CN111883741A - Negative plate and manufacturing method thereof - Google Patents

Negative plate and manufacturing method thereof Download PDF

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Publication number
CN111883741A
CN111883741A CN202010767885.3A CN202010767885A CN111883741A CN 111883741 A CN111883741 A CN 111883741A CN 202010767885 A CN202010767885 A CN 202010767885A CN 111883741 A CN111883741 A CN 111883741A
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negative electrode
graphene oxide
manufacturing
mass ratio
slurry
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张静娴
李根雨
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Hunan Xinminya New Energy Technology Co Ltd
Sichuan Xinminya Battery Technology Co Ltd
Suzhou Lingwei New Energy Technology Co Ltd
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Hunan Xinminya New Energy Technology Co Ltd
Sichuan Xinminya Battery Technology Co Ltd
Suzhou Lingwei New Energy Technology Co Ltd
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Priority to CN202010767885.3A priority Critical patent/CN111883741A/en
Publication of CN111883741A publication Critical patent/CN111883741A/en
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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
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • 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
    • 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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  • Electrochemistry (AREA)
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Abstract

The application provides a negative plate and a manufacturing method thereof, and the method comprises the following steps: preparing a graphene oxide dispersion liquid; mixing the graphene oxide dispersion liquid with a binder to form a glue solution; mixing the glue solution with silica and a conductive agent to form negative electrode slurry; and coating the negative electrode slurry on a negative electrode current collector to form a negative electrode sheet. According to the negative plate and the manufacturing method thereof, the negative electrode is manufactured by mixing the graphene oxide serving as the functional additive with the silica, the manufacturing method is simple and convenient, the cost is low, and the manufactured negative plate is excellent in performance and has a large commercial application prospect.

Description

Negative plate and manufacturing method thereof
Technical Field
The application relates to the technical field of lithium batteries, in particular to a negative plate and a manufacturing method thereof.
Background
The graphite negative electrode is a negative electrode material which is commercialized at the earliest and is still used up to now, and in order to further increase the energy density of the lithium ion battery, a negative electrode material with higher capacity needs to be developed. Silicon has ultrahigh theoretical gram capacity (4200mAh/g), is abundant in silicon resource and low in price, and is the next-generation anode material which is most hopeful to be commercialized in a large scale. However, the silicon-based negative electrode has more obvious defects, such as much lower conductivity than graphite, huge volume change (300-400%) during charge and discharge, powdering during the cycle process, and the like. The currently common and effective improvement method is to use carbon material to coat/compound to form the silicon-carbon composite negative electrode material. The carbon material is coated/compounded, so that the volume change of the silicon-based negative electrode in the charging and discharging process can be effectively limited, the conductivity and the stability of the silicon-based negative electrode are improved, side reactions are reduced, powdering is inhibited, and the coulomb efficiency and the cycle life of the battery are improved while the energy density of the lithium ion battery is improved.
Carbon-coated/composite materials commonly used for silicon-based negative electrode materials which are commercialized at present mainly comprise amorphous carbon, graphite, carbon nanotubes, carbon microspheres, graphene and the like. After the nano materials such as the carbon nano tube, the graphene and the like and the silicon-based negative electrode material are coated/compounded, the composite material shows more outstanding performance.
However, although the efficiency, rate and cycle performance of the silicon-based composite negative electrode that has been commercialized at present are improved for the first time, the carbon material coated/compounded on the silicon negative electrode affects the original gram capacity of the silicon negative electrode and increases the production cost. Therefore, it is necessary to provide a new composite method and a composite material so that the silicon-based composite negative electrode has higher cost performance than the graphite negative electrode.
Disclosure of Invention
The application provides a negative plate and a manufacturing method thereof, which are simple and convenient, low in cost, excellent in performance of the manufactured negative plate and have a wide commercial application prospect.
One aspect of the present application provides a negative electrode sheet, including: the negative electrode comprises a negative electrode current collector and negative electrode slurry coated on the surface of the negative electrode current collector, wherein the negative electrode slurry comprises silica and graphene oxide.
In some embodiments of the present application, the number of graphene oxide sheets is 1 to 3.
In some embodiments of the present application, the graphene oxide flakes are 0.1 to 5 microns in size.
In some embodiments of the present application, the negative electrode slurry further includes a binder and a conductive agent, where the mass ratio of the silicon to the oxygen is 85% to 98%, the mass ratio of the binder is 1.5% to 11%, the mass ratio of the conductive agent is 1% to 5%, and the mass ratio of the graphene oxide is 0.01% to 0.5%, based on the solute mass of the negative electrode slurry.
Another aspect of the present application provides a method for manufacturing a negative electrode sheet, including: preparing a graphene oxide dispersion liquid; mixing the graphene oxide dispersion liquid with a binder to form a glue solution; mixing the glue solution with silica and a conductive agent to form negative electrode slurry; and coating the negative electrode slurry on a negative electrode current collector to form a negative electrode sheet.
In some embodiments of the present application, a method of preparing a graphene oxide dispersion includes: and carrying out ultrasonic treatment on the graphene oxide slurry in deionized water for 15 to 60 minutes to obtain a uniformly dispersed graphene oxide dispersion liquid.
In some embodiments of the present application, the concentration of the graphene oxide dispersion is 0.01g/L to 0.3 g/L.
In some embodiments of the present application, the number of graphene oxide sheets in the graphene oxide dispersion is 1 to 3.
In some embodiments of the present application, the graphene oxide flakes in the graphene oxide dispersion have a size of 0.1 to 5 microns.
In some embodiments of the present application, based on the mass of the solute of the negative electrode slurry, the mass ratio of the silicon oxygen is 85% to 98%, the mass ratio of the binder is 1.5% to 11%, the mass ratio of the conductive agent is 1% to 5%, and the mass ratio of the graphene oxide is 0.01% to 0.5%.
According to the negative plate and the manufacturing method thereof, the negative electrode is manufactured by mixing the graphene oxide serving as the functional additive with the silica, the manufacturing method is simple and convenient, the cost is low, and the manufactured negative plate is excellent in performance and has a large commercial application prospect.
Drawings
The following drawings describe in detail exemplary embodiments disclosed in the present application. Wherein like reference numerals represent similar structures throughout the several views of the drawings. Those of ordinary skill in the art will understand that the present embodiments are non-limiting, exemplary embodiments and that the accompanying drawings are for illustrative and descriptive purposes only and are not intended to limit the scope of the present application, as other embodiments may equally fulfill the inventive intent of the present application. It should be understood that the drawings are not to scale. Wherein:
fig. 1 is a flowchart of a method for manufacturing a negative electrode sheet according to an embodiment of the present application;
fig. 2 is a graph illustrating the first discharge performance of a battery fabricated using a negative electrode sheet according to some embodiments of the present disclosure;
fig. 3 is a test chart of charge and discharge cycle performance of batteries manufactured using the negative electrode sheet in some examples of the present application.
Detailed Description
The following description is presented to enable any person skilled in the art to make and use the present disclosure, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present application. Thus, the present application is not limited to the embodiments shown, but is to be accorded the widest scope consistent with the claims.
The technical solution of the present invention will be described in detail below with reference to the embodiments and the accompanying drawings.
An embodiment of the present application provides a negative electrode sheet, including: the negative electrode comprises a negative electrode current collector and negative electrode slurry coated on the surface of the negative electrode current collector, wherein the negative electrode slurry comprises silica and graphene oxide.
The silicon-based composite negative electrode that has been commercialized at present uses a carbon material to coat/compound the silicon negative electrode, which greatly affects the original gram capacity of the silicon negative electrode and causes an increase in production cost. In the negative plate, the graphene oxide is used as a functional additive to be mixed with silica to prepare the negative electrode, the preparation method is simple and convenient, the cost is low, and the prepared negative plate has excellent performance and has a large commercial application prospect.
The negative electrode sheet in the embodiment of the application, (1) the graphene oxide is mixed into the negative electrode slurry in the form of aqueous dispersion liquid, and other subsequent treatment processes including reduction are not needed, so that the production process is greatly simplified, and the materials and the production cost are saved; (2) the graphene oxide has good adhesion, can improve the peeling strength of a pole piece, is beneficial to inhibiting the peeling of an electrode in a circulating process, reduces side reactions, improves the first efficiency of a battery and prolongs the service life of the battery; (3) the graphene oxide has good adhesion, and the usage amount of an adhesive in the preparation of the negative electrode can be greatly reduced, so that the content of active substances in a pole piece is increased, and the capacity and the energy density of a battery are increased; (4) the graphene oxide is subjected to electrochemical reduction in the first charging process of the battery, so that the conductivity of the graphene oxide is improved, the impedance of a negative electrode is reduced, and the cycling stability of the battery is improved; (5) the flexible structure of the graphene oxide is beneficial to buffering the volume change of the silicon-oxygen cathode material in the charging and discharging processes, the effective contact of the silicon-oxygen cathode and the conductive carbon black particles is ensured, and the cycle life of the battery is prolonged; (6) the preparation process of the negative plate is simple, the process conditions are easy to control and realize, and the method has a great commercial application prospect.
In some embodiments of the present application, the negative current collector is a foil. In some embodiments of the present application, the foil is made of a material such as metallic copper or metallic aluminum.
In some embodiments of the present application, the silicon oxygen is SiOx, wherein 0 < x < 2. Silicon has ultrahigh theoretical gram capacity (4200mAh/g), is rich in silicon resource and low in price, and is used as a main component of a negative electrode material.
In some embodiments of the present application, the number of graphene oxide sheets is 1 to 3. Graphene oxide is generally obtained by oxidizing graphite with strong acid, and the graphene oxide still maintains the layered structure of the graphite after oxidation treatment. The number of layers of the graphene oxide sheets cannot be too large, otherwise, materials are wasted; the number of layers of the graphene oxide sheet cannot be too small, otherwise the silicon cannot be coated well.
In some embodiments of the present application, the graphene oxide flakes are 0.1 to 5 microns in size. The graphene oxide flakes cannot be too large or too small in size, otherwise the silicon is not coated well. It should be noted that the dimensions include a diameter, a length, a width, and the like, and in practice, the shape of the graphene oxide sheet may not be a regular pattern, for example, not a regular circle or rectangle, and it should be understood that the dimensions defined by the diameter, the length, and the width described in the present application are to determine the dimensions by considering the graphene sheet as a circle or a rectangle approximately. For example, some graphene oxide flakes may tend to be round, and some graphene oxide flakes may tend to be rectangular.
In some embodiments of the present application, the negative electrode slurry further includes a binder and a conductive agent, where the mass ratio of the silicon to the oxygen is 85% to 98%, the mass ratio of the binder is 1.5% to 11%, the mass ratio of the conductive agent is 1% to 5%, and the mass ratio of the graphene oxide is 0.01% to 0.5%, based on the solute mass of the negative electrode slurry. The graphene oxide has good adhesion, so that the use amount of the adhesive can be greatly reduced, the content of active substances in the pole piece is increased, and the capacity and the energy density of the battery are increased. The negative electrode slurry further comprises deionized water as a solvent, and for convenience of explanation, the mass ratio of each component in the negative electrode slurry is defined, and only the total mass of the solute is used as a reference of the mass ratio.
In some embodiments of the present application, the binder comprises sodium carboxymethylcellulose (CMC), styrene butadiene rubber, PAA (polyacrylic acid), PVA (polyvinyl alcohol), PAN (polyacrylonitrile), ALG (sodium alginate), CTS (chitosan), and the like. The binder is used for enhancing the binding strength of other components in the negative electrode slurry and improving the good adhesion of the negative electrode slurry and an adhesion matrix.
In some embodiments of the present application, the conductive agent includes conductive carbon black, conductive graphite, Carbon Nanotubes (CNTs), carbon nanofibers (VGCF), and the like. The conductive agent is used for ensuring that the negative electrode has good charge and discharge performance, and can play a role in collecting micro-current between the negative electrode active substances and the negative electrode current collector so as to reduce the contact resistance of the negative electrode, accelerate the movement rate of electrons and effectively improve the charge and discharge efficiency of the negative electrode.
In some embodiments of the present application, the negative electrode paste includes silicon oxide, polyacrylic acid, sodium carboxymethyl cellulose, conductive carbon black, and graphene oxide. By taking the mass of the solute of the negative electrode slurry as a reference, the mass proportion of the silica is 85-98%, the mass proportion of the polyacrylic acid is 1-8%, the mass proportion of the sodium carboxymethyl cellulose is 0.5-3%, the mass proportion of the conductive carbon black is 1-5%, and the mass proportion of the graphene oxide is 0.01-0.5%.
According to the negative plate, the graphene oxide is added into the conventional silicon-oxygen negative material as the functional additive, the manufacturing method is simple and convenient, the cost is low, the manufactured negative plate is excellent in performance, and the negative plate has a large commercial application prospect.
Embodiments of the present application also provide a method for manufacturing a negative electrode sheet, and with reference to fig. 1, the method includes:
step S110: preparing a graphene oxide dispersion liquid;
step S120: mixing the graphene oxide dispersion liquid with a binder to form a glue solution;
step S130: mixing the glue solution with silica and a conductive agent to form negative electrode slurry;
step S140: and coating the negative electrode slurry on a negative electrode current collector to form a negative electrode sheet.
According to the manufacturing method of the negative plate, the negative electrode is manufactured by mixing the graphene oxide serving as the functional additive with the silica, the manufacturing method is simple and convenient, the cost is low, and the manufactured negative plate is excellent in performance and has a large commercial application prospect.
In the preparation method of the negative electrode sheet in the embodiment of the application, (1) the graphene oxide is mixed into the negative electrode slurry in the form of the aqueous dispersion liquid, and other subsequent treatment processes including reduction are not needed, so that the production process is greatly simplified, and the materials and the production cost are saved; (2) the graphene oxide has good adhesion, can improve the peeling strength of a pole piece, is beneficial to inhibiting the peeling of an electrode in a circulating process, reduces side reactions, improves the first efficiency of a battery and prolongs the service life of the battery; (3) the graphene oxide has good adhesion, and the usage amount of an adhesive in the preparation of the negative electrode can be greatly reduced, so that the content of active substances in a pole piece is increased, and the capacity and the energy density of a battery are increased; (4) the graphene oxide is subjected to electrochemical reduction in the first charging process of the battery, so that the conductivity of the graphene oxide is improved, the impedance of a negative electrode is reduced, and the cycling stability of the battery is improved; (5) the flexible structure of the graphene oxide is beneficial to buffering the volume change of the silicon-oxygen cathode material in the charging and discharging processes, the effective contact of the silicon-oxygen cathode and the conductive carbon black particles is ensured, and the cycle life of the battery is prolonged; (6) the preparation process of the negative plate is simple, the process conditions are easy to control and realize, and the method has a great commercial application prospect.
The following is a detailed description of the method for manufacturing the negative electrode sheet according to the present application.
Step S110, preparing a graphene oxide dispersion liquid.
In some embodiments of the present application, a method of preparing a graphene oxide dispersion includes: and carrying out ultrasonic treatment on the graphene oxide slurry in deionized water for 15 to 60 minutes to obtain a uniformly dispersed graphene oxide dispersion liquid.
In some embodiments of the present application, the concentration of the graphene oxide dispersion is 0.01g/L to 0.3 g/L.
In some embodiments of the present application, the number of graphene oxide sheets is 1 to 3. Graphene oxide is generally obtained by oxidizing graphite with strong acid, and the graphene oxide still maintains the layered structure of the graphite after oxidation treatment. The number of layers of the graphene oxide sheets cannot be too large, otherwise, materials are wasted; the number of layers of the graphene oxide sheet cannot be too small, otherwise the silicon cannot be coated well.
In some embodiments of the present application, the graphene oxide flakes are 0.1 to 5 microns in size. The graphene oxide flakes cannot be too large or too small in size, otherwise the silicon is not coated well. It should be noted that the dimensions include a diameter, a length, a width, and the like, and in practice, the shape of the graphene oxide sheet may not be a regular pattern, for example, not a regular circle or rectangle. It should be understood that the dimensions defined by the diameter, length and width described herein are determined by considering the graphene oxide sheet as approximately a circle or rectangle. For example, some graphene oxide flakes may tend to be round, and some graphene oxide flakes may tend to be rectangular.
And step S120, mixing the graphene oxide dispersion liquid with a binder to form a glue solution.
In some embodiments of the present application, the binder comprises sodium carboxymethylcellulose (CMC), styrene butadiene rubber, PAA (polyacrylic acid), PVA (polyvinyl alcohol), PAN (polyacrylonitrile), ALG (sodium alginate), CTS (chitosan), and the like. The binder is used for enhancing the binding strength of other components in the negative electrode slurry and improving the good adhesion of the negative electrode slurry and an adhesion matrix.
And step S130, mixing the glue solution, silica and a conductive agent to form negative electrode slurry.
In some embodiments of the present application, the silicon oxygen is SiOx, wherein 0 < x < 2. Silicon has ultrahigh theoretical gram capacity (4200mAh/g), is rich in silicon resource and low in price, and is used as a main component of a negative electrode material.
In some embodiments of the present application, the conductive agent includes conductive carbon black, conductive graphite, Carbon Nanotubes (CNTs), carbon nanofibers (VGCF), and the like. The conductive agent is used for ensuring that the negative electrode has good charge and discharge performance, and can play a role in collecting micro-current between the negative electrode active substances and the negative electrode current collector so as to reduce the contact resistance of the negative electrode, accelerate the movement rate of electrons and effectively improve the charge and discharge efficiency of the negative electrode.
In some embodiments of the present application, based on the mass of the solute of the negative electrode slurry, the mass ratio of the silicon oxygen is 85% to 98%, the mass ratio of the binder is 1.5% to 11%, the mass ratio of the conductive agent is 1% to 5%, and the mass ratio of the graphene oxide is 0.01% to 0.5%. The graphene oxide has good adhesion, so that the use amount of the adhesive can be greatly reduced, the content of active substances in the pole piece is increased, and the capacity and the energy density of the battery are increased.
In some embodiments of the present application, the negative electrode paste includes silicon oxide, polyacrylic acid, sodium carboxymethyl cellulose, conductive carbon black, and graphene oxide. By taking the mass of the solute of the negative electrode slurry as a reference, the mass proportion of the silica is 85-98%, the mass proportion of the polyacrylic acid is 1-8%, the mass proportion of the sodium carboxymethyl cellulose is 0.5-3%, the mass proportion of the conductive carbon black is 1-5%, and the mass proportion of the graphene oxide is 0.01-0.5%.
And step S140, coating the negative electrode slurry on a negative electrode current collector to form a negative electrode sheet.
In some embodiments of the present application, a method of coating the negative electrode slurry on a negative electrode current collector to form a negative electrode sheet includes: uniformly coating the negative electrode slurry prepared in the step S130 on a negative electrode current collector; drying the negative electrode current collector coated with the negative electrode slurry in a vacuum oven at 90-120 ℃ for 5-12 hours; rolling the negative current collector to enable the negative slurry to be better bonded with the negative current collector; and cutting the negative current collector to obtain a single pole piece.
In some embodiments of the present application, the negative current collector is a foil. In some embodiments of the present application, the foil is made of a material such as metallic copper or metallic aluminum.
In some embodiments of the present application, after the negative electrode slurry is better bonded to the negative electrode current collector by rolling the negative electrode current collector, the compressibility of the negative electrode sheet is 30% to 40%.
According to the negative plate and the manufacturing method thereof, the negative electrode is manufactured by mixing the graphene oxide serving as the functional additive with the silica, the manufacturing method is simple and convenient, the cost is low, and the manufactured negative plate is excellent in performance and has a large commercial application prospect.
The present invention will be described in further detail with reference to specific examples, but the present invention is not limited to these examples, and those skilled in the art can appropriately modify the present invention without changing the scope of the present invention.
Comparative example 1
A method for manufacturing conventional silicon-oxygen negative electrode slurry and a negative electrode plate comprises the following steps:
providing negative electrode slurry, wherein the negative electrode slurry comprises 96 wt% of silica, 1 wt% of polyacrylic acid, 1 wt% of sodium carboxymethylcellulose and 2 wt% of conductive carbon black by taking the mass of a solute of the negative electrode slurry as a reference;
and coating the negative electrode slurry on a copper foil, drying in a vacuum oven at 105 ℃ for 12 hours, and performing rolling cutting to obtain a negative electrode sheet, wherein the compressibility of the negative electrode sheet is 35%.
Example 1
A preparation method of silica and graphene oxide negative electrode slurry and a negative electrode plate comprises the following steps of;
preparing graphene oxide dispersion liquid, and carrying out ultrasonic treatment on graphene oxide slurry in deionized water for 18 minutes to obtain uniformly dispersed graphene oxide dispersion liquid, wherein the concentration of the graphene oxide dispersion liquid is 0.05g/L, the number of layers of graphene oxide sheets is 1-3, and the size of the graphene oxide sheets is 0.1-5 micrometers;
preparing negative electrode slurry, mixing the graphene oxide dispersion liquid with polyacrylic acid and sodium carboxymethylcellulose to form a glue solution, mixing the glue solution with silica and conductive carbon black to form the negative electrode slurry, wherein the negative electrode slurry comprises 96 wt% of silica, 0.9 wt% of polyacrylic acid, 1 wt% of sodium carboxymethylcellulose, 2 wt% of conductive carbon black and 0.1 wt% of graphene oxide based on the solute mass of the negative electrode slurry;
and uniformly coating the negative electrode slurry on a copper foil, drying for 12 hours in a vacuum oven at 105 ℃, and rolling and cutting to obtain a negative electrode sheet, wherein the compressibility of the negative electrode sheet is 35%.
Example 2
A preparation method of silica and graphene oxide negative electrode slurry and a negative electrode plate comprises the following steps of;
preparing graphene oxide dispersion liquid, and carrying out ultrasonic treatment on graphene oxide slurry in deionized water for 25 minutes to obtain uniformly dispersed graphene oxide dispersion liquid, wherein the concentration of the graphene oxide dispersion liquid is 0.1g/L, the number of layers of graphene oxide sheets is 1-3, and the size of the graphene oxide sheets is 0.5-1 micron;
preparing negative electrode slurry, mixing the graphene oxide dispersion liquid with polyacrylic acid and sodium carboxymethylcellulose to form a glue solution, mixing the glue solution with silica and conductive carbon black to form the negative electrode slurry, wherein the negative electrode slurry comprises 96 wt% of silica, 0.95 wt% of polyacrylic acid, 1 wt% of sodium carboxymethylcellulose, 2 wt% of conductive carbon black and 0.05 wt% of graphene oxide based on the solute mass of the negative electrode slurry;
and uniformly coating the negative electrode slurry on a copper foil, drying for 9 hours at 110 ℃ in a vacuum oven, and rolling and cutting to obtain a negative electrode sheet, wherein the compressibility of the negative electrode sheet is 35%.
Battery Performance test 1
The negative electrode sheets in comparative example 1, example 1 and example 2, the metallic lithium positive electrode, the separator and the electrolyte were assembled into a button type half cell, and the first discharge specific capacity and the first charge and discharge efficiency of the cell were measured, and the results are shown in table 1 and fig. 2.
TABLE 1
Specific capacity of first discharge (mAh/g) First charge-discharge efficiency (%)
Comparative example 1 469.9 84.1
Example 1 492.7 84.0
Example 2 481.6 84.6
Table 1 is a table of first discharge performance data of batteries manufactured using the negative electrode sheet in some examples of the present application. Referring to table 1 and fig. 2, the batteries (i.e., examples 1 and 2) composed of the negative electrode sheet manufactured according to the method for manufacturing the negative electrode sheet according to the examples of the present application have higher specific discharge capacity and first charge and discharge efficiency than the battery (i.e., comparative example 1) of the conventional silicon-oxygen negative electrode.
Battery performance test 2
The negative electrode plate and the positive electrode plate in the comparative example 1 and the example 2, and the diaphragm are assembled in a lamination mode, and then are packaged, injected with electrolyte, formed and the like to manufacture the lithium battery. The 1C/1C charge-discharge cycle performance of the lithium battery at room temperature was tested, and the results are shown in FIG. 3.
Referring to fig. 3, the capacity retention rate of the battery composed of the negative electrode sheet manufactured according to the method for manufacturing the negative electrode sheet described in the example of the present application (i.e., example 2) is higher than that of the battery of the conventional silicon-oxygen negative electrode (i.e., comparative example 1).
In view of the above, it will be apparent to those skilled in the art upon reading the present application that the foregoing application content may be presented by way of example only, and may not be limiting. Those skilled in the art will appreciate that the present application is intended to cover various reasonable variations, adaptations, and modifications of the embodiments described herein, although not explicitly described herein. Such alterations, modifications, and variations are intended to be within the spirit and scope of the exemplary embodiments of this application.
It is to be understood that the term "and/or" as used herein in this embodiment includes any and all combinations of one or more of the associated listed items.
It will be further understood that the terms "comprises," "comprising," "includes" or "including," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It will be further understood that, although the terms first, second, third, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, a first element in some embodiments may be termed a second element in other embodiments without departing from the teachings of the present application. The same reference numerals or the same reference characters denote the same elements throughout the specification.
Further, the present specification describes example embodiments with reference to idealized example cross-sectional and/or plan and/or perspective views. Accordingly, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, example embodiments should not be construed as limited to the shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an etched region shown as a rectangle will typically have rounded or curved features. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of exemplary embodiments.

Claims (10)

1. A negative electrode sheet, comprising: the negative electrode comprises a negative electrode current collector and negative electrode slurry coated on the surface of the negative electrode current collector, wherein the negative electrode slurry comprises silica and graphene oxide.
2. The negative electrode sheet according to claim 1, wherein the number of graphene oxide sheets is 1 to 3.
3. The negative electrode sheet of claim 1, wherein the graphene oxide flakes have a size of 0.1 to 5 microns.
4. The negative electrode sheet according to claim 1, wherein the negative electrode slurry further comprises a binder and a conductive agent, and the mass ratio of the silicon to the oxygen is 85% to 98%, the mass ratio of the binder is 1.5% to 11%, the mass ratio of the conductive agent is 1% to 5%, and the mass ratio of the graphene oxide is 0.01% to 0.5%, based on the mass of the solute of the negative electrode slurry.
5. A method for manufacturing a negative plate is characterized by comprising the following steps:
preparing a graphene oxide dispersion liquid;
mixing the graphene oxide dispersion liquid with a binder to form a glue solution;
mixing the glue solution with silica and a conductive agent to form negative electrode slurry;
and coating the negative electrode slurry on a negative electrode current collector to form a negative electrode sheet.
6. The method for manufacturing the negative electrode sheet according to claim 5, wherein the method for preparing the graphene oxide dispersion comprises:
and carrying out ultrasonic treatment on the graphene oxide slurry in deionized water for 15 to 60 minutes to obtain a uniformly dispersed graphene oxide dispersion liquid.
7. The method for manufacturing the negative electrode sheet according to claim 5, wherein the concentration of the graphene oxide dispersion liquid is 0.01g/L to 0.3 g/L.
8. The method for manufacturing the negative electrode sheet according to claim 5, wherein the number of graphene oxide sheets in the graphene oxide dispersion liquid is 1 to 3.
9. The method for manufacturing the negative electrode sheet according to claim 5, wherein the size of the graphene oxide flakes in the graphene oxide dispersion liquid is 0.1 to 5 micrometers.
10. The method for manufacturing the negative electrode plate according to claim 5, wherein the mass ratio of the silicon to the oxygen is 85% to 98%, the mass ratio of the binder is 1.5% to 11%, the mass ratio of the conductive agent is 1% to 5%, and the mass ratio of the graphene oxide is 0.01% to 0.5%, based on the mass of the solute of the negative electrode slurry.
CN202010767885.3A 2020-08-03 2020-08-03 Negative plate and manufacturing method thereof Pending CN111883741A (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107959027A (en) * 2017-11-13 2018-04-24 合肥国轩高科动力能源有限公司 A kind of preparation method of lithium ion battery silicon substrate negative electrode binder and the negative plate containing the binding agent
CN109192543A (en) * 2018-08-16 2019-01-11 中国科学院成都有机化学有限公司 A kind of graphene oxide based binder and preparation method thereof and electrode slice
CN111129479A (en) * 2019-11-25 2020-05-08 陈开兵 Stable silicon-based negative electrode material for lithium battery and preparation method of stable silicon-based negative electrode material

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107959027A (en) * 2017-11-13 2018-04-24 合肥国轩高科动力能源有限公司 A kind of preparation method of lithium ion battery silicon substrate negative electrode binder and the negative plate containing the binding agent
CN109192543A (en) * 2018-08-16 2019-01-11 中国科学院成都有机化学有限公司 A kind of graphene oxide based binder and preparation method thereof and electrode slice
CN111129479A (en) * 2019-11-25 2020-05-08 陈开兵 Stable silicon-based negative electrode material for lithium battery and preparation method of stable silicon-based negative electrode material

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Application publication date: 20201103