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CN-122025602-A - Atomic layer deposition LiAlTiO coated modified lithium-rich manganese-based positive electrode material and preparation method thereof

CN122025602ACN 122025602 ACN122025602 ACN 122025602ACN-122025602-A

Abstract

The invention discloses an Atomic Layer Deposition (ALD) LiAlTiO coated modified lithium-rich manganese-based positive electrode material and a preparation method thereof, and belongs to the technical field of lithium battery materials. Aiming at the problems of low initial coulomb efficiency, poor cycle stability and the like of the existing lithium-rich manganese-based anode material, and the defects of single cladding element, insufficient cooperativity of each component and the like of the existing ALD cladding technology, the invention adopts Li 1.2 Mn 0.54 Co 0.13 Ni 0.13 O 2 as a matrix, adopts the ALD technology, selects proper Li source, al source and Ti source, circularly deposits according to the sequence of Li-Al-Ti to form a LiAlTiO composite cladding layer, realizes the atomic-level accurate regulation and control of the thickness of the cladding layer by controlling the number of deposition circles, and carries out annealing treatment on a deposition sample to strengthen the bonding performance of the cladding layer and the matrix. The invention obviously improves the coulomb efficiency and the capacity retention rate of the first circle of the material by the synergistic effect of the three elements, has simple process and strong controllability, is suitable for industrialization, and can be widely applied to the field of high-energy density lithium ion batteries.

Inventors

  • ZHANG GAINI
  • LI XIFEI
  • Yu ruitong
  • XU YUHUI
  • YANG HAOFEI
  • YANG CHENG
  • WEN HAOCHENG

Assignees

  • 西安理工大学

Dates

Publication Date
20260512
Application Date
20260323

Claims (10)

  1. 1. The atomic layer deposition LiAlTiO coated modified lithium-rich manganese-based positive electrode material is characterized in that a lithium-rich manganese-based material is used as a matrix, a LiAlTiO composite coating layer is coated on the surface of the matrix, and the LiAlTiO composite coating layer is an atomic-scale compact film which is formed by cyclic deposition according to the sequence of Li-Al-Ti through an atomic layer deposition technology and contains Li, al, ti, O elements.
  2. 2. The atomic layer deposition liaaltio cladding modified lithium-rich manganese-based positive electrode material according to claim 1, wherein the thickness of the liaaltio composite cladding layer is 1-6 nm, and the material is formed by unit circulation of sequential deposition of Li 2 O、Al 2 O 3 and TiO 2 .
  3. 3. The atomic layer deposition liartio coated modified lithium-rich manganese-based positive electrode material according to claim 1, wherein the chemical formula of the lithium-rich manganese-based material is Li 1.2 Mn 0.54 Co 0.13 Ni 0.13 O 2 .
  4. 4. A method for preparing the atomic layer deposition lialgio coated modified lithium-rich manganese-based positive electrode material according to any one of claims 1 to 3, characterized in that the method comprises the following steps: s1, drying and flatly paving lithium-rich manganese-based material powder in an atomic layer deposition reaction cavity; s2, vacuumizing and purging inert gas are carried out on the reaction cavity, and air, moisture and other impurity gases remained in the cavity are removed; S3, circularly introducing a lithium source precursor, an aluminum source precursor, a titanium source precursor and co-reactant steam into the reaction cavity according to the sequence of Li-Al-Ti, and performing atomic layer deposition on the surface of the substrate to form a LiAlTiO composite coating layer; and S4, annealing the deposited material.
  5. 5. The method according to claim 4, wherein in the step S1, the drying temperature is 120-150 ℃ and the drying time is 2-6 hours, and in the step S2, the vacuum degree of the vacuuming is 10 −3 ～10 −5 Pa, and the vacuuming and purging operations are repeated 3-5 times.
  6. 6. The method according to claim 4, wherein in step S3, each Li-Al-Ti deposition cycle includes one Li 2 O deposition sub-cycle, one Al 2 O 3 deposition sub-cycle, and one TiO 2 deposition sub-cycle, which are sequentially performed, and the total number of Li-Al-Ti deposition cycles is 5 to 20.
  7. 7. The method of claim 6, wherein the step of providing the first layer comprises, The Li 2 O deposition sub-cycle comprises the steps of introducing a lithium source precursor, carrying out adsorption reaction for 5-10 s, purging with inert gas for 40-60 s, introducing steam for reaction for 8-12 s, and purging with inert gas for 40-60 s; The Al 2 O 3 deposition sub-cycle comprises the steps of introducing an aluminum source precursor, carrying out adsorption reaction for 0.2-0.5 s, purging with inert gas for 40-60 s, introducing water vapor for reaction for 8-12 s, and purging with inert gas for 40-60 s; The TiO 2 deposition sub-cycle comprises the steps of introducing a titanium source precursor, carrying out an adsorption reaction for 0.2-0.5 s, purging with inert gas for 40-60 s, introducing water vapor for reacting for 8-12 s, and purging with inert gas for 40-60 s.
  8. 8. The method according to claim 4, wherein in the step S3, the lithium source precursor is selected from one or more of lithium tert-butoxide, lithium isopropoxide and lithium diisopropylamide, the aluminum source precursor is selected from one or more of trimethylaluminum, triisobutylaluminum and tris (dimethylamino) aluminum, and the titanium source precursor is selected from one or more of titanium tetraisopropoxide and titanium tetrachloride.
  9. 9. The method of claim 4, wherein in step S3, the temperature of the reaction chamber for atomic layer deposition is 180-210 ℃.
  10. 10. The method according to claim 4, wherein in step S4, the annealing treatment is performed in an air atmosphere at a temperature rising rate of 2-3 ℃ per minute, an annealing temperature of 550-600 ℃ and a calcination time of 1.5-2.5 h.

Description

Atomic layer deposition LiAlTiO coated modified lithium-rich manganese-based positive electrode material and preparation method thereof Technical Field The invention belongs to the technical field of lithium battery anode materials, and particularly relates to an atomic layer deposition LiAlTiO coated modified lithium-rich manganese-based anode material and a preparation method thereof. Background With the rapid increase of the demand of new energy automobiles and energy storage systems for high-energy density lithium ion batteries, the theoretical specific capacity of the traditional lithium cobalt oxide and nickel cobalt manganese ternary materials is close to the limit value. The lithium-rich manganese-based positive electrode material has a theoretical specific capacity of more than 300 mAh g −1 due to a unique anion/cation synergistic oxidation-reduction mechanism, and is regarded as a core positive electrode material of a next-generation high-energy-density lithium ion battery. However, the lithium-rich manganese-based positive electrode material has the problems of irreversible precipitation of lattice oxygen, easy dissolution and migration of surface transition metal ions, interface side reaction and the like, so that the first-circle coulomb efficiency of the battery is low, the material structure is reconstructed, the voltage attenuation is accelerated, the cycle life is greatly reduced, and the commercialization application of the material is severely restricted. In order to solve the problems, a coating modification strategy is widely adopted in the prior art to protect the surface of the lithium-rich manganese-based positive electrode material. In the conventional coating method, the wet chemical method and the sol-gel method are difficult to realize uniform coverage of a coating layer, a discontinuous island-shaped coating layer is easy to form, the material performance is unstable, the deposition rate is difficult to control, the molten salt auxiliary method can realize uniform coating to a certain extent, but the operation is complex, a large amount of low-melting-point salt is needed, the subsequent washing process is complicated, the accurate regulation and control of an atomic level are difficult to realize, and the Atomic Layer Deposition (ALD) technology is gradually applied to coating modification of a positive electrode material because of the advantages of uniform and compact deposition precision of the atomic level, uniform and compact coating layer, tight combination with a substrate and the like. However, when the ALD technology is used for coating the lithium-rich manganese-based positive electrode material, the prior art mostly adopts single-element or double-element coating, the three problems of lattice oxygen release, transition metal dissolution and interface side reaction are difficult to solve simultaneously by the single-element coating, the synergistic effect of the double-element coating is limited, and the comprehensive improvement of the electrochemical performance of the lithium-rich manganese-based positive electrode material cannot be realized. For example, the patent publication No. CN119143198a (preparation method of multi-coated lithium-rich manganese-based battery positive electrode material and positive electrode material) adopts a strategy of combining wet chemical method and sol-gel method, and has the disadvantages of low coating precision, poor synergy, insufficient process controllability, and the like. The patent with publication number CN113871589A (a lithium-rich manganese-based positive electrode material coated by molten salt auxiliary lithium titanate and a preparation method thereof) adopts molten salt method single lithium titanate coating, and has low coating precision, complex process and no multielement synergistic effect. In addition, in the existing ALD coating process, the binding force between the coating layer and the matrix material is insufficient, the crystallinity is poor, the thickness of the coating layer and the post-treatment process are not optimized, the coating effect is unstable, and the practical application requirement is difficult to meet. Therefore, developing an ALD coating modification method capable of simultaneously solving the above-mentioned defects of the lithium-rich manganese-based cathode material, realizing atomic-level accurate regulation and control, having even and compact coating layers and remarkable synergistic effect of each element becomes a technical problem to be solved in the current field. Disclosure of Invention In view of the problems of low first-circle coulomb efficiency, poor cycle stability and the like of the lithium-rich manganese-based positive electrode material prepared by the prior art, and the technical defects of single coating element, insufficient synergistic effect, unsound combination of a coating layer and a matrix, insufficient process optimization and the like of the prior ALD coa