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CN-121974407-A - Nickel-rich ternary positive electrode material and preparation method and application thereof

CN121974407ACN 121974407 ACN121974407 ACN 121974407ACN-121974407-A

Abstract

The invention relates to the technical field of lithium ion batteries, and discloses a nickel-rich ternary positive electrode material, a preparation method and application thereof. The preparation method of the nickel-rich ternary cathode material comprises the following steps of S1, mixing a ternary cathode material precursor with lithium salt, sintering for the first time to obtain an intermediate product, S2, mixing the intermediate product, aluminum salt, pyrophosphoric acid and ethanol to obtain a mixed solution, and S3, drying the mixed solution, sintering for the second time, and cooling to obtain the nickel-rich ternary cathode material. According to the preparation method provided by the invention, the ion transmission layer with high ion conductivity is constructed on the surface of the positive electrode in situ, so that not only is the migration dynamics of Li + improved, but also adverse side reactions at the electrode/electrolyte interface are inhibited, and the capacity and the cycle performance of the nickel-rich ternary positive electrode material under high multiplying power are improved.

Inventors

  • XU KAIHUA
  • LIU CHENFAN
  • CHEN YUJUN
  • MA YONGSONG
  • ZHANG MINGLONG
  • LIU KAIXI
  • SUN HAO
  • GE JIALE

Assignees

  • 格林美（无锡）能源材料有限公司

Dates

Publication Date
20260505
Application Date
20251212

Claims (10)

  1. 1. The preparation method of the nickel-rich ternary positive electrode material is characterized by comprising the following steps of: S1, mixing a ternary positive electrode material precursor with lithium salt, and performing primary sintering to obtain an intermediate product; s2, mixing the intermediate product, aluminum salt, pyrophosphoric acid and ethanol to obtain a mixed solution; And S3, drying the mixed solution, sintering for the second time, and cooling to obtain the nickel-rich ternary anode material.
  2. 2. The preparation method of the nickel-rich ternary cathode material according to claim 1, wherein in the step S1, the ternary cathode material precursor is nickel cobalt manganese hydroxide, optionally, the chemical formula of the nickel cobalt manganese hydroxide is Ni x Co y Mn 1-x-y (OH) 2 , wherein x is more than or equal to 0.5 and less than or equal to 0.9,0.05 and less than or equal to 0.2, and 0< x+y <1 is satisfied.
  3. 3. The method for preparing a nickel-rich ternary cathode material according to claim 1, wherein in step S1, the lithium salt comprises at least one of lithium dihydrogen phosphate, lithium monohydrogen phosphate, lithium hydroxide, lithium carbonate, lithium oxalate, lithium chloride, lithium acetate and lithium phosphate.
  4. 4. The method for producing a nickel-rich ternary positive electrode material according to claim 1 or 2, wherein in step S1, the ratio of the total number of moles of metal elements in the ternary positive electrode material precursor to the number of moles of lithium elements in the lithium salt is 1:1.01 to 1.10.
  5. 5. The method for preparing a nickel-rich ternary cathode material according to claim 1, wherein in the step S1, the first sintering is performed for 4-7 hours at 400-700 ℃ under an oxygen-containing atmosphere, and then the temperature is maintained for 13-15 hours at 600-800 ℃ at a temperature rising rate of 2-5 ℃ per minute; Optionally, the oxygen-containing atmosphere comprises air and/or oxygen.
  6. 6. The method for preparing a nickel-rich ternary cathode material according to claim 1, wherein in the step S2, the mixing is performed by mixing an intermediate product with an ethanol solution containing pyrophosphoric acid and then with an aluminum salt; and/or the aluminum salt comprises aluminum nitrate and/or aluminum sulfate; and/or the dosage ratio of the pyrophosphoric acid to the absolute ethyl alcohol is 5-20:1, and the unit is g to L; And/or the mass ratio of the ternary positive electrode material precursor to the phosphorus element in the pyrophosphoric acid to the aluminum element in the aluminum salt is 1:0.001-0.005:0.001-0.005.
  7. 7. The method for preparing the nickel-rich ternary cathode material according to claim 1, wherein in the step S3, the drying operation is that the ethanol is evaporated at 50-70 ℃ and then vacuum drying is carried out; optionally, the temperature of the vacuum drying is 150-200 ℃, the vacuum degree is 102-105Pa, and the time is 10-15h.
  8. 8. The method for preparing a nickel-rich ternary cathode material according to claim 1, wherein in step S3, the second sintering is performed under an oxygen-containing atmosphere; And/or the temperature of the second sintering is 400-700 ℃ and the time is 4-7h; Optionally, the oxygen-containing atmosphere comprises air and/or oxygen.
  9. 9. The nickel-rich ternary cathode material is characterized in that the nickel-rich ternary cathode material is prepared by the preparation method of the nickel-rich ternary cathode material according to any one of claims 1-8.
  10. 10. The use of the nickel-rich ternary cathode material of claim 9 in the preparation of lithium ion batteries.

Description

Nickel-rich ternary positive electrode material and preparation method and application thereof Technical Field The invention relates to the technical field of lithium ion batteries, in particular to a nickel-rich ternary positive electrode material, a preparation method and application thereof. Background The new energy era has put higher requirements on lithium ion batteries, and the positive electrode material plays an important role in determining electrochemical properties. The ternary positive electrode material is considered as one of ideal candidate materials for current and future power batteries due to the advantages of low cost, environmental friendliness, reversible capacity and the like. In the research progress of the existing positive electrode material, the polycrystalline nickel-rich layered positive electrode material has the outstanding advantage of high energy density. Despite these advantages, their poor rate capability, particularly significant capacity degradation during high rate (> 3C) charge-discharge cycles, places limitations on their wide range of applications in fast charge power batteries and high power applications. This limitation is mainly due to the inherent kinetic barrier and structural instability of nickel-rich cathode materials, mainly due to the high electrode/electrolyte interface impedance, which prevents the formation of an effective ion-conducting network and fails to meet the requirements for rapid Li + migration kinetics at high rates, thus becoming a key factor limiting overall electrode reaction kinetics. In addition, li + is limited in the diffusion coefficient along the two-dimensional channel within the lithium ion structural framework, and the Li layer pitch is contracted in a highly delithiated state, exacerbating the diffusion resistance. The large amount of delithiation causes structural defects such as local lattice distortion and interlayer slip due to irreversible phase transformation, which breaks the continuity of Li + diffusion path, which increases the migration energy barrier and further deteriorates the reaction kinetics and cycle stability. Disclosure of Invention The invention provides a nickel-rich ternary positive electrode material, a preparation method and application thereof, and aims to solve the problems of capacity degradation and poor cycle performance of the nickel-rich positive electrode material under high multiplying power caused by incapability of rapid migration of Li + and unstable structure of the nickel-rich positive electrode material in the prior art. In a first aspect, the invention provides a preparation method of a nickel-rich ternary positive electrode material, which comprises the following steps: S1, mixing a ternary positive electrode material precursor with lithium salt, and performing primary sintering to obtain an intermediate product; s2, mixing the intermediate product, aluminum salt, pyrophosphoric acid and ethanol to obtain a mixed solution; And S3, drying the mixed solution, sintering for the second time, and cooling to obtain the nickel-rich ternary anode material. In an alternative embodiment, in step S1, the ternary cathode material precursor is nickel cobalt manganese hydroxide. In an alternative embodiment, the nickel cobalt manganese hydroxide has the chemical formula Ni xCoyMn1-x-y(OH)2, wherein 0.5≤x≤ 0.9,0.05≤y≤0.2, and satisfies 0< x+y <1. In an alternative embodiment, in step S1, the lithium salt includes at least one of lithium dihydrogen phosphate, lithium hydroxide, lithium carbonate, lithium oxalate, lithium chloride, lithium acetate, and lithium phosphate. In an alternative embodiment, in step S1, the ratio of the total number of moles of metal elements in the ternary cathode material precursor to the number of moles of lithium elements in the lithium salt is 1:1.01-1.10. In an alternative embodiment, in step S1, the first sintering is performed at 400-700 ℃ for 4-7 hours under an oxygen-containing atmosphere, followed by a temperature increase rate of 2-5 ℃ per minute at 600-800 ℃ for 13-15 hours. In an alternative embodiment, the oxygen-containing atmosphere comprises air and/or oxygen. In an alternative embodiment, in step S2, the mixing is performed by mixing the intermediate product with an ethanol solution containing pyrophosphoric acid and then with an aluminum salt. In an alternative embodiment, the aluminum salt comprises aluminum nitrate and/or aluminum sulfate. In an alternative embodiment, the ratio of pyrophosphate to absolute ethanol is in the range of 5 to 20:1 in g to L. In an alternative embodiment, the mass ratio of the ternary positive electrode material precursor to the phosphorus element in the pyrophosphoric acid and the aluminum element in the aluminum salt is 1:0.001-0.005:0.001-0.005. In an alternative embodiment, in step S3, the drying is performed by evaporating ethanol at 50-70 ℃ and then vacuum drying. In an alternative embodiment, the vacuum drying is performed a