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CN-122025620-A - Doped lithium manganate positive electrode material and preparation method and application thereof

CN122025620ACN 122025620 ACN122025620 ACN 122025620ACN-122025620-A

Abstract

The invention belongs to the technical field of preparation of lithium manganate anode materials, and particularly relates to a doped lithium manganate anode material, and a preparation method and application thereof. The crystal face (111) of the lithium manganate crystal grain of the doped lithium manganate anode material comprises a plurality of dot-shaped bulges, the heights of the dot-shaped bulges are 20-200 nm, and the ratio of the diameters to the heights of the dot-shaped bulges is 1-11:1. The doped lithium manganate positive electrode material provided by the invention comprises a plurality of dot-shaped bulges, so that an efficient two-dimensional lithium ion diffusion channel can be provided, and meanwhile, a stable crystal framework of the doped lithium manganate positive electrode material can effectively inhibit manganese dissolution and lattice distortion in the charge and discharge process.

Inventors

  • Huang Tianliu
  • ZHOU TONG
  • JIANG JIANBING
  • GAO XUGUANG
  • XU HUAN
  • XIAO JIAXIANG
  • HU HUI

Assignees

  • 湘潭电化科技股份有限公司

Dates

Publication Date
20260512
Application Date
20260410

Claims (10)

  1. 1. The doped lithium manganate positive electrode material is characterized in that a (111) crystal face of a lithium manganate crystal grain comprises a plurality of punctiform bulges; the height of the dot-shaped bulges is 20 nm-200 nm; the ratio of the diameter to the height of the dot-shaped protrusions is 1-11:1; The preparation raw materials of the doped lithium manganate positive electrode material comprise a lithium source, a manganese source and a doped element source.
  2. 2. The doped lithium manganate positive electrode material according to claim 1, wherein at least one of the following (1) to (5) characteristics is satisfied: (1) In the lithium source, the manganese source and the doping element source, the molar ratio of Li (Mn+M) is 1.05-1.12:2, wherein M is the doping element; (2) In the manganese source and the doping element source, the molar ratio of the doping element to Mn is 0.005-0.05:1; (3) In the doping element source, the ion radius of the doping element is smaller than that of Mn 3+ ; (4) The doping element source comprises at least one of Mg 2+ 、Al 3+ 、Ti 4+ ; (5) The doping element source includes at least one of an oxide or hydroxide of Mg 2+ 、Al 3+ 、Ti 4+ .
  3. 3. The doped lithium manganate positive electrode material according to claim 1 or 2, wherein at least one of the following (1) to (2) characteristics is satisfied: (1) The lithium source comprises at least one of lithium carbonate and lithium oxalate; (2) The manganese source comprises at least one of manganous oxide and manganous oxide.
  4. 4. A method for preparing a doped lithium manganate positive electrode material, which is characterized by being used for preparing the doped lithium manganate positive electrode material according to any one of claims 1-3, and comprising the following steps: After sintering the precursor, quenching the product; the preparation raw materials of the precursor comprise a lithium source, a manganese source and a doping element source; In the quenching treatment, the cooling rate is more than 30 ℃ per minute.
  5. 5. The method for preparing a doped lithium manganate positive electrode material according to claim 4, wherein the cooling rate in the quenching treatment is 30 ℃ per minute to 100 ℃ per minute.
  6. 6. The method for producing a doped lithium manganate positive electrode material according to claim 4 or 5, wherein the sintering treatment comprises primary sintering and secondary sintering.
  7. 7. The method for preparing a doped lithium manganate positive electrode material according to claim 6, wherein at least one of the following features (1) to (2) is satisfied: (1) The primary sintering comprises the following steps: In an oxygen-containing atmosphere, heating the precursor to 650-750 ℃ and naturally cooling the precursor after sintering; (2) The secondary sintering comprises the following steps: and in an oxygen-containing atmosphere, heating the primary sintered product to 850-950 ℃ and then preserving heat.
  8. 8. The method for preparing a doped lithium manganate positive electrode material according to claim 7, wherein at least one of the following characteristics (1) to (4) is satisfied: (1) In the primary sintering, the temperature rising rate is 1-5 ℃ per minute; (2) In the primary sintering, the sintering time is 6-12 hours; (3) In the secondary sintering, the temperature rising rate is 1-5 ℃ per minute; (4) In the secondary sintering, the heat preservation time is 0.5 h-2.5 h.
  9. 9. The method for producing a doped lithium manganate positive electrode material according to any one of claims 4, 5, 7 or 8, wherein the precursor production comprises the steps of: Ball milling and mixing the preparation raw materials of the precursor according to a preset proportion.
  10. 10. An application of a doped lithium manganate positive electrode material, which is characterized in that the doped lithium manganate positive electrode material as claimed in any one of claims 1-3 is applied in the field of batteries.

Description

Doped lithium manganate positive electrode material and preparation method and application thereof Technical Field The invention belongs to the technical field of preparation of lithium manganate anode materials, and particularly relates to a doped lithium manganate anode material, and a preparation method and application thereof. Background Spinel type lithium manganate (LiMn 2O4) is regarded as one of important positive electrode materials of the power lithium ion battery because of the advantages of rich resources, low cost, high safety, environmental friendliness and the like. However, conventional lithium manganates have serious capacity fade problems during cycling, especially at high temperatures. The method mainly comprises the steps of 1) dissolving manganese ions, particularly disproportionation dissolution of trivalent manganese in electrolyte, 2) lattice distortion caused by Jahn-Teller effect in the charging and discharging process, and 3) unstable crystal structure in the lithium ion deintercalation process, so that the transmission kinetics of lithium ions in the later period of circulation are poor. The prior art generally employs bulk doping (e.g., al, mg, cr, ni, etc.) to stabilize the crystal structure, or surface coating to inhibit manganese dissolution. However, conventional bulk doping can improve structural stability to some extent, but often at the expense of initial capacity and ionic/electronic conductivity of the material. While the surface coating may hinder lithium ion migration. More importantly, these methods are generally limited to macroscopic "bulk" or "surface" modifications that fail to radically reconstruct the lithium ion transport channels and interfacial stability within the material. Disclosure of Invention In order to solve the problems, the invention provides a doped lithium manganate positive electrode material, and a preparation method and application thereof. To solve at least one aspect of the above technical problems. The invention is realized by the following technical scheme: in a first aspect, the invention provides a doped lithium manganate positive electrode material, wherein a (111) crystal face of a lithium manganate crystal grain comprises a plurality of punctiform bulges; the height of the dot-shaped bulges is 20 nm-200 nm; the ratio of the diameter to the height of the dot-shaped protrusions is 1-11:1; The preparation raw materials of the doped lithium manganate positive electrode material comprise a lithium source, a manganese source and a doped element source. In some possible implementations, the molar ratio of Li (Mn+M) in the lithium source, the manganese source, and the dopant element source is 1.05-1.12:2, where M is the dopant element. In some possible implementations, the molar ratio of the doping element to Mn in the manganese source and the doping element source is 0.005-0.05:1. In some possible implementations, the doping element source has a doping element with an ionic radius that is less than the ionic radius of Mn 3+. In some possible implementations, the doping element in the doping element source includes at least one of Mg 2+、Al3+、Ti4+. In some possible implementations, the doping element in the doping element source is Mg 2+. In some possible implementations, the doping element source includes at least one of an oxide or hydroxide of Mg 2+、Al3+、Ti4+. In some possible implementations, the dopant element source includes at least one of MgO, al (OH) 3. In some possible implementations, the lithium source includes at least one of lithium carbonate, lithium oxalate. In some possible implementations, the manganese source includes at least one of manganomanganic oxide, manganomanganic oxide. In a second aspect, the present invention provides a method for preparing a doped lithium manganate cathode material, which is used for preparing the doped lithium manganate cathode material, and includes the following steps: After sintering the precursor, quenching the product; the preparation raw materials of the precursor comprise a lithium source, a manganese source and a doping element source; In the quenching treatment, the cooling rate is more than 30 ℃ per minute. In some possible implementations, the cooling rate is 30 ℃ per minute to 100 ℃ per minute in the quenching process. In some possible implementations, the sintering process includes primary sintering and secondary sintering. In some possible implementations, the primary sintering includes the steps of: and in an oxygen-containing atmosphere, heating the precursor to 650-750 ℃ and naturally cooling the precursor after sintering. In some possible implementations, the secondary sintering includes the steps of: and in an oxygen-containing atmosphere, heating the primary sintered product to 850-950 ℃ and then preserving heat. In some possible implementations, the rate of temperature rise in the primary sintering is 1 ℃ per minute to 5 ℃ per minute. In some possible implementations, the si