CN116093252A - Negative electrode sheet, electrochemical device and electronic device comprising same - Google Patents

Negative electrode sheet, electrochemical device and electronic device comprising same Download PDF

Info

Publication number
CN116093252A
CN116093252A CN202310357947.7A CN202310357947A CN116093252A CN 116093252 A CN116093252 A CN 116093252A CN 202310357947 A CN202310357947 A CN 202310357947A CN 116093252 A CN116093252 A CN 116093252A
Authority
CN
China
Prior art keywords
negative electrode
film layer
electrode film
anions
active material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202310357947.7A
Other languages
Chinese (zh)
Other versions
CN116093252B (en
Inventor
郑歆来
刘涛
李娅洁
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ningde Amperex Technology Ltd
Original Assignee
Ningde Amperex Technology Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ningde Amperex Technology Ltd filed Critical Ningde Amperex Technology Ltd
Priority to CN202310357947.7A priority Critical patent/CN116093252B/en
Publication of CN116093252A publication Critical patent/CN116093252A/en
Application granted granted Critical
Publication of CN116093252B publication Critical patent/CN116093252B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—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
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • 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

Abstract

The application discloses a negative electrode plate, an electrochemical device and an electronic device comprising the same, wherein the negative electrode plate comprises a negative electrode current collector and a negative electrode film layer, the negative electrode film layer is arranged on at least one surface of the negative electrode current collector, the negative electrode film layer comprises a negative electrode active material and a negative electrode additive, the negative electrode additive comprises metal salt, and the metal salt comprises metal cations and nonmetal anions; the metal cations in the metal salt include at least one cation in Li, na, K, mg, ca, ni, co, fe, cu, zn, al, sn; the nonmetallic anions in the metal salt comprise F element and at least one of B element, P element and S element.

Description

Negative electrode sheet, electrochemical device and electronic device comprising same
Technical Field
The application belongs to the technical field of electrochemistry, and particularly relates to a negative electrode plate, an electrochemical device comprising the same and an electronic device.
Background
The lithium ion battery has the advantages of high energy density, high working voltage, small environmental pollution and the like, and is widely applied to the fields of mobile electronic equipment such as mobile phones, digital cameras, notebook computers, unmanned aerial vehicles, intelligent wearing equipment and the like, electric automobiles and the like. Along with the development of modern information technology and the continuous expansion of application fields of lithium ion batteries, the requirements of people on the energy density of the lithium ion batteries are higher and higher. Therefore, providing a lithium ion battery with high energy density and good electrochemical performance and dynamic performance is a technical problem to be solved at present.
Disclosure of Invention
The application provides a negative pole piece, and electrochemical device and electronic device containing the same, which can increase the cohesive force of a negative pole film layer and reduce the thickness rebound of the negative pole piece in the processing process.
The first aspect of the application provides a negative electrode plate, which comprises a negative electrode current collector and a negative electrode film layer, wherein the negative electrode film layer is arranged on at least one surface of the negative electrode current collector, the negative electrode film layer comprises a negative electrode active material and a negative electrode additive, the negative electrode additive comprises a metal salt, and the metal salt comprises a metal cation and a nonmetal anion; the metal cations in the metal salt comprise at least one cation in Li, na, K, mg, ca, ni, co, fe, cu, zn, al, sn; the nonmetallic anions in the metal salt comprise F element and at least one of B element, P element and S element.
The negative electrode film layer contains metal salt, the metal salt can increase cohesive force of the negative electrode film layer, thickness rebound of the negative electrode plate in the processing process is reduced, the prepared negative electrode plate has high compaction density, and further the negative electrode plate has good ionic conductivity, so that the electrochemical device has high energy density, and the cycle performance and high-rate discharge performance of the electrochemical device are improved.
In any embodiment of the present application, the nonmetallic anions in the metal salt comprise at least one of hexafluorophosphate anions, tetrafluoroborate anions, difluorophosphate anions, difluorosulfonimide anions, bistrifluoromethanesulfonimide anions, difluorooxalate borate anions, difluorodioxalate phosphate anions, tetrafluorooxalate phosphate anions, and trifluoromethane sulfonate anions.
In any embodiment of the present application, the non-metal anions in the metal salt comprise at least one of hexafluorophosphate anions, tetrafluoroborate anions, difluorophosphate anions, bis-fluorosulfonyl imide anions, bis-trifluoromethylsulfonyl imide anions.
Therefore, on one hand, the cohesive force of the negative electrode film layer can be increased, the thickness rebound of the negative electrode plate in the processing process is reduced, and on the other hand, the ion conductivity of the negative electrode plate can be improved, so that the electrochemical device can have high energy density, good cycle performance and high-rate discharge performance.
In any embodiment of the present application, the metal cations in the metal salt include at least one cation of Li, na.
In any embodiment of the present application, the weight content of the F element is 0.0035wt% to 2.0wt% based on the total weight of the negative electrode film layer.
In any embodiment herein, the weight content of the F element is 0.32wt% to 1.45wt% based on the total weight of the negative electrode film layer.
When the weight content of the F element in the negative electrode film layer is in the range, the negative electrode plate can have high cohesive force and high adhesive force, so that the thickness rebound of the negative electrode plate in the processing process can be reduced, the electrochemical device can have high energy density, and the cycle performance and high-rate discharge performance of the electrochemical device can be further improved.
In any embodiment of the present application, the total weight content of the F element, the B element, the P element, and the S element is 0.0064wt% to 3.65wt%, based on the total weight of the negative electrode film layer.
In any embodiment of the present application, the total weight content of the F element, the B element, the P element, and the S element is 0.58wt% to 2.2wt% based on the total weight of the negative electrode film layer.
When the total weight content of the F element, the B element, the P element and the S element in the negative electrode film layer is in the range, the negative electrode plate can have high cohesive force and high adhesive force, the thickness rebound of the negative electrode plate in the processing process can be reduced, the electrochemical device can have high energy density, and the cycle performance and the high-rate discharge performance of the electrochemical device can be further improved.
In any embodiment of the present application, the metal salt is present in an amount of 0.01wt% to 9.8wt% based on the total weight of the negative electrode film layer.
In any embodiment of the present application, the metal salt is present in an amount of 1.0wt% to 5.0wt% based on the total weight of the negative electrode film layer.
When the weight content of the metal salt in the negative electrode film layer is in the above range, the negative electrode sheet can have high cohesive force and high adhesive force, which is conducive to reducing the thickness rebound of the negative electrode sheet in the processing process, and the electrochemical device can have high energy density, and the cycle performance and high-rate discharge performance of the electrochemical device can be further improved.
In any embodiment of the present application, the anode active material comprises a first anode active material comprising a first element capable of forming an alloy with Li, the first element comprising at least one of Sn, si, sb, ge. Thus, the electrochemical device can have a high energy density.
In any embodiment of the present application, the first anode active material includes at least one of a simple substance and a compound containing the first element.
In any embodiment of the present application, the first negative electrode active material includes at least one of an elemental silicon material, a silicon oxygen material, a silicon carbon material, a silicon alloy material, an elemental tin material, a tin oxygen material, a tin alloy material, an elemental antimony material, and an elemental germanium material.
In any embodiment of the present application, the anode active material includes a first anode active material and a second anode active material, and the second anode active material includes a carbon material. Therefore, the electric conductivity of the cathode pole piece can be improved, and the cycle performance and high-rate discharge performance of the electrochemical device are improved.
In any embodiment of the present application, the negative electrode active material comprises a first negative electrode active material and a second negative electrode active material, and the second negative electrode active material comprises graphite.
In any embodiment of the present application, the weight content of the first element is denoted as w1, the total weight content of the F element, the B element, the P element, and the S element is denoted as w2, and then w2/w1 is 0.00038 to 2.66, based on the total weight of the negative electrode film layer.
In any embodiment of the present application, the weight content of the first element is denoted as w1, the total weight content of the F element, the B element, the P element, and the S element is denoted as w2, and then w2/w1 is 0.034 to 0.13, based on the total weight of the negative electrode film layer.
When w2/w1 is in the above range, the cohesive force of the negative electrode film layer can be improved, the thickness rebound in the processing process of the negative electrode plate can be reduced, and the energy density of the electrochemical device can be fully exerted.
In any embodiment of the present application, the weight content of the first element is denoted as w1, and w1 is 0.35wt% to 48.0wt% based on the total weight of the negative electrode film layer.
In any embodiment of the present application, the weight content of the first element is denoted as w1, and w1 is 15.5wt% to 25.0wt% based on the total weight of the negative electrode film layer.
When the weight content of the first element in the anode film layer is within the above range, the electrochemical device can be made to have both high energy density and good cycle performance and high rate discharge performance.
In any embodiment of the present application, the cohesion of the negative electrode film layer is 40N/m to 315N/m.
In any embodiment of the present application, the cohesion of the negative electrode film layer is 180N/m to 312N/m.
Therefore, the thickness rebound of the negative electrode plate in the processing process can be effectively reduced.
A second aspect of the present application provides an electrochemical device comprising the negative electrode tab of the first aspect of the present application.
A third aspect of the present application provides an electronic device comprising the electrochemical device of the second aspect of the present application.
The negative electrode film layer in the negative electrode plate provided by the application contains metal salt, the metal salt can increase the cohesive force of the negative electrode film layer, the thickness rebound of the negative electrode plate in the processing process is reduced, the prepared negative electrode plate can be further provided with high compaction density, and further, the negative electrode plate is provided with good ion conductivity, so that the electrochemical device is further provided with high energy density, and the cycle performance and high-rate discharge performance of the electrochemical device are also improved.
Detailed Description
For the purposes of making the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be clearly and completely described below in conjunction with the embodiments, and it is apparent that the described embodiments are some, but not all, embodiments of the present application. The related embodiments described herein are of illustrative nature and are intended to provide a basic understanding of the present application. The examples of the present application should not be construed as limiting the present application. Based on the technical solution provided in the present application and the embodiments given, all other embodiments obtained by a person skilled in the art without making any inventive effort are within the scope of protection of the present application.
For simplicity, only a few numerical ranges are specifically disclosed herein. However, any lower limit may be combined with any upper limit to form a range not explicitly recited; and any lower limit may be combined with any other lower limit to form a range not explicitly recited, and any upper limit may be combined with any other upper limit to form a range not explicitly recited. Furthermore, each separately disclosed point or individual value may itself be combined as a lower limit or upper limit with any other point or individual value or with other lower limit or upper limit to form a range not explicitly recited.
In the description herein, unless otherwise indicated, "above", "below" includes this number.
Unless otherwise indicated, terms used in the present application have well-known meanings commonly understood by those skilled in the art. Unless otherwise indicated, the numerical values of the parameters set forth in this application may be measured by various measurement methods commonly used in the art (e.g., may be tested according to the methods set forth in the examples of this application). Unless otherwise indicated, the test temperatures for each of the parameters mentioned in this application were 25℃and the test pressures were standard atmospheric.
The term "about" is used to describe and illustrate minor variations. When used in connection with an event or circumstance, the terms can refer to instances where the event or circumstance occurs precisely and instances where it occurs to the close approximation. For example, when used in connection with a numerical value, the term can refer to a range of variation of less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. Additionally, amounts, ratios, and other numerical values are sometimes presented herein in a range format. It is to be understood that such range format is used for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited.
The list of items to which the term "at least one of," "at least one of," or other similar terms are connected may mean any combination of the listed items. For example, if items a and B are listed, the phrase "at least one of a and B" means only a; only B; or A and B. In another example, if items A, B and C are listed, then the phrase "at least one of A, B and C" means only a; or only B; only C; a and B (excluding C); a and C (excluding B); b and C (excluding A); or A, B and C. Item a may comprise a single component or multiple components. Item B may comprise a single component or multiple components. Item C may comprise a single component or multiple components.
The term "plurality" refers to two or more.
With the application and popularization of lithium ion batteries, the energy density of the lithium ion batteries is receiving more and more attention. The performance of the anode active material affects the energy density of the lithium ion battery to some extent. The carbon materials such as graphite are the most commonly used cathode active materials at present, and have the advantages of small polarization, stable charge and discharge platforms and the like. However, the performance of commercial graphite is almost developed to the greatest extent at present, and meanwhile, the theoretical specific capacity of graphite is only 372mAh/g, and the energy density of a lithium ion battery adopting carbon materials such as graphite is difficult to further improve due to the limit lithium storage capacity. Therefore, finding a negative active material with a high specific capacity has become an important way to promote the development of lithium ion batteries.
Among various non-carbon anode active materials, anode active materials capable of alloying reaction with lithium, typified by silicon-based materials (e.g., elemental silicon, silicon oxides, silicon alloys, silicon-carbon materials, etc.), have received attention because of their advantage of high theoretical specific capacity. However, a class of negative electrode active materials represented by silicon-based materials (e.g., silicon-based materials, tin-based materials, germanium-based materials, antimony-based materials, etc.) generally have a relatively low compaction density (e.g., far below its theoretical true density), so that during the processing of the negative electrode sheet and the lithium ion battery, the negative electrode sheet prepared from such negative electrode active materials has a serious problem of thickness rebound, thereby resulting in insufficient energy density of the lithium ion battery, and also adversely affecting the assembly and structural design of the lithium ion battery. In addition, the prepared negative electrode plate prepared from the negative electrode active material has smaller compaction density, so that the electric conductivity of the negative electrode plate can be influenced, and the cycle performance and the high-rate discharge performance of the lithium ion battery are influenced.
Therefore, effective technical means are needed to improve the problem of thickness bounce during processing of a class of negative electrode active materials represented by silicon-based materials.
Currently, the improvement strategies for the above problems are mainly focused on the following two aspects: (1) Improving the particle size or morphology of silicon-based materials and the like, for example, nanocrystallizing the particles, adopting non-elemental silicon particles and the like; (2) A negative electrode adhesive having high adhesion is used.
The nano particles have good stacking effect, can alleviate the problem of thickness rebound of the negative electrode plate to a certain extent, and improve the compaction density, but the improvement effect is not ideal enough. Meanwhile, the nano particles are still easy to pulverize in the circulation process, so that the electron and ion conduction paths are invalid, and the circulation performance of the lithium ion battery is poor. In addition, the preparation process of the non-elemental silicon particles, such as silicon oxide, silicon carbon material, etc., is complicated, and after the particle size thereof is reduced to the nano-scale, the preparation process is further complicated and the production cost is greatly increased, thereby seriously affecting the use and commercialization of lithium ion batteries.
The negative electrode adhesive with high adhesion is not ideal in improving the thickness rebound of the negative electrode plate in the processing process, and can influence the high-rate discharge performance of the lithium ion battery.
In view of this, the inventors have improved the negative electrode tab.
Negative pole piece
A first aspect of embodiments of the present application provides a negative electrode tab.
The negative electrode plate comprises a negative electrode current collector and a negative electrode film layer, wherein the negative electrode film layer is arranged on at least one surface of the negative electrode current collector, the negative electrode film layer comprises a negative electrode active material and a negative electrode additive, and the negative electrode additive comprises metal salt.
The metal salts include metal cations and non-metal anions; the metal cations in the metal salt include at least one cation in Li, na, K, mg, ca, ni, co, fe, cu, zn, al, sn; the nonmetallic anions in the metal salt comprise F element and at least one of B element, P element and S element.
The inventors have found in the study that when the negative electrode film layer contains the metal salt, the metal salt can shrink the molecular chains of the negative electrode binder (usually, polymer), improve the morphology of the molecular chains of the negative electrode binder, and make the molecular chains of the negative electrode binder more compact. The metal salt contains an element F, which can form hydrogen bonds with H atoms in the polymer. Therefore, when the negative electrode film layer contains the metal salt, the cohesive force of the negative electrode film layer can be increased, the thickness rebound of the negative electrode plate in the processing process can be reduced, the prepared negative electrode plate can have high compaction density, and further, the negative electrode plate has good ion conductivity, so that the electrochemical device is further facilitated to have high energy density, and the cycle performance and high-rate discharge performance of the electrochemical device can be improved. In addition, the metal salt further includes at least one of B element, P element, S element, which may function to improve ion conductivity and/or to enhance properties of the solid electrolyte interface film, thereby contributing to improvement of cycle performance and high-rate discharge performance of the electrochemical device.
In some embodiments, the metal cations in the metal salt may include at least one cation in Li, na, K, mg. Alternatively, the metal cations in the metal salt may include at least one cation of Li, na.
In some embodiments, the non-metal anions in the metal salt may include hexafluorophosphate anions (PF 6 - ) Tetrafluoroborate anions (BF) 4 - ) Difluorophosphate anion (PO) 2 F 2 - ) Bis-fluorosulfonyl imide anions (FSI) - ) Bis-trifluoromethanesulfonyl imide anion (TFSI) - ) Difluoro oxalato borate anion (DFOB) - ) Difluoro-di-oxalate phosphate anion (DFOP) - ) Tetrafluorooxalate phosphate anion (TFOP) - ) Triflate anions (CF) 3 SO 3 - ) At least one of them.
In some embodiments, the non-metal anions in the metal salt may include hexafluorophosphate anions (PF 6 - ) Tetrafluoroborate anions (BF) 4 - ) Difluorophosphate anion (PO) 2 F 2 - ) Bis-fluorosulfonyl imide anions (FSI) - ) Bis-trifluoromethanesulfonyl imide anion (TFSI) - ) At least one of them.
In some embodiments, the non-metal anions in the metal salt may include hexafluorophosphate anions (PF 6 - ) Tetrafluoroborate anions (BF) 4 - ) Difluorophosphate anion (PO) 2 F 2 - ) At least one of them.
Therefore, on one hand, the cohesive force of the negative electrode film layer can be increased, the thickness rebound of the negative electrode plate in the processing process is reduced, and on the other hand, the ion conductivity of the negative electrode plate can be improved, so that the electrochemical device can have high energy density, good cycle performance and high-rate discharge performance.
In some embodiments, the metal salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluorophosphate, lithium difluorosulfonimide, lithium difluorosulfimide, lithium difluorooxalato borate, lithium difluorodioxaato phosphate, lithium tetrafluorooxalato phosphate, lithium trifluoromethane sulfonate, sodium hexafluorophosphate, sodium tetrafluoroborate, sodium difluorophosphate, sodium difluorosulfonimide, sodium difluoromethanesulfonimide, sodium difluorooxalato borate, sodium difluorodioxaato phosphate, sodium tetrafluorooxalato phosphate, sodium trifluoromethanesulfonate.
In some embodiments, the metal salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluorophosphate, lithium bis-fluorosulfonyl imide, lithium bis-trifluoromethylsulfonyl imide, sodium hexafluorophosphate, sodium tetrafluoroborate, sodium difluorophosphate, sodium bis-fluorosulfonyl imide, sodium bis-trifluoromethylsulfonyl imide.
In some embodiments, the metal salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluorophosphate, sodium hexafluorophosphate, sodium tetrafluoroborate, sodium difluorophosphate.
In some embodiments, the weight content of the F element may be 0.0035wt% to 2.0wt%, based on the total weight of the negative electrode film layer, for example, may be 0.0035wt%, 0.01wt%,0.015wt%,0.02wt%,0.03wt%,0.035wt%,0.04wt%,0.06wt%,0.08wt%,0.1wt%,0.17wt%,0.2wt%,0.3wt%,0.32wt%,0.36wt%,0.4wt%,0.5wt%,0.6wt%,0.7wt%,0.8wt%,0.9wt%,1.0wt%,1.1wt%,1.2wt%,1.3wt%,1.45wt%,1.5wt%,1.6wt%,1.65wt%,1.7wt%,1.8wt%,2.0wt%, or a range of any two values.
In some embodiments, the weight content of the F element may be 0.0035wt% to 1.8wt%,0.10wt% to 1.65wt%,0.32wt% to 1.45wt%, based on the total weight of the negative electrode film layer.
When the weight content of the F element in the negative electrode film layer is in the range, the negative electrode plate can have high cohesive force and high adhesive force, so that the thickness rebound of the negative electrode plate in the processing process can be reduced, the electrochemical device can have high energy density, and the cycle performance and high-rate discharge performance of the electrochemical device can be further improved.
In some embodiments, the total weight content of the F element, B element, P element, S element may be 0.006wt% to 3.7wt%, e.g., may be 0.006wt%,0.0064wt%,0.01wt%,0.06wt%,0.1wt%,0.19wt%,0.31wt%,0.4wt%,0.5wt%,0.58wt%,0.7wt%,0.8wt%,0.88wt%,0.93wt%,1.0wt%,1.2wt%,1.36wt%,1.5wt%,1.64wt%,1.8wt%,2.0wt%,2.2wt%,2.5wt%,3.0wt%,3.3wt%,3.65wt%,3.7wt%, or a range of any two of the foregoing values, based on the total weight of the negative electrode film layer.
In some embodiments, the total weight content of the F element, B element, P element, S element may be 0.0064wt% to 3.65wt%,0.06wt% to 3.3wt%,0.19wt% to 3.0wt%, 0.58wt% to 2.2wt%, based on the total weight of the negative electrode film layer.
When the total weight content of the F element, the B element, the P element and the S element in the negative electrode film layer is in the range, the negative electrode plate can have high cohesive force and high adhesive force, the thickness rebound of the negative electrode plate in the processing process can be reduced, the electrochemical device can have high energy density, and the cycle performance and the high-rate discharge performance of the electrochemical device can be further improved.
In some embodiments, the metal salt may be present in an amount of 0.01wt% to 10wt%, for example, 0.01wt%,0.015wt%,0.02wt%,0.05wt%,0.10wt%,0.2wt%,0.5wt%,1.0wt%,1.5wt%,2.0wt%,2.5wt%,3.0wt%,4.0wt%,5.0wt%,6.0wt%,7.0wt%,8.0wt%,9.0wt%,9.8wt%,10wt%, or a range of any two values described above, based on the total weight of the negative electrode film layer.
In some embodiments, the metal salt may be present in an amount of 0.01wt% to 9.8wt%,0.10wt% to 9.0wt%,0.25wt% to 8.0wt%,0.5wt% to 7.5wt%,1.0wt% to 5.0wt% based on the total weight of the negative electrode film layer.
When the weight content of the metal salt in the negative electrode film layer is in the above range, the negative electrode sheet can have high cohesive force and high adhesive force, which is conducive to reducing the thickness rebound of the negative electrode sheet in the processing process, and the electrochemical device can have high energy density, and the cycle performance and high-rate discharge performance of the electrochemical device can be further improved.
In some embodiments, the anode active material includes a first anode active material, which may include a first element capable of forming an alloy with Li, which may include at least one of Sn, si, sb, ge. Thus, the electrochemical device can have a high energy density.
In some embodiments, the first anode active material may include at least one of a simple substance and a compound including the first element.
In some embodiments, the first negative active material may include at least one of an elemental silicon material, a silicon oxygen material, a silicon carbon material, a silicon alloy material, an elemental tin material, a tin oxygen material, a tin alloy material, an elemental antimony material, an elemental germanium material. Alternatively, the first negative electrode active material may include at least one of an elemental silicon material, a silicon oxygen material, a silicon carbon material, a silicon alloy material, an elemental tin material, a tin oxygen material, and a tin alloy material. More alternatively, the first negative active material may include at least one of a silicon oxygen material, a silicon carbon material, a silicon alloy material, a tin oxygen material, and a tin alloy material. Therefore, the thickness rebound of the negative electrode plate in the processing process can be reduced, and the electrochemical device can have high energy density.
In some embodiments, the anode active material may include both a first anode active material and a second anode active material, and the second anode active material may include a carbon material. The carbon material may include at least one of graphite (e.g., natural graphite, artificial graphite, or a mixture thereof), mesophase micro carbon spheres (MCMB), hard carbon, soft carbon. Therefore, the electric conductivity of the cathode pole piece can be improved, and the cycle performance and high-rate discharge performance of the electrochemical device are improved.
In some embodiments, the anode active material may include both a first anode active material and a second anode active material, and the second anode active material may include graphite, such as natural graphite, artificial graphite, or mixtures thereof, or the like.
In some embodiments, the first negative electrode active material may be present in the negative electrode active material in an amount of 1wt% to 100wt%, for example, 1wt%,5wt%,8wt%,10wt%,15wt%,20wt%,25wt%,30wt%,35wt%,40wt%,45wt%,50wt%,55wt%,60wt%,65wt%,70wt%,80wt%,90wt%,100wt%, or a range consisting of any two of the foregoing.
Alternatively, the weight content of the first negative electrode active material in the negative electrode active material may be 5wt% to 90wt%,10wt% to 75wt%,15wt% to 65wt%,15wt% to 55wt%,20wt% to 55wt%,25wt% to 55wt%,30wt% to 55wt%,35wt% to 55wt%.
This can provide an electrochemical device having both high energy density and good cycle performance and high rate discharge performance.
In some embodiments, the weight content of the first element is denoted as w1, the total weight content of the F element, the B element, the P element, and the S element is denoted as w2, and w2/w1 may be 0.0003 to 2.7, for example, may be 0.0003,0.00038,0.001,0.0018,0.0039,0.007,0.011,0.019,0.026,0.034,0.04,0.059,0.065,0.08,0.096,0.13,0.16,0.18,0.22,0.034,0.39,0.55,0.66,1.0,1.5,2.0,2.66,2.7, or a range of any two values described above, based on the total weight of the negative electrode film layer.
Alternatively, w2/w1 may be 0.00038 to 2.66,0.0039 to 1.0,0.011 to 1.0,0.011 to 0.55,0.011 to 0.18,0.034 to 0.13.
When w2/w1 is in the above range, the cohesive force of the negative electrode film layer can be improved, the thickness rebound in the processing process of the negative electrode plate can be reduced, and the energy density of the electrochemical device can be fully exerted.
In some embodiments, the first element may be present in an amount of 0.35wt% to 50.0wt%, for example, may be 0.35wt%,1.0wt%,1.5wt%,2.2wt%,2.7wt%,4.0wt%,5.0wt%,6.8wt%,8.0wt%,9.0wt%,10.0wt%,12.0wt%,13.5wt%,15.5wt%,16.8wt%,18.0wt%,20.0wt%,22.0wt%,25.0wt%,30.2wt%,35.0wt%,38.3wt%,40.0wt%,46.5wt%,48.0wt%,50.0wt%, or a range of any two of the foregoing values, based on the total weight of the negative electrode film layer.
Alternatively, w1 may be 0.35wt% to 48.0wt%,2.2wt% to 46.5wt%,6.8wt% to 38.3wt%,8.0wt% to 30.2wt%,8.0wt% to 25.0wt%,10.0wt% to 25.0wt%,15.5wt% to 25.0wt%.
When the weight content of the first element in the anode film layer is within the above range, the electrochemical device can be made to have both high energy density and good cycle performance and high rate discharge performance.
The content of F element in the negative electrode film layer can be obtained by SEM-EDX analysis.
The content of the first element (for example, sn element, si element, sb element, ge element), B element, P element, S element, etc. in the negative electrode film layer may be obtained by analysis using inductively coupled plasma emission spectroscopy (ICP-OES).
In some embodiments, the anode film layer may include an anode binder. The specific type of the negative electrode binder is not particularly limited, and may be selected according to the need. As an example, the anode binder may include an aqueous binder.
In some embodiments, the anode binder may include at least one functional group of carboxyl group, hydroxyl group, cyano group, ester group, amine group, amide group. Therefore, the morphology of the molecular chain of the negative electrode adhesive can be better improved through the hydrogen bond action between the metal salt and the negative electrode adhesive, so that the molecular chain of the negative electrode adhesive becomes more compact, the cohesive force of the negative electrode film layer is increased, and the thickness rebound of the negative electrode plate in the processing process is reduced.
In some embodiments, the negative electrode binder may include at least one of styrene-butadiene rubber (SBR), acrylonitrile-based copolymer (e.g., LA-type aqueous binder, optionally LA132, LA 133), polyacrylic acid (PAA) and salts thereof, styrene-acrylic resin, polyvinyl alcohol (PVA), and derivatives thereof, respectively. Derivatives generally refer to products derived from the substitution of hydrogen atoms or radicals in the polymer with other atoms or radicals.
In some embodiments, the weight content of the anode binder may be 0.01wt% to 10wt%,0.5wt% to 10wt%,1wt% to 10wt%,1.5wt% to 9wt% based on the total weight of the anode film layer.
In some embodiments, the anode film layer may include an anode conductive agent. The specific kind of the negative electrode conductive agent is not particularly limited, and may be selected according to the need. For example, the negative electrode conductive agent may include conductive carbon powder. As an example, the negative electrode conductive agent may include, but is not limited to, at least one of conductive carbon black, acetylene Black (AB), ketjen Black (KB), graphite, carbon fiber, carbon tube, graphene, amorphous carbon, hard carbon, soft carbon, glassy carbon, carbon nanofiber, carbon Nanotube (CNT). These materials may be used singly or in combination of two or more.
From the viewpoint of improving electron conductivity, in some embodiments, the anode conductive agent may include at least one of carbon nanofibers and carbon nanotubes.
In some embodiments, the negative electrode conductive agent may include carbon nanotubes. Alternatively, the weight content of the carbon nanotubes in the negative electrode conductive agent may be 30wt% to 100wt%, more alternatively 40wt% to 100wt%.
When the weight content of the carbon nano tube in the negative electrode conductive agent is more than 30wt%, a good conductive path is formed between the negative electrode active material and the negative electrode current collector, and particularly, a good conductive path can be formed in a high-rate charge and discharge process, so that the high-rate discharge performance of the electrochemical device can be improved.
Carbon nanofibers are fibrous carbon materials having an average diameter of several nanometers to several hundred nanometers. Carbon nanofibers having a hollow structure are particularly referred to as carbon nanotubes, which also include single-layer carbon nanotubes, multi-layer carbon nanotubes, and the like. The carbon nanotubes may be prepared by a vapor deposition method, an arc discharge method, a laser evaporation method, etc., to which the embodiments of the present application are not limited.
In some embodiments, the weight content of the negative electrode conductive agent may be 0.01wt% to 1wt%,0.1wt% to 1wt%, based on the total weight of the negative electrode film layer.
In some embodiments, the negative electrode film layer may further include a negative electrode dispersing agent, whereby the film formation quality of the negative electrode film layer may be improved.
In some embodiments, the negative electrode dispersant may include an organic acid. Alternatively, the organic acid may include a carboxyl group and at least one functional group selected from a hydroxyl group, an amino group, and an imino group. Therefore, the cohesive force of the negative electrode film layer can be increased through the hydrogen bond action between the metal salt and the negative electrode dispersing agent, and the thickness rebound of the negative electrode plate in the processing process is reduced.
In some embodiments, the weight average molecular weight of the negative electrode dispersant may be 100000 or less.
In some embodiments, the negative electrode dispersant may include at least one of sodium carboxymethyl cellulose (CMC) and derivatives thereof. Derivatives generally refer to products derived from substitution of a hydrogen atom or group in a polymer with other atoms or groups (e.g., amino groups, etc.).
In some embodiments, the weight content of the anode dispersant may be 0.01wt% to 1wt%,0.1wt% to 1wt%, based on the total weight of the anode film layer.
In some embodiments, the cohesion of the negative electrode film layer may be 40N/m or more, and may be selected from 40N/m to 315N/m,180N/m to 312N/m,200N/m to 312N/m,180N/m to 300N/m, and 200N/m to 300N/m. Therefore, the thickness rebound of the negative electrode plate in the processing process can be effectively reduced.
In some embodiments, the adhesion between the anode film layer and the anode current collector may be 5N/m to 1000N/m, optionally 8N/m to 480N/m. Therefore, the powder falling problem can be effectively reduced.
The negative electrode current collector is provided with two surfaces which are opposite in the thickness direction of the negative electrode current collector, and the negative electrode film layer is arranged on any one or both of the two opposite surfaces of the negative electrode current collector.
In some embodiments, the thickness of the negative electrode film layer may be 30 μm to 150 μm, which is not limited by the embodiments of the present application. The thickness of the negative electrode film layer refers to the thickness of the negative electrode film layer located on one side of the negative electrode current collector.
In some embodiments, the shape of the negative electrode current collector may be plate-like or foil-like, which is not limited by the embodiments of the present application.
In some embodiments, the thickness of the negative electrode current collector may be 4 μm to 25 μm.
In some embodiments, the material of the negative electrode current collector is not particularly limited, and a material having good electron conductivity may be selected. For example, a simple substance or an alloy (for example, stainless steel) containing at least one element of C, cu, ni, fe, V, nb, ti, cr, mo, ru, rh, ta, W, os, ir, pt, au, ag may be used, or a composite material in which a conductive substance is coated with a different conductive substance may be used, and for example, fe may be coated with Cu.
Cu foil, ni foil, stainless steel foil, etc. are optional from the viewpoints of high conductivity, high stability in electrolyte, and good oxidation resistance. Cu foil and Ni foil are optional from the viewpoint of further reducing production cost. Those skilled in the art can adjust the device according to the actual situation.
The negative electrode sheet may be prepared according to conventional methods in the art. The negative electrode active material, the metal salt, and optionally the negative electrode conductive agent, the negative electrode adhesive, the negative electrode dispersing agent, and the like are generally dispersed in a solvent to form a negative electrode slurry, the negative electrode slurry is coated on a negative electrode current collector, and the negative electrode sheet is obtained through procedures such as drying, compacting, and the like. The solvent may include at least one of water, ethanol, acetone, butanone, dimethylformamide, N-methylpyrrolidone, diethylformamide, dimethylsulfoxide, and tetrahydrofuran, which is not limited thereto by the embodiment of the present application.
The coating method may be a known coating method in the art, for example, extrusion coating, gravure coating, micro gravure coating, electrospray, transfer coating, or the like, and the embodiment of the present application is not limited thereto.
The drying method may be a drying method known in the art, and may be a drying method capable of sufficiently volatilizing the solvent in the negative electrode slurry. The drying method may adopt a mode of natural drying, warm air drying, heating drying, far infrared radiation drying, and the like, which is not limited in the embodiment of the present application. The heat treatment may be carried out, for example, in the atmosphere at 50 to 300 ℃.
The compaction can be performed by using a pressing machine (such as a roller press) to enable the coating film to be closely attached to the negative electrode current collector, so that a negative electrode film layer with excellent adhesive force and smooth surface is obtained.
The negative electrode sheet provided in the embodiment of the present application does not exclude other additional functional layers besides the negative electrode film layer. For example, in some embodiments, the negative electrode tab may further include a conductive primer layer (e.g., composed of a conductive agent and an adhesive) interposed between the negative electrode current collector and the negative electrode film layer, disposed on the surface of the negative electrode current collector; in some embodiments, the negative electrode tab may further include a protective layer covering the surface of the negative electrode film layer.
When the parameters (including element content, cohesion, adhesion and the like) of the negative electrode plate or the negative electrode film layer are tested, the negative electrode plate can be directly obtained from a freshly prepared compacted negative electrode plate or from an electrochemical device. In the case of a double-coated negative electrode sheet, the negative electrode film layer on one side may be removed first, for example, by using a doctor blade or the like.
An exemplary method of obtaining a negative electrode tab from an electrochemical device may be as follows: and disassembling the cathode pole piece after the electrochemical device is fully put, soaking the cathode pole piece in an organic solvent (for example, dimethyl carbonate) for a period of time (for example, more than 6 hours), and then taking out the cathode pole piece and drying the cathode pole piece at a certain temperature and for a period of time (for example, more than 2 hours at 80 ℃).
Electrochemical device
A second aspect of the embodiments provides an electrochemical device including any device in which an electrochemical reaction occurs to mutually convert chemical energy and electrical energy, specific examples of which include all kinds of lithium primary batteries or lithium secondary batteries. In particular, the lithium secondary battery includes a lithium ion secondary battery.
During the use of the electrochemical device, an oxidation reaction and a reduction reaction of the electrode active material occur along with charge and discharge. The negative electrode is an electrode in which a reaction takes place in which lithium ions are taken in or lithiated during charging and lithium is released or delithiated during discharging. The positive electrode is an electrode in which a reaction occurs in which lithium ions are released or delithiated during charging and lithium is occluded or lithiated during discharging.
In some embodiments, the electrochemical device may include a positive electrode tab, a negative electrode tab, and an electrolyte, where the negative electrode tab employed by the electrochemical device is a negative electrode tab of the first aspect of the embodiments of the present application. Accordingly, the electrochemical device may have a high energy density, and may also have improved cycle performance and high-rate discharge performance.
[ Positive electrode sheet ]
The materials, composition, and method of making the positive electrode sheet may include any technique known in the art.
In some embodiments, the positive electrode tab may include a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector.
In some embodiments, the positive electrode current collector may have a plate shape or a foil shape, which is not limited in the embodiments of the present application.
In some embodiments, the thickness of the positive electrode current collector may be 6 μm to 25 μm.
In some embodiments, the material of the positive electrode current collector is not particularly limited, and a material having electron conductivity may be selected. For example, a simple substance or an alloy (e.g., stainless steel, etc.) containing at least one element of C, ti, cr, mo, ru, rh, ta, W, os, ir, pt, au, al may be employed.
The C layer, al foil, stainless steel foil, etc. are optional from the viewpoints of high conductivity, high stability in an electrolyte, and good oxidation resistance. The Al foil is optional from the viewpoint of further reducing production costs. Those skilled in the art can adjust the device according to the actual situation.
The positive electrode film layer includes a positive electrode active material. The positive electrode active material may be selected from materials capable of absorbing and releasing lithium. The specific kind of the positive electrode active material is not particularly limited and may be selected according to the need. As an example, the positive electrode active material may include, but is not limited to, lithium iron phosphate (LiFePO 4 ) Lithium manganese phosphate (LiMnPO) 4 ) Lithium cobalt phosphate (LiCoPO) 4 ) Ferric pyrophosphate (Li) 2 FeP 2 O 7 ) Lithium cobalt oxide (LiCoO) 2 ) Spinel type lithium manganate (LiMn) 2 O 4 ) Spinel type nickel manganateLithium (LiNi) 0.5 Mn 1.5 O 4 ) Layered lithium manganate (LiMnO) 2 ) Lithium nickelate (LiNiO) 2 ) Lithium niobate (LiNbO) 2 ) Lithium ferrite (LiFeO) 2 ) Lithium magnesium (LiMgO) 2 ) Lithium calcate (LiCoO) 2 ) Lithium cuprate (LiCuO) 2 ) Lithium zincate (LiZnO) 2 ) Lithium molybdate (LiMoO) 2 ) Lithium tantalate (LiTaO) 2 ) Lithium tungstate (LiWO) 2 ) Lithium nickel cobalt aluminum oxide (LiNi) x Co y Al 1-x-y O 2 ，0<x<1、0<y<1、0<x+y<1, e.g. LiNi 0.8 Co 0.15 Al 0.05 O 2 ) Lithium nickel cobalt manganese oxide (LiNi x Co y Mn 1-x-y O 2 ，0<x<1、0<y<1、0<x+y<1, e.g. LiNi 1/3 Co 1/3 Mn 1/3 O 2 、LiNi 0.5 Co 0.2 Mn 0.3 O 2 、LiNi 0.6 Co 0.2 Mn 0.2 O 2 、LiNi 0.8 Co 0.1 Mn 0.1 O 2 Etc.), lithium-rich materials (e.g., lithium-rich nickel cobalt manganese oxides), manganese oxides (MnO) 2 ) At least one of vanadium oxide, sulfur oxide, silicate oxide, and their respective modified compounds. These materials may be used singly or in combination of two or more.
The modifying compound for each positive electrode active material may be a doping modification, a surface coating modification, or a doping coating simultaneous modification for the positive electrode active material.
In some embodiments, the positive electrode film layer may include a positive electrode conductive agent. The specific kind of the positive electrode conductive agent is not particularly limited, and may be selected according to the need. For example, the positive electrode conductive agent may include conductive carbon powder. As an example, the positive electrode conductive agent may include, but is not limited to, at least one of conductive carbon black, acetylene Black (AB), ketjen Black (KB), graphite, carbon fiber, carbon tube, graphene, amorphous carbon, hard carbon, soft carbon, glassy carbon, carbon nanofiber, carbon Nanotube (CNT). These materials may be used singly or in combination of two or more.
In some embodiments, the positive electrode film layer may include a positive electrode binder. The specific type of the positive electrode binder is not particularly limited, and may be selected as required. As an example, the positive electrode binder may include, but is not limited to, at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polyvinyl alcohol (PVA).
In some embodiments, the thickness of the positive electrode film layer may be 15 μm to 150 μm, which is not limited by the embodiments of the present application. The thickness of the positive electrode film layer refers to the thickness of the positive electrode film layer located on one side of the positive electrode current collector.
The positive electrode sheet may be prepared according to a conventional method in the art. The positive electrode active material, and optionally, the positive electrode conductive agent, the positive electrode adhesive, and the like are generally dispersed in a solvent to form a positive electrode slurry, the positive electrode slurry is coated on a positive electrode current collector, and the positive electrode sheet is obtained through procedures such as drying, compacting, and the like. The solvent may be N-methylpyrrolidone (NMP), but the present application is not limited thereto.
The coating method may be a known coating method in the art, for example, extrusion coating, gravure coating, micro gravure coating, electrospray, transfer coating, or the like, and the embodiment of the present application is not limited thereto.
The drying method may be a drying method known in the art, and may be a method capable of sufficiently volatilizing the solvent in the positive electrode slurry. The drying method may adopt a mode of natural drying, warm air drying, heating drying, far infrared radiation drying, and the like, which is not limited in the embodiment of the present application. The heat treatment may be carried out, for example, in the atmosphere at 50 to 300 ℃.
The compaction can be performed by using a pressing machine (such as a roller press) to tightly attach the coating film to the positive electrode current collector, so as to obtain a positive electrode film layer with excellent adhesive force and smooth surface.
[ electrolyte ]
The electrolyte may be a solid electrolyte, a gel electrolyte, or a liquid electrolyte (also referred to as an electrolyte solution).
The electrolyte may include an electrolyte salt containing lithium ions and a solvent.
The types of the electrolyte salt and the solvent are not particularly limited, and may be selected according to the need.
In some embodiments, as an example, the electrolyte salt may include, but is not limited to, lithium hexafluorophosphate (LiPF 6 ) Lithium perchlorate (LiClO) 4 ) Lithium tetrafluoroborate (LiBF) 4 ) Lithium hexafluoroarsenate (LiAsF) 6 ) At least one of lithium bis (fluorosulfonyl) imide (LiFSI), lithium bis (trifluoromethanesulfonyl) imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalato borate (LiDFOB), and lithium dioxaoxalato borate (LiBOB). The electrolyte salts may be used singly or in combination of two or more.
In some embodiments, the solvent may include at least one of a carbonate compound, a carboxylate compound, an ether compound, and a sulfone compound. As an example, the solvent may include, but is not limited to, at least one of Ethylene Carbonate (EC), propylene Carbonate (PC), ethylmethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), butylene Carbonate (BC), methyl Formate (MF), methyl Acetate (MA), ethyl Acetate (EA), propyl Acetate (PA), methyl Propionate (MP), ethyl Propionate (EP), propyl Propionate (PP), methyl Butyrate (MB), ethyl Butyrate (EB), γ -butyrolactone, sulfolane (SF), dimethylsulfone (MSM), methylsulfone (EMS), diethylsulfone (ESE), methylsulfonyl, dimethylsulfoxide, 2-methyltetrahydrofuran, 1, 3-dioxolane, 4-methyl-1, 3-dioxolane, 1, 2-dimethoxyethane, 1, 2-diethoxyethane, dimethyl ether, diethyl ether, nitromethane, N-dimethylformamide. The above solvents may be used singly or in combination of two or more.
In some embodiments, additives, such as additives that improve various properties of the electrochemical device, may also be included in the electrolyte. Vinylene Carbonate (VC) is optional from the viewpoint of reducing the amount of short-circuit heat generation. The vinylene carbonate may be present in an amount of 0.1wt% to 5wt%, alternatively 0.5wt% to 2wt%, more preferably 0.75wt% to 1.5wt%, based on the total weight of the electrolyte.
The electrolyte may be prepared according to a conventional method in the art. For example, the solvent, electrolyte salt, and optionally other components may be mixed uniformly to obtain the electrolyte. The order of addition of the respective materials is not particularly limited, and for example, an electrolyte salt, and optionally other components and the like may be added to a solvent and mixed uniformly to obtain an electrolyte.
The components of the electrolyte and their contents can be determined according to methods conventional in the art. For example, detection can be performed by gas chromatography-mass spectrometry (GC-MS), ion Chromatography (IC), liquid Chromatography (LC), or the like.
[ diaphragm ]
The electrochemical device may further include a separator. The diaphragm can be arranged between the positive pole piece and the negative pole piece, mainly plays a role in preventing the positive pole and the negative pole from being short-circuited, and can enable lithium ions to pass through. The type of separator is not particularly limited, and any known porous membrane having good chemical stability and mechanical stability may be used.
The shape of the separator may include, but is not limited to, a microporous film, a woven fabric, a nonwoven fabric, a pressed powder, etc., which are optional from the viewpoints of improving output characteristics and mechanical strength.
The separator may be a single-layer film or a multilayer composite film. When the separator is a multilayer composite film, the materials of the layers may be the same or different.
In some embodiments, the separator may include a polymer, an inorganic, etc., formed of a material that is stable to the electrolyte.
For example, the separator may include a substrate layer and an optional surface treatment layer. The substrate layer may include a nonwoven fabric, a film, or a composite film having a porous structure. The material of the base material layer is not particularly limited, and any known electrolyte-stable material may be selected, and materials such as polyethylene, polypropylene, polyamide, polyamideimide, polyimide, polyethylene terephthalate, and ethylene-propylene copolymer are optional from the viewpoint of reducing local heat generation, internal short-circuiting, and melting. As an example, the substrate layer may be selected from a polypropylene porous film, a polyethylene porous film, a polypropylene nonwoven fabric, a polyethylene nonwoven fabric, a polypropylene-polyethylene-polypropylene porous composite film, or the like.
The surface of the base material layer may or may not be provided with a surface treatment layer. In some embodiments, a surface treatment layer may be disposed on at least one surface of the substrate layer, and the surface treatment layer may be a polymer layer or an inorganic layer, or may be a layer formed by mixing a polymer and an inorganic material.
The inorganic layer may include inorganic particles and a binder, and the inorganic particles may include, but are not limited to, at least one of alumina, silica, magnesia, titania, hafnia, tin oxide, ceria, nickel oxide, zinc oxide, calcium oxide, zirconia, yttria, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, barium sulfate. The binder may include, but is not limited to, at least one of polyvinylidene fluoride, a copolymer of vinylidene fluoride-hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoropropylene.
The polymer layer may comprise a polymer, and the material of the polymer may include, but is not limited to, at least one of polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride, and copolymer of vinylidene fluoride-hexafluoropropylene.
In some embodiments, the positive electrode tab, the negative electrode tab, and the separator may be manufactured into an electrode assembly through a winding process or a lamination process.
The electrochemical device further includes an exterior package for packaging the electrode assembly. In some embodiments, the overwrap may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, or the like, or a soft packet, such as a pouch-type soft packet. The soft bag can be made of plastic, such as at least one of polypropylene (PP), polybutylene terephthalate (PBT) and polybutylene succinate (PBS).
Electronic device
A third aspect of embodiments of the present application provides an electronic device comprising the electrochemical device of the second aspect of embodiments of the present application.
The electronic device of the present application is not particularly limited, and may be any electronic device known in the art. In some embodiments, the electronic device may include, but is not limited to, a notebook computer, a pen-input computer, a mobile computer, an electronic book player, a portable telephone, a portable facsimile machine, a portable copier, a portable printer, a headset, a video recorder, a liquid crystal television, a portable cleaner, a portable CD-player, a mini-compact disc, a transceiver, an electronic notepad, a calculator, a memory card, a portable audio recorder, a radio, a backup power source, a motor, an automobile, a motorcycle, a power assisted bicycle, a lighting fixture, a toy, a game machine, a clock, an electric tool, a flash light, a camera, a household large-sized battery, a lithium ion capacitor, and the like.
Examples
The following examples more particularly describe the disclosure of the present application, which are intended as illustrative only, since numerous modifications and variations within the scope of the disclosure will be apparent to those skilled in the art. Unless otherwise indicated, all parts, percentages and ratios reported in the examples below are by weight, and all reagents used in the examples are commercially available or are obtained synthetically according to conventional methods and can be used directly without further treatment, as well as the instruments used in the examples.
Test part
(1) Cohesive force test of negative electrode film layer
Treating (such as scraper) the freshly prepared negative electrode plate into a negative electrode plate with single-sided coating, and then baking for 2 hours at 80 ℃ to sufficiently remove water; cutting a negative electrode plate into a strip-shaped sample with a certain length and width (for example, the length can be 100mm to 160mm and the width can be 20 mm), fixing one side of a negative electrode current collector (for example, copper foil) of the sample on an aluminum plate by using a double-sided adhesive tape, and adhering one side coated with a negative electrode film layer on a PTE adhesive tape; after the sample is prepared, a 180-degree stripping experiment (the stripping surface is consistent with the force line of the tester) is carried out by using a tension tester, the stripping speed is 50mm/min, the force curve in the stripping process is obtained after the complete stripping, and the ratio of the average value of the force in the stable section to the width of the sample is taken as the cohesive force of the negative electrode film layer. To ensure the accuracy of the test results, each negative electrode tab sample was tested at least three times and the average value was taken as the test result. The test instrument may be an Instron 33652 tensile tester.
(2) Thickness test of negative electrode sheet
Manual measurement with a ten-thousandth ruler is a common method for testing the thickness of the negative electrode plate. The specific method comprises the following steps: at least 12 points are randomly taken on the negative electrode plate, the thickness is measured by using a ten-thousandth ruler, and the thickness data of all the points are averaged to obtain the thickness of the negative electrode plate.
The thickness change rate (%) = (H1-H0)/h0×100% of the negative electrode sheet. H0 is the initial thickness of the negative electrode plate, namely the thickness of the freshly prepared rolled negative electrode plate; h1 is the thickness of the disassembled negative electrode plate after the capacity test of the lithium ion battery, namely the thickness after the processing of the negative electrode plate.
(3) Element content test in negative electrode film layer
The F element in the negative electrode film layer can be obtained by SEM-EDX analysis. During testing, the negative electrode plate is tested by using a scanning electron microscope, and the specific operation steps are as follows: and taking a small amount of negative pole piece samples, pasting the negative pole piece samples on conductive adhesive of a sample preparation table, and vacuum drying the negative pole piece samples at 35 ℃ for 6 hours, and then conveying the samples into a sample cabin for testing. The test instrument can be an oxford instrument X-ray spectrometer X-max (the effective crystal area of the probe can be 20 mm) 2 ) And quantitatively analyzing the F element by adopting an EDX-Mapping mode.
The Si element, the B element, the P element and the S element in the negative electrode film layer can be obtained by adopting an inductively coupled plasma emission spectrometry (ICP-OES) method. During testing, a negative electrode plate with the length of 5cm multiplied by 5cm can be cut, materials except a negative electrode current collector are scraped off, weighing is carried out, then a certain amount of concentrated nitric acid (or aqua regia) is added for microwave digestion to obtain a solution, and an inductively coupled plasma emission spectrometer is used for testing. The test instrument may be a Perkin Elmer 7000DV.
(4) Thickness test of lithium ion battery
Manual measurement using a micrometer is one common method used to test the thickness of a lithium ion battery. The specific method comprises the following steps: at least 3 points are randomly taken on the surface of the lithium ion battery, the thickness is measured by using a micrometer, and the thickness data of all the points are averaged to obtain the thickness of the lithium ion battery.
(5) Capacity test of lithium ion battery
Under the constant temperature condition of 25 ℃, constant current charging is carried out on the lithium ion battery to full charge cut-off voltage at the charging multiplying power of 0.2 ℃, and then constant voltage charging is carried out until the current is less than 0.02 ℃ to obtain the charging capacity of the lithium ion battery; and discharging the lithium ion battery to the full discharge cut-off voltage at the constant current of 0.2C to obtain the discharge capacity of the lithium ion battery.
Lithium ion battery volumetric energy density (Wh/L) = (discharge capacity of lithium ion battery x plateau voltage)/volume of lithium ion battery.
To ensure the accuracy of the test results, each sample was tested at least three times and the average was taken as the test result.
Comparative example 1
(1) Preparation of negative electrode plate
The preparation method comprises the steps of mixing a first anode active material silicon carbon material, a second anode active material graphite, anode conductive agent conductive carbon black (Super P), anode adhesive polyacrylic acid (PAA) and anode dispersant sodium carboxymethyl cellulose (CMC) according to a weight ratio of 38:56:5:0.5:0.5 to obtain an initial mixture, and then preparing uniformly dispersed water-based anode slurry with a solid content of 50% by using deionized water as a solvent. And uniformly coating the obtained negative electrode slurry on one surface of a copper foil with the thickness of 6 mu m in a manner of extrusion coating, and baking at the temperature of 100 ℃ to remove solvent deionized water after coating to obtain the negative electrode plate with the negative electrode film thickness of 100 mu m. And repeating the steps on the other surface of the negative electrode plate to obtain the negative electrode plate with the double-sided coating negative electrode film layer. And then rolling the negative electrode plate to obtain the rolled negative electrode plate with the thickness of 81 mu m. The rolled negative electrode sheet was cut into 78.5mm×732mm sheets for use.
(2) Preparation of positive electrode plate
Lithium cobalt oxide (LiCoO) as a positive electrode active material 2 ) Mixing conductive carbon black (Super P) serving as a positive electrode conductive agent and polyvinylidene fluoride (PVDF) serving as a positive electrode adhesive according to a weight ratio of 97.5:1.0:1.5, adding NMP serving as a solvent, preparing positive electrode slurry with a solid content of 75%, and uniformly stirring. And uniformly coating the obtained positive electrode slurry on one surface of an aluminum foil with the thickness of 9 mu m in an extrusion coating mode, and baking at the temperature of 90 ℃ to remove the solvent NMP after coating to obtain the positive electrode plate with the positive electrode film thickness of 100 mu m. And repeating the steps on the other surface of the positive electrode plate to obtain the positive electrode plate with the positive electrode film coated on both sides. And then carrying out rolling treatment on the positive electrode plate to obtain the rolled positive electrode plate with the thickness of 79 mu m. Cutting the rolled positive pole piece into a sheet with the thickness of 77mm multiplied by 735mm for standby.
(3) Preparation of electrolyte
The solvents Ethylene Carbonate (EC), ethylmethyl carbonate (EMC) and diethyl carbonate (DEC) were mixed in a weight ratio of 30:50:20 in a dry argon atmosphere, and then lithium hexafluorophosphate (LiPF) was added to the solvent 6 ) And mixing uniformly to obtain the electrolyte. LiPF (LiPF) 6 The molar concentration in the electrolyte was 1.1mol/L.
(4) Preparation of lithium ion batteries
And taking the PE porous film with the thickness of 7 mu m as a diaphragm, sequentially stacking the prepared positive pole piece, the diaphragm and the negative pole piece, enabling the diaphragm to be positioned between the positive pole and the negative pole to play a role of isolation, and winding to obtain the electrode assembly. And placing the electrode assembly in an outer package, injecting the prepared electrolyte, packaging, and carrying out processes such as formation, degassing and the like to obtain the lithium ion battery.
And taking the rolled negative electrode plate, and testing the cohesive force of the negative electrode film layer according to the method. The cohesion of the negative electrode film layer was 14N/m.
According to the capacity test method, the discharge capacity of the lithium ion battery at 25 ℃ is 3063mAh, the thickness of the lithium ion battery is 5.21mm, and the volumetric energy density of the lithium ion battery is 730Wh/L.
Taking the lithium ion battery after capacity test, disassembling the lithium ion battery to obtain a negative electrode plate, and measuring the thickness of the negative electrode plate to be 109.8 mu m according to the method.
Examples 1-1 to 1-12
The other preparation processes were the same as comparative example 1 except that the preparation process of the negative electrode tab was different.
The negative electrode additive lithium difluorophosphate was added to the initial mixture obtained in comparative example 1, and then a uniformly dispersed aqueous negative electrode slurry having a solid content of 50% was formulated with deionized water as a solvent, and then a negative electrode sheet was prepared according to the preparation process provided in comparative example 1. The amount of lithium difluorophosphate to be used was adjusted so that the weight content of lithium difluorophosphate in the negative electrode film layer was within the range shown in table 1.
The rolled negative electrode sheet was taken, and the content of each element in the negative electrode film layer was tested according to the above-described method, and the results are shown in table 1. The thickness of the processed negative electrode tab, the cohesion of the negative electrode film layer, and the capacity test results of the lithium ion battery are shown in table 2.
TABLE 1
Figure SMS_1
TABLE 2
Figure SMS_2
From the test results in tables 1 and 2, when the negative electrode film layer contains the metal salt additive, the cohesive force of the negative electrode film layer can be improved, and the thickness rebound in the processing process of the negative electrode plate can be reduced.
From the test results in table 1 and table 2, it is also known that when the metal salt content in the negative electrode film layer is between 0.01wt% and 9.8wt%, and optionally between 1.0wt% and 5.0wt%, the cohesive force of the negative electrode film layer can be further improved, the thickness rebound in the processing process of the negative electrode sheet can be reduced, and the lithium ion battery can also achieve high energy density.
Example 2-1
The other preparation processes were the same as comparative example 1 except that the preparation process of the negative electrode tab was different.
And mixing the first anode active material silicon carbon material, the second anode active material graphite, the anode conductive agent conductive carbon black (Super P), the anode adhesive polyacrylic acid (PAA) and the anode dispersant sodium carboxymethyl cellulose (CMC) according to the weight ratio of 0.95:96.05:2:0.5:0.5 to obtain an initial mixture. The negative electrode additive lithium difluorophosphate is added into the initial mixture, and then a solvent deionized water is used for preparing a uniformly dispersed water-based negative electrode slurry with the solid content of 50%, and then a negative electrode plate is prepared according to the preparation process provided in comparative example 1. The amount of lithium difluorophosphate was adjusted so that the weight content of lithium difluorophosphate in the negative electrode film layer was within the range shown in table 3. The test results of the negative electrode tab and the lithium ion battery are shown in tables 3 and 4.
Example 2-2
The other preparation processes were the same as comparative example 1 except that the preparation process of the negative electrode tab was different.
And mixing the first anode active material silicon carbon material, the second anode active material graphite, the anode conductive agent conductive carbon black (Super P), the anode adhesive polyacrylic acid (PAA) and the anode dispersant sodium carboxymethyl cellulose (CMC) according to the weight ratio of 4.8:92.2:2:0.5:0.5 to obtain an initial mixture. The negative electrode additive lithium difluorophosphate is added into the initial mixture, and then a solvent deionized water is used for preparing a uniformly dispersed water-based negative electrode slurry with the solid content of 50%, and then a negative electrode plate is prepared according to the preparation process provided in comparative example 1. The amount of lithium difluorophosphate was adjusted so that the weight content of lithium difluorophosphate in the negative electrode film layer was within the range shown in table 3. The test results of the negative electrode tab and the lithium ion battery are shown in tables 3 and 4.
Examples 2 to 3
The other preparation processes were the same as comparative example 1 except that the preparation process of the negative electrode tab was different.
And mixing the first anode active material silicon carbon material, the second anode active material graphite, the anode conductive agent conductive carbon black (Super P), the anode adhesive polyacrylic acid (PAA) and the anode dispersant sodium carboxymethyl cellulose (CMC) according to the weight ratio of 14.5:82.5:2:0.5:0.5 to obtain an initial mixture. The negative electrode additive lithium difluorophosphate is added into the initial mixture, and then a solvent deionized water is used for preparing a uniformly dispersed water-based negative electrode slurry with the solid content of 50%, and then a negative electrode plate is prepared according to the preparation process provided in comparative example 1. The amount of lithium difluorophosphate was adjusted so that the weight content of lithium difluorophosphate in the negative electrode film layer was within the range shown in table 3. The test results of the negative electrode tab and the lithium ion battery are shown in tables 3 and 4.
Examples 2 to 4
The other preparation processes were the same as comparative example 1 except that the preparation process of the negative electrode tab was different.
And mixing the first anode active material silicon carbon material, the second anode active material graphite, the anode conductive agent conductive carbon black (Super P), the anode adhesive polyacrylic acid (PAA) and the anode dispersant sodium carboxymethyl cellulose (CMC) according to the weight ratio of 32.9:61.1:5:0.5:0.5 to obtain an initial mixture. The negative electrode additive lithium difluorophosphate is added into the initial mixture, and then a solvent deionized water is used for preparing a uniformly dispersed water-based negative electrode slurry with the solid content of 50%, and then a negative electrode plate is prepared according to the preparation process provided in comparative example 1. The amount of lithium difluorophosphate was adjusted so that the weight content of lithium difluorophosphate in the negative electrode film layer was within the range shown in table 3. The test results of the negative electrode tab and the lithium ion battery are shown in tables 3 and 4.
Examples 2 to 5
The other preparation processes were the same as comparative example 1 except that the preparation process of the negative electrode tab was different.
And mixing the first anode active material silicon carbon material, the second anode active material graphite, the anode conductive agent conductive carbon black (Super P), the anode adhesive polyacrylic acid (PAA) and the anode dispersant sodium carboxymethyl cellulose (CMC) according to the weight ratio of 51.7:42.3:5:0.5:0.5 to obtain an initial mixture. The negative electrode additive lithium difluorophosphate is added into the initial mixture, and then a solvent deionized water is used for preparing a uniformly dispersed water-based negative electrode slurry with the solid content of 50%, and then a negative electrode plate is prepared according to the preparation process provided in comparative example 1. The amount of lithium difluorophosphate was adjusted so that the weight content of lithium difluorophosphate in the negative electrode film layer was within the range shown in table 3. The test results of the negative electrode tab and the lithium ion battery are shown in tables 3 and 4.
Examples 2 to 6
The other preparation processes were the same as comparative example 1 except that the preparation process of the negative electrode tab was different.
And mixing the first anode active material silicon carbon material, the second anode active material graphite, the anode conductive agent conductive carbon black (Super P), the anode adhesive polyacrylic acid (PAA) and the anode dispersant sodium carboxymethyl cellulose (CMC) according to the weight ratio of 59.8:32.2:7:0.5:0.5 to obtain an initial mixture. The negative electrode additive lithium difluorophosphate is added into the initial mixture, and then a solvent deionized water is used for preparing a uniformly dispersed water-based negative electrode slurry with the solid content of 50%, and then a negative electrode plate is prepared according to the preparation process provided in comparative example 1. The amount of lithium difluorophosphate was adjusted so that the weight content of lithium difluorophosphate in the negative electrode film layer was within the range shown in table 3. The test results of the negative electrode tab and the lithium ion battery are shown in tables 3 and 4.
Examples 2 to 7
The other preparation processes were the same as comparative example 1 except that the preparation process of the negative electrode tab was different.
Mixing a first anode active material silicon carbon material, a second anode active material graphite, anode conductive agent conductive carbon black (Super P), anode adhesive polyacrylic acid (PAA) and anode dispersant sodium carboxymethyl cellulose (CMC) according to the weight ratio of 69:23:7:0.5:0.5 to obtain an initial mixture. The negative electrode additive lithium difluorophosphate is added into the initial mixture, and then a solvent deionized water is used for preparing a uniformly dispersed water-based negative electrode slurry with the solid content of 50%, and then a negative electrode plate is prepared according to the preparation process provided in comparative example 1. The amount of lithium difluorophosphate was adjusted so that the weight content of lithium difluorophosphate in the negative electrode film layer was within the range shown in table 3. The test results of the negative electrode tab and the lithium ion battery are shown in tables 3 and 4.
Examples 2 to 8
The other preparation processes were the same as comparative example 1 except that the preparation process of the negative electrode tab was different.
Mixing a first anode active material silicon carbon material, a second anode active material graphite, anode conductive agent conductive carbon black (Super P), anode adhesive polyacrylic acid (PAA) and anode dispersant sodium carboxymethyl cellulose (CMC) according to the weight ratio of 81:9:9:0.5:0.5 to obtain an initial mixture. The negative electrode additive lithium difluorophosphate is added into the initial mixture, and then a solvent deionized water is used for preparing a uniformly dispersed water-based negative electrode slurry with the solid content of 50%, and then a negative electrode plate is prepared according to the preparation process provided in comparative example 1. The amount of lithium difluorophosphate was adjusted so that the weight content of lithium difluorophosphate in the negative electrode film layer was within the range shown in table 3. The test results of the negative electrode tab and the lithium ion battery are shown in tables 3 and 4.
Examples 2 to 9
The other preparation processes were the same as comparative example 1 except that the preparation process of the negative electrode tab was different.
And mixing the first anode active material silicon carbon material, anode conductive agent conductive carbon black (Super P), anode adhesive polyacrylic acid (PAA) and anode dispersant sodium carboxymethyl cellulose (CMC) according to the weight ratio of 90:9:0.5:0.5 to obtain an initial mixture. The negative electrode additive lithium difluorophosphate is added into the initial mixture, and then a solvent deionized water is used for preparing a uniformly dispersed water-based negative electrode slurry with the solid content of 50%, and then a negative electrode plate is prepared according to the preparation process provided in comparative example 1. The amount of lithium difluorophosphate was adjusted so that the weight content of lithium difluorophosphate in the negative electrode film layer was within the range shown in table 3. The test results of the negative electrode tab and the lithium ion battery are shown in tables 3 and 4.
TABLE 3 Table 3
Figure SMS_3
TABLE 4 Table 4
Figure SMS_4
As can be seen from the test results of tables 3 and 4, when the content of the metal salt in the anode film layer is the same, the effect of improving the cohesive force of the metal salt on the anode film layer and the effect of suppressing the thickness bounce during the processing of the anode sheet slightly differ when the content of the first anode active material is changed.
The test results in tables 1 to 4 also show that, based on the total weight of the negative electrode film layer, when the ratio w2/w1 of the total weight content of the F element, the B element, the P element and the S element to the weight content of the Si element (i.e., the first element) is between 0.00038 and 2.66, the cohesive force of the negative electrode film layer can be improved, the thickness rebound in the processing process of the negative electrode sheet can be reduced, and the energy density of the lithium ion battery can be fully exerted.
The test results in tables 1 to 4 also show that when the weight content of the Si element is between 15.5wt% and 25.0wt%, and the ratio w2/w1 of the total weight content of the F element, the B element, the P element, and the S element to the weight content of the Si element (i.e., the first element) is between 0.034 and 0.13, the cohesive force of the negative electrode film layer can be further improved, the thickness rebound in the processing process of the negative electrode sheet can be reduced, and the lithium ion battery can also achieve high energy density.
Example 3-1
The preparation process was the same as in examples 1-7 except that lithium tetrafluoroborate was used as the negative electrode additive in the negative electrode sheet. The test results of the negative electrode tab and the lithium ion battery are shown in tables 5 and 6.
Example 3-2
The preparation process was the same as in examples 1-7 except that lithium hexafluorophosphate was used as the negative electrode additive in the negative electrode sheet. The test results of the negative electrode tab and the lithium ion battery are shown in tables 5 and 6.
Examples 3 to 3
The preparation process was the same as in examples 1-7 except that sodium tetrafluoroborate was used as the negative electrode additive in the negative electrode sheet. The test results of the negative electrode tab and the lithium ion battery are shown in tables 5 and 6.
Examples 3 to 4
The preparation process was the same as in examples 1-7 except that lithium difluorosulfimide was used as the negative electrode additive in the negative electrode sheet. The test results of the negative electrode tab and the lithium ion battery are shown in tables 5 and 6.
Comparative example 2
The preparation process was the same as in examples 1-7 except that lithium dioxalate borate was used as the negative electrode additive in the negative electrode sheet. The test results of the negative electrode tab and the lithium ion battery are shown in tables 5 and 6.
TABLE 5
Figure SMS_5
TABLE 6
Figure SMS_6
From the test results in tables 5 and 6, it is clear that the metal salt additive in the negative electrode film layer is in the scope of the present application, but the improvement effect on the cohesive force of the negative electrode film layer and the thickness rebound in the processing process of the negative electrode sheet is slightly different when the types are different. And when the types of the metal salt additives in the negative electrode film layer are out of the application range, the problem of thickness rebound in the processing process of the negative electrode plate cannot be solved, and the energy density of the lithium ion battery cannot be effectively improved.
While the invention has been described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various changes and substitutions of equivalents may be made and equivalents will be apparent to those skilled in the art without departing from the scope of the invention. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (13)

1. A negative electrode tab, comprising:
a negative electrode current collector; and
the negative electrode film layer is arranged on at least one surface of the negative electrode current collector,
wherein, the liquid crystal display device comprises a liquid crystal display device,
the negative electrode film layer comprises a negative electrode active material and a negative electrode additive, wherein the negative electrode additive comprises a metal salt, and the metal salt comprises a metal cation and a nonmetal anion;
the metal cations in the metal salt comprise at least one cation in Li, na, K, mg, ca, ni, co, fe, cu, zn, al, sn;
the nonmetallic anions in the metal salt comprise F element and at least one of B element, P element and S element.
2. The negative electrode tab of claim 1 wherein the non-metal anions in the metal salt comprise at least one of hexafluorophosphate anions, tetrafluoroborate anions, difluorophosphate anions, difluorosulfonimide anions, bistrifluoromethanesulfonimide anions, difluorooxalato borate anions, difluorodioxaoxalato phosphate anions, tetrafluorooxalato phosphate anions, trifluoromethane sulfonate anions.
3. The negative electrode sheet according to claim 2, wherein the metal salt satisfies at least one of the following conditions (1) to (2):
(1) The metal cations in the metal salt comprise at least one cation of Li and Na;
(2) The nonmetallic anions in the metal salt comprise at least one of hexafluorophosphate anions, tetrafluoroborate anions, difluorophosphate anions, difluorosulfimide anions and bistrifluoromethylsulfonimide anions.
4. The negative electrode sheet according to any one of claims 1 to 3, wherein the negative electrode film layer satisfies at least one of the following conditions (1) to (3):
(1) The weight content of F element is 0.0035wt% to 2.0wt% based on the total weight of the negative electrode film layer;
(2) The total weight content of F element, B element, P element and S element is 0.0064wt% to 3.65wt% based on the total weight of the negative electrode film layer;
(3) The metal salt is contained in an amount of 0.01 to 9.8wt% based on the total weight of the negative electrode film layer.
5. The negative electrode tab of claim 4, wherein the negative electrode film layer satisfies at least one of the following conditions (1) to (3):
(1) The weight content of F element is 0.32wt% to 1.45wt% based on the total weight of the negative electrode film layer;
(2) The total weight content of F element, B element, P element and S element is 0.58wt% to 2.2wt% based on the total weight of the negative electrode film layer;
(3) The metal salt is contained in an amount of 1.0 to 5.0wt% based on the total weight of the negative electrode film layer.
6. The negative electrode tab of claim 1, wherein the negative electrode active material comprises a first negative electrode active material comprising a first element capable of forming an alloy with Li, the first element comprising at least one of Sn, si, sb, ge.
7. The negative electrode sheet according to claim 6, wherein the negative electrode active material satisfies at least one of the following conditions (1) to (4):
(1) The first anode active material includes at least one of a simple substance and a compound containing the first element;
(2) The first negative electrode active material comprises at least one of a simple substance silicon material, a silicon oxygen material, a silicon carbon material, a silicon alloy material, a simple substance tin material, a tin oxygen material, a tin alloy material, a simple substance antimony material and a simple substance germanium material;
(3) The anode active material includes a first anode active material and a second anode active material, and the second anode active material includes a carbon material;
(4) The anode active material includes a first anode active material and a second anode active material, and the second anode active material includes graphite.
8. The negative electrode tab according to claim 6 or 7, wherein the negative electrode film layer satisfies at least one of the following conditions (1) to (2):
(1) The weight content of the first element is denoted as w1, the total weight content of the F element, the B element, the P element and the S element is denoted as w2, and then w2/w1 is 0.00038 to 2.66 based on the total weight of the negative electrode film layer;
(2) The weight content of the first element is denoted as w1, w1 is 0.35 to 48.0wt% based on the total weight of the negative electrode film layer.
9. The negative electrode tab of claim 8, wherein the negative electrode film layer satisfies at least one of the following conditions (1) to (2):
(1) The weight content of the first element is denoted as w1, the total weight content of the F element, the B element, the P element and the S element is denoted as w2, and then w2/w1 is 0.034 to 0.13 based on the total weight of the negative electrode film layer;
(2) The weight content of the first element is denoted as w1, w1 is 15.5wt% to 25.0wt% based on the total weight of the negative electrode film layer.
10. The negative electrode tab of claim 1, wherein the cohesion of the negative electrode film layer is 40N/m to 315N/m.
11. The negative electrode tab of claim 10, wherein the cohesion of the negative electrode film layer is 180N/m to 312N/m.
12. An electrochemical device comprising the negative electrode tab according to any one of claims 1 to 11.
13. An electronic device comprising the electrochemical device according to claim 12.
CN202310357947.7A 2023-04-06 2023-04-06 Negative electrode sheet, electrochemical device and electronic device comprising same Active CN116093252B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310357947.7A CN116093252B (en) 2023-04-06 2023-04-06 Negative electrode sheet, electrochemical device and electronic device comprising same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310357947.7A CN116093252B (en) 2023-04-06 2023-04-06 Negative electrode sheet, electrochemical device and electronic device comprising same

Publications (2)

Publication Number Publication Date
CN116093252A true CN116093252A (en) 2023-05-09
CN116093252B CN116093252B (en) 2023-06-27

Family

ID=86206732

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310357947.7A Active CN116093252B (en) 2023-04-06 2023-04-06 Negative electrode sheet, electrochemical device and electronic device comprising same

Country Status (1)

Country Link
CN (1) CN116093252B (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117133859A (en) * 2023-10-23 2023-11-28 宁德时代新能源科技股份有限公司 Negative electrode plate, battery cell, battery and electricity utilization device
CN117316656A (en) * 2023-11-13 2023-12-29 延安大学 Preparation method and application of multi-element doped molybdate@cobaltate nano-array hybridized core-shell structure material

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107565135A (en) * 2016-06-30 2018-01-09 江苏国泰超威新材料有限公司 Application, lithium ion cell electrode, its preparation method and application of a kind of fluorophosphates in lithium ion cell electrode is prepared
CN110582871A (en) * 2017-02-20 2019-12-17 纳米技术仪器公司 Lithium secondary battery containing protected anode active material particles and method of manufacturing the same
CN110710023A (en) * 2017-04-10 2020-01-17 纳米技术仪器公司 Lithium metal secondary battery containing polymer layer for protecting anode and manufacturing method thereof
WO2020041559A1 (en) * 2018-08-22 2020-02-27 Global Graphene Group, Inc. Electrochemically stable elastomer-encapsulated particles of cathode active materials for lithium batteries
US20200119353A1 (en) * 2018-10-15 2020-04-16 Nanotek Instruments, Inc. Electrochemically stable anode particulates for lithium secondary batteries
WO2020081379A1 (en) * 2018-10-15 2020-04-23 Global Graphene Group, Inc. Electrochemically stable anode particulates for lithium secondary batteries and method of production
CN113793918A (en) * 2021-09-08 2021-12-14 远景动力技术(江苏)有限公司 Lithium ion battery and preparation method thereof
CN113851724A (en) * 2021-09-22 2021-12-28 宁德新能源科技有限公司 Electrochemical device and electronic device
WO2023048550A1 (en) * 2021-09-27 2023-03-30 주식회사 엘지화학 Cathode additive for lithium secondary battery, method for preparing same, cathode comprising same, and lithium secondary battery

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107565135A (en) * 2016-06-30 2018-01-09 江苏国泰超威新材料有限公司 Application, lithium ion cell electrode, its preparation method and application of a kind of fluorophosphates in lithium ion cell electrode is prepared
CN110582871A (en) * 2017-02-20 2019-12-17 纳米技术仪器公司 Lithium secondary battery containing protected anode active material particles and method of manufacturing the same
CN110710023A (en) * 2017-04-10 2020-01-17 纳米技术仪器公司 Lithium metal secondary battery containing polymer layer for protecting anode and manufacturing method thereof
WO2020041559A1 (en) * 2018-08-22 2020-02-27 Global Graphene Group, Inc. Electrochemically stable elastomer-encapsulated particles of cathode active materials for lithium batteries
US20200119353A1 (en) * 2018-10-15 2020-04-16 Nanotek Instruments, Inc. Electrochemically stable anode particulates for lithium secondary batteries
WO2020081379A1 (en) * 2018-10-15 2020-04-23 Global Graphene Group, Inc. Electrochemically stable anode particulates for lithium secondary batteries and method of production
CN113793918A (en) * 2021-09-08 2021-12-14 远景动力技术(江苏)有限公司 Lithium ion battery and preparation method thereof
CN113851724A (en) * 2021-09-22 2021-12-28 宁德新能源科技有限公司 Electrochemical device and electronic device
WO2023048550A1 (en) * 2021-09-27 2023-03-30 주식회사 엘지화학 Cathode additive for lithium secondary battery, method for preparing same, cathode comprising same, and lithium secondary battery

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117133859A (en) * 2023-10-23 2023-11-28 宁德时代新能源科技股份有限公司 Negative electrode plate, battery cell, battery and electricity utilization device
CN117316656A (en) * 2023-11-13 2023-12-29 延安大学 Preparation method and application of multi-element doped molybdate@cobaltate nano-array hybridized core-shell structure material
CN117316656B (en) * 2023-11-13 2024-04-16 延安大学 Preparation method and application of multi-element doped molybdate@cobaltate nano-array hybridized core-shell structure material

Also Published As

Publication number Publication date
CN116093252B (en) 2023-06-27

Similar Documents

Publication Publication Date Title
US9034521B2 (en) Anode material of excellent conductivity and high power secondary battery employed with the same
US9531008B2 (en) Positive electrode for a lithium battery and lithium battery employing the same
JP5150966B2 (en) Non-aqueous electrolyte secondary battery positive electrode and non-aqueous electrolyte secondary battery using the same
CN116093252B (en) Negative electrode sheet, electrochemical device and electronic device comprising same
JP6188158B2 (en) Negative electrode for lithium ion secondary battery, negative electrode slurry for lithium ion secondary battery, and lithium ion secondary battery
US20120045696A1 (en) Negative electrode materials for non-aqueous electrolyte secondary battery
CN114068864B (en) Negative pole piece and electrochemical device and electronic equipment comprising same
KR101590678B1 (en) Anode Active Material for Lithium Secondary Battery and Lithium Secondary Battery Comprising the Same
CN113812021A (en) Electrochemical device and electronic device
CN113451550A (en) Positive electrode for nonaqueous electrolyte secondary battery, nonaqueous electrolyte secondary battery provided with same, and module or battery system
US8586247B2 (en) Positive electrode active material comprising an agglomeration of at least two primary particles for lithium battery and lithium battery using the same
CN114824165B (en) Negative electrode plate, electrochemical device and electronic equipment
CN116472622A (en) Negative electrode active material, method of preparing the same, and negative electrode tab, electrochemical device and electronic device including the same
KR101122938B1 (en) Preparation method of electrode active material particle
CN115398667A (en) Electrode, method of manufacturing the same, electrochemical device, and electronic device
CN116960280B (en) Negative electrode sheet, method of manufacturing the same, electrochemical device and electronic device including the same
JP2017134974A (en) Lithium secondary battery
CN115036464B (en) Electrochemical device and power utilization device
CN116960280A (en) Negative electrode sheet, method of manufacturing the same, electrochemical device and electronic device including the same
JP7459369B2 (en) Modified silicon materials and manufacturing methods, negative electrode materials, negative electrode plates, secondary batteries, battery modules, battery packs, and power consumption devices
WO2011123519A1 (en) Negative electrode materials for non-aqueous electrolyte secondary battery
CN117941100A (en) Electrochemical device and electronic device
CN114497558A (en) Electrochemical device and electronic device
CN117438535A (en) Negative pole piece, secondary battery and electric equipment
CN117728013A (en) Lithium ion battery

Legal Events

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