂离子电池中的应用。
通过上述技术方案，本发明提供的单晶型多元正极材料及其制备方法与应用获得以下有益的效果：
本发明提供的单晶型多元正极材料的形貌圆润、颗粒尺寸均一、团聚少、粘连少，并且具有压实密度高、结构稳定性好的特点，将其用于锂离子电池，能够显著提高锂离子电池的能量密度、倍率性能以及循环稳定性和安全性。
本发明提供的单晶型多元正极材料的制备方法中，对镍钴锰氢氧化物前驱体与锂盐的混合物进行二次高温烧结。二次高温烧结能够使得充分锂化的正极材料过程品易于形成单晶，材料单晶化更好。且经第一高温烧结后锂进入到材料内部，表面残锂更少，颗粒之间不易粘连，容易形成独立性好，内部缺陷少，大小分布均匀的单晶化材料。
进一步地，本发明提供的单晶型多元正极材料的制备方法中，第一高温烧结过程中能够排出水或二氧化碳，使材料重量及体积减小，第二高温烧结重新装入反应容器，能够装入更多的反应物，提升材料的产量及生产效率。且混合物I第一高温烧结过程时间较短既能反应完全，经过第一高温烧结后，第二高温烧结形成单晶较容易，也可以缩短单晶化时间，因此在不增加反应时间的前提下，能够提升产量，并提升生产效率。
进一步地，本发明提供的单晶型多元正极材料的制备方法中，掺杂剂D具有助熔做用，掺杂剂D的引入能够降低第二高温烧结的温度，从而节省能源，并能够提升材料的单晶化程度，使得到的单晶材料更加圆润。颗粒球形度高，颗粒尺寸分布均匀，团聚率低，使该单晶正极材料制作的电池极片压实密度更大，且在电池工作过程中更加稳定，不易脱落，从而提升材料循环稳定性。
进一步地，本发明提供的单晶型多元正极材料的制备方法中，将第二高温烧结得到的正极材料过程品II与包覆剂进行混合，经过第三次高温烧结，得到包覆型单晶正极材料，包覆剂经过高温烧结，能够一定程度的进入到晶体内部，在材料表面形成梯度，从而稳定材料结构；同时包覆物高温可以与表面残锂反应，降低表面残锂，减少副反应；高温烧结也会修复单晶内部缺陷，使得材料结构更加稳定。
附图说明
图1为实施例1中制得的正极材料过成品I的SEM图；
图2为实施例1中制得的正极材料过成品II的SEM图；
图3为实施例1中制得的单晶型多元正极材料的SEM图；
图4为实施例12中制得的正极材料过成品I的SEM图；
图5为实施例12中制得的正极材料过成品II的SEM图；
图6为实施例12中制得的单晶型多元正极材料的SEM图；
图7为对比例1中制得的单晶型多元正极材料的SEM图；
图8为实施例1与对比例1的1.0C/1.0C@45℃循环80周的对比图。
具体实施方式
在本文中所披露的范围的端点和任何值都不限于该精确的范围或值，这些范围或值应当理解为包含接近这些范围或值的值。对于数值范围来说，各个范围的端点值之间、各个范围的端点值和单独的点值之间，以及单独的点值之间可以彼此组合而得到一个或多个新的数值范围，这些数值范围应被视为在本文中具体公开。
本发明第一方面提供一种单晶型多元正极材料，其特征在于，所述正极材料满足以下条件：
(1)正极材料通过SEM测得的单晶尺寸D PS90、D PS10与D PS50满足以下关系：0.1≤B 90＝(D PS90-D PS10)/D PS50≤1.5；
(2)所述正极材料的团聚率≤20％；
其中，D PS90正极材料的单晶尺寸90％小于D PS90；D PS50正极材料的单晶尺寸50％小于D PS50；D PS10正极材料的单晶尺寸10％小于D PS10。
本发明中，满足上述条件的正极材料的形貌圆润、颗粒尺寸均一、团聚少、粘连少，并且具有压实密度高、结构稳定性好的特点，将其用于锂离子电池，能够显著提高锂离子电池的能量密度、倍率性能以及循环稳定性和安全性。
本发明中，所述正极材料由单晶颗粒组成。
本发明中，D PS表示由正极材料的SEM图中标尺为基准得到的单晶尺寸，单一颗粒的D PS为此颗粒的最长对角线与最短对角线的平均值。正极材料颗粒的D PS90、D PS10、D PS50、B 90及H PS为SEM图中随机选取300颗单晶颗粒作为样本所得到的统计结果。SEM测试要求正极材料随机取样，随机选取区域，测试得到的SEM图能够代表正极材料的平均水平。单晶的长短轴对角线数值可以由任意图形分析软件或人工测量获得，数据统计结果D PS90、D PS10、D PS50、B 90及H PS可以由任意统计软件获得。
本发明中，所述团聚率是指正极材料的SEM图中四个及以上粘连的单晶颗粒占总单晶颗粒的比例。
进一步地，正极材料通过SEM测得的单晶尺寸D PS90、D PS10与D PS50满足以下关系：0.1≤B 90＝(D PS90-D PS10)/D PS50≤1.3；优选地，0.1≤B 90＝(D PS90-D PS10)/D PS50≤1.1；更优选为0.5≤B 90＝(D PS90-D PS10)/D PS50≤1.3；进一步优选为0.7≤B 90＝(D PS90-D PS10)/D PS50≤1.1。
进一步地，所述正极材料的团聚率≤15％，优选≤10％；更优选≤8％。
根据本发明，所述正极材料的平均单晶尺寸(particle size)D PS50为1-3μm，优选为1.2-2.8μm，更优选为1.5-2.5μm。
根据本发明，所述正极材料满足如下条件：0.1≤H PS≤0.5；
其中，H PS为多个晶粒颗粒H PSn的统计平均数，H PSn为单个颗粒计算结果，H PSn＝2(D PSLn-D PSSn)/(D PSLn+D PSSn)，D PSLn为正极材料通过SEM测得的单个晶粒颗粒n的最长对角线长度，D PSSn为正极材料通过SEM测得的单个晶粒颗粒n的最短对角线长度。
本发明中，正极材料满足上述条件表明正极材料具有颗粒尺寸均一、形貌 圆润、团聚少、粘连少的特点，由此使得正极材料具有压实密度高、结构稳定性好的优点，将其用于锂离子电池，能够显著提高锂离子电池的能量密度、倍率性能以及循环稳定性和安全性。
进一步地，0.1≤H PS≤0.4，更进一步地，0.1≤H PS≤0.3。
根据本发明，所述正极材料的D 50为2-5μm，优选为2-4μm，更优选为2.5-3.8μm。
本发明中，所述正极材料的D 50为激光粒度仪测试的结果。
根据本发明，所述正极材料具有式I所示的组成：
Li 1+a(A mD nNi xMn yCo z)E iO 2式I
其中，-0.1≤a≤0.1，0≤m≤0.05，0≤n≤0.05，0.5≤x＜1，0＜y＜0.5，0≤z＜0.5，0≤i≤0.05；A选自V、Ta、Cr、La、Ce、Er和Y中的至少一种；D选自Mg、Sr、B、V、Al、Ca、Zn、Ba、Ra、Zr和Ti中的至少一种；E选自Al、Nb、Co、Mn、Mo、W、Si、Mg、Ti和Zr中的至少一种。
进一步地，0≤a≤0.08，0.001≤m≤0.03，0.001≤n≤0.03，0.7≤x＜0.9，0.1＜y＜0.3，0.1≤z＜0.3，0.001≤i≤0.03；A选自La、Ce、Er和Y中的至少一种；D选自Sr、B、V、Al和Ca中的至少一种；E选自W、Si、Mg、Ti和Zr中的至少一种。
本发明中，所述单晶型多元正极材料的压实密度PD≥3.3g/cm 3，优选为3.3-3.6g/cm 3。
本发明中单晶型多元正极材料的制备方法中，前驱体材料和锂盐的混合物要经过两次高温烧结过程。
所述第二高温烧结的温度比第一高温烧结的温度高20-200℃，确保经第一高温烧结得到正极材料过程品I，既充分锂化又保证二次颗粒球的状态。
本发明第二方面提供一种单晶型多元正极材料的制备方法，其特征在于，所述方法包括以下步骤：
S1、将镍钴锰氢氧化物前驱体、锂源、可选地掺杂剂D进行混合，得到混合物I；
S2、在氧气或空气气氛中，对所述混合物I进行第一高温烧结，得到正极材料过程品I；
S3、在氧气或空气气氛中，对所述正极材料过程品I进行第二高温烧结，得到正极材料过程品II；
S4、将所述正极材料过程品II与可选地包覆剂E进行混合，得到混合物II；
S5、在氧气或空气气氛中，对所述混合物II进行第三高温烧结，得到所述单晶型多元正极材料。
本发明中，对镍钴锰氢氧化物前驱体与锂盐的混合物进行二次高温烧结。二次高温烧结能够使得充分锂化的正极材料过程品易于形成单晶，材料单晶化更好。且经第一高温烧结后锂进入到材料内部，表面残锂更少，颗粒之间不易粘连，容易形成独立性好，内部缺陷少，大小分布均匀的单晶化材料。
根据本发明，步骤S1中，所述锂源选自碳酸锂、硝酸锂、氢氧化锂、氧化锂和醋酸锂中的至少一种。
根据本发明，所述锂源的加入量按照化学计量比为0.9≤[n(Li)]/[n(Ni)+n(Co)+n(Mn)]≤1.1添加。
本发明中，所述锂源的加入量满足上述要求时，能够使得前驱体与锂源充分反应，进而使得制得的单晶型多元正极材料具有更为优异的性能。
进一步地，所述锂源的加入量按照化学计量比为1≤[n(Li)]/[n(Ni)+n(Co)+n(Mn)]≤1.08，优选为1.02≤[n(Li)]/[n(Ni)+n(Co)+n(Mn)]≤1.06。
本发明中，所述掺杂剂D在第二高温烧结过程中具有助熔作用，能够降低烧结温度，节约成本，并得到单晶化较好的正极材料。
根据本发明，所述掺杂剂D选自含有Mg、Sr、B、V、Al、Ca、Zn、Ba、Ra、Zr和Ti中至少一种元素的氧化物、羟基氧化物、氢氧化物、碳酸盐和草酸盐中的至少一种。具体地，所述掺杂剂D选自氧化钒、氢氧化锶、碳酸锶、硼酸、氧化钙和氧化钡中的至少一种。
根据本发明，所述掺杂剂D的加入量按照化学计量比为0≤[n(D)]/[n(Ni)+n(Co)+n(Mn)]≤0.05添加。
本发明中，所述掺杂剂D的用量满足上述范围时，能够使得制得的正极材料结构稳定。
进一步地，所述掺杂剂D的加入量按照化学计量比为0.001≤[n(M)]/[n(Ni)+n(Co)+n(Mn)]≤0.03添加。
根据本发明，步骤S2中，所述第一高温烧结的条件包括：烧结温度为700-1000℃，烧结时间为2-10h。
本发明中，在上述条件下对混合物I进行第一高温烧结，能够确保正极材料充分锂化，进而使得制得的正极材料的综合性能更为优异。
进一步地，步骤S2中，所述第一高温烧结的条件包括：烧结温度为750-900℃，优选为800-900℃；烧结时间为3-10h，优选为5-10h。
根据本发明，所述正极材料过程品I的D 50为2-5μm。
本发明中，所述正极材料过程品I为充分锂化的由一次颗粒组成的二次颗粒球。特别地，当所述正极材料过程品I的D 50满足上述范围时，由此制得的正极材料具有适宜的尺寸，并且具有高的压实密度、结构稳定并且能够保持较高的容量。
进一步地，所述正极材料过程品I的D 50为2-4.5μm，优选为2-4μm。
根据本发明，步骤S3中，所述第二高温烧结的条件包括：烧结温度为720-1200℃，烧结时间为5-20h。
本发明中，在上述条件下对正极材料过程品I进行第二高温烧结，能够使得制得的正极材料具有适宜的单晶尺寸大小，并且正极材料的颗粒尺寸均匀，球形度好。
本发明中，优选地，对正极材料过程品I进行破碎后，进行所述第二高温烧结。
进一步地，步骤S3中，所述第二高温烧结的条件包括：烧结温度为850-1150℃，优选为800-1100℃；烧结时间为8-20h，优选为10-18h。
根据本发明，所述第二高温烧结的温度比所述第一高温烧结的温度高，优选高20-200℃；更优选高30-100℃，进一步优选高40-60℃。
本发明中，控制第二高温烧结的温度比第一高温烧结的温度高20-200℃，能够确保经第一高温烧结得到正极材料过程品I，既充分锂化又能保证二次颗粒球的状态，如果第一高温烧结温度过低，无法实现充分锂化，如果第一高温烧结温度过高，则导致正极材料过程品I成为单晶结构。
根据本发明，所述正极材料过程品II的D 50为2-5μm，优选为2-4μm。
根据本发明，步骤S4中，所述包覆剂E选自含有Al、Nb、Co、Mn、Mo、 W、Si、Mg、Ti和Zr中的至少一种元素的氧化物、羟基氧化物、氢氧化物、碳酸盐和草酸盐中的至少一种。具体地，所述包覆剂E选自氧化镁、氧化硅、氧化钨和氧化锆中的至少一种。
根据本发明，所述包覆剂E的加入量按照化学计量比为0≤[n(E)]/[n(Ni)+n(Co)+n(Mn)]≤0.05添加。
进一步地，所述包覆剂E的加入量按照化学计量比为0.001≤[n(E)]/[n(Ni)+n(Co)+n(Mn)]≤0.03添加。
根据本发明，步骤S5中，所述第三高温烧结的条件包括：烧结温度为500-900℃，烧结时间为3-10h。
本发明中，在上述条件下对正极材料过程品II与包覆剂E的混合物进行第三高温烧结，能够修饰正极材料表面缺陷，并起到稳定晶体表面结构的作用。
本发明中，优选地，对正极材料过程品II进行破碎，并与包覆剂E进行混合后，进行所述第三高温烧结。
进一步地，步骤S5中，所述第三高温烧结的条件包括：烧结温度为600-900℃，优选为700-800℃；烧结时间为4-10h，优选为6-10h。
本发明中，所述镍钴锰氢氧化物前驱体可以为本领域中常规的前驱体，优选地，所述镍钴锰氢氧化物前驱体为含有Ni、Co、Mn和掺杂剂A的氢氧化物。进一步地，所述镍钴锰氢氧化物前驱体为球形或类球形单一颗粒。
本发明的一个具体实施方式中，所述镍钴锰氢氧化物前驱体按照以下步骤制得：
(1)将镍盐、钴盐、锰盐按照Ni∶Co∶Mn＝x∶z∶y的摩尔比配制混合盐溶液；将掺杂剂A、沉淀剂分别配制为掺杂剂A盐溶液和沉淀剂溶液；
(2)在氮气气氛下，将混合盐溶液、沉淀剂溶液、氨水和可选的掺杂剂A盐溶液加入反应釜进行连续反应、陈化，得到固液混合浆料；
(3)将所述固液混合浆料经压滤、洗涤、烘干，得到镍钴锰氢氧化物前驱体。
本发明中，所述镍盐、所述钴盐和所述锰盐可以为本领域中常规的镍盐、钴盐和锰盐。具体地，所述镍盐选自硫酸镍和/或氯化镍；所述钴盐选自硫酸钴和/或氯化钴；所述锰盐选自硫酸锰和/或氯化锰。
本发明中，所述沉淀剂可以为本领域中常规的沉淀剂，例如氢氧化钠、氢氧化钾、碳酸钠和碳酸铵中的至少一种。所述络合剂可以为本领域中常规的络合剂，例如氨水。
根据本发明，所述混合盐的浓度为1-3mol/L；所述沉淀剂溶液的浓度为5-10mol/L；所述氨水的质量浓度为20-30wt％。
根据本发明，所述掺杂剂A选自含有V、Ta、Cr、La、Ce、Er和Y中的至少一种元素的可溶盐和/或溶胶。具体地，所述掺杂剂A选自硝酸铒、硫酸钇和硝酸镧中的一种。
根据本发明，所述掺杂剂A的加入量按照化学计量比为0≤[n(A)]/[n(Ni)+n(Co)+n(Mn)]≤0.05添加。
进一步地，所述掺杂剂A的加入量按照化学计量比为0.001≤[n(A)]/[n(Ni)+n(Co)+n(Mn)]≤0.03添加。
根据本发明，所述连续反应的条件包括：pH值为11-13，反应温度为40-60℃，溶液停留时间为6-30h。
根据本发明，所述含掺杂剂A的镍钴锰氢氧化物前驱体的D 50为2-6μm， 松装密度为0.6-1g/cm 3，振实密度为1.2-1.6g/cm 3。
进一步地，所述含掺杂剂A的镍钴锰氢氧化物前驱体的D 50为2.5-5.5μm，松装密度为0.6-0.9g/cm 3，振实密度为1.2-1.55g/cm 3。
本发明第三方面提供由上述制备方法制得的单晶型多元正极材料；
根据本发明，所述正极材料满足以下条件：
(1)正极材料通过SEM测得的单晶尺寸D PS90、D PS10与D PS50满足以下关系：0.1≤B 90＝(D PS90-D PS10)/D PS50≤1.5；
(2)所述正极材料的团聚率≤20％；
其中，D PS90正极材料的单晶尺寸90％小于D PS90；D PS50正极材料的单晶尺寸50％小于D PS50；D PS10正极材料的单晶尺寸10％小于D PS10。
进一步地，正极材料通过SEM测得的单晶尺寸D PS90、D PS10与D PS50满足以下关系：0.1≤B 90＝(D PS90-D PS10)/D PS50≤1.3；优选地，0.1≤B 90＝(D PS90-D PS10)/D PS50≤1.1。
进一步地，所述正极材料的团聚率≤15％，优选≤10％。
根据本发明，所述正极材料的平均单晶尺寸D PS50为1-3μm。
进一步地，所述正极材料的平均单晶尺寸D PS50为1.2-2.8μm，优选为1.5-2.5μm。
根据本发明，所述正极材料满足如下条件：0.1≤H PS≤0.5；
其中，H PS为多个晶粒颗粒H PSn的统计平均数，H PSn为单个颗粒计算结果，H PSn＝2(D PSLn-D PSSn)/(D PSLn+D PSSn)，D PSLn为正极材料通过SEM测得的单个晶粒颗粒n的最长对角线长度，D PSSn为正极材料通过SEM测得的单个晶粒颗粒n的最短对角线长度。
进一步地，0.1≤H PS≤0.4，更进一步地，0.1≤H PS≤0.3。
根据本发明，所述正极材料的D 50为2-5μm，优选为2-4μm，更优选为2.5-3.8μm。
根据本发明，所述正极材料具有式I所示的组成：
Li 1+a(A mD nNi xMn yCo z)E iO 2式I
其中，-0.1≤a≤0.1，0≤m≤0.05，0≤n≤0.05，0.5≤x＜1，0＜y＜0.5，0≤z＜0.5，0≤i≤0.05；A选自V、Ta、Cr、La、Ce、Er和Y中的至少一种；D选自Mg、Sr、B、V、Al、Ca、Zn、Ba、Ra、Zr和Ti中的至少一种；E选自Al、Nb、Co、Mn、Mo、W、Si、Mg、Ti和Zr中的至少一种。
进一步地，0≤a≤0.08，0.001≤m≤0.03，0.001≤n≤0.03，0.7≤x＜0.9，0.1＜y＜0.3，0.1≤z＜0.3，0.001≤i≤0.03；A选自La、Ce、Er和Y中的至少一种；D选自Sr、B、V、Al和Ca中的至少一种；E选自W、Si、Mg、Ti和Zr中的至少一种。
本发明中，所述单晶型多元正极材料的压实密度PD≥3.3g/cm 3，优选为3.3-3.6g/cm 3。
本发明第四方面提供一种上述单晶型多元正极材料在锂离子电池中的应用。
以下将通过实施例对本发明进行详细描述。以下实施例中，
正极材料的D 50为激光粒度仪测试的结果；
正极材料的单晶尺寸采用SEM标尺为基准获得；
正极材料的压实密度采用压实密度测试仪测得；
镍钴锰氢氧化物前驱体的松装密度、振实密度分别采用振实密度测试仪测得；
扣式电池的电化学性能：
在3.0-4.3V电压下，0.1C首次放电比容量、1.0C的放电比容量以及1C/1C@45℃条件下80周循环容量保持率；
循环性能测试如下：使用已活化电池，以1C的电流密度在3.0-4.3V的电压区间，在45℃温度下，循环80次考察材料的高温容量保持率。
关于制作的扣式电池的性能评价如下定义：
制作扣式电池后放置2h，开路电压稳定后，对正极以0.1C的电流密度充电至截止电压4.3V，再恒压充电30min，随后以同样的电流密度放电至截止电压3.0V；按同样的方式再进行1次，将此时的电池作为已活化电池。
循环性能测试如下：使用已活化电池，以1C的电流密度在3.0-4.3V的电压区间，在45℃温度下，循环80次考察材料的高温容量保持率。
电性能测试参数通过深圳新威CT-3008电池测试系统进行测试。
Li 2CO 3及LiOH含量通过电位滴定获得。
实施例以及对比例所用原料均为市售品。
实施例1
I：镍钴锰氢氧化物前驱体的制备
(1)以硫酸镍、硫酸钴、硫酸锰为原料，按照摩尔比Ni∶Co∶Mn＝80∶10∶10调配成2mol/L的均匀镍、钴、锰盐混合溶液，并配制0.2mol/L的La 2(SO 4) 3溶液，调配8mol/L的NaOH溶液作为沉淀剂，25wt％的氨水直接使用作为络合剂。
(2)在氮气保护下，将上述溶液以并流的方式通入反应釜中，控制[n(Ni)+n(Co)+n(Mn)]∶n(La)＝1∶0.01，搅拌转速200rpm，反应温度保持在55℃，pH值为12.3，并流时间为23h，陈化20h，得到固液混合浆料。
(3)将所述固液混合浆料经压滤、洗涤、在120℃温度下烘干5h后，即可得到D 50为3.3μm含掺杂剂La的镍钴锰氢氧化物前驱体P1，该前驱体为球形或类球形单一颗粒，结构疏松，松装密度为0.72g/cm 3，振实密度为1.34g/cm 3。
II：单晶型多元正极材料的制备
S1、将镍钴锰氢氧化物前驱体P1、氢氧化锂、氧化钙按照[n(Ni)+n(Co)+n(Mn)]∶n(Li)∶n(Ca)＝1∶1.05∶0.008的比例，在高混机中均匀混合，得到混合物I；
S2、在氧气气氛下，对混合物I于850℃进行第一高温烧结8h，自然冷却至室温，破碎过筛得正极材料过程品I，D 50为3.2μm。
S3、在氧气气氛下，对正极材料过程品I于900℃进行第二高温烧结8h，自然冷却至室温，破碎过筛得正极材料过程品II，D 50为3.2μm，一次颗粒相互独立。第二高温烧结的温度比第一高温烧结的温度高50℃。
S4、将正极材料过程品II、氧化镁按照[n(Ni)+n(Co)+n(Mn)]∶n(Mg)＝1∶0.012的比例，在高混机中均匀混合，得到混合物II；
S5、在氧气气氛下，对混合物II于750℃进行第三高温烧结10h，自然冷却至室温，破碎过筛得单晶型多元正极材料A1。其组成为Li 1.05(La 0.01Ca 0.008Ni 0.8Co 0.1Mn 0.1)Mg 0.012O 2。正极材料A1的性能参数如表1所示。
图1为实施例1制得的正极材料过成品I的SEM图；从图1中能够看出，正极材料过成品I为团聚型化合物。图2为实施例1制得正极材料过成品II的SEM图；从图2中能够看出，正极材料过成品II为单晶型化合物。图3为单晶型多元正极材料A1的SEM图；从图3中能够看出，正极材料A1为具有表面包 覆层的单晶型化合物。
实施例2
I：镍钴锰氢氧化物前驱体的制备
(1)以硫酸镍、硫酸钴、硫酸锰为原料，按照摩尔比Ni∶Co∶Mn＝80∶10∶10调配成2mol/L的均匀镍、钴、锰盐混合溶液，并配制0.2mol/L的Ce 2(SO 4) 3溶液，调配8mol/L的KOH溶液作为沉淀剂，25wt％的氨水直接使用作为络合剂。
(2)在氮气保护下，将上述溶液以并流的方式通入反应釜中，控制[n(Ni)+n(Co)+n(Mn)]∶n(Ce)＝1∶0.015，搅拌转速200rpm，反应温度保持在55℃，pH值为12.3，并流时间为20h，陈化20h，得到固液混合浆料。
(3)将所述固液混合浆料经洗涤、压滤、在110℃温度下烘干5.5h后，即可得到D 50为4μm含掺杂剂Ce的镍钴锰氢氧化物前驱体P2，该前驱体为球形或类球形单一颗粒，结构疏松，松装密度为0.73g/cm 3，振实密度为1.35g/cm 3。
II：单晶型多元正极材料的制备
S1、将镍钴锰氢氧化物前驱体、氢氧化锂、氧化锶按照[n(Ni)+n(Co)+n(Mn)]∶n(Li)∶n(Sr)＝1∶1.05∶0.012的比例，在高混机中均匀混合，得到混合物II；
S2、在氧气气氛下，对混合物I于840℃进行第一高温烧结4h，自然冷却至室温，破碎过筛得正极材料过程品I，D 50为3.1μm。
S3、在氧气气氛下，对正极材料过程品I于900℃进行第二高温烧结5h，自然冷却至室温，破碎过筛得正极材料过程品II，D 50为3.0μm，一次颗粒相互独立。第二高温烧结的温度比第一高温烧结的温度高60℃。
S4、将正极材料过程品II、氧化硅按照[n(Ni)+n(Co)+n(Mn)]∶n(Si)＝1∶0.01的比例，在高混机中均匀混合，得到混合物II；
S5、在氧气气氛下，对混合物II于720℃进行第三高温烧结10h，自然冷却至室温，破碎过筛得单晶型多元正极材料A2。其组成为Li 1.05(Ce 0.015Sr 0.012Ni 0.8Co 0.1Mn 0.1)Si 0.01O 2。正极材料A2的性能参数如表1所示。
实施例3
I：镍钴锰氢氧化物前驱体的制备
(1)以硫酸镍、硫酸钴、硫酸锰为原料，按照摩尔比Ni∶Co∶Mn＝80∶10∶10调配成2mol/L的均匀镍、钴、锰盐混合溶液，并配制0.2mol/L的Er(NO 3) 3溶液，调配8mol/L的NaOH溶液作为沉淀剂，25wt％的氨水直接使用作为络合剂。
(2)在氮气保护下，将上述溶液以并流的方式通入反应釜中，控制[n(Ni)+n(Co)+n(Mn)]∶n(Er)＝1∶0.015，搅拌转速200rpm，反应温度保持在56℃，pH值为12.4，并流时间为24h，陈化20h，得到固液混合浆料。
(3)将所述固液混合浆料经洗涤、压滤、在120℃温度下烘干6h后，即可得到D 50为3.9μm含掺杂剂Er的镍钴锰氢氧化物前驱体P3，该前驱体为球形或类球形单一颗粒，结构疏松，松装密度为0.71g/cm 3，振实密度为1.33g/cm 3。
II：单晶型多元正极材料的制备
S1、将镍钴锰氢氧化物前驱体P3、氢氧化锂、氧化硼按照[n(Ni)+n(Co)+n(Mn)]∶n(Li)∶n(B)＝1∶1.04∶0.009的比例，在高混机中均匀混合，得到混合物I；
S2、在氧气气氛下，对混合物I于860℃进行第一高温烧结10h，自然冷却 至室温，破碎过筛得正极材料过程品I，D 50为3.8μm。
S3、在氧气气氛下，对正极材料过程品I于900℃进行第二高温烧结15h，自然冷却至室温，破碎过筛得正极材料过程品II，D 50为3.7μm，一次颗粒相互独立。第二高温烧结的温度比第一高温烧结的温度高40℃。
S4、将正极材料过程品II、氧化钨按照[n(Ni)+n(Co)+n(Mn)]∶n(W)＝1∶0.01的比例，在高混机中均匀混合，得到混合物II。
S5、在空气气氛下，对混合物II于780℃进行第三高温烧结6h，自然冷却至室温，破碎过筛得单晶型多元正极材料A3。其组成为：Li 1.04(Er 0.015B 0.009Ni 0.8Co 0.1Mn 0.1)W 0.01O 2。正极材料A3的性能参数如表1所示。
实施例4
I：镍钴锰氢氧化物前驱体的制备
(1)以硫酸镍、硫酸钴、硫酸锰为原料，按照摩尔比Ni∶Co∶Mn＝50∶20∶30调配成2mol/L的均匀镍、钴、锰盐混合溶液，并配制0.2mol/L的Cr 2(SO 4) 3溶液，调配8mol/L的NaOH溶液作为沉淀剂，25wt％的氨水直接使用作为络合剂。
(2)在氮气保护下，将上述溶液以并流的方式通入反应釜中，控制[n(Ni)+n(Co)+n(Mn)]∶n(Cr)＝1∶0.005，搅拌转速200rpm，反应温度保持在52℃，pH值为12.3，并流时间为19h，陈化20h，得到固液混合浆料。
(3)将固液混合浆料经洗涤、压滤、在100℃温度下烘干7h后，即可得到D 50为4.1μm含掺杂剂Cr的镍钴锰氢氧化物前驱体P4，该前驱体为球形或类球形单一颗粒，结构疏松，松装密度为0.70g/cm 3，振实密度为1.31g/cm 3。
II：单晶型多元正极材料的制备
S1、将镍钴锰氢氧化物前驱体P4、碳酸锂、氟化铝按照[n(Ni)+n(Co)+n(Mn)]∶n(Li)∶n(Al)＝1∶1.05∶0.01的比例，在高混机中均匀混合，得到混合物I；
S2、在空气气氛下，对混合物I于960℃进行第一高温烧结10h，自然冷却至室温，破碎过筛得正极材料过程品I，D 50为3.4μm。
S3、在空气气氛下，对正极材料过程品I于980℃进行第二高温烧结12h，自然冷却至室温，破碎过筛得正极材料过程品II，D 50为3.3μm，一次颗粒相互独立。第二高温烧结的温度比第一高温烧结的温度高20℃。
S4、将正极材料过程品II、氧化锆按照[n(Ni)+n(Co)+n(Mn)]∶n(Zr)＝1∶0.015的比例，在高混机中均匀混合，得到混合物II；
S5、在空气气氛下，对混合物II于820℃进行第三高温烧结9h，自然冷却至室温，破碎过筛得单晶型多元正极材料A4。其组成为：Li 1.05(Cr 0.005Al 0.01Ni 0.5Co 0.2Mn 0.3)Zr 0.015O 2。正极材料A4的性能参数如表1所示。
实施例5
I：镍钴锰氢氧化物前驱体的制备
(1)以硫酸镍、硫酸钴、硫酸锰为原料，按照摩尔比Ni∶Co∶Mn＝95∶3∶2调配成2mol/L的均匀镍、钴、锰盐混合溶液，并配制0.2mol/L的Y(NO 3) 3溶液，调配8mol/L的NaOH溶液作为沉淀剂，25wt％的氨水直接使用作为络合剂。
(2)在氮气保护下，将上述溶液以并流的方式通入反应釜中，控制[n(Ni)+n(Co)+n(Mn)]∶n(Y)＝1∶0.012，搅拌转速200rpm，反应温度保持在55℃，pH值为12.3，并流时间为28h，陈化20h，得到固液混合浆料。
(3)将固液混合浆料经洗涤、压滤、在120℃温度下烘干6h后，即可得到D 50为4μm的镍钴锰氢氧化物前驱体P5，该前驱体为球形或类球形单一颗粒，结构疏松，松装密度为0.71g/cm 3，振实密度为1.32g/cm 3。
II：单晶型多元正极材料的制备
S1、将镍钴锰氢氧化物前驱体P5、氢氧化锂、氧化锌按照[n(Ni)+n(Co)+n(Mn)]∶n(Li)∶n(Zn)＝1∶1.08∶0.014的比例，在高混机中均匀混合，得到混合物I；
S2、在氧气气氛下，对混合物I于700℃进行第一高温烧结5h，自然冷却至室温，破碎过筛得正极材料过程品I，D 50为3.9μm。
S3、在氧气气氛下，将正极材料过程品I于800℃进行第二高温烧结10h，自然冷却至室温，破碎过筛得正极材料过程品II，D 50为4μm，一次颗粒相互独立。第二高温烧结的温度比第一高温烧结的温度高100℃。
S4、将正极材料过程品II、氧化钼按照[n(Ni)+n(Co)+n(Mn)]∶n(Mo)＝1∶0.008的比例，在高混机中均匀混合，得到混合物II；
S5、在氧气气氛下，对混合物II于600℃进行第三高温烧结10h，自然冷却至室温，破碎过筛得单晶型多元正极材料A5。其组成为：Li 1.08Y 0.012Zn 0.014Ni 0.95Co 0.03Mn 0.02)Mo 0.008O 2。正极材料A5的性能参数如表1所示。
实施例6
I：镍钴锰氢氧化物前驱体的制备
(1)以硫酸镍、硫酸钴、硫酸锰为原料，按照摩尔比Ni∶Co∶Mn＝80∶10∶10调配成2mol/L的均匀镍、钴、锰盐混合溶液，调配8mol/L的NaOH溶液作为沉淀剂，25wt％的氨水直接使用作为络合剂。
(2)在氮气保护下，将上述溶液以并流的方式通入反应釜中，搅拌转速200rpm，反应温度保持在55℃，pH值为12.3，并流时间为23h，陈化20h，得到固液混合浆料。
(3)将所述固液混合浆料经压滤、洗涤、在120℃温度下烘干5h后，即可得到D 50为3.2μm的镍钴锰氢氧化物前驱体P6，该前驱体为球形或类球形单一颗粒，结构疏松，松装密度为0.71g/cm 3，振实密度为1.33g/cm 3。
II：单晶型多元正极材料的制备
S1、将镍钴锰氢氧化物前驱体P6、氢氧化锂按照[n(Ni)+n(Co)+n(Mn)]∶n(Li)＝1∶1.05的比例，在高混机中均匀混合，得到混合物I；
S2、在氧气气氛下，对混合物I于850℃进行第一高温烧结8h，自然冷却至室温，破碎过筛得正极材料过程品I，D 50为3.1μm。
S3、在氧气气氛下，对正极材料过程品I于900℃进行第二高温烧结8h，自然冷却至室温，破碎过筛得正极材料过程品II，D 50为3.3μm，一次颗粒相互独立。第二高温烧结的温度比第一高温烧结的温度高50℃。
S4、在氧气气氛下，对混合物II于750℃进行第三高温烧结10h，自然冷却至室温，破碎过筛得单晶型多元正极材料A6。其组成为Li 1.05(Ni 0.8Co 0.1Mn 0.1)O 2。正极材料A6的性能参数如表1所示。
实施例7
按照实施例1的方法制备单晶型多元正极材料，不同的是：保持第二高温烧结的温度不变，调整第一高温烧结温度，使得第二高温烧结的温度比第一高温 烧结的温度高130℃。
制得单晶型多元正极材料A7，其性能参数如表1所示。
实施例8
按照实施例1的方法制备单晶型多元正极材料，不同的是：保持第二高温烧结的温度不变，调整第一高温烧结温度，使得第二高温烧结的温度比第一高温烧结的温度高180℃。
制得单晶型多元正极材料A8，其性能参数如表1所示。
实施例9
按照实施例1的方法制备单晶型多元正极材料，不同的是：保持第二高温烧结的温度不变，调整第一高温烧结温度，使得第二高温烧结的温度比第一高温烧结的温度高10℃。
制得单晶型多元正极材料A9，其性能参数如表1所示。
实施例10
按照实施例1的方法制备单晶型多元正极材料，不同的是：保持第二高温烧结的温度不变，调整第一高温烧结温度，使得第二高温烧结的温度比第一高温烧结的温度高400℃。
制得单晶型多元正极材料A10，其性能参数如表1所示。
实施例11
按照实施例1的方法制备单晶型多元正极材料，不同的是：保持第二高温烧结的温度不变，调整第一高温烧结温度，使得第二高温烧结的温度比第一高温烧结的温度低50℃。
制得单晶型多元正极材料A11，其性能参数如表1所示。
实施例12
I：镍钴锰氢氧化物前驱体的制备
(1)以硫酸镍、硫酸钴、硫酸锰为原料，按照摩尔比Ni∶Co∶Mn＝80∶10∶10调配成2mol/L的均匀镍、钴、锰盐混合溶液，并配制0.2mol/L的La 2(SO 4) 3溶液，调配8mol/L的NaOH溶液作为沉淀剂，25wt％的氨水直接使用作为络合剂。
(2)在氮气保护下，将上述溶液以并流的方式通入反应釜中，控制[n(Ni)+n(Co)+n(Mn)]∶n(La)＝1∶0.05，搅拌转速200rpm，反应温度保持在55℃，pH值为12.3，并流时间为23h，陈化20h，得到固液混合浆料。
(3)将所述固液混合浆料经压滤、洗涤、在120℃温度下烘干5h后，即可得到D 50为3.1μm含掺杂剂La的镍钴锰氢氧化物前驱体P1，该前驱体为球形或类球形单一颗粒，结构疏松，松装密度为0.72g/cm 3，振实密度为1.34g/cm 3。
II：单晶型多元正极材料的制备
S1、将镍钴锰氢氧化物前驱体P1、氢氧化锂、氧化钙按照[n(Ni)+n(Co)+n(Mn)]∶n(Li)∶n(Ca)＝1∶1.1∶0.05的比例，在高混机中均匀混合，得到混合物I；
S2、在氧气气氛下，对混合物I于700℃进行第一高温烧结8h，自然冷却 至室温，破碎过筛得正极材料过程品I，D 50为3.2μm。
S3、在氧气气氛下，对正极材料过程品I于900℃进行第二高温烧结8h，自然冷却至室温，破碎过筛得正极材料过程品II，D 50为3.2μm，一次颗粒相互独立。第二高温烧结的温度比第一高温烧结的温度高200℃。
S4、将正极材料过程品II、氧化镁按照[n(Ni)+n(Co)+n(Mn)]∶n(Mg)＝1∶0.05的比例，在高混机中均匀混合，得到混合物II；
S5、在氧气气氛下，对混合物II于800℃进行第三高温烧结10h，自然冷却至室温，破碎过筛得单晶型多元正极材料A12。其组成为Li 1.1(La 0.05Ca 0.05Ni 0.8Co 0.1Mn 0.1)Mg 0.05O 2。正极材料A12的性能参数如表1所示。
图4为实施例12制得的正极材料过成品I的SEM图；从图4中能够看出，正极材料过成品I为团聚型化合物。图5为实施例12制得正极材料过成品II的SEM图；从图5中能够看出，正极材料过成品II为单晶型化合物。图6为单晶型多元正极材料A12的SEM图；从图6中能够看出，正极材料A12为具有表面包覆层的单晶型化合物。
对比例1
I：镍钴锰氢氧化物前驱体的制备
按照实施例1的方法制备镍钴锰氢氧化物前驱体。
II：单晶型多元正极材料的制备
按照实施例1的方法制备单晶型多元正极材料，不同的是：不进行步骤S2，将混合物I直接进行第二高温烧结。制得单晶型多元正极材料D1。其组成为：Li 1.05(La 0.01Ca 0.008Ni 0.8Co 0.1Mn 0.1)Mg 0.012O 2。正极材料D1的性能参数如表1所示。图7为正极材料D1的SEM图，从图7中能够看出，该材料大小不均一，团聚率较高，单晶化较差。
对比例2
I：镍钴锰氢氧化物前驱体的制备
(1)硫酸镍、硫酸钴、硫酸锰为原料，按照摩尔比Ni∶Co∶Mn＝50∶20∶30调配成2mol/L的均匀镍、钴、锰盐混合溶液，并配制0.2mol/L的Cr 2(SO 4) 3溶液。调配8mol/L的NaOH溶液作为沉淀剂，25wt％的氨水直接使用作为络合剂。
(2)在氮气保护下，将上述溶液以并流的方式通入反应釜中，控制[n(Ni)+n(Co)+n(Mn)]∶n(Cr)＝1∶0.01，搅拌转速200rpm，反应温度保持在55℃，pH值为12.3，并流时间为23h，陈化20h，得到固液混合浆料。
(3)固液混合浆料经洗涤、压滤、在100℃温度下烘干5h后，即可得到D 50为4.5μm的镍钴锰氢氧化物前驱体PD2，该前驱体为球形或类球形单一颗粒，结构疏松，松装密度为0.72g/cm 3，振实密度为1.34g/cm 3。
II：单晶型多元正极材料的制备
S1、将镍钴锰氢氧化物前驱体PD2、氢氧化锂、氧化铝按照[n(Ni)+n(Co)+n(Mn)]∶n(Li)∶n(Al)＝1∶1.06∶0.01的比例，在高混机中均匀混合，得到混合物I；
S2、在空气气氛下，对混合物I于980℃进行第二高温烧结12h，自然冷却至室温，破碎过筛得正极材料过程品II，D 50为3.4μm。
S3、将正极材料过程品II、氧化硅按照[n(Ni)+n(Co)+n(Mn)]∶n(Zr)＝1∶0.01的 比例，在高混机中均匀混合，得到混合物II；
S4、在空气气氛下，对混合物II于820℃进行第三高温烧结9h，自然冷却至室温，破碎过筛得单晶型多元正极材料D2。其组成为：Li 1.06(Cr 0.01Al 0.01Ni 0.5Co 0.2Mn 0.3)Zr 0.01O 2。正极材料D2的性能参数如表1所示。
对比例3
I：镍钴锰氢氧化物前驱体的制备
(1)硫酸镍、硫酸钴、硫酸锰为原料，按照摩尔比Ni∶Co∶Mn＝95∶3∶2调配成2mol/L的均匀镍、钴、锰盐混合溶液，并配制0.2mol/L的Y(NO 3) 3溶液。调配8mol/L的NaOH溶液作为沉淀剂，25wt％的氨水直接使用作为络合剂。
(2)在氮气保护下，将上述溶液以并流的方式通入反应釜中，控制[n(Ni)+n(Co)+n(Mn)]∶n(Y)＝1∶0.01，搅拌转速200rpm，反应温度保持在55℃，pH值为12.3，并流时间为23h，陈化20h，得到固液混合浆料。
(3)固液混合浆料经洗涤、压滤、在100℃温度下烘干5h后，即可得到D 50为3.1μm的镍钴锰氢氧化物前驱体PD3，该前驱体为球形或类球形单一颗粒，结构疏松，松装密度为0.72g/cm 3，振实密度为1.34 g/cm 3。
II：单晶型多元正极材料的制备
S1、将镍钴锰氢氧化物前驱体PD3、氢氧化锂、氧化锌按照[n(Ni)+n(Co)+n(Mn)]∶n(Li)∶n(Zn)＝1∶1.06∶0.01的比例，在高混机中均匀混合，得到混合物I；
S2、在氧气气氛下，对混合物I于800℃进行第二高温烧结10h，自然冷却至室温，破碎过筛得正极材料过程品II，D 50为3.0μm。
S3、将正极材料过程品II、氧化钼按照[n(Ni)+n(Co)+n(Mn)]∶n(Mo)＝1∶0.01的比例，在高混机中均匀混合，得到混合物II；
S4、在氧气气氛下，对混合物II于600℃进行第三高温烧结7h，自然冷却至室温，破碎过筛得单晶型多元正极材料D3。其组成为：Li 1.06(Y 0.01Zn 0.01Ni 0.95Co 0.03Mn 0.02)Mo 0.01O 2。正极材料D3的性能参数如表1所示。
表1
Figure PCTCN2022091942-appb-000001
Figure PCTCN2022091942-appb-000002
测试例
将实施例以及对比例的正极材料作为正极，制备扣式电池，具体的制备方法如下：
扣式电池的制作：
首先，将非水系电解质二次电池用复合镍钴锰多元正极活性物质、乙炔黑及聚偏二氟乙烯(PVDF)按照质量比95∶3∶2进行混合，涂覆在铝箔上并进行烘干处理，用100MPa的压力冲压成型为直径12mm、厚120μm的正极极片，然后将正极极片放入真空烘干箱中120℃烘干12h。
负极使用直径为17mm，厚度为1mm的Li金属片；隔膜使用厚度为25μm的聚乙烯多孔膜；电解液使用1mol/L的LiPF 6、碳酸乙烯酯(EC)和碳酸二乙酯(DEC)的等量混合液。
将正极极片、隔膜、负极极片及电解液在水含量与氧含量均小于5ppm的Ar气手套箱内组装成2025型扣式电池，将此时的电池作为未活化电池。
对扣式电池的电化学性能进行测试，测试结果如表2所示。
表2
Figure PCTCN2022091942-appb-000003
图8为实施例1与对比例1的1C/1C@45℃循环80周的对比图，由图8可以看出，实施例1的容量略高于对比例1，实施例1的循环保持率明显高于对比例1，且随着循环进行，实施例1的容量稳定下降，而对比例1的容量下降趋势变快明显增快。
通过实施例和对比例的结果可以看出：
(1)实施例1-3采用本发明的优选范围内的条件，结果制备得到的正极材料D PS适中，B 90及H PS较小，说明单晶圆润，球型度好，且大小均一，团聚率也较低，且容量较高，循环较好。
(2)实施例7-12没有采用本发明的优选范围内的条件，结果制备得到的正极材料的单晶化及性能相对于实施例1-3略差，但比对比例1-3好。
(3)对比例1-3没有采用本发明的制备方法，结果得到的正极材料的性能较差。
以上详细描述了本发明的优选实施方式，但是，本发明并不限于此。在本发明的技术构思范围内，可以对本发明的技术方案进行多种简单变型，包括各个技术特征以任何其它的合适方式进行组合，这些简单变型和组合同样应当视为本发明所公开的内容，均属于本发明的保护范围。

Claims (10)

  1. 一种单晶型多元正极材料，其特征在于，所述正极材料满足以下条件：
    (1)正极材料通过SEM测得的单晶尺寸D PS90、D PS10与D PS50满足以下关系：0.1≤B 90＝(D PS90-D PS10)/D PS50≤1.5；
    (2)所述正极材料的团聚率≤20％；
    其中，D PS90正极材料的单晶尺寸90％小于D PS90；D PS50正极材料的单晶尺寸50％小于D PS50；D PS10正极材料的单晶尺寸10％小于D PS10。
  2. 根据权利要求1所述的单晶型多元正极材料，其中，正极材料通过SEM测得的单晶尺寸D PS90、D PS10与D PS50满足以下关系：0.1≤B 90＝(D PS90-D PS10)/D PS50≤1.3；
    优选地，所述正极材料的团聚率≤15％。
  3. 根据权利要求1或2所述的单晶型多元正极材料，其中，所述正极材料的平均单晶尺寸D PS50为1-3μm，优选为1.2-2.8μm；
    优选地，所述正极材料满足如下条件：0.1≤H PS≤0.5，优选地，0.1≤H PS≤0.4；
    其中，H PS为多个晶粒颗粒H PSn的统计平均数，H PSn为单个颗粒计算结果，H PSn＝2(D PSLn-D PSSn)/(D PSLn+D PSSn)，D PSLn为正极材料通过SEM测得的单个晶粒颗粒n的最长对角线长度，D PSSn为正极材料通过SEM测得的单个晶粒颗粒n的最短对角线长度；
    优选地，所述正极材料的D 50为2-5μm，优选为2-4μm。
  4. 根据权利要求1-3中任意一项所述的单晶型多元正极材料，其中，所述正极材料具有式I所示的组成：
    Li 1+a(A mD nNi xMn yCo z)E iO 2式I
    其中，-0.1≤a≤0.1，0≤m≤0.05，0≤n≤0.05，0.5≤x＜1，0＜y＜0.5，0≤z＜0.5，0≤i≤0.05；A选自V、Ta、Cr、La、Ce、Er和Y中的至少一种；D选自Mg、Sr、B、V、Al、Ca、Zn、Ba、Ra、Zr和Ti中的至少一种；E选自Al、Nb、Co、Mn、Mo、W、Si、Mg、Ti和Zr中的至少一种。
  5. 一种单晶型多元正极材料的制备方法，其特征在于，所述方法包括以下步骤：
    S1、将镍钴锰氢氧化物前驱体、锂源、可选地掺杂剂D进行混合，得到混合物I；
    S2、在氧气或空气气氛中，对所述混合物I进行第一高温烧结，得到正极材料过程品I；
    S3、在氧气或空气气氛中，对所述正极材料过程品I进行第二高温烧结，得到正极材料过程品II；
    S4、将所述正极材料过程品II与可选地包覆剂E进行混合，得到混合物II；
    S5、在氧气或空气气氛中，对所述混合物II进行第三高温烧结，得到所述单晶型多元正极材料。
  6. 根据权利要求5所述的制备方法，其中，步骤S1中，所述锂源选自碳酸锂、硝酸锂、氢氧化锂、氧化锂和醋酸锂中的至少一种；
    优选地，所述锂源的加入量按照化学计量比为0.9≤[n(Li)]/[n(Ni)+n(Co)+n(Mn)]≤1.1添加；
    优选地，所述掺杂剂D选自含有Mg、Sr、B、V、Al、Ca、Zn、Ba、Ra、Zr和Ti中至少一种元素的氧化物、羟基氧化物、氢氧化物、碳酸盐和草酸盐中的至少一种；
    优选地，所述掺杂剂D的加入量按照化学计量比为0≤[n(D)]/[n(Ni)+n(Co)+n(Mn)]≤0.05添加；
    优选地，步骤S2中，所述第一高温烧结的条件包括：烧结温度为700-1000℃，烧结时间为2-10h；
    优选地，所述正极材料过程品I的D 50为2-5μm；
    优选地，步骤S3中，所述第二高温烧结的条件包括：烧结温度为720-1200℃，烧结时间为5-20h；
    优选地，所述正极材料过程品II的D 50为2-5μm；
    优选地，所述第二高温烧结的温度比所述第一高温烧结的温度高，优选高20-200℃；
    优选地，步骤S4中，所述包覆剂E选自含有Al、Nb、Co、Mn、Mo、W、Si、Mg、Ti和Zr中的至少一种元素的氧化物、羟基氧化物、氢氧化物、碳酸盐和草酸盐中的至少一种；
    优选地，所述包覆剂E的加入量按照化学计量比为0≤[n(E)]/[n(Ni)+n(Co)+n(Mn)]≤0.05添加；
    优选地，步骤S5中，所述第三高温烧结的条件包括：烧结温度为500-900℃，烧结时间为3-10h。
  7. 根据权利要求5或6所述的制备方法，其中，所述镍钴锰氢氧化物前驱体按照以下步骤制得：
    (1)将镍盐、钴盐、锰盐按照Ni∶Co∶Mn＝x∶z∶y的摩尔比配制混合盐溶液；将掺杂剂A、沉淀剂分别配制为掺杂剂A盐溶液和沉淀剂溶液；
    (2)在氮气气氛下，将混合盐溶液、沉淀剂溶液、氨水和可选地掺杂剂A盐溶液加入反应釜进行连续反应、陈化，得到固液混合浆料；
    (3)将所述固液混合浆料经压滤、洗涤、烘干，得到镍钴锰氢氧化物前驱体。
  8. 根据权利要求7所述的制备方法，其中，所述混合盐的浓度为1-3mol/L；所述沉淀剂溶液的浓度为5-10mol/L；所述氨水的质量浓度为20-30wt％；
    优选地，所述掺杂剂A选自含有V、Ta、Cr、La、Ce、Er和Y中的至少一种元素的可溶盐和/或溶胶；
    优选地，所述掺杂剂A的加入量按照化学计量比为0≤[n(A)]/[n(Ni)+n(Co)+n(Mn)]≤0.05添加；
    优选地，所述连续反应的条件包括：pH值为11-13，反应温度为40-60℃，并流时间为6-30h；
    优选地，所述陈化的条件包括：陈化温度为40-60℃，陈化时间为5-30h；
    优选地，所述含掺杂剂A的镍钴锰氢氧化物前驱体的D 50为2-6μm，松装 密度为0.6-1g/cm 3，振实密度为1.2-1.6g/cm 3。
  9. 由权利要求5-8中任意一项所述的制备方法制得的单晶型多元正极材料；
    优选地，所述正极材料满足以下条件：
    (1)正极材料通过SEM测得的单晶尺寸D PS90、D PS10与D PS50满足以下关系：0.1≤B 90＝(D PS90-D PS10)/D PS50≤1.5，优选为0.1≤B 90＝(D PS90-D PS10)/D PS50≤1.3；
    (2)所述正极材料的团聚率≤20％，优选≤15％；
    其中，D PS90正极材料的单晶尺寸90％小于D PS90；D PS50正极材料的单晶尺寸50％小于D PS50；D PS10正极材料的单晶尺寸10％小于D PS10；
    优选地，所述正极材料的平均单晶尺寸D PS50为1-3μm，优选为1.2-2.8μm；
    优选地，所述正极材料满足如下条件：0.1≤H PS≤0.5；
    其中，H PS为多个晶粒颗粒H PSn的统计平均数，H PSn为单个颗粒计算结果，H PSn＝2(D PSLn-D PSSn)/(D PSLn+D PSSn)，D PSLn为正极材料通过SEM测得的单个晶粒颗粒n的最长对角线长度，D PSSn为正极材料通过SEM测得的单个晶粒颗粒n的最短对角线长度；
    优选地，0.1≤H PS≤0.5；
    优选地，所述正极材料的D 50为2-5μm，优选为2-4μm；
    优选地，所述正极材料具有式I所示的组成：
    Li 1+a(A mD nNi xMn yCo z)E iO 2式I
    其中，-0.1≤a≤0.1，0≤m≤0.05，0≤n≤0.05，0.5≤x＜1，0＜y＜0.5，0≤z＜0.5，0≤i≤0.05；A选自V、Ta、Cr、La、Ce、Er和Y中的至少一种；D选自Mg、Sr、B、V、Al、Ca、Zn、Ba、Ra、Zr和Ti中的至少一种；E选自Al、Nb、Co、Mn、Mo、W、Si、Mg、Ti和Zr中的至少一种。
  10. 一种权利要求1-4和9中任意一项所述的单晶型多元正极材料在锂离子电池中的应用。
PCT/CN2022/091942 2021-12-24 2022-05-10 单晶型多元正极材料及其制备方法与应用 WO2022207008A1 (zh)

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