CN112186155A - Coating modified high-nickel cathode material and preparation method and application thereof - Google Patents

Coating modified high-nickel cathode material and preparation method and application thereof Download PDF

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CN112186155A
CN112186155A CN202011017484.2A CN202011017484A CN112186155A CN 112186155 A CN112186155 A CN 112186155A CN 202011017484 A CN202011017484 A CN 202011017484A CN 112186155 A CN112186155 A CN 112186155A
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nickel
coating
sintering
aluminum
lithium
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袁晶
曾汉民
武露露
何巍
祝媛
***
刘金成
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Huizhou Yiwei Energy Battery Co ltd
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Huizhou Yiwei Energy Battery Co ltd
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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
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • 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
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/46—Alloys based on magnesium or aluminium
    • H01M4/463—Aluminium based
    • 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
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • 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
    • 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
    • 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

Abstract

The invention relates to a coating modified high-nickel anode material and a preparation method and application thereof, wherein the preparation method comprises the steps of adding urea into a mixed solution of an aluminum source solution and a high-nickel precursor dispersion liquid, so that Al is uniformly precipitated and attached to the surface of a high-nickel precursor in the form of aluminum hydroxide, then pre-sintering to realize uniform coating of the high-nickel precursor by aluminum oxide, and then preparing lithium and sintering to obtain the coating modified high-nickel anode material; the preparation method takes urea as a precipitator, improves uniform reaction environment for precipitation reaction, is convenient to generate uniform coating layers, and carries out alumina coating on a high-nickel precursor in advance before lithium is prepared, the alumina can penetrate into the surface layer of the material and deep lattice gaps of the material on the surface during sintering to modify the surface, so that the coating is tighter, and further, the stability of the coating modified high-nickel cathode material is improved.

Description

Coating modified high-nickel cathode material and preparation method and application thereof
Technical Field
The invention belongs to the field of battery materials, and relates to a coating modified high-nickel cathode material, and a preparation method and application thereof.
Background
The requirement of the power battery on high energy density promotes the development of high nickel materials, lithium-rich manganese-based materials, lithium-sulfur batteries, lithium-air batteries and the like, but is limited by the technical level, the high nickel materials are widely applied at present, the high nickel materials often have the defects of poor cyclicity, low thermal stability, low safety and the like, mixed discharge of cations is easy to occur due to the self-rich nickel, and the serious dissolution of transition metal ions in the use process of the materials leads to the deterioration of the structural stability of the materials and a series of problems of batteries, such as increase of internal resistance, over-quick capacity attenuation and the like.
Based on the problems of the high nickel material, the material can be modified, including doping and coating, the doping can stabilize the structure of the material, and the surface coating can inhibit the dissolution of transition metal elements in the charging and discharging processes of the material, so that the deposition reduction of the transition metal on a negative electrode and the damage to a negative electrode SEI film are reduced, the consumption of the repair of the SEI film on positive electrode active lithium ions is reduced, the surface characteristic of the positive electrode material is improved, the direct contact between the material and an electrolyte is avoided or reduced, and the occurrence of side reactions between the electrolyte and the positive electrode material is reduced.
The conventional material synthesis process is to coat a layer of inorganic salt, oxide or fluoride on the surface of the high-nickel material by a solid phase method or a liquid phase method.
CN104638227A discloses a modification method of a lithium ion battery anode material, which takes aluminum salt or zirconium salt with low melting point as an alkali treatment agent, uniformly mixes the alkali treatment agent with the lithium ion battery anode material with high pH value, and adopts a two-stage sintering process to obtain a final product. The method effectively reduces residual lithium and pH, but the uniformity of coating is difficult to ensure due to physical mixing. CN109244407A discloses a method for coating a nickel cobalt lithium manganate positive electrode material by blending magnesium oxide and aluminum oxide, wherein the nickel cobalt lithium manganate material is treated by blending magnesium ion solution and aluminum ion solution with magnesium oxide and aluminum oxide, so that a nickel cobalt lithium manganate material coated by magnesium oxide and aluminum oxide together can be formed, the circulation stability of the nickel cobalt lithium manganate material is improved, the performance of the nickel cobalt lithium manganate positive electrode material is improved, but an alcohol solvent is used in the coating process, and the storage and use of an alcohol raw material are involved in large-scale production, so that potential safety hazards exist in the process.
Therefore, the development of a preparation method of the high-nickel cathode material which is simple and safe to operate and low in cost and has long cycle, high safety and high thermal stability is still significant.
Disclosure of Invention
The invention aims to provide a coating modified high-nickel anode material and a preparation method and application thereof, wherein the preparation method comprises the steps of adding urea into a mixed solution of an aluminum source solution and a high-nickel precursor dispersion liquid, so that Al is uniformly precipitated and attached to the surface of a high-nickel precursor in the form of aluminum hydroxide, then pre-sintering to realize uniform coating of the high-nickel precursor by aluminum oxide, and then preparing lithium and sintering to obtain the coating modified high-nickel anode material; the preparation method takes urea as a precipitator, improves uniform reaction environment for precipitation reaction, is convenient to generate uniform coating layers, and carries out alumina coating on a high-nickel precursor in advance before lithium preparation, the alumina can penetrate into the surface layer and deep part of the material during sintering to fill in lattice gaps of the material, so as to modify the surface, so that the coating is more compact, and further the stability of the coating modified high-nickel cathode material is improved.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a preparation method of a coating-modified high-nickel cathode material, including the following steps:
(1) mixing an aluminum source solution with a dispersion liquid of a high-nickel precursor to obtain a mixed solution;
(2) adding urea into the mixed solution obtained in the step (1), and heating for reaction;
(3) and (3) presintering the solid product obtained in the step (2), preparing lithium, and sintering to obtain the coating modified high-nickel cathode material.
According to the method, before lithium is prepared, the precursor of the high-nickel anode material is coated with the alumina, so that the alumina can penetrate into the surface layer and deep parts of the material in the subsequent sintering process to fill the crystal lattice gaps of the material, the surface is modified, the coating is tighter, and the stability of the obtained coated and modified high-nickel anode material is improved.
The advantage of using urea as precipitant in the process according to the invention is that urea does not react immediately with the aluminium source, but through a slow chemical reaction: (NH)2)2CO+3H2O→CO2+2NH4 ++2OH-Uniform release of OH-With other precipitating agents (e.g. NH)3·H2O) to CO (NH)2)2The precipitant can provide a uniform reaction environment without pH gradient, thereby generating a uniform coating layer and further improving the stability of the obtained coating modified high-nickel cathode material.
Meanwhile, the method firstly carries out liquid phase coating on the high nickel precursor, then presintering, lithium preparation and sintering are carried out, and the coating modified high nickel anode material can be obtained; the preparation method is simple and safe to operate and low in cost.
Preferably, the source of aluminium in step (1) comprises aluminium nitrate.
Preferably, the chemical formula of the high nickel precursor in step (1) is NixCoyMnz(OH)2Wherein x is selected from 0.6 to 1, such as 0.7, 0.8 or 09, etc., x + y + z ═ 1.
Preferably, the aluminum source solution in step (1) is added in an amount such that the mass percentage of the aluminum oxide converted from the aluminum source solution is 0.1% to 0.8%, for example, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, or 0.7%, and preferably 0.3% to 0.5%, based on 100% of the mass of the high-nickel precursor.
Preferably, the ratio of the molar amount of urea added in step (2) to the molar amount of aluminium source in step (1) is (14-16: 1, e.g. 14.5:1, 15:1 or 15.5:1, etc.
The molar amount of the aluminum source herein is based on the molar amount of the aluminum element in the aluminum source.
According to the invention, the addition amount of the urea is controlled so that the molar weight ratio of the urea to the aluminum source meets the range, the aluminum source is favorably and uniformly precipitated on the surface of the high-nickel precursor, so that a uniform coating layer is formed, alumina is favorably permeated to the surface layer and deep parts of the material in the subsequent sintering process to fill the crystal lattice gaps of the material, the surface is modified, the coating is more compact and stable, and the stability of the material is improved. When the molar ratio of the two is too small, the coating effect is poor, the improvement of the cycle performance is not obvious, and when the molar ratio of the two is too large, the coating layer is too thick, and the gram capacity exertion of the final material is influenced.
Preferably, the temperature of the heating reaction in step (2) is 50 to 85 ℃, such as 55 ℃, 60 ℃, 65 ℃, 70 ℃ or 75 ℃ and the like.
In the process of the surface coating reaction of the high-nickel precursor, the reaction temperature is limited within the range, which is beneficial to the uniform precipitation of aluminum hydroxide, so that a uniform coating layer is formed, the aluminum oxide can penetrate into the surface layer of the material and the lattice gaps of the material deeply on the surface in the later sintering process, the surface is modified, the coating is more compact, and the stability of the material is improved; when the temperature of the heating reaction is too low, namely less than 50 ℃, the reaction rate is too slow, so that the reaction time is long, the efficiency of the coating process is low, and when the temperature of the heating reaction is too high, namely more than 85 ℃, the reaction rate is too fast, so that the generated aluminum hydroxide cannot be uniformly coated on the surface of the precursor in time.
Preferably, the heating reaction time in the step (2) is 3-5h, such as 3.5h, 4h or 4.5 h.
Preferably, the heating reaction in step (2) is completed by solid-liquid separation, washing and drying.
Preferably, the temperature of the pre-sintering in the step (3) is 300-600 ℃; for example, 350 ℃, 400 ℃, 450 ℃, 500 ℃, 550 ℃ or the like.
According to the invention, the pre-sintering process enables the surface of the high-nickel precursor to form a uniform alumina coating layer, and then the alumina coating layer is mixed with a lithium source to match lithium and doped, and the alumina penetrates into the surface layer and deep parts of the material in the sintering process to fill the crystal lattice gaps of the material, so that the surface is modified, the coating is more compact, and the stability of the material is favorably improved. When the pre-sintering junction temperature is too high, namely more than 600 ℃, the coating effect is influenced, so that the cycle performance is not obviously improved, and the processing cost is high; when the pre-sintering temperature is too low, namely less than 300 ℃, aluminum hydroxide generated on the surface of the precursor cannot be effectively converted into aluminum oxide, and the coating effect is influenced, so that the improvement of the cycle performance and the material stability is not obvious.
Preferably, the pre-sintering time in step (3) is 4-15h, such as 5h, 8h, 10h, 12h or 14 h.
Preferably, the atmosphere of the pre-sintering in the step (3) is an air atmosphere.
Preferably, the method for preparing lithium in step (3) includes mixing the pre-sintered product with a lithium source to obtain a mixture containing the lithium source.
Preferably, the lithium preparation in step (3) further comprises doping.
In the invention, doping during lithium preparation can be adopted, so that the electrical property and stability of the material are further improved.
Preferably, the dopant is selected from at least one of nano zirconia, nano magnesia, nano strontium oxide or nano tungsten oxide, and is preferably nano zirconia.
Preferably, the oxygen concentration in the sintering atmosphere in the step (3) is more than or equal to 80 percent; e.g., 85%, 90%, or 95%, etc.
Preferably, the sintering temperature in step (3) is 600-900 ℃, such as 650 ℃, 700 ℃, 750 ℃, 800 ℃ or 850 ℃, etc.
Preferably, the sintering time in step (3) is 4-15h, such as 5h, 8h, 10h, 12h or 14 h.
As a preferable technical scheme of the invention, the preparation method of the coating modified high-nickel cathode material comprises the following steps:
(1) adding an aluminum nitrate solution into the dispersion liquid of the high-nickel precursor, and stirring to obtain a mixed solution;
(2) adding urea into the mixed solution obtained in the step (1), heating and reacting at 50-85 ℃, filtering, washing and drying to obtain a high-nickel precursor attached with aluminum hydroxide precipitate;
(3) and (3) pre-sintering the high-nickel precursor attached with the aluminum hydroxide precipitate in the step (2) in a muffle furnace at the temperature of 300-600 ℃, mixing the pre-sintered product with a lithium source and a doping agent, sintering the mixture for 4-15h at the temperature of 900 ℃ in an oxygen atmosphere, cooling, crushing and sieving to obtain the coating modified high-nickel anode material.
In a second aspect, the invention provides a coating modified high-nickel cathode material prepared by the preparation method of the first aspect.
Preferably, the chemical general formula of the coating modified high-nickel cathode material is LiNiaCobMncMdO2/Al2O3(ii) a Wherein M is at least one of zirconium, magnesium, strontium and tungsten; 0.6. ltoreq. a < 1, 0. ltoreq. d < 0.05, for example 0.005, 0.01, 0.02, 0.03 or 0.04, etc., a + b + c + d being 1.
Compared with the high-nickel anode material which is obtained by directly matching lithium and sintering without coating the precursor, the coating modified high-nickel anode material has higher structural stability and cycle performance.
Preferably, 0.005 < d < 0.05, such as 0.01, 0.02, 0.03 or 0.04, etc.
In a third aspect, the invention provides a lithium ion battery comprising the coating-modified high-nickel cathode material according to the second aspect.
The lithium ion battery prepared by the coating modified high-nickel cathode material has better cycle performance, thermal stability and safety.
Compared with the prior art, the invention has the following beneficial effects:
(1) in the preparation process of the coating modified high-nickel anode material, urea is used as a precipitator and added into a mixed solution of an aluminum source solution and a dispersion liquid of a high-nickel precursor, the uniform reaction is carried out, aluminum hydroxide is slowly generated and uniformly deposited on the surface of the high-nickel precursor, and the high-nickel anode material with a uniformly coated modified layer is obtained through presintering, lithium preparation and sintering; the aluminum oxide in the coating layer can penetrate into the surface layer of the material and the deep part of the surface to fill the lattice gap of the material, so that the surface is modified, the coating is more compact, and the stability of the material is improved;
(2) the preparation process of the method is simple to operate, safe and low in cost.
Drawings
Fig. 1 is a scanning electron microscope image of the coating modified high nickel cathode material prepared in example 1 of the present invention.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.
Example 1
The chemical formula of the high nickel precursor used in this example is Ni0.83Co0.12Mn0.05(OH)2；
The preparation method of the coating modified high-nickel cathode material comprises the following steps:
(1) adding an aluminum nitrate solution into the dispersion liquid of the high-nickel precursor, and stirring to obtain a mixed solution; wherein the aluminum nitrate solution is added in an amount such that Al is obtained therefrom2O3The mass ratio of the nickel precursor to the high nickel precursor is 0.3 percent;
(2) adding urea into the mixed solution obtained in the step (1), heating and reacting for 4h at 65 ℃, filtering, washing and drying to obtain a high-nickel precursor attached with aluminum hydroxide precipitate; wherein the ratio of the molar amount of urea to the molar amount of aluminum source is 15: 1;
(3) and (3) presintering the high-nickel precursor attached with the aluminum hydroxide precipitate in the step (2) in a muffle furnace at 450 ℃ for 8h, mixing the presintering product with lithium hydroxide and nano zirconia, then sintering for 8h at 800 ℃ in an oxygen atmosphere, cooling, crushing and sieving to obtain the coating modified high-nickel anode material.
The chemical formula of the coating modified high-nickel cathode material obtained in this example is LiNi0.83Co0.1Mn0.05Zr0.02O2/Al2O3；
The scanning electron microscope image of the coating modified high-nickel cathode material obtained in this example is shown in fig. 1, and it can be seen from fig. 1 that alumina is uniformly and tightly coated in the gaps on the surface of the material.
Example 2
This example is different from example 1 in that doping is not performed in step (3), and other parameters and conditions are exactly the same as those in example 1.
Example 3
This example differs from example 1 in that the ratio of the molar amount of urea to the molar amount of aluminium source in step (2) is 12:1, and the other parameters and conditions are exactly the same as in example 1.
Example 4
This example differs from example 1 in that the ratio of the molar amount of urea to the molar amount of aluminium source in step (2) is 18:1, and the other parameters and conditions are exactly the same as in example 1.
Example 5
This example differs from example 1 in that the amount of aluminum nitrate solution added in step (1) is such that Al is obtained therefrom2O3The mass ratio of (2) to the high nickel precursor was 1.2%, and other parameters and conditions were exactly the same as those in example 1.
Example 6
This example differs from example 1 in that the amount of aluminum nitrate solution added in step (1) is such that Al is obtained therefrom2O3Quality and before high nickelThe ratio of the precursors was 0.05% by mass, and other parameters and conditions were exactly the same as those in example 1.
Example 7
This example is different from example 1 in that the dopant was replaced with nano strontium oxide in step (3), and other parameters and conditions were exactly the same as those in example 1.
Example 8
This example differs from example 1 in that the temperature for the pre-sintering in step (1) was replaced with 700 c and the other parameters and conditions were exactly the same as in example 1.
Example 9
This example is different from example 1 in that the temperature for the pre-sintering in step (1) was replaced with 200 ℃ and other parameters and conditions were exactly the same as those in example 1.
Comparative example 1
This comparative example differs from example 2 in that urea was replaced with an equimolar amount of aqueous ammonia in step (2), and other parameters and conditions were exactly the same as those in example 1.
Comparative example 2
The difference between the comparative example and the example 2 is that the high nickel precursor is not coated with alumina, i.e. the high nickel precursor is directly subjected to lithium preparation and sintering to obtain the high nickel cathode material, and other parameters and conditions are completely the same as those in the example 2.
Comparative example 3
In the comparative example, the high nickel cathode material in the comparative example 2 was prepared into a dispersion, and then an aluminum nitrate solution was added, ammonia was added dropwise, and the resulting mixture was filtered, precipitated, dried, and sintered at 700 ℃.
And (3) performance testing:
the coated modified positive electrode materials provided in the examples and comparative examples were used as positive electrode active materials to prepare test cells for performance tests.
The preparation method of the test battery comprises the following steps: adding a certain amount of NMP into a conductive agent and a binder according to a certain proportion, fully stirring in a vacuum stirrer, adding a positive active material (positive active material:adhesive: the conductive agent is 95: 2: 5) uniformly stirring to prepare slurry, coating the slurry on an aluminum foil, drying and rolling to prepare a positive plate, welding a tab of an aluminum strip, laminating the aluminum strip tab with a graphite negative plate and a diaphragm which are prepared in advance, then packaging a core package in a soft package aluminum-plastic film of 396389 model, baking for 8 hours in vacuum, and then using LiPF6Injecting electrolyte solution of/EC + DEC + DMC (the volume ratio of EC, DEC and DMC is 1:1:1), aging at normal temperature for 24h, forming, aging at high temperature, evacuating, sealing, and grading to obtain the battery.
Gram volume: a thermostat at 25 ℃, charging to 4.25V at a constant current and a constant voltage of 0.33 ℃, and discharging to 2.8V at a constant current of 0.33 ℃;
and (3) circulation: charging to 4.25V at constant current and constant voltage of 1C and discharging to 2.8V at constant current of 1C in a constant temperature box at 45 ℃, and circulating for 200 weeks;
differential Scanning Calorimeter (DSC): 033C is charged at constant current and constant voltage to 4.25V, then the anode plate is disassembled, a DSC device is adopted to test the anode plate in an inert atmosphere, the temperature is 25-500 ℃, the heating rate is 5 ℃/min, and the decomposition temperature of the anode plate is compared to represent the structure and the thermal stability of the anode plate.
And (3) high-temperature storage: 033C is charged at constant current and constant voltage to 4.25V, then the battery is placed in a thermostat with the temperature of 70 ℃ for storage for 30 days, and the volume of the battery cell is tested by adopting a drainage method before and after storage so as to represent gas production and structural stability of the material.
The above test results are shown in table 1;
TABLE 1
Figure BDA0002699543850000101
Figure BDA0002699543850000111
As can be seen from table 1 above, in the method of the present invention, urea is used as a precipitant, a mixed solution of an aluminum source and a high nickel precursor is added to uniformly precipitate the aluminum source on the surface of the high nickel precursor, and then the high nickel cathode material with a uniform coating layer is obtained through pre-sintering, lithium preparation, doping and sintering; by adopting the coating method, the stability of the material can be effectively improved, and the coating modified high-nickel cathode material has excellent cycle performance, safety and thermal stability; the scheme of the invention has the advantages of simple operation, safety and low cost.
Comparing example 2 with comparative example 1, it can be seen that urea is replaced by ammonia water, so that the coating of alumina on the surface of the high-nickel precursor material is not uniform, and the performance of the material is further influenced; so that the cycle performance, safety performance and thermal stability thereof are deteriorated.
It can be seen from the comparison between example 2 and comparative example 2 that the cathode material obtained by the preparation method of the present invention has higher stability, and further, the cycle performance, safety and thermal stability of the cathode material are improved.
Comparing example 2 with comparative example 3, it can be seen that the present invention employs first coating the high nickel precursor, and then sintering with lithium, which is more favorable for improving the structural stability of the material.
Comparing example 1 with example 2, it can be seen that the method of the present invention is advantageous to improve the cycle performance, thermal stability and safety of the material by proper doping.
It can be seen from the comparison between example 1 and examples 3 to 4 that the molar amounts of urea and aluminum source were controlled to (14 to 16):1, and the performance of the resultant coating-modified high nickel positive electrode material was the best.
Comparing example 1 with examples 5 to 6, it can be seen that when the mass of the high nickel precursor is 100%, the addition amount of the aluminum source solution is such that the mass percentage content of the aluminum oxide obtained by conversion of the aluminum source solution is 0.1% to 0.8%, the performance of the obtained coating modified high nickel cathode material is optimal;
comparing example 1 and examples 8-9, it can be seen that the pre-sintering temperature is controlled within the range of 300-600 ℃, and the performance of the obtained coating modified high nickel cathode material is the best.
The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.

Claims (10)

1. A preparation method of a coating modified high-nickel cathode material is characterized by comprising the following steps:
(1) mixing an aluminum source solution with a dispersion liquid of a high-nickel precursor to obtain a mixed solution;
(2) adding urea into the mixed solution obtained in the step (1), and heating for reaction;
(3) and (3) presintering the solid product obtained in the step (2), preparing lithium, and sintering to obtain the coating modified high-nickel cathode material.
2. The method of claim 1, wherein the aluminum source in step (1) comprises aluminum nitrate;
preferably, the chemical formula of the high nickel precursor in step (1) is NixCoyMnz(OH)2Wherein x is selected from 0.6-1, and x + y + z is 1.
3. The method according to claim 1 or 2, wherein the aluminum source solution is added in the step (1) in an amount such that the mass percentage of the aluminum oxide converted from the aluminum source solution is 0.1% to 0.8%, preferably 0.3% to 0.5%, based on 100% by mass of the high-nickel precursor.
4. The process according to any one of claims 1 to 3, wherein the ratio of the molar amount of urea added in step (2) to the molar amount of aluminium source in step (1) is (14-16): 1.
5. The production method according to any one of claims 1 to 4, wherein the temperature of the heating reaction in the step (2) is 50 to 85 ℃;
preferably, the heating reaction time in the step (2) is 3-5 h;
preferably, the heating reaction in step (2) is completed by solid-liquid separation, washing and drying.
6. The method according to any one of claims 1 to 5, wherein the temperature for pre-sintering in step (3) is 300-600 ℃;
preferably, the pre-sintering time in the step (3) is 4-15 h;
preferably, the atmosphere of the pre-sintering in the step (3) is an air atmosphere.
7. The method according to any one of claims 1 to 6, wherein the lithium compounding in step (3) comprises mixing the presintered product with a lithium source to obtain a mixture comprising the lithium source;
preferably, the lithium preparation process in the step (3) further comprises doping;
preferably, the dopant is selected from at least one of nano zirconia, nano magnesia, nano strontium oxide or nano tungsten oxide;
preferably, the oxygen concentration in the sintering atmosphere in the step (3) is more than or equal to 80 percent;
preferably, the sintering temperature in the step (3) is 600-900 ℃;
preferably, the sintering time in the step (3) is 4-15 h.
8. The method of any one of claims 1 to 7, comprising the steps of:
(1) adding an aluminum nitrate solution into the dispersion liquid of the high-nickel precursor, and stirring to obtain a mixed solution;
(2) adding urea into the mixed solution obtained in the step (1), heating and reacting at 50-85 ℃, filtering, washing and drying to obtain a high-nickel precursor attached with aluminum hydroxide precipitate;
(3) and (3) pre-sintering the high-nickel precursor attached with the aluminum hydroxide precipitate in the step (2) in a muffle furnace at the temperature of 300-600 ℃, mixing the pre-sintered product with a lithium source and a doping agent, sintering the mixture for 4-15h at the temperature of 900 ℃ in an oxygen atmosphere, cooling, crushing and sieving to obtain the coating modified high-nickel anode material.
9. The coating-modified high-nickel cathode material prepared by the preparation method according to any one of claims 1 to 8.
10. A lithium ion battery comprising the coating-modified high-nickel positive electrode material according to claim 9.
CN202011017484.2A 2020-09-24 2020-09-24 Coating modified high-nickel cathode material and preparation method and application thereof Pending CN112186155A (en)

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CN103606660A (en) * 2013-11-06 2014-02-26 中国科学院化学研究所 Alumina-coated granules, as well as preparation method and application thereof
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CN103178258A (en) * 2013-01-21 2013-06-26 宁德新能源科技有限公司 Method for preparing aluminum oxide coated modified lithium nickel cobalt manganese oxygen cathode material
CN103606660A (en) * 2013-11-06 2014-02-26 中国科学院化学研究所 Alumina-coated granules, as well as preparation method and application thereof
CN111244397A (en) * 2018-11-28 2020-06-05 天津国安盟固利新材料科技股份有限公司 High-nickel ternary cathode material and preparation method thereof

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