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CN-121983570-A - Lithium-rich manganese-based positive electrode material, preparation method thereof, positive electrode plate and battery

CN121983570ACN 121983570 ACN121983570 ACN 121983570ACN-121983570-A

Abstract

The application provides a lithium-rich manganese-based positive electrode material, a preparation method thereof, a positive electrode plate and a battery, wherein the lithium-rich manganese-based positive electrode material comprises a lithium-rich manganese-based core material and a coating layer coated on the lithium-rich manganese-based core material; the alkali metal layer of the lithium-rich manganese-based core material at least comprises Mg element, and the coating layer comprises lithium fluoride. The lithium-rich manganese-based positive electrode material has high capacity, high structural stability and excellent interface durability, and can meet the performance requirement of a high-energy-density battery under a complex working condition.

Inventors

  • DONG LIANGCHEN
  • FENG DAOYAN
  • ZHANG WENXIU

Assignees

  • 宁波容百新能源科技股份有限公司

Dates

Publication Date
20260505
Application Date
20260129

Claims (10)

  1. 1. The lithium-rich manganese-based positive electrode material is characterized by comprising a lithium-rich manganese-based core material and a coating layer coated on the lithium-rich manganese-based core material; the alkali metal layer of the lithium-rich manganese-based core material at least comprises Mg element, and the coating layer comprises lithium fluoride.
  2. 2. The lithium-rich manganese-based positive electrode material according to claim 1, wherein the lithium fluoride contains a (200) crystal plane; and the included angle between the lattice fringes of the (200) crystal face of the lithium fluoride and the lattice fringes of the (003) crystal face of the lithium-rich manganese-based core material is smaller than or equal to 10 degrees.
  3. 3. The lithium-rich manganese-based positive electrode material according to claim 1, wherein the d (Li-O-Li) spacing of the lithium-rich manganese-based positive electrode material is 2.590-2.600 a.
  4. 4. The lithium-rich manganese-based positive electrode material according to any one of claims 1 to 3, wherein a chemical formula of the lithium-rich manganese-based positive electrode material includes Li 1+x Ni a Co b Mn c M d Mg e O y F z R h , wherein a+b+c+d+e=1.0,0.1≤a<0.5,0≤b≤0.15,0.5≤c≤0.7,d≤0.2,0.10≤x≤0.5,0<e≤0.015,2.13≤y≤2.50,0.006≤z≤0.03,0.001≤h≤0.02;1.95+x≤y+z+h≤2.05+x,z+h≤0.2y,M includes one or several of Al, P, ca, ti, cr, fe, cu, zn, sr, se, Y, zr, si, nb, mo, sb, sn, te, ba, cs, ta, W, la, ce, sm and Gd, and R includes one or several of S, cl, B, and C.
  5. 5. A lithium-rich manganese-based positive electrode material according to any one of claims 1 to 3, wherein the thickness of the coating layer is 2nm to 20nm, or the thickness of the coating layer is 2nm to 14nm; And/or; The specific surface area of the lithium-rich manganese-based positive electrode material is 0.3-3.0 m 2 /g, or the specific surface area of the lithium-rich manganese-based positive electrode material is 1.4-1.8 m 2 /g.
  6. 6. The lithium-rich manganese-based positive electrode material according to any one of claims 1 to 3, wherein D50, D50 of 1.0 μm or less and 15.0 μm or D50 of 6.5 μm or less and 12.2 μm; And/or; The coating layer also comprises at least one element of La, zr, ba and Cs.
  7. 7. A method for preparing the lithium-rich manganese-based positive electrode material according to any one of claims 1 to 6, comprising the steps of: Mixing and reacting a metal salt solution, a precipitator and a complexing agent to obtain a hydroxide precursor, mixing the hydroxide precursor and a lithium source, and performing first sintering to obtain an anode material intermediate; and mixing the intermediate of the positive electrode material with fluoride, and performing second sintering treatment to obtain the lithium-rich manganese-based positive electrode material, wherein the fluoride at least comprises magnesium fluoride.
  8. 8. The method of claim 7, wherein the first sintering is performed by mixing a hydroxide precursor, a lithium source, and a modifying additive comprising a compound comprising an element M comprising one or more of Al, P, ca, ti, cr, fe, cu, zn, sr, se, Y, zr, si, nb, mo, sb, sn, te, ba, cs, ta, W, la, ce, sm and Gd; The fluoride also comprises fluoride I, wherein the fluoride I comprises at least one of LaF 3 、ZrF 4 、BaF 2 and CsF, and/or the second sintering time is 2-5h; and/or the temperature rising rate of the second sintering is greater than or equal to 10 ℃ per minute, or the temperature rising rate of the second sintering is 10-15 ℃ per minute; And/or the temperature of the second sintering is 800-900 ℃.
  9. 9. A positive electrode sheet, characterized in that the electrode sheet comprises the lithium-rich manganese-based positive electrode material according to any one of claims 1 to 6.
  10. 10. A battery comprising the positive electrode sheet according to claim 9.

Description

Lithium-rich manganese-based positive electrode material, preparation method thereof, positive electrode plate and battery Technical Field The application relates to the technical field of lithium ion batteries, in particular to a lithium-rich manganese-based positive electrode material, a preparation method thereof, a positive electrode plate and a battery. Background The lithium-rich manganese-based positive electrode material (Li-RICH LAYERED oxide cathode materials) is one of core components of a high-energy-density lithium ion battery, and is widely applied to the fields of new energy automobiles, energy storage systems and consumer electronics. The positive electrode material is known in the industry as having high energy density, but is unacceptable in voltage attenuation and capacity attenuation behind 250-300 mAhg -1 capacity, and cannot meet industrial application. Meanwhile, the high voltage used by the battery system causes the interface to have non-negligible side reaction, and the battery system simultaneously has the problems of gas production, storage performance degradation and the like. In addition, the accumulation of anions by the shallow discharge SOC gradually accumulates material stress, resulting in rapid deterioration of performance. The above results indicate that the application of high-capacity (> 250mAhg -1) lithium-rich positive electrode to liquid battery systems presents a number of technical bottlenecks, one by one, that need to be overcome. In a short period, a feasible solution is to seek a solution of balancing capacity exertion and structural stability, and the solution is smoothly introduced into industrial application so as to attract more academic and industrial research and development and promote the final landing of a high-capacity system. Therefore, the voltage window is properly regulated and used to 4.4-4.5V, the capacity of the battery is kept to be 210-230 mAhg -1, and the battery is an industrialization path with high feasibility in a short period. Under this condition, the series of problems arising from the ultra-high capacity (> 250mAhg -1) is all alleviated or partially resolved. Even so, the voltage window of 4.4-4.5V is still not low, serious interface side reaction, structural collapse caused by anion redox and other problems still need to be solved, especially under the condition of high temperature, the kinetic improvement leads to higher capacity exertion at normal temperature, the anion oxidation leads to structural rearrangement and interface side reaction aggravation, and the cycle performance is obviously deteriorated at normal temperature. Therefore, there is a need to develop a lithium-rich manganese-based positive electrode material having high capacity, high structural stability and excellent interface durability to meet the performance requirements of high energy density batteries under complex operating conditions. Disclosure of Invention The lithium-rich manganese-based positive electrode material, the preparation method thereof, the positive electrode plate and the battery provided by the application have the advantages of high capacity, high structural stability and excellent interface durability, and can meet the performance requirements of the high-energy-density battery under complex working conditions. In a first aspect, the application provides a lithium-rich manganese-based positive electrode material, which comprises a lithium-rich manganese-based core material and a coating layer coated on the lithium-rich manganese-based core material, wherein an alkali metal layer of the lithium-rich manganese-based core material at least comprises Mg element, and the coating layer comprises lithium fluoride. In one possible embodiment, the lithium fluoride contains (200) crystal planes, and the angle between the lattice fringes of the (200) crystal planes of the lithium fluoride and the lattice fringes of the (003) crystal planes of the lithium-rich manganese-based core material is less than or equal to 10 °. In one possible embodiment, the d (Li-O-Li) spacing of the lithium-rich manganese-based positive electrode material is 2.590-2.600A. In one possible embodiment, the chemical formula of the lithium-rich manganese-based positive electrode material includes Li1+xNiaCobMncMdMgeOyFzRh, in which a+b+c+d+e=1.0,0.1≤a<0.5,0≤b≤0.15,0.5≤c≤0.7,d≤0.2,0.10≤x≤0.5,0<e≤0.015,2.13≤y≤2.50,0.006≤z≤0.03,0.001≤h≤0.02;1.95+x≤y+z+h≤2.05+x,z+h≤0.2y,M includes one or more of Al, P, ca, ti, cr, fe, cu, zn, sr, se, Y, zr, si, nb, mo, sb, sn, te, ba, cs, ta, W, la, ce, sm and Gd, and R includes one or more of S, cl, B, and C. In one possible embodiment, the thickness of the coating layer is 2nm to 20nm. In one possible embodiment, the thickness of the coating layer is 2nm to 14nm. In one possible embodiment, the specific surface area of the lithium-rich manganese-based positive electrode material is 0.3-3.0 m 2/g. In one possible implementation mode, the specific su