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CN-121983529-A - Composite positive electrode material, preparation method thereof, positive electrode plate, battery pack and electric equipment

CN121983529ACN 121983529 ACN121983529 ACN 121983529ACN-121983529-A

Abstract

The application provides a composite positive electrode material and a preparation method thereof, a positive electrode plate, a battery pack and electric equipment, wherein the composite positive electrode material comprises a positive electrode active material matrix, ion conductor particles and electronic conductor particles; the ion conductor particles and the electron conductor particles are respectively distributed along the surface of the positive electrode active material matrix, wherein at least part of the positive electrode active material matrix and the ion conductor particles are combined through a polar covalent bond. The specific structure of the composite positive electrode material not only can keep the original advantages of the positive electrode active material matrix, but also can effectively improve the ion conductivity and the electron conductivity of the positive electrode active material matrix, so that the all-solid-state battery has higher rate capability, and can keep the advantages of high interface stability and high energy density.

Inventors

  • HAN AIGUO
  • ZHANG LING
  • XU CHAQING

Assignees

  • 比亚迪股份有限公司

Dates

Publication Date
20260505
Application Date
20251029

Claims (14)

  1. 1. The composite positive electrode material is characterized by comprising a positive electrode active material matrix, ion conductor particles and electron conductor particles, wherein the ion conductor particles and the electron conductor particles are respectively distributed along the surface of the positive electrode active material matrix, and at least part of the ion conductor particles are combined with the positive electrode active material matrix through a polar covalent bond.
  2. 2. A composite positive electrode material according to claim 1, wherein the mass fraction of the ion conductor particles in the composite positive electrode material is 0.5-20%, preferably 1-15%, and/or, The mass fraction of the electron conductor particles in the composite positive electrode material is 0.01% -10%, preferably 0.1% -3%.
  3. 3. The composite positive electrode material according to claim 1 or 2, wherein the D50 of the positive electrode active material matrix is 1 μm to 10 μm, and/or, The ion conductor particles have a D50 of 0.05 μm to 1 μm, and/or, The D50 of the electron conductor particles is 0.01 μm to 0.5 μm.
  4. 4. A composite positive electrode material according to any one of claims 1 to 3, wherein the ion conductor particles comprise lithium ion solid state electrolyte, and/or, The electron conductor particles comprise at least one of graphene, acetylene black, carbon nanotubes and carbon black, and/or, The positive electrode active material matrix includes primary particles and/or secondary particles of a positive electrode active material, preferably primary particles.
  5. 5. The composite positive electrode material according to any one of claims 1 to 4, wherein the ion conductor particles comprise a sulfur silver germanium ore type sulfide, preferably the chemical composition of the sulfur silver germanium ore type sulfide is Li 6-x PS 5-x Cl m M n , wherein M is selected from at least one of Sn, br, I, F, x is selected from 0 to 1, M, n, x satisfies m+n-1 = x, and/or, The chemical composition of the positive electrode active material matrix includes at least one of Li 1+z Co 1-n A n O 2 、Li 1+z Ni x Co y M 1-x-y-n A n O 2 、mLi 2 MnO 3 ·(1-m)Li 1+z Ni x Co y Mn 1-x-y-n A n O 2 、Li 1+z Fe x Mn 1-x-n A n PO 4 、Li 1+z Mn 2-n A n O 4 、Li 1+z Fe 1-n A n PO 4 ; wherein z is 0-0.1, n is 0-0.1, x is 0-1, y is 0-1, 0-x+y+n is 1, m is Mn or Al, and A is Ti, mg, al, zr, nb, ba, la, V, W, ag, sn.
  6. 6. A method for producing a composite positive electrode material according to any one of claims 1 to 5, comprising the step of subjecting a mixture comprising a positive electrode active material matrix, electron conductor particles and ion conductor particle precursors to a heat treatment to obtain the composite positive electrode material.
  7. 7. The method according to claim 6, wherein the mass fraction of the ion conductor particle precursor in the mixture is 0.5-20%, preferably 1-15%, and/or, The mass fraction of the electron conductor particles in the mixture is 0.01% -10%, preferably 0.1% -3%.
  8. 8. The method according to claim 6 or 7, wherein the heat treatment is performed at a temperature of 150 to 500 ℃ for a time of 1 to 300min, preferably at a temperature of 250 to 400 ℃ for a time of 10 to 60min.
  9. 9. The method according to any one of claims 6 to 8, wherein the heat treatment is preceded by a sanding treatment of the mixed solution including the ion conductor particle precursor.
  10. 10. The method according to claim 9, wherein the solvent of the mixed solution comprises an aprotic solvent, and/or, The solid content in the mixed solution is 1% -70%, preferably 30% -55%.
  11. 11. A positive electrode sheet comprising the composite positive electrode material according to any one of claims 1 to 5, or the composite positive electrode material obtained by the production method according to any one of claims 6 to 10.
  12. 12. A battery comprising the positive electrode sheet according to claim 11.
  13. 13. A battery comprising at least two cells according to claim 12.
  14. 14. A powered device comprising the battery of claim 12 or the battery pack of claim 13.

Description

Composite positive electrode material, preparation method thereof, positive electrode plate, battery pack and electric equipment Technical Field The application relates to the technical field of batteries, in particular to a composite positive electrode material and a preparation method thereof, a positive electrode plate, a battery pack and electric equipment. Background All-solid-state batteries have become the core technical direction of next-generation power batteries and energy storage systems by virtue of their excellent safety and wide-temperature-range adaptability. However, the poor interfacial compatibility between the current positive electrode material and the solid electrolyte leads to excessive interfacial impedance, which severely restricts the exertion of the overall performance of the battery. To address the above challenges, the current mainstream solution is to coat the particles of the positive electrode material with a solid electrolyte. Although the strategy can improve the stability of the interface ion transmission channel to a certain extent, reduce the interface impedance, the play of the multiplying power performance and the energy density of the battery is inevitably limited. Currently, how to synergistically improve the interfacial stability, rate performance and energy density of all-solid-state batteries remains a key challenge in breakthrough. Disclosure of Invention The application provides a composite positive electrode material, which synergistically improves the interface stability, the multiplying power performance and the energy density of an all-solid-state battery by combining a positive electrode active material matrix, ion conductor particles and electron conductor particles in a specific manner. The application also provides a preparation method for preparing the composite positive electrode material, which has simple process and is suitable for mass production. The application also provides a positive plate which comprises the composite positive material, so that the positive plate has the advantages of high interface stability, high ion and electron transmission efficiency and high energy density. The application also provides a battery comprising the positive plate, so that the battery has the advantages of good cycle performance, high rate capability and high energy density. The application also provides a battery pack which comprises at least two batteries, so that the battery pack has the advantages of good cycle performance, high rate capability and high energy density. The application also provides electric equipment which comprises the battery or the battery pack, so that the electric equipment has the advantages of long standby time and stable output performance. The application provides a composite positive electrode material which comprises a positive electrode active material matrix, ion conductor particles and electron conductor particles, wherein the ion conductor particles and the electron conductor particles are respectively distributed along the surface of the positive electrode active material matrix, and at least part of the ion conductor particles are combined with the positive electrode active material matrix through a polar covalent bond. The mass fraction of the ion conductor particles in the composite positive electrode material is 0.5% -20%, preferably 1% -15%, and/or the mass fraction of the electron conductor particles in the composite positive electrode material is 0.01% -10%, preferably 0.1% -3%. The composite positive electrode material as described above, wherein the D50 of the positive electrode active material matrix is 1 μm to 10 μm, and/or the D50 of the ion conductor particles is 0.05 μm to 1 μm, and/or the D50 of the electron conductor particles is 0.01 μm to 0.5 μm. The composite positive electrode material as described above, the ion conductor particles comprise lithium ion solid state electrolyte, and/or the electron conductor particles comprise at least one of graphene, acetylene black, carbon nanotubes, carbon black, and/or the positive electrode active material matrix comprises primary particles and/or secondary particles, preferably primary particles, of positive electrode active material. The composite positive electrode material comprises sulfur silver germanium ore type sulfide, preferably the chemical composition of the sulfur silver germanium ore type sulfide is Li 6-xPS5-xClmMn, wherein M is selected from at least one of Sn, br, I, F, x is selected from 0-1, M, n and x meets m+n-1=x, and/or the chemical composition of the positive electrode active material matrix comprises at least one of Li1+zCo1-nAnO2、Li1+zNixCoyM1-x-y-nAnO2、mLi2MnO3·(1-m)Li1+zNixCoyMn1-x-y-nAnO2、Li1+zFexMn1-x-nAnPO4、Li1+zMn2-nAnO4、Li1+zFe1-nAnPO4, wherein z is more than or equal to 0.1, n is more than or equal to 0 and less than or equal to 0.1, x is more than or equal to 0 and less than 1, y is more than 0 and less than 1, x+y+n is more than 1,