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CN-121983511-A - Positive electrode for all-solid-state battery, preparation method of positive electrode and all-solid-state battery

CN121983511ACN 121983511 ACN121983511 ACN 121983511ACN-121983511-A

Abstract

The embodiment of the application provides an anode for an all-solid-state battery, a preparation method of the anode and the all-solid-state battery. The positive electrode for the all-solid-state battery comprises, by mass, 60-88 parts of an active material, 10-30 parts of a solid electrolyte, 1-5 parts of a conductive agent and 1-5 parts of a binder, wherein the active material comprises at least two particles with different particle diameters, and the solid electrolyte comprises at least two particles with different particle diameters. The positive electrode for the all-solid-state battery adopts a particle size grading scheme, reduces the dependence on solid electrolyte, improves the duty ratio of active substances, optimizes an electrode structure, remarkably enhances the diffusion kinetics of lithium ions and the cycle performance of the battery, realizes double breakthrough of high energy density and high rate performance, and solves the technical problem that the energy density of the all-solid-state battery is difficult to promote.

Inventors

  • XU MEI
  • XIONG WEIQIANG
  • CHEN YULE
  • ZHOU LONGXIANG

Assignees

  • 奇瑞汽车股份有限公司

Dates

Publication Date
20260505
Application Date
20260122

Claims (10)

  1. 1. An all-solid-state battery positive electrode, characterized by comprising, in parts by mass: 60-88 parts of active substances; 10-30 parts of a solid electrolyte; 1-5 parts of a conductive agent; 1-5 parts of a binder; Wherein the active material comprises particles of at least two different particle sizes, and the solid electrolyte comprises particles of at least two different particle sizes.
  2. 2. The positive electrode for an all-solid battery according to claim 1, wherein the active material includes a first particle diameter active material and a second particle diameter active material, and a difference in particle diameter between the first particle diameter active material and the second particle diameter active material is 1 μm to 19.5 μm.
  3. 3. The positive electrode for all-solid-state battery according to claim 2, wherein the first particle diameter active material has a particle diameter of 5 μm to 20 μm, the second particle diameter active material has a particle diameter of 0.5 μm to 4 μm, and/or the mass ratio of the first particle diameter active material to the second particle diameter active material is (7:3) - (9:1).
  4. 4. The positive electrode for an all-solid battery according to claim 3, wherein the solid electrolyte comprises a first particle size electrolyte and a second particle size electrolyte, the difference in particle size between the first particle size electrolyte and the second particle size electrolyte is 0.2 μm to 4.9 μm, and/or the particle size of the first particle size electrolyte is 1 μm to 5 μm, the particle size of the second particle size electrolyte is 0.1 μm to 0.8 μm, and/or the mass ratio of the first particle size electrolyte to the second particle size electrolyte is (6:4) to (8:2).
  5. 5. The positive electrode for an all-solid battery according to any one of claims 1 to 4, wherein the active material is selected from one or more of lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium cobalt oxide, lithium iron phosphate, lithium iron manganese phosphate, and lithium-rich manganese base, and/or the solid electrolyte is selected from one or more of sulfide solid electrolyte, oxide solid electrolyte, halide solid electrolyte, and polymer solid electrolyte.
  6. 6. The positive electrode for an all-solid battery according to any one of claims 1 to 4, wherein the conductive agent is one or more selected from acetylene black, conductive carbon black, carbon nanotubes and graphene, and/or the binder is one or more selected from hydrogenated nitrile rubber, butadiene rubber, natural rubber, polyvinylidene fluoride, styrene-butadiene-styrene triblock copolymer and chlorobenzene rubber.
  7. 7. A method for producing the positive electrode for all-solid battery according to any one of claims 1 to 6, comprising the steps of: Step S1, dry-mixing raw materials comprising active substances, solid electrolyte, conductive agents and binders to obtain mixed dry materials; step S2, adding the mixed dry material into an aprotic organic solvent, and stirring to obtain anode slurry; And step S3, coating the positive electrode slurry on a current collector, and drying and cold pressing to obtain the positive electrode for the all-solid-state battery.
  8. 8. The method according to claim 7, wherein the aprotic organic solvent is one or more selected from the group consisting of xylene, toluene, mesitylene, n-heptane, anisole, butyl butyrate, isobutyl acetate, methylene chloride, dichloroethane, dichloropropane, dibromomethane, and dibromoethane.
  9. 9. The method according to claim 7, wherein in the step S3, the drying process includes a first-stage low-temperature drying process and a second-stage vacuum high-temperature drying process performed sequentially, the temperature of the first-stage low-temperature drying process is 40 ℃ to 60 ℃, the drying time is 1 to 3 hours, the temperature of the second-stage vacuum high-temperature drying process is 80 ℃ to 120 ℃, the drying time is 2 to 6 hours, the vacuum degree is lower than-0.09 Mpa, and the cold pressure of the cold pressing process is 200Mpa to 500 Mpa.
  10. 10. An all-solid-state battery comprising a positive electrode and a negative electrode, wherein the positive electrode is the positive electrode for all-solid-state batteries according to any one of claims 1 to 6, and/or the positive electrode is produced by the production method according to any one of claims 7 to 9.

Description

Positive electrode for all-solid-state battery, preparation method of positive electrode and all-solid-state battery Technical Field The embodiment of the application relates to the technical field of all-solid-state batteries, in particular to an anode for an all-solid-state battery, a preparation method of the anode and the all-solid-state battery. Background Unlike liquid lithium ion batteries, the electrochemical performance of all-solid state batteries is directly dependent on the interfacial contact between the solid electrolyte and the active material and the diffusion of lithium ions in the solid electrolyte. However, it is difficult to form continuous and efficient ion and electron transport paths in the composite positive electrode due to physical characteristics of the solid electrolyte and the active material, such as particle size, distribution, and morphology. Especially under the condition of high-load positive electrode, the volume change of the active material can aggravate the interface contact problem, so that the internal resistance of the battery is increased and the capacity decay is accelerated. In addition, in order to ensure sufficient diffusion of lithium ions, a higher solid electrolyte ratio is generally required in the prior art, which further reduces the loading amount of the cathode material and restricts the improvement of the energy density of the battery. Aiming at the technical problem that the energy density of an all-solid-state battery is difficult to improve, no good solution exists at present. Disclosure of Invention The embodiment of the application provides an anode for an all-solid-state battery, a preparation method thereof and the all-solid-state battery, which at least solve the technical problem that the energy density of the all-solid-state battery is difficult to improve. According to one aspect of the embodiment of the application, the positive electrode for the all-solid-state battery comprises, by mass, 60-88 parts of active substances, 10-30 parts of solid electrolytes, 1-5 parts of conductive agents and 1-5 parts of binders, wherein the active substances comprise at least two kinds of particles with different particle diameters, and the solid electrolytes comprise at least two kinds of particles with different particle diameters. Further, the active material comprises a first particle size active material and a second particle size active material, and the particle size difference between the first particle size active material and the second particle size active material is 1-19.5 μm. Further, the particle size of the first particle size active material is 5-20 μm, the particle size of the second particle size active material is 0.5-4 μm, and/or the mass ratio of the first particle size active material to the second particle size active material is (7:3) - (9:1). Further, the solid electrolyte comprises a first particle size electrolyte and a second particle size electrolyte, wherein the particle size difference between the first particle size electrolyte and the second particle size electrolyte is 0.2-4.9 mu m, and/or the particle size of the first particle size electrolyte is 1-5 mu m, the particle size of the second particle size electrolyte is 0.1-0.8 mu m, and/or the mass ratio of the first particle size electrolyte to the second particle size electrolyte is (6:4) - (8:2). Further, the active material is selected from one or more of lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminate, lithium cobalt oxide, lithium iron phosphate, lithium iron manganese phosphate, and lithium-rich manganese base, and/or the solid electrolyte is selected from one or more of sulfide solid electrolyte, oxide solid electrolyte, halide solid electrolyte, and polymer solid electrolyte. Further, the conductive agent is selected from one or more of acetylene black, conductive carbon black, carbon nanotubes and graphene, and/or the binder is selected from one or more of hydrogenated nitrile rubber, butadiene rubber, natural rubber, polyvinylidene fluoride, styrene-butadiene-styrene triblock copolymer and chlorobenzene rubber. According to another aspect of the embodiment of the application, the preparation method of the positive electrode for the all-solid-state battery comprises the following steps of S1, dry-mixing raw materials including active substances, solid electrolyte, conductive agents and binders to obtain mixed dry materials, S2, adding the mixed dry materials into an aprotic organic solvent to stir to obtain positive electrode slurry, and S3, coating the positive electrode slurry on a current collector, drying and cold-pressing to obtain the positive electrode for the all-solid-state battery. Further, the aprotic organic solvent is selected from one or more of xylene, toluene, mesitylene, n-heptane, anisole, butyl butyrate, isobutyl isobutyrate, benzyl acetate, methylene chloride, dichloroethane, dichloropropane, dibromomethane, and dibromoeth