WO2024011371A1 - 用于正极极片的粘结剂及其合成方法、以及包含其的正极极片、二次电池及用电装置 - Google Patents

用于正极极片的粘结剂及其合成方法、以及包含其的正极极片、二次电池及用电装置 Download PDF

Info

Publication number
WO2024011371A1
WO2024011371A1 PCT/CN2022/104982 CN2022104982W WO2024011371A1 WO 2024011371 A1 WO2024011371 A1 WO 2024011371A1 CN 2022104982 W CN2022104982 W CN 2022104982W WO 2024011371 A1 WO2024011371 A1 WO 2024011371A1
Authority
WO
WIPO (PCT)
Prior art keywords
acrylate
methacrylate
monomer
group
mol
Prior art date
Application number
PCT/CN2022/104982
Other languages
English (en)
French (fr)
Inventor
叶冲
孙成栋
郑义
解来勇
Original Assignee
宁德时代新能源科技股份有限公司
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 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to PCT/CN2022/104982 priority Critical patent/WO2024011371A1/zh
Publication of WO2024011371A1 publication Critical patent/WO2024011371A1/zh

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • 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

Definitions

  • the present application belongs to the field of battery technology, and specifically relates to a binder for a positive electrode sheet and a synthesis method thereof, as well as a positive electrode sheet, a secondary battery and an electrical device containing the same.
  • PVDF polyvinylidene fluoride
  • the purpose of this application is to provide a binder for a positive electrode sheet and a synthesis method thereof, as well as a positive electrode sheet, a secondary battery and an electrical device containing the same.
  • the binder not only has good flexibility and It has high adhesion and good electrolyte swelling resistance.
  • a first aspect of the present application provides a binder for a positive electrode sheet, including a copolymer formed from a comonomer, wherein the comonomer includes a first monomer, a second monomer, and a third monomer. and a fourth monomer, the first monomer includes one or more compounds represented by Formula 1, the second monomer includes one or more compounds represented by Formula 2, and the The third monomer includes one or more compounds represented by Formula 3, and the fourth monomer includes one or more compounds represented by Formula 4,
  • R 11 to R 13 , R 21 to R 23 , R 31 to R 33 , and R 41 to R 43 each independently represent a hydrogen atom, a halogen atom, an acid halide group, a nitro group, a cyano group, a carboxyl group, a hydroxyl group, and R a At least one of the group consisting of the following substituted or unsubstituted groups: C1 ⁇ C6 alkyl, C2 ⁇ C6 alkenyl, C1 ⁇ C6 alkoxy, C1 ⁇ C6 alkylthio, C3 ⁇ C6 cycloalkyl , C3 ⁇ C6 heterocycloalkyl group, R 14 represents C10 ⁇ C30 alkyl group, C10 ⁇ C30 alkenyl group substituted or unsubstituted by R a , R 24 represents C1 ⁇ C9 alkyl group, C2 substituted or unsubstituted by R a ⁇ C9 alkenyl group, R 34 represents a hydrogen atom
  • the binder provided by this application not only has good flexibility and high adhesion, but also has good electrolyte swelling resistance.
  • a first monomer unit with a similar structure to Formula 1 in the binder the difference from the first monomer is that the carbon-carbon double bond is opened during copolymerization
  • the electrolyte swelling resistance of the binder can be better improved and flexibility
  • a second monomer unit with a similar structure to Formula 2 in the binder the difference from the second monomer is that the carbon-carbon double bond is opened during copolymerization
  • the adhesiveness of the binder can be increased
  • a third monomer unit with a similar structure to formula 3 in the binder the difference from the third monomer is that the carbon-carbon double bond is opened during copolymerization
  • the adhesiveness of the binder can be increased and the binder can be improved Affinity with the positive electrode active material, conductive agent and positive electrode current collector
  • a fourth monomer unit with a similar structure to Formula 4 in the binder the difference from the first monomer is
  • the molar content of the second monomer is 1 mol% to 30 mol%, optionally 8 mol% to 30 mol%. This helps the adhesive to have better adhesion.
  • the molar content of the third monomer is 1 mol% to 10 mol%, optionally 3 mol% to 10 mol%. This is beneficial to the binder having better adhesion, and is also beneficial to further improving the affinity between the binder and the positive electrode active material, the conductive agent and the positive electrode current collector.
  • the molar content of the fourth monomer is 50 mol% to 95 mol%, optionally 60 mol% to 84 mol%. This helps the binder to have better electrolyte swelling resistance.
  • R 11 to R 13 each independently represents a hydrogen atom, a halogen atom, an acid halide group, a nitro group, a cyano group, a carboxyl group, a C1 to C6 alkyl group, or a C1 to C6 haloalkyl group.
  • Optional Ground, R 11 to R 13 all represent hydrogen atoms.
  • R 21 to R 23 each independently represents a hydrogen atom, a halogen atom, an acid halide group, a nitro group, a cyano group, a carboxyl group, a C1 to C6 alkyl group, or a C1 to C6 haloalkyl group, optionally Ground, R 21 to R 23 all represent hydrogen atoms.
  • R 31 to R 33 each independently represents a hydrogen atom, a halogen atom, an acid halide group, a nitro group, a cyano group, a carboxyl group, a C1 to C6 alkyl group, or a C1 to C6 haloalkyl group.
  • Optional Ground, R 31 to R 33 all represent hydrogen atoms.
  • R 41 to R 43 each independently represents a hydrogen atom, a halogen atom, an acid halide group, a nitro group, a cyano group, a carboxyl group, a C1 to C6 alkyl group, or a C1 to C6 haloalkyl group, optionally Ground, R 41 to R 43 all represent hydrogen atoms.
  • R 14 represents a C14-C22 alkyl group or a C14-C22 alkenyl group substituted or unsubstituted by R a , and optionally represents a dodecyl group or a ten group substituted or unsubstituted by R a . Tetraalkyl, hexadecyl, octadecyl, eicosanyl, behenyl.
  • the side chain R 14 represents an even number of carbon atoms, the binder is easier to crystallize, and the formed grains are more regular, which can improve the binder's resistance to electrolyte swelling, and the binder can also have better of flexibility.
  • the first monomer includes decyl acrylate, isodecyl acrylate, undecyl acrylate, dodecyl acrylate, tridecyl acrylate, tetradecyl acrylate ester, pentadecyl acrylate, cetyl acrylate, heptadecyl acrylate, stearyl acrylate, isostearyl acrylate, nonadecyl acrylate, 2-methyl acrylate Nonadecyl acrylate, eicosanyl acrylate, behenyl acrylate, behenyl acrylate, oleyl methacrylate, decyl methacrylate, isodecyl methacrylate, methacrylate Undecyl methacrylate, dodecyl methacrylate, 2-butyloctyl methacrylate, tridecyl methacrylate, myristyl methacrylate, ten
  • the second monomer includes methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, amyl acrylate, isoamyl acrylate , hexyl acrylate, ethylhexyl acrylate, heptyl acrylate, octyl acrylate, isooctyl acrylate, nonyl acrylate, isononyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, methyl acrylate Methyl acrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, hydroxyethyl caprolactone methacrylate, butyl methacrylate, isobutyl methacrylate, amyl methacrylate,
  • the third monomer includes acrylic acid, itaconic acid, ⁇ -(acryloyloxy)propionic acid, maleic acid, fumaric acid, lithium acrylate, sodium acrylate, methacrylic acid, One or more of lithium methacrylate and sodium methacrylate, optionally including acrylic acid, itaconic acid, ⁇ -(acryloyloxy)propionic acid, maleic acid, fumaric acid, lithium acrylate, and sodium acrylate one or more of them.
  • the fourth monomer includes acrylonitrile, methacrylonitrile, trifluoromethylacrylonitrile, ethacrylonitrile, 2-chloroacrylonitrile, 2-methyl-2-butan One or more acrylonitriles, optionally including acrylonitrile.
  • the comonomer further includes a fifth monomer, and the fifth monomer includes an acrylamide monomer, an aliphatic monoolefin monomer, and an aliphatic conjugated diene monomer. one or more of the species.
  • the acrylamide monomer includes one or more of acrylamide, methacrylamide, hydroxymethylacrylamide, and hydroxyethylacrylamide; optionally, the aliphatic monoolefins
  • the monomers include one or more of halogen-substituted or unsubstituted ethylene, propylene, and butylene; optionally, the aliphatic conjugated diene monomers include halogen-substituted or unsubstituted butadiene, isopropylene, One or more pentadienes.
  • the binder further includes one or more of a dispersant, an initiator, and a chain transfer agent.
  • the dispersant is an organic dispersant, and more optionally includes one or more of polyvinyl alcohol, gelatin, carboxymethylcellulose, polyethylene glycol, and polyacrylate;
  • the initiator is an oil-soluble initiator, and more optionally includes one or more of azo initiators and organic peroxy initiators;
  • the chain transfer agent includes dodecyl sulfide One or more of alcohol, cetyl mercaptan, and octadecyl mercaptan.
  • the weight average molecular weight of the binder is 100,000 to 1,000,000, optionally 100,000 to 500,000. This is beneficial to the binder having good adhesion, and is also beneficial to the preparation of positive electrode slurry.
  • the glass transition temperature of the binder is below 50°C, and may be selected from 0°C to 50°C.
  • the binder has better flexibility and can effectively prevent the cathode active material layer from cracking and falling off.
  • the swelling degree of the adhesive when soaked in a carbonate solvent in a 25° C. environment for 7 days is between 10% and 70%.
  • the swelling degree of the adhesive when soaked in a carbonate solvent in a 60° C. environment for 3 days is between 15% and 100%.
  • the carbonate solvent is configured as follows: ethylene carbonate, dimethyl carbonate and diethyl carbonate are uniformly mixed at a mass ratio of 20:30:50.
  • the binder provided by this application has low solubility in the electrolyte, thereby enabling the positive electrode plate to maintain good structural stability during long-term charging and discharging processes.
  • the second aspect of this application provides a method for synthesizing the adhesive of the first aspect of this application, including the following steps:
  • the comonomers include a first monomer, a second monomer, a third monomer and a fourth monomer, and the first monomer includes one of the compounds shown in Formula 1 or more, the second monomer includes one or more compounds represented by Formula 2, the third monomer includes one or more compounds represented by Formula 3, and the fourth monomer
  • the monomer includes one or more compounds represented by formula 4,
  • R 11 to R 13 , R 21 to R 23 , R 31 to R 33 , and R 41 to R 43 each independently represent a hydrogen atom, a halogen atom, an acid halide group, a nitro group, a cyano group, a carboxyl group, a hydroxyl group, and R a At least one of the group consisting of the following substituted or unsubstituted groups: C1 ⁇ C6 alkyl, C2 ⁇ C6 alkenyl, C1 ⁇ C6 alkoxy, C1 ⁇ C6 alkylthio, C3 ⁇ C6 cycloalkyl , C3 ⁇ C6 heterocycloalkyl group, R 14 represents C10 ⁇ C30 alkyl group, C10 ⁇ C30 alkenyl group substituted or unsubstituted by R a , R 24 represents C1 ⁇ C9 alkyl group, C2 substituted or unsubstituted by R a ⁇ C9 alkenyl group, R 34 represents a hydrogen atom
  • comonomer suspension polymerization Add dispersant and deionized water to the reaction kettle, pass inert gas below the liquid level of the reaction kettle, raise the temperature to the reaction temperature under stirring, and then add the comonomer under stirring.
  • the polymerization reaction is carried out using a polymer, an initiator and a chain transfer agent. After the reaction is completed, a polymer dispersion is obtained. The obtained polymer dispersion is then filtered, washed and dried to obtain the binder.
  • the binder can be synthesized through suspension polymerization, and the obtained binder has the advantage of narrow molecular weight distribution.
  • the comonomer further includes a fifth monomer, and the fifth monomer includes an acrylamide monomer, an aliphatic monoolefin monomer, and an aliphatic conjugated diene monomer. one or more of the species.
  • the reaction temperature is 65°C to 85°C.
  • reaction time is from 2 hours to 8 hours.
  • the stirring speed is 200 rpm to 400 rpm.
  • the dispersant is an organic dispersant, optionally including one or more of polyvinyl alcohol, gelatin, carboxymethyl cellulose, polyethylene glycol, and polyacrylate.
  • the initiator is an oil-soluble initiator, optionally including one or more of azo initiators and organic peroxy initiators.
  • the chain transfer agent includes one or more of dodecyl mercaptan, cetyl mercaptan, and octadecyl mercaptan.
  • the mass percentage of the dispersant is 0.1 to 2 wt% based on the total mass of the comonomer being 100 wt%.
  • the mass percentage of the initiator is 1 to 10 wt% based on the total mass of the comonomer being 100 wt%.
  • the mass percentage of the chain transfer agent is 1 to 5 wt% based on the total mass of the comonomer being 100 wt%.
  • a third aspect of the present application provides a positive electrode sheet, including a positive current collector and a positive active material layer located on at least one surface of the positive current collector, wherein the positive active material layer includes the binder of the first aspect of the present application. Or a binder synthesized by the method of the second aspect of the present application.
  • the bonding strength between the cathode active material layer and the cathode current collector is ⁇ 8 N/m.
  • a fourth aspect of the present application provides a secondary battery, including the positive electrode plate of the third aspect of the present application.
  • a fifth aspect of the present application provides an electrical device, including the secondary battery of the fourth aspect of the present application.
  • the binder provided by this application not only has good flexibility and high adhesion, but also has good electrolyte swelling resistance, thereby ensuring that the positive electrode plate has high bonding strength and good processing performance, while ensuring that the two
  • the secondary battery still has good structural stability during long-term charging and discharging, which is conducive to the full play of the electrochemical performance of the secondary battery.
  • the electrical device of the present application includes the secondary battery provided by the present application, and thus has at least the same advantages as the secondary battery.
  • FIG. 1 is a schematic diagram of an embodiment of the secondary battery of the present application.
  • FIG. 2 is an exploded schematic view of the embodiment of the secondary battery of FIG. 1 .
  • FIG. 3 is a schematic diagram of an embodiment of the battery module of the present application.
  • FIG. 4 is a schematic diagram of an embodiment of the battery pack of the present application.
  • FIG. 5 is an exploded schematic view of the embodiment of the battery pack shown in FIG. 4 .
  • FIG. 6 is a schematic diagram of an embodiment of a power consumption device including the secondary battery of the present application as a power source.
  • Figure 7 is an infrared spectrum of the adhesive synthesized in Example 2.
  • Ranges disclosed herein are defined in terms of lower and upper limits. A given range is defined by selecting a lower limit and an upper limit that define the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive of the endpoints, and may be arbitrarily combined, that is, any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, understand that ranges of 60-110 and 80-120 are also expected. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2- 3, 2-4 and 2-5.
  • the numerical range “a-b” represents an abbreviated representation of any combination of real numbers between a and b, where a and b are both real numbers.
  • the numerical range “0-5" means that all real numbers between "0-5" have been listed in this article, and "0-5" is just an abbreviation of these numerical combinations.
  • a certain parameter is an integer ⁇ 2
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially.
  • step (c) means that step (c) may be added to the method in any order.
  • the method may include steps (a), (b) and (c). , may also include steps (a), (c) and (b), may also include steps (c), (a) and (b), etc.
  • condition "A or B” is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists) ; Or both A and B are true (or exist).
  • C1-C6 alkyl is expressly contemplated to separately disclose C1, C2, C3, C4, C5, C6, C1-C6, C1-C5, C1-C4, C1-C3, C1-C2, C2 ⁇ C6, C2 ⁇ C5, C2 ⁇ C4, C2 ⁇ C3, C3 ⁇ C6, C3 ⁇ C5, C3 ⁇ C4, C4 ⁇ C6, C4 ⁇ C5 and C5 ⁇ C6 alkyl.
  • Secondary batteries also known as rechargeable batteries or storage batteries, refer to batteries that can be recharged to activate active materials and continue to be used after the battery is discharged.
  • active ions are embedded and detached back and forth between the positive and negative electrodes.
  • the isolation film is set between the positive and negative electrodes, which mainly prevents short circuit between the positive and negative electrodes. At the same time, Allows active ions to pass through.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer.
  • the positive electrode active material layer is usually made by coating the positive electrode slurry on the positive electrode current collector, drying and cold pressing.
  • the positive electrode slurry is usually made by coating the positive electrode active material, The conductive agent, binder and other components are dispersed in the solvent and stirred evenly.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer.
  • the negative electrode active material layer is usually made by coating the negative electrode slurry on the negative electrode current collector, drying and cold pressing.
  • the negative electrode slurry is usually made by coating the negative electrode active material, The conductive agent, binder and other components are dispersed in the solvent and stirred evenly.
  • Binder is one of the important auxiliary materials in secondary batteries. It has no capacity itself and accounts for a very small proportion in secondary batteries. However, it has a significant influence on the production process of electrode sheets and the electrochemical performance of secondary batteries. important influence. Binders are mainly used to bond components such as active materials and conductive agents to each other and to bond active materials and current collectors to enhance the electronic contact between active materials and conductive agents and the electrons between active materials and current collectors. contact, thereby reducing the internal resistance of the battery. In addition to having a bonding function, the binder also needs to be able to withstand the swelling of the electrolyte to ensure that the electrode sheet maintains good structural stability during the long-term charging and discharging process of the secondary battery. Powder falls off due to excessive swelling or dissolution in the electrolyte.
  • Binders can be divided into two types: water-based binders and oil-based binders.
  • the corresponding solvents used in preparing electrode slurries are deionized water and organic solvents, such as N-methylpyrrolidone (NMP).
  • NMP N-methylpyrrolidone
  • PVDF has the advantages of strong resistance to oxidation and reduction, good thermal stability and easy dispersion in NMP, it has become the best choice for cathode binders at present.
  • the current price of PVDF remains high, which increases the production cost of secondary batteries.
  • high-capacity cathode active materials need to be used.
  • PVDF has the defect that it is easy to remove HF in an alkaline environment and cause the cathode slurry to gel. Therefore, researchers are currently working on developing new fluorine-free binders to replace PVDF.
  • the commonly used fluorine-free binders for positive electrode plates mainly include copolymers of acrylonitrile and other monomers, such as acrylonitrile-acrylate copolymers.
  • the acrylonitrile segment has good electrolyte swelling resistance, but its bonding effect is not strong.
  • the acrylonitrile segment has a highly polar cyano group, which leads to the glass transition temperature of the binder. It is also relatively high and has poor molecular chain flexibility. Therefore, the flexibility of the binder is poor, which can easily lead to cracking and powder loss of the positive active material layer, affecting the electrochemical performance of the secondary battery.
  • the flexibility of the molecular chain of the binder can be improved to a certain extent, and the flexibility of the binder can be improved.
  • the acrylate monomer currently used is a short side chain acrylate monomer, which The polarity and solubility parameters of the carbonate solvent in the electrolyte are close to each other, which can easily cause the binder to swell too much in the electrolyte or even dissolve.
  • the inventor of the present application surprisingly discovered through extensive experimental research that by combining at least comonomers including acrylonitrile monomers, acrylic monomers, short side chain acrylate monomers and long side chain acrylate monomers After copolymerization, the obtained binder can have good flexibility, high adhesion and resistance to electrolyte swelling, and can therefore be used in positive electrode sheets.
  • the first aspect of the application provides a binder for a positive electrode sheet, including a copolymer formed from a comonomer, wherein the comonomer includes a first monomer, a second monomer, The third monomer and the fourth monomer, the first monomer includes one or more compounds represented by Formula 1, and the second monomer includes one or more compounds represented by Formula 2. species, the third monomer includes one or more compounds represented by Formula 3, and the fourth monomer includes one or more compounds represented by Formula 4.
  • R 11 to R 13 , R 21 to R 23 , R 31 to R 33 , and R 41 to R 43 each independently represent a hydrogen atom, a halogen atom, an acid halide group, a nitro group, or a cyano group.
  • R a carboxyl, hydroxyl, and at least one of the group consisting of the following groups substituted or unsubstituted by R a : C1 to C6 alkyl, C2 to C6 alkenyl, C1 to C6 alkoxy, C1 to C6 alkylthio group, C3 ⁇ C6 cycloalkyl, C3 ⁇ C6 heterocycloalkyl, R 14 represents C10 ⁇ C30 alkyl, C10 ⁇ C30 alkenyl substituted or unsubstituted by R a , R 24 represents substituted or unsubstituted by R a C1 ⁇ C9 alkyl group, C2 ⁇ C9 alkenyl group, R 34 represents a hydrogen atom, an alkali metal atom, a carboxyl substituted or unsubstituted C1 ⁇ C6 alkyl group, R a includes a halogen atom, an acid halide group, a nitro group, and a cyano group , one or more
  • the molar content of the first monomer is 3 mol% to 10 mol% based on the total molar amount of the comonomers being 100 mol%.
  • the inventor of the present application unexpectedly discovered during the research process that by copolymerizing comonomers including at least the above-mentioned first monomer, second monomer, third monomer and fourth monomer, the bonding obtained
  • the agent not only has good flexibility and high adhesion, but also has good electrolyte swelling resistance.
  • the first monomer represented by Formula 1 is an acrylate compound with a long side chain. Therefore, it has a certain crystallization behavior when forming a copolymer, thereby enabling the obtained bonding
  • the agent has appropriate crystallinity, and can also make the obtained binder have a smaller degree of swelling in the electrolyte; at the same time, the first monomer shown in Formula 1 has a longer molecular chain, which can also make The resulting adhesive has better flexibility.
  • the second monomer represented by Formula 2 is an acrylate compound with a short side chain, which contributes to the high adhesiveness of the obtained adhesive.
  • the third monomer shown in Formula 3 is an acrylic compound, which helps to make the obtained adhesive highly adhesive.
  • the fourth monomer shown in Formula 4 is an acrylonitrile monomer, which has a highly polar cyano functional group, so that the obtained binder has good electrolyte swelling resistance.
  • the binder provided by this application not only has good flexibility and high adhesion, but also has good electrolyte swelling resistance.
  • a first monomer unit with a similar structure to Formula 1 in the binder the difference from the first monomer is that the carbon-carbon double bond is opened during copolymerization
  • the electrolyte swelling resistance of the binder can be better improved and flexibility
  • a second monomer unit with a similar structure to Formula 2 in the binder the difference from the second monomer is that the carbon-carbon double bond is opened during copolymerization
  • the adhesiveness of the binder can be increased
  • a third monomer unit with a similar structure to formula 3 in the binder the difference from the third monomer is that the carbon-carbon double bond is opened during copolymerization
  • the adhesiveness of the binder can be increased and the binder can be improved Affinity with the positive electrode active material, conductive agent and positive electrode current collector
  • the adhesive provided in this application is an oily adhesive, which is insoluble in water and can replace the currently commonly used polyvinylidene fluoride adhesive.
  • the molar content of the first monomer is 3 mol% to 10 mol% based on the total molar amount of the comonomers being 100 mol%.
  • the molar content of the first monomer is in the range of 3 mol%, 4 mol%, 5 mol%, 6 mol%, 7 mol%, 8 mol%, 9 mol%, 10 mol% or any above value.
  • the molar content of the first monomer is 4 mol% to 10 mol%, 5 mol% to 10 mol%, 6 mol% to 10 mol%, 4 mol% to 9 mol%, 5 mol% to 9 mol% or 6 mol% to 9 mol%.
  • the binder When the molar content of the first monomer is within an appropriate range, it is beneficial for the binder to have good flexibility and resistance to electrolyte swelling.
  • the molar content of the first monomer When the molar content of the first monomer is greater than 10 mol%, the resulting binder cannot be dissolved in NMP, and the cathode slurry cannot be prepared; when the molar content of the first monomer is less than 3 mol%, it cannot achieve the desired effect. It improves the flexibility and electrolyte swelling resistance of the binder, and the resulting binder can even be dissolved in the electrolyte.
  • the molar content of the second monomer is from 1 mol% to 30 mol% based on a total molar amount of the comonomers of 100 mol%.
  • the molar content of the second monomer is 5 mol%, 8 mol%, 10 mol%, 12.5 mol%, 15 mol%, 17.5 mol%, 20 mol%, 22.5 mol%, 25 mol%, 27.5 mol%, 30 mol% or more. Any range of values.
  • the molar content of the second monomer is 5 mol% to 30 mol%, 8 mol% to 30 mol%, 12.5 mol% to 30 mol%, 12.5 mol% to 27.5 mol%, 12.5 mol% to 25 mol%, 12.5 mol % to 22.5mol% or 12.5mol% to 20mol%.
  • the molar content of the second monomer is within an appropriate range, it is beneficial for the binder to have better adhesion.
  • the molar content of the third monomer is from 1 mol% to 10 mol% based on a total molar amount of the comonomers of 100 mol%.
  • the molar content of the third monomer is in the range of 1 mol%, 2 mol%, 3 mol%, 4 mol%, 5 mol%, 6 mol%, 7 mol%, 8 mol%, 9 mol%, 10 mol% or any above value.
  • the molar content of the third monomer is 2 mol% to 10 mol%, 3 mol% to 10 mol%, 3 mol% to 9 mol%, or 3 mol% to 8 mol%.
  • the binder When the molar content of the third monomer is within an appropriate range, it is beneficial to the binder to have better adhesion and further improve the affinity between the binder and the cathode active material, conductive agent and cathode current collector. and sex.
  • the molar content of the fourth monomer is 50 mol% to 95 mol% based on a total molar amount of the comonomers of 100 mol%.
  • the molar content of the fourth monomer is 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, 75 mol%, 80 mol%, 84 mol%, 88 mol%, 92 mol%, 95 mol% or any above value. range.
  • the molar content of the fourth monomer is 50 mol% to 95 mol%, 55 mol% to 90 mol%, 60 mol% to 84 mol%, 65 mol% to 80 mol% or 70 mol% to 80 mol%.
  • the molar content of the first monomer is from 3 mol% to 10 mol%
  • the molar content of the second monomer is from 1 mol% to 100 mol%.
  • the molar content of the third monomer is 1 mol% to 10 mol%
  • the molar content of the fourth monomer is 50 mol% to 95 mol%. Therefore, the adhesive provided by this application can better balance flexibility, high adhesion and resistance to electrolyte swelling.
  • the molar content of the first monomer is 5 mol% to 9 mol%, and the molar content of the second monomer is 8 mol% to 100 mol%. 30 mol%, the molar content of the third monomer is 3 mol% to 10 mol%, and the molar content of the fourth monomer is 60 mol% to 84 mol%. Therefore, the adhesive provided by this application can better balance flexibility, high adhesion and resistance to electrolyte swelling.
  • the adhesive obtained at least includes a structure similar to Formula 1.
  • the first monomer unit with the same molar content, the second monomer unit with the same structure and the same molar content as the formula 2 the third monomer unit with the same structure as the formula 3 and the same molar content, the third monomer unit with the same structure as the formula 4 and the same molar content.
  • the fourth monomer unit has the same content.
  • R 11 to R 13 each independently represents a hydrogen atom, a halogen atom, an acid halide group, a nitro group, a cyano group, a carboxyl group, a C1 to C6 alkyl group, or a C1 to C6 haloalkyl group.
  • R 11 to R 13 all represent hydrogen atoms.
  • R 14 represents a C14-C22 alkyl group or a C14-C22 alkenyl group substituted or unsubstituted by R a .
  • R 14 represents a C14-C22 alkyl group or a C14-C22 alkenyl group substituted or unsubstituted by R a .
  • R 14 represents dodecyl, tetradecyl, hexadecyl, octadecyl, eicosanyl, behenyl, substituted or unsubstituted by R base.
  • the side chain R 14 represents an even number of carbon atoms, the binder is easier to crystallize, and the formed grains are more regular, which can improve the binder's resistance to electrolyte swelling, and the binder can also have better of flexibility.
  • the first monomer includes decyl acrylate, isodecyl acrylate, undecyl acrylate, dodecyl acrylate, tridecyl acrylate, tetradecyl acrylate ester, pentadecyl acrylate, cetyl acrylate, heptadecyl acrylate, stearyl acrylate, isostearyl acrylate, nonadecyl acrylate, 2-methyl acrylate Nonadecyl acrylate, eicosanyl acrylate, behenyl acrylate, behenyl acrylate, oleyl methacrylate, decyl methacrylate, isodecyl methacrylate, methacrylate Undecyl methacrylate, dodecyl methacrylate, 2-butyloctyl methacrylate, tridecyl methacrylate, myristyl methacrylate,
  • R 21 to R 23 each independently represents a hydrogen atom, a halogen atom, an acid halide group, a nitro group, a cyano group, a carboxyl group, a C1 to C6 alkyl group, or a C1 to C6 haloalkyl group.
  • R 21 to R 23 all represent hydrogen atoms.
  • the second monomer may include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, amyl acrylate, isopentyl acrylate Ester, hexyl acrylate, ethylhexyl acrylate, heptyl acrylate, octyl acrylate, isooctyl acrylate, nonyl acrylate, isononyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, methyl acrylate Methyl acrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, hydroxyethyl caprolactone methacrylate, butyl ester, isobutyl methacrylate, amyl methacrylate, amyl methacrylate
  • R 31 to R 33 each independently represents a hydrogen atom, a halogen atom, an acid halide group, a nitro group, a cyano group, a carboxyl group, a C1 to C6 alkyl group, or a C1 to C6 haloalkyl group.
  • R 31 to R 33 all represent hydrogen atoms.
  • the third monomer includes acrylic acid, itaconic acid, ⁇ -(acryloyloxy)propionic acid, maleic acid, fumaric acid, lithium acrylate, sodium acrylate, methacrylic acid, One or more of lithium methacrylate and sodium methacrylate, optionally including acrylic acid, itaconic acid, ⁇ -(acryloyloxy)propionic acid, maleic acid, fumaric acid, lithium acrylate, and sodium acrylate one or more of them.
  • R 41 to R 43 each independently represents a hydrogen atom, a halogen atom, an acid halide group, a nitro group, a cyano group, a carboxyl group, a C1 to C6 alkyl group, or a C1 to C6 haloalkyl group.
  • R 41 to R 43 all represent hydrogen atoms.
  • the fourth monomer includes acrylonitrile, methacrylonitrile, trifluoromethylacrylonitrile, ethacrylonitrile, 2-chloroacrylonitrile, 2-methyl-2-butan One or more acrylonitriles, optionally including acrylonitrile.
  • the comonomer may also include a small amount of a fifth monomer.
  • the fifth monomer may include an acrylamide monomer, an aliphatic monoolefin monomer, an aliphatic conjugated diamine monomer, or an aliphatic monoolefin monomer.
  • the acrylamide monomer includes one or more of acrylamide, methacrylamide, hydroxymethylacrylamide, and hydroxyethylacrylamide.
  • the aliphatic monoolefin monomer includes one or more of halogen-substituted or unsubstituted ethylene, propylene, and butylene.
  • the aliphatic conjugated diene hydrocarbon monomer includes one or more of halogen-substituted or unsubstituted butadiene and isoprene.
  • the binder may also include one or more of a dispersant, an initiator, and a chain transfer agent.
  • the dispersant may be an organic dispersant, optionally including one or more of polyvinyl alcohol, gelatin, carboxymethylcellulose, polyethylene glycol, and polyacrylate.
  • the initiator may be an oil-soluble initiator, optionally including one or more of azo initiators and organic peroxy initiators.
  • Azo initiators include but are not limited to one of azobisisobutyronitrile, azobisisoheptanitrile, azobisisovaleronitrile, azodicyclohexylcarbonitrile, and azobisisobutyric acid dimethyl ester.
  • Organic peroxygen initiators include but are not limited to dibenzoyl peroxide.
  • the chain transfer agent may include one or more of dodecyl mercaptan, cetyl mercaptan, and stearyl mercaptan.
  • the binder can be synthesized by suspension polymerization.
  • the binder has a weight average molecular weight of 100,000 to 1,000,000, optionally 100,000 to 500,000.
  • the weight average molecular weight of the binder is within a suitable range, it is beneficial for the binder to have good adhesion, and is also beneficial for the preparation of the positive electrode slurry, for example, preventing the slurry from being too viscous and not conducive to stirring.
  • the weight average molecular weight of the binder has a meaning known in the art, and can be measured using instruments and methods known in the art.
  • high performance liquid chromatography can be used for determination
  • Waters' e2695 high performance liquid chromatograph can be used for testing.
  • the glass transition temperature (Tg) of the binder is below 50°C, optionally 0°C to 50°C, more preferably 35°C to 50°C.
  • the binder has better flexibility and can effectively prevent the cathode active material layer from cracking and falling off.
  • the glass transition temperature of the binder has a well-known meaning in the art, and can be measured using instruments and methods well-known in the art. For example, you can refer to GB/T 29611-2013 for measurement, and the test can use Mettler-Toledo's DSC-3 differential scanning calorimeter.
  • the swelling degree of the adhesive when soaked in carbonate solvent in a 25° C. environment for 7 days is between 10% and 70%. In some embodiments, the swelling degree of the adhesive when soaked in carbonate solvent in a 60° C. environment for 3 days is between 15% and 100%.
  • the carbonate solvent is configured as follows: ethylene carbonate, dimethyl carbonate and diethyl carbonate are uniformly mixed at a mass ratio of 20:30:50.
  • the binder provided by this application has low solubility in the electrolyte, thereby enabling the positive electrode plate to maintain good structural stability during long-term charging and discharging processes.
  • the second aspect of this application provides a method for synthesizing the adhesive described in any embodiment of the first aspect of this application, including the following steps:
  • the comonomers include a first monomer, a second monomer, a third monomer and a fourth monomer, and the first monomer includes one of the compounds shown in Formula 1 or more, the second monomer includes one or more compounds represented by Formula 2, the third monomer includes one or more compounds represented by Formula 3, and the fourth monomer
  • the monomer includes one or more compounds represented by formula 4,
  • R 11 to R 13 , R 21 to R 23 , R 31 to R 33 , and R 41 to R 43 each independently represent a hydrogen atom, a halogen atom, an acid halide group, a nitro group, a cyano group, a carboxyl group, a hydroxyl group, and R a At least one of the group consisting of the following substituted or unsubstituted groups: C1 ⁇ C6 alkyl, C2 ⁇ C6 alkenyl, C1 ⁇ C6 alkoxy, C1 ⁇ C6 alkylthio, C3 ⁇ C6 cycloalkyl , C3 ⁇ C6 heterocycloalkyl group, R 14 represents C10 ⁇ C30 alkyl group, C10 ⁇ C30 alkenyl group substituted or unsubstituted by R a , R 24 represents C1 ⁇ C9 alkyl group, C2 substituted or unsubstituted by R a ⁇ C9 alkenyl group, R 34 represents a hydrogen atom
  • comonomer suspension polymerization Add dispersant and deionized water to the reaction kettle, pass inert gas below the liquid level of the reaction kettle, raise the temperature to the reaction temperature under stirring, and then add the comonomer under stirring.
  • the polymerization reaction is carried out using a polymer, an initiator and a chain transfer agent. After the reaction is completed, a polymer dispersion is obtained. The obtained polymer dispersion is then filtered, washed and dried to obtain the binder.
  • the binder can be synthesized through suspension polymerization, and the obtained binder has the advantage of narrow molecular weight distribution (for example, weight average molecular weight/number average molecular weight is 1 to 1.05).
  • the comonomer may also include a small amount of a fifth monomer, and the fifth monomer includes an acrylamide monomer, an aliphatic monoolefin monomer, and an aliphatic conjugated diene monomer. one or more of them.
  • the inert gas may be nitrogen.
  • the reaction temperature may be 65°C to 85°C.
  • the reaction time may be from 2 hours to 8 hours.
  • the stirring speed may be from 200 rpm to 400 rpm.
  • the dispersant may be an organic dispersant, optionally including one or more of polyvinyl alcohol, gelatin, carboxymethyl cellulose, polyethylene glycol, and polyacrylate.
  • the mass percentage of the dispersant is 0.1 to 2 wt% based on 100 wt% of the total mass of the comonomer.
  • the initiator may be an oil-soluble initiator, optionally including one or more of azo initiators and organic peroxy initiators.
  • Azo initiators include but are not limited to one of azobisisobutyronitrile, azobisisoheptanitrile, azobisisovaleronitrile, azodicyclohexylcarbonitrile, and azobisisobutyric acid dimethyl ester.
  • Organic peroxygen initiators include but are not limited to dibenzoyl peroxide.
  • the mass percentage of the initiator is 1 to 10 wt% based on 100 wt% of the total mass of the comonomers.
  • the chain transfer agent may include one or more of dodecyl mercaptan, cetyl mercaptan, and stearyl mercaptan.
  • the mass percentage of the chain transfer agent is 1 to 5 wt% based on 100 wt% of the total mass of the comonomers.
  • the synthesis method of the second aspect of the application can synthesize the adhesive of any embodiment of the first aspect of the application.
  • the adhesive of the first aspect of the application. agent which will not be described in detail here.
  • a third aspect of the present application provides a positive electrode sheet, including a positive current collector and a positive active material layer located on at least one surface of the positive current collector, wherein the positive active material layer includes the binder of the first aspect of the present application. Or a binder synthesized by the method of the second aspect of the present application.
  • the positive electrode current collector has two surfaces opposite in its thickness direction, and the positive electrode active material layer is provided on any one or both of the two opposite surfaces of the positive electrode current collector.
  • the binder provided by this application not only has good flexibility and high adhesion, but also has good electrolyte swelling resistance, thereby ensuring that the positive electrode plate has high bonding strength and good processing performance, while ensuring that the two
  • the secondary battery still has good structural stability during long-term charging and discharging, which is conducive to the full play of the electrochemical performance of the secondary battery.
  • the mass percentage of the binder is less than 5 wt%, optionally 1 to 3 wt%, based on the total mass of the cathode active material layer.
  • the cathode active material layer of the present application does not exclude other binders other than the binder of the first aspect of the present application or the binder synthesized by the method of the second aspect of the present application.
  • the bonding strength between the cathode active material layer and the cathode current collector is ⁇ 8 N/m.
  • the bonding strength between the positive active material layer and the positive current collector can be tested by the following method: Cut the positive electrode piece into a test sample with a width of 20mm and a length of 250mm, and take a strip with a width of 20mm and a length of 120mm.
  • Stainless steel plate use double-sided tape with a width of 20mm to paste the test sample on the stainless steel plate.
  • Use a pull A tensile testing machine is used to test the 180-degree peel strength, which is the bonding strength between the positive active material layer and the positive current collector.
  • the tensile speed of the tensile testing machine is 50mm/min.
  • the tensile testing machine can be the Instron 3365 tensile testing machine.
  • the positive active material layer includes a positive active material.
  • the positive active material may include, but is not limited to, one or more of lithium-containing transition metal oxides, lithium-containing phosphates and their respective modified compounds.
  • the lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt One or more of manganese oxide, lithium nickel cobalt aluminum oxide and their respective modified compounds.
  • lithium-containing phosphate may include, but are not limited to, lithium iron phosphate, composites of lithium iron phosphate and carbon, lithium manganese phosphate, composites of lithium manganese phosphate and carbon, lithium iron manganese phosphate, lithium iron manganese phosphate and carbon.
  • lithium iron phosphate composites of lithium iron phosphate and carbon
  • manganese phosphate composites of lithium manganese phosphate and carbon
  • iron manganese phosphate lithium iron manganese phosphate and carbon.
  • One or more of the composite materials and their respective modifying compounds are not limited to, lithium iron phosphate, composites of lithium iron phosphate and carbon.
  • the cathode active material for the lithium-ion battery may include a lithium transition metal oxide with the general formula Li a Ni b Co c M d O e Af and its One or more of the modifying compounds. 0.8 ⁇ a ⁇ 1.2, 0.5 ⁇ b ⁇ 1, 0 ⁇ c ⁇ 1, 0 ⁇ d ⁇ 1, 1 ⁇ e ⁇ 2, 0 ⁇ f ⁇ 1, M is selected from Mn, Al, Zr, Zn, Cu, Cr , one or more of Mg, Fe, V, Ti and B, A is selected from one or more of N, F, S and Cl.
  • cathode active materials for lithium ion batteries may include LiCoO 2 , LiNiO 2 , LiMnO 2 , LiMn 2 O 4 , LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM333), LiNi 0.5 Co 0.2 One of Mn 0.3 O 2 (NCM523), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), LiNi 0.85 Co 0.15 Al 0.05 O 2 , LiFePO 4 , LiMnPO 4 or more.
  • LiCoO 2 LiNiO 2 , LiMnO 2 , LiMn 2 O 4 , LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM333), LiNi 0.5 Co 0.2 One of Mn 0.3 O 2 (NCM523), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM81
  • the positive active material may include but is not limited to sodium-containing transition metal oxides, polyanionic materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.) , one or more Prussian blue materials.
  • cathode active materials for sodium ion batteries may include NaFeO 2 , NaCoO 2 , NaCrO 2 , NaMnO 2 , NaNiO 2 , NaNi 1/2 Ti 1/2 O 2 , NaNi 1/2 Mn 1/2 O 2 , Na 2/3 Fe 1/3 Mn 2/3 O 2 , NaNi 1/3 Co 1/3 Mn 1/3 O 2 , NaFePO 4 , NaMnPO 4 , NaCoPO 4 , Prussian blue materials, the general formula is X p M' q (PO 4 ) r O x Y 3-x one or more materials.
  • M' is a transition metal cation, optionally one of V, Ti, Mn, Fe, Co, Ni, Cu and Zn
  • Y is a halogen anion, optionally one or more of F, Cl and Br.
  • the modified compounds of each of the above-mentioned positive electrode active materials may be doping modifications and/or surface coating modifications of the positive electrode active materials.
  • the cathode active material layer may further include a cathode conductive agent.
  • a cathode conductive agent This application has no special limitation on the type of the positive electrode conductive agent.
  • the positive electrode conductive agent includes superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, and graphene. , one or more types of carbon nanofibers.
  • the mass percentage of the cathode conductive agent is ⁇ 5% based on the total mass of the cathode active material layer.
  • the positive electrode current collector may be a metal foil or a composite current collector.
  • a metal foil aluminum foil can be used.
  • the composite current collector may include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer.
  • the metallic material may include one or more of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys.
  • the polymer material base layer may include polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS) and One or more types of polyethylene (PE).
  • the positive electrode active material layer is usually formed by coating the positive electrode slurry on the positive electrode current collector, drying, and cold pressing.
  • the positive electrode slurry is usually formed by dispersing the positive electrode active material, binder, conductive agent and any other components in an organic solvent and stirring evenly.
  • the organic solvent may be N-methylpyrrolidone (NMP), but is not limited thereto.
  • the fourth aspect of the present application also provides a secondary battery, which includes the positive electrode plate of the third aspect of the present application.
  • the secondary battery may be a lithium-ion battery, a sodium-ion battery, etc.
  • the secondary battery may be a lithium-ion secondary battery.
  • the positive electrode sheet used in the secondary battery of the present application is the positive electrode sheet of any embodiment of the third aspect of the present application.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector and including a negative electrode active material.
  • the negative electrode current collector has two surfaces opposite in its thickness direction, and the negative electrode active material layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.
  • the negative active material may be a negative active material known in the art for secondary batteries.
  • the negative active material may include, but is not limited to, one or more of natural graphite, artificial graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate.
  • the silicon-based material may include one or more of elemental silicon, silicon oxide, silicon-carbon composite, silicon-nitride composite and silicon alloy material.
  • the tin-based material may include one or more of elemental tin, tin oxide and tin alloy materials.
  • the negative active material layer optionally further includes a negative conductive agent.
  • a negative conductive agent This application has no particular limitation on the type of the negative electrode conductive agent.
  • the negative electrode conductive agent may include superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphite One or more of ene and carbon nanofibers.
  • the mass percentage of the negative conductive agent is ⁇ 5%.
  • the negative active material layer optionally further includes a negative binder.
  • the negative electrode binder may include styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, water-based acrylic resin (for example, One of polyacrylic acid PAA, polymethacrylic acid PMAA, polyacrylic acid sodium PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA) and carboxymethyl chitosan (CMCS) or more.
  • SBR styrene-butadiene rubber
  • SR-1B water-soluble unsaturated resin
  • acrylic resin for example, One of polyacrylic acid PAA, polymethacrylic acid PMAA, polyacrylic acid sodium PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA) and carboxymethyl chitosan (CMCS) or more.
  • the mass percentage of the negative electrode binder is ⁇ 5% based on the total mass of the negative electrode active material
  • the negative active material layer optionally further includes other auxiliaries.
  • other auxiliaries may include thickeners such as sodium carboxymethyl cellulose (CMC), PTC thermistor materials, and the like.
  • CMC sodium carboxymethyl cellulose
  • PTC thermistor materials PTC thermistor materials, and the like.
  • the mass percentage of the other additives is ⁇ 2%.
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • the metal foil copper foil can be used.
  • the composite current collector may include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer.
  • the metal material may include one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys.
  • the polymer material base layer may include polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS) and One or more types of polyethylene (PE).
  • the negative active material layer is usually formed by coating the negative electrode slurry on the negative electrode current collector, drying, and cold pressing.
  • the negative electrode slurry is usually formed by dispersing the negative electrode active material, optional conductive agent, optional binder, and other optional additives in a solvent and stirring evenly.
  • the solvent may be N-methylpyrrolidone (NMP) or deionized water, but is not limited thereto.
  • the negative electrode plate does not exclude other additional functional layers in addition to the negative active material layer.
  • the negative electrode sheet described in the present application further includes a conductive undercoat layer (such as Composed of conductive agent and adhesive).
  • the negative electrode sheet described in this application further includes a protective layer covering the surface of the negative active material layer.
  • the electrolyte solution includes electrolyte salts and solvents.
  • the types of the electrolyte salt and the solvent are not specifically limited and can be selected according to actual needs.
  • the electrolyte salt may include but is not limited to lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium perchlorate (LiClO 4 ), hexafluoroborate Lithium fluoroarsenate (LiAsF 6 ), lithium bisfluorosulfonimide (LiFSI), lithium bistrifluoromethanesulfonimide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluoromethanesulfonate borate (LiDFOB) ), one or more of lithium difluoroborate (LiBOB), lithium difluorophosphate (LiPO 2 F 2 ), lithium difluorodioxalate phosphate (LiDFOP) and lithium tetrafluorooxalate phosphate (LiTF
  • the electrolyte salt may include but is not limited to sodium hexafluorophosphate (NaPF 6 ), sodium tetrafluoroborate (NaBF 4 ), sodium perchlorate (NaClO 4 ), sodium hexafluoromethanesulfonate (NaAsF 6 ), sodium bisfluorosulfonimide (NaFSI), sodium bistrifluoromethanesulfonimide (NaTFSI), sodium trifluoromethanesulfonate (NaTFS), difluoroxalic acid boric acid
  • NaDFOB sodium dioxaloborate
  • NaPO 2 F 2 sodium difluorodioxalophosphate
  • NaDFOP sodium tetrafluorooxalophosphate
  • NaTFOP sodium tetrafluorooxalophosphate
  • the solvent may include, but is not limited to, ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), Dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), One or more of ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS) and diethyl sul
  • additives are optionally included in the electrolyte.
  • the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain properties of the battery, such as additives that improve battery overcharge performance, additives that improve battery high-temperature performance, and additives that improve battery performance. Additives for low temperature power performance, etc.
  • the positive electrode piece, the isolation film and the negative electrode piece can be made into an electrode assembly through a winding process and/or a lamination process.
  • the secondary battery may include an outer packaging.
  • the outer packaging can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the secondary battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.
  • the outer packaging of the secondary battery may also be a soft bag, such as a bag-type soft bag.
  • the soft bag may be made of plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).
  • This application has no particular limitation on the shape of the secondary battery, which can be cylindrical, square or any other shape. As shown in FIG. 1 , a square-structured secondary battery 5 is shown as an example.
  • the outer package may include a housing 51 and a cover 53 .
  • the housing 51 may include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose to form a receiving cavity.
  • the housing 51 has an opening communicating with the accommodation cavity, and the cover plate 53 is used to cover the opening to close the accommodation cavity.
  • the positive electrode piece, the negative electrode piece and the isolation film can be formed into the electrode assembly 52 through a winding process and/or a lamination process.
  • the electrode assembly 52 is packaged in the containing cavity.
  • the electrolyte soaks into the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and can be adjusted according to needs.
  • the positive electrode sheet, the separator, the negative electrode sheet, and the electrolyte may be assembled to form a secondary battery.
  • the positive electrode sheet, isolation film, and negative electrode sheet can be formed into an electrode assembly through a winding process and/or a lamination process.
  • the electrode assembly is placed in an outer package, dried, and then injected with electrolyte. After vacuum packaging, static Through processes such as placement, formation, and shaping, secondary batteries are obtained.
  • the secondary batteries according to the present application can be assembled into a battery module.
  • the number of secondary batteries contained in the battery module can be multiple, and the specific number can be adjusted according to the application and capacity of the battery module.
  • FIG. 3 is a schematic diagram of the battery module 4 as an example.
  • a plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4 .
  • the plurality of secondary batteries 5 can be fixed by fasteners.
  • the battery module 4 may further include a housing having a receiving space in which a plurality of secondary batteries 5 are received.
  • the above-mentioned battery modules can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 arranged in the battery box.
  • the battery box includes an upper box 2 and a lower box 3 .
  • the upper box 2 is used to cover the lower box 3 and form a closed space for accommodating the battery module 4 .
  • Multiple battery modules 4 can be arranged in the battery box in any manner.
  • a fifth aspect of the present application provides an electrical device, which includes at least one of a secondary battery, a battery module or a battery pack of the present application.
  • the secondary battery, battery module or battery pack may be used as a power source for the electrical device or as an energy storage unit for the electrical device.
  • the electrical device may be, but is not limited to, mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric Golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • the power-consuming device can select a secondary battery, a battery module or a battery pack according to its usage requirements.
  • FIG. 6 is a schematic diagram of an electrical device as an example.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, etc.
  • battery packs or battery modules can be used.
  • the power-consuming device may be a mobile phone, a tablet computer, a laptop computer, etc.
  • the electrical device is usually required to be light and thin, and secondary batteries can be used as power sources.
  • the positive electrode sheets of Examples 1-10 and Comparative Examples 2-7 were prepared according to the following method.
  • the positive electrode active material NCM523, conductive agent carbon black, the above synthesized binder, and solvent NMP are fully stirred and mixed according to the weight ratio of 74:0.5:1.5:24 to obtain the positive electrode slurry; then the positive electrode slurry is evenly coated on The positive electrode current collector is placed on the aluminum foil, and then dried, cold pressed, and cut to obtain the positive electrode piece.
  • the positive electrode active material NCM523, conductive agent carbon black, binder polyvinylidene fluoride (PVDF), and solvent NMP are fully stirred and mixed at a weight ratio of 74:0.5:1.5:24 to obtain a positive electrode slurry; then the positive electrode slurry is It is evenly coated on the positive electrode current collector aluminum foil, and then dried, cold pressed, and cut to obtain the positive electrode piece.
  • PVDF binder polyvinylidene fluoride
  • the weight average molecular weight of the binder prepared above was tested by high performance liquid chromatography using a Waters e2695 high performance liquid chromatograph.
  • the Tg of the adhesive prepared above was tested using a Mettler-Toledo DSC-3 differential scanning calorimeter.
  • the test is carried out as follows: weigh about 10 mg of the binder sample into a flat-bottomed Al 2 O 3 crucible, shake it flat, cover it, and heat it from 35°C to 600°C at a rate of 10°C/min.
  • the protective gas is argon.
  • the purge gas flow is 50mL/min
  • the protective gas flow is 20mL/min.
  • the obtained binder was dispersed and dissolved in the solvent N-methylpyrrolidone (NMP) at high speed at 1500 rpm to prepare a solution with a mass concentration of 5wt%; the obtained solution was placed in a polytetrafluoroethylene petri dish Bake in a blast drying oven at 120°C for 4 hours to obtain a polymer film with a thickness of 0.1 mm to 1 mm.
  • NMP N-methylpyrrolidone
  • the carbonate solvent is configured as follows: ethylene carbonate, dimethyl carbonate and diethyl carbonate are uniformly mixed at a mass ratio of 20:30:50.
  • the adhesive obtained by copolymerizing the first monomer, the second monomer, the third monomer and the fourth monomer of the present application not only has a lower Tg and a high viscosity
  • the bonding strength is high, and it also has a small electrolyte swelling degree. Therefore, the binder provided by this application can replace the currently commonly used polyvinylidene fluoride binder.
  • Figure 7 is an infrared spectrum of the adhesive synthesized in Example 2.
  • the test instrument is a Thermo Fisher Nicolet iS10 Fourier transform infrared spectrometer.
  • the test standard is based on GB/T 6040-2019.
  • the adhesive synthesized in Example 2 has stretching vibration peaks of -CH 3 and -CH 2 near 2957cm -1 , 2927cm -1 and 2858cm -1 , and -C ⁇ near 2242cm -1

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

本申请提供一种用于正极极片的粘结剂及其合成方法、以及包含其的正极极片、二次电池及用电装置。所述粘结剂包括由共聚单体形成的共聚物，其中，所述共聚单体包括第一单体、第二单体、第三单体和第四单体，基于所述共聚单体的总摩尔量为100mol％计，所述第一单体的摩尔含量为3mol％至10mol％。本申请提供的粘结剂不仅具有良好的柔韧性和高粘结性，而且还具有良好的耐电解液溶胀特性，由此保证正极极片具有高粘结强度和良好的加工性能，同时保证二次电池长期充放电过程中仍具有良好的结构稳定性，进而有利于二次电池电化学性能的充分发挥。

Description

用于正极极片的粘结剂及其合成方法、以及包含其的正极极片、二次电池及用电装置 技术领域
本申请属于电池技术领域，具体涉及一种用于正极极片的粘结剂及其合成方法、以及包含其的正极极片、二次电池及用电装置。
背景技术
近年来，二次电池被广泛应用于水力、火力、风力和太阳能电站等储能电源系统，以及电动工具、电动自行车、电动摩托车、电动汽车、军事装备、航空航天等多个领域。目前，二次电池的正极极片采用的粘结剂仍以聚偏氟乙烯(PVDF)为主。随着二次电池的不断发展，市场对PVDF的需求也不断增加，由此导致了PVDF的价格居高不下，增加了二次电池的生产成本。此外，随着二次电池的容量越来越高，目前采用的正极活性材料表面残碱含量也变高，而PVDF在碱性环境下容易脱去HF并在分子链上形成一部分的碳碳双键，此时正极浆料的粘度会急剧增加，最终可能造成正极浆料凝胶化，导致正极浆料无法涂布。因此，有必要提供一种新型的无氟粘结剂，既可以降低生产成本，又能提高正极极片的粘结力。
发明内容
本申请的目的在于提供一种用于正极极片的粘结剂及其合成方法、以及包含其的正极极片、二次电池及用电装置，所述粘结剂不仅具有良好的柔韧性和高粘结性，而且还具有良好的耐电解液溶胀特性。
本申请第一方面提供一种用于正极极片的粘结剂，包括由共聚单体形成的共聚物，其中，所述共聚单体包括第一单体、第二单体、第三单体和第四单体，所述第一单体包括式1所示的化合物中的一种或多种，所述第二单体包括式2所示的化合物中的一种或多种，所述第三单体包括式3所示的化合物中的一种或多种，所述第四单体包括式4所示的化合物中的一种或多种，
Figure PCTCN2022104982-appb-000001
Figure PCTCN2022104982-appb-000002
R 11至R 13、R 21至R 23、R 31至R 33、R 41至R 43各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、羟基、以及被R a取代或未取代的如下基团组成的组中的至少一种：C1～C6烷基、C2～C6烯基、C1～C6烷氧基、C1～C6烷硫基、C3～C6环烷基、C3～C6杂环烷基，R 14表示被R a取代或未取代的C10～C30烷基、C10～C30烯基，R 24表示被R a取代或未取代的C1～C9烷基、C2～C9烯基，R 34表示氢原子、碱金属原子、羧基取代或未取代的C1～C6烷基，R a包括卤素原子、酰卤基、硝基、氰基、羧基、羟基中的一种或多种，基于所述共聚单体的总摩尔量为100mol％计，所述第一单体的摩尔含量为3mol％至10mol％，可选为5mol％至9mol％。
本申请提供的粘结剂不仅具有良好的柔韧性和高粘结性，而且还具有良好的耐电解液溶胀特性。通过在粘结剂中引入与式1结构类似的第一单体单元(与第一单体的区别在于碳碳双键在共聚时打开)能够更好地提升粘结剂的耐电解液溶胀特性和柔韧性；通过在粘结剂中引入与式2结构类似的第二单体单元(与第二单体的区别在于碳碳双键在共聚时打开)能够增加粘结剂的粘结性；通过在粘结剂中引入与式3结构类似的第三单体单元(与第三单体的区别在于碳碳双键在共聚时打开)能够增加粘结剂的粘结性并提高粘结剂与正极活性材料、导电剂以及正极集流体之间的亲和性；通过在粘结剂中引入与式4结构类似的第四单体单元(与第四单体的区别在于碳碳双键在共聚时打开)能够保证粘结剂具有良好的耐电解液溶胀特性。第一单体的摩尔含量在合适的范围内时，有利于粘结剂具有良好的柔韧性和耐电解液溶胀的特性。
在本申请的任意实施方式中，基于所述共聚单体的总摩尔量为100mol％计，所述第二单体的摩尔含量为1mol％至30mol％，可选为8mol％至30mol％。由此有利于粘结剂具有更好的粘结性。
在本申请的任意实施方式中，基于所述共聚单体的总摩尔量为100mol％计，所述第三单体的摩尔含量为1mol％至10mol％，可选为3mol％至10mol％。由此有利于粘结剂具有更好的粘结性，还有利于进一步提高粘结剂与正极活性材料、导电剂以及正极集流体之间的亲和性。
在本申请的任意实施方式中，基于所述共聚单体的总摩尔量为100mol％计，所述第 四单体的摩尔含量为50mol％至95mol％，可选为60mol％至84mol％。由此有利于粘结剂具有更好的耐电解液溶胀特性。
在本申请的任意实施方式中，R 11至R 13各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、C1～C6烷基、C1～C6卤代烷基，可选地，R 11至R 13均表示氢原子。
在本申请的任意实施方式中，R 21至R 23各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、C1～C6烷基、C1～C6卤代烷基，可选地，R 21至R 23均表示氢原子。
在本申请的任意实施方式中，R 31至R 33各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、C1～C6烷基、C1～C6卤代烷基，可选地，R 31至R 33均表示氢原子。
在本申请的任意实施方式中，R 41至R 43各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、C1～C6烷基、C1～C6卤代烷基，可选地，R 41至R 43均表示氢原子。
在本申请的任意实施方式中，R 14表示被R a取代或未取代的C14～C22烷基、C14～C22烯基，可选地表示被R a取代或未取代的十二烷基、十四烷基、十六烷基、十八烷基、二十烷基、二十二烷基。当侧链R 14表示偶数碳原子时，粘结剂更易结晶，并且所形成的晶粒也更规整，由此能够提高粘结剂的耐电解液溶胀特性，同时粘结剂还能具有更好的柔韧性。
在本申请的任意实施方式中，所述第一单体包括丙烯酸癸酯、丙烯酸异癸酯、丙烯酸十一烷基酯、丙烯酸十二烷基酯、丙烯酸十三烷基酯、丙烯酸十四烷基酯、丙烯酸十五烷基酯、丙烯酸十六烷基酯、丙烯酸十七烷基酯、丙烯酸十八烷基酯、丙烯酸异十八酯、丙烯酸十九烷基酯、丙烯酸-2-甲基十九烷基酯、丙烯酸二十烷基酯、丙烯酸二十一烷基酯、丙烯酸二十二烷基酯、油基甲基丙烯酸酯、甲基丙烯酸癸酯、甲基丙烯酸异癸酯、甲基丙烯酸十一烷基酯、甲基丙烯酸十二烷基酯、2-丁基辛基甲基丙烯酸酯、甲基丙烯酸十三烷基酯、甲基丙烯酸十四烷基酯、甲基丙烯酸十五烷基酯、甲基丙烯酸十六烷基酯、甲基丙烯酸十七烷基酯、甲基丙烯酸十八烷基酯、甲基丙烯酸十九烷基酯、甲基丙烯酸二十烷基酯、甲基丙烯酸二十一烷基酯、甲基丙烯酸二十二烷基酯中的一种或多种，可选地包括丙烯酸十二烷基酯、丙烯酸十四烷基酯、丙烯酸十六烷基酯、丙烯酸十八烷基酯、丙烯酸二十烷基酯、丙烯酸二十二烷基酯、油基甲基丙烯酸酯、甲基丙烯酸癸酯、甲基丙烯酸十二烷基酯、甲基丙烯酸十四烷基酯、甲基丙烯酸十六烷基酯、甲基丙烯酸十八烷基酯、甲基丙烯酸二十烷基酯、甲基丙烯酸二十二烷基酯中的一种或多种。
在本申请的任意实施方式中，所述第二单体包括丙烯酸甲酯、丙烯酸乙酯、丙烯酸丙酯、丙烯酸异丙酯、丙烯酸丁酯、丙烯酸异丁酯、丙烯酸戊酯、丙烯酸异戊酯、丙烯酸己酯、丙烯酸乙基己酯、丙烯酸庚酯、丙烯酸辛酯、丙烯酸异辛酯、丙烯酸壬酯、丙烯酸异壬酯、丙烯酸羟乙酯、丙烯酸羟丙酯、丙烯酸羟丁酯、甲基丙烯酸甲酯、甲基丙烯酸乙酯、甲基丙烯酸丙酯、甲基丙烯酸异丙酯、甲基丙烯酸丙烯酸羟乙基己内酯、丁酯、甲基丙烯酸异丁酯、甲基丙烯酸戊酯、甲基丙烯酸异戊酯、甲基丙烯酸己酯、甲基丙烯酸乙基己酯、甲基丙烯酸庚酯、甲基丙烯酸辛酯、甲基丙烯酸异辛酯、甲基丙烯酸壬酯、甲基丙烯酸异壬酯、甲基丙烯酸羟丙酯、甲基丙烯酸羟丁酯中的一种或多种，可选地包括丙烯酸甲酯、丙烯酸乙酯、丙烯酸丙酯、丙烯酸异丙酯、丙烯酸丁酯、丙烯酸异丁酯、丙烯酸戊酯、丙烯酸异戊酯、丙烯酸己酯、丙烯酸乙基己酯、丙烯酸庚酯、丙 烯酸辛酯、丙烯酸异辛酯、丙烯酸壬酯、丙烯酸异壬酯、丙烯酸羟乙酯、丙烯酸羟丙酯、丙烯酸羟丁酯中的一种或多种。
在本申请的任意实施方式中，所述第三单体包括丙烯酸、衣康酸、β-(丙烯酰氧)丙酸、马来酸、富马酸、丙烯酸锂、丙烯酸钠、甲基丙烯酸、甲基丙烯酸锂、甲基丙烯酸钠中的一种或多种，可选地包括丙烯酸、衣康酸、β-(丙烯酰氧)丙酸、马来酸、富马酸、丙烯酸锂、丙烯酸钠中的一种或多种。
在本申请的任意实施方式中，所述第四单体包括丙烯腈、甲基丙烯腈、三氟甲基丙烯腈、乙基丙烯腈、2-氯丙烯腈、2-甲基-2-丁烯腈中的一种或多种，可选地包括丙烯腈。
在本申请的任意实施方式中，所述共聚单体还包括第五单体，所述第五单体包括丙烯酰胺类单体、脂肪族单烯烃类单体、脂肪族共轭二烯烃类单体中的一种或多种。可选地，所述丙烯酰胺类单体包括丙烯酰胺、甲基丙烯酰胺、羟甲基丙烯酰胺、羟乙基丙烯酰胺中的一种或多种；可选地，所述脂肪族单烯烃类单体包括卤素取代或未取代的乙烯、丙烯、丁烯中的一种或多种；可选地，所述脂肪族共轭二烯烃类单体包括卤素取代或未取代的丁二烯、异戊二烯中的一种或多种。
在本申请的任意实施方式中，所述粘结剂还包括分散剂、引发剂、链转移剂中的一种或多种。可选地，所述分散剂为有机分散剂，更可选地包括聚乙烯醇、明胶、羧甲基纤维素、聚乙二醇、聚丙烯酸盐中的一种或多种；可选地，所述引发剂为油溶性引发剂，更可选地包括偶氮类引发剂和有机过氧类引发剂中的一种或多种；可选地，所述链转移剂包括十二烷基硫醇、十六烷基硫醇、十八烷基硫醇中的一种或多种。
在本申请的任意实施方式中，所述粘结剂的重均分子量为10万至100万，可选为10万至50万。由此有利于粘结剂具有良好的粘结性，同时还有利于正极浆料的制备。
本申请的任意实施方式中，所述粘结剂的玻璃化转变温度在50℃以下，可选为0℃至50℃。由此，粘结剂的柔韧性更好，能够有效防止正极活性材料层开裂、脱落。
在本申请的任意实施方式中，所述粘结剂在25℃环境中于碳酸酯溶剂中浸泡7天的溶胀度在10％至70％之间。
在本申请的任意实施方式中，所述粘结剂在60℃环境中于碳酸酯溶剂中浸泡3天的溶胀度在15％至100％之间。
所述碳酸酯溶剂按照如下方法配置：将碳酸乙烯酯、碳酸二甲酯和碳酸二乙酯按照质量比为20:30:50混合均匀得到。
本申请提供的粘结剂在电解液中具有较小的溶解度，由此能够使正极极片在长期充放电过程中仍保持良好的结构稳定性。
本申请第二方面提供一种用于合成本申请第一方面的粘结剂的方法，包括以下步骤：
S1，提供共聚单体：所述共聚单体包括第一单体、第二单体、第三单体和第四单体，所述第一单体包括式1所示的化合物中的一种或多种，所述第二单体包括式2所示的化合物中的一种或多种，所述第三单体包括式3所示的化合物中的一种或多种，所述第四单体包括式4所示的化合物中的一种或多种，
Figure PCTCN2022104982-appb-000003
R 11至R 13、R 21至R 23、R 31至R 33、R 41至R 43各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、羟基、以及被R a取代或未取代的如下基团组成的组中的至少一种：C1～C6烷基、C2～C6烯基、C1～C6烷氧基、C1～C6烷硫基、C3～C6环烷基、C3～C6杂环烷基，R 14表示被R a取代或未取代的C10～C30烷基、C10～C30烯基，R 24表示被R a取代或未取代的C1～C9烷基、C2～C9烯基，R 34表示氢原子、碱金属原子、羧基取代或未取代的C1～C6烷基，R a包括卤素原子、酰卤基、硝基、氰基、羧基、羟基中的一种或多种，基于所述共聚单体的总摩尔量为100mol％计，所述第一单体的摩尔含量为3mol％至10mol％，可选为5mol％至9mol％；
S2，共聚单体悬浮聚合：向反应釜中加入分散剂和去离子水，将惰性气体通入反应釜液面以下，在搅拌状态下升温至反应温度，然后在搅拌状态下加入所述共聚单体、引发剂和链转移剂进行聚合反应，反应结束后得到聚合物分散液，再将所获得的聚合物分散液经过滤、洗涤、干燥，得到所述粘结剂。
本申请可以通过悬浮聚合法合成粘结剂，所获得的粘结剂具有分子量分布窄的优势。
在本申请的任意实施方式中，所述共聚单体还包括第五单体，所述第五单体包括丙烯酰胺类单体、脂肪族单烯烃类单体、脂肪族共轭二烯烃类单体中的一种或多种。
在本申请的任意实施方式中，所述反应温度为65℃至85℃。
在本申请的任意实施方式中，所述反应时间为2小时至8小时。
在本申请的任意实施方式中，所述搅拌速度为200转/分钟至400转/分钟。
在本申请的任意实施方式中，所述分散剂为有机分散剂，可选地包括聚乙烯醇、明胶、羧甲基纤维素、聚乙二醇、聚丙烯酸盐中的一种或多种。
在本申请的任意实施方式中，所述引发剂为油溶性引发剂，可选地包括偶氮类引发剂和有机过氧类引发剂中的一种或多种。
在本申请的任意实施方式中，所述链转移剂包括十二烷基硫醇、十六烷基硫醇、十八烷基硫醇中的一种或多种。
在本申请的任意实施方式中，基于所述共聚单体的总质量为100wt％计，所述分散剂的质量百分含量为0.1wt％至2wt％。
在本申请的任意实施方式中，基于所述共聚单体的总质量为100wt％计，所述引发剂的质量百分含量为1wt％至10wt％。
在本申请的任意实施方式中，基于所述共聚单体的总质量为100wt％计，所述链转移剂的质量百分含量为1wt％至5wt％。
本申请第三方面提供一种正极极片，包括正极集流体以及位于所述正极集流体至少一个表面的正极活性材料层，其中，所述正极活性材料层包括本申请第一方面的粘结剂或通过本申请第二方面的方法合成的粘结剂。
在本申请的任意实施方式中，所述正极活性材料层与所述正极集流体之间的粘结强度为≥8N/m。
本申请第四方面提供一种二次电池，包括本申请第三方面的正极极片。
本申请第五方面提供一种用电装置，包括本申请第四方面的二次电池。
本申请提供的粘结剂不仅具有良好的柔韧性和高粘结性，而且还具有良好的耐电解液溶胀特性，由此保证正极极片具有高粘结强度和良好的加工性能，同时保证二次电池长期充放电过程中仍具有良好的结构稳定性，进而有利于二次电池电化学性能的充分发挥。本申请的用电装置包括本申请提供的二次电池，因而至少具有与所述二次电池相同的优势。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对本申请实施例中所需要使用的附图作简单地介绍。显而易见地，下面所描述的附图仅仅是本申请的一些实施方式，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
图1是本申请的二次电池的一实施方式的示意图。
图2是图1的二次电池的实施方式的分解示意图。
图3是本申请的电池模块的一实施方式的示意图。
图4是本申请的电池包的一实施方式的示意图。
图5是图4所示的电池包的实施方式的分解示意图。
图6是包含本申请的二次电池作为电源的用电装置的一实施方式的示意图。
图7是实施例2合成的粘结剂的红外光谱图。
在附图中，附图未必按照实际的比例绘制。附图标记说明如下：1电池包，2上箱体，3下箱体，4电池模块，5二次电池，51壳体，52电极组件，53盖板。
具体实施方式
以下，适当地参照附图详细说明具体公开了本申请的用于正极极片的粘结剂及其合成方法、以及包含其的正极极片、二次电池及用电装置的实施方式。但是会有省略不必要的详细说明的情况。例如，有省略对已众所周知的事项的详细说明、实际相同结构的重复说明的情况。这是为了避免以下的说明不必要地变得冗长，便于本领域技术人员的理解。此外，附图及以下说明是为了本领域技术人员充分理解本申请而提供的，并不旨在限定权利要求书所记载的主题。
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110的范围，理解为60-110和80-120的范围也是预料到的。此外，如果列出的最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。在本申请中，除非有其他说明，数值范围“a-b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案，并且这样的技术方案应被认为包含在本申请的公开内容中。
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合形成新的技术方案，并且这样的技术方案应被认为包含在本申请的公开内容中。
如果没有特别的说明，本申请的所有步骤可以顺序进行，也可以随机进行，优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，所述提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。
如果没有特别的说明，本申请所提到的“包括”和“包含”表示开放式，也可以是封闭式。例如，所述“包括”和“包含”可以表示还可以包括或包含没有列出的其他组分，也可以仅包括或包含列出的组分。
如果没有特别的说明，在本申请中，术语“或”是包括性的。举例来说，短语“A或B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B都为真(或存在)。
如果没有特别的说明，在本申请中，术语“第一”、“第二”、“第三”、“第四”等是用于区别不同对象，而不是用于描述特定顺序或主次关系。
在本申请中，术语“多个”、“多种”是指两个或两种以上。
在本说明书的各处，化合物的取代基以组或范围公开。明确地预期这种描述包括这些组和范围的成员的每一个单独的子组合。例如，明确地预期术语“C1～C6烷基”单独地公开C1、C2、C3、C4、C5、C6、C1～C6、C1～C5、C1～C4、C1～C3、C1～C2、C2～C6、 C2～C5、C2～C4、C2～C3、C3～C6、C3～C5、C3～C4、C4～C6、C4～C5和C5～C6烷基。
除非另有说明，本申请中使用的术语具有本领域技术人员通常所理解的公知含义。
除非另有说明，本申请中提到的各参数的数值可以用本领域常用的各种测试方法进行测定，例如，可以按照本申请提供的测试方法进行测定。
二次电池又称为充电电池或蓄电池，是指在电池放电后可通过充电的方式使活性材料激活而继续使用的电池。在电池充放电过程中，活性离子在正极极片和负极极片之间往返嵌入和脱出，隔离膜设置在正极极片和负极极片之间，主要起到防止正极和负极短路的作用，同时可以使活性离子通过。正极极片包括正极集流体和正极活性材料层，正极活性材料层通常是将正极浆料涂布在正极集流体上，经干燥、冷压而成的，正极浆料通常是将正极活性材料、导电剂、粘结剂等组分分散于溶剂中并搅拌均匀而形成的。负极极片包括负极集流体和负极活性材料层，负极活性材料层通常是将负极浆料涂布在负极集流体上，经干燥、冷压而成的，负极浆料通常是将负极活性材料、导电剂、粘结剂等组分分散于溶剂中并搅拌均匀而形成的。
粘结剂是二次电池中重要的辅助材料之一，其本身没有容量，在二次电池中所占的比重也很小，但是对电极片的生产工艺和二次电池的电化学性能却有着重要的影响。粘结剂主要用于将活性材料、导电剂等组分彼此粘结以及将活性材料与集流体粘结，以增强活性材料、导电剂之间的电子接触以及活性材料和集流体之间的电子接触，从而降低电池内阻。粘结剂除了具有需要具有粘结功能之外，还需要能够耐受电解液的溶胀，以保证电极片在二次电池长期充放电过程中仍保持良好的结构稳定性，不会由于粘结剂溶胀度过大或溶解于电解液中而出现掉粉现象。
粘结剂可以分为水性粘结剂和油性粘结剂两种，对应制备电极浆料时采用的溶剂分别为去离子水和有机溶剂，例如，N-甲基吡咯烷酮(NMP)。目前，制备正极浆料时通常采用NMP作为溶剂。由于PVDF具有抗氧化还原能力强、热稳定性好且易分散在NMP中的优势，因此成为目前正极粘结剂的最佳选择。但是，目前PVDF的价格居高不下，由此增加了二次电池的生产成本。同时，由于市场对二次电池能量密度的需求越来越高，因此需要采用高容量型正极活性材料，而高容量型正极活性材料(例如高镍三元材料)面临的一个问题是其表面残碱的含量更高。PVDF存在在碱性环境下容易脱去HF而引起正极浆料凝胶化的缺陷，因此，目前研究者们正致力于开发新型的无氟粘结剂以替代PVDF。
目前正极极片常用的无氟粘结剂主要包括丙烯腈与其他单体形成的共聚物，例如丙烯腈-丙烯酸酯共聚物。在共聚物中，丙烯腈链段具有良好耐电解液溶胀特性，但是其粘结效果不强，同时由于丙烯腈链段具有强极性的氰基，由此导致粘结剂的玻璃化转变温度还较高、分子链柔顺性较差，因此，粘结剂的柔韧性差，进而容易导致正极活性材料层开裂、掉粉，影响二次电池的电化学性能。将丙烯腈与丙烯酸酯共聚后，可以在一定程度上提升粘结剂分子链的柔顺性，改善粘结剂的柔韧性，但是目前采用的丙烯酸酯单体为短侧链丙烯酸酯单体，其与电解液中碳酸酯类溶剂的极性和溶解度参数接近，由此容易造成粘结剂在电解液中的溶胀度偏大，甚至出现溶解。
本申请的发明人经过大量实验研究惊奇发现，通过将至少包括丙烯腈类单体、丙烯酸类单体、短侧链丙烯酸酯类单体以及长侧链丙烯酸酯类单体在内的共聚单体共聚后， 所获得的粘结剂能够兼顾良好的柔韧性、高粘结性和耐电解液溶胀的特性，由此能够应用于正极极片中。
粘结剂
具体地，本申请第一方面提供了一种用于正极极片的粘结剂，包括由共聚单体形成的共聚物，其中，所述共聚单体包括第一单体、第二单体、第三单体和第四单体，所述第一单体包括式1所示的化合物中的一种或多种，所述第二单体包括式2所示的化合物中的一种或多种，所述第三单体包括式3所示的化合物中的一种或多种，所述第四单体包括式4所示的化合物中的一种或多种。
Figure PCTCN2022104982-appb-000004
在式1至式4中，R 11至R 13、R 21至R 23、R 31至R 33、R 41至R 43各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、羟基、以及被R a取代或未取代的如下基团组成的组中的至少一种：C1～C6烷基、C2～C6烯基、C1～C6烷氧基、C1～C6烷硫基、C3～C6环烷基、C3～C6杂环烷基，R 14表示被R a取代或未取代的C10～C30烷基、C10～C30烯基，R 24表示被R a取代或未取代的C1～C9烷基、C2～C9烯基，R 34表示氢原子、碱金属原子、羧基取代或未取代的C1～C6烷基，R a包括卤素原子、酰卤基、硝基、氰基、羧基、羟基中的一种或多种。
基于所述共聚单体的总摩尔量为100mol％计，所述第一单体的摩尔含量为3mol％至10mol％。
本申请的发明人在研究过程中意外发现，通过将至少包括上述第一单体、第二单体、第三单体和第四单体在内的共聚单体共聚后，所获得的粘结剂不仅具有良好的柔韧性和高粘结性，而且还具有良好的耐电解液溶胀特性。
在本申请的共聚单体中，式1所示的第一单体为具有长侧链的丙烯酸酯化合物，由此其在形成共聚物时具有一定的结晶行为，进而能使所获得的粘结剂具有合适的结晶度， 并且还能使所获得的粘结剂在电解液中具有较小的溶胀度；同时，式1所示的第一单体的分子链较长，由此还能使所获得的粘结剂具有更好的柔韧性。式2所示的第二单体为具有短侧链的丙烯酸酯化合物，其有助于使所获得的粘结剂具有高粘结性。式3所示的第三单体为丙烯酸类化合物，其有助于使所获得的粘结剂具有高粘结性，同时由于其侧链结构含有羧酸基或羧酸盐官能团，这些官能团可与正极集流体(例如铝箔)表面的羟基、正极活性材料表面的羟基和/或残碱、导电剂表面的羟基等形成氢键作用，由此还有助于提升粘结剂与正极活性材料、导电剂以及正极集流体之间的亲和性。式4所示的第四单体为丙烯腈类单体，其具有强极性的氰基官能团，由此能使所获得的粘结剂具有良好的耐电解液溶胀特性。
因此，本申请提供的粘结剂不仅具有良好的柔韧性和高粘结性，而且还具有良好的耐电解液溶胀特性。通过在粘结剂中引入与式1结构类似的第一单体单元(与第一单体的区别在于碳碳双键在共聚时打开)能够更好地提升粘结剂的耐电解液溶胀特性和柔韧性；通过在粘结剂中引入与式2结构类似的第二单体单元(与第二单体的区别在于碳碳双键在共聚时打开)能够增加粘结剂的粘结性；通过在粘结剂中引入与式3结构类似的第三单体单元(与第三单体的区别在于碳碳双键在共聚时打开)能够增加粘结剂的粘结性并提高粘结剂与正极活性材料、导电剂以及正极集流体之间的亲和性；通过在粘结剂中引入与式4结构类似的第四单体单元(与第四单体的区别在于碳碳双键在共聚时打开)能够保证粘结剂具有良好的耐电解液溶胀特性。
本申请提供的粘结剂为油性粘结剂，其不溶于水，可以替代目前常用的聚偏氟乙烯粘结剂。
基于所述共聚单体的总摩尔量为100mol％计，所述第一单体的摩尔含量为3mol％至10mol％。例如，所述第一单体的摩尔含量为3mol％，4mol％，5mol％，6mol％，7mol％，8mol％，9mol％，10mol％或以上任何数值所组成的范围。可选地，所述第一单体的摩尔含量为4mol％至10mol％，5mol％至10mol％，6mol％至10mol％，4mol％至9mol％，5mol％至9mol％或6mol％至9mol％。第一单体的摩尔含量在合适的范围内时，有利于粘结剂具有良好的柔韧性和耐电解液溶胀的特性。当第一单体的摩尔含量大于10mol％时，所得到的粘结剂在NMP中无法溶解，由此无法制备正极浆料；当第一单体的摩尔含量小于3mol％时，则不能起到提升粘结剂的柔韧性和耐电解液溶胀特性的作用，同时所得到的粘结剂甚至会溶于电解液中。
在一些实施例中，基于所述共聚单体的总摩尔量为100mol％计，所述第二单体的摩尔含量为1mol％至30mol％。例如，所述第二单体的摩尔含量为5mol％，8mol％，10mol％，12.5mol％，15mol％，17.5mol％，20mol％，22.5mol％，25mol％，27.5mol％，30mol％或以上任何数值所组成的范围。可选地，所述第二单体的摩尔含量为5mol％至30mol％，8mol％至30mol％，12.5mol％至30mol％，12.5mol％至27.5mol％，12.5mol％至25mol％，12.5mol％至22.5mol％或12.5mol％至20mol％。第二单体的摩尔含量在合适的范围内时，有利于粘结剂具有更好的粘结性。
在一些实施例中，基于所述共聚单体的总摩尔量为100mol％计，所述第三单体的摩尔含量为1mol％至10mol％。例如，所述第三单体的摩尔含量为1mol％，2mol％，3mol％，4mol％，5mol％，6mol％，7mol％，8mol％，9mol％，10mol％或以上任何数 值所组成的范围。可选地，所述第三单体的摩尔含量为2mol％至10mol％，3mol％至10mol％，3mol％至9mol％或3mol％至8mol％。第三单体的摩尔含量在合适的范围内时，有利于粘结剂具有更好的粘结性，还有利于进一步提高粘结剂与正极活性材料、导电剂以及正极集流体之间的亲和性。
在一些实施例中，基于所述共聚单体的总摩尔量为100mol％计，所述第四单体的摩尔含量为50mol％至95mol％。例如，所述第四单体的摩尔含量为50mol％，55mol％，60mol％，65mol％，70mol％，75mol％，80mol％，84mol％，88mol％，92mol％，95mol％或以上任何数值所组成的范围。可选地，所述第四单体的摩尔含量为50mol％至95mol％，55mol％至90mol％，60mol％至84mol％，65mol％至80mol％或70mol％至80mol％。第四单体的摩尔含量在合适的范围内时，有利于粘结剂具有更好的耐电解液溶胀特性。
在一些实施例中，基于所述共聚单体的总摩尔量为100mol％计，所述第一单体的摩尔含量为3mol％至10mol％，所述第二单体的摩尔含量为1mol％至30mol％，所述第三单体的摩尔含量为1mol％至10mol％，所述第四单体的摩尔含量为50mol％至95mol％。由此本申请提供的粘结剂能更好地兼顾柔韧性、高粘结性和耐电解液溶胀特性。
在一些实施例中，基于所述共聚单体的总摩尔量为100mol％计，所述第一单体的摩尔含量为5mol％至9mol％，所述第二单体的摩尔含量为8mol％至30mol％，所述第三单体的摩尔含量为3mol％至10mol％，所述第四单体的摩尔含量为60mol％至84mol％。由此本申请提供的粘结剂能更好地兼顾柔韧性、高粘结性和耐电解液溶胀特性。
本申请中，通过将至少包括上述第一单体、第二单体、第三单体和第四单体在内的共聚单体共聚后，所获得的粘结剂至少包括与式1结构类似且摩尔含量相同的第一单体单元、与式2结构类似且摩尔含量相同的第二单体单元、与式3结构类似且摩尔含量相同的第三单体单元、与式4结构类似且摩尔含量相同的第四单体单元。
在一些实施例中，R 11至R 13各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、C1～C6烷基、C1～C6卤代烷基，可选地，R 11至R 13均表示氢原子。
在一些实施例中，可选地，R 14表示被R a取代或未取代的C14～C22烷基、C14～C22烯基。侧链R 14中的碳原子数在合适的范围内时，粘结剂更易结晶，并且所形成的晶粒也更规整，由此能够提高粘结剂的耐电解液溶胀特性，同时粘结剂还能具有更好的柔韧性。
在一些实施例中，可选地，R 14表示被R a取代或未取代的十二烷基、十四烷基、十六烷基、十八烷基、二十烷基、二十二烷基。当侧链R 14表示偶数碳原子时，粘结剂更易结晶，并且所形成的晶粒也更规整，由此能够提高粘结剂的耐电解液溶胀特性，同时粘结剂还能具有更好的柔韧性。
作为示例，在一些实施例中，所述第一单体包括丙烯酸癸酯、丙烯酸异癸酯、丙烯酸十一烷基酯、丙烯酸十二烷基酯、丙烯酸十三烷基酯、丙烯酸十四烷基酯、丙烯酸十五烷基酯、丙烯酸十六烷基酯、丙烯酸十七烷基酯、丙烯酸十八烷基酯、丙烯酸异十八酯、丙烯酸十九烷基酯、丙烯酸-2-甲基十九烷基酯、丙烯酸二十烷基酯、丙烯酸二十一烷基酯、丙烯酸二十二烷基酯、油基甲基丙烯酸酯、甲基丙烯酸癸酯、甲基丙烯酸异癸酯、甲基丙烯酸十一烷基酯、甲基丙烯酸十二烷基酯、2-丁基辛基甲基丙烯酸酯、甲基丙烯酸十三烷基酯、甲基丙烯酸十四烷基酯、甲基丙烯酸十五烷基酯、甲基丙烯酸十六烷 基酯、甲基丙烯酸十七烷基酯、甲基丙烯酸十八烷基酯、甲基丙烯酸十九烷基酯、甲基丙烯酸二十烷基酯、甲基丙烯酸二十一烷基酯、甲基丙烯酸二十二烷基酯中的一种或多种，可选地包括丙烯酸十二烷基酯、丙烯酸十四烷基酯、丙烯酸十六烷基酯、丙烯酸十八烷基酯、丙烯酸二十烷基酯、丙烯酸二十二烷基酯、油基甲基丙烯酸酯、甲基丙烯酸癸酯、甲基丙烯酸十二烷基酯、甲基丙烯酸十四烷基酯、甲基丙烯酸十六烷基酯、甲基丙烯酸十八烷基酯、甲基丙烯酸二十烷基酯、甲基丙烯酸二十二烷基酯中的一种或多种，更可选地包括丙烯酸十二烷基酯、丙烯酸十四烷基酯、丙烯酸十六烷基酯、丙烯酸十八烷基酯、丙烯酸二十烷基酯、丙烯酸二十二烷基酯中的一种或多种。
在一些实施例中，R 21至R 23各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、C1～C6烷基、C1～C6卤代烷基，可选地，R 21至R 23均表示氢原子。
作为示例，在一些实施例中，所述第二单体可以包括丙烯酸甲酯、丙烯酸乙酯、丙烯酸丙酯、丙烯酸异丙酯、丙烯酸丁酯、丙烯酸异丁酯、丙烯酸戊酯、丙烯酸异戊酯、丙烯酸己酯、丙烯酸乙基己酯、丙烯酸庚酯、丙烯酸辛酯、丙烯酸异辛酯、丙烯酸壬酯、丙烯酸异壬酯、丙烯酸羟乙酯、丙烯酸羟丙酯、丙烯酸羟丁酯、甲基丙烯酸甲酯、甲基丙烯酸乙酯、甲基丙烯酸丙酯、甲基丙烯酸异丙酯、甲基丙烯酸丙烯酸羟乙基己内酯、丁酯、甲基丙烯酸异丁酯、甲基丙烯酸戊酯、甲基丙烯酸异戊酯、甲基丙烯酸己酯、甲基丙烯酸乙基己酯、甲基丙烯酸庚酯、甲基丙烯酸辛酯、甲基丙烯酸异辛酯、甲基丙烯酸壬酯、甲基丙烯酸异壬酯、甲基丙烯酸羟丙酯、甲基丙烯酸羟丁酯中的一种或多种，可选地包括丙烯酸甲酯、丙烯酸乙酯、丙烯酸丙酯、丙烯酸异丙酯、丙烯酸丁酯、丙烯酸异丁酯、丙烯酸戊酯、丙烯酸异戊酯、丙烯酸己酯、丙烯酸乙基己酯、丙烯酸庚酯、丙烯酸辛酯、丙烯酸异辛酯、丙烯酸壬酯、丙烯酸异壬酯、丙烯酸羟乙酯、丙烯酸羟丙酯、丙烯酸羟丁酯中的一种或多种。
在一些实施例中，R 31至R 33各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、C1～C6烷基、C1～C6卤代烷基，可选地，R 31至R 33均表示氢原子。
作为示例，在一些实施例中，所述第三单体包括丙烯酸、衣康酸、β-(丙烯酰氧)丙酸、马来酸、富马酸、丙烯酸锂、丙烯酸钠、甲基丙烯酸、甲基丙烯酸锂、甲基丙烯酸钠中的一种或多种，可选地包括丙烯酸、衣康酸、β-(丙烯酰氧)丙酸、马来酸、富马酸、丙烯酸锂、丙烯酸钠中的一种或多种。
在一些实施例中，R 41至R 43各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、C1～C6烷基、C1～C6卤代烷基，可选地，R 41至R 43均表示氢原子。
作为示例，在一些实施例中，所述第四单体包括丙烯腈、甲基丙烯腈、三氟甲基丙烯腈、乙基丙烯腈、2-氯丙烯腈、2-甲基-2-丁烯腈中的一种或多种，可选地包括丙烯腈。
在一些实施例中，所述共聚单体还可以包括少量的第五单体，例如，所述第五单体可以包括丙烯酰胺类单体、脂肪族单烯烃类单体、脂肪族共轭二烯烃类单体中的一种或多种。可选地，所述丙烯酰胺类单体包括丙烯酰胺、甲基丙烯酰胺、羟甲基丙烯酰胺、羟乙基丙烯酰胺中的一种或多种。可选地，所述脂肪族单烯烃类单体包括卤素取代或未取代的乙烯、丙烯、丁烯中的一种或多种。可选地，所述脂肪族共轭二烯烃类单体包括卤素取代或未取代的丁二烯、异戊二烯中的一种或多种。
在一些实施例中，所述粘结剂还可以包括分散剂、引发剂、链转移剂中的一种或多种。
所述分散剂可以为有机分散剂，可选地包括聚乙烯醇、明胶、羧甲基纤维素、聚乙二醇、聚丙烯酸盐中的一种或多种。
所述引发剂可以为油溶性引发剂，可选地包括偶氮类引发剂和有机过氧类引发剂中的一种或多种。偶氮类引发剂包括但不限于偶氮二异丁腈、偶氮二异庚腈、偶氮二异戊腈、偶氮二环己基甲腈、偶氮二异丁酸二甲酯中的一种或多种。有机过氧类引发剂包括但不限于过氧化二苯甲酰。
所述链转移剂可以包括十二烷基硫醇、十六烷基硫醇、十八烷基硫醇中的一种或多种。
在一些实施例中，所述粘结剂可以通过悬浮聚合法合成。
在一些实施例中，所述粘结剂的重均分子量为10万至100万，可选为10万至50万。粘结剂的重均分子量在合适的范围内时，有利于粘结剂具有良好的粘结性，同时还有利于正极浆料的制备，例如防止浆料粘度过大而不利于搅拌。
在本申请中，粘结剂的重均分子量为本领域公知的含义，可以用本领域公知的仪器及方法进行测定。例如可以采用高效液相色谱法进行测定，测试可采用沃特世(Waters)的e2695型高效液相色谱仪。
在一些实施例中，所述粘结剂的玻璃化转变温度(Tg)在50℃以下，可选为0℃至50℃，更可选为35℃至50℃。粘结剂的玻璃化转变温度在合适的范围内时，粘结剂的柔韧性更好，能够有效防止正极活性材料层开裂、脱落。
在本申请中，粘结剂的玻璃化转变温度为本领域公知的含义，可以用本领域公知的仪器及方法进行测定。例如可以参考GB/T 29611-2013进行测定，测试可采用梅特勒-托利多(Mettler-Toledo)的DSC-3型差示扫描量热仪。
在一些实施例中，所述粘结剂在25℃环境中于碳酸酯溶剂中浸泡7天的溶胀度在10％至70％之间。在一些实施例中，所述粘结剂在60℃环境中于碳酸酯溶剂中浸泡3天的溶胀度在15％至100％之间。所述碳酸酯溶剂按照如下方法配置：将碳酸乙烯酯、碳酸二甲酯和碳酸二乙酯按照质量比为20:30:50混合均匀得到。本申请提供的粘结剂在电解液中具有较小的溶解度，由此能够使正极极片在长期充放电过程中仍保持良好的结构稳定性。
所述粘结剂的溶胀度可以通过如下测试方法获得：将粘结剂溶解于溶剂N-甲基吡咯烷酮中，配制成质量浓度为5wt％的溶液；将所获得的溶液置于聚四氟乙烯培养皿中在干燥箱中于120℃烘烤4小时获得具有一定厚度(例如0.1mm～1mm)的聚合物膜；将所获得的聚合物膜浸泡在预定温度的碳酸酯溶剂中，达到预定时间后取出，并根据公式计算溶胀度：溶胀度＝(浸泡后的质量－浸泡前的质量)/浸泡前的质量×100％。
合成方法
本申请第二方面提供一种用于合成本申请第一方面任一实施例所述的粘结剂的方法，包括以下步骤：
S1，提供共聚单体：所述共聚单体包括第一单体、第二单体、第三单体和第四单体，所述第一单体包括式1所示的化合物中的一种或多种，所述第二单体包括式2所示的化合 物中的一种或多种，所述第三单体包括式3所示的化合物中的一种或多种，所述第四单体包括式4所示的化合物中的一种或多种，
Figure PCTCN2022104982-appb-000005
R 11至R 13、R 21至R 23、R 31至R 33、R 41至R 43各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、羟基、以及被R a取代或未取代的如下基团组成的组中的至少一种：C1～C6烷基、C2～C6烯基、C1～C6烷氧基、C1～C6烷硫基、C3～C6环烷基、C3～C6杂环烷基，R 14表示被R a取代或未取代的C10～C30烷基、C10～C30烯基，R 24表示被R a取代或未取代的C1～C9烷基、C2～C9烯基，R 34表示氢原子、碱金属原子、羧基取代或未取代的C1～C6烷基，R a包括卤素原子、酰卤基、硝基、氰基、羧基、羟基中的一种或多种，基于所述共聚单体的总摩尔量为100mol％计，所述第一单体的摩尔含量为3mol％至10mol％，可选为5mol％至9mol％；
S2，共聚单体悬浮聚合：向反应釜中加入分散剂和去离子水，将惰性气体通入反应釜液面以下，在搅拌状态下升温至反应温度，然后在搅拌状态下加入所述共聚单体、引发剂和链转移剂进行聚合反应，反应结束后得到聚合物分散液，再将所获得的聚合物分散液经过滤、洗涤、干燥，得到所述粘结剂。
本申请可以通过悬浮聚合法合成粘结剂，所获得的粘结剂具有分子量分布窄(例如重均分子量/数均分子量为1～1.05)的优势。
在一些实施例中，所述共聚单体还可以包括少量第五单体，所述第五单体包括丙烯酰胺类单体、脂肪族单烯烃类单体、脂肪族共轭二烯烃类单体中的一种或多种。
在一些实施例中，所述惰性气体可以为氮气。
在一些实施例中，所述反应温度可以为65℃至85℃。
在一些实施例中，所述反应时间可以为2小时至8小时。
在一些实施例中，所述搅拌速度可以为200转/分钟至400转/分钟。
在一些实施例中，所述分散剂可以为有机分散剂，可选地包括聚乙烯醇、明胶、羧甲基纤维素、聚乙二醇、聚丙烯酸盐中的一种或多种。
在一些实施例中，基于所述共聚单体的总质量为100wt％计，所述分散剂的质量百分含量为0.1wt％至2wt％。
在一些实施例中，所述引发剂可以为油溶性引发剂，可选地包括偶氮类引发剂和有机过氧类引发剂中的一种或多种。偶氮类引发剂包括但不限于偶氮二异丁腈、偶氮二异庚腈、偶氮二异戊腈、偶氮二环己基甲腈、偶氮二异丁酸二甲酯中的一种或多种。有机过氧类引发剂包括但不限于过氧化二苯甲酰。
在一些实施例中，基于所述共聚单体的总质量为100wt％计，所述引发剂的质量百分含量为1wt％至10wt％。
在一些实施例中，所述链转移剂可以包括十二烷基硫醇、十六烷基硫醇、十八烷基硫醇中的一种或多种。
在一些实施例中，基于所述共聚单体的总质量为100wt％计，所述链转移剂的质量百分含量为1wt％至5wt％。
本申请第二方面的合成方法能够合成本申请第一方面任一实施例的粘结剂，在合成过程中所使用的各原料的具体种类及其具体含量可参考本申请第一方面的粘结剂，此处不再赘述。
正极极片
本申请第三方面提供一种正极极片，包括正极集流体以及位于所述正极集流体至少一个表面的正极活性材料层，其中，所述正极活性材料层包括本申请第一方面的粘结剂或通过本申请第二方面的方法合成的粘结剂。所述正极集流体具有在自身厚度方向相对的两个表面，所述正极活性材料层设置在所述正极集流体的两个相对表面中的任意一者或两者上。
本申请提供的粘结剂不仅具有良好的柔韧性和高粘结性，而且还具有良好的耐电解液溶胀特性，由此保证正极极片具有高粘结强度和良好的加工性能，同时保证二次电池长期充放电过程中仍具有良好的结构稳定性，进而有利于二次电池电化学性能的充分发挥。
在一些实施例中，基于所述正极活性材料层的总质量，所述粘结剂的质量百分含量在5wt％以下，可选地为1wt％至3wt％。
本申请的正极活性材料层并不排除除了本申请第一方面的粘结剂或通过本申请第二方面的方法合成的粘结剂以外的其他粘结剂。
在一些实施例中，所述正极活性材料层与所述正极集流体之间的粘结强度为≥8N/m。
正极活性材料层与正极集流体之间的粘结强度可以通过如下方法进行测试：将正极极片裁切成宽度为20mm、长度为250mm的测试样条，取一条宽度为20mm、长度为120mm的不锈钢板，用宽度为20mm的双面胶带将测试样条粘贴在不锈钢板上，粘贴时正极极片与不锈钢板的一端对齐，另一端预留出长度为130mm的正极极片作为延伸，采用拉伸试验机测试180度剥离强度，作为正极活性材料层与正极集流体之间的粘结强度，拉伸试验机的拉伸速度为50mm/min。拉伸试验机可以采用英斯特朗公司的3365型拉伸试验机。
所述正极活性材料层包括正极活性材料。
当本申请的二次电池为锂离子电池时，所述正极活性材料可包括但不限于含锂过渡金属氧化物、含锂磷酸盐及其各自的改性化合物中的一种或多种。所述锂过渡金属氧化物的示例可包括但不限于锂钴氧化物、锂镍氧化物、锂锰氧化物、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物、锂镍钴铝氧化物及其各自的改性化合物中的一种或多种。所述含锂磷酸盐的示例可包括但不限于磷酸铁锂、磷酸铁锂与碳的复合材料、磷酸锰锂、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料及其各自的改性化合物中的一种或多种。
在一些实施例中，为了进一步提高二次电池的能量密度，用于锂离子电池的正极活性材料可以包括通式为Li aNi bCo cM dO eA f的锂过渡金属氧化物及其改性化合物中的一种或多种。0.8≤a≤1.2，0.5≤b＜1，0＜c＜1，0＜d＜1，1≤e≤2，0≤f≤1，M选自Mn、Al、Zr、Zn、Cu、Cr、Mg、Fe、V、Ti和B中的一种或多种，A选自N、F、S和Cl中的一种或多种。
作为示例，用于锂离子电池的正极活性材料可包括LiCoO 2、LiNiO 2、LiMnO 2、LiMn 2O 4、LiNi 1/3Co 1/3Mn 1/3O 2(NCM333)、LiNi 0.5Co 0.2Mn 0.3O 2(NCM523)、LiNi 0.6Co 0.2Mn 0.2O 2(NCM622)、LiNi 0.8Co 0.1Mn 0.1O 2(NCM811)、LiNi 0.85Co 0.15Al 0.05O 2、LiFePO 4、LiMnPO 4中的一种或多种。
当本申请的二次电池为钠离子电池时，所述正极活性材料可包括但不限于含钠过渡金属氧化物、聚阴离子材料(如磷酸盐、氟磷酸盐、焦磷酸盐、硫酸盐等)、普鲁士蓝类材料中的一种或多种。
作为示例，用于钠离子电池的正极活性材料可包括NaFeO 2、NaCoO 2、NaCrO 2、NaMnO 2、NaNiO 2、NaNi 1/2Ti 1/2O 2、NaNi 1/2Mn 1/2O 2、Na 2/3Fe 1/3Mn 2/3O 2、NaNi 1/3Co 1/3Mn 1/3O 2、NaFePO 4、NaMnPO 4、NaCoPO 4、普鲁士蓝类材料、通式为X pM’ q(PO 4) rO xY 3-x的材料中的一种或多种。在通式X pM’ q(PO 4) rO xY 3-x中，0＜p≤4，0＜q≤2，1≤r≤3，0≤x≤2，X选自H +、Li +、Na +、K +和NH 4 +中的一种或多种，M’为过渡金属阳离子，可选地为V、Ti、Mn、Fe、Co、Ni、Cu和Zn中的一种或多种，Y为卤素阴离子，可选地为F、Cl和Br中的一种或多种。
在本申请中，上述各正极活性材料的改性化合物可以是对所述正极活性材料进行掺杂改性和/或表面包覆改性。
在一些实施例中，所述正极活性材料层还可以包括正极导电剂。本申请对所述正极导电剂的种类没有特别的限制，作为示例，所述正极导电剂包括超导碳、导电石墨、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯、碳纳米纤维中的一种或多种。在一些实施例中，基于所述正极活性材料层的总质量，所述正极导电剂的质量百分含量为≤5％。
在一些实施例中，所述正极集流体可采用金属箔片或复合集流体。作为金属箔片的示例，可采用铝箔。所述复合集流体可包括高分子材料基层以及形成于所述高分子材料基层至少一个表面上的金属材料层。作为示例，所述金属材料可包括铝、铝合金、镍、镍合金、钛、钛合金、银和银合金中的一种或多种。作为示例，所述高分子材料基层可包括聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)和聚乙烯(PE)中的一种或多种。
所述正极活性材料层通常是将正极浆料涂布在正极集流体上，经干燥、冷压而成的。所述正极浆料通常是将正极活性材料、粘结剂、导电剂以及任意的其他组分分散于有机溶剂中并搅拌均匀而形成的。有机溶剂可以是N-甲基吡咯烷酮(NMP)，但不限于此。
二次电池
本申请第四方面还提供了一种二次电池，其包括本申请第三方面的正极极片。
本申请对二次电池种类没有特别的限制，例如，所述二次电池可以为锂离子电池、钠离子电池等，特别地，所述二次电池可以为锂离子二次电池。
[正极极片]
本申请的二次电池中使用的正极极片为本申请第三方面任一实施例的正极极片。
[负极极片]
在一些实施例中，所述负极极片包括负极集流体以及设置在所述负极集流体至少一个表面且包括负极活性材料的负极活性材料层。例如，所述负极集流体具有在自身厚度方向相对的两个表面，所述负极活性材料层设置在所述负极集流体的两个相对表面中的任意一者或两者上。
所述负极活性材料可采用本领域公知的用于二次电池的负极活性材料。作为示例，所述负极活性材料可包括但不限于天然石墨、人造石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂中的一种或多种。所述硅基材料可包括单质硅、硅氧化物、硅碳复合物、硅氮复合物和硅合金材料中的一种或多种。所述锡基材料可包括单质锡、锡氧化物和锡合金材料中的一种或多种。
在一些实施例中，所述负极活性材料层还可选地包括负极导电剂。本申请对所述负极导电剂的种类没有特别的限制，作为示例，所述负极导电剂可包括超导碳、导电石墨、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯和碳纳米纤维中的一种或多种。在一些实施例中，基于所述负极活性材料层的总质量，所述负极导电剂的质量百分含量为≤5％。
在一些实施例中，所述负极活性材料层还可选地包括负极粘结剂。本申请对所述负极粘结剂的种类没有特别的限制，作为示例，所述负极粘结剂可包括丁苯橡胶(SBR)、水溶性不饱和树脂SR-1B、水性丙烯酸类树脂(例如，聚丙烯酸PAA、聚甲基丙烯酸PMAA、聚丙烯酸钠PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)和羧甲基壳聚糖(CMCS)中的一种或多种。在一些实施例中，基于所述负极活性材料层的总质量，所述负极粘结剂的质量百分含量为≤5％。
在一些实施例中，所述负极活性材料层还可选地包括其他助剂。作为示例，其他助剂可包括增稠剂，例如，羧甲基纤维素钠(CMC)、PTC热敏电阻材料等。在一些实施例中，基于所述负极活性材料层的总质量，所述其他助剂的质量百分含量为≤2％。
在一些实施例中，所述负极集流体可采用金属箔片或复合集流体。作为金属箔片的示例，可采用铜箔。所述复合集流体可包括高分子材料基层以及形成于所述高分子材料基层至少一个表面上的金属材料层。作为示例，所述金属材料可包括铜、铜合金、镍、镍合金、钛、钛合金、银和银合金中的一种或多种。作为示例，所述高分子材料基层可包括聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)和聚乙烯(PE)中的一种或多种。
所述负极活性材料层通常是将负极浆料涂布在负极集流体上，经干燥、冷压而成的。所述负极浆料通常是将负极活性材料、可选的导电剂、可选地粘结剂、其他可选的助剂分散于溶剂中并搅拌均匀而形成的。溶剂可以是N-甲基吡咯烷酮(NMP)或去离子水，但不限于此。
所述负极极片并不排除除了所述负极活性材料层之外的其他附加功能层。例如在某些实施例中，本申请所述的负极极片还包括夹在所述负极集流体和所述负极活性材料层之间、设置在所述负极集流体表面的导电底涂层(例如由导电剂和粘结剂组成)。在另外一些实施例中，本申请所述的负极极片还包括覆盖在所述负极活性材料层表面的保护层。
[电解液]
在二次电池充放电过程中，活性离子在所述正极极片和所述负极极片之间往返嵌入和脱出，所述电解液在所述正极极片和所述负极极片之间起到传导活性离子的作用。本申请对所述电解液的种类没有特别的限制，可根据实际需求进行选择。
所述电解液包括电解质盐和溶剂。所述电解质盐和所述溶剂的种类不受具体的限制，可根据实际需求进行选择。
当本申请的二次电池为锂离子电池时，作为示例，所述电解质盐可包括但不限于六氟磷酸锂(LiPF 6)、四氟硼酸锂(LiBF 4)、高氯酸锂(LiClO 4)、六氟砷酸锂(LiAsF 6)、双氟磺酰亚胺锂(LiFSI)、双三氟甲磺酰亚胺锂(LiTFSI)、三氟甲磺酸锂(LiTFS)、二氟草酸硼酸锂(LiDFOB)、二草酸硼酸锂(LiBOB)、二氟磷酸锂(LiPO 2F 2)、二氟二草酸磷酸锂(LiDFOP)和四氟草酸磷酸锂(LiTFOP)中的一种或多种。
当本申请的二次电池为钠离子电池时，作为示例，所述电解质盐可包括但不限于六氟磷酸钠(NaPF 6)、四氟硼酸钠(NaBF 4)、高氯酸钠(NaClO 4)、六氟砷酸钠(NaAsF 6)、双氟磺酰亚胺钠(NaFSI)、双三氟甲磺酰亚胺钠(NaTFSI)、三氟甲磺酸钠(NaTFS)、二氟草酸硼酸钠(NaDFOB)、二草酸硼酸钠(NaBOB)、二氟磷酸钠(NaPO 2F 2)、二氟二草酸磷酸钠(NaDFOP)和四氟草酸磷酸钠(NaTFOP)中的一种或多种。
作为示例，所述溶剂可包括但不限于碳酸乙烯酯(EC)、碳酸亚丙酯(PC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)、碳酸二甲酯(DMC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸亚丁酯(BC)、氟代碳酸乙烯酯(FEC)、甲酸甲酯(MF)、乙酸甲酯(MA)、乙酸乙酯(EA)、乙酸丙酯(PA)、丙酸甲酯(MP)、丙酸乙酯(EP)、丙酸丙酯(PP)、丁酸甲酯(MB)、丁酸乙酯(EB)、1,4-丁内酯(GBL)、环丁砜(SF)、二甲砜(MSM)、甲乙砜(EMS)和二乙砜(ESE)中的一种或多种。
在一些实施例中，所述电解液中还可选地包括添加剂。例如，所述添加剂可以包括负极成膜添加剂，也可以包括正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温性能的添加剂、改善电池低温功率性能的添加剂等。
在一些实施例中，所述正极极片、所述隔离膜和所述负极极片可通过卷绕工艺和/或 叠片工艺制成电极组件。
在一些实施例中，所述二次电池可包括外包装。该外包装可用于封装上述电极组件及电解液。
在一些实施例中，所述二次电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。所述二次电池的外包装也可以是软包，例如袋式软包。所述软包的材质可以是塑料，如聚丙烯(PP)、聚对苯二甲酸丁二醇酯(PBT)和聚丁二酸丁二醇酯(PBS)中的一种或多种。
本申请对二次电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。如图1是作为一个示例的方形结构的二次电池5。
在一些实施例中，如图2所示，外包装可包括壳体51和盖板53。壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53用于盖设所述开口，以封闭所述容纳腔。正极极片、负极极片和隔离膜可经卷绕工艺和/或叠片工艺形成电极组件52。电极组件52封装于所述容纳腔。电解液浸润于电极组件52中。二次电池5所含电极组件52的数量可以为一个或多个，可根据需求来调节。
本申请的二次电池的制备方法是公知的。在一些实施例中，可将正极极片、隔离膜、负极极片和电解液组装形成二次电池。作为示例，可将正极极片、隔离膜、负极极片经卷绕工艺和/或叠片工艺形成电极组件，将电极组件置于外包装中，烘干后注入电解液，经过真空封装、静置、化成、整形等工序，得到二次电池。
在本申请的一些实施例中，根据本申请的二次电池可以组装成电池模块，电池模块所含二次电池的数量可以为多个，具体数量可根据电池模块的应用和容量来调节。
图3是作为一个示例的电池模块4的示意图。如图3所示，在电池模块4中，多个二次电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个二次电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的外壳，多个二次电池5容纳于该容纳空间。
在一些实施例中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以根据电池包的应用和容量进行调节。
图4和图5是作为一个示例的电池包1的示意图。如图4和图5所示，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2用于盖设下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
用电装置
本申请第五方面提供一种用电装置，所述用电装置包括本申请的二次电池、电池模块或电池包中的至少一种。所述二次电池、电池模块或电池包可以用作所述用电装置的电源，也可以用作所述用电装置的能量存储单元。所述用电装置可以但不限于是移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等。
所述用电装置可以根据其使用需求来选择二次电池、电池模块或电池包。
图6是作为一个示例的用电装置的示意图。该用电装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该用电装置对高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的用电装置可以是手机、平板电脑、笔记本电脑等。该用电装置通常要求轻薄化，可以采用二次电池作为电源。
安施例
下述实施例更具体地描述了本申请公开的内容，这些实施例仅仅用于阐述性说明，因为在本申请公开内容的范围内进行各种修改和变化对本领域技术人员来说是明显的。除非另有声明，以下实施例中所报道的所有份、百分比和比值都是基于质量计，而且实施例中使用的所有试剂都可商购获得或是按照常规方法进行合成获得，并且可直接使用而无需进一步处理，以及实施例中使用的仪器均可商购获得。
实施例1-10和对比例2-7的正极极片均按照如下方法制备。
向反应釜中加入聚乙烯醇4g、明胶4g、去离子水300g，启动搅拌，搅拌速度控制为300转/分钟；将高纯氮气通入反应釜液面以下除氧0.5小时，同时升温至70℃；按照表1所示组成加入第一单体、第二单体、第三单体、第四单体、引发剂偶氮二异丁酸二甲酯0.4g和链转移剂十二烷基硫醇0.4g，之后加热至70℃并恒温反应6小时，得到聚合物分散液；将所获得的聚合物分散液经过滤、洗涤、干燥、粉碎、过筛，得到粘结剂。
将正极活性材料NCM523、导电剂碳黑、上述合成的粘结剂、溶剂NMP按照重量比为74:0.5:1.5:24充分搅拌混合均匀后得到正极浆料；之后将正极浆料均匀涂覆于正极集流体铝箔上，之后经过烘干、冷压、分切，得到正极极片。
对比例1
将正极活性材料NCM523、导电剂碳黑、粘结剂聚偏氟乙烯(PVDF)、溶剂NMP按照重量比为74:0.5:1.5:24充分搅拌混合均匀后得到正极浆料；之后将正极浆料均匀涂覆于正极集流体铝箔上，之后经过烘干、冷压、分切，得到正极极片。
性能测试
(1)粘结剂的重均分子量测试
使用沃特世(Waters)的e2695型高效液相色谱仪，通过高效液相色谱法测试上述制备的粘结剂的重均分子量。
(2)粘结剂的玻璃化转变温度Tg测试
使用梅特勒-托利多(Mettler-Toledo)的DSC-3型差示扫描量热仪测试上述制备的粘结剂的Tg。
测试按照如下步骤进行：称取10mg左右粘结剂样品于平底Al 2O 3坩埚中，抖平、盖上盖子，以10℃/min的速率从35℃升温至600℃，保护气采用氩气，吹扫气流量为50mL/min，保护气流量为20mL/min。
(3)粘结剂的溶胀性能测试
将所得到的粘结剂在1500转/分钟下高速分散溶解于溶剂N-甲基吡咯烷酮(NMP)中，配制成质量浓度为5wt％的溶液；所获得的溶液置于聚四氟乙烯培养皿中在鼓风干燥箱中于120℃烘烤4小时获得厚度为0.1mm～1mm的聚合物膜。
将所获得的聚合物膜浸泡在预定温度的碳酸酯溶剂中，达到预定时间后取出，并根 据公式计算溶胀度：溶胀度＝(浸泡后的质量－浸泡前的质量)/浸泡前的质量×100％。所述碳酸酯溶剂按照如下方法配置：将碳酸乙烯酯、碳酸二甲酯和碳酸二乙酯按照质量比为20:30:50混合均匀得到。
(4)正极极片的粘结性能测试
将正极极片裁切成宽度为20mm、长度为250mm的测试样条，取一条宽度为20mm、长度为120mm的不锈钢板，用宽度为20mm的双面胶带将测试样条粘贴在不锈钢板上，粘贴时正极极片与不锈钢板的一端对齐，另一端预留出长度为130mm的正极极片作为延伸，采用英斯特朗公司的3365型拉伸试验机测试180度剥离强度，作为正极活性材料层与正极集流体之间的粘结强度，拉伸试验机的拉伸速度为50mm/min。正极极片的剥离强度越高，表明粘结剂的粘结性越好。
表1
Figure PCTCN2022104982-appb-000006
表2
Figure PCTCN2022104982-appb-000007
Figure PCTCN2022104982-appb-000008
从表2测试结果可以得知，通过将本申请的第一单体、第二单体、第三单体和第四单体共聚后所获得的粘结剂不仅具有较低的Tg和高粘结强度，而且还具有较小的电解液溶胀度，因此本申请提供的粘结剂能够替代目前常用的聚偏氟乙烯粘结剂。
图7是实施例2合成的粘结剂的红外光谱图，测试仪器为赛默飞Nicolet iS10傅立叶变换红外光谱仪，测试标准依据GB/T 6040-2019。从图7可以看出，实施例2合成的粘结剂在2957cm -1、2927cm -1和2858cm -1附近有-CH 3和-CH 2的伸缩振动峰，在2242cm -1附近有-C≡N的伸缩振动峰，在1731cm -1附近有-C＝O-的伸缩振动峰，由此表明通过本申请提供的方法成功合成了本申请的粘结剂。
综合实施例1-10和对比例2的测试结果可以看出，当第一单体中R 14的碳原子数小于10时，由此制备粘结剂的电解液溶胀度较高，无法保证二次电池长期充放电过程中的结构稳定性。
综合实施例1-10和对比例3-6的测试结果可以看出，第一单体的摩尔含量在合适的范围内时，有利于粘结剂具有良好的柔韧性和耐电解液溶胀的特性。当第一单体的摩尔含量过高时，所得到的粘结剂在NMP中无法溶解，由此无法制备正极浆料；而当第一单体的摩尔含量过低时，则不能起到提升粘结剂耐电解液溶胀特性的作用，同时所得到的粘结剂还可能溶于电解液中。
综合实施例1-10和对比例7的测试结果可以看出，当共聚单体不包含第三单体时，所获得的粘结剂的粘结强度较低。
需要说明的是，本申请不限定于上述实施方式。上述实施方式仅为示例，在本申请的技术方案范围内具有与技术思想实质相同的构成、发挥相同作用效果的实施方式均包含在本申请的技术范围内。此外，在不脱离本申请主旨的范围内，对实施方式施加本领域技术人员能够想到的各种变形、将实施方式中的一部分构成要素加以组合而构筑的其它方式也包含在本申请的范围内。

Claims (18)

  1. 一种用于正极极片的粘结剂，包括由共聚单体形成的共聚物，其中，所述共聚单体包括第一单体、第二单体、第三单体和第四单体，所述第一单体包括式1所示的化合物中的一种或多种，所述第二单体包括式2所示的化合物中的一种或多种，所述第三单体包括式3所示的化合物中的一种或多种，所述第四单体包括式4所示的化合物中的一种或多种，
    Figure PCTCN2022104982-appb-100001
    R 11至R 13、R 21至R 23、R 31至R 33、R 41至R 43各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、羟基、以及被R a取代或未取代的如下基团组成的组中的至少一种：C1～C6烷基、C2～C6烯基、C1～C6烷氧基、C1～C6烷硫基、C3～C6环烷基、C3～C6杂环烷基，R 14表示被R a取代或未取代的C10～C30烷基、C10～C30烯基，R 24表示被R a取代或未取代的C1～C9烷基、C2～C9烯基，R 34表示氢原子、碱金属原子、羧基取代或未取代的C1～C6烷基，R a包括卤素原子、酰卤基、硝基、氰基、羧基、羟基中的一种或多种，
    基于所述共聚单体的总摩尔量为100mol％计，所述第一单体的摩尔含量为3mol％至10mol％，可选为5mol％至9mol％。
  2. 根据权利要求1所述的粘结剂，其中，基于所述共聚单体的总摩尔量为100mol％计，
    所述第二单体的摩尔含量为1mol％至30mol％，可选为8mol％至30mol％；和/或，
    所述第三单体的摩尔含量为1mol％至10mol％，可选为3mol％至10mol％；和/或，
    所述第四单体的摩尔含量为50mol％至95mol％，可选为60mol％至84mol％。
  3. 根据权利要求1或2所述的粘结剂，其中，
    R 11至R 13各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、C1～C6烷基、C1～C6卤代烷基，可选地，R 11至R 13均表示氢原子；和/或，
    R 21至R 23各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、C1～C6烷基、C1～C6卤代烷基，可选地，R 21至R 23均表示氢原子；和/或，
    R 31至R 33各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、C1～C6烷基、C1～C6卤代烷基，可选地，R 31至R 33均表示氢原子；和/或，
    R 41至R 43各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、C1～C6烷基、C1～C6卤代烷基，可选地，R 41至R 43均表示氢原子；和/或，
    R 14表示被R a取代或未取代的C14～C22烷基、C14～C22烯基，可选地表示被R a取代或未取代的十二烷基、十四烷基、十六烷基、十八烷基、二十烷基、二十二烷基。
  4. 根据权利要求1-3中任一项所述的粘结剂，其中，
    所述第一单体包括丙烯酸癸酯、丙烯酸异癸酯、丙烯酸十一烷基酯、丙烯酸十二烷基酯、丙烯酸十三烷基酯、丙烯酸十四烷基酯、丙烯酸十五烷基酯、丙烯酸十六烷基酯、丙烯酸十七烷基酯、丙烯酸十八烷基酯、丙烯酸异十八酯、丙烯酸十九烷基酯、丙烯酸-2-甲基十九烷基酯、丙烯酸二十烷基酯、丙烯酸二十一烷基酯、丙烯酸二十二烷基酯、油基甲基丙烯酸酯、甲基丙烯酸癸酯、甲基丙烯酸异癸酯、甲基丙烯酸十一烷基酯、甲基丙烯酸十二烷基酯、2-丁基辛基甲基丙烯酸酯、甲基丙烯酸十三烷基酯、甲基丙烯酸十四烷基酯、甲基丙烯酸十五烷基酯、甲基丙烯酸十六烷基酯、甲基丙烯酸十七烷基酯、甲基丙烯酸十八烷基酯、甲基丙烯酸十九烷基酯、甲基丙烯酸二十烷基酯、甲基丙烯酸二十一烷基酯、甲基丙烯酸二十二烷基酯中的一种或多种，可选地包括丙烯酸十二烷基酯、丙烯酸十四烷基酯、丙烯酸十六烷基酯、丙烯酸十八烷基酯、丙烯酸二十烷基酯、丙烯酸二十二烷基酯、油基甲基丙烯酸酯、甲基丙烯酸癸酯、甲基丙烯酸十二烷基酯、甲基丙烯酸十四烷基酯、甲基丙烯酸十六烷基酯、甲基丙烯酸十八烷基酯、甲基丙烯酸二十烷基酯、甲基丙烯酸二十二烷基酯中的一种或多种；和/或，
    所述第二单体包括丙烯酸甲酯、丙烯酸乙酯、丙烯酸丙酯、丙烯酸异丙酯、丙烯酸丁酯、丙烯酸异丁酯、丙烯酸戊酯、丙烯酸异戊酯、丙烯酸己酯、丙烯酸乙基己酯、丙烯酸庚酯、丙烯酸辛酯、丙烯酸异辛酯、丙烯酸壬酯、丙烯酸异壬酯、丙烯酸羟乙酯、丙烯酸羟丙酯、丙烯酸羟丁酯、甲基丙烯酸甲酯、甲基丙烯酸乙酯、甲基丙烯酸丙酯、甲基丙烯酸异丙酯、甲基丙烯酸丙烯酸羟乙基己内酯、丁酯、甲基丙烯酸异丁酯、甲基丙烯酸戊酯、甲基丙烯酸异戊酯、甲基丙烯酸己酯、甲基丙烯酸乙基己酯、甲基丙烯酸庚酯、甲基丙烯酸辛酯、甲基丙烯酸异辛酯、甲基丙烯酸壬酯、甲基丙烯酸异壬酯、甲基丙烯酸羟丙酯、甲基丙烯酸羟丁酯中的一种或多种，可选地包括丙烯酸甲酯、丙烯酸乙酯、丙烯酸丙酯、丙烯酸异丙酯、丙烯酸丁酯、丙烯酸异丁酯、丙烯酸戊酯、丙烯酸异戊酯、丙烯酸己酯、丙烯酸乙基己酯、丙烯酸庚酯、丙烯酸辛酯、丙烯酸异辛酯、丙烯酸壬酯、丙烯酸异壬酯、丙烯酸羟乙酯、丙烯酸羟丙酯、丙烯酸羟丁酯中的一种或多种；和/或，
    所述第三单体包括丙烯酸、衣康酸、β-(丙烯酰氧)丙酸、马来酸、富马酸、丙烯酸锂、丙烯酸钠、甲基丙烯酸、甲基丙烯酸锂、甲基丙烯酸钠中的一种或多种，可选地包 括丙烯酸、衣康酸、β-(丙烯酰氧)丙酸、马来酸、富马酸、丙烯酸锂、丙烯酸钠中的一种或多种；和/或，
    所述第四单体包括丙烯腈、甲基丙烯腈、三氟甲基丙烯腈、乙基丙烯腈、2-氯丙烯腈、2-甲基-2-丁烯腈中的一种或多种，可选地包括丙烯腈。
  5. 根据权利要求1-4中任一项所述的粘结剂，其中，所述共聚单体还包括第五单体，所述第五单体包括丙烯酰胺类单体、脂肪族单烯烃类单体、脂肪族共轭二烯烃类单体中的一种或多种，
    可选地，所述丙烯酰胺类单体包括丙烯酰胺、甲基丙烯酰胺、羟甲基丙烯酰胺、羟乙基丙烯酰胺中的一种或多种；
    可选地，所述脂肪族单烯烃类单体包括卤素取代或未取代的乙烯、丙烯、丁烯中的一种或多种；
    可选地，所述脂肪族共轭二烯烃类单体包括卤素取代或未取代的丁二烯、异戊二烯中的一种或多种。
  6. 根据权利要求1-5中任一项所述的粘结剂，其中，所述粘结剂还包括分散剂、引发剂、链转移剂中的一种或多种，
    可选地，所述分散剂为有机分散剂，更可选地包括聚乙烯醇、明胶、羧甲基纤维素、聚乙二醇、聚丙烯酸盐中的一种或多种；
    可选地，所述引发剂为油溶性引发剂，更可选地包括偶氮类引发剂和有机过氧类引发剂中的一种或多种；
    可选地，所述链转移剂包括十二烷基硫醇、十六烷基硫醇、十八烷基硫醇中的一种或多种。
  7. 根据权利要求1-6中任一项所述的粘结剂，其中，所述粘结剂的重均分子量为10万至100万，可选为10万至50万。
  8. 根据权利要求1-7中任一项所述的粘结剂，其中，所述粘结剂的玻璃化转变温度在50℃以下，可选为0℃至50℃。
  9. 根据权利要求1-8中任一项所述的粘结剂，其中，
    所述粘结剂在25℃环境中于碳酸酯溶剂中浸泡7天的溶胀度在10％至70％之间；和/或，
    所述粘结剂在60℃环境中于碳酸酯溶剂中浸泡3天的溶胀度在15％至100％之间，
    所述碳酸酯溶剂按照如下方法配置：将碳酸乙烯酯、碳酸二甲酯和碳酸二乙酯按照质量比为20:30:50混合均匀得到。
  10. 一种用于合成权利要求1-9中任一项所述的粘结剂的方法，包括以下步骤：
    S1，提供共聚单体：所述共聚单体包括第一单体、第二单体、第三单体和第四单体，所述第一单体包括式1所示的化合物中的一种或多种，所述第二单体包括式2所示的化合物中的一种或多种，所述第三单体包括式3所示的化合物中的一种或多种，所述第四单体包括式4所示的化合物中的一种或多种，
    Figure PCTCN2022104982-appb-100002
    R 11至R 13、R 21至R 23、R 31至R 33、R 41至R 43各自独立地表示氢原子、卤素原子、酰卤基、硝基、氰基、羧基、羟基、以及被R a取代或未取代的如下基团组成的组中的至少一种：C1～C6烷基、C2～C6烯基、C1～C6烷氧基、C1～C6烷硫基、C3～C6环烷基、C3～C6杂环烷基，R 14表示被R a取代或未取代的C10～C30烷基、C10～C30烯基，R 24表示被R a取代或未取代的C1～C9烷基、C2～C9烯基，R 34表示氢原子、碱金属原子、羧基取代或未取代的C1～C6烷基，R a包括卤素原子、酰卤基、硝基、氰基、羧基、羟基中的一种或多种，基于所述共聚单体的总摩尔量为100mol％计，所述第一单体的摩尔含量为3mol％至10mol％，可选为5mol％至9mol％；
    S2，共聚单体悬浮聚合：向反应釜中加入分散剂和去离子水，将惰性气体通入反应釜液面以下，在搅拌状态下升温至反应温度，然后在搅拌状态下加入所述共聚单体、引发剂和链转移剂进行聚合反应，反应结束后得到聚合物分散液，再将所获得的聚合物分散液经过滤、洗涤、干燥，得到所述粘结剂。
  11. 根据权利要求10所述的方法，其中，所述共聚单体还包括第五单体，所述第五单体包括丙烯酰胺类单体、脂肪族单烯烃类单体、脂肪族共轭二烯烃类单体中的一种或多种。
  12. 根据权利要求10或11所述的方法，其中，
    所述反应温度为65℃至85℃；和/或，
    所述反应时间为2小时至8小时；和/或，
    所述搅拌速度为200转/分钟至400转/分钟。
  13. 根据权利要求10-12中任一项所述的方法，其中，
    所述分散剂为有机分散剂，可选地包括聚乙烯醇、明胶、羧甲基纤维素、聚乙二醇、聚丙烯酸盐中的一种或多种；和/或，
    所述引发剂为油溶性引发剂，可选地包括偶氮类引发剂和有机过氧类引发剂中的一种或多种；和/或，
    所述链转移剂包括十二烷基硫醇、十六烷基硫醇、十八烷基硫醇中的一种或多种。
  14. 根据权利要求10-13中任一项所述的方法，其中，基于所述共聚单体的总质量为100wt％计，
    所述分散剂的质量百分含量为0.1wt％至2wt％；和/或，
    所述引发剂的质量百分含量为1wt％至10wt％；和/或，
    所述链转移剂的质量百分含量为1wt％至5wt％。
  15. 一种正极极片，包括正极集流体以及位于所述正极集流体至少一个表面的正极活性材料层，其中，所述正极活性材料层包括权利要求1-9中任一项所述的粘结剂或通过权利要求10-14中任一项所述的方法合成的粘结剂。
  16. 根据权利要求15所述的正极极片，其中，所述正极活性材料层与所述正极集流体之间的粘结强度为≥8N/m。
  17. 一种二次电池，包括权利要求15或16所述的正极极片。
  18. 一种用电装置，包括权利要求17所述的二次电池。
PCT/CN2022/104982 2022-07-11 2022-07-11 用于正极极片的粘结剂及其合成方法、以及包含其的正极极片、二次电池及用电装置 WO2024011371A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/CN2022/104982 WO2024011371A1 (zh) 2022-07-11 2022-07-11 用于正极极片的粘结剂及其合成方法、以及包含其的正极极片、二次电池及用电装置

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2022/104982 WO2024011371A1 (zh) 2022-07-11 2022-07-11 用于正极极片的粘结剂及其合成方法、以及包含其的正极极片、二次电池及用电装置

Publications (1)

Publication Number Publication Date
WO2024011371A1 true WO2024011371A1 (zh) 2024-01-18

Family

ID=89535176

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2022/104982 WO2024011371A1 (zh) 2022-07-11 2022-07-11 用于正极极片的粘结剂及其合成方法、以及包含其的正极极片、二次电池及用电装置

Country Status (1)

Country Link
WO (1) WO2024011371A1 (zh)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004227974A (ja) * 2003-01-24 2004-08-12 Nippon Zeon Co Ltd 電極用スラリー組成物、電極および二次電池
CN104037419A (zh) * 2013-03-07 2014-09-10 日本电石工业株式会社 锂离子二次电池的电极用粘合剂、电极用浆料、锂离子二次电池用电极以及锂离子二次电池
WO2018145646A1 (zh) * 2017-02-08 2018-08-16 北京蓝海黑石科技有限公司 一种锂离子电池正极水性粘合剂及其制备方法
CN112952092A (zh) * 2019-12-10 2021-06-11 惠州比亚迪电池有限公司 正极粘结剂及其制备方法、正极浆料、正极和锂离子电池
CN113527572A (zh) * 2020-11-13 2021-10-22 深圳市研一新材料有限责任公司 一种锂离子电池用水性增稠分散剂、水性粘结剂及其制备方法
CN114560973A (zh) * 2021-01-29 2022-05-31 深圳市研一新材料有限责任公司 一种锂离子电池正极水性粘结剂及其制备方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004227974A (ja) * 2003-01-24 2004-08-12 Nippon Zeon Co Ltd 電極用スラリー組成物、電極および二次電池
CN104037419A (zh) * 2013-03-07 2014-09-10 日本电石工业株式会社 锂离子二次电池的电极用粘合剂、电极用浆料、锂离子二次电池用电极以及锂离子二次电池
WO2018145646A1 (zh) * 2017-02-08 2018-08-16 北京蓝海黑石科技有限公司 一种锂离子电池正极水性粘合剂及其制备方法
CN112952092A (zh) * 2019-12-10 2021-06-11 惠州比亚迪电池有限公司 正极粘结剂及其制备方法、正极浆料、正极和锂离子电池
CN113527572A (zh) * 2020-11-13 2021-10-22 深圳市研一新材料有限责任公司 一种锂离子电池用水性增稠分散剂、水性粘结剂及其制备方法
CN114560973A (zh) * 2021-01-29 2022-05-31 深圳市研一新材料有限责任公司 一种锂离子电池正极水性粘结剂及其制备方法

Similar Documents

Publication Publication Date Title
CN108780893B (zh) 负极用粘合剂组合物、负极用浆料、负极和锂离子二次电池
KR101637889B1 (ko) 접착력이 우수한 이차전지용 바인더
US11978905B2 (en) Secondary battery, apparatus containing the secondary battery, method for the preparation of the secondary battery, and binder composition
KR102432637B1 (ko) 공중합체 조성물을 포함하는 바인더, 상기 바인더를 포함하는 이차전지용 음극 및 상기 음극을 포함하는 이차전지
CN108242556B (zh) 电解液及二次电池
KR20070076151A (ko) 바인더로서 폴리비닐알콜을 포함하는 전극 합제 및 이를기반으로 한 리튬 이차전지
WO2023061135A1 (zh) 一种粘结剂化合物及其制备方法
US20220285687A1 (en) Secondary battery, method for preparing the same, copolymer and apparatus
WO2024045554A1 (zh) 粘结剂、制备方法、正极极片、二次电池及用电装置
TWI795390B (zh) 非水電解質電池用黏合劑組成物、以及使用其之非水電解質電池用黏合劑水溶液、非水電解質電池用漿體組成物、非水電解質電池用電極、及非水電解質電池
US11139477B2 (en) Binder composition for lithium secondary battery and lithium secondary battery including the same
WO2024011371A1 (zh) 用于正极极片的粘结剂及其合成方法、以及包含其的正极极片、二次电池及用电装置
WO2023225799A1 (zh) 二次电池以及包含其的电池模块、电池包及用电装置
CN116284536A (zh) 共聚物和用于锂电池的粘结剂
KR20210032386A (ko) 비수계 전지 전극용 바인더용 공중합체, 및 비수계 전지 전극 제조용 슬러리
WO2023283960A1 (zh) 正极极片、二次电池及其制备方法与包含该二次电池的电池模块、电池包和用电装置
CN107293783B (zh) 电解液及锂离子电池
CN117143545B (zh) 粘结剂及其制备方法、负极极片、电池和用电装置
WO2024040572A1 (zh) 用于正极极片的水性粘接剂以及由其制备的正极极片
WO2023230786A1 (zh) 粘结剂、制备方法、二次电池、电池模块、电池包及用电装置
CN117143547B (zh) 粘结剂及其制备方法、负极极片、电池和用电装置
WO2024045158A1 (zh) 酰胺类化合物及其制备方法、极片、二次电池和用电装置
WO2023225804A1 (zh) 二次电池以及包含其的电池模块、电池包及用电装置
WO2024077507A1 (zh) 粘结组合物、电极浆料、电极极片、二次电池及用电装置
WO2024000167A1 (zh) 聚合物及其制备方法、极片、二次电池、电池模块、电池包和用电装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22950502

Country of ref document: EP

Kind code of ref document: A1