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CN-122025579-A - Modified ternary positive electrode material and preparation method and application thereof

CN122025579ACN 122025579 ACN122025579 ACN 122025579ACN-122025579-A

Abstract

The application provides a modified ternary positive electrode material, a preparation method and application thereof, and relates to the technical field of secondary batteries. The modified ternary positive electrode material comprises a ternary positive electrode base material and a ferroelectric material layer coated on the surface of the ternary positive electrode base material, wherein the chemical formula of the ternary positive electrode base material is LiNi 1‑x‑y Co y Mn x O 2 、LiNi 1‑x‑y Co y Al x O 2 , x is more than or equal to 0.01 and less than or equal to 0.1, y is more than or equal to 0.01 and less than or equal to 0.1, the chemical formula of the ferroelectric material is Ba a Sr 1‑a Ti b M 1‑b O 3 , M is one of Zr and Sn, a is more than or equal to 0.1 and less than or equal to 0.9, and b is more than or equal to 0.1 and less than or equal to 0.9. The modified ternary positive electrode material provided by the application can ensure the capacity retention rate in the high-rate charge-discharge cycle process, and improve the cycle stability of the battery.

Inventors

  • Su Xiejingyu
  • CHEN JIALE
  • LI KEXIN
  • MIAO XIAOWEI

Assignees

  • 苏州工学院

Dates

Publication Date
20260512
Application Date
20260127

Claims (10)

  1. 1. The modified ternary positive electrode material is characterized by comprising a ternary positive electrode base material and a ferroelectric material layer coated on the surface of the ternary positive electrode base material; the chemical formula of the ternary anode matrix material is LiNi 1-x-y Co y Mn x O 2 、LiNi 1-x-y Co y Al x O 2 , wherein x is more than or equal to 0.01 and less than or equal to 0.1, and y is more than or equal to 0.01 and less than or equal to 0.1; The chemical formula of the ferroelectric material is Ba a Sr 1-a Ti b M 1-b O 3 , wherein M is one of Zr and Sn, a is more than or equal to 0.1 and less than or equal to 0.9, and b is more than or equal to 0.1 and less than or equal to 0.9.
  2. 2. The modified ternary cathode material of claim 1, wherein the ferroelectric material layer on the surface of the ternary cathode substrate has a thickness of 30-500 nm a.
  3. 3. The modified ternary cathode material of claim 1, wherein the modified ternary cathode material has an average particle size of 10-20 μιη.
  4. 4. A method for preparing the modified ternary cathode material according to any one of claims 1 to 3, wherein the method comprises the steps of: Dissolving barium salt, strontium salt and complexing agent in water, and adding a thickener to obtain barium-strontium precursor sol; adding the ternary positive electrode matrix material, the ethanol solution of tetrabutyl titanate and the M salt into the barium-strontium precursor sol, mixing, drying and grinding to obtain composite powder; and (3) carrying out high-temperature heat treatment on the composite powder in an inert atmosphere, and cooling to obtain the modified ternary anode material.
  5. 5. The method of producing a modified ternary cathode material according to claim 4, wherein the barium salt comprises at least one of barium nitrate, barium acetate, barium sulfate, and barium chloride, and/or, The strontium salt comprises at least one of strontium nitrate, strontium acetate, strontium sulfate, strontium chloride and strontium oxalate, and/or, The M salt is zirconium salt and tin salt, and/or, The zirconium salt comprises at least one of zirconium nitrate, zirconium carbonate, zirconium sulfate and zirconium chloride, and/or, The tin salt comprises at least one of tin neodecanoate, stannous sulfate and stannous chloride.
  6. 6. The method for producing a modified ternary cathode material according to claim 4, wherein the complexing agent comprises at least one of citric acid, ethylenediamine tetraacetic acid, tartaric acid, malic acid, trisodium citrate, and/or, The thickener comprises at least one of ethylene glycol, glycerol, propylene glycol and butanediol.
  7. 7. The method of preparing a modified ternary positive electrode material according to claim 4, wherein the solid-to-liquid ratio of the ternary positive electrode base material and the barium-strontium precursor sol is 1 (5-10).
  8. 8. The method for preparing a modified ternary cathode material according to claim 4, wherein the high-temperature heat treatment is performed at a temperature of 600-800 ℃ for a time of 2-4 h.
  9. 9. A positive electrode sheet, characterized in that the positive electrode sheet comprises the electrode sheet of claim 1 3 Or the modified ternary positive electrode material prepared by the preparation method of any one of claims 4-8.
  10. 10. A secondary battery comprising the positive electrode tab of claim 9.

Description

Modified ternary positive electrode material and preparation method and application thereof Technical Field The application relates to the technical field of secondary batteries, in particular to a modified ternary positive electrode material, a preparation method and application thereof. Background The lithium ion battery has been widely used in the fields of new energy automobiles, energy storage devices and the like by virtue of the advantages of high energy density, long cycle life and the like. Among the positive electrode materials, high-nickel ternary materials (such as NCM and NCA) have higher specific capacity and working voltage, so that the high-nickel ternary materials become one of the first-choice positive electrode systems for realizing high-energy-density batteries, and particularly Nickel Cobalt Manganese (NCM) ternary materials, and become an important direction for developing and industrialization of the current positive electrode materials of lithium ion batteries. With the increase of nickel content, the ternary material can develop high specific capacity and simultaneously expose a series of problems of structure and chemical stability. In order to improve the thermal stability and electrochemical performance of the high-nickel ternary material, two modification means of element doping and surface coating are mainly adopted at present. The surface coating is a widely applied means, and by constructing a protective coating on the surface of the positive electrode particles, the direct contact between the material and the electrolyte can be effectively reduced, and the dissolution of transition metal and the side reaction of an interface can be inhibited. However, the conventional coating technology mostly adopts conventional metal oxides (such as Al 2O3、TiO2、ZrO2) or simple passivation films, and the coating layers have the following limitations that firstly, the coating uniformity is insufficient, complete and compact full coverage is difficult to realize, secondly, the conductivity of part of coating materials is poor to influence the diffusion and electron transmission of lithium ions, thirdly, the bonding strength between the coating layers and a matrix is limited, stripping easily occurs in the long-cycle process, and the protection effect is gradually lost. Disclosure of Invention The application discloses a modified ternary positive electrode material, a preparation method and application thereof, and aims to solve or alleviate one or more of the technical problems set forth above. In order to achieve the above object, the technical scheme of the present application is as follows: the first aspect of the application provides a modified ternary positive electrode material, which comprises a ternary positive electrode base material and a ferroelectric material layer coated on the surface of the ternary positive electrode base material; the chemical formula of the ternary anode matrix material is LiNi 1-x-yCoyMnxO2、LiNi1-x-yCoyAlxO2, wherein x is more than or equal to 0.01 and less than or equal to 0.1, and y is more than or equal to 0.01 and less than or equal to 0.1; The chemical formula of the ferroelectric material is Ba aSr1-aTibM1-bO3, wherein M is one of Zr and Sn, a is more than or equal to 0.1 and less than or equal to 0.9, and b is more than or equal to 0.1 and less than or equal to 0.9. In combination with the first aspect, preferably, the thickness of the ferroelectric material layer on the surface of the ternary cathode substrate material is 30-500 nm. With reference to the first aspect, preferably, the modified ternary cathode material has an average particle size of 10 to 20 μm. A second aspect of the present application provides a method for preparing the modified ternary cathode material according to the first aspect, the method comprising: Dissolving barium salt, strontium salt and complexing agent in water, and adding a thickener to obtain barium-strontium precursor sol; adding the ternary positive electrode matrix material, the ethanol solution of tetrabutyl titanate and the M salt into the barium-strontium precursor sol, mixing, drying and grinding to obtain composite powder; and (3) carrying out high-temperature heat treatment on the composite powder in an inert atmosphere, and cooling to obtain the modified ternary anode material. Preferably in combination with the second aspect, the barium salt includes at least one of barium nitrate, barium acetate, barium sulfate, and barium chloride; the strontium salt comprises at least one of strontium nitrate, strontium acetate, strontium sulfate, strontium chloride and strontium oxalate; The M salt is zirconium salt and tin salt; the zirconium salt comprises at least one of zirconium nitrate, zirconium carbonate, zirconium sulfate and zirconium chloride; The tin salt comprises at least one of tin neodecanoate, stannous sulfate and stannous chloride. With reference to the second aspect, preferably, the complexing agent