WO2024055513A1 - 一种正极材料前驱体、正极材料及其制备方法和应用 - Google Patents

一种正极材料前驱体、正极材料及其制备方法和应用 Download PDF

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WO2024055513A1
WO2024055513A1 PCT/CN2023/077443 CN2023077443W WO2024055513A1 WO 2024055513 A1 WO2024055513 A1 WO 2024055513A1 CN 2023077443 W CN2023077443 W CN 2023077443W WO 2024055513 A1 WO2024055513 A1 WO 2024055513A1
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cathode material
precursor
material precursor
positive electrode
particle size
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PCT/CN2023/077443
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English (en)
French (fr)
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汪乾
阮丁山
李长东
刘伟健
刘更好
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广东邦普循环科技有限公司
湖南邦普循环科技有限公司
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Publication of WO2024055513A1 publication Critical patent/WO2024055513A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/006—Compounds containing, besides nickel, two or more other elements, with the exception of oxygen or hydrogen
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/40—Nickelates
    • C01G53/42—Nickelates containing alkali metals, e.g. LiNiO2
    • C01G53/44—Nickelates containing alkali metals, e.g. LiNiO2 containing manganese
    • C01G53/50—Nickelates containing alkali metals, e.g. LiNiO2 containing manganese of the type [MnO2]n-, e.g. Li(NixMn1-x)O2, Li(MyNixMn1-x-y)O2
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—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
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
    • 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
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/51—Particles with a specific particle size distribution
    • 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
    • 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 belongs to the technical field of positive electrode materials for lithium ion batteries, and particularly relates to a positive electrode material precursor, a positive electrode material and a preparation method and application thereof.
  • the precursors for preparing lithium-ion battery cathode materials are usually prepared by co-precipitation method. During the process, the nucleation and growth of crystals are mainly controlled through precipitation reaction and complexation reaction.
  • the precursor of the cathode material prepared by the existing co-precipitation method has the problem of low first discharge capacity after being prepared into the cathode material, and the cycle performance also needs to be improved.
  • the present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a method for preparing a cathode material precursor.
  • the cathode material precursor prepared by the preparation method has excellent cycle performance and a high first discharge capacity after being prepared into a cathode material.
  • a cathode material precursor which is prepared by a co-precipitation reaction, and the pH of the system is controlled to be 9-12 during the co-precipitation reaction.
  • the co-precipitation reaction reaches equilibrium, any distance
  • the deformation stacking fault rate f D of the crystals in the system is 1%-10%.
  • a method for preparing the precursor of the cathode material as described above including the following steps: (1) Mixing and reacting a metal salt solution containing nickel, cobalt and manganese, a precipitant, a complexing agent and an alkaline bottom liquid to obtain a mixed liquid.
  • the reaction process The pH of the control system is 9-12.
  • the pH of the system is adjusted to control the balance of the co-precipitation reaction.
  • the adjustment of the pH refers to Adjust the pH up to 0.02-0.04 or down to 0.03-0.06; (2) Separate the mixed liquid obtained in step (1) from solid to liquid to obtain a solid, which is washed and dried to obtain the positive electrode material precursor.
  • the pH is continuously adjusted.
  • adjusting the pH means raising the pH of the system by 0.02-0.04 when the D50 of the precursor crystal is greater than the target particle size by more than 0.3 ⁇ m; When D50 is more than 0.3 ⁇ m smaller than the target particle size, lower the pH of the system by 0.03-0.06.
  • the total concentration of nickel, cobalt and manganese metal ions in the nickel, cobalt and manganese-containing metal salt solution is 1-3 mol/L.
  • the precipitating agent is at least one of sodium hydroxide solution and potassium hydroxide solution, and the concentration of the precipitating agent is 2-14 mol/L.
  • the complexing agent is ammonia water with a mass fraction of 20%.
  • the alkaline bottom liquid is a mixed liquid of sodium hydroxide and ammonia water
  • the pH of the alkaline bottom liquid is 9-12
  • the ammonia water concentration in the alkaline bottom liquid is 0. -10g/L.
  • step (1) the reaction is carried out in a reaction kettle, and the mixing method is to add the nickel-cobalt-manganese-containing metal salt solution, the precipitant and the complexing agent in parallel streams. into the alkaline bottom solution.
  • step (1) after the reaction reaches equilibrium, the difference in the deformation stacking fault rate f D of the crystals in the mixed solution is ⁇ 0.7% measured at any two periods 4 hours apart.
  • the reaction temperature of the reaction is 50-80°C.
  • the drying temperature is 90-120°C and the drying time is 30-50h.
  • a method for preparing a cathode material including the following steps: mixing the cathode material precursor, lithium source and additives as described above, sintering once in an oxygen atmosphere, crushing and then mixing with the additives, and then in the presence of oxygen Secondary sintering is performed under an atmosphere to prepare the positive electrode material.
  • the lithium source is at least one of LiOH and Li 2 CO 3 .
  • the additive contains at least one of Ni, Co, Mn, Zr, Al, Mg, Ti, Sr, W, Y, Mo, Sb, Nb, Sn, Zn, La, Ce, B and F elements.
  • the temperature of the primary sintering is 700-1020°C, and the sintering time is 28-32 hours.
  • the secondary sintering temperature is 250-750°C, and the sintering time is 6-9 hours.
  • a cathode material prepared by the above preparation method is a cathode material prepared by the above preparation method.
  • the chemical formula of the cathode material is Li 1+a Ni x Co y Mn z M b O 2 @N c , where 0 ⁇ a ⁇ 0.2, 0 ⁇ b ⁇ 0.03, 0 ⁇ c ⁇ 0.04, M, N It is at least one of Ni, Co, Mn, Zr, Al, Mg, Ti, Sr, W, Y, Mo, Sb, Nb, Sn, Zn, La, Ce, B and F elements.
  • the pH of the synthetic precursor is controlled at 9-12, and the pH is continuously adjusted after the particle size reaches the target particle size.
  • the balance of co-precipitation reaction and complexation reaction is controlled, and the growth rate of crystals is adjusted. If the crystal grows quickly, the probability of forming defects is high, while if the crystal grows slowly, it is beneficial to obtain an ideal crystal without defects.
  • the growth rate of the crystal in different periods of time is changed, thereby obtaining a precursor with a gradient defect structure.
  • the structural defects of the precursor are represented by the growth stacking fault rate f D , which can be obtained through the XRD pattern of the precursor.
  • the gradient defect structure is inherited in the cathode material.
  • the gradient defect structure can also release the stress generated during the deintercalation process of lithium ions. This reduces the cracking of primary particles and secondary agglomerates and improves the cycle performance of the cathode material.
  • the gradient defects mentioned above are at the atomic scale within the material, and the gradient defects will not introduce new interfaces or add new interfaces. Impedance, thereby improving the electrochemical properties of the material;
  • the system is under a high pH value, causing the balance of precipitation reaction and complexation reaction to be broken, the precipitation reaction is enhanced, and more small particles are produced in a short period of time, resulting in a broadening of the particle size distribution of the precursor.
  • a wide particle size distribution can effectively increase the particle size.
  • the packing density of the cathode material increases the energy density of the cathode material and the particle size distribution of the precursor.
  • span (D 90 -D 10 )/D 50 , the larger the span value, the broader the particle size distribution of the precursor; as the molten metal continues to be replenished, the supersaturation increases again, and then periodically Repeat the above reaction process.
  • Figure 1 is an SEM image of the process sample of the precursor prepared in Example 1 of the present invention with a reaction time of 80 hours;
  • Figure 2 is an SEM image of the process sample of the precursor prepared in Example 1 of the present invention with a reaction time of 84 hours;
  • Figure 3 is an SEM image of the cathode material prepared in Example 1 of the present invention.
  • Figure 4 is an SEM image of the process sample of the precursor prepared in Comparative Example 1 of the present invention with a reaction time of 80 hours;
  • Figure 5 is an SEM image of the process sample of the precursor prepared in Comparative Example 1 of the present invention with a reaction time of 84 hours;
  • Figure 6 is a comparison chart of the cycle capacity retention rates of the cathode materials prepared in Example 1 and Comparative Example 1 of the present invention.
  • Figure 7 is an X-ray diffraction pattern of the finished precursor prepared by the co-precipitation method in Example 1 and Comparative Example 1 of the present invention
  • Figure 8 is a particle size distribution diagram of the finished precursor prepared by the co-precipitation method in Example 1 and Comparative Example 1 of the present invention.
  • a method for preparing a cathode material precursor including the following steps:
  • nickel chloride, cobalt chloride and manganese chloride as raw materials to prepare nickel-containing nickel-cobalt-manganese metal ions with a total concentration of 2.0 mol/L
  • a sodium hydroxide solution with a concentration of 4.5 mol/L is prepared as a precipitating agent, and ammonia water with a mass fraction of 20% is prepared as a complexing agent;
  • Step 2 Add the alkaline bottom liquid into the reaction kettle until it covers the bottom stirring paddle, and start stirring.
  • the alkaline bottom liquid is a mixture of sodium hydroxide and ammonia water.
  • the pH value of the alkaline bottom liquid is 11.7, and the ammonia water concentration is 8.0. g/L;
  • Step 3 Add the nickel-cobalt-manganese-containing metal salt solution, sodium hydroxide solution and ammonia solution prepared in step 1 into the reaction kettle in parallel flow for reaction. Control the reaction temperature in the kettle to 65°C, pH to 11, and ammonia concentration to 8.0 g/L, using a continuous method to synthesize the precursor;
  • Step 4 Set the target particle size D50 of the precursor in the kettle to 4.0 ⁇ m.
  • the particle size D50 of the precursor in the kettle is detected to be 4.0 ⁇ 0.3 ⁇ m, adjust the reaction pH value. Specifically, when D50 is higher than the target particle size of 0.3 ⁇ m, increase the pH by 0.02; when D50 is lower than the target particle size of 0.3 ⁇ m, decrease the pH by 0.03 and continue to collect the material;
  • Step 5 Separate the collected materials from solid and liquid, and wash the precipitate
  • Step 6 Dry the precipitate at 120°C for 25 hours to obtain the cathode material precursor.
  • a cathode material precursor is prepared by the above preparation method.
  • the chemical formula of the cathode material precursor is Ni 0.70 Co 0.10 Mn 0.20 (OH) 2 .
  • a preparation method of cathode material including the following steps:
  • step (2) Coarsely crush and finely crush the primary-fired material obtained in step (1), then mix it evenly with the additives WO 3 and Al 2 O 3 , and conduct secondary sintering in an oxygen atmosphere to obtain a cathode material, in which WO 3
  • the addition amounts of Al 2 O 3 and Al 2 O 3 are 2000ppm and 1000ppm respectively (based on the weight of W and Al in WO 3 and Al 2 O 3 of the substrate).
  • the temperature of secondary sintering is 650°C, and the time of secondary sintering is 8 hours.
  • a cathode material is prepared by the above preparation method.
  • the chemical formula of the cathode material is Li(Ni 0.70 Co 0.10 Mn 0.20 ) 0.997 Zr 0.003 O 2 @W 0.00108 Al 0.00366 .
  • the SEM image of the cathode material is shown in Figure 3.
  • a method for preparing a cathode material precursor including the following steps:
  • Step 2 Add the alkaline bottom liquid into the reaction kettle until it covers the bottom stirring paddle, and start stirring.
  • the alkaline bottom liquid is a mixture of sodium hydroxide and ammonia water.
  • the pH value of the alkaline bottom liquid is 11.9, and the ammonia water concentration is 10g. /L;
  • Step 3 Add the nickel-cobalt-manganese-containing metal salt solution, sodium hydroxide solution and ammonia solution prepared in step 1 into the reaction kettle in parallel flow for reaction. Control the reaction temperature in the kettle to 60°C, the pH to 11.5, and the ammonia concentration to 10g. /L, using a continuous method to synthesize the precursor;
  • Step 4 Set the target particle size D50 of the precursor in the kettle to 4.2 ⁇ m.
  • the particle size D50 of the precursor in the kettle is detected to be 4.2 ⁇ 0.3 ⁇ m, adjust the reaction pH value. Specifically, when D50 is higher than the target particle size of 0.3 ⁇ m, increase the pH by 0.04; when D50 is lower than the target particle size of 0.3 ⁇ m, decrease the pH by 0.06 and continue to collect the material;
  • Step 5 Separate the collected materials from solid and liquid, and wash the precipitate
  • Step 6 Dry the precipitate at 115°C for 30 hours to obtain the cathode material precursor.
  • the growth stacking fault rates f D of the precursor obtained by fitting using X-pert Highscore software are 5.9% and 4.4% respectively.
  • the difference between f D measured twice is 1.5%, which is calculated based on the test results of laser particle size analyzer.
  • the spans are 1.11 and 1.40 respectively.
  • a cathode material precursor is prepared by the above preparation method.
  • the chemical formula of the cathode material precursor is Ni 0.65 Co 0.07 Mn 0.28 (OH) 2 .
  • a preparation method of cathode material including the following steps:
  • a sintering is performed in an oxygen atmosphere to obtain a sintered material, wherein the cathode material precursor and LiOH are mixed according to a molar ratio of Li/(Ni+Co+Mn) of 1.06, the addition amounts of ZrO2 and SrO are 2000ppm and 1500ppm respectively (based on the mass of Zr and Sr in ZrO2 and SrO to the precursor), the primary sintering temperature is 940°C, and the primary sintering time is 28h;
  • the primary-fired material obtained in step (1) is evenly mixed with the additives Sb 2 O 3 and TiO 2 , and is subjected to secondary sintering in an oxygen atmosphere to obtain a cathode material, in which Sb 2
  • the added amounts of O 3 and TiO 2 are 1500ppm and 2000ppm respectively (based on the weight of Sb and Ti in Sb 2 O 3 and TiO 2 of the substrate).
  • the temperature of secondary sintering is 550°C, and the time of secondary sintering is 6 hours.
  • a cathode material is prepared by the above preparation method.
  • the chemical formula of the cathode material is Li(Ni 0.65 Co 0.07 Mn 0.28 ) 0.997 Zr 0.002 Sr 0.001 O 2 @Sb 0.00122 Ti 0.00730 .
  • a method for preparing a cathode material precursor including the following steps:
  • nickel chloride, cobalt chloride and manganese chloride as raw materials to prepare nickel-containing nickel-cobalt-manganese metal ions with a total concentration of 1.5mol/L
  • a sodium hydroxide solution with a concentration of 10 mol/L is prepared as a precipitating agent, and ammonia water with a mass fraction of 20% is prepared as a complexing agent;
  • Step 2 Add the alkaline bottom liquid into the reaction kettle until it covers the bottom stirring paddle, and start stirring.
  • the alkaline bottom liquid is a mixture of sodium hydroxide and ammonia water.
  • the pH value of the alkaline bottom liquid is 10.7, and the ammonia water concentration is 4g. /L;
  • Step 3 Add the nickel-cobalt-manganese-containing metal salt solution, sodium hydroxide solution and ammonia solution prepared in step 1 into the reaction kettle in parallel flow for reaction. Control the reaction temperature in the kettle to 72°C, the pH to 10.7, and the ammonia concentration to 4g. /L, using a continuous method to synthesize the precursor;
  • Step 4 Set the target particle size D50 of the precursor in the kettle to 10 ⁇ m.
  • the particle size D50 of the precursor in the kettle is detected When it is 10 ⁇ 0.3 ⁇ m, adjust the reaction pH value. Specifically, when D50 is higher than the target particle size of 0.3 ⁇ m, increase the pH by 0.03; when D50 is lower than the target particle size of 0.3 ⁇ m, decrease the pH by 0.05 and continue to collect the material;
  • Step 5 Separate the collected materials from solid and liquid, and wash the precipitate
  • Step 6 Dry the precipitate at 90°C for 42 hours to obtain the cathode material precursor.
  • the growth stacking fault rates f D of the precursor obtained by fitting using X-pert Highscore software are 3.6% and 2.3% respectively.
  • the difference between f D measured twice is 1.3%, which is calculated based on the test results of laser particle size analyzer.
  • the spans are 1.21 and 1.45 respectively.
  • a cathode material precursor is prepared by the above preparation method.
  • the chemical formula of the cathode material precursor is Ni 0.80 Co 0.10 Mn 0.10 (OH) 2 .
  • a preparation method of cathode material including the following steps:
  • the primary-fired material obtained in step (1) is evenly mixed with the additives Nb 2 O 5 and CeO 2 , and is subjected to secondary sintering in an oxygen atmosphere to obtain a positive electrode material, in which Nb 2
  • the addition amounts of O 5 and CeO 2 are 1500ppm and 1500ppm respectively (calculated based on the weight of Nb and Ce in Nb 2 O 5 and CeO 2 of the substrate).
  • the temperature of secondary sintering is 420°C, and the time of secondary sintering is 7 hours.
  • a cathode material is prepared by the above preparation method.
  • the chemical formula of the cathode material is Li(Ni 0.80 Co 0.10 Mn 0.10 ) 0.997 Y 0.00156 La 0.00164 O 2 @Nb 0.00160 Ce 0.00552 .
  • a method for preparing a cathode material precursor including the following steps:
  • a sodium hydroxide solution with a concentration of 14.0 mol/L is prepared as a precipitating agent, and ammonia water with a mass fraction of 20% is used as a complexing agent;
  • Step 2 Add the alkaline bottom liquid into the reaction kettle until it covers the bottom stirring paddle, and start stirring.
  • the alkaline bottom liquid is a mixture of sodium hydroxide and ammonia water.
  • the pH value of the alkaline bottom liquid is 10.8, and the ammonia water concentration is 2g. /L;
  • Step 3 Add the metal salt solution containing nickel, cobalt and manganese, sodium hydroxide solution and ammonia solution prepared in step 1 in parallel flow. Go to the reaction kettle for the reaction, control the reaction temperature in the kettle to 50°C, the pH to 10, and the ammonia concentration to 2g/L, and use a continuous method to synthesize the precursor;
  • Step 4 Set the target particle size D50 of the precursor in the kettle to 8 ⁇ m.
  • the particle size D50 of the precursor in the kettle is detected to be 8 ⁇ 0.3 ⁇ m, adjust the reaction pH value. Specifically, when D50 is higher than the target particle size of 0.3 ⁇ m, increase the pH by 0.03; when D50 is lower than the target particle size of 0.3 ⁇ m, decrease the pH by 0.04 and continue to collect the material;
  • Step 5 Separate the collected materials from solid and liquid, and wash the precipitate
  • Step 6 Dry the precipitate at 100°C for 36 hours to obtain the cathode material precursor.
  • the growth stacking fault rates f D of the precursor obtained by fitting using X-pert Highscore software are 2.6% and 1.9% respectively.
  • the difference between f D measured twice is 0.7%, which is calculated based on the test results of laser particle size analyzer.
  • the spans are 1.09 and 1.48 respectively.
  • a cathode material precursor is prepared by the above preparation method.
  • the chemical formula of the cathode material precursor is Ni 0.95 Co 0.02 Mn 0.03 (OH) 2 .
  • a preparation method of cathode material including the following steps:
  • the molar ratio of (Ni+Co+Mn) is 1.01 for mixing, and the added amounts of MoO 3 and B 2 O 3 are 3000ppm and 800ppm respectively (based on the mass of the precursor occupied by Mo and B in MoO 3 and B 2 O 3 ),
  • the temperature of primary sintering is 832°C, and the time of primary sintering is 32h;
  • the first-burning material obtained in step (1) is evenly mixed with the additives MgCO 3 and LiF, and is subjected to secondary sintering in an oxygen atmosphere to obtain the cathode material, in which MgCO 3 and LiF
  • the addition amounts are 2000ppm and 1000ppm respectively (based on the weight of Mg and F in MgCO 3 and LiF of the substrate), the temperature of secondary sintering is 300°C, and the time of secondary sintering is 9 hours.
  • a cathode material is prepared by the above preparation method.
  • the chemical formula of the cathode material is Li(Ni 0.95 Co 0.02 Mn 0.03 ) 0.997 Mo 0.00289 La 0.00053 O 2 @Mg 0.00817 F 0.00368 .
  • a method for preparing a cathode material precursor including the following steps:
  • nickel chloride, cobalt chloride and manganese chloride as raw materials to prepare nickel-containing nickel-cobalt-manganese metal ions with a total concentration of 2.0 mol/L
  • a sodium hydroxide solution with a concentration of 4.5 mol/L is prepared as a precipitating agent, and ammonia water with a mass fraction of 20% is prepared as a complexing agent;
  • Step 2 Add the alkaline bottom liquid into the reaction kettle until it covers the bottom stirring paddle, and start stirring.
  • the alkaline bottom liquid is a mixture of sodium hydroxide and ammonia water.
  • the pH value of the alkaline bottom liquid is 10.6, and the ammonia water concentration is 4g. /L;
  • Step 3 Add the nickel-cobalt-manganese-containing metal salt solution, sodium hydroxide solution and ammonia solution prepared in step 1 into the reaction kettle in parallel flow for reaction. Control the reaction temperature in the kettle to 65°C, the pH to 9.8, and the ammonia concentration to 4g. /L, using a continuous method to synthesize the precursor;
  • Step 4 Set the target particle size D50 of the precursor in the kettle to 4.0 ⁇ m.
  • the particle size D50 of the precursor in the kettle is detected to be 4.0 ⁇ 0.3 ⁇ m, adjust the reaction pH value. Specifically, when D50 is higher than the target particle size of 0.3 ⁇ m, increase the pH by 0.02; when D50 is lower than the target particle size of 0.3 ⁇ m, decrease the pH by 0.03 and continue to collect the material;
  • Step 5 Separate the collected materials from solid and liquid, and wash the precipitate
  • Step 6 Dry the precipitate at 120°C for 25 hours to obtain the cathode material precursor.
  • a cathode material precursor is prepared by the above preparation method.
  • the chemical formula of the cathode material precursor is Ni 0.70 Co 0.10 Mn 0.20 (OH) 2 .
  • a preparation method of cathode material including the following steps:
  • step (2) Coarsely crush and finely crush the primary-fired material obtained in step (1), then mix it evenly with the additives WO 3 and Al 2 O 3 , and conduct secondary sintering in an oxygen atmosphere to obtain a cathode material, in which WO 3
  • the addition amounts of Al 2 O 3 and Al 2 O 3 are 2000ppm and 1000ppm respectively (based on the weight of W and Al in WO 3 and Al 2 O 3 of the substrate).
  • the temperature of secondary sintering is 650°C, and the time of secondary sintering is 8 hours.
  • a cathode material is prepared by the above preparation method.
  • the chemical formula of the cathode material is Li(Ni 0.70 Co 0.10 Mn 0.20 ) 0.997 Zr 0.003 O 2 @W 0.00108 Al 0.00366 .
  • a method for preparing a cathode material precursor including the following steps:
  • For salt solution prepare a sodium hydroxide solution with a concentration of 14 mol/L as a precipitant, and prepare ammonia water with a mass fraction of 20% as a complexing agent;
  • Step 2 Add the alkaline bottom liquid into the reaction kettle until it covers the bottom stirring paddle, and start stirring.
  • the alkaline bottom liquid is a mixture of sodium hydroxide and ammonia water.
  • the pH value of the alkaline bottom liquid is 10, and the ammonia water concentration is 1g. /L;
  • Step 3 Add the nickel-cobalt-manganese-containing metal salt solution, sodium hydroxide solution and ammonia solution prepared in step 1 into the reaction kettle in parallel flow for reaction. Control the reaction temperature in the kettle to 50°C, the pH to 9.2, and the ammonia concentration to 1g. /L, using a continuous method to synthesize the precursor;
  • Step 4 Set the target particle size D50 of the precursor in the kettle to 8 ⁇ m.
  • the particle size D50 of the precursor in the kettle is detected to be 8 ⁇ 0.3 ⁇ m, adjust the reaction pH value. Specifically, when D50 is higher than the target particle size of 0.3 ⁇ m, increase the pH by 0.03; when D50 is lower than the target particle size of 0.3 ⁇ m, decrease the pH by 0.04 and continue to collect the material;
  • Step 5 Separate the collected materials from solid and liquid, and wash the precipitate
  • Step 6 Dry the precipitate at 100°C for 36 hours to obtain the cathode material precursor.
  • the growth stacking fault rates f D of the precursor obtained by fitting using X-pert Highscore software are 0.83% and 0.74% respectively.
  • the difference between f D measured twice is 0.09%, which is calculated based on the test results of laser particle size analyzer.
  • the spans are 1.08 and 1.03 respectively.
  • a cathode material precursor is prepared by the above preparation method.
  • the chemical formula of the cathode material precursor is Ni 0.95 Co 0.02 Mn 0.03 (OH) 2 .
  • a preparation method of cathode material including the following steps:
  • the molar ratio of (Ni+Co+Mn) is 1.01 for mixing, and the added amounts of MoO 3 and B 2 O 3 are 3000ppm and 800ppm respectively (based on the mass of the precursor occupied by Mo and B in MoO 3 and B 2 O 3 ),
  • the temperature of primary sintering is 832°C, and the temperature of primary sintering is 32h;
  • the first-burning material obtained in step (1) is evenly mixed with the additives MgCO 3 and LiF, and is subjected to secondary sintering in an oxygen atmosphere to obtain the cathode material, in which MgCO 3 and LiF
  • the addition amounts are 2000ppm and 1000ppm respectively (based on the weight of Mg and F in MgCO 3 and LiF of the substrate).
  • the temperature of secondary sintering is 300°C and the temperature of secondary sintering is 9h.
  • a cathode material is prepared by the above preparation method.
  • the chemical formula of the cathode material is Li(Ni 0.95 Co 0.02 Mn 0.03 ) 0.997 Mo 0.00289 La 0.00053 O 2 @Mg 0.00817 F 0.00368 .
  • the cathode materials of Examples 1-4 and Comparative Examples 1-2 were respectively formulated into button batteries for electrochemical performance testing of lithium ion batteries.
  • the specific steps were: using N-methylpyrrolidone as the solvent, according to the mass ratio of 8:1
  • the battery was assembled in an argon-protected glove box.
  • the cathode was a lithium metal sheet, the separator was a polypropylene film, and the electrolyte was 1M LiPF6-EC/DMC (1:1, v/v).
  • Theoretical research has confirmed that the ratio of I (101) and I (001) peak intensity is related to the defects in the precursor.
  • the particle size distribution diagram of the finished precursor prepared by the co-precipitation method in Example 1 and Comparative Example 1 of the present invention is shown in Figure 8.
  • Example 1 and Comparative Example 1 are consistent with the characteristics of a normal distribution, but the particle size distribution of the corresponding precursor in Example 1 is "short and fat", indicating that its particle size distribution is wider, while for In proportion 1, the particle size distribution of the precursor is relatively concentrated, and the performance of the particle size distribution of the precursor and the mechanism of process adjustment in the embodiment are mutually confirmed.
  • the cathode material precursor prepared by the preparation method of the present invention has excellent electrochemical properties after being prepared into the cathode material. Its 0.1C discharge capacity can reach more than 192mAh/g, and the first efficiency can reach more than 90.8%. The cycle capacity retention rate after the cycle can reach more than 90.1%.

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Abstract

本发明公开了一种正极材料前驱体，所述正极材料前驱体由共沉淀反应制备得到，且在所述共沉淀反应过程中控制体系的pH为9-12，当所述共沉淀反应达到平衡后，任意相隔4h的两个时段测得体系中晶体的形变层错率fD的差值≥0.7％，所述形变层错率fD＝0.19FWHM(101)–0.055FWHM(102)–0.5/D(001)，其中，FWHM(101)为(101)衍射峰的半峰宽，FWHM(102)为(102)衍射峰的半峰宽，D(001)为(001)晶面对应的晶粒尺寸。该正极材料前驱体在制备成正极材料后，具有优异的循环性能，同时首次放电容量也较高。

Description

一种正极材料前驱体、正极材料及其制备方法和应用 技术领域
本发明属于锂离子电池正极材料技术领域，特别涉及一种正极材料前驱体、正极材料及其制备方法和应用。
背景技术
当今“碳中和”、“碳达峰”的双碳背景下，传统的产业能源结构面临新一轮的调整。其中，锂电池产业经过数年的发展已然成为新能源行业的中流砥柱。其中高性能正极材料无疑是整个上下游产业链中的皇冠，而正极材料的性能60％-70％取决于前驱体，高性能前驱体无疑是皇冠上最璀璨夺目的明珠。
目前，制备锂离子电池正极材料的前驱体通常采用共沉淀法制备，过程中主要通过沉淀反应和络合反应来控制晶体的成核和生长。但现有的共沉淀法制备得到的正极材料的前驱体在制备成正极材料后，存在首次放电容量低，同时循环性能也有待提高的问题。
发明内容
本发明旨在至少解决现有技术中存在的技术问题之一。为此，本发明提出一种正极材料前驱体的制备方法，该制备方法制备得到的正极材料的前驱体在制备成正极材料后，具有优异的循环性能，同时首次放电容量也较高。
本发明的上述技术目的是通过以下技术方案得以实现的：
一种正极材料前驱体，所述正极材料前驱体由共沉淀反应制备得到，且在所述共沉淀反应过程中控制体系的pH为9-12，当所述共沉淀反应达到平衡后，任意相隔4h的两个时段测得体系中晶体的形变层错率fD的差值≥0.7％，所述形变层错率fD＝0.19FWHM(101)–0.055FWHM(102)–0.5/D(001)，其中，FWHM(101)为(101)衍射峰的半峰宽，FWHM(102)为(102)衍射峰的半峰宽，D(001)为(001)晶面对应的晶粒尺寸。
优选的，当所述共沉淀反应达到平衡后，所述体系中晶体的形变层错率fD为1％-10％。
优选的，所述正极材料前驱体的粒度分布span值≥1.30，其中，span＝(D90-D10)/D50。
优选的，所述正极材料前驱体的化学式为NixCoyMnz(OH)2；其中0≤x≤1；0≤y≤0.9；0≤z≤0.9且x+y+z＝1。
一种如上所述正极材料前驱体的制备方法，包括以下步骤：(1)将含镍钴锰的金属盐溶液、沉淀剂、络合剂和碱性底液混合反应，得到混合液，反应过程中控制体系的pH为9-12，当所述反应得到的前驱体晶体的粒度D50达到1-15μm后对体系的pH进行调整，以控制共沉淀反应平衡，所述对pH进行调整是指将pH上调0.02-0.04或将pH下调0.03-0.06；(2)将步骤(1)得到的混合液固液分离，得到固体物，洗涤后，烘干，得到所述正极材料前驱体。
进一步优选的，当所述反应得到的前驱体晶体的粒度D50达到4-10μm后持续对pH进行调整。
优选的，步骤(1)中，所述对pH进行调整是指当所述前驱体晶体的D50比目标粒度大0.3μm以上时，将体系的pH上调0.02-0.04；当所述前驱体晶体的D50比目标粒度小0.3μm以上时，将体系的pH下调0.03-0.06。
优选的，步骤(1)中，所述含镍钴锰的金属盐溶液中镍钴锰金属离子总浓度为1-3mol/L。
优选的，步骤(1)中，所述含镍钴锰的金属盐溶液中镍元素、钴元素及锰元素的摩尔比为x:y:z，其中，0≤x≤1；0≤y≤0.9；0≤z≤0.9且x+y+z＝1。
优选的，步骤(1)中，所述沉淀剂为氢氧化钠溶液及氢氧化钾溶液中的至少一种，所述沉淀剂的浓度为2-14mol/L。
优选的，步骤(1)中，所述络合剂为质量分数为20％的氨水。
优选的，步骤(1)中，所述碱性底液为氢氧化钠和氨水的混合液，所述碱性底液的pH为9-12，所述碱性底液中的氨水浓度为0-10g/L。
优选的，步骤(1)中，所述反应是在反应釜中进行，所述混合的方式为将所述含镍钴锰的金属盐溶液、所述沉淀剂及所述络合剂并流加入到所述碱性底液中。
优选的，步骤(1)中，当所述反应达到平衡后，任意相隔4h的两个时段测得所述混合液中晶体的形变层错率fD的差值≥0.7％。
优选的，步骤(1)中，所述反应的反应温度为50-80℃。
优选的，步骤(2)中，所述烘干的烘干温度为90-120℃，烘干时间为30-50h。
一种正极材料的制备方法，包括以下步骤：将如上所述的正极材料前驱体、锂源和添加剂混合，在有氧气氛下进行一次烧结，破碎后再与添加剂混合，在有氧 气氛下进行二次烧结，制得所述正极材料。
优选的，所述锂源为LiOH及Li2CO3中的至少一种。
优选的，所述添加剂为含有Ni、Co、Mn、Zr、Al、Mg、Ti、Sr、W、Y、Mo、Sb、Nb、Sn、Zn、La、Ce、B及F元素中的至少一种元素的化合物或化合物的组合。
优选的，所述一次烧结的温度为700-1020℃，烧结时间为28-32h。
优选的，所述二次烧结的温度为250-750℃，烧结时间为6-9h。
一种正极材料，由如上所述的制备方法制备得到。
优选的，所述正极材料的化学式为Li1+aNixCoyMnzMbO2@Nc，其中0≤a≤0.2，0≤b≤0.03，0≤c≤0.04，M，N为Ni、Co、Mn、Zr、Al、Mg、Ti、Sr、W、Y、Mo、Sb、Nb、Sn、Zn、La、Ce、B及F元素中的至少一种。
如上所述的正极材料在制备锂离子电池中的应用。
本发明的有益效果是：
(1)本发明正极材料前驱体在制备过程中，将合成前驱体的pH控制在9-12，并在粒度达到目标粒度后持续对pH进行调整。通过对pH的持续调节，控制共沉淀反应与络合反应的平衡，调节晶体的生长速度。晶体生长快则形成缺陷的几率高，晶体生长缓慢则有利于获得无缺陷的理想晶体。通过对反应体系pH的持续变化，改变晶体在不同时段的生长速度，从而获得具有梯度缺陷结构的前驱体，前驱体的结构缺陷用生长层错率fD表示，可通过对前驱体的XRD图谱用X-pert Highscore软件拟合计算得出，上述前驱体经过高温锂化烧结后，梯度缺陷结构在正极材料中得以继承，梯度缺陷结构还能够起到释放锂离子脱嵌过程中产生的应力，从而减轻了一次粒子和二次团聚体的开裂，提升正极材料的循环性能，此外，以上所述的梯度缺陷是材料内部原子尺度的，梯度缺陷不会引入新的界面，不会增加新的界面阻抗，从而改善材料的电化学性能；
(2)本发明正极材料前驱体在制备过程中，由于反应体系处于高pH值下容易获得高过饱和度(过饱和度S＝[Me2+][OH-]2/Kθ sp,Me(OH)2)，而晶体的成核和生长的驱动力均为过饱和度，高过饱和度下晶体的成核和生长处于较高的速度下，导致过饱和度消耗过快；由于反应体系处于高pH值下，导致沉淀反应和络合反应的平衡被打破，沉淀反应增强，短时间内产生较多的小颗粒，导致前驱体的粒度分布变宽，宽粒度分布则能有效提高颗粒间的堆积密度，从而提高正极材料的能量密度，前驱体的粒度分布 用span值表示，span＝(D90-D10)/D50，span值越大，表明前驱体的粒度分布越宽泛；随着金属液持续补充，过饱和度再次升高，进而周期性地重复上述反应过程。
附图说明
图1为本发明实施例1中制备的反应时间为80h的前驱体过程样的SEM图；
图2为本发明实施例1中制备的反应时间为84h的前驱体过程样的SEM图；
图3为本发明实施例1中制备的正极材料的SEM图；
图4为本发明对比例1中制备的反应时间为80h的前驱体过程样的SEM图；
图5为本发明对比例1中制备的反应时间为84h的前驱体过程样的SEM图；
图6为本发明实施例1和对比例1制备的正极材料的循环容量保持率对比图；
图7为本发明实施例1和对比例1中共沉淀法制备的前驱体成品的X射线衍射图；
图8为本发明实施例1和对比例1中共沉淀法制备的前驱体成品的粒度分布图。
具体实施方式
下面结合具体实施例对本发明做进一步的说明。
实施例1：
一种正极材料前驱体的制备方法，包括以下步骤：
步骤1.按照元素摩尔比Ni:Co:Mn＝0.70:0.10:0.20，选用氯化镍、氯化钴及氯化锰为原料，配制镍钴锰金属离子总浓度为2.0mol/L的含镍钴锰的金属盐溶液，配制浓度为4.5mol/L的氢氧化钠溶液作为沉淀剂，配制质量分数为20％的氨水作为络合剂；
步骤2.向反应釜中加入碱性底液至漫过底层搅拌桨，启动搅拌，碱性底液为氢氧化钠和氨水的混合液，碱性底液的pH值为11.7，氨水浓度为8.0g/L；
步骤3.将步骤1配制的含镍钴锰的金属盐溶液、氢氧化钠溶液以及氨水并流加入到反应釜中进行反应，控制釜内反应温度为65℃，pH为11，氨水浓度为8.0g/L，采用连续法合成前驱体；
步骤4.设置釜内前驱体的目标粒度D50为4.0μm，当检测到釜内前驱体的粒度D50为4.0±0.3μm时，调整反应pH值。具体为当D50高于目标粒度0.3μm，上调pH 0.02；当D50低于目标粒度0.3μm，下调pH 0.03，并持续收料；
步骤5.将收集的物料进行固液分离，洗涤沉淀物；
步骤6.将沉淀物在120℃下烘干25h，得到正极材料前驱体。
分别取反应进行到第80h、84h的过程样测试(4h远低于前驱体颗粒在反应釜内的停留时间τ，仅有少量二次颗粒从溢流口排出，因此可视为釜内物料大致为同一批物料)， 前驱体的形貌如图1、图2所示。采用X-pert Highscore软件拟合得出的前驱体的生长层错率fD分别为4.7％和3.3％，两次测得的fD的差值为1.4％，基于激光粒度仪测试结果计算出的span分别为1.21和1.37。
一种正极材料前驱体，由上述制备方法制备得到，正极材料前驱体的化学式为Ni0.70Co0.10Mn0.20(OH)2。
一种正极材料的制备方法，包括以下步骤：
(1)将如上所述的正极材料前驱体与LiOH、添加剂ZrO2混合均匀后，在有氧气氛下进行一次烧结得到一烧物料，其中正极材料前驱体与LiOH按照Li/(Ni+Co+Mn)的摩尔比为1.05进行混合，ZrO2的添加量为3000ppm(以ZrO2中Zr占前驱体质量计)，一次烧结的温度为925℃，一次烧结的时间为30h；
(2)将步骤(1)得到的一烧物料经过粗破碎、细破碎后再与添加剂WO3和Al2O3混合均匀，在有氧气氛下进行二次烧结，得到正极材料，其中WO3和Al2O3的添加量分别为2000ppm和1000ppm(以WO3和Al2O3中W和Al占基材重量计)，二次烧结的温度为650℃，二次烧结的时间为8h。
一种正极材料，由上述制备方法制备得到，正极材料的化学式为Li(Ni0.70Co0.10Mn0.20)0.997Zr0.003O2@W0.00108Al0.00366，正极材料的SEM图如图3所示。
实施例2：
一种正极材料前驱体的制备方法，包括以下步骤：
步骤1.按照元素摩尔比Ni:Co:Mn＝0.65:0.07:0.28，选用氯化镍、氯化钴及氯化锰为原料，配制镍钴锰金属离子总浓度为2.5mol/L的含镍钴锰的金属盐溶液，配制浓度为5.5mol/L的氢氧化钠溶液作为沉淀剂，配制质量分数为20％的氨水作为络合剂；
步骤2.向反应釜中加入碱性底液至漫过底层搅拌桨，启动搅拌，碱性底液为氢氧化钠和氨水的混合液，碱性底液的pH值为11.9，氨水浓度为10g/L；
步骤3.将步骤1配制的含镍钴锰的金属盐溶液、氢氧化钠溶液以及氨水并流加入到反应釜中进行反应，控制釜内反应温度为60℃，pH为11.5，氨水浓度为10g/L，采用连续法合成前驱体；
步骤4.设置釜内前驱体的目标粒度D50为4.2μm，当检测到釜内前驱体的粒度D50为4.2±0.3μm时，调整反应pH值。具体为当D50高于目标粒度0.3μm，上调pH 0.04；当D50低于目标粒度0.3μm，下调pH 0.06，并持续收料；
步骤5.将收集的物料进行固液分离，洗涤沉淀物；
步骤6.将沉淀物在115℃下烘干30h，得到正极材料前驱体。
分别取反应进行到第80h、84h的过程样测试(4h远低于前驱体颗粒在反应釜内的停留时间τ，仅有少量二次颗粒从溢流口排出，因此可视为釜内物料大致为同一批物料)。采用X-pert Highscore软件拟合得出的前驱体的生长层错率fD分别为5.9％和4.4％，两次测得的fD的差值为1.5％，基于激光粒度仪测试结果计算出的span分别为1.11和1.40。
一种正极材料前驱体，由上述制备方法制备得到，正极材料前驱体的化学式为Ni0.65Co0.07Mn0.28(OH)2。
一种正极材料的制备方法，包括以下步骤：
(1)将如上所述的正极材料前驱体与LiOH、添加剂ZrO2和SrO混合均匀后，在有氧气氛下进行一次烧结得到一烧物料，其中正极材料前驱体与LiOH按照Li/(Ni+Co+Mn)的摩尔比为1.06进行混合，ZrO2和SrO的添加量分别为2000ppm和1500ppm(以ZrO2和SrO中Zr和Sr占前驱体质量计)，一次烧结的温度为940℃，一次烧结的时间为28h；
(2)将步骤(1)得到的一烧物料经过粗破碎、细破碎后再与添加剂Sb2O3和TiO2混合均匀，在有氧气氛下进行二次烧结，得到正极材料，其中Sb2O3和TiO2的添加量分别为1500ppm和2000ppm(以Sb2O3和TiO2中Sb和Ti占基材重量计)，二次烧结的温度为550℃，二次烧结的时间为6h。
一种正极材料，由上述制备方法制备得到，正极材料的化学式为Li(Ni0.65Co0.07Mn0.28)0.997Zr0.002Sr0.001O2@Sb0.00122Ti0.00730。
实施例3：
一种正极材料前驱体的制备方法，包括以下步骤：
步骤1.按照元素摩尔比Ni:Co:Mn＝0.80:0.10:0.10，选用氯化镍、氯化钴及氯化锰为原料，配制镍钴锰金属离子总浓度为1.5mol/L的含镍钴锰的金属盐溶液，配制浓度为10mol/L的氢氧化钠溶液作为沉淀剂，配制质量分数为20％的氨水作为络合剂；
步骤2.向反应釜中加入碱性底液至漫过底层搅拌桨，启动搅拌，碱性底液为氢氧化钠和氨水的混合液，碱性底液的pH值为10.7，氨水浓度为4g/L；
步骤3.将步骤1配制的含镍钴锰的金属盐溶液、氢氧化钠溶液以及氨水并流加入到反应釜中进行反应，控制釜内反应温度为72℃，pH为10.7，氨水浓度为4g/L，采用连续法合成前驱体；
步骤4.设置釜内前驱体的目标粒度D50为10μm，当检测到釜内前驱体的粒度D50 为10±0.3μm时，调整反应pH值。具体为当D50高于目标粒度0.3μm，上调pH 0.03；当D50低于目标粒度0.3μm，下调pH 0.05，并持续收料；
步骤5.将收集的物料进行固液分离，洗涤沉淀物；
步骤6.将沉淀物在90℃下烘干42h，得到正极材料前驱体。
分别取反应进行到第80h、84h的过程样测试(4h远低于前驱体颗粒在反应釜内的停留时间τ，仅有少量二次颗粒从溢流口排出，因此可视为釜内物料大致为同一批物料)。采用X-pert Highscore软件拟合得出的前驱体的生长层错率fD分别为3.6％和2.3％，两次测得的fD的差值为1.3％，基于激光粒度仪测试结果计算出的span分别为1.21和1.45。
一种正极材料前驱体，由上述制备方法制备得到，正极材料前驱体的化学式为Ni0.80Co0.10Mn0.10(OH)2。
一种正极材料的制备方法，包括以下步骤：
(1)将如上所述的正极材料前驱体与LiOH、添加剂Y2O3和La2O3混合均匀后，在有氧气氛下进行一次烧结得到一烧物料，其中正极材料前驱体与LiOH按照Li/(Ni+Co+Mn)的摩尔比为1.02进行混合，Y2O3和La2O3的添加量分别为1500ppm和2500ppm(以Y2O3和La2O3中Y和La占前驱体质量计)，一次烧结的温度为875℃，一次烧结的时间为32h；
(2)将步骤(1)得到的一烧物料经过粗破碎、细破碎后再与添加剂Nb2O5和CeO2混合均匀，在有氧气氛下进行二次烧结，得到正极材料，其中Nb2O5和CeO2的添加量分别为1500ppm和1500ppm(以Nb2O5和CeO2中Nb和Ce占基材重量计)，二次烧结的温度为420℃，二次烧结的时间为7h。
一种正极材料，由上述制备方法制备得到，正极材料的化学式为Li(Ni0.80Co0.10Mn0.10)0.997Y0.00156La0.00164O2@Nb0.00160Ce0.00552。
实施例4：
一种正极材料前驱体的制备方法，包括以下步骤：
步骤1.按照元素摩尔比Ni:Co:Mn＝0.95:0.02:0.03，选用硫酸镍、硫酸钴及硫酸锰为原料，配制镍钴锰金属离子总浓度为2mol/L的含镍钴锰的金属盐溶液，配制浓度为14.0mol/L的氢氧化钠溶液作为沉淀剂，配制质量分数为20％氨水作为络合剂；
步骤2.向反应釜中加入碱性底液至漫过底层搅拌桨，启动搅拌，碱性底液为氢氧化钠和氨水的混合液，碱性底液的pH值为10.8，氨水浓度为2g/L；
步骤3.将步骤1配制的含镍钴锰的金属盐溶液、氢氧化钠溶液以及氨水并流加入 到反应釜中进行反应，控制釜内反应温度为50℃，pH为10，氨水浓度为2g/L，采用连续法合成前驱体；
步骤4.设置釜内前驱体的目标粒度D50为8μm，当检测到釜内前驱体的粒度D50为8±0.3μm时，调整反应pH值。具体为当D50高于目标粒度0.3μm，上调pH 0.03；当D50低于目标粒度0.3μm，下调pH 0.04，并持续收料；
步骤5.将收集的物料进行固液分离，洗涤沉淀物；
步骤6.将沉淀物在100℃下烘干36h，得到正极材料前驱体。
分别取反应进行到第80h、84h的过程样测试(4h远低于前驱体颗粒在反应釜内的停留时间τ，仅有少量二次颗粒从溢流口排出，因此可视为釜内物料大致为同一批物料)。采用X-pert Highscore软件拟合得出的前驱体的生长层错率fD分别为2.6％和1.9％，两次测得的fD的差值为0.7％，基于激光粒度仪测试结果计算出的span分别为1.09和1.48。
一种正极材料前驱体，由上述制备方法制备得到，正极材料前驱体的化学式为Ni0.95Co0.02Mn0.03(OH)2。
一种正极材料的制备方法，包括以下步骤：
(1)将如上所述的正极材料前驱体与LiOH、添加剂MoO3和B2O3混合均匀后，在有氧气氛下进行一次烧结得到一烧物料，其中正极材料前驱体与LiOH按照Li/(Ni+Co+Mn)的摩尔比为1.01进行混合，MoO3和B2O3的添加量分别为3000ppm和800ppm(以MoO3和B2O3中Mo和B占前驱体质量计)，一次烧结的温度为832℃，一次烧结的时间为32h；
(2)将步骤(1)得到的一烧物料经过粗破碎、细破碎后再与添加剂MgCO3和LiF混合均匀，在有氧气氛下进行二次烧结，得到正极材料，其中MgCO3和LiF的添加量分别为2000ppm和1000ppm(以MgCO3和LiF中Mg和F占基材重量计)，二次烧结的温度为300℃，二次烧结的时间为9h。
一种正极材料，由上述制备方法制备得到，正极材料的化学式为Li(Ni0.95Co0.02Mn0.03)0.997Mo0.00289La0.00053O2@Mg0.00817F0.00368。
对比例1：
一种正极材料前驱体的制备方法，包括以下步骤：
步骤1.按照元素摩尔比Ni:Co:Mn＝0.70:0.10:0.20，选用氯化镍、氯化钴及氯化锰为原料，配制镍钴锰金属离子总浓度为2.0mol/L的含镍钴锰的金属盐溶液，配制浓度为4.5mol/L的氢氧化钠溶液作为沉淀剂，配制质量分数为20％的氨水作为络合剂；
步骤2.向反应釜中加入碱性底液至漫过底层搅拌桨，启动搅拌，碱性底液为氢氧化钠和氨水的混合液，碱性底液的pH值为10.6，氨水浓度为4g/L；
步骤3.将步骤1配制的含镍钴锰的金属盐溶液、氢氧化钠溶液以及氨水并流加入到反应釜中进行反应，控制釜内反应温度为65℃，pH为9.8，氨水浓度为4g/L，采用连续法合成前驱体；
步骤4.设置釜内前驱体的目标粒度D50为4.0μm，当检测到釜内前驱体的粒度D50为4.0±0.3μm时，调整反应pH值。具体为当D50高于目标粒度0.3μm，上调pH 0.02；当D50低于目标粒度0.3μm，下调pH 0.03，并持续收料；
步骤5.将收集的物料进行固液分离，洗涤沉淀物；
步骤6.将沉淀物在120℃下烘干25h，得到正极材料前驱体。
分别取反应进行到第80h、84h的过程样测试(4h远低于前驱体颗粒在反应釜内的停留时间τ，仅有少量二次颗粒从溢流口排出，因此可视为釜内物料大致为同一批物料)，前驱体的形貌如图4、图5所示。采用X-pert Highscore软件拟合得出的前驱体的生长层错率fD分别为3.6％和3.8％，两次测得的fD的差值为0.2％，基于激光粒度仪测试结果计算出的span分别为1.12和1.11。
一种正极材料前驱体，由上述制备方法制备得到，正极材料前驱体的化学式为Ni0.70Co0.10Mn0.20(OH)2。
一种正极材料的制备方法，包括以下步骤：
(1)将如上所述的正极材料前驱体与LiOH、添加剂ZrO2混合均匀后，在有氧气氛下进行一次烧结得到一烧物料，其中正极材料前驱体与LiOH按照Li/(Ni+Co+Mn)的摩尔比为1.05进行混合，ZrO2的添加量为3000ppm(以ZrO2中Zr占前驱体质量计)，一次烧结的温度为925℃，一次烧结的时间为30h；
(2)将步骤(1)得到的一烧物料经过粗破碎、细破碎后再与添加剂WO3和Al2O3混合均匀，在有氧气氛下进行二次烧结，得到正极材料，其中WO3和Al2O3的添加量分别为2000ppm和1000ppm(以WO3和Al2O3中W和Al占基材重量计)，二次烧结的温度为650℃，二次烧结的时间为8h。
一种正极材料，由上述制备方法制备得到，正极材料的化学式为Li(Ni0.70Co0.10Mn0.20)0.997Zr0.003O2@W0.00108Al0.00366。
对比例2：
一种正极材料前驱体的制备方法，包括以下步骤：
步骤1.按照元素摩尔比Ni:Co:Mn＝0.95:0.02:0.03，选用硫酸镍、硫酸钴及硫酸锰为原料，配制镍钴锰金属离子总浓度为2mol/L的含镍钴锰的金属盐溶液，配制浓度为14mol/L的氢氧化钠溶液作为沉淀剂，配制质量分数为20％的氨水作为络合剂；
步骤2.向反应釜中加入碱性底液至漫过底层搅拌桨，启动搅拌，碱性底液为氢氧化钠和氨水的混合液，碱性底液的pH值为10，氨水浓度为1g/L；
步骤3.将步骤1配制的含镍钴锰的金属盐溶液、氢氧化钠溶液以及氨水并流加入到反应釜中进行反应，控制釜内反应温度为50℃，pH为9.2，氨水浓度为1g/L，采用连续法合成前驱体；
步骤4.设置釜内前驱体的目标粒度D50为8μm，当检测到釜内前驱体的粒度D50为8±0.3μm时，调整反应pH值。具体为当D50高于目标粒度0.3μm，上调pH 0.03；当D50低于目标粒度0.3μm，下调pH 0.04，并持续收料；
步骤5.将收集的物料进行固液分离，洗涤沉淀物；
步骤6.将沉淀物在100℃下烘干36h，得到正极材料前驱体。
分别取反应进行到第80h、84h的过程样测试(4h远低于前驱体颗粒在反应釜内的停留时间τ，仅有少量二次颗粒从溢流口排出，因此可视为釜内物料大致为同一批物料)。采用X-pert Highscore软件拟合得出的前驱体的生长层错率fD分别为0.83％和0.74％，两次测得的fD的差值为0.09％，基于激光粒度仪测试结果计算出的span分别为1.08和1.03。
一种正极材料前驱体，由上述制备方法制备得到，正极材料前驱体的化学式为Ni0.95Co0.02Mn0.03(OH)2。
一种正极材料的制备方法，包括以下步骤：
(1)将如上所述的正极材料前驱体与LiOH、添加剂MoO3和B2O3混合均匀后，在有氧气氛下进行一次烧结得到一烧物料，其中正极材料前驱体与LiOH按照Li/(Ni+Co+Mn)的摩尔比为1.01进行混合，MoO3和B2O3的添加量分别为3000ppm和800ppm(以MoO3和B2O3中Mo和B占前驱体质量计)，一次烧结的温度为832℃，一次烧结的温度为32h；
(2)将步骤(1)得到的一烧物料经过粗破碎、细破碎后再与添加剂MgCO3和LiF混合均匀，在有氧气氛下进行二次烧结，得到正极材料，其中MgCO3和LiF的添加量分别为2000ppm和1000ppm(以MgCO3和LiF中Mg和F占基材重量计)，二次烧结的温度为300℃，二次烧结的温度为9h。
一种正极材料，由上述制备方法制备得到，正极材料的化学式为Li(Ni0.95Co0.02Mn0.03)0.997Mo0.00289La0.00053O2@Mg0.00817F0.00368。
试验例：
分别将实施例1-4及对比例1-2的正极材料配成扣式电池进行锂离子电池电化学性能测试，其具体步骤为：以N-甲基吡咯烷酮为溶剂，按照质量比8︰1︰1的比例将正极材料与乙炔黑、PVDF混合均匀，涂覆于铝箔上，经80℃鼓风干燥8h后，于120℃真空干燥12h。在氩气保护的手套箱中装配电池，负极为金属锂片，隔膜为聚丙烯膜，电解液为1M LiPF6-EC/DMC(1:1，v/v)。在特定的截止电压下以0.1C进行倍率放电，测试首次放电容量及首次效率，随后在与半电池测试中同样的截止电压下以1C的倍率循环100圈，记录100圈后的循环容量保持率，测试结果见表1，其中实施例1和对比例1制备的正极材料的循环容量保持率对比图如图6所示，实施例1和对比例1中共沉淀法制备的前驱体成品的X射线衍射图(XRD)如图7所示，XRD显示前驱体的主要峰位并未发生明显偏移，但实施例1中，I(101)/I(001)峰强比明显更小。理论研究已经证实I(101)与I(001)峰强的比值是与前驱体中的缺陷相关，I(101)/I(001)峰强比越小，前驱体中缺陷越多，由此直接证实了实施例1中通过工艺条件的变更可以调控前驱体中缺陷的形成，从而实现具有梯度缺陷结构前驱体的可控制备。本发明实施例1和对比例1中共沉淀法制备的前驱体成品的粒度分布图如图8所示。由图可知，实施例1和对比例1中前驱体的粒度分布都符合正态分布的特点，但实施例1对应前驱体的粒度分布更“矮胖”，表明其粒度分布更宽泛，而对比例1中前驱体粒度分布相对集中，前驱体在粒度分布上的表现与实施例中工艺调节的机理实现了相互印证。
表1：电池性能测试结果

由表1可知，本发明的制备方法制备得到正极材料前驱体在制备成正极材料后具有优异的电化学性能，其0.1C放电容量能达到192mAh/g以上，首次效率能达到90.8％以上，100圈后的循环容量保持率能达到90.1％以上。
上述实施例为本发明较佳的实施方式，但本发明的实施方式并不受上述实施例的限制，其他的任何未背离本发明的精神实质与原理下所作的改变、修饰、替代、组合、简化，均应为等效的置换方式，都包含在本发明的保护范围之内。

Claims (10)

  1. 一种正极材料前驱体，其特征在于：所述正极材料前驱体由共沉淀反应制备得到，且在所述共沉淀反应过程中控制体系的pH为9-12，当所述共沉淀反应达到平衡后，任意相隔4h的两个时段测得体系中晶体的形变层错率fD的差值≥0.7％，所述形变层错率fD＝0.19FWHM(101)–0.055FWHM(102)–0.5/D(001)，其中，FWHM(101)为(101)衍射峰的半峰宽，FWHM(102)为(102)衍射峰的半峰宽，D(001)为(001)晶面对应的晶粒尺寸。
  2. 根据权利要求1所述的一种正极材料前驱体，其特征在于：当所述共沉淀反应达到平衡后，所述体系中晶体的形变层错率fD为1％-10％。
  3. 根据权利要求1所述的一种正极材料前驱体，其特征在于：所述正极材料前驱体的粒度分布span值≥1.30。
  4. 根据权利要求1所述的一种正极材料前驱体，其特征在于：所述正极材料前驱体的化学式为NixCoyMnz(OH)2；其中0≤x≤1；0≤y≤0.9；0≤z≤0.9且x+y+z＝1。
  5. 一种如权利要求1-4任一项所述正极材料前驱体的制备方法，其特征在于：包括以下步骤：
    (1)将含镍钴锰的金属盐溶液、沉淀剂、络合剂和碱性底液混合反应，得到混合液，反应过程中控制体系的pH为9-12，当所述反应得到的前驱体晶体的粒度D50达到1-15μm后对体系的pH进行调整，以控制共沉淀反应平衡；
    (2)将步骤(1)得到的混合液固液分离，得到固体物，洗涤后，烘干，得到所述正极材料前驱体。
  6. 根据权利要求5所述的一种正极材料前驱体的制备方法，其特征在于：步骤(1)中，所述对pH进行调整是指当所述前驱体晶体的D50比目标粒度大0.3μm以上时，将体系的pH上调0.02-0.04；当所述前驱体晶体的D50比目标粒度小0.3μm以上时，将体系的pH下调0.03-0.06。
  7. 一种正极材料的制备方法，其特征在于：包括以下步骤：将权利要求1-4任一项所述的正极材料前驱体、锂源和添加剂混合，在有氧气氛下进行一次烧结，破碎后再与添加剂混合，在有氧气氛下进行二次烧结，制得所述正极材料。
  8. 根据权利要求7所述的一种正极材料的制备方法，其特征在于：所述添加剂为含有Ni、Co、Mn、Zr、Al、Mg、Ti、Sr、W、Y、Mo、Sb、Nb、Sn、Zn、La、Ce、B及F元素中的至少一种元素的化合物或化合物的组合。
  9. 一种正极材料，其特征在于：由权利要求7-8任一项所述的制备方法制备得到。
  10. 权利要求9所述的正极材料在制备锂离子电池中的应用。
PCT/CN2023/077443 2022-09-15 2023-02-21 一种正极材料前驱体、正极材料及其制备方法和应用 WO2024055513A1 (zh)

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