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CN-122025601-A - Doped coated high-nickel ternary positive electrode material and preparation method and application thereof

CN122025601ACN 122025601 ACN122025601 ACN 122025601ACN-122025601-A

Abstract

The invention provides a doped coated high-nickel ternary cathode material, a preparation method and application thereof, wherein the doped coated high-nickel ternary cathode material comprises a high-nickel ternary cathode material and a lithium metal acid salt coating layer positioned on the surface of the high-nickel ternary cathode material; the high-nickel ternary anode material is doped with a first metal element comprising Ta, and the lithium metal acid salt coating layer comprises a second metal element comprising Nb. The invention synchronously inhibits collapse of a bulk phase structure and interface side reaction under the synergistic effect of molecular-level doping of a metal bulk phase and a lithium metal acid salt coating layer, wherein a first metal element is doped into a high-nickel ternary positive electrode material to occupy a transition metal site to form a first metal element-O bond, so that release of lattice oxygen is inhibited, mixed discharge is reduced, phase transition of the material in a deep charge and discharge process is blocked, the material circulation performance is improved, the lithium metal acid salt coating layer has ion/electron double conduction characteristics, the stability of the interface is ensured, the multiplying power performance is improved, and the blockage of ion migration caused by the traditional inert coating is eliminated.

Inventors

  • XU KAIHUA
  • LEI CHAO
  • ZHANG KUN
  • LI CONG
  • Yue Xianjin

Assignees

  • 荆门市格林美新材料有限公司
  • 格林美股份有限公司

Dates

Publication Date
20260512
Application Date
20260318

Claims (10)

  1. 1. The doped coated high-nickel ternary cathode material is characterized by comprising a high-nickel ternary cathode material and a lithium metal acid salt coating layer positioned on the surface of the high-nickel ternary cathode material; The high-nickel ternary positive electrode material is doped with a first metal element, wherein the first metal element comprises Ta; the lithium metal acid salt coating layer comprises a second metal element, and the second metal element comprises Nb.
  2. 2. The doped coated high nickel ternary positive electrode material of claim 1, wherein the lithium metal acid salt coating layer comprises a first lithium metal acid salt coating layer and a second lithium metal acid salt coating layer; Preferably, the first lithium metal acid salt coating layer is located on the surface of the high nickel ternary positive electrode material, and the second lithium metal acid salt coating layer is located on the surface of the first lithium metal acid salt coating layer.
  3. 3. The doped coated high nickel ternary positive electrode material according to claim 2, wherein the first lithium metal acid salt coating layer is a dense layer; Preferably, the density of the first lithium metal acid salt coating layer is more than or equal to 90%; preferably, the thickness of the first lithium metal acid salt coating layer is 5 nm-8 nm.
  4. 4. The doped coated high nickel ternary positive electrode material according to claim 2, wherein the second lithium metal acid salt coating layer is a porous layer; Preferably, the porosity of the second lithium metal acid salt coating layer is 15% -35%; Preferably, the thickness of the second lithium metal acid salt coating layer is 12 nm-17 nm.
  5. 5. A method for preparing the doped coated high-nickel ternary cathode material according to any one of claims 1-4, wherein the preparation method comprises the following steps: (1) Dispersing the high-nickel ternary precursor in the mixed solution, and carrying out hydrothermal reaction to obtain an intermediate material; wherein the mixed solution comprises a first metal element salt, a second metal element salt, a first lithium source and a solvent; the intermediate material comprises a high-nickel ternary precursor and a lithium metal acid salt coating layer positioned on the surface of the high-nickel ternary precursor; The high-nickel ternary precursor is doped with a first metal element, wherein the first metal element comprises Ta; The lithium metal acid salt coating layer comprises a second metal element, and the second metal element comprises Nb; (2) And (3) uniformly mixing the second lithium source and the intermediate material in the step (1), and calcining to obtain the doped cladding type high-nickel ternary anode material.
  6. 6. The method of claim 5, wherein the high nickel ternary precursor of step (1) has a chemical formula of Ni x Co y Mn 1-x-y (OH) 2 , wherein 0.8 +.x <1,0< y <0.2; Preferably, in the mixed solution in the step (1), the molar ratio of the first metal element salt to the second metal element salt to the first lithium source is (0.5-1.5): (2-4): (4-6); preferably, the molar concentration of the mixed solution is 0.05mol/L to 0.2mol/L.
  7. 7. The method of preparation of claim 5 or 6, wherein the hydrothermal reaction of step (1) comprises a first hydrothermal reaction and a second hydrothermal reaction; Preferably, the total time of the hydrothermal reaction in the step (1) is 8-12 hours; Preferably, the time of the first hydrothermal reaction is 3-5 h; Preferably, after the first hydrothermal reaction is finished, a first lithium metal acid salt coating layer is obtained; preferably, after the second hydrothermal reaction is finished, a second lithium metal acid salt coating layer is obtained; preferably, the temperature of the first hydrothermal reaction and the second hydrothermal reaction are the same; preferably, the temperature of the first hydrothermal reaction and the second hydrothermal reaction is 150 ℃ to 200 ℃.
  8. 8. The production method according to any one of claims 5 to 7, wherein the first metal element salt in step (1) comprises a tantalum salt; Preferably, the second metal element salt of step (1) comprises a niobium salt; Preferably, the first lithium source of step (1) comprises lithium hydroxide.
  9. 9. The method according to any one of claims 5 to 8, wherein the second lithium source in step (2) comprises at least one of lithium hydroxide, lithium nitrate or lithium acetate, preferably lithium hydroxide; Preferably, in the step (2), the molar ratio of the intermediate material to the second lithium source is 1 (1.03-1.05); preferably, the calcining of step (2) comprises a primary calcining and a secondary calcining; preferably, the calcination of step (2) is carried out in an oxygen atmosphere; preferably, the temperature rising rate of the primary calcination in the step (2) is 3-5 ℃ per minute; Preferably, the heat preservation temperature of the primary calcination in the step (2) is 300-500 ℃; preferably, the heat preservation time of the primary calcination in the step (2) is 3-5 h; preferably, the temperature rising rate of the secondary calcination in the step (2) is 2-3 ℃ per minute; preferably, the heat preservation temperature of the secondary calcination in the step (2) is 600-800 ℃; Preferably, the heat preservation time of the secondary calcination in the step (2) is 8-12 h.
  10. 10. A lithium solid-state battery, characterized in that the lithium solid-state battery comprises the doped and coated high-nickel ternary cathode material according to any one of claims 1 to4 or the doped and coated high-nickel ternary cathode material prepared by the preparation method according to any one of claims 5 to 9.

Description

Doped coated high-nickel ternary positive electrode material and preparation method and application thereof Technical Field The invention relates to the technical field of preparation of high-nickel ternary cathode materials, in particular to a doped cladding type high-nickel ternary cathode material, and a preparation method and application thereof. Background With the increasing global demand for sustainable development and clean energy, the wide application of traditional lithium ion batteries in the fields of electric automobiles, renewable energy storage, portable electronic devices and the like faces serious challenges. Although lithium ion batteries have a high energy density (> 250 Wh/kg) and good cycle life (> 1000 times), their flammability (flash point <40 ℃) of the liquid electrolyte, leakage risk and tendency to thermal runaway lead to increasingly prominent safety problems. In addition, the lithium ion battery has the advantages that the interface side reaction is aggravated under the high-temperature (> 60 ℃) environment, the ion conductivity is reduced by more than 80% under the low-temperature (< -20 ℃), and the extreme environment application is severely limited. In order to break through the bottlenecks, the solid-state battery adopts nonflammable inorganic solid-state electrolyte (such as sulfide Li 6PS5 Cl), so that potential safety hazards are fundamentally eliminated, theoretical energy density is improved to be more than 400Wh/kg, and the solid-state battery becomes an ideal choice of a new generation of energy storage technology. Under the background, the nickel-rich ternary positive electrode material (LiNi xCoyMnzO2, x is more than or equal to 0.8) becomes a core material of the solid-state battery by virtue of high specific capacity (200 mAh/g) and cost advantages. However, the industrialization process faces the following barriers that Li ＋/Ni2＋ ions are mixed (the mixed discharge degree is more than 8%) to induce lattice distortion in the deep charge and discharge process, so that the layered structure is anisotropically contracted during the phase transition from H2 to H3 to cause particle microcracks and irreversible capacity attenuation, the interface stability is poor, the residual alkaline compound on the surface of the material is subjected to side reaction with solid electrolyte to generate a high-impedance interface layer, the extreme performance is deteriorated, the transition metal dissolution is accelerated by high-temperature circulation, the lithium ion diffusion system rate is reduced at low temperature, and the circulation stability is insufficient. Aiming at the problems, the optimization is mainly carried out by two technical paths of bulk phase doping and surface coating modification at present, wherein the bulk phase doping occupies lattice sites by introducing elements such as Mg 2＋、Al3＋ and the like, so that the cation mixing degree can be effectively reduced, the phase change is inhibited, the thermal stability is improved, but the side reaction on the surface of the material is difficult to block, and the surface coating modification isolates the direct contact between the anode and the electrolyte by means of an oxide coating (such as Al 2O3、ZrO2), so that the interface side reaction is reduced. However, the existing coating materials generally have double low ion/electron conductivity defects (such as ZrO 2 ion conductivity <10 －10 S/cm, for example), and cannot provide effective channels for lithium ion migration, so that the rate performance is remarkably reduced when the coating layer thickness is increased. For example, CN113594418A discloses a niobium-coated ternary cathode material, which is prepared by dissolving a niobium source and a lithium source, mixing the solution with a ternary precursor, and drying and calcining at a high temperature to form a Li 3NbO4 coating layer. In the technology, although the interfacial side reaction is reduced through surface coating, the coating functional defect exists, the Li 3NbO4 electronic conduction capacity is extremely low, the capacity is obviously attenuated under high multiplying power, and the problem of bulk phase structure collapse is not solved. CN114524360a discloses a low-temperature hydrothermal aluminum doping process, which comprises introducing Al 3＋ into a precursor in a low-temperature hydrothermal environment, and crystallizing at high temperature to obtain a doped material. Although the technology reduces the cation mixing degree, the technology has the defect of insufficient doping depth, al 3＋ is only distributed on the shallow surface layer of the particles, and the interface residual lithium is high due to uncombined coating, so that the improvement of the high-voltage cycle performance is limited. Therefore, the core contradiction of the prior art system is concentrated in three aspects, namely, functional limitation that a single modification means (only doping or only cladding) is