CN115784321B - Modified nickel cobalt lithium manganate positive electrode material and preparation method thereof - Google Patents

Modified nickel cobalt lithium manganate positive electrode material and preparation method thereof Download PDF

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CN115784321B
CN115784321B CN202211472079.9A CN202211472079A CN115784321B CN 115784321 B CN115784321 B CN 115784321B CN 202211472079 A CN202211472079 A CN 202211472079A CN 115784321 B CN115784321 B CN 115784321B
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modified
nickel cobalt
lithium manganate
chitosan
cobalt lithium
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CN115784321A (en
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谢英豪
李爱霞
余海军
张学梅
李长东
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Hunan Brunp Recycling Technology Co Ltd
Guangdong Brunp Recycling Technology Co Ltd
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Hunan Brunp Recycling Technology Co Ltd
Guangdong Brunp Recycling Technology Co Ltd
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    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries

Abstract

The invention discloses a modified nickel cobalt lithium manganate positive electrode material and a preparation method thereof, and belongs to the technical field of positive electrode materials. The preparation method comprises the following steps: mixing the modified mixed solution with a nickel cobalt lithium manganate matrix to be coated for reaction, and freeze-drying; the modified mixed solution is prepared by mixing modified chitosan coating solution and conductive particles modified by a silane coupling agent; the modified chitosan coating liquid is obtained by mixing modified chitosan obtained by modifying chitosan by an imidazole compound with carboxyl with a solvent, and the silane coupling agent is silane with ethoxy. The method can effectively improve the binding force between the modified chitosan and the matrix; in the freeze drying process, the solvent in the modified chitosan coating liquid forms an ice crystal structure firstly, and then is sublimated and volatilized directly to remove the ice crystal structure, so that a pore structure of the nickel cobalt lithium manganate matrix is improved, migration and diffusion of lithium ions are facilitated, and the multiplying power and the cycle performance of the corresponding material can be improved.

Description

Modified nickel cobalt lithium manganate positive electrode material and preparation method thereof
Technical Field
The invention relates to the technical field of positive electrode materials, in particular to a modified nickel cobalt lithium manganate positive electrode material and a preparation method thereof.
Background
The nickel cobalt lithium manganate anode material currently faces the problems of rapid cycle capacity decay, pulverization of agglomerated particles, poor structural stability and the like under the high voltage condition, and in order to alleviate the problems, a mode of coating metal oxide, fluoride, phosphate, silicate and carbon materials is generally adopted in the prior art.
The existing coating mode can alleviate the problem of pulverization of agglomerated particles and poor structural stability under the high-voltage condition to a certain extent, but the material circulation retention rate is still to be further improved.
In view of this, the present invention has been made.
Disclosure of Invention
The invention aims to provide a preparation method of a modified nickel cobalt lithium manganate positive electrode material to solve the technical problems.
The second purpose of the invention is to provide a modified coated nickel cobalt lithium manganate anode material prepared by the preparation method.
The application can be realized as follows:
in a first aspect, the present application provides a method for preparing a modified lithium nickel cobalt manganese oxide positive electrode material, including the following steps: mixing the modified mixed solution with a nickel cobalt lithium manganate matrix to be coated for reaction to form a modified chitosan film on the surface of the nickel cobalt lithium manganate matrix, and then freeze-drying to form a porous structure of the modified chitosan film;
the modified mixed solution is prepared by mixing modified chitosan coating solution and conductive particles modified by a silane coupling agent; the modified chitosan coating liquid is obtained by mixing modified chitosan with a solvent; the modified chitosan is obtained by modifying chitosan by imidazole compound with carboxyl; the silane coupling agent is silane with ethoxy.
In an alternative embodiment, the modified mixture is sprayed onto the surface of the lithium nickel cobalt manganese oxide substrate to be coated, followed by freeze-drying.
In an alternative embodiment, the mass ratio of the modified chitosan coating liquid, the silane coupling agent modified conductive particles and the nickel cobalt lithium manganate matrix is 80-100:3-5:100.
In an alternative embodiment, 30-50g of modified chitosan is contained per liter of modified chitosan coating solution.
In an alternative embodiment, the solvent is an aqueous acetic acid solution.
In an alternative embodiment, the concentration of acetic acid in the aqueous acetic acid solution is 0.5-1.5% by volume.
In an alternative embodiment, the modified chitosan is obtained by acylating an imidazole compound having a carboxyl group with chitosan.
In an alternative embodiment, the imidazole compound having a carboxyl group includes at least one of imidazole-4-acetic acid and imidazole-1-carboxylic acid.
In an alternative embodiment, the molar ratio of imidazole compound having a carboxyl group to chitosan is 1-3:2-5.
In an alternative embodiment, the chitosan has a mesh number of 40-80 mesh and a degree of deacetylation of 85-95%.
In an alternative embodiment, the silane coupling agent is an epoxy silane having an ethoxy group.
In an alternative embodiment, the silane coupling agent is a cycloaliphatic epoxy silane having an ethoxy group.
In an alternative embodiment, the epoxysilane is triethoxy [2- (7-oxabicyclo [4.1.0] hept-3-yl) ethyl ] silane.
In an alternative embodiment, the conductive particles include at least one of zinc oxide and carbon nanotubes.
In an alternative embodiment, the nickel cobalt lithium manganate matrix is sintered from a nickel cobalt manganese precursor mixed with a lithium source.
In an alternative embodiment, the nickel cobalt manganese precursor is a nickel cobalt manganese hydroxide.
In an alternative embodiment, the lithium source comprises lithium carbonate.
In an alternative embodiment, the preparation of the nickel cobalt lithium manganate matrix further comprises: and crushing the sintered material to obtain nickel cobalt lithium manganate powder.
In an alternative embodiment, the nickel cobalt lithium manganate powder has a median particle size of 10 to 20 μm.
In an alternative embodiment, the freeze drying is vacuum drying in a refrigerated environment.
In an alternative embodiment, the method further comprises: washing the nickel cobalt lithium manganate matrix coated with the porous modified chitosan film to remove residual solvent, then carrying out solid-liquid separation, and drying the solid phase.
In a second aspect, the present application provides a modified lithium nickel cobalt manganese oxide positive electrode material, which is prepared by the preparation method according to any one of the foregoing embodiments.
The beneficial effects of this application include:
according to the preparation method, the carboxyl on the imidazole compound reacts with the active amino of the chitosan to form chemical bonding, so that the modified chitosan solution with an imidazole structure is obtained, and the dissolution of transition metal of the positive electrode material in the circulation process can be effectively inhibited.
By using the silane coupling agent group with ethoxy, on one hand, the silane coupling agent group can form intermolecular force with unreacted hydroxyl and amino groups on chitosan (namely, even if the silane coupling agent group has good bonding force between all positions of the membrane), and on the other hand, the silane coupling agent group with ethoxy also has good bonding force with a matrix, so that the bonding force between the modified chitosan and the nickel cobalt lithium manganate matrix and the bonding force between the internal structures of the membrane are improved.
The porous modified chitosan film contains conductive particles, so that the conductivity of the positive electrode material can be improved.
After freeze drying, the modified chitosan film forms a porous structure, which is favorable for migration and diffusion of lithium ions, and further can improve the multiplying power and the cycle performance of the corresponding material.
The prepared modified nickel cobalt lithium manganate positive electrode material has good cycle retention rate and rate capability.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is an SEM image of a modified lithium nickel cobalt manganese oxide positive electrode material prepared in example 1 of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
The modified nickel cobalt lithium manganate positive electrode material and the preparation method thereof provided by the application are specifically described below.
The application provides a preparation method of a modified nickel cobalt lithium manganate positive electrode material, which comprises the following steps: and mixing the modified mixed solution with a nickel cobalt lithium manganate matrix to be coated for reaction to form a modified chitosan film on the surface of the nickel cobalt lithium manganate matrix, and then freeze-drying to form a porous structure of the modified chitosan film.
The modified mixed solution is prepared by mixing modified chitosan coating solution and conductive particles modified by a silane coupling agent; the modified chitosan coating liquid is obtained by mixing modified chitosan with a solvent; the modified chitosan is obtained by modifying chitosan by imidazole compound with carboxyl; the silane coupling agent is silane with ethoxy.
The modified chitosan is obtained by the acylation reaction of an imidazole compound with carboxyl and chitosan. Specifically, the carboxyl on the imidazole compound reacts with the active amino of chitosan to form chemical bonding, so that the modified chitosan solution with the imidazole structure is obtained. The modified chitosan solution can effectively inhibit the dissolution of transition metal of the anode material in the circulation process.
Preferably, the imidazole compound having a carboxyl group used in the present application preferably includes at least one of imidazole-4-acetic acid and imidazole-1-carboxylic acid. Compared with other imidazole compounds with carboxyl, the two compounds can obtain the positive electrode material with higher cycle retention rate under the preparation conditions of the application.
In the preparation process, the molar ratio of the imidazole compound with carboxyl to chitosan is 1-3:2-5, for example, 1:2, 1:3, 1:4, 1:5, 2:2, 2:3, 2:4, 2:5, 3:2, 3:4 or 3:5, and the like, and any other value in the range of 1-3:2-5 can be used.
The chitosan used may be 40-80 mesh in number and 85-95% deacetylated to ensure high solubility.
In the application, 30-50g (such as 30g, 35g, 40g, 45g or 50 g) of modified chitosan is contained in each liter of modified chitosan coating liquid.
The solvent used in the modified chitosan coating liquid is acetic acid aqueous solution, and the volume concentration of acetic acid in the acetic acid aqueous solution is 0.5-1.5%, so that the modified chitosan with an imidazole structure can be fully dissolved.
The silane coupling agent used in the application has ethoxy, on one hand, the silane coupling agent can form intermolecular acting force with unreacted hydroxyl and amino on chitosan (namely, even if the silane coupling agent has good bonding force between all positions of the membrane), and on the other hand, the silane coupling agent also has good bonding force with a matrix, so that the bonding force between the modified chitosan and the nickel cobalt lithium manganate matrix and the bonding force between the internal structures of the membrane are improved. The porous modified chitosan film contains conductive particles, so that the conductivity of the positive electrode material can be improved.
Preferably, the silane coupling agent is epoxy silane having ethoxy group. More preferably, the silane coupling agent is an alicyclic epoxy silane having an ethoxy group.
In some specific embodiments, the epoxysilane is triethoxy [2- (7-oxabicyclo [4.1.0] hept-3-yl) ethyl ] silane. The molecular structure of the material contains three hydrolytic alkoxy (ethoxy) groups, and the dual reactivity can improve the combination and compatibility degree between the nickel cobalt lithium manganate matrix and the modified chitosan through the bidirectional chemical reaction between the nickel cobalt lithium manganate matrix and the modified chitosan.
In other embodiments, it is not excluded that other cycloaliphatic epoxy silane materials having ethoxy groups may be employed.
As an example, the conductive particles may include at least one of zinc oxide and carbon nanotubes. Further, it may be conductive graphite, conductive carbon black, graphene, carbon fiber, or the like.
By using the conductive particles, the conductivity of the positive electrode material can be improved.
The preparation method of the conductive particles modified by the silane coupling agent comprises the steps of adding the conductive particles into an organic solvent (such as toluene) to obtain a suspension by ultrasonic dispersion, then adding the silane coupling agent to perform ultrasonic dispersion, reacting for 3-6 hours at the constant temperature of 80-90 ℃, and performing centrifugal separation at the normal temperature to obtain the conductive particles modified by the silane coupling agent.
Wherein, the mass ratio of the silane coupling agent to the conductive particles can be 3-5:8-10, the dosage of the organic solvent and the conductive particles is 20-30mL:0.8-1g.
In the present application, the mass ratio of the modified chitosan coating solution, the silane coupling agent modified conductive particles, and the nickel cobalt lithium manganate matrix may be 80-100:3-5:100, such as 80:3:100, 80:3.5:100, 80:4:100, 80:4.5:100, 80:5:100, 85:3:100, 85:3.5:100, 85:4:100, 85:4.5:100, 85:5:100, 90:3:100, 90:3.5:100, 90:4:100, 90:4.5:100, 90:5:100, 95:3:100, 95:3.5:100, 95:4:100, 95:4.5:100, 95:5:100, 100:3:100, 100:3.5:100, 100:4:100, 100:4.5:100, or 100:5:100, etc., and may also be any other value within the range of 80-100:3-5:100.
If the amount of the modified chitosan coating liquid or the conductive particles modified with the silane coupling agent is too small, the binding force between the substrate and the modified chitosan film may be poor. If the dosage of the modified chitosan coating liquid is too large, or the dosage of the conductive particles modified by the silane coupling agent is too large, the excessive attachments on the surface of the nickel cobalt lithium manganate matrix easily influence the performance of the matrix, such as the lithium ion deintercalation capability, to be reduced.
As an example, the above-mentioned nickel cobalt lithium manganate matrix may be formed by mixing and sintering a nickel cobalt manganese precursor and a lithium source.
The nickel cobalt manganese precursor can be nickel cobalt manganese hydroxide, and the lithium source can be lithium carbonate or lithium hydroxide.
Further, the preparation of the nickel cobalt lithium manganate matrix further comprises: and crushing the sintered material to obtain nickel cobalt lithium manganate powder.
Preferably, the median particle diameter of the crushed nickel cobalt lithium manganate powder is 10-20 mu m.
By taking the nickel cobalt lithium manganate powder with the particle size as a matrix, particle agglomeration can be avoided, and the modified mixed solution can be uniformly and effectively coated.
It should be noted that, the nickel cobalt lithium manganate matrix used in the present application is a common nickel cobalt lithium manganate precursor in the field, and the chemical formula, the preparation process and the preparation conditions of the nickel cobalt lithium manganate precursor are not excessively limited in the present application, and specific reference may be made to related prior art.
In the application, the coating of the modified mixed solution on the nickel cobalt lithium manganate matrix can be as follows: spraying the modified mixed solution on the surfaces of the nickel cobalt lithium manganate matrixes to be coated, and then mixing the matrixes sprayed with the modified mixed solution.
In the above process, the usage amount relationship between the modified mixed solution and the nickel cobalt lithium manganate matrix may be 83-105:100, such as 83:100, 85:100, 90:100, 95:100, 100:100, 102:100 or 105:100, and the like, and may also be any other value within the range of 83-105:100.
The mixing of the above substrates may be carried out at 50-60 ℃.
It should be noted that the above mixing process is performed at 50-60 ℃, so that the adhesion reaction rate of the modified mixed solution and the nickel cobalt lithium manganate matrix can be accelerated, and the binding force of the coating is tighter.
In this application, the freeze-drying is vacuum-drying under a freezing environment, and specific reference may be made to the related art, and redundant description is omitted herein.
In the freeze drying process, the solvent in the modified chitosan coating liquid is frozen into a solid state at a lower temperature, and then the moisture in the modified chitosan coating liquid is sublimated into a gas state directly without being in a liquid state under vacuum, so that the material is dehydrated and dried. After sublimation, the positions corresponding to the moisture in the original solid state form a hole structure, and meanwhile, the process can remove the moisture possibly existing on the surface or in the precursor, so that the pore structure of the nickel cobalt lithium manganate matrix is improved, the migration and diffusion of lithium ions are facilitated, and the multiplying power and the cycle performance of the corresponding material can be improved.
Further, after freeze-drying, the nickel cobalt lithium manganate matrix coated with the porous modified chitosan film on the surface is washed to remove residual solvent, then solid-liquid separation is carried out, and the solid phase is dried.
Correspondingly, the application also provides a modified nickel cobalt lithium manganate positive electrode material which is prepared by the preparation method.
The modified nickel cobalt lithium manganate positive electrode material can relieve volume strain in the circulation process, inhibit surface side reaction, improve electronic conductivity, and has higher coulomb efficiency, circulation stability and rate capability.
The features and capabilities of the present invention are described in further detail below in connection with the examples.
Example 1
The embodiment provides a modified nickel cobalt lithium manganate positive electrode material, which is prepared by the following steps:
step (1): the modified mixed solution was sprayed onto a nickel cobalt lithium manganate matrix (LiNi) at a ratio of 105g to 100g 0.9 Co 0.05 Mn 0.05 O 2 A median particle diameter of 15 μm).
The modified mixture is obtained by mixing the modified chitosan coating liquid and the conductive particles modified by the silane coupling agent.
The modified chitosan coating liquid is obtained by mixing modified chitosan and 1vt percent acetic acid aqueous solution according to the proportion of 30g to 1L, wherein the modified chitosan is obtained by carrying out acylation reaction on imidazole-4-acetic acid and chitosan according to the mol ratio of 2 to 3, the mesh number of the chitosan is 60, and the deacetylation degree of the chitosan is 90%.
The silane coupling agent modified conductive particles are prepared by the following method: adding zinc oxide into toluene, performing ultrasonic dispersion to obtain suspension, adding triethoxy [2- (7-oxabicyclo [4.1.0] hept-3-yl) ethyl ] silane, performing ultrasonic dispersion, reacting at a constant temperature of 85 ℃ for 5 hours, and performing centrifugal separation at normal temperature to obtain silane coupling agent modified conductive particles. Wherein, the mass ratio of the triethoxy [2- (7-oxabicyclo [4.1.0] hept-3-yl) ethyl ] silane to the zinc oxide is 3: and 8, the dosage of toluene and zinc oxide is 25mL:1g.
The mass ratio of the modified chitosan coating liquid to the silane coupling agent modified conductive particles to the nickel cobalt lithium manganate matrix is 100:5:100.
Step (2): and mixing and reacting the nickel cobalt lithium manganate matrixes attached with the modified mixed solution at the temperature of 60 ℃ to form a modified chitosan film on the surfaces of the nickel cobalt lithium manganate matrixes, and then cooling to room temperature.
Step (3): and (3) freeze-drying the material obtained in the step (2) to form a porous structure of the modified chitosan film.
Step (4): and washing the dried product with water to remove residual acetic acid, and drying the water to obtain the modified nickel cobalt lithium manganate anode material.
Example 2
This embodiment differs from embodiment 1 in that: imidazole-1-carboxylic acid was used instead of imidazole-4-acetic acid.
Example 3
This embodiment differs from embodiment 1 in that: each liter of modified chitosan coating liquid contains 40g of modified chitosan.
Example 4
This embodiment differs from embodiment 1 in that: each liter of modified chitosan coating liquid contains 50g of modified chitosan.
Example 5
This embodiment differs from embodiment 1 in that: the mass ratio of the modified chitosan coating liquid to the silane coupling agent modified conductive particles to the nickel cobalt lithium manganate matrix is 80:3:100.
Example 6
This embodiment differs from embodiment 1 in that: the mass ratio of the modified chitosan coating liquid to the silane coupling agent modified conductive particles to the nickel cobalt lithium manganate matrix is 90:4:100.
Example 7
This embodiment differs from embodiment 1 in that: the molar ratio of imidazole-4-acetic acid to chitosan is 1:2.
Example 8
This embodiment differs from embodiment 1 in that: the molar ratio of imidazole-4-acetic acid to chitosan was 3:5.
Comparative example 1
The difference between this comparative example and example 1 is that: the modified mixture is obtained by mixing chitosan coating liquid and conductive particles modified by a silane coupling agent. Wherein the chitosan coating liquid is prepared by dissolving unmodified chitosan in acetic acid aqueous solution.
That is, in this comparative example, chitosan was not modified with an imidazole compound having a carboxyl group.
Comparative example 2
The difference between this comparative example and example 1 is that: the modified mixed solution does not contain modified chitosan and only contains conductive particles modified by a silane coupling agent.
Comparative example 3
The difference between this comparative example and example 1 is that: the modified mixed solution is obtained by mixing the modified chitosan coating solution and the conductive particles, and does not contain a silane coupling agent.
That is, the conductive particles in this comparative example were not modified with the silane coupling agent.
Comparative example 4
The difference between this comparative example and example 1 is that: the modified mixed solution is prepared by mixing a modified chitosan coating solution and a silane coupling agent, and does not contain conductive particles.
Comparative example 5
The difference between this comparative example and example 1 is that:
the imidazole compound is as follows:
wherein Y is BF 4 -
Comparative example 6
The difference between this comparative example and example 1 is that: the imidazole compound having a carboxyl group is imidazole-4, 5-dicarboxylic acid.
Comparative example 7
The difference between this comparative example and example 1 is that: the silane coupling agent is gamma-methacryloxypropyl trimethoxy.
Comparative example 8
The difference between this comparative example and example 1 is that: the silane coupling agent is 2- (3, 4-epoxycyclohexane) ethyl trimethoxy silane with a molecular formula of C 11 H 22 O 4 Si。
Comparative example 9
The difference between this comparative example and example 1 is that: silane coupling agent ethoxy trimethyl silane with molecular formula of C 5 H 14 OSi。
Test examples
(1) Taking the positive electrode material prepared in example 1 as an example, electron microscope scanning is performed on the positive electrode material, and an SEM (scanning electron microscope) diagram of the positive electrode material is shown in FIG. 1.
(2) The positive electrode materials obtained in examples 1 to 8 and comparative examples 1 to 9 were each prepared into a button cell in the following manner for testing electrochemical properties of lithium ion batteries:
n-methyl pyrrolidone is used as a solvent, the anode active material, acetylene black and PVDF are uniformly mixed according to the mass ratio of 9.2:0.5:0.3, the mixture is coated on an aluminum foil, and the mixture is dried for 8 hours by blowing at 80 ℃ and then is dried for 12 hours in vacuum at 120 ℃. The battery was assembled in an argon-protected glove box, the negative electrode was a metallic lithium sheet, the separator was a polypropylene film, the electrolyte was 1m LiPF6-EC/DMC (1:1, V/V), a 2032-type button cell case was used to assemble the button cell in an argon-protected glove box, and then electrochemical performance tests were performed at 25 ℃ at 3.0-4.5V, the results of which are shown in table 1 below.
Table 1 test results
As can be seen from table 1: the modified nickel cobalt lithium manganate positive electrode material prepared by the preparation method provided by the application has good cycle retention rate.
In conclusion, the scheme provided by the application can effectively improve the binding force between the modified chitosan and the matrix; in the freeze drying process, the solvent in the modified chitosan coating liquid forms an ice crystal structure firstly, and then is sublimated and volatilized directly to remove the ice crystal structure, so that a pore structure of the nickel cobalt lithium manganate matrix is improved, migration and diffusion of lithium ions are facilitated, and the multiplying power and the cycle performance of the corresponding material can be improved.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (12)

1. The preparation method of the modified nickel cobalt lithium manganate positive electrode material is characterized by comprising the following steps of: mixing the modified mixed solution with a nickel cobalt lithium manganate matrix to be coated for reaction to form a modified chitosan film on the surface of the nickel cobalt lithium manganate matrix, and then freeze-drying to enable the modified chitosan film to form a porous structure;
the modified mixed solution is prepared by mixing modified chitosan coating solution and conductive particles modified by a silane coupling agent; the modified chitosan coating liquid is obtained by mixing modified chitosan with a solvent;
spraying the modified mixed solution on the surface of the nickel cobalt lithium manganate matrix to be coated, and then freeze-drying; the mass ratio of the modified chitosan coating liquid to the silane coupling agent modified conductive particles to the nickel cobalt lithium manganate matrix is 80-100:3-5:100;
each liter of the modified chitosan coating liquid contains 30-50g of the modified chitosan;
the modified chitosan is obtained by carrying out acylation reaction on an imidazole compound with carboxyl and chitosan; the imidazole compound with carboxyl is at least one of imidazole-4-acetic acid and imidazole-1-carboxylic acid; the molar ratio of the imidazole compound with carboxyl to the chitosan is 1-3:2-5; the deacetylation degree of the chitosan is 85-95%;
the silane coupling agent is triethoxy [2- (7-oxabicyclo [4.1.0] hept-3-yl) ethyl ] silane;
the conductive particles include at least one of zinc oxide and carbon nanotubes.
2. The method according to claim 1, wherein the solvent is an aqueous acetic acid solution.
3. The method according to claim 2, wherein the volume concentration of acetic acid in the aqueous acetic acid solution is 0.5 to 1.5%.
4. The method according to claim 1, wherein the chitosan has a mesh number of 40 to 80 mesh.
5. The method of claim 1, wherein the nickel cobalt lithium manganate matrix is sintered from a nickel cobalt manganese precursor and a lithium source.
6. The method of claim 5, wherein the nickel cobalt manganese precursor is nickel cobalt manganese hydroxide.
7. The method of claim 6, wherein the lithium source comprises lithium carbonate.
8. The method of preparing as claimed in claim 5, wherein the preparing of the lithium nickel cobalt manganese oxide matrix further comprises: and crushing the sintered material to obtain nickel cobalt lithium manganate powder.
9. The method according to claim 8, wherein the nickel cobalt lithium manganate powder has a median particle diameter of 10 to 20 μm.
10. The method according to claim 1, wherein the freeze-drying is vacuum-drying in a frozen environment.
11. The method of manufacturing according to claim 1, further comprising: washing the nickel cobalt lithium manganate matrix coated with the porous modified chitosan film to remove residual solvent, then carrying out solid-liquid separation, and drying the solid phase.
12. A modified lithium nickel cobalt manganese oxide positive electrode material, characterized in that it is prepared by the preparation method according to any one of claims 1 to 11.
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