Binder composition, pole piece, battery, preparation method and electronic equipment

Abstract

The invention provides a binder composition, a pole piece, a battery, a preparation method and electronic equipment. The binder composition comprises a binder, the binder comprises a first chain link, a second chain link and a third chain link, the first chain link is a chain link as shown in a formula 1, the second chain link is a chain link as shown in a formula 2, and the third chain link comprises a chain link as shown in a formula 3 or a formula 4; in the binder, the molar percentage content a% of the first chain link, the molar percentage content b% of the second chain link and the molar percentage content c% of the third chain link meet the following conditions: a + b + c = 100, 80 < = alt; 100, 0 lt; b < = 18, 0lt; c < = 2, 1lt; b + c < = 20; in the formulas 1-4, R1, R2, R3, R4 and R5 are respectively and independently selected from substituted or unsubstituted C1-C30 alkyl groups; x is halogen. The binder composition can improve the rate capability and cycle performance of the battery.

Description

Technical Field

[0001] This application relates to the field of electrochemical technology, specifically to a binder composition, an electrode, a battery and its preparation method, and an electronic device. Background Technology

[0002] All-solid-state batteries are more suitable for medium to large-scale energy storage devices due to their high safety and high energy density. Sulfide all-solid-state batteries are a commonly used type of all-solid-state battery. However, because the solid electrolyte and the positive and / or negative active materials are in solid-solid interface contact in sulfide all-solid-state batteries, their interface resistance is relatively high, which limits the industrialization of sulfide all-solid-state batteries.

[0003] In the electrodes of sulfide all-solid-state batteries, the active layer typically includes active materials, a sulfide electrolyte, a conductive agent, and a binder. The binder is in direct contact with the active materials, sulfide electrolyte, and conductive agent within the electrode. The distribution of the binder not only affects the overall uniformity of the electrode but also directly relates to the ion and electron transport characteristics within the positive and / or negative electrodes. Therefore, improving the binder can address the interfacial contact between the positive and / or negative active materials and the solid electrolyte, thereby enhancing the electrochemical performance of sulfide all-solid-state batteries.

[0004] Currently, the binders commonly used in sulfide all-solid-state batteries include polar binders and non-polar binders. Polar binders have poor solubility in non-polar solvents and are prone to decomposing the sulfide electrolyte. Non-polar binders (e.g., at least one of nitrile rubber, styrene-butadiene rubber, silicone rubber, and ethyl cellulose) have good solubility in non-polar solvents, but their interaction with the active material and current collector is weak. This not only hinders electron transport and reduces the rate performance of the battery, but also easily leads to poor adhesion between the active layer and the current collector, resulting in poor cycle stability of the battery. Summary of the Invention

[0005] In view of this, this application provides a binder composition in which the binder has good solubility in low polarity or non-polar solvents and does not undergo side reactions with the sulfide electrolyte, thus not causing degradation of the sulfide electrolyte; moreover, the binder has a strong interaction with the active material and the current collector, which can improve the rate performance and cycle performance of the battery.

[0006] This application provides an electrode comprising the above-described binder composition, thereby improving the rate performance and cycle performance of the battery when used in a battery.

[0007] This application provides a battery including the aforementioned electrode, which has excellent rate performance and cycle performance.

[0008] This application provides a method for preparing a battery, which can produce the aforementioned battery. This method is simple to operate and suitable for widespread application.

[0009] This application provides an electronic device including the aforementioned battery, which has excellent fast charging and battery life capabilities and has broad market application prospects.

[0010] This application provides an adhesive composition comprising an adhesive, the adhesive comprising a first link, a second link, and a third link, wherein the first link is a link shown in Formula 1, the second link is a link shown in Formula 2, and the third link comprises a link shown in Formula 3 or Formula 4.

[0011] In the adhesive, the molar percentage of the first link a%, the molar percentage of the second link b%, and the molar percentage of the third link c% satisfy the following:

[0012] a + b + c = 100, 80 ≤ a < 100, 0 <b≤18,0<c≤2,1<b+c≤20;

[0013]

[0014] R1, R2, R3, R4, and R5 are each independently selected from substituted or unsubstituted C1-C30 alkyl groups;

[0015] X is a halogen.

[0016] The adhesive composition as described above, wherein 97 ≤ a < 99.

[0017] The adhesive composition as described above, wherein the number average molecular weight of the adhesive is M. n 10000≤M n ≤1,000,000; and / or, the weight-average molecular weight of the adhesive is M. w 50000≤M w ≤5000000.

[0018] The adhesive composition as described above, wherein the Mooney viscosity of the adhesive is ML, 10 ≤ ML ≤ 200; and / or,

[0019] The glass transition temperature of the adhesive is T. g T g ≤10℃.

[0020] The adhesive composition as described above, wherein the tensile strength of the adhesive is ≥0.1 MPa; and / or,

[0021] The antioxidant potential of the adhesive is ≥4.3V.

[0022] The adhesive composition as described above further includes a solvent;

[0023] The dipole moment of the solvent is ≤2.5D.

[0024] The adhesive composition as described above, wherein the solvent is selected from at least one of xylene, butyl butyrate, decane, isobutyl isobutyrate, anisole, toluene, and isoalkanes.

[0025] The adhesive composition as described above, wherein the adhesive composition contains ≤20% by mass of adhesive.

[0026] The adhesive composition as described above, wherein the adhesive has a mass percentage content of 5-10%.

[0027] This application provides an electrode, wherein the electrode includes a current collector and an active layer located on at least one surface of the current collector;

[0028] The active layer comprises the adhesive composition described above.

[0029] The electrode as described above, wherein the active layer further includes a sulfide electrolyte.

[0030] In the electrode as described above, the peel force between the active layer and the current collector is ≥0.01 N / cm.

[0031] This application provides a battery, which includes the electrodes described above.

[0032] This application provides a method for preparing a battery, comprising:

[0033] An electrode assembly is obtained by stacking a positive electrode, a solid electrolyte, and a negative electrode; or, an electrode assembly is obtained by first stacking a positive electrode, a solid electrolyte, and a negative electrode, and then winding them.

[0034] The battery is obtained by placing the electrode assembly in an outer package, sealing it, and then forming it.

[0035] Wherein, the positive electrode and / or the negative electrode are electrodes as described above.

[0036] This application provides an electronic device, which includes the battery described above.

[0037] The binder composition provided in this application has good solubility in low polar or non-polar solvents and does not undergo side reactions with sulfide electrolytes, thus preventing degradation of the sulfide electrolytes. Moreover, the binder has strong interaction with the active material and current collector, which can improve the rate performance and cycle performance of the battery.

[0038] The electrode provided in this application includes the above-mentioned binder composition, which, when applied to a battery, can improve the rate performance and cycle performance of the battery.

[0039] The battery provided in this application includes the aforementioned electrode, and therefore the battery has excellent rate performance and cycle performance.

[0040] The battery preparation method provided in this application can produce the aforementioned battery. This preparation method is simple to operate and suitable for widespread application.

[0041] The electronic device provided in this application includes the aforementioned battery, and the electronic device has excellent battery life and fast charging capability. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] Currently, research mainly focuses on preparing novel binders using monomer polymerization with side chains containing different functional groups (e.g., ester groups). The resulting binders typically have a high proportion of polar functional groups, leading to poor solubility in low-polarity solvents. Furthermore, the binders tend to exacerbate the instability of sulfide electrolytes, causing their decomposition and negatively impacting battery cycle performance. In light of this, the inventors discovered that the content of polar and non-polar functional groups in the binder's molecular chain affects its ion transport capacity, solubility, and stability, thereby influencing battery performance.

[0044] A first aspect of this application provides an adhesive composition comprising an adhesive, the adhesive comprising a first link, a second link, and a third link, the first link being a link shown in Formula 1, the second link being a link shown in Formula 2, and the third link comprising a link shown in Formula 3 or Formula 4.

[0045] In the adhesive, the molar percentages of the first link (a%), the second link (b%), and the third link (c%) satisfy the following:

[0046] a + b + c = 100, 80 ≤ a < 100, 0 <b≤18,0<c≤2,1<b+c≤20;

[0047]

[0048] R1, R2, R3, R4, and R5 are each independently selected from substituted or unsubstituted C1-C30 alkyl groups;

[0049] X is a halogen.

[0050] This application does not limit the connection order of the first, second, and third segments in the adhesive. The first, second, and third segments can be connected regularly or irregularly. For example, the molecular chain of the adhesive can be first segment-second segment-third segment, first segment-third segment-second segment, or second segment-first segment-third segment.

[0051] The substituted or unsubstituted C1-C30 alkyl group can be a substituted straight-chain alkyl group, an unsubstituted straight-chain alkyl group, a substituted branched alkyl group, or an unsubstituted branched alkyl group; the halogen can be F, Cl, Br, or I.

[0052] In the adhesive composition of this application, the adhesive molecular chain includes a high proportion of saturated alkane molecular chain segments (first segments) and a low proportion of polar molecular chain segments (third segments).

[0053] The first segment is a non-polar segment, which ensures good solubility of the binder in low-polarity or non-polar solvents. In low-polarity or non-polar solvents, the molecular chain segments of the binder are more extended, resulting in more uniform dispersion of the slurry containing the binder. This leads to uniform dispersion of the components in the active layer and improves the consistency of the electrode. Furthermore, when the content of non-polar segments is high, the binder is less likely to undergo side reactions with the sulfide electrolyte, preventing degradation of the sulfide electrolyte and improving the stability of the electrode.

[0054] The epoxy or halogen groups in the third segment have excellent lithium-ion transport performance, which can make the electrode have more ion transport channels, minimize the impact of non-polar segments on the overall ion and electron transport performance of the electrode, and make the electrode have excellent ion transport performance. Furthermore, the addition of epoxy or halogen groups can enhance the interaction force between the components in the active layer (e.g., enhance the interaction force between the binder and the sulfide electrolyte, the positive electrode active material and / or the negative electrode active material), while improving the adhesion between the electrode active layer and the current collector, preventing the active layer from separating from the current collector during battery cycling and extending the battery cycle life.

[0055] The second linker can better connect the first and third linkser, and the unsaturated bonds in the second linker can provide cross-linking sites for the binder. Depending on the application scenario, the binder can be cross-linked between binder molecular chains by opening double bonds to form a three-dimensional network structure, which further enhances the mechanical strength of the electrode.

[0056] Furthermore, by precisely controlling the proportions between the various segments of the binder, this application enables the segments to work synergistically, resulting in superior cycle performance and rate performance of the battery. Moreover, in this application, the molar content of each segment in the binder can be selected based on the positive and negative electrode active materials to better match the binder with the positive and / or negative electrode active materials, thereby improving the binder's versatility.

[0057] Furthermore, when 97≤a<99, the links can be more fully matched, improving the battery's cycle performance and rate performance.

[0058] This application can further define the specific properties of the binder to enable batteries including the binder to exhibit superior cycle performance and rate performance. For example, in some embodiments of the invention, the number-average molecular weight of the binder is M. n 10000≤M n ≤1,000,000; and / or, the weight-average molecular weight of the adhesive is M. w 50000≤M w ≤5,000,000. In some embodiments, the binder composition can be tested using gel permeation chromatography (GPC) to obtain the number-average molecular weight and weight-average molecular weight of the binder.

[0059] In this application, binders with different dispersion indices can be prepared to adapt to different active materials. In some embodiments of this application, the polymer dispersion index (PDI) of the binder is 1 ≤ PDI ≤ 10, which helps to improve the cycle stability of the battery. In some embodiments, the binder composition can be tested using gel permeation chromatography to obtain the number-average molecular weight and weight-average molecular weight of the binder. Based on the number-average molecular weight and weight-average molecular weight of the binder, the polymer dispersion index (PDI) of the binder is calculated, where PDI = M... w / M n .

[0060] In some embodiments of this application, the Mooney viscosity of the adhesive is ML, 10 ≤ ML ≤ 200.

[0061] The Mooney viscosity includes a first Mooney viscosity and a second Mooney viscosity. The first Mooney viscosity is measured at 100°C using a large rotor, with a preheating time of 1 minute and a test time of 4 minutes, denoted as ML(1+4)100°C. The second Mooney viscosity is measured at 125°C using a large rotor, with a preheating time of 1 minute and a test time of 8 minutes, denoted as ML(1+8)125°C. Both the first and second Mooney viscosities of this application satisfy the above-mentioned ranges. When the Mooney viscosity of the binder satisfies the above-mentioned range, the binder has suitable viscosity and rheological properties, which can improve the mechanical properties of the electrode when applied to it. In some embodiments, a Mooney viscometer can be used to test the Mooney viscosity of the binder.

[0062] The inventors also discovered that when the glass transition temperature of the adhesive is T g T g At temperatures ≤10°C, the binder composition can improve the mechanical properties of the electrode when applied. In some embodiments, the glass transition temperature of the binder can be tested using a differential scanning calorimeter.

[0063] Furthermore, when the tensile strength of the adhesive is ≥0.1 MPa, the electrode comprising the adhesive composition exhibits superior mechanical properties. In some embodiments, the tensile strength of the adhesive can be obtained using a universal tensile testing machine.

[0064] In some embodiments of this application, the antioxidant potential of the binder is ≥4.3V. Batteries incorporating the binder of this application exhibit excellent high-voltage performance. In some embodiments, the binder can be assembled with stainless steel sheets and lithium sheets to form a battery, and the antioxidant potential of the binder can be obtained by performing a linear cyclic voltammetry scan on the battery using an electrochemical workstation.

[0065] In some embodiments of this application, the adhesive composition further includes a solvent;

[0066] The dipole moment of the solvent is ≤2.5D.

[0067] In this application, the solvent with a dipole moment ≤ 2.5D is a low-polarity or non-polar solvent. The binder with the aforementioned special molecular chain segments can dissolve more fully in solvents with low dipole moments, resulting in a binder composition with uniform components. Furthermore, this binder composition is less prone to side reactions with sulfide electrolytes and can be widely used in sulfide all-solid-state batteries to improve their rate performance and cycle performance. The binder composition of this application can ensure the uniformity of the wet slurry and improve the preparation efficiency of the electrode.

[0068] In some embodiments, the binder composition can be tested using infrared spectroscopy or nuclear magnetic resonance spectroscopy to obtain the molar percentage content of each linker in the binder.

[0069] In some embodiments of this application, the solvent may be selected from at least one of low-polarity solvents such as xylene, butyl butyrate, decane, isobutyl isobutyrate, anisole, toluene, and isoalkanes.

[0070] In some embodiments of this application, when the mass percentage of the binder in the binder composition is ≤20%, the binder can be more uniformly dispersed in the solvent, improving the uniformity of the binder composition and thus ensuring the stability of the battery. Preferably, the mass percentage of the binder in the binder composition is 5-10%.

[0071] In some embodiments of this application, the adhesive composition can be prepared by a method including the following steps:

[0072] S1. At a certain temperature, isobutylene and diene monomers are added to the first solvent in a certain proportion and mixed evenly to obtain the first solution.

[0073] S2. Add catalyst and diluent to the first solution and control the reaction temperature to carry out the first copolymerization reaction;

[0074] S3. After reacting for a certain period of time, the reaction is stopped, and the first post-treatment is performed to obtain copolymer A.

[0075] S4. Take a certain amount of copolymer A and dissolve it in the second solvent, stir it evenly to obtain the second solution;

[0076] S5. Add an epoxy agent or a halogenating agent to the second solution and control the reaction temperature to carry out the second reaction;

[0077] S6. After a certain reaction time, the reaction is stopped. The ratio of epoxy groups or halogenated groups is controlled, and a second post-treatment is performed to obtain the binder.

[0078] S7. Mix the adhesive and the third solvent evenly to prepare an adhesive composition.

[0079] The first solvent, the second solvent, and the third solvent may be the same or different, and the dipole moments of the first solvent, the second solvent, and the third solvent are all ≤2.5D;

[0080] Diene monomers may be selected from at least one of butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, and 4,5-dimethyl-1,3-octadiene.

[0081] The epoxy agent may be selected from at least one of the following: peroxy acid-hydrogen peroxide system (e.g., formic acid-H2O2, acetic acid-H2O2 or m-chloroperoxybenzoic acid), tert-butyl hydroperoxide, and dimethyldioxane.

[0082] A second aspect of this application provides an electrode comprising a current collector and an active layer located on at least one surface of the current collector, the active layer comprising the adhesive composition of the first aspect.

[0083] It is understood that in the electrode of this application, the active layer can be located on one surface of the current collector or on both surfaces of the current collector. Because the electrode of this application includes the aforementioned binder composition, it exhibits excellent ion transport performance, and the active layer of the electrode is not easily separated from the current collector. When applied to a battery, this electrode can improve the battery's cycle performance and rate performance.

[0084] The electrode in this application can be either a positive electrode or a negative electrode. When the electrode is a positive electrode, the current collector is a positive current collector and the active layer is a positive active layer; when the electrode is a negative electrode, the current collector is a negative current collector and the active layer is a negative active layer.

[0085] Due to the battery manufacturing process, the electrodes undergo drying and the battery undergoes formation, etc. Therefore, while binders can be detected from the electrodes disassembled from the battery or from the electrodes themselves, it is difficult to detect solvents.

[0086] In some embodiments of this application, when the active layer further includes a sulfide electrolyte, the epoxy groups or halogenated groups in the binder can form interaction forces with the sulfide electrolyte particles, the active material and the current collector, thereby enhancing the adhesion between the active layer and the current collector, preventing the active layer from falling off from the current collector during long-term battery cycling, and improving the electrochemical performance of the battery.

[0087] In some embodiments, the sulfide electrolyte may include Li 10 GeP2S 12 At least one of the following: Thio-LISICON, Li2S-P2S5, silver-germanium sulfide, Li2SP2S5-LiX, and Li2S-P2S5-X2.

[0088] Furthermore, when the peel force between the active layer and the current collector is ≥0.01 N / cm, when this electrode is applied to a battery, the active layer and the current collector are less likely to separate during battery cycling, which can improve the battery's cycle performance. In some embodiments, a peel strength tester can be used to obtain the peel force between the active layer and the current collector in the electrode.

[0089] A third aspect of this application provides a battery including the electrode of the second aspect.

[0090] It is understood that in the battery of this application, the positive electrode and / or negative electrode can be the electrodes of the second aspect.

[0091] The battery of this application, due to the inclusion of the second-side electrode, exhibits excellent cycle performance and rate performance.

[0092] The fourth aspect of this application provides a method for preparing a battery, comprising: stacking a positive electrode, a solid electrolyte, and a negative electrode to obtain an electrode assembly, or stacking a positive electrode, a solid electrolyte, and a negative electrode first, and then winding them to obtain an electrode assembly.

[0093] The electrode assembly is placed in an outer packaging, sealed, and formed to obtain a battery.

[0094] Among them, the positive electrode and / or negative electrode are the electrodes of the second aspect.

[0095] Specifically, in this application, a positive electrode, a solid electrolyte, and a negative electrode can be stacked to form a stacked electrode assembly, which is then placed in an outer package, sealed, and formed to form a battery. Alternatively, the positive electrode, a solid electrolyte, and a negative electrode can be stacked, wound, and then placed in an outer package to form a wound electrode assembly, which is then sealed and formed to form a battery. In some embodiments, the positive electrode can be a third-party electrode, and the negative electrode can be a commonly used negative electrode in the art. In other embodiments, the negative electrode can be a second-party electrode, and the positive electrode can be a commonly used positive electrode in the art. In still other embodiments, both the negative and positive electrodes can be second-party electrodes.

[0096] The battery preparation method of this application can produce a third-party battery. This preparation method is simple to operate and suitable for widespread application.

[0097] The fifth aspect of this application also provides an electronic device, including the battery of the third aspect.

[0098] It should be noted that the aforementioned electronic device can be any conventional device that requires electricity, such as, but not limited to, computers, electric vehicles, air conditioners, refrigerators, washing machines, microwave ovens, printers, fax machines, etc. Because the electronic device includes a third-party battery, it boasts superior battery life and fast charging performance.

[0099] The present application will be further described below with reference to specific embodiments:

[0100] Example 1

[0101] The all-solid-state battery of this embodiment is prepared by a method including the following steps:

[0102] 1) Preparation of adhesive composition

[0103] i. Isobutylene and isoprene are added to the polymerization reactor at a mass ratio of 98:2. Under an inert atmosphere, a certain amount of diluent chloromethane is added to control the total concentration of isobutylene and isoprene at 25wt%. 0.2wt% of the total solution volume of aluminum trichloride catalyst is added. After mixing evenly, the temperature of the polymerization reactor is controlled at -90℃, and the first copolymerization reaction is carried out for 1 hour to obtain a glue solution. The glue solution is dried to prepare a glue block.

[0104] ii. Dissolve 100g of the glue block in cyclohexane to prepare a 15wt% glue solution. Add a mixed solution of 5g formic acid and 85g hydrogen peroxide, stir evenly, and carry out a second copolymerization reaction at 60℃ for 1h (control c to be 0.2, i.e., the degree of epoxidation of the isoprene unit is 10%) to obtain the glue solution. Pour the glue solution into boiling water to flocculate and obtain the glue block. Place the glue block in a vacuum oven and dry at 50℃ to obtain the adhesive.

[0105] iii. Dissolve the adhesive in xylene to prepare a 5 wt% adhesive composition;

[0106] The binder in this embodiment is an isobutylene-isoprene-epoxyisoprene copolymer. In the binder, the molar percentage a% of the first link is 98%, the molar percentage b% of the second link is 1.8%, and the molar percentage c% of the third link is 0.2%. The Mooney viscosity of the binder is 50 MU; the polymer dispersion index PDI of the binder is 5; and the number average molecular weight M of the binder is... n The weight-average molecular weight M of the adhesive is 100,000. w The value is 500,000; the tensile strength of the adhesive is 0.5 MPa; the glass transition temperature T of the adhesive is... g The temperature is -60℃.

[0107] 2) Preparation of positive electrode sheet

[0108] The positive electrode active material NCM811 and the sulfide electrolyte Li 5.5 PS 4.5 Cl 1.5 The conductive agent VGCF and binder composition are added to the bottle in a mass ratio of 85:15:1:1, and stirred evenly in a stirrer to obtain a positive electrode slurry. The positive electrode slurry is then coated onto an aluminum foil with a thickness of 350μm. After drying, a positive electrode sheet including a positive electrode active layer is obtained.

[0109] The antioxidant potential of the positive electrode active layer is 4.4V.

[0110] 3) Preparation of negative electrode sheet

[0111] The negative electrode active material is micron-sized silicon, and the sulfide electrolyte is Li. 5.5 PS 4.5 Cl1.5 The conductive agent VGCF and binder composition are added to the bottle in a mass ratio of 70:30:2:3. The mixture is stirred evenly in a stirrer to obtain a negative electrode slurry. The negative electrode slurry is then coated onto a copper foil with a thickness of 150 μm. After drying, a negative electrode sheet including a negative electrode active layer is obtained.

[0112] 4) Preparation of electrolyte sheets

[0113] 0.15g of sulfide electrolyte LPSCl powder was placed in a solid-state battery mold and pressurized at 3t to prepare an electrolyte sheet with a thickness of 0.1cm.

[0114] 5) Assembly of all-solid-state batteries

[0115] In a glove box, the positive electrode, electrolyte, and negative electrode are stacked in a solid-state battery mold and pressurized to 3t to obtain an all-solid-state battery.

[0116] See Table 1 for specific parameters.

[0117] Example 2

[0118] The preparation method of the all-solid-state battery in this embodiment is basically the same as that in Example 1. The difference is in the preparation of the binder composition in step 1). In the binder, the molar percentage a% of the first link is 98%, the molar percentage b% of the second link is 1.5%, and the molar percentage c% of the third link is 0.5%.

[0119] Example 3

[0120] The preparation method of the all-solid-state battery in this embodiment is basically the same as that in Example 1. The difference is in the preparation of the binder composition in step 1). In the binder, the molar percentage a% of the first link is 98%, the molar percentage b% of the second link is 1%, and the molar percentage c% of the third link is 1%.

[0121] Example 4

[0122] The preparation method of the all-solid-state battery in this embodiment is basically the same as that in Example 1. The difference is in the preparation of the binder composition in step 1). In the binder, the molar percentage a% of the first link is 98%, the molar percentage b% of the second link is 0.5%, and the molar percentage c% of the third link is 1.5%.

[0123] Example 5

[0124] The preparation method of the all-solid-state battery in this embodiment is basically the same as that in Example 1. The difference is in the preparation of the binder composition in step 1). In the binder, the molar percentage a% of the first link is 98%, the molar percentage b% of the second link is 0.2%, and the molar percentage c% of the third link is 1.8%.

[0125] Example 6

[0126] The preparation method of the all-solid-state battery in this embodiment is basically the same as that in Example 2, except that in step 1), butadiene is used instead of isoprene in the preparation of the binder composition.

[0127] Example 7

[0128] The preparation method of the all-solid-state battery in this embodiment is basically the same as that in Example 2. The difference is that in step 1), the binder composition is prepared by replacing the mixed solution of 5g formic acid and 85g hydrogen peroxide with 5g of halogenated reagent liquid bromine to obtain the binder isobutylene-isoprene-Cl-substituted isoprene copolymer.

[0129] Example 8

[0130] The preparation method of the all-solid-state battery in this embodiment is basically the same as that in Example 2. The difference is that in step 1), the binder composition is prepared by replacing the mixed solution of 5g formic acid and 85g hydrogen peroxide with 5g of halogenated chlorine solution to obtain the binder isobutylene-isoprene-Br-substituted isoprene copolymer.

[0131] Example 9

[0132] The preparation method of the all-solid-state battery in this embodiment is basically the same as that in Example 2. The difference is that in step 1), the binder composition is prepared by replacing the mixed solution of 5g formic acid and 85g hydrogen peroxide with 5g of halogenated fluorine gas to obtain the binder isobutylene-isoprene-F-type isoprene copolymer.

[0133] Example 10

[0134] The preparation method of the all-solid-state battery in this embodiment is basically the same as that in Example 3. The difference is that in step 1), the binder composition is prepared by dissolving the binder in decane solvent in step iii to prepare a 5wt% binder composition.

[0135] Example 11

[0136] The preparation method of the all-solid-state battery in this embodiment is basically the same as that in Example 3. The difference is that in step 1), the binder composition is prepared by dissolving the binder in xylene solvent in step iii to prepare a 10wt% binder composition.

[0137] Example 12

[0138] The preparation method of the all-solid-state battery in this embodiment is basically the same as that in Example 3. The difference is that in step 1), the binder composition is prepared by dissolving the binder in xylene solvent in step iii to prepare a 15wt% binder composition.

[0139] Example 13

[0140] The preparation method of the all-solid-state battery in this embodiment is basically the same as that in Example 3. The difference is that in step 1), the binder composition is prepared such that the molar percentage a% of the first link is 90%, the molar percentage b% of the second link is 9%, and the molar percentage c% of the third link is 1%.

[0141] Example 14

[0142] The preparation method of the all-solid-state battery in this embodiment is basically the same as that in Example 3. The difference is in the preparation of the binder composition in step 1). In the binder, the molar percentage a% of the first link is 81%, the molar percentage b% of the second link is 18%, and the molar percentage c% of the third link is 1%.

[0143] Example 15

[0144] The preparation method of the all-solid-state battery in this embodiment is basically the same as that in Example 2, except that in the preparation of the binder composition in step 1),

[0145] In i, the temperature of the polymerization reactor is -60℃;

[0146] The final binder has a Mooney viscosity of 15 MU; a polymer dispersion index (PDI) of 5; and a number-average molecular weight (M). n The weight-average molecular weight M of the adhesive is 30,000. w The value is 150,000; the tensile strength of the adhesive is 0.3 MPa; the glass transition temperature T of the adhesive is... g The temperature is -60℃.

[0147] Example 16

[0148] The preparation method of the all-solid-state battery in this embodiment is basically the same as that in Example 2, except that in the preparation of the binder composition in step 1),

[0149] In step i, the temperature of the polymerization reactor is -110℃, and 0.1wt% of aluminum trichloride catalyst is added to the total solution.

[0150] The final binder has a Mooney viscosity of 110 MU; a polymer dispersion index (PDI) of 5; and a number-average molecular weight (M). n The weight-average molecular weight M of the adhesive is 600,000. w The value is 3,000,000; the tensile strength of the adhesive is 0.8 MPa; the glass transition temperature T of the adhesive is... g The temperature is -60℃.

[0151] Comparative Example 1

[0152] The preparation method of the all-solid-state battery in this comparative example is basically the same as that in Example 1, except that the preparation of the binder composition in step 1) does not include step ii, in which the glue block in step i is dissolved in xylene to obtain the binder composition.

[0153] The adhesive does not include the third linker. In the adhesive, the molar percentage a% of the first linker is 98%, and the molar percentage b% of the second linker is 2%.

[0154] Comparative Example 2

[0155] The preparation method of the all-solid-state battery in this comparative example is basically the same as that in Example 1, except that the preparation of the binder composition in step 1) is different.

[0156] i. Add isoprene to the polymerization reactor. Under an inert atmosphere, add a certain amount of diluent chloromethane to control the isoprene concentration at 25 wt%. Add 0.2 wt% of the total solution of catalyst aluminum trichloride. After mixing evenly, control the temperature of the polymerization reactor at -90℃ and carry out the first copolymerization reaction for 1 hour to obtain a glue solution. Dry the glue solution to prepare a glue block.

[0157] ii. Dissolve the adhesive block in xylene to obtain an adhesive composition;

[0158] The binder is polybutadiene, and the binder does not include the first and third segments. In the binder, the molar percentage b% of the second segment is 100%.

[0159] Comparative Example 3

[0160] The preparation method of the all-solid-state battery in this comparative example is basically the same as that in Example 1, except that the preparation of the binder composition in step 1) is different.

[0161] i. Isobutylene is added to the polymerization reactor. Under an inert atmosphere, a certain amount of diluent chloromethane is added to control the isobutylene concentration at about 25 wt%. 0.2 wt% of the total solution volume of aluminum trichloride is added. After mixing evenly, the temperature of the polymerization reactor is controlled at -90℃, and the first copolymerization reaction is carried out for 1 hour to obtain a glue solution. The glue solution is dried to prepare a glue block.

[0162] ii. Dissolve the adhesive block in xylene to obtain an adhesive composition;

[0163] The binder is polyisobutylene. The binder does not include the second and third segments. In the binder, the molar percentage a% of the first segment is 100%.

[0164] Comparative Example 4

[0165] The preparation method of the all-solid-state battery in this comparative example is basically the same as that in Example 1, except that in step 1), the binder composition is prepared such that the molar percentage a% of the first link is 90%, the molar percentage b% of the second link is 5%, and the molar percentage c% of the third link is 5%.

[0166] Performance testing

[0167] The binder, binder composition, electrode and battery in the examples and comparative examples were subjected to the following performance tests, and the results are shown in Table 1;

[0168] 1) Molar content of each unit in the binder composition

[0169] The binder composition was tested using nuclear magnetic resonance spectroscopy to obtain the molar percentage of each unit in the binder. This included: removing the solvent from the binder composition, dissolving it in deuterated chloroform, and performing NMR testing. By calculating the proportion of proton signals of diene units and isobutylene proton signals, a and b can be obtained; by calculating the proportion of characteristic peaks of epoxy groups, c can be obtained.

[0170] 2) Electrode peeling force

[0171] The prepared electrode sheets were cut into 2cm*20cm strips and a peel tester was used to perform the peel test.

[0172] 3) Antioxidant potential

[0173] The antioxidant potential of the binder was tested using the following method: the binder, stainless steel sheet and lithium sheet were assembled into an all-solid-state battery (the stainless steel sheet, binder film and Li sheet were stacked in sequence to obtain the all-solid-state battery), and the all-solid-state battery was tested using an electrochemical workstation with linear cyclic voltammetry (LSV) scan, the test voltage range was 2 to 5 V and the scan rate was 1 mV / s.

[0174] 4) Ratio performance

[0175] The charge-discharge curves of the all-solid-state battery were monitored using the Blue Electric testing system within a voltage window of 2.5-4.25V, and the discharge capacity at different current densities (0.1C, 0.2C, 0.5C, 1C). The test temperature was 25℃. Rate performance = discharge capacity at 0.5C / discharge capacity at 0.1C.

[0176] 5) Cyclic performance

[0177] The discharge capacity of the all-solid-state battery was monitored using the Blue Electric testing system at different cycle numbers within a voltage window of 2.5-4.25V, with a test temperature of 25℃. Cycling performance is the ratio of the discharge capacity after 200 cycles to the discharge capacity after the first cycle.

[0178] 6) Relative molecular weight and polymer dispersion index

[0179] The sample was completely dissolved in the mobile phase to a concentration of 5 mg / mL, and then filtered through a 0.45 μm filter membrane. The sample solution was analyzed using gel permeation chromatography to determine the relative molecular mass M. n and M w Polymer dispersion index = M w / M n .

[0180] 7) Mooney viscosity

[0181] The Mooney viscosity of the adhesive was tested according to standard ISO 289. The sample was mixed and cut into standard-sized sheets (50 mm ± 1 mm in diameter, 6 mm ± 0.5 mm in thickness), and tested using a Mooney viscometer. The same sample was tested three times, and the arithmetic mean was taken (difference ≤ 2 Mooney values).

[0182] 8) Glass transition temperature

[0183] Take 3-6 mg of adhesive sample and record the heat flow curve of the adhesive using a differential scanning calorimeter. The test is conducted under a nitrogen atmosphere, with a temperature range of -100 to 150 °C and a heating rate of 10 °C / min.

[0184] 9) Tensile strength

[0185] The tensile properties of the adhesive were tested using a tensile testing machine from Zwick / Roell, Germany, following standard methods ISO 37 and ISO 34-1. The adhesive samples were prepared into a film (uncured) through compounding, then cut into Type II dumbbell-shaped strips for testing. The median value of three strips was taken from each test group.

[0186] Table 1

[0187]

[0188]

[0189] In Table 1, W refers to the mass percentage of the adhesive in the adhesive composition.

[0190] As can be seen from Table 1, when the binder composition in the examples is applied to the electrode, the adhesion between the active layer and the current collector is excellent, and the battery has better rate performance.

[0191] Specifically, as shown in Comparative Example 1, when the binder in the binder composition does not contain epoxy groups or halogenated groups, the adhesion between the active layer and the current collector is poor. During battery use, the active layer in the electrode is easily separated from the current collector, resulting in faster capacity decay and deterioration of cycle performance. As shown in Comparative Example 2, when the binder in the binder composition does not contain saturated alkane units or units including epoxy groups or halogenated groups, the adhesion between the active layer and the current collector is poor, and the binder has poor flexibility, which is detrimental to the rate performance of the battery. As shown in Comparative Example 3, when the binder in the binder composition does not contain a second unit including butadiene or a third unit including epoxy groups or halogenated groups, the adhesion between the active layer and the current collector is poor, and the active layer is easily peeled off from the current collector during battery use. As shown in Comparative Example 4, when the molar content of each unit in the binder does not meet the range of this application, the cycle performance and rate performance of the obtained battery are poor.

[0192] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. An adhesive composition, wherein, The adhesive includes a first link, a second link, and a third link, wherein the first link is a link shown in Formula 1, the second link is a link shown in Formula 2, and the third link includes a link shown in Formula 3 or Formula 4. In the adhesive, the molar percentage of the first link a%, the molar percentage of the second link b%, and the molar percentage of the third link c% satisfy the following: a + b + c = 100, 80 ≤ a < 100, 0 <b≤18,0<c≤2,1<b+c≤20; R1, R2, R3, R4, and R5 are each independently selected from substituted or unsubstituted C1-C30 alkyl groups; X is a halogen.

2. The adhesive composition according to claim 1, wherein, 97≤a<99。 3. The adhesive composition according to claim 1 or 2, wherein, The number-average molecular weight of the adhesive is M n 10000≤M n ≤1,000,000; and / or, the weight-average molecular weight of the adhesive is M. w 50000≤M w ≤5000000.

4. The adhesive composition according to any one of claims 1-3, wherein, The Mooney viscosity of the adhesive is ML, 10 ≤ ML ≤ 200; and / or, The glass transition temperature of the adhesive is T. g T g ≤10℃.

5. The adhesive composition according to any one of claims 1-4, wherein, The adhesive has a tensile strength ≥ 0.1 MPa; and / or, The antioxidant potential of the adhesive is ≥4.3V.

6. The adhesive composition according to any one of claims 1-5, wherein, It also includes solvents; The dipole moment of the solvent is ≤2.5D.

7. The adhesive composition according to claim 6, wherein, The solvent is selected from at least one of xylene, butyl butyrate, decane, isobutyl isobutyrate, anisole, toluene, and isoalkanes.

8. The adhesive composition according to any one of claims 1-7, wherein, The adhesive composition contains ≤20% by mass of the adhesive.

9. The adhesive composition according to claim 8, wherein, The adhesive has a mass percentage of 5-10%.

10. An electrode sheet, wherein, The electrode includes a current collector and an active layer located on at least one surface of the current collector; The active layer comprises the adhesive composition according to any one of claims 1-9.

11. The electrode according to claim 10, wherein, The active layer also includes a sulfide electrolyte.

12. The electrode according to claim 10 or 11, wherein, The peel force between the active layer and the current collector is ≥0.01 N / cm.

13. A battery, wherein, Includes the electrode sheet as described in any one of claims 10-12.

14. A method for preparing a battery, wherein, include: An electrode assembly is obtained by stacking a positive electrode, a solid electrolyte, and a negative electrode; or, an electrode assembly is obtained by first stacking a positive electrode, a solid electrolyte, and a negative electrode, and then winding them. The battery is obtained by placing the electrode assembly in an outer package, sealing it, and then forming it. Wherein, the positive electrode and / or the negative electrode are the electrodes described in any one of claims 10-12.

15. An electronic device, wherein, Includes the battery as described in claim 13.

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