CN116404108A - Positive plate and preparation method thereof, electrode assembly, energy storage device and electric equipment - Google Patents

Positive plate and preparation method thereof, electrode assembly, energy storage device and electric equipment Download PDF

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Publication number
CN116404108A
CN116404108A CN202310601245.9A CN202310601245A CN116404108A CN 116404108 A CN116404108 A CN 116404108A CN 202310601245 A CN202310601245 A CN 202310601245A CN 116404108 A CN116404108 A CN 116404108A
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lithium
rich manganese
active material
positive electrode
manganese
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谢炎崇
贺伟
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Xiamen Hithium Energy Storage Technology Co Ltd
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Xiamen Hithium Energy Storage Technology 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • 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
    • H01M10/54—Reclaiming serviceable parts of waste accumulators
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • 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
    • H01M4/48—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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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

Abstract

The application discloses an anode plate, a preparation method thereof, an electrode assembly, energy storage equipment and electric equipment. The positive plate comprises a current collector and a composite active material coated on the surface of the current collector, wherein the composite active material comprises an inner core and a shell layer coated on the surface of the inner core, the inner core comprises a first lithium-rich manganese-based material, the shell layer comprises a second lithium-rich manganese-based material, the first lithium-rich manganese-based material is a lithium-rich manganese-based reclaimed material obtained through a reclaiming treatment process, and the second lithium-rich manganese-based material is a newly prepared lithium-rich manganese-based material; the average grain diameter of the inner core is 0.08-0.5 times of the average grain diameter of the composite active material. The positive electrode active material realizes waste recycling, and has good compatibility because the inner core and the shell are of the same type, the preparation is convenient, the battery is ensured to have higher capacity performance, the cost of the positive electrode material is reduced, and high economic value is obtained.

Description

Positive plate and preparation method thereof, electrode assembly, energy storage device and electric equipment
Technical Field
The invention relates to the field of new energy, in particular to a positive plate, a preparation method thereof, an electrode assembly, energy storage equipment and electric equipment.
Background
The production process of the lithium battery can generate a large amount of positive plate waste, such as serious waste in a cutting process; the lithium battery made of the lithium-rich manganese-based positive electrode material has the production cost more than three times that of the lithium iron phosphate material, so that the lithium-rich manganese-based reclaimed material is introduced as the positive electrode active material, and the battery performance is improved, and the lithium battery has high economic value.
Disclosure of Invention
In view of the foregoing drawbacks or shortcomings in the prior art, it is desirable to provide a positive electrode sheet, a method of manufacturing the same, an electrode assembly, an energy storage device, and an electrical device.
In a first aspect, the application provides a positive plate, which comprises a current collector and a composite active material coated on the surface of the current collector, wherein the composite active material comprises an inner core and a shell layer coated on the surface of the inner core, the inner core comprises a first lithium-rich manganese-based material, and the shell layer comprises a second lithium-rich manganese-based material, wherein the first lithium-rich manganese-based material is a lithium-rich manganese-based reclaimed material obtained through a recycling process, and the second lithium-rich manganese-based material is a newly prepared lithium-rich manganese-based material; the average grain diameter of the inner core is 0.08-0.5 times of the average grain diameter of the composite active material.
Alternatively, the composite active material has an average particle size of 5um to 8um.
As an alternative scheme, the average grain diameter of the first lithium-rich manganese-based metamaterial is 0.4um to 1.2um; preferably, the average particle size of the first lithium-rich manganese-based material is 0.8um to 1.0um.
Alternatively, the active material has the formula xLi 2 MnO 3 (1-x)LiMO 2 Wherein m=ni or Mn,0<x<1。
In a second aspect, the present application provides a method for preparing the positive electrode sheet of the first aspect, including the following steps:
separating the scrapped lithium-rich manganese-based positive plate to obtain an active material containing lithium-rich manganese-based;
performing ball milling treatment on the active material containing the lithium-rich manganese base, and drying to obtain first lithium-rich manganese base material powder;
preparing a mixed metal salt solution containing manganese salt and M metal salt, a precipitator solution and a complexing agent solution;
mixing the first lithium-rich manganese-based material powder, the mixed metal salt solution, the precipitant solution and the complexing agent solution to obtain a mixed solution, placing the mixed solution into a reaction kettle for precipitation and chemical combination reaction, and performing solid-liquid separation, washing and drying to obtain a composite active material precursor;
mixing the precursor of the composite active material with a carbon source and a lithium source for heat treatment to obtain the composite active material;
mixing the composite active material, the positive electrode conductive agent and the binder according to the mass ratio of (85% -95%) (1% -5%) with solvent NMP to obtain positive electrode slurry, coating and drying on aluminum foil, rolling and cutting to obtain the positive electrode plate.
As an alternative, the process of separating the scrapped lithium-rich manganese-based positive electrode sheet to obtain the active material containing the lithium-rich manganese-based comprises the following steps:
and immersing the scrapped lithium-rich manganese-based positive plate in deionized water until the aluminum foil is separated from the active material containing the lithium-rich manganese-based to obtain the active material containing the lithium-rich manganese-based.
As an alternative scheme, the active material containing the lithium-rich manganese base is subjected to ball milling treatment and is dried, and in the process of obtaining the first lithium-rich manganese base material powder, a spray drying mode is adopted as a drying mode.
As an alternative scheme, the first lithium-rich manganese-based material powder, the mixed metal salt solution, the precipitant solution and the complexing agent solution are mixed to obtain a mixed solution, and the mixed solution is placed into a reaction kettle to carry out precipitation and chemical combination reaction, wherein the PH value of the mixed solution is kept at 10-12, the temperature of the precipitation and chemical combination reaction is 100-120 ℃, and the time is 5-10 h.
As an alternative scheme, in the process of mixing the precursor of the composite active material with a carbon source and a lithium source for heat treatment to obtain the composite active material, the heat treatment temperature is 700-750 ℃ and the time is 3-5 h.
In a third aspect, the present application provides an electrode assembly comprising the positive electrode sheet of the first aspect.
In a fourth aspect, the present application provides an energy storage device comprising the positive electrode sheet of the first aspect or the electrode assembly of the third aspect.
In a fifth aspect, the present application provides a powered device, the powered device comprising the energy storage device of the fourth aspect, the energy storage device powering the powered device.
According to the positive plate provided by the invention, the recovered lithium-rich manganese-based reclaimed material is used as the inner core, and the newly prepared lithium-rich manganese-based material is used as the shell layer, so that the composite positive plate is obtained, and the problems of high cost and poor performance of the conventional lithium-rich manganese-based reclaimed material battery are solved. The composite active material takes the lithium-rich manganese-based reclaimed material as the inner core, and the shell layer is the newly prepared lithium-rich manganese-based material, so that waste recycling is realized, and the inner core and the shell layer are the same type of material, so that the inner core and the shell layer have good compatibility, the preparation is convenient, the battery is ensured to have higher capacity performance, the cost of the anode material is reduced, and the high economic value is obtained.
Drawings
Other features, objects and advantages of the present application will become more apparent upon reading of the detailed description of non-limiting embodiments, made with reference to the following drawings, in which:
FIG. 1 is a graph showing the particle size distribution of the lithium-rich manganese-based reclaimed material and the composite active material thereof in example 1 of the present invention;
FIG. 2 is a particle morphology of the composite active material of example 1 of the present invention;
fig. 3 is an XRD pattern of the composite active material of example 1 of the present invention.
Detailed Description
The present application is described in further detail below with reference to examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention.
It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The present application will be described in detail with reference to examples.
In a first aspect, an embodiment of the present invention provides a positive electrode sheet, including a current collector and a composite active material coated on a surface of the current collector, where the composite active material includes a core and a shell layer coated on a surface of the core, the core includes a first lithium-rich manganese-based material, and the shell layer includes a second lithium-rich manganese-based material, where the first lithium-rich manganese-based material is a recovered lithium-rich manganese-based material obtained through a recovery process, and the second lithium-rich manganese-based material is a newly prepared lithium-rich manganese-based material; the average grain diameter of the inner core is 0.08-0.5 times of the average grain diameter of the composite active material.
It is understood that the current collector may be aluminum foil or copper foil, etc.; the embodiments of the present application are not limited in this regard.
When the particle size of the lithium-rich manganese-based material is relatively large, lithium ions in the lithium-rich manganese-based material are generally difficult to participate in electrochemical reaction, so that dead lithium is formed, the newly prepared lithium-rich manganese-based material is used as a shell layer to be coated on the surface of the lithium-rich manganese-based material by taking the lithium-rich manganese-based material as an inner core, the lithium-rich manganese-based material and the shell layer are compatible, the preparation method is simple, recycling of waste materials is realized, the generation cost is reduced, high economic value is obtained, and meanwhile, the excellent battery performance of the composite positive electrode material is ensured.
Wherein the lithium-rich manganese-based material is used as a substance, and can be specifically any existing lithium-rich manganese-based material with any structural formula, for example, xLi 2 MnO 3 (1-x)LiNi 0.5 Mn 0.5 O 2 、Li 2 MnO 3 LiNi 1-x Mn x O 2 Wherein 0 is<x<1, the specific structure of the three substances is not limited in the embodiment of the application.
It can also be understood that the lithium-rich manganese-based reclaimed material is used as a core to mainly support the newly prepared lithium-rich manganese-based material coated by the outer layer, so that the use of the newly prepared lithium-rich manganese-based material is reduced, and the cost of the positive plate is reduced, and therefore, in order to ensure that the composite active material has good battery performance, the particle size of the core is not easy to be excessively large. The particle size of the core in the embodiments of the present application is 0.08-0.5 times the particle size of the composite active material, and may be, for example, 0.08, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, or 0.5, etc. The particle size herein refers to an average particle size, and in a specific embodiment, the particle size may be represented by a D50 size, where D50 is the median particle size, that is, the median particle size corresponds to the cumulative particle size distribution of a sample at 50%.
The size of the inner core of the embodiment of the application is beneficial to ensuring that the newly prepared lithium-rich manganese-based material of the shell layer can reliably cover the inner core of the lithium-rich manganese-based reclaimed material while reducing the cost of the composite active material, so that the newly prepared lithium-rich manganese-based material is ensured to have better performance and good battery performance.
The positive plate solves the problems that the existing lithium-rich manganese-based positive electrode material is high in cost and the performance of the lithium-rich manganese-based reclaimed material battery is poor. According to the composite active material, the lithium-rich manganese-based reclaimed material is used as the inner core, the shell layer is the newly prepared lithium-rich manganese-based material, waste recycling is achieved, and the inner core and the shell layer are of the same type, so that the inner core and the shell layer have good compatibility, the preparation is convenient, the battery is guaranteed to have higher capacity performance, the cost of the anode material is reduced, and high economic value is obtained.
As a preferred embodiment, the composite active material has an average particle size of 5um to 8um. The average particle size of the composite active material is generally expressed by the size of D50. Wherein the average particle size of the composite active material may be 5um, 6um, 7um or 8um. The average particle size range of the composite active material in the embodiment is favorable for ensuring that the composite active material has good battery performance, avoiding that the composite material has too small particle size, the newly prepared lithium-rich manganese-based material has poor wrapping effect on the lithium-rich manganese-based reclaimed material, and the lithium-rich manganese-based reclaimed material with poor electrical performance can participate in electrochemical reaction due to the occurrence of gaps, thereby reducing the overall electrical performance of the composite active material, avoiding that the particle size is too large, causing too thick positive plate, increasing lithium ion diffusion path, being unfavorable for fully playing the characteristics of the composite active material and further leading to the reduction of the electrical performance of the material.
In a preferred embodiment, the first lithium-rich manganese-based material has an average particle size of 0.4um to 1.2um; preferably, the average particle size of the first lithium-rich manganese-based material is 0.8um to 1.0um. Wherein the average particle size of the first lithium-rich manganese-based material, i.e., the lithium-rich manganese-based recycle material, may be 0.4um, 0.5um, 0.6um, 0.7um, 0.8um, 0.9um, 1.0um, 1.1um, or 1.2um. The average particle size of the lithium-rich manganese-based reclaimed material is favorable for ensuring that the composite active material has good battery performance, and simultaneously ensuring that the newly prepared lithium-rich manganese-based reclaimed material can be reliably coated, so that the cost of the composite active material is reduced. When the average grain diameter of the first lithium-rich manganese-based material is smaller than 0.4um, the newly prepared lithium-rich manganese-based material cannot be reliably prepared, so that the battery performance of the composite material is reduced, when the average grain diameter of the first lithium-rich manganese-based material is larger than 1.2um, the coating effect of the newly prepared lithium-rich manganese-based material of the outer layer is relatively poor, and the performance of the composite active material is fully exerted due to the fact that the particle size of the first lithium-rich manganese-based material is too large, so that the battery performance is reduced.
As a realizable mode, the chemical formula of the composite active material is xLi 2 MnO 3 (1-x)LiMO 2 Wherein m=ni or Mn,0<x<1。
In summary, the composite active material of the application uses the lithium-rich manganese-based reclaimed material as the core and the shell layer as the newly prepared lithium-rich manganese-based material, so that waste recycling is realized, and the core and the shell layer are the same type of material, so that the core and the shell layer have good compatibility, the preparation is convenient, the higher capacity performance of the battery is ensured, the cost of the anode material is reduced, and the high economic value is obtained.
In a second aspect, the present application provides a method for preparing the positive electrode sheet of the first aspect, including the following steps:
s1, separating the scrapped lithium-rich manganese-based positive plate to obtain an active material containing a lithium-rich manganese base;
it will be appreciated that the scrapped lithium-rich manganese-based positive electrode sheet may be separated and subjected to a liquid soaking method, such as soaking in water or ethanol; of course, a mechanical separation method may also be used, for example, scraping the active material containing the lithium-rich manganese group directly from the positive electrode sheet, which is not particularly limited in the embodiments of the present application.
S2, performing ball milling treatment on the active material containing the lithium-rich manganese base, and drying to obtain first lithium-rich manganese base material powder;
wherein, the ball milling treatment adopts a wet ball milling mode, and ethanol, water or a mixture of ethanol and water can be added; in the actual preparation process, the ball-material ratio of ball milling treatment is (3-5): 2, the rotating speed is 1600r/min-2000r/min, and the time is 15h-20h; the active material containing the lithium-rich manganese-based material can be crushed and dispersed through ball milling treatment, and the active material is crushed to a proper particle size, so that the composite active material is conveniently prepared;
and drying the ball-milled material, evaporating the solvent or other volatile components in the ball-milled material, and further purifying the ball-milled material, so that the subsequent use is convenient. The drying method may be vacuum drying, air drying or spray drying.
S3, preparing a mixed metal salt solution containing manganese salt and M metal salt, and a precipitant solution and a complexing agent solution;
wherein the manganese salt and the M metal salt may be at least one of sulfate, nitrate and chloride. For example: manganese sulfate, manganese nitrate, manganese chloride, nickel sulfate, nickel nitrate, nickel chloride, cobalt sulfate, cobalt nitrate, and cobalt chloride; the concentration of the mixed metal salt solution can be 1.5mol/L to 3mol/L; in the actual configuration process, the mixed metal salt solution can be used according to xLi 2 MnO 3 (1-x)LiMO 2 (0<x<1) The stoichiometric ratio required in (2) is calculated;
the precipitant comprises at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate and ammonium bicarbonate, and the concentration of the precipitant can be 0.7mol/L to 1.5mol/L; the complexing agent can be ammonia water, and can be at least one of acid solution (hydrofluoric acid, ethylenediamine tetraacetic acid, acetic acid, lactic acid, salicylic acid, tartaric acid, succinic acid or sulfosalicylic acid), salt solution (hydrofluoric acid sodium salt, hydrofluoric acid potassium salt, hydrofluoric acid ammonium salt, ethylenediamine tetraacetic acid disodium salt, ethylenediamine tetraacetic acid potassium salt or ethylenediamine tetraacetic acid ammonium salt and the like), ethylenediamine and 2-methyl-8 hydroxyquinoline; the concentration of the complexing agent may be 0.1mol/L to 0.5mol/L. The embodiments of the present application are not specifically limited to the above,
s4, mixing the first lithium-rich manganese-based material powder, the mixed metal salt solution, the precipitant solution and the complexing agent solution to obtain a mixed solution, placing the mixed solution into a reaction kettle for precipitation and chemical combination reaction, and performing solid-liquid separation, washing and drying to obtain a precursor of the composite active material;
the mixed solution of the first lithium-rich manganese-based material powder, the mixed metal salt solution, the precipitator solution and the complexing agent solution is subjected to precipitation reaction, the mixed metal salt solution, the complexing agent and the precipitator are respectively injected into a reaction kettle containing the first lithium-rich manganese-based material powder in a parallel flow mode at a certain flow rate, and stirring is carried out in the reaction kettle, so that a lithium-rich manganese precursor with a relatively regular morphology can be formed, and the electrochemical performance of the lithium-rich manganese-based material is improved. The mixed metal salt solution, the complexing agent and the precipitant can be pumped into the reaction kettle by a pump; wherein the stirring rate may be 1500r/min to 3000r/min.
And (3) carrying out solid-liquid separation on the product after the reaction, washing and drying the solid to obtain the precursor of the composite active material.
S5, mixing the precursor of the composite active material with a carbon source and a lithium source for heat treatment to obtain the composite active material;
wherein the carbon source can be glucose, sucrose or starch; the lithium source can be at least one of lithium carbonate and lithium hydroxide monohydrate, and the dosage of the lithium source can be according to xLi 2 MnO 3 (1-x)LiMO 2 (0<x<1) The stoichiometric ratio required in (1) is calculated, in a specific embodiment, the mass ratio of the lithium source to the precursor of the composite active material may be 0.5-1.5:1; the embodiments of the present application are not particularly limited thereto.
After sintering, the lithium-rich manganese-based material obtained after sintering can be crushed and screened to be more convenient to use as a positive electrode material. The average particle diameter of the sieved lithium-rich manganese-based material is 5um.
S6, stirring the composite active material, the positive electrode conductive agent and the adhesive (1% -5%) with the solvent NMP according to the mass ratio (85% -95%), mixing the slurry to obtain positive electrode slurry, coating and drying the positive electrode slurry on aluminum foil, rolling and cutting to obtain the positive electrode plate.
The positive electrode conductive agent can be conductive carbon black, carbon nano tube or graphene and the like; the thickness of the aluminum foil is 10um-20um, for example, 10um, 12um, 15um, 17um or 20um, etc.
In the preparation method, the active material containing the lithium-rich manganese-based material is obtained by separating the scrapped positive plate and ball milling, and compared with the existing recovery method of sintering purification or strong acid and alkali dissolution, the preparation method is simple to operate, low in recovery cost and free from environmental pollution; the recovered lithium-rich manganese-based reclaimed material, the mixed metal salt solution, the precipitant and the complexing agent are reacted, and then heat treatment is carried out, so that the novel preparation of the lithium-rich manganese-based material on the surface growth part of the lithium-rich manganese-based reclaimed material is facilitated, the operation is simple and reliable, and the electrochemical performance of the material can be ensured.
As a realizable manner, the process of separating the scrapped lithium-rich manganese-based positive electrode sheet to obtain the active material containing the lithium-rich manganese-based comprises the following steps:
and immersing the scrapped lithium-rich manganese-based positive plate in deionized water until the aluminum foil is separated from the active material containing the lithium-rich manganese-based to obtain the active material containing the lithium-rich manganese-based.
The implementation mode is simple to operate, and is nontoxic and harmless.
As a realizable mode, the active material containing the lithium-rich manganese base is subjected to ball milling treatment and is dried, and in the process of obtaining the first lithium-rich manganese base material powder, a spray drying mode is adopted as a drying mode.
In the embodiment, the adoption of the spray drying mode is beneficial to ensuring that the obtained lithium-rich manganese-based reclaimed material cannot agglomerate in the drying process, ensuring that the reclaimed material has good dispersibility in the drying process, forming approximately spherical particles after drying, and being beneficial to the coating of the subsequent composite active material.
Further, in some embodiments, the first lithium-rich manganese-based material powder, the mixed metal salt solution, the precipitant solution and the complexing agent solution are mixed to obtain a mixed solution, and the mixed solution is placed in a reaction kettle to perform a precipitation and chemical combination reaction, wherein the pH value of the mixed solution is kept at 10-12, the temperature of the precipitation and chemical combination reaction is 100-120 ℃, and the time is 5-10 hours.
The PH value, the reaction temperature and the reaction time in the embodiment can lead the prepared precursor of the composite active material to form a precursor with regular morphology, thereby being beneficial to the preparation of the composite positive electrode material with better electrochemical performance.
As a realizable mode, in the process of mixing the precursor of the composite active material with a carbon source and a lithium source and performing heat treatment to obtain the composite active material, the heat treatment temperature is 700-750 ℃ and the time is 3-5 h. The temperature and time of the embodiment are favorable for forming the composite anode material with the core-shell structure, so that the newly prepared lithium-rich manganese-based material can be completely coated on the surface of the lithium-rich manganese-based reclaimed material, and further, the composite anode material is ensured to have good electrochemical performance.
Illustratively, in a specific embodiment, the method for preparing a lithium ion battery is as follows:
preparing a positive plate:
s1, 95% of: 2%: weighing corresponding amounts of lithium-rich manganese-based composite anode material, conductive carbon black and polyvinylidene fluoride in a stirring tank, and adding a proper amount of N-methylpyrrolidone (NMP) to stir for 6 hours to obtain uniform slurry with proper viscosity;
s2, uniformly coating the slurry on an aluminum foil in an extrusion coating mode to form a coating layer, fully drying in an oven to obtain a positive plate, putting the positive plate into a press machine for pressing, and then intercepting a positive plate wafer with the diameter of 15mm by adopting a puncher;
preparing a negative plate:
s3, 95% of: 2.5%:2.5 percent of artificial graphite, conductive carbon black and sodium carboxymethylcellulose with corresponding amounts are weighed in a stirring tank, and a proper amount of deionized water is added to stir for 6 hours to obtain uniform slurry with proper viscosity; coating the slurry on copper foil with the thickness of 10 mu m, putting the copper foil into a vacuum oven, drying the copper foil at 150 ℃ for 20 hours to obtain a negative plate, putting the negative plate into a press machine for pressing, and then intercepting a negative wafer with the diameter of 18mm by adopting a puncher;
preparation of a cell
The positive electrode wafer and the negative electrode wafer are placed in a glove box filled with an argon protective atmosphere for battery assembly, wherein 1mol/L lithium hexafluorophosphate is used for dissolving in the following molar ratio of 1:1 and diethyl carbonate as electrolyte; and assembling the anode wafer, the cathode wafer, the polyethylene diaphragm and other components together, then injecting electrolyte, and finally preparing the lithium ion battery.
In a third aspect, embodiments of the present invention provide an electrode assembly comprising the positive electrode sheet of the first aspect. Thus, the electrode assembly has all the features and advantages of the positive electrode sheet described above, and will not be described in detail herein.
In a fourth aspect, embodiments of the present application provide an energy storage device including the positive electrode sheet of the first aspect or the electrode assembly of the third aspect. Therefore, the energy storage device has all the features and advantages of the positive plate, and the details are not repeated here. In general, the energy storage device has high capacity performance and safety performance.
The energy storage device may be a lithium ion battery, and the anode material of the lithium ion battery may be any anode material, for example, a silicon-based anode, a metal lithium anode, a carbon anode, and the like, which is not limited in the embodiments of the present application.
In a fifth aspect, an embodiment of the present application provides an electrical device, where the electrical device includes the energy storage device of the fourth aspect, and the energy storage device supplies power to the electrical device. For example, the powered device may include a plurality of battery packs formed from the lithium-ion batteries described above. The electric device can be a lighting lamp, etc., so that it is known that the electric device has all the features and advantages of the positive plate described above, and the details are not repeated here.
The present invention will be illustrated by the following examples, which are given for illustrative purposes only and are not intended to limit the scope of the present invention in any way, and unless otherwise specified, the conditions or procedures not specifically described are conventional and the reagents and materials employed are commercially available.
Example 1:
(1) Preparation of a positive plate:
immersing the scrapped lithium-rich manganese-based positive plate in deionized water to separate the active material containing the lithium-rich manganese-based from the aluminum foil, thereby obtaining the active material containing the lithium-rich manganese-based;
performing ball milling treatment on the active material containing the lithium-rich manganese base, and performing spray drying to obtain first lithium-rich manganese base material powder, wherein the Dv50 of the first lithium-rich manganese base material powder is 0.4um as shown in figure 1; wherein the ball material ratio is 5:2, the rotating speed is 1600r/min, the time is 20h, the lower the ball material ratio is, the higher the rotating speed is, the longer the time is, and the smaller the particle size obtained by ball milling is; the pump speed of spray drying is 15mL/min, and the set temperature is 200 ℃;
according to xLi 2 MnO 3 (1-x)LiMO 2 (0<x<1) The stoichiometric ratio required in the process is to prepare a mixed metal salt solution containing manganese salt and M metal salt, prepare 0.7mol/L sodium hydroxide solution and prepare 0.1mol/L ammonia water solution; wherein the concentration of the mixed metal salt solution is 1.5mol/L;
mixing the first lithium-rich manganese-based material powder, the mixed metal salt solution, the precipitant solution and the complexing agent solution to obtain a mixed solution, placing the mixed solution into a reaction kettle, stirring to perform precipitation and chemical combination reaction, and performing solid-liquid separation, washing and drying to obtain a precursor of the composite active material; wherein the stirring speed is 1500r/min, the pH value of the mixed solution is 10-12, the reaction temperature is 100 ℃, and the reaction time is 5h;
mixing a precursor of the composite active material with glucose and lithium carbonate according to a mass ratio of 80:15:5, and performing heat treatment to obtain the composite active material; wherein the heat treatment temperature is 700 ℃ and the time is 3 hours.
The obtained composite active material is ground and then subjected to particle size distribution test, the result is shown in figure 1, and the particle size Dv50 is about 5-8 um; the electron microscope photograph is shown in figure 2, and the composite anode material is in a core-shell structure; the XRD results are shown in FIG. 3, where the composite positive electrode material is mainly a main crystal phase of a lithium-rich manganese-based material, and the ratio of the intensities of the main crystal planes I003/I104 is about 1.530 to 1.535.
It should be noted that:
dv50 test: measuring the particle size distribution by using a laser diffraction particle size distribution measuring instrument (Malvern Mastersizer 3000) according to a particle size distribution laser diffraction method GB/T19077-2016 to obtain Dv50;
XRD measurement: the method comprises the steps of testing by using a copper target (lambda=0.154 nm) through an X-ray diffractometer (D500 Siemens), wherein the scanning speed is 3 degrees/min, the scanning angle is 10-90 degrees, and a CuK alpha radioactive source is adopted as a radioactive source;
mixing 95% by mass of composite active material, 2% by mass of conductive carbon black and 3% by mass of polyvinylidene fluoride with NMP solvent to obtain positive electrode slurry, coating the positive electrode slurry on 15um thick aluminum foil, drying in a vacuum oven at 150 ℃, rolling and cutting to obtain a positive electrode plate;
(2) Preparing a negative plate:
stirring artificial graphite, conductive carbon black and sodium carboxymethylcellulose according to the mass ratio of 95% to 2.5% to obtain negative electrode slurry, coating the slurry on copper foil with the thickness of 10um, drying, rolling, and cutting to obtain a negative electrode plate;
(3) Preparation of a lithium ion battery:
the positive electrode plate and the negative electrode plate are placed in a glove box filled with argon protective atmosphere for battery assembly, wherein 1mol/L lithium hexafluorophosphate is used for dissolving in the following molar ratio of 1:1 and diethyl carbonate as electrolyte; and assembling the positive plate, the negative plate, the polyethylene diaphragm and other components together, then injecting electrolyte, and finally preparing the button type lithium ion battery.
Example 2
Unlike example 1 above, the sphere-to-material ratio was 5:2, the rotational speed was 1700r/min, the time was 20 hours, and the Dv50 of the first lithium-rich manganese-based material powder in this example was 0.6um;
example 3
Unlike example 1 above, the sphere-to-material ratio was 5:2, the rotational speed was 1800r/min, the time was 20 hours, and the Dv50 of the first lithium-rich manganese-based material powder in this example was 0.8um;
example 4
Unlike example 1 above, the sphere to material ratio was 5:2, the rotational speed was 1900r/min, the time was 20 hours, and the Dv50 of the first lithium-rich manganese-based material powder in this example was 1.0um;
example 5
Unlike example 1 above, the sphere to material ratio was 5:2, the rotational speed was 2000r/min, the time was 20 hours, and the Dv50 of the first lithium-rich manganese-based material powder in this example was 1.2um;
example 6
Unlike example 1 above, the heat treatment temperature was 500 ℃ for 3 hours and the Dv50 of the composite positive electrode active material in this example was 1um;
example 7
Unlike example 1 above, the heat treatment temperature was 900 ℃ for 3 hours and the Dv50 of the composite positive electrode active material in this example was 15um;
comparative example 1
Unlike example 1 described above, in this comparative example, the first lithium-rich manganese-based material powder having Dv50 of 5um to 8um was directly used as the positive electrode active material;
the following describes the lithium ion battery performance test procedure and test results:
(1) Rate discharge capacity
The lithium batteries prepared in examples and comparative examples were charged to 4.5V at 0.5C rate at 25 ℃, and then discharged to 3V at 0.5C rate, and the 0.5C discharge capacity was recorded at this time; then charging to 4.5V at 1C multiplying power, discharging to 3V at 1C multiplying power, and recording the discharge capacity as 1C at the moment;
(2) Cycle performance test
The lithium batteries prepared in examples and comparative examples were charged to 4.5V at 1C rate and then discharged to 3V at 1C rate at 25C, and the capacity of the 1 st turn was taken as an initial capacity, and the capacity of the 200 th turn was divided by the initial capacity to obtain a retention rate value.
The results of testing the lithium ion batteries of examples 1 to 7 and comparative example 1 according to the above procedure and method are shown in table 1:
table 1 test results for examples 1-7 and comparative example 1
Figure BDA0004251387800000141
Figure BDA0004251387800000151
According to the results shown in table 2:
the rate performance and cycle performance of the lithium ion batteries of examples 1 to 7 were significantly due to the lithium ion battery of comparative example 1, compared to comparative example 1; the composite positive electrode material disclosed by the application can effectively improve the multiplying power performance and the cycle performance of a lithium ion battery by coating the newly prepared lithium-rich manganese-based material with the lithium-rich manganese-based reclaimed material;
according to the test results of the lithium ion battery in the embodiments 1-5, it can be seen that the composite positive electrode material takes the lithium-rich manganese-based reclaimed material as the inner core, when the particle size of the lithium-rich manganese-based reclaimed material powder is gradually increased, the performance of the lithium ion battery is firstly increased and then decreased, which means that the particle size range of the lithium-rich manganese-based reclaimed material disclosed by the application is favorable for ensuring the excellent rate performance and the cycle performance of the battery, and when the particle size of the lithium-rich manganese-based reclaimed material is too large, the coating effect of the normal lithium-rich manganese-based material of the outer layer is relatively poor, and the particle size is too large, which also influences the full play of the material characteristics.
As can be seen from the test results of the lithium ion batteries of example 1, example 6 and example 7, the rate capability and the cycle performance of example 6 and example 7 are lower than those of example 1, which means that the too large or too small particle size of the composite positive electrode material can reduce the rate capability and the cycle performance of the lithium ion battery, and the particle size range of the composite positive electrode material of the embodiment of the present application is beneficial to improving the rate capability and the cycle performance of the battery.
The foregoing description is only of the preferred embodiments of the present application and is presented as a description of the principles of the technology being utilized. It will be appreciated by persons skilled in the art that the scope of the invention referred to in this application is not limited to the specific combinations of features described above, but it is intended to cover other embodiments in which any combination of features described above or equivalents thereof is possible without departing from the spirit of the invention. Such as the above-described features and technical features having similar functions (but not limited to) disclosed in the present application are replaced with each other.

Claims (12)

1. The positive plate is characterized by comprising a current collector and a composite active material coated on the surface of the current collector, wherein the composite active material comprises an inner core and a shell layer coated on the surface of the inner core, the inner core comprises a first lithium-rich manganese-based material, the shell layer comprises a second lithium-rich manganese-based material, the first lithium-rich manganese-based material is a lithium-rich manganese-based reclaimed material obtained through a reclaiming treatment process, and the second lithium-rich manganese-based material is a newly prepared lithium-rich manganese-based material; the average particle diameter of the inner core is 0.08-0.5 times of the average particle diameter of the composite active material.
2. The positive electrode sheet according to claim 1, wherein the composite active material has an average particle diameter of 5um to 8um.
3. The positive electrode sheet of claim 1, wherein the first lithium-rich manganese-based material has an average particle size of 0.4um to 1.2um; preferably, the average particle size of the first lithium-rich manganese-based material is 0.8um to 1.0um.
4. The positive electrode sheet according to claim 1, wherein the active material has a chemical formula of xLi 2 MnO 3 (1-x)LiMO 2 Wherein m=ni or Mn,0<x<1。
5. A method for producing the positive electrode sheet according to any one of claims 1 to 4, comprising the steps of:
separating the scrapped lithium-rich manganese-based positive plate to obtain an active material containing lithium-rich manganese-based;
ball milling is carried out on the active material containing the lithium-rich manganese base, and drying is carried out, so that the first lithium-rich manganese base material powder is obtained;
preparing a mixed metal salt solution containing manganese salt and M metal salt, a precipitator solution and a complexing agent solution;
mixing the first lithium-rich manganese-based material powder, the mixed metal salt solution, the precipitator solution and the complexing agent solution to obtain a mixed solution, placing the mixed solution into a reaction kettle for precipitation and chemical combination reaction, and performing solid-liquid separation, washing and drying to obtain a precursor of the composite active material;
mixing the composite active material precursor with a carbon source and a lithium source for heat treatment to obtain the composite active material;
and (3) stirring the composite active material, the positive electrode conductive agent and the binder with a solvent NMP according to the mass ratio of (1% -5%) to obtain positive electrode slurry, coating and drying the positive electrode slurry on aluminum foil, rolling and cutting to obtain the positive electrode plate.
6. The method of claim 5, wherein the step of separating the rejected lithium-rich manganese-based positive electrode sheet to obtain the active material comprising the lithium-rich manganese-based material comprises:
and immersing the scrapped lithium-rich manganese-based positive plate in deionized water until the aluminum foil is separated from the active material containing the lithium-rich manganese-based, so as to obtain the active material containing the lithium-rich manganese-based.
7. The method according to claim 5, wherein the first lithium-manganese-rich material powder is obtained by ball milling the active material containing lithium-manganese groups and drying the active material by spray drying.
8. The method according to claim 5, wherein the first lithium-rich manganese-based material powder, the mixed metal salt solution, the precipitant solution and the complexing agent solution are mixed to obtain a mixed solution, and the mixed solution is placed in a reaction kettle to perform a precipitation and chemical combination reaction, wherein the pH value of the mixed solution is kept at 10-12, the temperature of the precipitation and chemical combination reaction is 100-120 ℃, and the time is 5-10 h.
9. The method of claim 5, wherein the heat treatment is performed at a temperature of 700 ℃ to 750 ℃ for 3h to 5h in the process of mixing the composite active material precursor with a carbon source and a lithium source to obtain the composite active material.
10. An electrode assembly comprising the positive electrode sheet of any one of claims 1 to 4.
11. An energy storage device comprising the positive electrode sheet of any one of claims 1-4 or the electrode assembly of claim 10.
12. A powered device comprising the energy storage device of claim 11, the energy storage device powering the powered device.
CN202310601245.9A 2023-05-25 2023-05-25 Positive plate and preparation method thereof, electrode assembly, energy storage device and electric equipment Pending CN116404108A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116581280A (en) * 2023-07-12 2023-08-11 深圳海辰储能控制技术有限公司 Positive electrode material, preparation method thereof, positive electrode plate and lithium battery

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116581280A (en) * 2023-07-12 2023-08-11 深圳海辰储能控制技术有限公司 Positive electrode material, preparation method thereof, positive electrode plate and lithium battery
CN116581280B (en) * 2023-07-12 2023-09-12 深圳海辰储能控制技术有限公司 Positive electrode material, preparation method thereof, positive electrode plate and lithium battery

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