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CN-117361646-B - Lithium-rich manganese-based precursor, and preparation method and application thereof

CN117361646BCN 117361646 BCN117361646 BCN 117361646BCN-117361646-B

Abstract

The invention discloses a lithium-rich manganese-based precursor, and a preparation method and application thereof. The lithium-rich manganese-based precursor is nickel cobalt manganese hydroxide doped with elements, and doping elements in the lithium-rich manganese-based precursor comprise Zr and W. The invention carries out co-doping on nickel cobalt manganese hydroxide by zirconium and tungsten, which is beneficial to the improvement of the electrochemical performance of the material, in particular to the cycle performance and the first effect.

Inventors

  • ZHANG KUN
  • ZHU XIAOSHUAI
  • LI CONG
  • XU KAIHUA
  • JIA DONGMING
  • WANG WENGUANG

Assignees

  • 荆门市格林美新材料有限公司
  • 格林美股份有限公司

Dates

Publication Date
20260508
Application Date
20231010

Claims (20)

  1. 1. The lithium-rich manganese-based positive electrode material is characterized in that the lithium-rich manganese-based positive electrode material is prepared by adopting a lithium-rich manganese-based precursor; The lithium-rich manganese-based precursor is nickel cobalt manganese hydroxide doped with elements, and doping elements in the lithium-rich manganese-based precursor comprise Zr and W; the surface of the lithium-rich manganese-based positive electrode material is sequentially provided with a modified layer and a coating layer; the lithium-rich manganese-based positive electrode material is prepared by adopting the following method, and the method comprises the following steps: (1) Mixing lithium salt and a lithium-rich manganese-based precursor, calcining at a high temperature to obtain the lithium-rich manganese-based positive electrode material, mixing a lithium-rich manganese-based positive electrode material matrix with NH 4 HCO 3 , heating to decompose NH 4 HCO 3 into CO 2 and NH 3 , reacting with the lithium-rich manganese-based positive electrode material matrix, and epitaxially forming a spinel-structured lithium-rich manganese-based positive electrode material on the particle surface of the lithium-rich manganese-based positive electrode material matrix to serve as a modified layer; (2) And (3) ball-milling and mixing the lithium-rich manganese-based positive electrode material prepared in the step (1) with oxide and phosphate, and performing one-time heat treatment to obtain the lithium-rich manganese-based positive electrode material with the coating layer.
  2. 2. The lithium-rich manganese-based positive electrode material according to claim 1, wherein in the lithium-rich manganese-based precursor, the molar ratio of manganese, nickel and cobalt is x:z, wherein x >0.5,0.4> y >0.01,0.4> z >0.01, and x+y+z <1.
  3. 3. The lithium-rich manganese-based positive electrode material according to claim 1, wherein the doping amount of Zr element is 1000ppm to 3000ppm based on the total mass of the lithium-rich manganese-based precursor.
  4. 4. The lithium-rich manganese-based positive electrode material according to claim 1, wherein the doping amount of the W element is 700ppm to 1500ppm based on the total mass of the lithium-rich manganese-based precursor.
  5. 5. The lithium-rich manganese-based positive electrode material according to claim 1, wherein the molar ratio of Zr and W is (1.5-3): 1.
  6. 6. The lithium-rich manganese-based positive electrode material according to claim 1, wherein Cr is further included in the doping element.
  7. 7. The lithium-rich manganese-based positive electrode material according to claim 6, wherein the ratio of the total molar amount of Zr and W to the molar amount of Cr is (1.5-4): 1.
  8. 8. The lithium-rich manganese-based positive electrode material according to claim 1, wherein the particle diameter of the lithium-rich manganese-based precursor is 5 μm to 10 μm.
  9. 9. The lithium-rich manganese-based positive electrode material according to claim 1, wherein the preparation method of the lithium-rich manganese-based precursor comprises the steps of: Preparing a nickel-cobalt-manganese mixed solution, a base solution, a precipitator solution, a complexing agent solution, a zirconium source solution and a tungsten source solution; adding the nickel-cobalt-manganese mixed solution, the precipitator solution and the complexing agent solution into a reaction container containing base solution, controlling the temperature and the pH value of a reaction system to preset values, adding a zirconium source solution and a tungsten source solution after the coprecipitation reaction starts, and continuing to react to obtain a lithium-rich manganese-based precursor.
  10. 10. The lithium-rich manganese-based positive electrode material according to claim 9, wherein the addition rate of the nickel-cobalt-manganese mixed solution is 10L/h to 100L/h.
  11. 11. The lithium-rich manganese-based positive electrode material according to claim 9, wherein the zirconium source in the zirconium source solution comprises Zr (at least one of SO 4 ) 2 、CH 4 NO 3 Zr and Zr (O 2 CCH 3 ) 4 ).
  12. 12. The lithium-rich manganese-based positive electrode material according to claim 9, wherein the concentration of the zirconium source solution is 0.1g/L to 3g/L.
  13. 13. The lithium-rich manganese-based positive electrode material according to claim 9, wherein the flow rate of the zirconium source solution is 0.3L/h to 3L/h.
  14. 14. The lithium-rich manganese-based positive electrode material according to claim 9, wherein the tungsten source in the tungsten source solution comprises at least one of ammonium tungstate and Na 2 WO 4 .
  15. 15. The lithium-rich manganese-based positive electrode material according to claim 9, wherein the concentration of the tungsten source solution is 0.1g/L to 3g/L.
  16. 16. The lithium-rich manganese-based positive electrode material according to claim 9, wherein the flow rate of the tungsten source solution is 0.3L/h to 3L/h.
  17. 17. The lithium-rich manganese-based positive electrode material according to claim 9, wherein the preparation method further comprises preparing a chromium source solution, and adding the chromium source solution and the nickel-cobalt-manganese mixed solution into a container in parallel flow for chromium doping.
  18. 18. The lithium-rich manganese-based positive electrode material according to claim 9, wherein the preset value of the temperature is 40 ℃ to 65 ℃ and the preset value of the pH is 9.5 to 11.5.
  19. 19. The lithium-rich manganese-based positive electrode material according to claim 9, wherein after controlling the temperature and the pH of the reaction system to preset values, stirring is started, and the zirconium source solution and the tungsten source solution are added under stirring, wherein the stirring speed is 200r/min-400r/min.
  20. 20. The lithium-rich manganese-based positive electrode material according to claim 1, wherein the oxide comprises at least one of Al 2 O 3 、ZrO 2 and MnO 2 .

Description

Lithium-rich manganese-based precursor, and preparation method and application thereof Technical Field The invention belongs to the technical field of lithium batteries, and particularly relates to a lithium-rich manganese-based precursor, and a preparation method and application thereof. Background The lithium-rich manganese-based positive electrode material has higher energy density and higher discharge capacity, and attracts wide attention. However, the lithium-rich manganese-based positive electrode material has lower conductivity, the contact resistance between an electrode and electrolyte is increased in the high-rate charge and discharge process, concentration polarization, side reaction and other reasons, and in practical power battery application, the lithium-rich manganese-based positive electrode material has poor performance under the high-rate charge and discharge condition, has low initial charge and discharge coulomb efficiency, and has the problem of poor cycle performance, so that the distance is very different from the practical use. CN108557905A discloses a lithium-rich manganese-based material precursor, which is a flake-shaped lithium-rich manganese-based material carbonate precursor, and the preparation process of the lithium-rich manganese-based material precursor comprises the steps of feeding a mixed salt solution, a precipitator and a complexing agent into a reactor at the same time at the speed of 0.12L/h-0.9L/h, controlling the reaction temperature to be 35-65 ℃, controlling the pH value to be 7.5-8.5, controlling the stirring speed to be 400rpm/min-1000rpm/min, aging for 5-20 h after the reaction is finished, and separating, washing and drying the precipitate to obtain the flake-shaped lithium-rich manganese-based material carbonate precursor. However, in the process of preparing the lithium-rich manganese-based material precursor, the particle size of the lithium-rich manganese-based material precursor is difficult to control, fine particles are easy to obtain, and the electrochemical performance of the lithium-rich manganese-based material precursor is further influenced. CN104466162B discloses a gradient lithium-rich manganese-based precursor and a preparation method of the gradient lithium-rich manganese-based positive electrode material, wherein the preparation method comprises the steps of preparing a mixed solution A, a mixed solution B and a solution C with different manganese ion contents, sequentially adding a first reactor, a second reactor and a third reactor for reaction, and performing serial circulation reaction on the first reactor, the second reactor and the third reactor to obtain the gradient lithium-rich manganese-based precursor. However, the preparation process of the method is complex and difficult to realize industrial production. Therefore, the simple preparation method of the lithium-rich manganese-based positive electrode material has higher initial effect and excellent cycle performance, and is a technical problem to be solved urgently. Disclosure of Invention Aiming at the problems in the prior art, the invention aims to provide a lithium-rich manganese-based precursor, and a preparation method and application thereof. According to the invention, specific elements are doped in the lithium-rich manganese-based precursor, so that the lithium-rich manganese-based positive electrode material prepared by adopting the lithium-rich manganese-based precursor has higher initial effect, excellent cycle performance and good voltage decay resistance effect. In order to achieve the above purpose, the invention adopts the following technical scheme: In a first aspect, the present invention provides a lithium-rich manganese-based precursor, the lithium-rich manganese-based precursor being an element doped nickel cobalt manganese hydroxide, the doping elements in the lithium-rich manganese-based precursor comprising Zr and W. The invention carries out co-doping on nickel cobalt manganese hydroxide by zirconium and tungsten, which is beneficial to the improvement of the electrochemical performance of the material, in particular to the cycle performance, the first effect and the second effect. The following preferred technical solutions are used as the present invention, but not as limitations on the technical solutions provided by the present invention, and the technical objects and advantageous effects of the present invention can be better achieved and achieved by the following preferred technical solutions. Preferably, in the lithium-rich manganese-based precursor, the molar ratio of manganese, nickel and cobalt is x:y:z, wherein x >0.5,0.4> y >0.01,0.4> z >0.01, and x+y+z <1. Preferably, the doping amount of Zr element is 1000ppm to 3000ppm, for example 1000ppm、1200ppm、1400ppm、1500ppm、1750ppm、1800ppm、2000ppm、2100ppm、2200ppm、2300ppm、2400ppm、2500ppm、2600ppm、2700ppm、2800ppm、2900ppm or 3000ppm, etc., based on the total mass of the lithium-rich manganese-based precurs