CN113140715B - Composite cathode material, preparation method thereof and lithium ion battery - Google Patents

Composite cathode material, preparation method thereof and lithium ion battery Download PDF

Info

Publication number
CN113140715B
CN113140715B CN202110390281.6A CN202110390281A CN113140715B CN 113140715 B CN113140715 B CN 113140715B CN 202110390281 A CN202110390281 A CN 202110390281A CN 113140715 B CN113140715 B CN 113140715B
Authority
CN
China
Prior art keywords
protective layer
positive electrode
electrode material
cathode material
ternary
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202110390281.6A
Other languages
Chinese (zh)
Other versions
CN113140715A (en
Inventor
黄仁忠
高琦
吴浩
郑江峰
张晨
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Guangdong Jiana Energy Technology Co Ltd
Qingyuan Jiazhi New Materials Research Institute Co Ltd
Original Assignee
Guangdong Jiana Energy Technology Co Ltd
Qingyuan Jiazhi New Materials Research Institute Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Guangdong Jiana Energy Technology Co Ltd, Qingyuan Jiazhi New Materials Research Institute Co Ltd filed Critical Guangdong Jiana Energy Technology Co Ltd
Priority to CN202110390281.6A priority Critical patent/CN113140715B/en
Publication of CN113140715A publication Critical patent/CN113140715A/en
Application granted granted Critical
Publication of CN113140715B publication Critical patent/CN113140715B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • 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
    • 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
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • 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

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Engineering & Computer Science (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)

Abstract

The application relates to the field of lithium batteries, and relates to a composite cathode material, a preparation method thereof and a lithium ion battery. The material comprises an inner core, a first protective layer and a second protective layer. The composition of the first protective layer includes silicon dioxide. The composition of the second protective layer includes a conductive polymer. Through the arrangement of the first protective layer comprising silicon dioxide, an inert protection effect is formed on the ternary cathode material kernel, and the side reaction of the ternary cathode material kernel and electrolyte is effectively inhibited, so that the electrode circulation stability is improved. By arranging the second protective layer comprising the conductive polymer, the electrochemical performance of the ternary cathode material core is improved. Through making first protective layer connect in ternary cathode material, second protective layer connect in first protective layer, greatly improved the joint strength between the whole compound cathode material three-layer, guaranteed the stability of whole compound cathode material structure to can guarantee lithium ion battery's circulation stability.

Description

Composite cathode material, preparation method thereof and lithium ion battery
Technical Field
The application relates to the field of lithium batteries, in particular to a composite cathode material, a preparation method thereof and a lithium ion battery.
Background
Lithium ion batteries have many excellent properties, such as long cycle life, large energy density, high operating voltage, and the like.
The positive electrode material has influence on the energy density, specific capacity, stability and other performances of the lithium ion battery.
The ternary cathode material has the characteristic of high energy density. However, the common ternary cathode material at present has the defect that the common ternary cathode material is easy to generate side reaction with electrolyte and influence the cycling stability of the electrode. Other technologies modify the ternary cathode material by adopting carbon coating, but the carbon shell is easily damaged by a core-shell structure obtained by the coating.
Disclosure of Invention
An embodiment of the application aims to provide a composite cathode material, a preparation method thereof and a lithium ion battery, and aims to effectively inhibit side reactions between a ternary core and an electrolyte.
In a first aspect, the present application provides a composite positive electrode material comprising:
the core is a ternary positive electrode material;
the first protective layer is connected to the surface of the inner core; the first protective layer comprises silicon dioxide; and
and the second protective layer is connected to the surface of the first protective layer, and the composition of the second protective layer comprises a conductive polymer.
The composite anode material forms an inert protection effect on the ternary anode material kernel by arranging the first protection layer comprising silicon dioxide, and effectively inhibits the side reaction of the ternary anode material kernel and electrolyte, so that the electrode cycling stability is improved. By arranging the second protective layer comprising the conductive polymer, the electrochemical performance of the ternary cathode material core is improved. Further, the first protection layer is connected to the ternary anode material, and the second protection layer is connected to the first protection layer, so that the connection strength between three layers of the whole composite anode material is greatly improved, the stability of the structure of the whole composite anode material is ensured, and the circulation stability of the lithium ion battery can be ensured. Compared with a carbon-coated core-shell structure in the prior art, the connection strength of the inner core and the outer layer is greatly improved, and the problem that the core-shell structure is easily damaged is solved.
In other embodiments of the present application, the first protective layer is attached to the ternary positive electrode material by a first covalent bond;
optionally, the first covalent bond comprises a siloxane bond.
In other embodiments of the present application, the second protective layer is linked to the first protective layer by a second covalent bond.
In other embodiments of the present application, the conductive polymer is polyaniline. Optionally, the second covalent bond comprises a nitrogen carbon bond.
In other embodiments of the present application, the ternary cathode material is a nickel-cobalt-manganese ternary cathode material with a chemical formula of Li (Ni) 1-x-y Co x Mn y )O 2 Wherein 0 is<x<1，0<y<1。
Optionally, the particle size of the ternary cathode material is 3 μm to 20 μm.
In a second aspect, the present application provides a method for preparing a composite positive electrode material, comprising:
reacting the ternary positive electrode material with a silane coupling agent, and hydrolyzing the silane coupling agent to generate a first protective layer connected to the surface of the ternary positive electrode material, wherein the first protective layer comprises silicon dioxide;
then carrying out in-situ polymerization reaction with polymer monomers to generate a second protective layer connected to the surface of the first protective layer, wherein the components of the second protective layer comprise conductive polymers.
According to the method, the silicon dioxide intermediate layer generated by the hydrolysis reaction of the silane coupling agent can effectively inhibit the side reaction of the ternary core and the electrolyte, so that the circulation stability of the electrode is improved. And the connection of the silicon dioxide and the ternary cathode material is covalent bond connection, so that the connection strength of the connection core and the first protective layer is greatly improved. And then in-situ polymerization is carried out on the surface of the ternary cathode material, so that the second protective layer is connected to the surface of the first protective layer, the connection strength between three layers of the whole composite material is greatly improved, the stability of the structure of the whole composite cathode material is ensured, and the circulation stability of the lithium ion battery can be ensured. Furthermore, the method does not need high-temperature carbonization, greatly reduces the process steps, reduces the preparation difficulty and saves the cost.
In other embodiments of the present application, the step of reacting the ternary cathode material with a silane coupling agent includes:
modifying the ternary cathode material by adopting an alkaline substance to graft hydroxyl on the surface of the ternary cathode material;
then reacting with silane coupling agent to hydrolyze the silane coupling agent to generate silicon dioxide, and grafting aminopropyl on the silicon dioxide.
In other embodiments of the present application, the silane coupling agent is selected from one or more of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyldimethylethoxysilane;
alternatively, the ratio of the amount of silane coupling agent to the amount of material of the ternary positive electrode material is (1-10): 10;
alternatively, the alkaline substance is selected from ammonia water; optionally, the mass fraction of the ammonia water is 25% -28%.
In other embodiments herein, the step of then performing an in situ polymerization reaction with the polymer monomer comprises:
carrying out in-situ polymerization reaction on the positive electrode material connected with the first protective layer, a polymer monomer and an oxidant;
alternatively, the mass concentration of the polymeric monomer is from 0.01mol/L to 0.05 mol/L;
alternatively, the polymer monomer is selected from aniline;
alternatively, the oxidant is selected from ammonium persulfate; alternatively, the mass concentration of the oxidizing agent is 0.02mol/L to 0.1 mol/L.
In a third aspect, the present application provides a lithium ion battery comprising the composite positive electrode material of any one of the preceding; or the lithium ion battery comprises the composite cathode material prepared by the preparation method of the composite cathode material.
The lithium ion battery has excellent cycle stability and conductivity.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.
FIG. 1 is a schematic diagram of a first protective layer generation process;
FIG. 2 is a surface SEM topography of a composite cathode material provided in example 1 of the present application;
fig. 3 shows the cycle performance test results of the composite positive electrode materials provided in examples 1 to 3 and comparative example 1 of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments.
The embodiment of the application provides a preparation method of a composite cathode material, which comprises the following steps:
and step S1, reacting the ternary cathode material with a silane coupling agent to hydrolyze the silane coupling agent to generate a first protective layer connected to the surface of the ternary cathode material, wherein the material of the first protective layer comprises silicon dioxide.
The silane coupling agent can be hydrolyzed to generate silicon dioxide connected to the surface of the ternary cathode material, and the silicon dioxide can effectively inhibit the side reaction of the ternary core and the electrolyte, so that the cycling stability of the electrode is improved.
Therefore, according to the scheme, the first protective layer containing silicon dioxide is connected to the surface of the ternary cathode material, so that the cycle stability of the lithium ion battery can be effectively improved.
It should be noted that the first protective layer obtained by the above method may contain silicon oxide, but since silicon oxide is very unstable in air, silicon oxide is easily oxidized to silicon dioxide in air. Therefore, the main component in the first protective layer is silicon dioxide, so that the effects of inhibiting the side reaction of the ternary core and the electrolyte and improving the cycle stability of the lithium ion battery can be effectively achieved.
It should be noted that, the silane coupling agent is hydrolyzed to generate silica, which is covalently bonded with the ternary cathode material, and thus only a thin layer of silica is formed on the surface of the ternary cathode material. The wrapping method conventional in the art forms a wrapping layer (wrapping other materials on the surface of the ternary cathode material), and multiple layers of materials are inevitably stacked, so that the thickness of the wrapping layer is very thick. Therefore, the first protective layer can be used as a thin inert layer to effectively inhibit the side reaction of the ternary core and the electrolyte, and meanwhile, the thin layer (relative to the conventional wrapping layer) connected by the covalent bond hardly influences the electrochemical performance of the ternary cathode material.
Further, the step of reacting the ternary cathode material with a silane coupling agent comprises:
modifying the ternary cathode material by adopting an alkaline substance to graft hydroxyl on the surface of the ternary cathode material;
then reacting with silane coupling agent to hydrolyze the silane coupling agent to generate silicon dioxide, and grafting aminopropyl on the silicon dioxide.
By grafting hydroxyl on the surface of the ternary cathode material, the ternary cathode material can be connected with a silane-coupled hydrolysate in a covalent bond manner, so that the connection strength of the first protective layer and the ternary cathode material can be effectively improved.
Furthermore, the aminopropyl is grafted on the silicon dioxide and can be used as a reaction site of subsequent polymerization reaction, so that the second protective layer and the first protective layer form covalent bond connection, and the connection strength of the first protective layer and the second protective layer is improved.
Further, the ternary cathode material is mixed with alkali, and then a silane coupling agent is added for reaction.
Further, ammonia is selected as the base.
Further optionally, the mass fraction of the ammonia water is 25% to 28%. Illustratively, the mass fraction of ammonia is 26% or 27%.
Further, the silane coupling agent is selected from one or more of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane and 3-aminopropyldimethylethoxysilane.
By selecting the silane coupling agent, not only can hydrolysis reaction be carried out to generate silicon dioxide to coat the surface of the ternary cathode material, but also amino groups can be grafted on the surface of the ternary cathode material. Further, the amino group can serve as a reaction site of an in-situ polymerization reaction in a subsequent reaction, improving the connection strength between the second connection layer comprising the conductive polymer and the first connection layer.
The reaction principle of step S1 of the present application is illustrated below by fig. 1:
the solid circles in fig. 1 represent the ternary positive electrode material core. Firstly, alkaline substances such as ammonia water are adopted to pretreat the ternary positive electrode material kernel, so that hydroxyl is grafted on the surface of the ternary positive electrode material kernel; and then, mixing the ternary positive electrode material kernel grafted with hydroxyl with a silane coupling agent, so that the silane coupling agent is subjected to hydrolysis reaction and forms covalent bond connection with the hydroxyl on the surface of the ternary positive electrode material kernel. Meanwhile, the selected silane coupling agent has aminopropyl and can graft amino groups on the surface of the core of the ternary cathode material. While the amino group can provide a reactive site for subsequent polymerization reactions.
When the hydroxyl groups on the surface of the core of the ternary positive electrode material are covalently bonded, the covalent bond may include a silicon-oxygen bond or another covalent bond. However, no matter what kind of covalent bond is, compared with the wrapping mode (wrapping a layer of wrapping layer on the surface of the ternary cathode material core) in the prior art, the connection mode of the covalent bond greatly improves the connection strength of the ternary cathode material core and the first protective layer.
Further, in some embodiments herein, the step of reacting the ternary positive electrode material with a silane coupling agent comprises:
and mixing the ternary cathode material with the dispersion liquid, adding an alkaline substance after uniform dispersion, mixing and uniformly dispersing, and then adding a silane coupling agent for reaction.
Further, the dispersant may be selected from alcohols, such as ethanol.
Further, the dispersion can be carried out in an ultrasonic dispersion mode, and further optionally, the ultrasonic dispersion time is 15-30 minutes.
Through dispersing the ternary cathode material, the first protection layer obtained by subsequent reaction can be more uniform, and the agglomeration is avoided.
Further, the ternary cathode material is a nickel-cobalt-manganese ternary cathode material, and the chemical formula of the ternary cathode material is Li (Ni) 1-x- y Co x Mn y )O 2 Wherein 0 is<x<1，0<y<1。
Furthermore, the particle size of the ternary cathode material is 3-20 μm.
Within the above particle diameter range, the first protective layer having better uniformity can be obtained.
Further optionally, the particle size of the ternary cathode material is 3.5 μm to 19 μm.
Further optionally, the particle size of the ternary cathode material is between 5 μm and 18 μm.
Further optionally, the particle size of the ternary cathode material is 6 μm to 15 μm.
Illustratively, the particle size of the ternary positive electrode material is 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, or 14 μm.
Further, in some embodiments, the above-mentioned basic substance is added dropwise.
Further, continuous stirring is carried out during the reaction of adding the silane coupling agent, and optionally, the stirring time is 1-2 h.
Further, after the completion of the reaction, centrifugal separation is also performed, and optionally centrifugal separation is performed using an alcohol such as ethanol.
Further, drying is carried out after centrifugal separation, and optionally, vacuum drying is adopted.
Further, the positive electrode material coated with the first protective layer is also ground after drying. Optionally, grinding to a particle size of 3 μm to 20 μm. Illustratively, the milling is to a particle size of 4 μm, 6 μm, 8 μm, 10 μm, 12 μm, 15 μm, or 18 μm.
And S2, carrying out in-situ polymerization reaction on the product obtained in the step S1 and a polymer monomer to generate a second protective layer connected to the surface of the first protective layer, wherein the material of the second protective layer comprises a conductive polymer.
Through connect the second protective layer that contains conductive polymer at first protective layer surface, can improve composite cathode material's electrochemical properties, and because the scheme second protective layer of this application is connected on first protective layer surface, consequently need not carry out high temperature carbonization, also can guarantee composite cathode material's stability and excellent electrochemical properties to can effectively improve lithium ion battery's electrochemical properties.
Further, as the scheme of the application does not need high-temperature carbonization treatment, compared with the conventional means in the field, the method greatly reduces the process complexity, simplifies the preparation steps and reduces the cost.
Further, the step of carrying out in-situ polymerization reaction of the product obtained in the step S1 and polymer monomers comprises:
and carrying out in-situ polymerization reaction on the positive electrode material connected with the first protective layer, a polymer monomer and an oxidant.
Further, the polymer monomer is selected from aniline.
In the scheme of this application, because first protective layer surface has aminopropyl, when the cathode material that will be connected with first protective layer carries out the normal position polymerization reaction with polymer monomer, oxidant, the aniline monomer can be preferentially with the aminopropyl reaction on the first protective layer to can form covalent bond connection with first protective layer, and then can greatly improve conducting polymer and the joint strength of first protective layer, and then also make the joint strength of second protective layer and ternary cathode material kernel higher.
Further, the mass concentration of the polymer monomer is 0.01mol/L to 0.05 mol/L.
Further alternatively, the species of polymeric monomer is present at a concentration of 0.015mol/L to 0.045 mol/L.
Further alternatively, the species concentration of the polymeric monomer is from 0.02mol/L to 0.04 mol/L.
Illustratively, the mass concentration of the above-mentioned polymer monomer is 0.025mol/L, 0.03mol/L, 0.035mol/L, or 0.04 mol/L.
Further, the oxidant is selected from ammonium persulfate.
Further optionally, the species of the oxidizing agent is present in a concentration of 0.02mol/L to 0.1 mol/L.
Further optionally, the species of the oxidizing agent is present in a concentration of 0.03mol/L to 0.09 mol/L.
Further optionally, the species of the oxidizing agent is present in a concentration of 0.04mol/L to 0.08 mol/L.
Illustratively, the species of the oxidizing agent is present in a concentration of 0.05mol/L, 0.06mol/L, 0.07mol/L, or 0.08 mol/L.
Further, before the in-situ polymerization reaction of the positive electrode material connected with the first protective layer, the polymer monomer and the oxidant, the positive electrode material connected with the first protective layer is dispersed.
Alternatively, the positive electrode material to which the first protective layer is attached is mixed with a dispersant ethanol solution, and then subjected to ultrasonic dispersion. Optionally, in the ethanol solution, the volume ratio of ethanol to water is 3: 1. Furthermore, the time of ultrasonic dispersion is 10-20 minutes. Illustratively, the dispersion time is 15 minutes.
In other alternative embodiments of the present application, other dispersants may also be selected.
By dispersing the positive electrode material connected with the first protective layer, the uniformity of the subsequent polymerization reaction can be improved, thereby obtaining a uniform conductive polymer layer.
Further, after the positive electrode material connected with the first protective layer is mixed with the polymer monomer, a dispersion treatment is further performed, and optionally, the dispersion treatment is performed in an ultrasonic manner. Optionally, the dispersing time is 10-20 minutes. Illustratively, the dispersion time is 15 minutes.
Further, the positive electrode material connected with the first protective layer and the polymer monomer are mixed, dispersed uniformly and then placed in a water bath at 0 ℃ to be continuously stirred.
Further, before the oxidizing agent is added into the reaction system, acid treatment is also carried out.
Alternatively, the oxidizing agent is dissolved in an acid solution and then placed in an ice bath to cool to 0 ℃.
Optionally, the acid is hydrochloric acid, and further optionally, the concentration of the hydrochloric acid is 1.2-1.8 mol/L.
Further, the polymerization reaction is carried out while continuously stirring for 3 to 4 hours.
Further, after the reaction is finished, the product is washed, optionally with ethanol. Optionally, the product is also dried after washing.
According to the method, the silicon dioxide intermediate layer generated by the hydrolysis reaction of the silane coupling agent can effectively inhibit the side reaction of the ternary core and the electrolyte, so that the cycling stability of the electrode is improved. Meanwhile, the amino group on the surface of the ternary material is used as an in-situ polymerization initiation site, and the silicon oxide coated ternary core and the conductive polymer polyaniline shell are connected in a covalent bond mode, so that the prepared anode material is uniform in carbon coating, does not need high-temperature carbonization, is excellent in cycling stability and conductivity, and can effectively improve the electrochemical performance. Along with the continuous accumulation of the cycle times, the core-shell structure is not easy to damage. Furthermore, the preparation method has the advantages that the reaction conditions are easy to control, no special requirements are required on equipment, and the operation is simple and convenient; compared with the traditional chemical deposition method, the synthetic route is simple and the cost is low; compared with a ball milling method and a solvothermal method, the synthesized composite material has high structural strength and good cycle stability.
Some embodiments of the present application provide a composite cathode material, which can be prepared by using the preparation method of the composite cathode material provided in any one of the foregoing embodiments.
Further, the composite positive electrode material includes: the core, first protective layer and second protective layer.
Further, the core of the composite cathode material is a ternary cathode material. Further, the first protective layer is connected to the surface of the inner core. Further, the material of the first protective layer includes silicon dioxide. Further, a second protective layer is connected to the surface of the first protective layer, and the material of the second protective layer comprises a conductive polymer.
Further, the first protective layer is connected with the ternary cathode material through a first covalent bond; optionally, the first covalent bond comprises a siloxane bond.
Further, the second protective layer is linked to the first protective layer by a second covalent bond.
Further, the conductive polymer is polyaniline. Optionally, the second covalent bond comprises a nitrogen-carbon bond.
Further, the ternary cathode material is a nickel-cobalt-manganese ternary cathode material with a chemical formula of Li (Ni) 1-x-y Co x Mn y )O 2 Wherein 0 is<x<1，0<y<1。
Optionally, the particle size of the ternary cathode material is 3 μm to 20 μm.
Further optionally, the nickel-cobalt-manganese ternary positive electrode material is selected from the model of NCM 523.
Some embodiments of the present application provide a lithium ion battery comprising the composite positive electrode material provided in any of the preceding embodiments; or the lithium ion battery comprises the composite cathode material prepared by the preparation method of the composite cathode material.
The features and properties of the present application are described in further detail below with reference to examples:
example 1
Providing a composite cathode material, and preparing according to the following steps:
(1) 0.2g of NCM523 ternary positive electrode material with the particle size of 3 mu m is added into 120ml of ethanol, and ultrasonic dispersion is carried out for 20 minutes. And then slowly dripping 2ml of ammonia water (the concentration is 14.5mol/L) and 10ml of deionized water into the stirred ternary material dispersion liquid under the stirring condition, adding 0.2ml of 3-aminopropyltriethoxysilane after dripping is finished, continuously stirring for 2 hours at room temperature, finally centrifuging for three times by using ethanol, drying in vacuum, and grinding to obtain the ternary cathode material with the first protective layer.
(2) And (2) ultrasonically dispersing 0.16g of the material prepared in the step (1) in 100ml of ethanol-water solution (the volume ratio is 3:1), ultrasonically treating for 15 minutes, adding 0.1ml of aniline, ultrasonically treating for 15 minutes, and then stirring in an ice bath at 0 ℃ to obtain a positive electrode material-aniline dispersion solution.
(3) And (3) dissolving 0.6g of ammonium persulfate in 4ml of 1.5mol/L hydrochloric acid aqueous solution, placing the solution in an ice bath to cool to 0 ℃, dropwise adding the solution into the positive electrode material-aniline dispersion solution prepared in the step (2), stirring and polymerizing for 3.5 hours, filtering and washing a product by using ethanol until a filtrate is colorless, and drying to prepare the composite positive electrode material.
Example 2
Providing a composite cathode material, and preparing according to the following steps:
(1) 0.2g of NCM523 ternary positive electrode material with the particle size of 10 mu m is added into 120ml of ethanol, and ultrasonic dispersion is carried out for 20 minutes. And then slowly dripping 2ml of ammonia water (the concentration is 14.5mol/L) and 10ml of deionized water into the stirred ternary material dispersion liquid under the stirring condition, adding 0.5ml of 3-aminopropyltriethoxysilane after dripping is finished, continuously stirring for 2 hours at room temperature, finally centrifuging for three times by using ethanol, drying in vacuum, and grinding to obtain the ternary cathode material with the first protective layer.
(2) And (2) dispersing 0.16g of the material prepared in the step (1) in 100ml of ethanol-water solution (volume ratio is 3:1), carrying out ultrasonic treatment for 15 minutes, adding 0.1ml of aniline, carrying out ultrasonic treatment for 15 minutes, and then placing in an ice bath at 0 ℃ for continuously stirring to obtain a positive electrode material-aniline dispersion solution.
(3) And (3) dissolving 0.6g of ammonium persulfate in 4ml of 1.5mol/L hydrochloric acid aqueous solution, placing the solution in an ice bath to cool to 0 ℃, dropwise adding the solution into the ternary material obtained in the step (II) and the ethanol-water dispersion of aniline, stirring and polymerizing for 3.5 hours, filtering and washing the product with ethanol until the filtrate is colorless, and drying to obtain the composite cathode material.
Example 3
Providing a composite cathode material, and preparing according to the following steps:
(1) 0.2g of NCM523 ternary positive electrode material with the particle size of 20 mu m is added into 120ml of ethanol, and ultrasonic dispersion is carried out for 20 minutes. Then slowly dropping 2ml of ammonia water (the concentration is 14.5mol/L) and 10ml of deionized water into the stirred ternary material dispersion liquid under stirring, adding 0.7ml of 3-aminopropyltriethoxysilane after dropping, continuously stirring for 2 hours at room temperature, finally centrifuging for three times by using ethanol, drying in vacuum, and grinding to obtain the ternary cathode material with the first protective layer.
(2) And (2) dispersing 0.16g of the material prepared in the step (1) in 100ml of ethanol-water solution (volume ratio is 3:1), carrying out ultrasonic treatment for 15 minutes, adding 0.1ml of aniline, carrying out ultrasonic treatment for 15 minutes, and then placing in an ice bath at 0 ℃ to continuously stir to obtain the anode material-aniline dispersion solution.
(3) And (3) dissolving 0.6g of ammonium persulfate in 4ml of 1.5mol/L hydrochloric acid aqueous solution, placing the solution in an ice bath to cool to 0 ℃, dropwise adding the solution into the positive electrode material-aniline dispersion solution prepared in the step (2), stirring and polymerizing for 3.5 hours, filtering and washing the product by using ethanol until the filtrate is colorless, and drying to obtain the composite positive electrode material.
Comparative example 1
A composite positive electrode material was provided, which was substantially the same as the preparation procedure of example 1 except that 3-aminopropyltriethoxysilane was not added in step (1).
Experimental example 1
The appearance of the composite cathode material prepared in example 1 is observed by a scanning electron microscope, and the result is shown in the attached figure 2 of the specification.
As can be seen from fig. 2, the composite cathode material prepared in example 1 forms a double-layer structure, and the thin first protective layer containing silicon dioxide can effectively avoid side reactions between the electrolyte and the ternary core; and the second protective layer containing the conductive polymer is connected with the first protective layer through covalent bonds, so that the connection strength is greatly improved. The problem of among the prior art carbon coating structural strength weak suffer destruction easily is solved.
Experimental example 2
The composite positive electrode materials provided in examples 1 to 3 and comparative example 1 were prepared into lithium ion batteries under the same conditions, and cycle performance was tested. The test results are shown in figure 3 of the specification.
As can be seen from fig. 3, the cycle performance of the composite positive electrode materials of examples 1 to 3 is significantly better than that of comparative example 1. Therefore, the scheme of adding 3-aminopropyltriethoxysilane can effectively improve the cycling stability of the material. Further, it can be seen from the cycle test results of examples 1 to 3 that the addition amount of 3-aminopropyltriethoxysilane increases continuously, and the battery capacity is improved to a certain extent, because the more the addition amount of 3-aminopropyltriethoxysilane increases, the more uniform the coating effect of the material and the conductive carbon layer is, the more uniform conductive network is formed, the more beneficial is to the transmission of lithium ions, and the capacity of the material is fully exerted. Further, it can be seen from the figure that as the addition amount of 3-aminopropyltriethoxysilane increases, the cycle stability is also improved because the more the addition amount of 3-aminopropyltriethoxysilane increases, the more stable the structure of the formed carbon coating layer is.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made to the present application by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims (14)

1. A composite positive electrode material, comprising:
the inner core is a ternary positive electrode material;
the first protective layer is connected to the surface of the inner core; the composition of the first protective layer comprises silicon dioxide; and
the second protective layer is connected to the surface of the first protective layer, the components of the second protective layer comprise conductive polymers, and the conductive polymers are polyaniline;
the first protective layer is connected with the ternary cathode material through a first covalent bond, and the first covalent bond comprises a silicon-oxygen bond;
the second protective layer is linked to the first protective layer by a second covalent bond, the second covalent bond comprising a nitrogen-carbon bond.
2. The composite positive electrode material according to claim 1,
the ternary positive electrode material is a nickel-cobalt-manganese ternary positive electrode material, and the chemical molecular formula is Li (Ni) 1-x-y Co x Mn y )O 2 Wherein 0 is<x<1，0<y<1; the particle size of the ternary cathode material is 3-20 μm.
3. A method for preparing the composite positive electrode material according to any one of claims 1 to 2, comprising:
reacting a ternary positive electrode material with a silane coupling agent, and hydrolyzing the silane coupling agent to generate a first protective layer connected to the surface of the ternary positive electrode material, wherein the first protective layer comprises silicon dioxide;
then carrying out in-situ polymerization reaction with polymer monomers to generate a second protective layer connected to the surface of the first protective layer, wherein the components of the second protective layer comprise conductive polymers.
4. The method for producing a composite positive electrode material according to claim 3,
the step of reacting the ternary cathode material with a silane coupling agent comprises:
modifying the ternary cathode material by using an alkaline substance to graft hydroxyl on the surface of the ternary cathode material;
then reacting with the silane coupling agent to hydrolyze the silane coupling agent to generate silica, and grafting aminopropyl on the silica.
5. The method for preparing the composite positive electrode material according to claim 4, wherein the silane coupling agent is one or more selected from the group consisting of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyldimethylethoxysilane.
6. The method for producing a composite positive electrode material according to claim 5,
the ratio of the amount of the silane coupling agent to the amount of the ternary positive electrode material is (1-10): 10.
7. The method for producing a composite positive electrode material according to claim 5,
the alkaline substance is selected from ammonia water.
8. The method for producing a composite positive electrode material according to claim 7,
the mass fraction of the ammonia water is 25-28%.
9. The method for producing a composite positive electrode material according to any one of claims 3 to 8,
said step of then carrying out an in situ polymerization reaction with a polymer monomer comprising:
and carrying out in-situ polymerization reaction on the positive electrode material connected with the first protective layer, a polymer monomer and an oxidant.
10. The method for producing a composite positive electrode material according to claim 9,
the mass concentration of the polymer monomer is 0.01mol/L to 0.05 mol/L.
11. The method for producing a composite positive electrode material according to claim 9,
the polymer monomer is aniline.
12. The method for producing a composite positive electrode material according to claim 9,
the oxidant is selected from ammonium persulfate.
13. The method for producing a composite positive electrode material according to claim 9,
the mass concentration of the oxidant is 0.02mol/L-0.1 mol/L.
14. A lithium ion battery comprising the composite positive electrode material according to any one of claims 1 to 2; or the lithium ion battery comprises the composite cathode material prepared by the preparation method of the composite cathode material according to any one of claims 3 to 13.
CN202110390281.6A 2021-04-12 2021-04-12 Composite cathode material, preparation method thereof and lithium ion battery Active CN113140715B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110390281.6A CN113140715B (en) 2021-04-12 2021-04-12 Composite cathode material, preparation method thereof and lithium ion battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110390281.6A CN113140715B (en) 2021-04-12 2021-04-12 Composite cathode material, preparation method thereof and lithium ion battery

Publications (2)

Publication Number Publication Date
CN113140715A CN113140715A (en) 2021-07-20
CN113140715B true CN113140715B (en) 2022-08-26

Family

ID=76810782

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110390281.6A Active CN113140715B (en) 2021-04-12 2021-04-12 Composite cathode material, preparation method thereof and lithium ion battery

Country Status (1)

Country Link
CN (1) CN113140715B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114497532A (en) * 2022-01-27 2022-05-13 蜂巢能源科技(马鞍山)有限公司 Cobalt-free positive electrode material and modification method and application thereof
CN114566641B (en) * 2022-02-28 2024-02-23 蜂巢能源科技股份有限公司 Positive electrode material and preparation method and application thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107394166A (en) * 2017-07-26 2017-11-24 广东天劲新能源科技股份有限公司 Nickel-cobalt lithium manganate cathode material of high security double-coating and preparation method thereof
CN107768617A (en) * 2017-09-15 2018-03-06 深圳启辰新能源科技有限公司 Lithium-sulfur battery composite anode material and preparation method thereof
CN108598388A (en) * 2018-03-23 2018-09-28 格林美（无锡）能源材料有限公司 A kind of C/SiO2Coat lithium electricity tertiary cathode material and preparation method thereof
CN111689527A (en) * 2020-06-22 2020-09-22 湖南金富力新能源股份有限公司 Preparation method of one-pot double-coated lithium ion battery NCM ternary cathode material
CN112164775A (en) * 2020-09-08 2021-01-01 合肥国轩高科动力能源有限公司 In-situ oxidative polymerization coated lithium ion ternary cathode material and preparation method thereof

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103526203B (en) * 2013-10-14 2015-08-12 天津大学 A kind of titanium base material surface refractory polymolecular layer boundary lubricant film and preparation method
US10833369B2 (en) * 2015-12-02 2020-11-10 Nec Corporation Positive electrode active substance for lithium secondary battery, positive electrode for lithium secondary battery and lithium secondary battery, and methods for producing these
EP3408884A4 (en) * 2016-01-25 2019-09-18 Hydro-Québec Core-shell electrode material particles and their use in electrochemical cells

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107394166A (en) * 2017-07-26 2017-11-24 广东天劲新能源科技股份有限公司 Nickel-cobalt lithium manganate cathode material of high security double-coating and preparation method thereof
CN107768617A (en) * 2017-09-15 2018-03-06 深圳启辰新能源科技有限公司 Lithium-sulfur battery composite anode material and preparation method thereof
CN108598388A (en) * 2018-03-23 2018-09-28 格林美（无锡）能源材料有限公司 A kind of C/SiO2Coat lithium electricity tertiary cathode material and preparation method thereof
CN111689527A (en) * 2020-06-22 2020-09-22 湖南金富力新能源股份有限公司 Preparation method of one-pot double-coated lithium ion battery NCM ternary cathode material
CN112164775A (en) * 2020-09-08 2021-01-01 合肥国轩高科动力能源有限公司 In-situ oxidative polymerization coated lithium ion ternary cathode material and preparation method thereof

Also Published As

Publication number Publication date
CN113140715A (en) 2021-07-20

Similar Documents

Publication Publication Date Title
Chen et al. Improved performance of lithium ion battery separator enabled by co-electrospinnig polyimide/poly (vinylidene fluoride-co-hexafluoropropylene) and the incorporation of TiO2-(2-hydroxyethyl methacrylate)
CN107069085B (en) A kind of flexible solid method for preparing polymer electrolytes and application
CN102888016B (en) Preparation method of lithium-ion secondary battery diaphragm with crosslinking composite layer
CN113140715B (en) Composite cathode material, preparation method thereof and lithium ion battery
CN109119574A (en) Porosity lithium ion battery separator and the preparation method and application thereof based on crosslinking with line polymer
WO2020034168A1 (en) Porous lithium ion battery separator film employing cross-linked polymer and linear polymer, preparation method and application thereof
CN114927753A (en) Composite solid electrolyte membrane, preparation method thereof and all-solid-state lithium metal battery
CN109167036B (en) TiN and conductive polymer composite modified lithium ion layered ternary positive electrode material and preparation method thereof
CN107482188A (en) A kind of hollow composite material of core-shell structure and preparation method and application
CN113054196B (en) Method for modifying positive active material of lithium slurry battery
CN110444752A (en) Extended-life lithium ion battery tertiary cathode material and its preparation method and application
CN112952202B (en) Crosslinked network SiO2Composite single-ion conductor electrolyte and preparation method and application thereof
CN110828795B (en) Zinc-manganese-oxygen cathode material and preparation method and application thereof
CN108933238A (en) Modified tertiary cathode material and its preparation method and application
CN112701292A (en) Lithium battery silicon-carbon negative electrode ball milling compounding method
CN110010361A (en) The preparation method of composite conducting slurry and the preparation method of electrode
CN113363560B (en) Organic in-situ interface modified solid electrolyte and preparation method thereof
CN110993367B (en) Spherical carbon @ manganese oxide @ carbon @ iron oxide composite material and preparation and application thereof
CN114079124B (en) Organic-inorganic composite lithium ion battery diaphragm and preparation method thereof
CN109980166B (en) Biomass nanofiber diaphragm and preparation method and application thereof
CN113793938A (en) PVDF binder for lithium battery/sodium battery/potassium battery positive electrode and preparation method thereof
CN113381123A (en) SiO (silicon dioxide)2Method for modifying meta-aramid lithium ion battery diaphragm by using nano particles
CN117199466B (en) High-conductivity composite membrane for vanadium redox flow battery and preparation method thereof
CN117106350B (en) Composite conductive coating and production method and application thereof
CN108735966A (en) The preparation method of lithium ion battery anode glue size

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant