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CN-122025612-A - Preparation method of positive electrode active material, battery cell, battery device and electricity utilization device

CN122025612ACN 122025612 ACN122025612 ACN 122025612ACN-122025612-A

Abstract

The application relates to the technical field of batteries, and discloses a preparation method of an anode active material, a battery cell, a battery device and an electric device. The positive electrode film layer in the battery monomer comprises a positive electrode active material, wherein the positive electrode active material comprises a kernel and a coating layer arranged on the surface of the kernel, the kernel comprises lithium nickel manganese oxide, an M-phase doped layer and an M-surface enrichment layer are sequentially arranged from the kernel to the surface layer, M comprises one or more of B, al, ga, zr, sc, in, the coating layer is directly coated on the M-surface enrichment layer, and the coating layer comprises one or more of silicon nitride, silicon carbide, silicon dioxide and aluminum nitride. In the battery monomer provided by the embodiment of the application, the bulk doping and surface layer enrichment of doping elements and the direct cladding of the cladding layer material and the cladding layer are combined, so that the stability of the spinel-structure lithium nickel manganese oxide lattice structure at high temperature can be effectively improved, and the cycle performance of the battery monomer at high temperature is improved.

Inventors

  • Liang Jingshuang
  • ZHU YINJUN
  • LI HOUYONG
  • ZHANG XIAOLE

Assignees

  • 江苏时代新能源科技有限公司

Dates

Publication Date
20260512
Application Date
20260413

Claims (13)

  1. 1. The battery cell is characterized by comprising a positive electrode plate, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode film layer arranged on at least one side of the positive electrode current collector, the positive electrode film layer comprises a positive electrode active material, and the positive electrode active material comprises a core and a coating layer arranged on the surface of the core; The material of the inner core comprises lithium nickel manganese oxide, and comprises an M bulk doped layer and an M surface enriched layer in sequence from the core to the surface, wherein M comprises one or more of B, al, ga, zr, sc, in; wherein the coating layer is directly coated on the M surface layer enrichment layer, and the material of the coating layer comprises one or more of silicon nitride, silicon carbide, silicon dioxide and aluminum nitride.
  2. 2. The battery cell of claim 1, wherein the lithium nickel manganese oxide has a chemical formula LiM x Ni 0.5- x Mn 1.5-y O 4 , wherein 0< x is less than or equal to 0.08 and 0< y is less than or equal to 0.02.
  3. 3. The battery cell according to claim 1, wherein the molar doping amount of the M element in the M-phase doped layer is 0.04% -0.08%.
  4. 4. The battery cell according to claim 1, wherein the molar doping amount of the M element in the M-surface concentrated layer is 0% to 0.035%.
  5. 5. The battery cell of claim 1, wherein the M-skin enrichment layer has a thickness of 1nm to 10nm.
  6. 6. The battery cell of claim 1, wherein the phase purity of the inner core is greater than or equal to 95%.
  7. 7. The battery cell according to claim 1, wherein the mass content of the coating layer is 3% to 7% based on the positive electrode active material.
  8. 8. The battery cell according to claim 1, wherein the sphericity of the positive electrode active material is not less than 0.85.
  9. 9. The battery cell according to claim 1, wherein the positive electrode active material has a particle diameter Dv50 of 0.5 μm to 2 μm.
  10. 10. The battery cell according to claim 1, wherein the positive electrode active material has a particle size distribution coefficient of variation CV of 15% or less.
  11. 11. A method for preparing a positive electrode active material, comprising the steps of: (1) Pressing raw materials comprising a lithium source, a nickel source, a manganese source and an M source into blocks to obtain raw material blocks, taking the raw material blocks as anodes of arc discharge, firstly performing arc discharge under a water cooling condition, performing direct current arc plasma discharge treatment, and continuously cooling to room temperature under the water cooling condition after the treatment is finished to obtain a core; (2) And mixing the inner core with a coating layer material precursor, and then carrying out vapor deposition reaction to generate a coating layer on the inner core in situ to obtain the anode active material.
  12. 12. A battery device comprising the battery cell of any one of claims 1-10.
  13. 13. An electrical device comprising a battery cell according to any one of claims 1-10 or a battery device according to claim 12.

Description

Preparation method of positive electrode active material, battery cell, battery device and electricity utilization device Technical Field The application relates to the technical field of batteries, in particular to a preparation method of an anode active material, a battery cell, a battery device and an electric device. Background Lithium ion batteries are not only applied to energy storage power supply systems such as hydraulic power, firepower, wind power and solar power stations, but also widely applied to electric vehicles such as electric bicycles, electric motorcycles, electric automobiles, and the like, as well as a plurality of fields such as military equipment, aerospace, and the like. The continuous development of society places higher demands on the performance of lithium ion batteries. However, the performance of lithium ion batteries still needs to be further improved. Disclosure of Invention In view of the technical problems in the background art, the application provides a preparation method of an anode active material, a battery cell, a battery device and an electric device. In the battery monomer provided by the embodiment of the application, the bulk doping and surface layer enrichment of doping elements and the direct cladding of the cladding layer material and the cladding layer are combined, so that the stability of the spinel-structure lithium nickel manganese oxide lattice structure at high temperature can be effectively improved, and the cycle performance of the battery monomer at high temperature is improved. The application provides a battery cell, which comprises a positive electrode plate, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode film layer arranged on at least one side of the positive electrode current collector, the positive electrode film layer comprises a positive electrode active material, the positive electrode active material comprises a core and a coating layer arranged on the surface of the core, the core comprises lithium nickel manganese oxide, an M-phase doping layer and an M-surface enrichment layer are sequentially arranged from the core to the surface, M comprises one or more of B, al, ga, zr, sc, in, the coating layer is directly coated on the M-surface enrichment layer, and the coating layer comprises one or more of silicon nitride, silicon carbide, silicon dioxide and aluminum nitride. In the embodiment of the application, the radius of the defined M element is smaller, the lattice gap of the lithium nickel manganese oxide can be embedded, the lithium nickel manganese oxide is uniformly distributed in the whole area of the bulk phase of the material, partial metal ions are replaced, a metal-oxygen (M-O) bond frame with higher bonding strength is formed, the spacing and the connection state of the LiO 6 octahedron are optimized, the lattice distortion and the internal stress are reduced, and the bulk phase elasticity and the structural stability of the lithium nickel manganese oxide are greatly improved. On the basis, some M elements are enriched in the surface layer of the inner core, and the M elements basically have no local segregation or agglomeration, so that the directional reinforcement can be realized on the surface layer area which is most easily deteriorated by the lithium nickel manganese oxide, the disproportionation of the surface layer Mn3 + and the dissolution of Mn2 + are inhibited, and meanwhile, a uniform and compact CEI interface film is formed by induction, the interface impedance is reduced, and the charge-discharge polarization is reduced. In addition, the surface layer enriched M element can uniformly modify the surface of the lithium nickel manganese oxide and regulate and control the active site, so that the coating material directly grows on the surface layer enriched layer M in situ, no intermediate transition phase exists between the coating layer and the surface layer enriched layer M, the interface bonding strength is high, the interface is not easy to fall off, the interface defect is few, the electrolyte decomposition can be effectively inhibited, and the HF corrosion is reduced. The coating material can also maintain excellent structural rigidity at high temperature, provide stable mechanical constraint for the inner core, inhibit lattice distortion and volume deformation in the charge-discharge process, delay local phase change and structural instability, reduce microcracks and inhibit impedance surge in circulation. Therefore, the combined action of doping elements, bulk phase uniform doping, surface layer directional enrichment, coating layer materials and transition-phase-free in-situ uniform coating can improve the stability of the lithium nickel manganese oxide lattice structure, inhibit electrolyte decomposition, and enable the battery monomer to have better cycle performance at high temperature. In some embodiments, the lithium nickel manganese oxide h