CN114843503A - Air-stable high-rate nickel-rich layered cathode material and preparation method thereof - Google Patents
Air-stable high-rate nickel-rich layered cathode material and preparation method thereof Download PDFInfo
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- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 title claims abstract description 301
- 229910052759 nickel Inorganic materials 0.000 title claims abstract description 128
- 239000010406 cathode material Substances 0.000 title claims abstract description 99
- 238000002360 preparation method Methods 0.000 title claims abstract description 13
- 239000000463 material Substances 0.000 claims abstract description 53
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 25
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 25
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims abstract description 15
- 229910001416 lithium ion Inorganic materials 0.000 claims abstract description 15
- 150000001875 compounds Chemical class 0.000 claims abstract description 13
- 238000000034 method Methods 0.000 claims abstract description 13
- 229910052783 alkali metal Inorganic materials 0.000 claims abstract description 12
- 150000001340 alkali metals Chemical class 0.000 claims abstract description 9
- 239000002344 surface layer Substances 0.000 claims abstract description 8
- 238000009792 diffusion process Methods 0.000 claims abstract description 5
- 238000001354 calcination Methods 0.000 claims description 70
- 238000010438 heat treatment Methods 0.000 claims description 70
- 238000002156 mixing Methods 0.000 claims description 48
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 claims description 46
- 239000000203 mixture Substances 0.000 claims description 37
- 239000007774 positive electrode material Substances 0.000 claims description 35
- 238000001816 cooling Methods 0.000 claims description 33
- 239000000126 substance Substances 0.000 claims description 33
- 229910052760 oxygen Inorganic materials 0.000 claims description 26
- 238000007873 sieving Methods 0.000 claims description 24
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 23
- 239000001301 oxygen Substances 0.000 claims description 23
- 238000005406 washing Methods 0.000 claims description 22
- 239000012298 atmosphere Substances 0.000 claims description 21
- 238000001035 drying Methods 0.000 claims description 20
- 230000007547 defect Effects 0.000 claims description 17
- 239000002245 particle Substances 0.000 claims description 17
- 238000001914 filtration Methods 0.000 claims description 12
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 10
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 claims description 9
- 229910052782 aluminium Inorganic materials 0.000 claims description 9
- 238000009826 distribution Methods 0.000 claims description 6
- 239000010410 layer Substances 0.000 claims description 6
- 229910052748 manganese Inorganic materials 0.000 claims description 6
- 239000002243 precursor Substances 0.000 claims description 6
- 229910052719 titanium Inorganic materials 0.000 claims description 6
- 229910052721 tungsten Inorganic materials 0.000 claims description 6
- 229910052726 zirconium Inorganic materials 0.000 claims description 6
- 239000002253 acid Substances 0.000 claims description 5
- 150000001342 alkaline earth metals Chemical class 0.000 claims description 5
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 claims description 3
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 3
- 229910013716 LiNi Inorganic materials 0.000 claims description 3
- 229910052791 calcium Inorganic materials 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 3
- 229910052749 magnesium Inorganic materials 0.000 claims description 3
- 229910052700 potassium Inorganic materials 0.000 claims description 3
- 239000011164 primary particle Substances 0.000 claims description 3
- 229910052708 sodium Inorganic materials 0.000 claims description 3
- 238000003860 storage Methods 0.000 abstract description 15
- 230000008569 process Effects 0.000 abstract description 8
- 238000006243 chemical reaction Methods 0.000 abstract description 7
- 230000036961 partial effect Effects 0.000 abstract description 4
- 230000035945 sensitivity Effects 0.000 abstract description 3
- 230000002269 spontaneous effect Effects 0.000 abstract description 3
- 238000009616 inductively coupled plasma Methods 0.000 description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 13
- 239000008367 deionised water Substances 0.000 description 9
- 229910021641 deionized water Inorganic materials 0.000 description 9
- 238000003756 stirring Methods 0.000 description 9
- 238000005303 weighing Methods 0.000 description 8
- 238000012986 modification Methods 0.000 description 7
- 230000004048 modification Effects 0.000 description 7
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 150000002642 lithium compounds Chemical class 0.000 description 6
- 230000003075 superhydrophobic effect Effects 0.000 description 5
- 238000012360 testing method Methods 0.000 description 4
- 238000002441 X-ray diffraction Methods 0.000 description 3
- 239000003513 alkali Substances 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 239000010405 anode material Substances 0.000 description 3
- 229910002091 carbon monoxide Inorganic materials 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 239000011888 foil Substances 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 238000003917 TEM image Methods 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 150000001768 cations Chemical class 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000003411 electrode reaction Methods 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 235000006408 oxalic acid Nutrition 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910013290 LiNiO 2 Inorganic materials 0.000 description 1
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 1
- 239000002033 PVDF binder Substances 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
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- 238000004458 analytical method Methods 0.000 description 1
- 239000012300 argon atmosphere Substances 0.000 description 1
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- 238000001879 gelation Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 230000002209 hydrophobic effect Effects 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
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- 229910001415 sodium ion Inorganic materials 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 229910001428 transition metal ion Inorganic materials 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
- H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
- H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- General Chemical & Material Sciences (AREA)
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- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention discloses a high-rate nickel-rich layered cathode material with stable air and a preparation method thereof. The method improves the valence state of the surface element of the material through the lithium vacancy, inhibits the spontaneous reaction of the material and air, and avoids the generation of residual compounds of surface lithium in the storage process; on the other hand, the high-concentration alkali metal element on the surface layer occupies partial lithium position, so that the surface lattice structure is stabilized, and the alkali metal element has larger ionic radius, so that a lithium ion diffusion channel is expanded; therefore, the nickel-rich layered cathode material prepared by the preparation method simultaneously solves the problem of limitation of air sensitivity and slow dynamics of the material, and has excellent material storage performance and rate capability.
Description
Technical Field
The invention relates to the field of lithium secondary batteries, in particular to a high-rate nickel-rich layered cathode material with stable air and a preparation method thereof.
Background
As LiNiO 2 The nickel-rich layered oxide material of the derivative has the advantages of low cost, high specific capacity, good thermal stability and relatively stable structure, and is one of the most potential anode materials of the lithium ion battery at present. The capacity of nickel-rich cathode materials increases with increasing Ni content, but results in some Ni in the synthesis process 2+ Will migrate to the lithium layer to occupy Li + Forming a cation mixed row. In addition, the nickel-rich layered material can react with H in the air when stored in the air 2 O and CO 2 The interaction is carried out to form LiOH and Li on the surface of the nickel-rich cathode material 2 CO 3 When the content of the alkaline substance remaining in the lithium is more than 80%, the content of the lithium compound remaining therein is greatly increased, and a number of adverse effects are caused, mainly manifested as gelation of the positive electrode material slurry, which causes coating difficulty. And the residual lithium compound on the surface of the material is an electrochemical insulating substance, so that the charge transfer resistance in the electrode reaction process is improved, and the electrochemical performance and the rate performance of the anode material are reduced.
Partial research shows that the nickel-rich layered cathode material can be stored in H state at room temperature 2 With CO in the presence of O 2 Reaction, mainly due to H 2 O and CO in air 2 Reaction to form H 2 CO 3 Causing the pH of water on the surface of the material to decrease, thereby corroding the surface of the material, so that Li + Is easy to leach from the material surface crystal lattice and is combined with weakly acidic CO 3 2- Reaction to LiOH and Li 2 CO 3 . The air sensitivity puts higher requirements on the processing and storage of the nickel-rich material, and the material cost is greatly increased.
At present, washing, surface coating and other methods are often used to remove residual lithium compounds to improve the electrochemical performance of the cathode material, but it is difficult to avoid the formation of residual lithium compounds on the surface of the nickel-rich material during storage. The patent with publication number CN111370684A discloses a method for reducing the content of residual alkali on the surface of a nickel-rich cathode material of a lithium ion battery, which is characterized in that a certain amount of acid or acid derivatives are added into a non-aqueous inactive hydrogen organic solvent to reduce the residual alkali, thereby improving the processability and cycle life of the nickel-rich cathode material of the lithium ion battery, but the air storage performance of the material cannot be guaranteed. The publication number is CN105336927B, which discloses a modified super-hydrophobic material coated nickel-rich cathode material for a lithium ion battery, wherein the modified super-hydrophobic material bridges material particles and modifies the surface of the super-hydrophobic material, so that the hydrophobic and hydrophilic electrolyte properties and the electrical conductivity are improved, and the storage performance of the nickel-rich cathode material is improved. However, the super-hydrophobic material is an electrochemical inert insulator, the surface modification of the super-hydrophobic material has a limited effect on improving the electrochemical performance of the nickel-rich cathode material, and the process is complex and difficult to industrialize.
The problems existing in the prior art are as follows: the material has poor stability in air and is easy to react with H in the storage process 2 O and CO 2 Reaction to produce LiOH and Li 2 CO 3 Waiting for lithium to remain basic; the conventional water washing process can only remove residual alkali in the material preparation process, but cannot inhibit the generation of lithium residual substances in the storage process; the residual lithium compound increases the charge transfer resistance during the electrode reaction, resulting in a decrease in the electrochemical properties and rate capability of the positive electrode material. Therefore, development of a novel nickel-rich cathode material modification process is urgently needed to improve the air stability and electrochemical performance of the cathode material.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides the high-rate nickel-rich layered cathode material with stable air and the preparation method thereof, so that the surface and bulk phase structure of the material are optimized, and the air stability and the electrochemical performance of the material are improved.
In order to solve the technical problems, the invention adopts the technical scheme that:
the air stable high rate nickel-rich layered positive electrode material has lithium vacancy defect in the surface and bulk phase containing alkali metal element or alkali earth metal element X in gradient concentration distribution.
The lithium vacancy defect is a stacking fault, the thickness of the defect layer is less than or equal to 20nm, and the lithium vacancy defect is provided with a lithium ion diffusion channel.
The concentration gradient distribution alkali metal element or alkaline earth metal element X is one of Na, Mg, K and Ca, the content of X is gradually increased from the center of the particle to the surface layer, and the high concentration X of the surface layer occupies part of lithium sites to stabilize the surface lattice structure.
The chemical expression of the high-rate nickel-rich layered cathode material with stable air is Li 1-a X b Ni c M 1-c O 2 M is one or more of Mn, Co, Al, Ti, Zr and W, and 0<a≤0.05，0<b is less than or equal to 0.05, c is more than or equal to 0.8 and less than or equal to 1; the particle diameter d50 is 3-15 μm, the particle diameter of the primary particle is 50-500 nm, and the specific surface area of the material is 0.5-2.0 m 2 G, LiOH content<2500ppm，Li 2 CO 3 Content (wt.)<2500ppm。
The preparation method of the high-rate nickel-rich layered cathode material with stable air comprises the following steps of:
s1, fully mixing the nickel-rich ternary precursor with LiOH to obtain a mixture A;
s2, carrying out sectional roasting, cooling and crushing on the mixture A in an oxygen atmosphere to obtain the LiNi with the chemical formula c M 1-c O 2 The nickel-rich layered cathode material B;
s3, washing, filtering, drying and sieving the nickel-rich layered cathode material B to obtain the cathode material with the chemical formula of Li 1-a Ni c M 1-c O 2 The nickel-rich layered positive electrode material C;
s4, uniformly mixing the nickel-rich layered positive electrode material C and the compound containing X to obtain a mixture D;
s5, roasting the mixture D step by step, cooling and sieving to obtain the compound with the chemical formula of Li 1-a X b Ni c M 1-c O 2 The nickel-rich layered positive electrode material E.
The general formula of the nickel-rich ternary precursor in S1 is Ni c M 1-c (OH) 2 Wherein M is one or more of Mn, Co, Al, Ti, Zr and W, x is more than or equal to 0.8 and less than 1, the particle size d50 in the particles is 2-15 mu M, and the specific surface area is 5-25M 2 (ii)/g; LiOH and Ni c M 1-c (OH) 2 The molar ratio of (1.0-1.08) to 1, wherein the mixing mode is any one of a high-speed mixer, a double-cone mixer, a coulter mixer and a planetary ball mill;
s2, carrying out sectional roasting, wherein the first-step roasting temperature is 300-600 ℃, the heating rate is 1.0-5.0 ℃/min, and the roasting time is 2-8 h; the temperature of the second step of calcination is 600-900 ℃, the heating rate is 1.0-5.0 ℃/min, and the time is 10-20 h.
The washing medium in the S3 is a weak acid solution, the pH value of the solution is 5-7, the mass ratio of the solution to the nickel-rich layered positive electrode material B is 0.5-3: 1, and the washing time is 2-20 min; the drying temperature is 100-300 ℃, and the drying time is 1-10 h.
In S4, the X-containing compound is one of X-containing hydroxide, carbonate, oxalate and bicarbonate, and the molar ratio of the X-containing compound to the nickel-rich layered positive electrode material C is (0.01-0.08): 1.
The step-by-step roasting in S5 is three-step roasting, wherein the first step of roasting is at 300-500 ℃, the heating rate is 1.0-5.0 ℃/min, and the roasting time is 2-8 h; the temperature of the second step of calcination is 700-900 ℃, the heating rate is 1.0-5.0 ℃/min, and the time is 1-4 h; and the temperature of the third step of calcining is 200-400 ℃, the heating rate is 1.0-5.0 ℃/min, and the time is 1-4 h.
The invention has the beneficial effects that: the air-stable high-rate nickel-rich layered cathode material is prepared by adjusting the water washing and gradient doping secondary roasting processes, the defect modification of the surface lithium-containing vacancy and the modification of bulk phase concentration gradient alkali metal elements and alkaline earth metal elements X are realized, the problem of limitation of air sensitivity and slow dynamics of the nickel-rich layered cathode material is solved, and the storage performance and rate performance of the material are improved.
Drawings
FIG. 1 is an XRD pattern of an air-stable, high-rate nickel-rich layered positive electrode material obtained in example 4;
FIG. 2 is a TEM image of the air-stable high-magnification nickel-rich layered cathode material obtained in example 4;
FIG. 3 is a cross-sectional SEM image and EDS analysis of the air-stable, high-magnification nickel-rich layered cathode material obtained in example 4;
FIG. 4 is a graph comparing the rate capability of lithium ion battery tests for the samples of example 4 with comparative example 1 and comparative example 2;
fig. 5 is a plot comparing the lithium ion battery test cycle performance of the samples of example 4 with comparative examples 1 and 2.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a high-rate nickel-rich layered cathode material with stable air, wherein lithium vacancy defects exist on the surface of the material, and a bulk phase contains alkali metal elements or alkaline earth metal elements X in concentration gradient distribution.
Preferably, the lithium vacancy defect is a stacking fault, the thickness of the defect layer is less than or equal to 20nm, and the defect layer is provided with a lithium ion diffusion channel.
Preferably, the alkali metal element or alkaline earth metal element X in the concentration gradient distribution is one of Na, Mg, K and Ca, the content of X is gradually increased from the center of the particle to the surface layer, and the high concentration X of the surface layer occupies part of lithium sites to stabilize the surface lattice structure.
Preferably, the chemical expression of the air-stable high-rate nickel-rich layered cathode material is Li 1-a X b Ni c M 1-c O 2 M is one or more of Mn, Co, Al, Ti, Zr and W, and 0<a≤0.05，0<b is less than or equal to 0.05, c is more than or equal to 0.8 and less than or equal to 1; the particle diameter d50 is 3-15 μm, the particle diameter of the primary particle is 50-500 nm, and the specific surface area of the material is 0.5-2.0 m 2 G, LiOH content<2500ppm，Li 2 CO 3 Content (wt.)<2500ppm。
The invention also provides a preparation method of the high-rate nickel-rich layered cathode material with stable air, which comprises the following steps:
s1, fully mixing the nickel-rich ternary precursor with LiOH to obtain a mixture A;
s2, carrying out sectional roasting, cooling and crushing on the mixture A in an oxygen atmosphere to obtain the LiNi with the chemical formula c M 1-c O 2 The nickel-rich layered cathode material B;
s3, washing, filtering, drying and sieving the nickel-rich layered cathode material B to obtain the cathode material with the chemical formula of Li 1-a Ni c M 1-c O 2 The nickel-rich layered positive electrode material C;
s4, uniformly mixing the nickel-rich layered positive electrode material C and the compound containing X to obtain a mixture D;
s5, roasting the mixture D step by step, cooling and sieving to obtain the compound with the chemical formula of Li 1-a X b Ni c M 1-c O 2 The nickel-rich layered positive electrode material E.
Preferably, the nickel-rich ternary precursor in S1 has the general formula of Ni c M 1-c (OH) 2 Wherein M is one or more of Mn, Co, Al, Ti, Zr and W, x is more than or equal to 0.8 and less than 1, the particle size d50 in the particles is 2-15 mu M, and the specific surface area is 5-25M 2 (ii)/g; LiOH and Ni c M 1-c (OH) 2 The molar ratio of (1.0-1.08) to 1, wherein the mixing mode is any one of a high-speed mixer, a double-cone mixer, a colter mixer and a planetary ball mill;
preferably, the calcination is carried out in S2 in a segmented manner, wherein the calcination temperature in the first step is 300-600 ℃, the heating rate is 1.0-5.0 ℃/min, and the calcination time is 2-8 h; the temperature of the second step of calcination is 600-900 ℃, the heating rate is 1.0-5.0 ℃/min, and the time is 10-20 h.
Preferably, the washing medium in the S3 is a weak acid solution, the pH value of the solution is 5-7, the mass ratio of the solution to the nickel-rich layered positive electrode material B is 0.5-3: 1, and the washing time is 2-20 min; the drying temperature is 100-300 ℃, and the drying time is 1-10 h.
Preferably, the compound containing X in S4 is one of hydroxide, carbonate, oxalate and bicarbonate containing X, and the molar ratio of the compound containing X to the nickel-rich layered positive electrode material C is (0.01-0.08): 1.
Preferably, the step-by-step roasting in S5 is three-step roasting, wherein the first-step roasting temperature is 300-500 ℃, the heating rate is 1.0-5.0 ℃/min, and the roasting time is 2-8 h; the temperature of the second step of calcination is 700-900 ℃, the heating rate is 1.0-5.0 ℃/min, and the time is 1-4 h; and the temperature of the third step of calcining is 200-400 ℃, the heating rate is 1.0-5.0 ℃/min, and the time is 1-4 h.
Example 1
S1, mixing 2000g Ni 0.83 Mn 0.11 Co 0.06 (OH) 2 (d50 is 3.5 μm, specific surface area is 20m 2 Per g) and 915g of LiOH H 2 Mixing the materials evenly by a colter mixer, setting the rotating speed to be 1000r/min and mixing the materials for 40 min;
s2, placing the mixture A in an oxygen atmosphere furnace for two-step calcination, firstly calcining at 500 ℃ for 4h at the heating rate of 3 ℃/min, then heating to 830 ℃ again for calcination for 12h at the heating rate of 3 ℃/min. Cooling along with the furnace after roasting is finished, crushing and sieving the product to obtain a nickel-rich layered positive electrode material B;
s3, dropwise adding HCl into 1500mL of deionized water, adjusting the pH value to 6.5, adding 1500g of nickel-rich layered cathode material B into the solution, stirring and washing for 5min, filtering and drying at 150 ℃ for 4h to obtain nickel-rich layered cathode material C, and determining the chemical formula of the nickel-rich layered cathode material C to be Li by ICP 0.953 Ni 0.822 Mn 0.115 Co 0.063 O 2 ；
S4, weighing 1000g of nickel-rich layered positive electrode material C and 24g of NaOH, and uniformly mixing the materials by a coulter mixer at the rotation speed of 1000r/min for 30min to obtain a mixture D;
s5, placing the mixture D in an oxygen atmosphere furnace for three-step calcination, firstly calcining at 350 ℃ for 4h at the heating rate of 3 ℃/min, then heating to 700 ℃ for calcination for 1h at the heating rate of 3 ℃/min, cooling to 400 ℃ for calcination for 1h, and cooling along with the furnace after the calcination is finished. Crushing and sieving the product to obtain the air-stable high-rate nickel-rich layered cathode material E, and confirming that the chemical formula of the cathode material E is Li through ICP 0.942 Na 0.049 Ni 0.823 Mn 0.112 Co 0.065 O 2 。
Example 2
S1, mixing 2000g Ni 0.85 Mn 0.10 Co 0.05 (OH) 2 (d50 is 5 μm, specific surface area is 18m 2 Per g) and 930g of LiOH H 2 Mixing the O uniformly by a high-speed mixer, setting the rotating speed to be 900r/min, and mixing for 60 min;
s2, placing the mixture A in an oxygen atmosphere furnace for two-step calcination, firstly calcining at 600 ℃ for 5h at the heating rate of 2.5 ℃/min, then heating to 800 ℃ again for 15h at the heating rate of 2.5 ℃/min. Cooling along with the furnace after roasting is finished, crushing and sieving the product to obtain a nickel-rich layered positive electrode material B;
s3, adding HNO dropwise into 1500mL deionized water 3 Adjusting pH to 5.8, adding 1000g of nickel-rich layered cathode material B into the solution, stirring, washing for 15min, filtering, drying at 250 deg.C for 2h to obtain nickel-rich layered cathode material C, and determining by ICP that its chemical formula is Li 0.965 Ni 0.853 Mn 0.102 Co 0.045 O 2 ；
S4, weighing 1000g of nickel-rich layered positive electrode material C and 15g of KOH, and uniformly mixing by using a high-speed mixer at the rotating speed of 900r/min for 50min to obtain a mixture D;
s5, placing the mixture D in an oxygen atmosphere furnace for three-step calcination, firstly calcining at 400 ℃ for 3h at the heating rate of 2 ℃/min, then heating to 750 ℃ for 2h, calcining at the heating rate of 2 ℃/min, cooling to 300 ℃ for 2h, and cooling along with the furnace after finishing. Crushing and sieving the product to obtain the air-stable high-rate nickel-rich layered cathode material E, and confirming that the chemical formula of the cathode material E is Li through ICP 0.961 K 0.028 Ni 0.851 Mn 0.104 Co 0.045 O 2 。
Example 3
S1, mixing 2000g Ni 0.90 Mn 0.06 Co 0.04 (OH) 2 (d50 is 5 μm, specific surface area is 15m 2 Per g) and 945g LiOH H 2 Mixing O uniformly by a double-cone mixer at the rotating speed of 800r/min for 20 min;
s2, placing the mixture A in an oxygen atmosphere furnace for two-step calcination, firstly calcining at 550 ℃ for 6h at the heating rate of 2.5 ℃/min, then heating to 780 ℃ again for calcination for 12h at the heating rate of 2.5 ℃/min. Cooling along with the furnace after roasting is finished, crushing and sieving the product to obtain a nickel-rich layered positive electrode material B;
s3 atAdding oxalic acid dropwise into 1500mL of deionized water, adjusting pH to 6.0, adding 2000g of nickel-rich layered cathode material B into the solution, stirring, washing for 10min, filtering, drying at 150 deg.C for 5h to obtain nickel-rich layered cathode material C, and determining by ICP that its chemical formula is Li 0.958 Ni 0.895 Mn 0.059 Co 0.046 O 2 ；
S4, weighing 1000g of nickel-rich layered positive electrode material C and 20g of NaOH, and uniformly mixing through a double-cone mixer at the rotating speed of 800r/min for 30min to obtain a mixture D;
s5, placing the mixture D in an oxygen atmosphere furnace for three-step calcination, firstly calcining at 350 ℃ for 6h at the heating rate of 2.5 ℃/min, then heating to 700 ℃ for 3h at the heating rate of 2.5 ℃/min, cooling to 350 ℃ for 2h, and cooling along with the furnace after the calcination is finished. Crushing and sieving the product to obtain the air-stable high-rate nickel-rich layered cathode material E, and confirming that the chemical formula of the cathode material E is Li through ICP 0.953 Na 0.043 Ni 0.897 Mn 0.058 Co 0.045 O 2 。
Example 4
S1, mixing 2000g Ni 0.90 Mn 0.05 Co 0.05 (OH) 2 (d50 is 12 μm, specific surface area is 10m 2 /g) and 920g of LiOH H 2 Mixing the materials evenly by a planetary ball mill, setting the rotating speed to be 600r/min, and mixing for 120 min;
s2, placing the mixture A in an oxygen atmosphere furnace for two-step calcination, firstly calcining at 550 ℃ for 6h at the heating rate of 3 ℃/min, then heating to 770 ℃ again for 15h, and heating at the heating rate of 3 ℃/min. Cooling along with the furnace after roasting is finished, crushing and sieving the product to obtain a nickel-rich layered positive electrode material B;
s3, dropwise adding HCl into 1500mL of deionized water, adjusting the pH value to 6.5, adding 1500g of nickel-rich layered cathode material B into the solution, stirring and washing for 15min, filtering and drying at 200 ℃ for 4h to obtain nickel-rich layered cathode material C, and determining the chemical formula of the nickel-rich layered cathode material C to be Li by ICP 0.962 Ni 0.896 Mn 0.053 Co 0.051 O 2 ；
S4, weighing 1000g of nickel-rich layered cathode material C and 40g of NaHCO 3 Uniformly mixing by a planetary ball mill, setting the rotating speed to be 600r/min, and mixing for 100min to obtain a mixture D;
s5, placing the mixture D in an oxygen atmosphere furnace for three-step calcination, firstly calcining at 500 ℃ for 3h at the heating rate of 3 ℃/min, then heating to 800 ℃ for 2h, calcining at the heating rate of 3 ℃/min, cooling to 320 ℃ for 3h, and cooling along with the furnace after the calcination is finished. Crushing and sieving the product to obtain the air-stable high-rate nickel-rich layered cathode material E, and confirming that the chemical formula of the cathode material E is Li through ICP 0.955 Na 0.034 Ni 0.893 Mn 0.055 Co 0.052 O 2 。
Example 5
S1, mixing 2000g Ni 0.92 Mn 0.06 Co 0.02 (OH) 2 (d50 is 10 μm, specific surface area is 12m 2 Per g) and 915g of LiOH H 2 Mixing the O uniformly by a high-speed mixer, setting the rotating speed to be 850r/min, and mixing for 40 min;
s2, placing the mixture A in an oxygen atmosphere furnace for two-step calcination, firstly calcining at 450 ℃ for 5h at the heating rate of 2 ℃/min, then heating to 770 ℃ again for calcining for 10h at the heating rate of 2 ℃/min. Cooling along with the furnace after roasting is finished, crushing and sieving the product to obtain a nickel-rich layered positive electrode material B;
s3, dropwise adding HCl into 1500mL of deionized water, adjusting the pH value to 6.5, adding 2500g of nickel-rich layered cathode material B into the solution, stirring and washing for 10min, filtering and drying at the drying temperature of 250 ℃ for 2h to obtain nickel-rich layered cathode material C, and determining the chemical formula of the nickel-rich layered cathode material C to be Li by ICP (inductively coupled plasma) 0.973 Ni 0.911 Mn 0.066 Co 0.023 O 2 ；
S4, weighing 1000g of nickel-rich layered cathode material C and 25g of Ca (OH) 2 Uniformly mixing the materials by a high-speed mixer, setting the rotating speed to be 850r/min, and mixing for 30min to obtain a mixture D;
s5, placing the mixture D in an oxygen atmosphere furnace for three-step calcination, firstly calcining at 400 ℃ for 5h at the heating rate of 2.5 ℃/min, thenThen heating to 820 ℃ for roasting for 1h, wherein the heating rate is 2.5 ℃/min, cooling to 280 ℃ for roasting for 3h, and cooling along with the furnace after finishing. Crushing and sieving the product to obtain the air-stable high-rate nickel-rich layered cathode material E, and confirming that the chemical formula of the cathode material E is Li through ICP 0.960 Ca 0.038 Ni 0.912 Mn 0.067 Co 0.021 O 2 。
Example 6
S1, mixing 2000g Ni 0.92 Mn 0.04 Co 0.04 (OH) 2 (d50 is 12 μm, specific surface area is 10m 2 Per g) and 930g of LiOH H 2 Mixing the O uniformly by a high-speed mixer, setting the rotating speed to be 900r/min, and mixing for 30 min;
s2, placing the mixture A in an oxygen atmosphere furnace for two-step calcination, firstly calcining at 500 ℃ for 5h at the heating rate of 2.5 ℃/min, then heating to 760 ℃ again for calcining for 12h at the heating rate of 2.5 ℃/min. Cooling along with the furnace after roasting is finished, crushing and sieving the product to obtain a nickel-rich layered positive electrode material B;
s3, adding oxalic acid into 1500mL of deionized water dropwise, adjusting the pH value to 6.5, adding 2000g of nickel-rich layered cathode material B into the solution, stirring and washing for 5min, filtering and drying at 200 ℃ for 4h to obtain nickel-rich layered cathode material C, and determining the chemical formula of the nickel-rich layered cathode material C to be Li by ICP 0.981 Ni 0.918 Mn 0.045 Co 0.037 O 2 ；
S4, weighing 1000g of nickel-rich layered cathode material C and 10g of Mg (OH) 2 Uniformly mixing by a high-speed mixer, setting the rotating speed to be 900r/min, and mixing for 50min to obtain a mixture D;
s5, placing the mixture D in an oxygen atmosphere furnace for three-step calcination, firstly calcining at 450 ℃ for 4h at the heating rate of 2 ℃/min, then heating to 750 ℃ for 3h at the heating rate of 2 ℃/min, cooling to 330 ℃ for 2h, and cooling along with the furnace after the calcination is finished. Crushing and sieving the product to obtain the air-stable high-rate nickel-rich layered cathode material E, and confirming that the chemical formula of the cathode material E is Li through ICP 0.975 Mg 0.020 Ni 0.916 Mn 0.046 Co 0.038 O 2 。
Example 7
S1, mixing 2000g Ni 0.95 Mn 0.04 Co 0.01 (OH) 2 (d50 is 12 μm, specific surface area is 10m 2 /g) and 920g of LiOH H 2 Mixing the materials evenly by a colter mixer, setting the rotating speed to be 900r/min, and mixing for 30 min;
s2, placing the mixture A in an oxygen atmosphere furnace for two-step calcination, firstly calcining at 450 ℃ for 4h at the heating rate of 3 ℃/min, then heating to 750 ℃ again for calcination for 10h at the heating rate of 3 ℃/min. Cooling along with the furnace after roasting is finished, crushing and sieving the product to obtain a nickel-rich layered positive electrode material B;
s3, dropwise adding H into 1500mL deionized water 2 SO 4 Adjusting pH to 6.8, adding 2000g of nickel-rich layered cathode material B into the solution, stirring, washing for 5min, filtering, drying at 250 deg.C for 1h to obtain nickel-rich layered cathode material C, and determining by ICP that its chemical formula is Li 0.961 Ni 0.946 Mn 0.045 Co 0.009 O 2 ；
S4, weighing 1000g of nickel-rich layered positive electrode material C and 20g of KOH, and uniformly mixing the materials by a colter mixer at the rotation speed of 900r/min for 40min to obtain a mixture D;
s5, placing the mixture D in an oxygen atmosphere furnace for three-step calcination, firstly calcining at 450 ℃ for 6h at the heating rate of 4 ℃/min, then heating to 700 ℃ for 2h, calcining at the heating rate of 4 ℃/min, cooling to 350 ℃ for 1h, and cooling along with the furnace after the calcination is finished. Crushing and sieving the product to obtain the air-stable high-rate nickel-rich layered cathode material E, and confirming that the chemical formula of the cathode material E is Li through ICP 0.958 K 0.038 Ni 0.945 Mn 0.046 Co 0.009 O 2 。
FIG. 1 is the XRD pattern of the air-stable high-rate nickel-rich layered cathode material obtained in example 4, and it can be seen from the XRD pattern that the prepared material has a hexagonal layered structure and good crystallinity, I (003) /I (104) >1.2，Li + /Ni 2+ The degree of cation shuffling is low.
FIG. 2 is a TEM image of the air-stable high-magnification nickel-rich layered cathode material obtained in example 4, and it can be seen that stacking faults caused by oxygen vacancies exist on the surface of the material, and the thickness is about 9 nm;
fig. 3 is a cross-sectional SEM image and EDS analysis of the air-stable high-magnification nickel-rich layered cathode material obtained in example 4, and it can be seen from the cross-sectional element content analysis of the air-stable high-magnification nickel-rich layered cathode material that the prepared material has an obvious Na ion concentration gradient, and the Na content gradually increases from the center of the particle to the surface layer.
Comparative example 1
S1, mixing 2000g Ni 0.90 Mn 0.05 Co 0.05 (OH) 2 (d50 is 12 μm, specific surface area is 10m 2 /g) and 920g of LiOH H 2 Mixing the materials evenly by a planetary ball mill, setting the rotating speed to be 600r/min, and mixing for 120 min;
s2, placing the mixture A in an oxygen atmosphere furnace for two-step calcination, firstly calcining at 550 ℃ for 6h at the heating rate of 3 ℃/min, then heating to 770 ℃ again for 15h, and heating at the heating rate of 3 ℃/min. Cooling along with the furnace after roasting is finished, crushing and sieving the product to obtain a nickel-rich layered positive electrode material B;
s3, adding 1500g of nickel-rich layered cathode material B into 1500mL of deionized water, stirring, washing for 5min, filtering, drying at 150 ℃ for 4h to obtain nickel-rich layered cathode material C, and determining that the chemical formula is Li by ICP 1.006 Ni 0.902 Mn 0.052 Co 0.046 O 2 ；
S4, weighing 1000g of nickel-rich layered cathode material C and 40g of NaHCO 3 Uniformly mixing by a planetary ball mill, setting the rotating speed to be 600r/min, and mixing for 100min to obtain a mixture D;
s5, placing the mixture D in an oxygen atmosphere furnace for three-step calcination, firstly calcining at 500 ℃ for 3h at the heating rate of 3 ℃/min, then heating to 800 ℃ for calcination for 2h at the heating rate of 3 ℃/min, cooling to 320 ℃ for calcination for 3h, and cooling along with the furnace after the calcination is finished. Crushing and sieving the product to obtain a nickel-rich layered cathode material E, and confirming that the chemical formula of the nickel-rich layered cathode material E is Li through ICP 1.003 Na 0.032 Ni 0.901 Mn 0.048 Co 0.051 O 2 。
Comparative example 2
S1, mixing 2000g Ni 0.90 Mn 0.05 Co 0.05 (OH) 2 (d50 is 12 μm, specific surface area is 10m 2 /g) and 920g of LiOH H 2 Mixing the materials evenly by a planetary ball mill, setting the rotating speed to be 600r/min, and mixing for 120 min;
s2, placing the mixture A in an oxygen atmosphere furnace for two-step calcination, firstly calcining at 550 ℃ for 6h at the heating rate of 3 ℃/min, then heating to 770 ℃ again for 15h, and heating at the heating rate of 3 ℃/min. Cooling along with the furnace after roasting is finished, crushing and sieving the product to obtain a nickel-rich layered positive electrode material B;
s3, dropwise adding HCl into 1500mL of deionized water, adjusting the pH value to 6.5, adding 1500g of nickel-rich layered cathode material B into the solution, stirring and washing for 15min, filtering and drying at 200 ℃ for 4h to obtain nickel-rich layered cathode material C, and determining the chemical formula of the nickel-rich layered cathode material C to be Li by ICP 0.963 Ni 0.894 Mn 0.052 Co 0.054 O 2 ；
S4, placing the nickel-rich layered positive electrode material C in an oxygen atmosphere furnace for three-step calcination, firstly calcining at 500 ℃ for 3h at the heating rate of 3 ℃/min, then heating to 800 ℃ for 2h at the heating rate of 3 ℃/min, cooling to 320 ℃ for 3h, and cooling along with the furnace after the temperature is up. Crushing and sieving the product to obtain the air-stable high-rate nickel-rich layered cathode material E, and confirming that the chemical formula of the cathode material E is Li through ICP 0.958 Ni 0.896 Mn 0.050 Co 0.054 O 2 ；
The nickel-rich layered positive electrode materials of examples 1 to 7 and comparative examples 1 to 2 were stored under exposure in a room temperature environment (temperature:. about.25 ℃ C., humidity:. about.50%) and the pH value, the LiOH content and the Li content of the materials before and after 15 days of storage were compared 2 CO 3 Content, and electrochemical performance.
The materials of the above examples and comparative examples were tested for electrochemical performance in lithium ion coin cells.
Lithium ionThe specific manufacturing method of the battery and the positive pole piece thereof comprises the following steps: mixing the prepared anode material powder with acetylene black and polyvinylidene fluoride according to the mass ratio of 8:1:1, adding a proper amount of N-methyl pyrrolidone serving as a dispersing agent, and grinding into slurry; uniformly coating the slurry on an aluminum foil, drying the aluminum foil for 10 hours at 120 ℃ in vacuum, rolling the dried pole piece by using a roll-to-roll machine, cutting the aluminum foil by using a slicing machine into a circular pole piece with the diameter of 1.3cm, and controlling the loading capacity of an active material to be 12mg cm -2 Left and right. Assembling a half cell in an argon atmosphere glove box, wherein the water partial pressure is less than or equal to 0.1ppm, and the oxygen partial pressure is less than or equal to 0.1 ppm; using metal lithium as a counter electrode and 1M LiPF 6 The (EC/DEC/DMC, volume ratio is 1:1:1) solution is used as electrolyte, a CR2032 type button cell is assembled, and the charge and discharge are carried out under the condition of room temperature by using a constant current charge and discharge mode, wherein the voltage range is 2.5-4.25V, and the current density is 40mA/g (0.2C multiplying power) for 100 cycles of charge and discharge circulation. The current density of the battery multiplying power performance test is 40mA/g, 400mA/g, 1000mA/g and 1600mA/g, which respectively correspond to 0.2C, 2C, 5C and 8C.
Collected pH values, LiOH contents, and Li before and after storage of the nickel-rich layered positive electrode materials in examples 1 to 7 and comparative examples 1 to 2 2 CO 3 The contents are shown in table 1:
TABLE 1
The collected first cycle specific charge capacity, first cycle specific discharge capacity, first cycle coulombic efficiency and capacity retention rate after 100 cycles of the lithium ion battery test before and after the storage of the nickel-rich layered positive electrode materials in examples 1 to 7 and comparative examples 1 to 2 are shown in table 2:
TABLE 2
The rate performance data collected for the lithium ion battery tests of the nickel-rich layered positive electrode materials of examples 1-7 and comparative examples 1-2 are shown in table 3:
TABLE 3
In conclusion, the air-stable high-rate nickel-rich layered cathode material improves the storage characteristics and rate performance of the material by surface lithium vacancy defect modification and bulk concentration gradient alkali metal and alkaline earth metal element X doping modification. After 30 days of storage at room temperature, the residual lithium compounds on the surface of the materials of the samples of the examples are obviously lower than those of the samples of the comparative examples, the electrochemical performances before and after storage are not obviously different, and the cycle performance of the materials of the comparative examples is seriously attenuated. In addition, rate performance tests under different current densities of 0.2C to 8C show that the capacity retention rate (8C discharge capacity/0.2C discharge capacity) of the samples in the examples is still more than 80% at 8C high rate, which is much higher than that of the samples in the comparative examples. The lithium vacancy defect is stacking fault, has a good lithium ion diffusion channel, improves the valence state of surface elements of the material, and inhibits the spontaneous reaction of the material and air.
According to the invention, firstly, the lithium vacancy defect introduced on the surface of the material is treated by water washing, so that the valence state of adjacent transition metal ions can be increased, the oxidation resistance of the material is improved, and unfavorable spontaneous reaction between the material and air is inhibited. Secondly, the surface stability and the bulk phase stability of the material are further improved by the gradient doping of alkali metal and alkaline earth metal element X. The alkali metal and alkaline earth metal elements X with higher surface concentration occupy part of lithium sites to play a role of a strut, so that the interface stability is improved, and meanwhile, the lattice spacing of the layered material is expanded due to larger ionic radius, so that the rapid transmission of lithium ions is facilitated, and the multiplying power performance is improved.
The points to be finally explained are: although the present invention has been described in detail with reference to the general description and the specific embodiments, on the basis of the present invention, the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. An air-stable high-rate nickel-rich layered cathode material is characterized in that lithium vacancy defects exist on the surface of the cathode material, and a bulk phase contains alkali metal elements or alkaline earth metal elements X in concentration gradient distribution.
2. The air-stable high-rate nickel-rich layered cathode material of claim 1, wherein the lithium vacancy defects are stacking faults, the thickness of the defect layer is less than or equal to 20nm, and the defect layer has a lithium ion diffusion channel.
3. The air-stable high-rate nickel-rich layered cathode material as claimed in claim 1, wherein the concentration gradient distribution of the alkali metal element or alkaline earth metal element X is one of Na, Mg, K and Ca, the content of X is gradually increased from the center of the particle to the surface layer, and the surface layer high concentration X occupies part of lithium sites to stabilize the surface lattice structure.
4. The air-stable high-rate nickel-rich layered cathode material of claim 1, wherein the chemical expression of the air-stable high-rate nickel-rich layered cathode material is Li 1-a X b Ni c M 1-c O 2 M is one or more of Mn, Co, Al, Ti, Zr and W, and 0<a≤0.05，0<b is less than or equal to 0.05, c is less than or equal to 1 and is less than or equal to 0.8, the particle size d50 is 3-15 mu m, the particle size of primary particles is 50-500 nm, and the specific surface area of the material is 0.5-2.0 m 2 G, LiOH content<2500 ppm，Li 2 CO 3 Content (wt.)<2500 ppm。
5. The preparation method of the air-stable high-rate nickel-rich layered cathode material according to any one of claims 1 to 4, characterized by comprising the following steps:
s1, fully mixing the nickel-rich ternary precursor with LiOH to obtain a mixture A;
s2, carrying out sectional roasting, cooling and crushing on the mixture A in an oxygen atmosphere to obtain the LiNi with the chemical formula c M 1-c O 2 The nickel-rich layered cathode material B;
s3, washing, filtering, drying and sieving the nickel-rich layered cathode material B to obtain the cathode material with the chemical formula of Li 1-a Ni c M 1-c O 2 The nickel-rich layered positive electrode material C;
s4, uniformly mixing the nickel-rich layered positive electrode material C and the compound containing X to obtain a mixture D;
s5, roasting the mixture D step by step, cooling and sieving to obtain the compound with the chemical formula of Li 1-a X b Ni c M 1-c O 2 The nickel-rich layered positive electrode material E.
6. The method for preparing the air-stable high-rate nickel-rich layered cathode material as claimed in claim 5, wherein the general formula of the nickel-rich ternary precursor in S1 is Ni c M 1-c (OH) 2 Wherein M is one or more of Mn, Co, Al, Ti, Zr and W, x is more than or equal to 0.8 and less than 1, the particle size d50 in the particles is 2-15 mu M, and the specific surface area is 5-25M 2 (ii)/g; LiOH and Ni c M 1-c (OH) 2 The molar ratio of (1.0-1.08) to 1, and the mixing mode is any one of a high-speed mixer, a double-cone mixer, a coulter mixer and a planetary ball mill.
7. The preparation method of the air-stable high-rate nickel-rich layered cathode material according to claim 5, wherein the step S2 is a step of roasting, wherein the first step of roasting is performed at a temperature of 300-600 ℃, the temperature rise rate is 1.0-5.0 ℃/min, and the roasting time is 2-8 h; the temperature of the second step of calcination is 600-900 ℃, the heating rate is 1.0-5.0 ℃/min, and the time is 10-20 h.
8. The preparation method of the air-stable high-magnification nickel-rich layered cathode material as claimed in claim 6, wherein the washing medium in S3 is a weak acid solution, the pH value of the solution is 5-7, the mass ratio of the solution to the nickel-rich layered cathode material B is 0.5-3: 1, and the washing time is 2-20 min; the drying temperature is 100-300 ℃, and the drying time is 1-10 h.
9. The method for preparing the air-stable high-rate nickel-rich layered cathode material according to claim 5, wherein the X-containing compound in S4 is one of X-containing hydroxide, carbonate, oxalate and bicarbonate, and the molar ratio of the X-containing compound to the nickel-rich layered cathode material C is (0.01-0.08): 1.
10. The preparation method of the air-stable high-rate nickel-rich layered cathode material as claimed in claim 5, wherein the step-by-step calcination in S5 is three-step calcination, wherein the calcination temperature in the first step is 300-500 ℃, the temperature rise rate is 1.0-5.0 ℃/min, and the calcination time is 2-8 h; the temperature of the second step of calcination is 700-900 ℃, the heating rate is 1.0-5.0 ℃/min, and the time is 1-4 h; and the temperature of the third step of calcining is 200-400 ℃, the heating rate is 1.0-5.0 ℃/min, and the time is 1-4 h.
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