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CN115440931A - Lithium ion battery electrode plate and preparation method thereof - Google Patents

Lithium ion battery electrode plate and preparation method thereof Download PDF

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Publication number
CN115440931A
CN115440931A CN202211112623.9A CN202211112623A CN115440931A CN 115440931 A CN115440931 A CN 115440931A CN 202211112623 A CN202211112623 A CN 202211112623A CN 115440931 A CN115440931 A CN 115440931A
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China
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electrode plate
lithium ion
ion battery
electrode
preparation
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谭军
张成智
王飞
李峰
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Ji Hua Laboratory
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Ji Hua Laboratory
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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
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • 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
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
    • 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
    • H01M4/04—Processes of manufacture in general
    • H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
    • 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
    • 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
    • H01M4/134—Electrodes based on metals, Si or alloys
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
    • 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
    • H01M4/621—Binders
    • 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
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • 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
    • H01M2004/027—Negative electrodes

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  • General Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

The invention discloses a lithium ion battery electrode plate and a preparation method thereof, belonging to the field of lithium ion batteries. The invention mixes the film forming agent and the active substance, coats the mixture on the electrode plate, and then carries out carbonization treatment to construct the carbon-coated particle electrode plate structure without organic binder. The carbonization process is introduced into the preparation process of the electrode plate, the organic binder is carbonized at high temperature to form a carbon coating layer and chemical bonding on the electrode plate, the carbon coating layer is simultaneously used as the binder and the conductive agent, the interface stability and the electron transmission property of the electrode plate are improved, good electron and ion transmission properties can be kept under the volume change of the electrode in the charging and discharging process, the structural stability of the electrode is improved, the expansion rate is reduced, the first coulomb efficiency of the battery is improved, and the cycle stability, the rate capability and the low-temperature performance are improved. The electrode pole piece can be applied to a secondary battery cathode and has a large market potential.

Description

Lithium ion battery electrode plate and preparation method thereof
Technical Field
The invention relates to the field of lithium ion batteries, in particular to a lithium ion battery electrode plate and a preparation method thereof.
Background
The ever-increasing market for portable electronic devices and electric vehicles has had a significant impact on the technology for developing higher energy density secondary batteries.
The combination property of the battery is basically determined by the property of the battery composition material and the preparation process. Compared with materials, the pole piece preparation optimization has special advantages, and the performance of active substances is determined, especially thick pole pieces.
The pole piece design comprises optimization of a current collector, a conductive agent, a binder and the like and flexible electrode design. Wherein the current collector optimization is mainly focused on: firstly, thinning a current collector to reduce the proportion of inactive substances; secondly, a microstructure is designed on the current collector, and the linkage of active substances and the like is enhanced. The optimization of the two current collectors has the problems of high manufacturing cost, complex process and the like. The main purpose of the optimization of the conductive agent is to improve the electron and ion transmission of the pole piece, and the conductive agent with better effect at present is graphene and carbon nano tubes, but is limited by the cost and the complexity of the preparation of the pole piece. The flexible electrode can obtain excellent electrochemical performance in the button cell, and particularly shows ultrahigh energy density in the aspect of surface capacity, but the practical application of the flexible electrode is restricted by the problems that the flexible electrode is difficult to weld a tab and the like.
Compared with the first two pole piece optimization and flexible electrode design, designing a proper binder is the most promising optimization scheme. The adhesive with excellent electron and ion transmission can be used as an adhesive, a conductive agent is not required to be added into the pole piece, and the proportion of active substances in the pole piece can be increased, so that the energy density of the battery is improved. However, the production cost and the complex process of the currently reported binders are high, which restricts the large-scale application of the binders. In addition, most of the binders are organic matters, so that the electrode plate has high electrolytic swelling rate, and the active substance is easy to expand in the electrochemical process, so that the use safety is worried. Therefore, it is necessary to search a new preparation process of the electrode plate instead of using a conductive adhesive.
Disclosure of Invention
The invention mainly aims to provide a lithium ion battery electrode piece and a preparation method thereof, and aims to prepare the lithium ion battery electrode piece containing an active substance 1-carbon composite structure by a carbonization process, replace an electrode piece using a conductive adhesive, and solve the technical problems of poor stability of the electrode piece, unsatisfactory electron and ion transmission performance, high expansion rate, to-be-improved safety performance and the like
In order to achieve the above purpose, the present invention provides a lithium ion battery electrode plate, which includes an active material, a current collector, and a carbon coating layer coated on the active material and the current collector, and does not contain an organic substance, wherein the active material is a negative electrode material, and the negative electrode material includes at least one of graphite, hard carbon, silicon monoxide, and silicon.
Optionally, the compacted density of the electrode pole piece of the lithium ion battery is 1.0g c1 -3 ≤ρ≤5.0g c1 -3 The density of the single-sided surface is 1 to 200 g c1 -2 The thickness is 20-1000 mu 1, the specific surface area is increased by less than or equal to 100 2 g -1 。
In addition, in order to achieve the above object, the present invention further provides a preparation method of an electrode plate of a lithium ion battery, the preparation method comprising the following steps:
s10, mixing an active substance and a film-forming agent, uniformly stirring to obtain a viscous mixture, coating the viscous mixture on the surface of a current collector, and drying to obtain an initial negative plate;
s20, heating the initial negative plate to prepare a lithium ion battery electrode plate;
wherein the active material is a negative electrode material including at least one of graphite, hard carbon, silica, and silicon.
Optionally, the weight ratio of the active substance to the film forming agent is 0.5.
Optionally, in the step of mixing and uniformly stirring the active substance and the film forming agent, the stirring temperature is 10-200 ℃, and the stirring time is 1-24 hours.
Optionally, the current collector is at least one of a copper foil, a steel foil, and a titanium foil.
Further optionally, the current collector is a copper foil.
Optionally, in the step of performing heat treatment on the initial negative electrode sheet, the heat treatment on the initial negative electrode sheet is performed in an inert gas atmosphere, wherein the inert gas atmosphere is at least one of nitrogen, argon and argon-hydrogen mixed gas.
Optionally, the temperature of the heating treatment is 250-1500 ℃, the heating rate is 1-10 ℃ 1111, and the heat preservation time is 0-24 h.
Optionally, performing secondary carbon coating on the prepared lithium ion battery electrode piece.
Optionally, the lithium ion battery electrode piece is subjected to secondary carbon coating by a vapor deposition method.
Optionally, the temperature of the vapor deposition method is 600-1200 ℃, and the holding time is 0.5-24 h.
Optionally, the viscous mixture has a viscosity of 1000 to 8000 pa · s.
Optionally, the active material particles D50 are between 1 and 30 μ 1.
Optionally, the viscous mixture has a viscosity of 1000 to 8000 pa · s.
Optionally, the film forming agent comprises one or more of starch, starch derivatives, carboxymethylcellulose, ethylcellulose, hydroxyethylcellulose, polyacrylamide, polyethyleneimine, polymaleic anhydride, polyquaternary ammonium salts, hydrolyzed polyacrylamide, natural vegetable gums, polyethylene oxide, ionic water-soluble epoxy resins, ionic maleated polybutadiene resins, cationic water-soluble polyvinyl chloride resins, aqueous asphalt emulsions, aqueous epoxy resins, aqueous polyacrylates, sodium carboxymethylcellulose, sodium carboxymethyl starch, polyvinyl alcohol, sodium polystyrene sulfonate, polydopamine, polyethylene glycol, aqueous polyurethanes, polyacrylic acid, guar gum, chitosan, gelatin, sodium alginate, polyvinylpyrrolidone, xanthan gum, calcium alginate, gellan gum, cyclodextrin, karaya gum, gum arabic, and derivatives thereof.
The invention can realize the following beneficial effects:
the invention provides an electrode plate of a lithium ion battery, which comprises an active substance, a carbon coating layer and a current collector. The carbon coating layer has the function of a conductive agent, and also has the functions of a bonding effect with an active substance and a current collector under a high-temperature environment and a role of a binder, so that strong interface binding force is formed between the carbon coating layer and the active substance, the expansion of the active substance in the electrochemical process is limited, the volume expansion can be effectively relieved, the electrode structure is prevented from being damaged, and the expansion rate of the electrode plate is reduced. In addition, because the electrode pole piece does not contain organic matters, the swelling ratio of the electrolyte is almost zero, while the electrolytic swelling ratio of the traditional cathode pole piece is as high as 50%, and the electrochemical performance of the use safety can be improved due to the low electrode swelling ratio and the low electrolyte swelling ratio.
The lithium ion battery electrode pole piece is applied to the battery, so that the battery has the advantages of high low-temperature performance and energy density, high first coulombic efficiency and good cycle stability. In addition, because the carbon coating layer has excellent electron and ion transmission, an ultra-thick pole piece with the thickness more than 300 mu 1 can be designed, and the proportion of inactive components is further reduced, so that the energy density of the battery can be improved, and the cost is reduced.
The electrode preparation method disclosed by the invention is simple and feasible, has no pollution, is safe and reliable, has low cost, more general applicability and higher production efficiency, can realize industrial batch production, does not add a conductive agent, reduces the process complexity and the manufacturing cost, reduces the proportion of low-1 inactive substances in the electrode, and is easy to prepare a high-compaction pole piece.
Drawings
In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present invention, the drawings used in the description of the embodiments or prior art are briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
Fig. 1 is a process flow chart of a method for preparing an electrode plate of a lithium ion battery in embodiments 1 to 4 of the present invention.
Fig. 2 is a process flow chart of a method for manufacturing an electrode plate of a lithium ion battery in embodiment 5 of the present invention.
Fig. 3 is a surface scanning electron microscope image of the electrode plate of the lithium ion battery in embodiment 1 of the present invention.
Fig. 4 is a cross-sectional scanning electron microscope backscattered electron image of a lithium ion battery electrode piece cut by a focused ion beam in example 1 of the present invention.
Fig. 5 is a first charging and discharging curve of the electrode plate of the lithium ion battery in example 1 of the present invention at a current density of 0.033C (1c =3579 1A1g).
Fig. 6 is a graph of cycle performance of the electrode sheet of the lithium ion battery in example 1 of the present invention at a current density of 0.033C (1c =3579 1A1g).
The implementation, functional features and advantages of the present invention will be further described with reference to the accompanying drawings.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Descriptions such as "first," "second," etc. in this disclosure are for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between the embodiments may be combined with each other, but must be based on the realization of the technical solutions by a person skilled in the art, and when the technical solutions are contradictory to each other or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
The invention provides an electrode plate of a lithium ion battery, which comprises an active substance, a current collector and a carbon coating layer coated on the active substance and the current collector, wherein the carbon coating layer does not contain organic matters, the active substance is a negative electrode material, the negative electrode material comprises at least one of graphite, hard carbon, silicon monoxide and silicon, and the carbon coating layer can be simultaneously used as a binder and a conductive agent of the electrode plate.
The compaction density of the electrode plate of the lithium ion battery is 1.0gc1 -3 ≤ρ≤5.0gc1 -3 The single-sided surface density is 1 to 2001gc1 -2 The thickness is 20-1000 mu 1, the specific surface area is not more than 1001 2 g -1 。
The invention also provides a preparation method of the electrode plate of the lithium ion battery, and in one embodiment, referring to fig. 1, the preparation method comprises the following steps:
and S10, mixing the active substance and the film-forming agent, uniformly stirring to obtain a viscous mixture, coating the viscous mixture on the surface of the current collector, and drying to obtain the initial negative plate.
The film forming agent includes a water soluble polymer, but is not limited to a water soluble polymer, and preferably the film forming agent includes one or more of starch, starch derivatives, carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, polyacrylamide, polyethyleneimine, polymaleic anhydride, polyquaternary ammonium salts, hydrolyzed polyacrylamide, natural vegetable gums, polyethylene oxide, ionic water soluble epoxy resins, ionic maleated polybutadiene resins, cationic water soluble polyvinyl chloride resins, aqueous asphalt emulsions, aqueous epoxy resins, aqueous polyacrylates, sodium carboxymethyl cellulose, sodium carboxymethyl starch, polyvinyl alcohol, sodium polystyrene sulfonate, polydopamine, polyethylene glycol, aqueous polyurethanes, polyacrylic acid, guar gum, chitosan, gelatin, sodium alginate, polyvinyl pyrrolidone, xanthan gum, calcium alginate, gellan gum, cyclodextrin, karaya gum, gum arabic, and derivatives thereof.
The invention does not limit the weight ratio of the active substance to the film forming agent, preferably, the weight ratio of the active substance to the film forming agent is 0.5; in some embodiments, the active material has a D50 of 1 to 30 μ 1 and a specific surface area of 1 to 101 2 g -1 (ii) a In some embodiments, the temperature for mixing and uniformly stirring the active substance and the film forming agent is preferably 10-200 ℃, and the stirring time is preferably 1-24 h. Under the preferred conditions described above, the active substance and the film-forming agent may be mixed more homogeneously and may also promote subsequent carbonization reactions.
In this embodiment, the film forming agent may be understood as a binder, and when the film forming agent is a water-soluble polymer, the water-soluble polymer may be dissolved in a mixed solution of deionized water and alcohol, and then the active material is added, so that the problem that the electrochemical performance of the carbon coating layer is affected due to uneven dispersion of the active material and the film forming agent can be avoided.
The viscosity of the viscous mixture is preferably 1000 to 8000 pa · s. Within the viscosity of 1000-80001 Pa · s, the adhesive force of the viscous mixture on the current collector can be enhanced, and the viscous mixture is prevented from falling off due to insufficient viscosity in the high-temperature carbonization process, so that the effect of the carbon coating layer as an adhesive in a finished product is prevented from being influenced.
The invention is not limited to the kind of the current collector, and the current collector is preferably at least one of a copper foil, a steel foil and a titanium foil, and further, the current collector is a copper foil.
And S20, heating the initial negative pole piece to prepare the lithium ion battery electrode piece.
Specifically, the heating treatment is performed in an inert gas atmosphere, which is at least one of nitrogen, argon, and argon-hydrogen mixed gas.
The temperature of the heating treatment in the step is preferably 250-1500 ℃, the heating rate is preferably 1-10 ℃ 1111, and the heat preservation time is 0-24 h. The carbonization temperature is kept to be slowly increased, so that the phenomenon that the viscous mixture is heated unevenly due to the instant temperature rise, the carbon coating layer cracks, and active material particles are pulverized can be prevented. The heat retention time is calculated from the start of temperature rise to a stable temperature. The holding time of 0 to 24 hours can be understood as follows: the heat preservation treatment can be carried out, or the heat preservation treatment can be carried out without carrying out the heat preservation treatment, so that the electrochemical stability of the carbon coating layer can be further improved.
According to the invention, a heat treatment process is introduced into the preparation process of the pole piece, an active substance 1-carbon composite structure is formed on the pole piece, an integrated electrode is constructed, and the performances of the electrode piece, such as electron and ion transmission, can be greatly improved, so that the negative electrode piece with high initial coulombic efficiency and long-cycle stability is obtained.
The active substance 1 carbon composite structure of the lithium ion battery electrode plate is different from the carbon coating of a single-particle active substance, but a composite material which takes the active substance as a reinforcing phase and takes a carbon coating layer as a matrix is formed on a current collector, and strong constraint force exists between particles, namely, stronger chemical bonding action exists between the carbon coating layer and active substance particles and between the carbon coating layer and the current collector, so that the carbon coating layer can be simultaneously used as a binder and a conductive agent of the electrode plate, can adapt to the volume change of the active substance, controls the expansion degree of the active substance in the electrochemical process, can effectively prevent the carbon coating layer from cracking, pulverizes the active substance particles, ensures that the environment of a conductive ring is not damaged, and further reduces the expansion rate of the electrode plate. In addition, because the electrode plate does not contain organic matters, the swelling rate of the electrolyte is almost zero, and the electrolytic swelling rate of the traditional negative electrode plate is as high as 50%. The low electrode expansion rate and the low electrolyte swelling rate can improve the use safety and the electrochemical performance.
In addition, because the electrode plate does not contain organic matters and has extremely low water content, the electrode plate has the characteristics of high heat conduction, nonflammability and high safety performance.
Wherein, the current collector and the carbon coating layer form bonding effect under high-temperature environment, and the bonding effect comprises but is not limited to at least one of C-O-Cu, C-O-Fe and C-O-T1 bond; the active material forms bonding with the carbon coating layer under a high-temperature environment, and the bonding comprises but is not limited to one or more of C-O-C, C-O-S1 and C-S1.
In another embodiment, referring to fig. 2, the preparation method further includes performing secondary carbon coating on the lithium ion battery electrode sheet.
Specifically, under a protective atmosphere, introducing carbon-containing process gas to perform vapor deposition of carbon element, and performing secondary carbon coating on the electrode plate, wherein the protective atmosphere is at least one of nitrogen, argon and argon-hydrogen mixed gas. The carbon-containing process gas is one of C1-4 alkane, C2-4 alkene and C2-4 alkyne. And the mechanical stability and the electrochemical stability of the electrode plate can be further improved through secondary carbon coating.
The compacted density of the electrode plate of the lithium ion battery prepared by the method is 1.0gc1 -3 ≤ρ≤5.0gc1 -3 The single-sided surface density is 1-2001g c1 -2 The thickness is 20-1000 mu 1, the specific surface area is not more than 1001 2 g -1 。
The technical solutions of the present invention are further described in detail with reference to the following specific examples, which should be understood as merely illustrative and not limitative.
Example 1
Referring to fig. 1, the preparation method of the electrode plate of the lithium ion battery comprises the following steps:
s10, weighing 200 g of soluble starch, dissolving the soluble starch in deionized water, stirring for 0.5h under the condition of 80 ℃ water bath, then adding 200 g of silicon powder with the particle size of 5 mu 1, and stirring for 1h at 10 ℃ to obtain a viscous mixture. The viscous mixture was uniformly coated on a 10 μ 1 steel foil and dried to obtain the initial pole piece.
S20, after the initial pole piece punching sheet of the S10 is manufactured into a button cell pole piece with the diameter of 1211, moving the button cell pole piece to a tube furnace for heat treatment, wherein the carbonization procedure is as follows: heating to 1500 ℃ at 10 ℃ of 1111 ℃ and then preserving heat for 0.5h to obtain the electrode plate of the lithium ion battery.
In this embodiment, the lithium ion battery electrode plate is a micron silicon-based lithium ion battery electrode plate, and can be directly used as a working electrode plate for assembling a button cell, and the active material includes silicon and carbon.
The micrometer silicon-based lithium ion battery electrode piece obtained in example 1 is characterized by a scanning electron microscope, and the result is shown in fig. 3: a layer of starch carbon is uniformly deposited near the micron silicon particles on the electrode pole piece of the micron silicon-based lithium ion battery.
Cutting the electrode plate of the micron silicon-based lithium ion battery by using a focused ion beam, and characterizing the exposed cross section of the cut electrode plate by using a scanning electron microscope to obtain a back scattering electron image of the scanning electron microscope, as shown in fig. 4: the electrodes form a good electron and ion transport network after carbonization.
Example 2
Referring to fig. 1, the preparation method of the electrode plate of the lithium ion battery comprises the following steps:
s10, weighing 1901g of sodium carboxymethylcellulose, dissolving the sodium carboxymethylcellulose in a mixed solution of deionized water and alcohol, stirring for 0.5h, then adding 10 1g of silicon powder with the particle size of 3011, stirring for 6h at 25 ℃ to obtain a viscous mixture, uniformly coating the viscous mixture on a copper foil with the particle size of 10 mu 1, and drying to obtain the initial pole piece.
S20, after the initial pole piece punching sheet of the S10 is made into a button cell pole piece with the diameter of 1211, moving the button cell pole piece to a tubular furnace for heating carbonization treatment, wherein the carbonization treatment procedure is as follows: and heating to 500 ℃ at 1 ℃ and then preserving heat for 2 hours to obtain the electrode plate of the lithium ion battery.
In this embodiment, the lithium ion battery electrode plate is a nano silicon-based lithium ion battery electrode plate, and can be directly used as a working electrode plate for assembling a button cell, and the active material includes silicon and carbon.
Example 3
In this embodiment, referring to fig. 1, the method for manufacturing an electrode plate of a lithium ion battery includes the following steps:
s10, weighing 2001g of ethyl cellulose, dissolving the ethyl cellulose in a mixed solution of deionized water and alcohol, stirring for 0.5h, then adding 6001g of graphite with the particle size of 12 mu 1, stirring for 12h at 200 ℃ to obtain a viscous mixture, uniformly coating the viscous mixture on 10 mu 1 of titanium foil, and drying to obtain the initial pole piece.
S20, after the initial pole piece punching sheet of the S10 is made into a button cell pole piece with the diameter of 1211, moving the button cell pole piece to a tubular furnace for heating carbonization treatment, wherein the carbonization treatment procedure is as follows: and heating to 250 ℃ at 5 ℃ 1111, and then preserving heat for 24 hours to obtain the electrode plate of the lithium ion battery.
In this embodiment, the lithium ion battery electrode plate is an integrated graphite-based lithium ion battery electrode plate, and can be directly used as a working electrode plate for assembling a button cell, and the active material includes silicon and carbon.
Example 4
In this embodiment, referring to fig. 1, the method for manufacturing an electrode plate of a lithium ion battery includes the following steps:
s10, weighing 501g of sodium carboxymethylcellulose, putting the sodium carboxymethylcellulose into a weighing bottle, dissolving the sodium carboxymethylcellulose into a mixed solution of deionized water and alcohol, stirring for 0.5h, then adding 4501g of graphite with the particle size of 12 mu 1 and 5001g of micron silicon with the particle size of 5 mu 1, stirring for 15h at 30 ℃ to obtain a viscous mixture, uniformly coating the viscous mixture on 10 mu 1 of copper foil, and drying to obtain the initial pole piece.
S20, after the initial pole piece punching sheet of the S10 is manufactured into a button cell pole piece with the diameter of 1211, moving the button cell pole piece to a tube furnace for heating carbonization treatment, wherein the carbonization treatment procedure is as follows: heating to 500 ℃ at 1 ℃ to obtain the electrode plate of the lithium ion battery.
In this embodiment, the lithium ion battery electrode plate is a silicon 1 graphite-based lithium ion battery electrode plate, and can be directly used as a working electrode plate for assembling a button cell, and the active material includes silicon, graphite, and carbon.
Example 5
Referring to fig. 2, the preparation method of this example is substantially the same as that of example 1, except that the lithium ion battery electrode sheet obtained in step S20 is subjected to secondary carbon coating by a vapor deposition method: and introducing C1-4 alkane and C2-4 alkene in the protective atmosphere of nitrogen, and depositing carbon element for 24 hours at 1200 ℃ to obtain the secondary carbon-coated electrode plate of the lithium ion battery.
Comparative example 1
Comparative example 1 is the same as the preparation method of example 1 except that the heating treatment in the S20 step is not performed.
Performance testing
The button cell was assembled by using the electrode sheets obtained in examples 1 to 5 and comparative example 1 as one of the electrodes and a lithium metal sheet as the counter electrode, respectively. Wherein, all allocate electrolyte through following mode: 1.0M lithium hexafluorophosphate (L1 PF 6) was dissolved in a solvent at a volume ratio of 1:1 Ethylene Carbonate (EC) and diethyl carbonate (DEC), 7.5% fluoroethylene carbonate (FEC) and 0.5% Vinylene Carbonate (VC) were added as an electrolyte solution.
1. The initial circulating current density was set to 0.033C (1c = 35791a1g), all the button cells were charged and discharged, and the initial charging specific capacity, and the specific capacity and the capacity retention rate after 50 cycles when the circulating current density was 0.33C of the electrode sheet were measured. The results are shown in Table 1.
TABLE 1 comparison of electrochemical Properties of electrode sheets obtained in examples 1 to 5 and comparative example 1
Figure BDA0003842932060000091
Figure BDA0003842932060000101
2. The constant current ratios of the electrode sheets of examples 1 to 5 and comparative example 1 were measured under the conditions that the first cycle current density was 0.033c,1c =3721a1g and the rate retention was 0.1C, and the results are shown in table 2.
TABLE 2 comparison of electrochemical Properties of electrode sheets obtained in examples 1 to 5 with that of comparative example 1
Figure BDA0003842932060000102
As can be seen from fig. 5, fig. 6 and table 1, the first discharge specific capacity of the electrode plate of the micron silicon-based lithium ion battery of example 1 is 3366.71ah1g, the charge specific capacity is 3084.01ah1g, the first coulombic efficiency is as high as 91.6%, and the capacity still maintains the ultra-high capacity of 2002.51ah1g after the current density is 0.33C and 50 cycles.
In addition, the electrode plates of the embodiments 2 to 5 have higher first coulombic efficiency and first charging specific capacity, and have higher specific capacity and capacity retention rate after 50 times of circulation.
The electrode piece of comparative example 1 did not pass through the heating process, its electrochemical performance was poor, and the capacity retention rate after 50 cycles was almost zero.
As can be seen from Table 2, the pole piece prepared by the method has excellent rate capability and better electron ion transport capacity.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims (10)

1. A preparation method of an electrode plate of a lithium ion battery is characterized by comprising the following steps:
mixing an active substance and a film-forming agent, uniformly stirring to obtain an adhesive mixture, coating the adhesive mixture on the surface of a current collector, and drying to obtain an initial negative plate;
heating the initial negative plate to prepare a lithium ion battery electrode plate;
wherein the active material is a negative electrode material including at least one of graphite, hard carbon, silica and silicon.
2. The preparation method of the electrode piece of the lithium ion battery of claim 1, wherein the weight ratio of the active material to the film forming agent is 0.5.
3. The preparation method of the electrode piece of the lithium ion battery of claim 1, wherein in the step of mixing and uniformly stirring the active substance and the film-forming agent, the stirring temperature is 10-200 ℃, and the stirring time is 1-24 hours.
4. The method for preparing the electrode plate of the lithium ion battery according to claim 1, wherein the current collector is at least one of copper foil, steel foil and titanium foil.
5. The method for preparing the electrode plate of the lithium ion battery according to claim 1, wherein in the step of performing the heating treatment on the initial negative electrode plate, the heating treatment on the initial negative electrode plate is performed in an inert gas atmosphere, and the inert gas atmosphere is at least one of nitrogen, argon and argon-hydrogen mixed gas.
6. The preparation method of the electrode plate of the lithium ion battery of claim 1, wherein the temperature of the heating treatment is 250-1500 ℃, the heating rate is 1-10 ℃ 1111, and the heat preservation time is 0-24 h.
7. The method for preparing the electrode plate of the lithium ion battery according to claim 1, wherein the prepared electrode plate of the lithium ion battery is subjected to secondary carbon coating.
8. The method for preparing the electrode plate of the lithium ion battery according to claim 7, wherein the electrode plate of the lithium ion battery is subjected to secondary carbon coating by a vapor deposition method.
9. The method for preparing an electrode plate of a lithium ion battery according to claim 1, wherein the film forming agent comprises one or more of starch, starch derivatives, carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, polyacrylamide, polyethyleneimine, polymaleic anhydride, polyquaternary ammonium salts, hydrolyzed polyacrylamide, natural vegetable gums, polyethylene oxide, ionic water-soluble epoxy resins, ionic maleated polybutadiene resins, cationic water-soluble polyvinyl chloride resins, aqueous pitch emulsions, aqueous epoxy resins, aqueous polyacrylates, sodium carboxymethyl cellulose, sodium carboxymethyl starch, polyvinyl alcohol, sodium polystyrene sulfonate, polydopamine, polyethylene glycol, aqueous polyurethanes, polyacrylic acid, guar gum, chitosan, gelatin, sodium alginate, polyvinyl pyrrolidone, xanthan gum, calcium alginate, gellan gum, cyclodextrin, karaya gum, gum arabic gum, and derivatives thereof.
10. The lithium ion battery electrode piece prepared by the preparation method of any one of claims 1 to 9, characterized in that the lithium ion battery electrode piece comprises an active material, a current collector and a carbon coating layer coated on the active material and the current collector, and contains no organic matter, the active material is a negative electrode material, and the negative electrode material comprises at least one of graphite, hard carbon, silicon monoxide and silicon.
CN202211112623.9A 2022-09-13 2022-09-13 Lithium ion battery electrode plate and preparation method thereof Pending CN115440931A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115663195A (en) * 2022-12-22 2023-01-31 博路天成新能源科技有限公司 Silicon-based negative plate and preparation method thereof, lithium ion battery and electronic equipment
CN116168959A (en) * 2023-03-28 2023-05-26 天津普兰能源科技有限公司 Low-gas-yield dry electrode plate, super capacitor and preparation method
CN116936750A (en) * 2023-09-18 2023-10-24 季华实验室 Lithium ion battery negative electrode plate, preparation method thereof, negative electrode plate slurry and lithium ion battery
WO2024179533A1 (en) * 2023-03-01 2024-09-06 郑州大学 Aqueous binder and use thereof in hard carbon negative electrode of sodium-ion battery

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115663195A (en) * 2022-12-22 2023-01-31 博路天成新能源科技有限公司 Silicon-based negative plate and preparation method thereof, lithium ion battery and electronic equipment
WO2024179533A1 (en) * 2023-03-01 2024-09-06 郑州大学 Aqueous binder and use thereof in hard carbon negative electrode of sodium-ion battery
CN116168959A (en) * 2023-03-28 2023-05-26 天津普兰能源科技有限公司 Low-gas-yield dry electrode plate, super capacitor and preparation method
CN116168959B (en) * 2023-03-28 2023-09-12 天津普兰能源科技有限公司 Low-gas-yield dry electrode plate, super capacitor and preparation method
CN116936750A (en) * 2023-09-18 2023-10-24 季华实验室 Lithium ion battery negative electrode plate, preparation method thereof, negative electrode plate slurry and lithium ion battery

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