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CN-121123257-B - Ternary positive electrode material, preparation method and application thereof

CN121123257BCN 121123257 BCN121123257 BCN 121123257BCN-121123257-B

Abstract

The invention discloses a ternary positive electrode material, a preparation method and application thereof, and relates to the technical field of lithium batteries. The ternary positive electrode material provided by the invention has the characteristics that the proportion of secondary particles in particles with the longest Feret diameter of Dv90 or more is 30% or more, the cumulative volume percentage corresponding to the most frequent particle diameter Dm is less than 70%, the powder flow rate S is 4S/50 g-20S/50 g, the value range of Dv5/Dm 3T after 3T pressing is 0.2-0.6, and meanwhile, the ternary positive electrode material meeting the characteristics has very high compaction density, and the degree of deviation of small particle powder from the most frequent particles after rolling of the positive electrode material particles is small, so that the phenomena of contact failure and pulverization separation are not easy to occur, thereby being beneficial to improving the cycle stability of a battery.

Inventors

  • YU HAIJUN
  • HUANG WEIYAN
  • LI CHANGDONG

Assignees

  • 广东邦普循环科技有限公司

Dates

Publication Date
20260505
Application Date
20251117

Claims (10)

  1. 1.A ternary positive electrode material characterized by comprising primary particles and secondary particles agglomerated from the primary particles, and satisfying the conditions (1) - (4) at the same time: The condition (1) is that the ratio of the secondary particles to the total number of particles in the particles with the longest Feret diameter of more than Dv90 is 30% -100%, and Dv90 is the particle diameter value ‌ corresponding to the particle cumulative volume distribution of 90% in the particle size distribution curve; In the particle size distribution curve, the cumulative volume percentage corresponding to the most frequent particle diameter Dm is smaller than 70%, and the most frequent particle diameter Dm refers to the particle size value corresponding to the largest volume percentage in the particle size distribution curve; the condition (3) is that the powder flow rate S is 4S/50 g-20S/50 g; The condition (4) is that the maximum frequency grain diameter after 3T pressing is Dm 3T , the value range of Dv5/Dm 3T after 3T pressing is 0.2-0.6, dv5 after 3T pressing is 1.00 mu m-1.90 mu m, and Dm 3T after 3T pressing is 3 mu m-4.72 mu m.
  2. 2. The ternary positive electrode material of claim 1, wherein the ternary positive electrode material meets at least one of the following features A1-B1: the characteristic A1 is that the particle size distribution width span is 1.05-1.40; The characteristic B1 is that the compaction density is 2.7g/cm 3 ~3.5g/cm 3 .
  3. 3. A method of preparing the ternary cathode material of claim 1 or 2, comprising: Carrying out spray pyrolysis on the metal mixed solution in a spray pyrolysis instrument provided with a gas-solid separation device, obtaining a first metal oxide solid solution at the bottom of the gas-solid separation device, and separating at the top of the gas-solid separation device to obtain a second metal oxide solid solution; Taking the second metal oxide solid solution as a seed crystal to carry out precipitation reaction to prepare a carbonate precursor; mixing the first metal oxide solid solution with a first lithium source for first sintering to obtain first particles; mixing the carbonate precursor with a second lithium source for second sintering to obtain second particles; and mixing the first particles with the second particles to prepare a positive electrode material.
  4. 4. The method according to claim 3, wherein the metal mixture is sprayed into a reaction furnace from an atomizer of the spray pyrolysis apparatus, and then enters the gas-solid separation apparatus, and the large-particle product output from the bottom of the gas-solid separation apparatus is crushed and dried to obtain the first metal oxide solid solution, and the small particles obtained by filtering the gas flow output from the top of the gas-solid separation apparatus are the second metal oxide solid solution.
  5. 5. The method of producing according to claim 4, wherein the process of producing the first metal oxide solid solution and the second metal oxide solid solution has at least one of the following characteristics A2-G2: The method is characterized in that the spray pyrolysis temperature is 600-1000 ℃ and the spray pyrolysis time is 4-8 hours; The characteristic B2 is that the particle size of the first metal oxide solid solution is 200 nm-3000 nm, and the distribution width span is 2.4-3.8; the characteristic C2 is that the particle diameter Dv50 of the second metal oxide solid solution is 1000 nm-2000 nm, and the distribution width span is 1.2-2.0; The characteristic D2 is that large particles output from the bottom of the gas-solid separation device are put into water with the temperature below 60 ℃ for water-cooling crushing; The characteristic E2 is that the molar ratio of nickel to cobalt to manganese is (0.35-0.8): (0.1-0.35) by regulating and controlling the dosages of the nickel source, the cobalt source and the manganese source; the method is characterized by comprising the steps of F2, adding doped metal salt when preparing the metal mixed solution, wherein the doped metal is at least one selected from Y, ln, V, re, zr, ti, ca, mg, W and Al, and feeding the doped metal salt according to the content of doped elements in the anode material of 0-1000 ppm; And the characteristic G2 is that the nickel source, the cobalt source, the manganese source and the doped metal salt are all soluble salts, and the solvent is water.
  6. 6. The preparation method of the carbonate precursor according to claim 3, wherein the preparation process of the carbonate precursor comprises the steps of mixing the second metal oxide solid solution, the precipitator solution and the complexing agent solution to obtain a base solution, introducing a salt solution, the precipitator solution and the complexing agent solution into the base solution to perform precipitation reaction, reacting until the particle Dv50 reaches 3-8 μm, and stopping feeding, wherein the salt solution contains nickel salt, cobalt salt and manganese salt.
  7. 7. The method of preparing according to claim 6, wherein the process of preparing the carbonate precursor has at least one of the following features A3-J3: the characteristic A3 is that the reaction pH value is maintained at 10-12 by regulating and controlling the flow rate of the precipitator solution, and the ammonia concentration is maintained at 6-10 g/L by controlling the flow rate of the complexing agent solution; The characteristic B3 is that the precipitation reaction temperature is controlled to be 70-90 ℃; the characteristic C3 is that in the base solution, the concentration of the second metal oxide solid solution is 50 g/L-70 g/L, the pH value of the base solution is 10-12, and the concentration of ammonia is 6 g/L-10 g/L; the characteristic D3 is that the flow rate of the salt solution is 1L/h-5L/h; The characteristic E3 is that the molar ratio of Ni, co and Mn in the salt solution is (0.35-0.8): (0.1-0.35); the characteristic F3 is that the total concentration of metal ions in the salt solution is 1.5 mol/L-2.5 mol/L; the characteristic G3 is that the stirring speed is controlled to be 500 rpm-800 rpm in the precipitation process; the characteristic H3 is that the precipitator solution is carbonate solution, and the carbonate is at least one of sodium carbonate, sodium bicarbonate, potassium carbonate and potassium bicarbonate, and the concentration of the precipitator solution is 1.5 mol/L-3 mol/L; the complexing agent solution is ammonia water solution; And (3) after stopping feeding, carrying out solid-liquid separation, and washing and drying the obtained solid material.
  8. 8. The method according to claim 3, wherein the sintering temperature of the first sintering is 800 ℃ to 1000 ℃ and the time is 8 hours to 12 hours; And/or the second sintering comprises the steps of firstly sintering for 4-6 hours at 600-800 ℃, and then sintering for 2-4 hours at 800-1000 ℃; and/or the molar ratio of lithium in the first lithium source to the total amount of metal in the first metal oxide solid solution is (1.05-1.10): 1; and/or, the first lithium source and the first metal oxide solid solution are mixed by a wet method; And/or the molar ratio of lithium in the second lithium source to the total metal in the carbonate precursor is (1.05-1.10): 1; And/or the first lithium source is selected from at least one of lithium hydroxide, lithium oxalate, and lithium acetate; And/or the second lithium source is selected from at least one of lithium carbonate, lithium hydroxide, and lithium acetate; and/or, the mass ratio of the first particles in the total amount of the first particles and the second particles is 20% -80%; And/or mixing the first particles and the second particles, crushing, sieving and demagnetizing to obtain the anode material.
  9. 9. The positive electrode plate is characterized by comprising the ternary positive electrode material according to any one of claims 1-2 or the ternary positive electrode material prepared by the preparation method according to any one of claims 3-8.
  10. 10. A lithium battery comprising the positive electrode sheet of claim 9.

Description

Ternary positive electrode material, preparation method and application thereof Technical Field The invention relates to the technical field of lithium batteries, in particular to a ternary positive electrode material, a preparation method and application thereof. Background The nickel cobalt lithium manganate ternary (NCM) positive electrode material has the advantages of high specific capacity, high discharge voltage, high energy density, good multiplying power performance and the like, can provide longer endurance mileage and faster charging speed for new energy automobiles, becomes one of the main current positive electrode materials of the power battery, and occupies a larger market share. Compared with the secondary spherical ternary positive electrode material, the single-crystal ternary positive electrode material has high compressive strength, so that the single-crystal ternary positive electrode material can avoid the generation of inter-crystal cracks due to long-cycle strain accumulation, and the cycle performance is improved. The existing ternary monocrystal material has poor particle uniformity, more particle edges and corners and low sphericity, so that the ternary monocrystal material is easy to crush when rolled to prepare pole pieces, or the edges and corners are used as stress concentration points to easily crack in the circulation process, thereby reducing the circulation performance. Therefore, there is a need to provide a ternary positive electrode material with high compacted density and good cycle performance. In view of this, the present invention has been made. Disclosure of Invention The invention aims to provide a ternary positive electrode material, a preparation method and application thereof, and aims to simultaneously improve the compaction density and the cycling stability of the ternary positive electrode material, and further improve the volume specific capacity and the cycling stability. The invention is realized in the following way: In a first aspect, the present invention provides a ternary positive electrode material comprising primary particles and secondary particles agglomerated from the primary particles, while satisfying the conditions (1) - (4): The condition (1) is that the ratio of secondary particles to the total number of particles in particles with the longest Feret diameter of more than Dv90 is 30% -100%, and Dv90 is a particle diameter value ‌ corresponding to the case that the cumulative volume distribution of the particles in a particle size distribution curve reaches 90%; In the particle size distribution curve, the cumulative volume percentage corresponding to the most frequent particle diameter Dm is smaller than 70%, and the most frequent particle diameter Dm refers to the particle size value corresponding to the largest volume percentage in the particle size distribution curve; the condition (3) is that the powder flow rate S is 4S/50 g-20S/50 g; And (4) the maximum frequency grain diameter after 3T pressing is Dm 3T, and the value range of Dv5/Dm 3T after 3T pressing is 0.2-0.6. In an alternative embodiment, the ternary single crystal positive electrode material satisfies at least one of the following features A1-D1: the characteristic A1 is that the particle size distribution width span is 1.05-1.40; The Dv5 after 3T pressing is 1-3 mu m; the Dm 3T after 3T pressing is 3-8 mu m; Characteristic D1 the compacted density is 2.7g/cm 3~3.5g/cm3. In a second aspect, the present invention provides a method for preparing the ternary cathode material according to the foregoing embodiment, including: carrying out spray pyrolysis on the metal mixed solution in a spray pyrolysis instrument provided with a gas-solid separation device, obtaining a first metal oxide solid solution at the bottom of the gas-solid separation device, and separating at the top of the gas-solid separation device to obtain a second metal oxide solid solution; taking the second metal oxide solid solution as a seed crystal to carry out precipitation reaction to prepare a carbonate precursor; mixing a first metal oxide solid solution with a first lithium source to perform first sintering to obtain first particles; mixing the carbonate precursor with a second lithium source for second sintering to obtain second particles; the first particles and the second particles are mixed to prepare a positive electrode material. In an alternative embodiment, the metal mixed solution is sprayed into a reaction furnace from an atomizer of a spray pyrolysis apparatus, then enters a gas-solid separation device, large particle products output from the bottom of the gas-solid separation device are crushed and dried to obtain a first metal oxide solid solution, and small particles obtained by collecting air flow output from the top of the gas-solid separation device after filtering are a second metal oxide solid solution. In an alternative embodiment, the process of preparing the first and second metal oxid