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CN-121983568-A - Positive electrode active material, preparation method, positive electrode plate, battery pack and electric equipment

CN121983568ACN 121983568 ACN121983568 ACN 121983568ACN-121983568-A

Abstract

The embodiment of the invention provides an anode active material, a preparation method thereof, an anode plate, a battery pack and electric equipment. The positive electrode active material comprises spherical or spheroidic central particles and a plurality of synapse structures protruding out of the surfaces of the central particles, wherein any two synapses form a groove structure on at least part of the surfaces of the central particles, the positive electrode active material comprises M elements, and the M elements comprise one or more of B, zr, sr, mo, W. The anode active material provided by the embodiment of the invention can improve the ion conduction capacity and the pole piece stability of the battery, thereby improving the rate capability and the capacity retention rate of the solid-state battery.

Inventors

  • WU HUALONG
  • FU QIANG
  • ZHENG XIANGYI
  • YANG ZHIQIANG

Assignees

  • 比亚迪股份有限公司

Dates

Publication Date
20260505
Application Date
20251031

Claims (15)

  1. 1. A positive electrode active material comprising a central particle, and a plurality of synapse structures protruding from a surface of the central particle, at least a portion of adjacent synapses forming a groove structure on at least a portion of the surface of the central particle; The positive electrode active material comprises an M element, and the M element comprises one or more of B, zr, sr, mo, W.
  2. 2. The positive electrode active material according to claim 1, wherein the synapse is integrally formed with the central particle.
  3. 3. The positive electrode active material according to claim 1 or 2, wherein the central particle comprises an aggregate of a plurality of flaky primary particles, at least a part of one ends of the flaky primary particles mutually agglomerate to form the central particle, and at least a part of the other ends of the flaky primary particles form the synapse.
  4. 4. A positive electrode active material according to claim 3, wherein the projection of the synapse onto the surface of the central particle has a width in the range of 10nm to 160nm, preferably 30nm to 50nm; And/or the projection length of the synapse on the surface of the central particle ranges from 50nm to 900nm, preferably from 300nm to 700nm; and/or the height of the synapse ranges from 100nm to 900nm, preferably from 100nm to 400nm; and/or the thickness of the flaky primary particles ranges from 10nm to 160nm, preferably from 30nm to 50nm; and/or the range of the included angle of the length extending direction of at least part of adjacent synapses is 30-85 degrees, preferably 40-75 degrees; and/or, the positive electrode active material includes a ternary positive electrode active material; And/or the average particle diameter of the positive electrode active material is 2 μm to 10 μm, preferably 3 μm to 7 μm.
  5. 5. The positive electrode active material according to claim 4, wherein the included angle ranging from 40 ° to 75 ° is 80% or more in number of all the included angles.
  6. 6. The positive electrode active material according to any one of claims 1 to 5, wherein an atomic ratio a of the M element in the positive electrode active material is 0<a≤0.08.
  7. 7. A method for producing the positive electrode active material according to any one of claims 1 to 6, comprising the steps of: calcining a mixed raw material comprising an active metal source, an M source and a positive electrode active material precursor to obtain the positive electrode active material; The M source comprises one or more of a B source, a Zr source, a Sr source, a Mo source and a W source; the treatment temperature of the calcination treatment is 600-900 ℃.
  8. 8. The method for producing a positive electrode active material according to claim 7, wherein the treatment temperature of the calcination treatment is 680 ℃ to 840 ℃; And/or the treatment time of the calcination treatment is 8-16 h, preferably 10-15 h; and/or the temperature rising rate of the calcination treatment is 1-10 ℃ per minute.
  9. 9. The method for producing a positive electrode active material according to claim 7 or 8, wherein the M source comprises one or more of an oxide containing an M element, a carbonate containing an M element, a oxyhydroxide containing an M element, an oxyacid containing an M element, and preferably the M source comprises H 3 BO 3 and B 2 O 3 .
  10. 10. The method for producing a positive electrode active material according to any one of claims 7 to 9, wherein the average particle diameter of the positive electrode active material precursor is 2 μm to 10 μm, preferably 3 μm to 7 μm.
  11. 11. A positive electrode sheet comprising the positive electrode active material according to any one of claims 1 to 6, or the positive electrode active material produced by the method for producing a positive electrode active material according to any one of claims 7 to 10.
  12. 12. The positive electrode sheet according to claim 11, wherein the positive electrode sheet comprises a solid electrolyte, at least a part of the solid electrolyte is filled in the grooves of the positive electrode active material, Preferably, the solid electrolyte includes at least one of sulfide solid electrolyte and halide solid electrolyte.
  13. 13. A battery comprising the positive electrode sheet according to claim 11 or 12.
  14. 14. A battery comprising at least two cells according to claim 13.
  15. 15. A powered device comprising the battery of claim 13 or the battery pack of claim 14.

Description

Positive electrode active material, preparation method, positive electrode plate, battery pack and electric equipment Technical Field The invention relates to the technical field of batteries, in particular to an anode active material, a preparation method, an anode plate, a battery pack and electric equipment. Background With the rapid increase of the demand of new energy automobiles for high energy density and high safety performance, solid-state batteries are regarded as core technologies of next-generation power batteries due to their incombustibility, wide electrochemical window and compatibility with high-voltage cathode materials. In solid state battery systems, ternary cathode materials (e.g., liNi xCoyMnzO2) are key materials for achieving 500 Wh/kg energy density targets due to their high specific capacity (> 200 mAh/g), wide voltage plateau (3.7-4.3V), and high energy density (> 300 Wh/kg). However, the current solid-state battery still faces the problems of insufficient ionic conductivity and mechanical properties of the pole piece, which results in slow charge transmission dynamics and reduced pole piece stability, thereby causing poor rate capability and continuous increase of interface impedance in the cycling process, and seriously affecting the high rate charge-discharge capability and capacity retention rate. Therefore, there is a need to improve the ion conductivity and pole piece stability of solid state batteries, thereby improving the rate capability and capacity retention of solid state batteries. Disclosure of Invention The invention provides a positive electrode active material, a preparation method thereof, a positive electrode plate, a battery pack and electric equipment, and the ionic conduction capacity and the electrode plate stability of a solid-state battery are improved, so that the multiplying power performance and the capacity retention rate of the solid-state battery are improved. A positive electrode active material comprising a central particle, and a plurality of synapse structures protruding from a surface of the central particle, at least a portion of adjacent synapses forming a groove structure on at least a portion of the surface of the central particle; The positive electrode active material comprises an M element, and the M element comprises one or more of B, zr, sr, mo, W. In some embodiments of the invention, the synapse is integrally formed with the central particle. In some embodiments of the invention, the central particle comprises an agglomeration of a plurality of flaky primary particles, at least a portion of one ends of the flaky primary particles are agglomerated with each other to form the central particle, and at least a portion of the other ends of the flaky primary particles are formed into the synapse. In some embodiments of the present invention, the projection of the synapse on the surface of the central particle has a width ranging from 10nm to 160nm, preferably from 30nm to 50nm; And/or the projection length of the synapse on the surface of the central particle ranges from 50nm to 900nm, preferably from 300nm to 700nm; and/or the height of the synapse ranges from 100nm to 900nm, preferably from 100nm to 400nm; and/or the thickness of the flaky primary particles ranges from 10nm to 160nm, preferably from 30nm to 50nm; and/or the range of the included angle of the length extending direction of at least part of adjacent synapses is 30-85 degrees, preferably 40-75 degrees; and/or, the positive electrode active material includes a ternary positive electrode active material; And/or the average particle diameter of the positive electrode active material is 2 μm to 10 μm, preferably 3 μm to 7 μm. In some embodiments of the present invention, the number of included angles ranging from 40 ° to 75 ° in all the included angles is 80% or more. In some embodiments of the present invention, the atomic ratio a of the M element in the positive electrode active material is 0<a-0.08. The embodiment of the invention also provides a preparation method of the positive electrode active material, which comprises the following steps: calcining a mixed raw material comprising an active metal source, an M source and a positive electrode active material precursor to obtain the positive electrode active material; The M source comprises one or more of a B source, a Zr source, a Sr source, a Mo source and a W source; the treatment temperature of the calcination treatment is 600-900 ℃. In some embodiments of the present invention, the treatment temperature of the calcination treatment is 680 ℃ to 840 ℃; And/or the treatment time of the calcination treatment is 8-16 h, preferably 10-15 h; and/or the temperature rising rate of the calcination treatment is 1-10 ℃ per minute, preferably 3-5 ℃. In some embodiments of the invention, the M source comprises one or more of an oxide containing M element, a carbonate containing M element, a oxyhydroxide containing M element, and an oxy