Search

CN-121990618-A - Li (lithium ion battery)3AlF6Coated ultrahigh nickel ternary lithium ion battery positive electrode material, and preparation method and application thereof

CN121990618ACN 121990618 ACN121990618 ACN 121990618ACN-121990618-A

Abstract

The invention discloses an ultra-high nickel ternary layered lithium ion battery anode material coated by Li 3 AlF 6 , and a preparation method and application thereof. According to the invention, the nickel-cobalt-manganese ternary precursor is mixed with a lithium source, and the ultra-high nickel ternary anode material is obtained through high-temperature calcination. And adding an aluminum source and a fluorine source into the anode material by adopting a wet chemical method, drying, and then completing secondary high-temperature calcination to finally obtain the uniform and stable Li 3 AlF 6 -coated ultrahigh nickel ternary layered anode material. The invention utilizes the residual lithium on the surface of the positive electrode as a lithium source of the Li 3 AlF 6 coating layer, and successfully improves the electrochemical performance of the ultra-high nickel ternary positive electrode material while effectively reducing the residual lithium compound. The uniform and stable Li 3 AlF 6 coating layer prepared by the method can inhibit interface side reaction, alleviate ternary positive electrode structure degradation, prolong the cycle life of the battery, has excellent ionic conductivity, can reduce interface impedance, optimize a lithium ion transmission path and realize synchronous improvement of the cycle stability and the multiplying power performance of the ultra-high nickel ternary layered lithium ion battery positive electrode material.

Inventors

  • SHEN LAIFA
  • HU WENXIN
  • MAO GUIHONG

Assignees

  • 南京航空航天大学

Dates

Publication Date
20260508
Application Date
20251224

Claims (10)

  1. 1. The preparation method of the Li 3 AlF 6 -coated ultrahigh nickel ternary lithium ion battery anode material is characterized in that a nickel cobalt manganese ternary hydroxide precursor is used as a raw material, mixed with a lithium source, subjected to high-temperature solid-phase sintering in flowing oxygen atmosphere, cooled and crushed to obtain an ultrahigh nickel ternary anode substrate material, then dispersed in an absolute ethyl alcohol dispersion liquid containing an aluminum source, sequentially added with a fluorine source, deionized water and an absolute ethyl alcohol mixed solution, mixed, dried to remove a solvent, and subjected to high-temperature calcination again to enable the aluminum source, the fluorine source and residual lithium on the surface of the substrate to react in situ to generate a fast ion conductor Li 3 AlF 6 coating layer, and the Li 3 AlF 6 -coated ultrahigh nickel ternary lithium ion battery anode material is obtained.
  2. 2. The method for preparing the Li 3 AlF 6 coated ultrahigh nickel ternary lithium ion battery positive electrode material according to claim 1, characterized by comprising the following steps: Step 1, uniformly mixing a nickel-cobalt-manganese ternary precursor with LiOH-H 2 O, carrying out sectional calcination in a tubular atmosphere furnace flowing oxygen, firstly preserving heat at 450-550 ℃ for 4-6H, then preserving heat at 700-800 ℃ for 10-15H, finally cooling to 80 ℃ according to 5 ℃ per min, cooling to room temperature along with the furnace, and grinding and sieving to obtain the ultra-high nickel ternary cathode material; Dispersing an aluminum source in an absolute ethyl alcohol solution, stirring for 1-3 h, adding an ultrahigh nickel ternary positive electrode material, stirring for 0.1-0.5: 0.5 h, adding a fluorine source, continuously stirring for 0.1-0.5: 0.5 h, finally adding a mixed solution of deionized water and absolute ethyl alcohol, heating in a water bath at 60-70 ℃ and stirring for 2-3: 3 h, standing at room temperature for a period of time, placing in a vacuum drying oven, drying at 60-70 ℃, then drying at 100-120 ℃ for 10-15: 15 h, grinding and sieving to obtain a primary ultrahigh nickel ternary positive electrode coating material; And 3, carrying out back burning on the primary ultra-high nickel ternary anode coating material in a tubular atmosphere furnace with flowing atmosphere, preserving heat at 350-450 ℃ for 4-6 h ℃, finally cooling to 80 ℃ according to 5 ℃ per min, cooling to room temperature along with the furnace, and grinding and sieving to obtain the Li 3 AlF 6 coated ultra-high nickel ternary lithium ion battery anode material.
  3. 3. The method for preparing the lithium ion battery positive electrode material coated with the ultra-high nickel ternary coated with the Li 3 AlF 6 , according to claim 2, wherein the chemical formula of the nickel-cobalt-manganese ternary precursor in the step 1 is Ni 0.96 Co 0.03 Mn 0.01 (OH) 2 ,Ni 0.96 Co 0.03 Mn 0.01 (OH) 2 and n Li: n (Ni+Co+Mn) in LiOH H 2 O is 1.05:1.
  4. 4. The method for preparing the lithium- 3 AlF 6 -coated ultrahigh-nickel ternary lithium-ion battery positive electrode material according to claim 2, wherein in the step 2, the aluminum source is aluminum isopropoxide, and the fluorine source is at least one of lithium fluoride, ammonium fluoride and aluminum fluoride.
  5. 5. The method for preparing the Li 3 AlF 6 coated ultrahigh nickel ternary lithium ion battery positive electrode material according to claim 2, wherein the mass of the ultrahigh nickel ternary positive electrode material mixed with the aluminum source and the fluorine source in the step 2 is 0.5-1.5 g.
  6. 6. The method for preparing the lithium-ion battery positive electrode material coated with the Li 3 AlF 6 according to claim 2, wherein the back firing atmosphere in the step 3 is at least one of oxygen, argon and nitrogen, and the content of the Li 3 AlF 6 coating layer is 0.25-2%.
  7. 7. The method for preparing the positive electrode material of the ultra-high nickel ternary lithium ion battery according to claim 2, wherein the mesh number of the sieve is 300 mesh after grinding in the steps 1,2 and 3.
  8. 8. The ultra-high nickel ternary lithium ion battery anode material prepared based on the preparation method of claim 1.
  9. 9. The positive electrode material of the ultra-high nickel ternary lithium ion battery according to claim 8, wherein Ni is more than or equal to 0.96 mol, and a diffraction peak of the positive electrode material is an alpha-NaFeO 2 lamellar structure characteristic peak and belongs to a hexagonal system and R-3m space group.
  10. 10. Use of the ultra-high nickel ternary cathode material according to claim 9 as a cathode in a lithium ion battery.

Description

Li 3AlF6 -coated ultrahigh nickel ternary lithium ion battery 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 an ultra-high nickel ternary lithium ion battery anode material coated by Li 3AlF6, and a preparation method and application thereof. Background Under the large background of global energy structure transformation acceleration, an efficient green energy conversion technology is developed, and the realization of efficient utilization of energy has remarkable necessity and practical significance. The lithium ion battery is one of the most promising power battery technologies at present by virtue of the advantages of high energy density, long cycle life, environmental friendliness, wide applicability and the like. The positive electrode material is used as a core component of the lithium ion battery, and the performance of the positive electrode material plays a decisive role in various indexes of the battery. In a mass of positive electrode materials, the ultra-high nickel ternary layered oxide is a popular research object of the positive electrode materials of the lithium ion batteries by virtue of the characteristic of ultra-high specific capacity, but the problems of serious interface side reaction and the like of the positive electrode materials limit practical application. In order to pursue higher energy density, ternary cathode materials have been developed toward ultra-high nickel. However, the increase in nickel content can exacerbate cation mixing, initiate microcrack propagation, and lead to serious interfacial side reactions. Further, HF corrosion of the positive electrode occurs, the surface structure collapses, capacity decay is accelerated, electrolyte is decomposed to generate gases such as O 2、CO2 and the like, thermal runaway is caused, and the battery performance is greatly reduced. Common modification strategies for these problems are elemental doping, gradient structure design, surface cladding, and the like. The surface coating technology can solve the key failure problems of interface side reaction, transition metal dissolution, thermal runaway and the like in a targeted manner on the basis of keeping the theoretical capacity of the material, and meanwhile has the characteristics of simple process, low cost, strong compatibility and the like, and becomes one of the core means for modifying the ultra-high nickel ternary anode material. However, the conventional coating layer has the defect that the ion and electron conduction and the structural stability are difficult to be simultaneously realized, and the development of a novel conductor coating layer becomes a research direction. The Li 3AlF6 coating layer with the ion guide is modified on the surface of the positive electrode material of the ultrahigh nickel ternary lithium ion battery, so that the electrochemical stability of the battery in the charging and discharging process can be ensured, the lithium ion transmission can be optimized, and the multiplying power performance can be improved. CN113161520a discloses a process for forming a nano-alumina protective layer on the surface of a ternary cathode material by a sol-gel method. The method can obtain a uniform alumina coating layer, thereby preventing the electrode from being in direct contact with electrolyte, reducing adverse interface reaction and improving the stability and safety of the ternary positive electrode of the lithium ion battery. However, the coating aluminum oxide adopted by the method belongs to an insulator, is unfavorable for the transmission of lithium ions in the charge and discharge process, and affects the rate capability of the anode. CN117117132a discloses a positive electrode material with cobalt hydroxide, aluminum fluoride and cerium oxide mixed and coated on the surface, which effectively improves the cycle performance of the modified high-nickel positive electrode material. The cobalt hydroxide can react with lithium carbonate on the surface of the positive electrode to reduce the lithium residue on the surface, aluminum fluoride and cerium oxide can inhibit corrosion of HF in circulation, and cerium oxide can be used as a fast ion conductor to improve the electrochemical performance of the positive electrode. However, the method needs a lot of materials, the preparation process is complex, the content of cerium oxide of the fast ion conductor is low, and the effect of optimizing ion transmission is weak. CN114614012B discloses a ternary composite material of in-situ coated fast ion conductor for optimizing interface performance between the positive electrode of all-solid-state battery and solid electrolyte. According to the method, the Li xMyFx+3y coating layer with ion conductivity is constructed, so that electrolyte decomposition side reaction is reduced, meanwhile, transmission of lithium ions is promoted, a