Binder composition, all-solid-state battery and preparation method of all-solid-state battery

Abstract

The invention provides a binder composition, an all-solid-state battery and a preparation method of the all-solid-state battery, and belongs to the technical field of all-solid-state battery manufacturing. The binder composition comprises a first binder, a second binder, an initiator and an organic solvent; wherein the first binder is a polymer containing alkenyl, the second binder is a saturated polymer which does not contain alkenyl and F, and the dipole moment of the organic solvent is less than or equal to 2.5 D; the binder formed by the binder composition has proper rigidity and flexibility (that is, the binder has proper buffering capacity and proper mechanical strength) and can be well matched with sulfide solid electrolyte; the problem that the functional unit corresponding to the sulfide solid electrolyte is easy to crack in the charge-discharge cycle process of the all-solid-state battery can be effectively improved, so that the corresponding all-solid-state battery has relatively excellent cycle performance.

Description

Technical Field

[0001] The present application relates to the technical field of all-solid-state battery manufacturing, and specifically to a binder composition, an all-solid-state battery, and a preparation method thereof. Background Art

[0002] At present, compared with liquid lithium-ion batteries, all-solid-state batteries with high safety and high energy density are more suitable for application scenarios such as large-scale energy storage devices. Among them, in the current research on all-solid-state batteries, sulfide solid electrolytes are one of the ideal solid electrolyte materials due to their high ionic conductivity and the ability to be densified through cold pressing. However, sulfide solid electrolytes have poor mechanical properties (high brittleness and poor ductility), resulting in poor solid-solid interface contact between them and adjacent material particles. In addition, the existing binders for sulfide solid electrolytes are difficult to achieve both appropriate rigidity and flexibility. As a result, the corresponding functional units (electrodes containing sulfide solid electrolytes, solid electrolyte membranes, etc.) are prone to cracking during the charge and discharge cycle of the all-solid-state battery, which in turn affects the cycle performance of the corresponding battery. Summary of the Invention

[0003] The purpose of the present application is to provide a binder composition, an all-solid-state battery and a preparation method thereof. The binder formed by the binder composition has both suitable rigidity and flexibility (that is, the binder has a certain buffering effect and suitable mechanical strength) and can be well adapted to the sulfide solid electrolyte. It can effectively improve the problem that the functional units corresponding to the sulfide solid electrolyte are prone to cracking during the charge and discharge cycle of the all-solid-state battery, thereby making the corresponding all-solid-state battery have relatively excellent cycle performance.

[0004] The embodiment of the present application is implemented as follows: In a first aspect, an embodiment of the present application provides an adhesive composition comprising a first adhesive, a second adhesive, an initiator, and an organic solvent; wherein the first adhesive is a polymer containing an olefinic group, the second adhesive is a saturated polymer that does not contain an olefinic group and does not contain F, and the dipole moment of the organic solvent is ≤2.5 D.

[0005] In the above technical solution, the binder composition contains a first binder, a second binder, an initiator and an organic solvent at the same time, wherein the dipole moment of the organic solvent is ≤2.5 D, that is, the organic solvent is a low-order and / or non-polar organic solvent, in order to better adapt to the sulfide solid electrolyte; the first binder is an unsaturated polymer containing an olefin group, which can be cross-linked under the action of the initiator to form a rigid three-dimensional porous skeleton to provide sufficient mechanical strength; the second binder is a saturated polymer that does not contain an olefin group and does not contain F, which has suitable flexibility and can be well dissolved and dispersed in an organic solvent. After the first binder is cross-linked to form a three-dimensional porous skeleton, the flexible second binder can be evenly distributed in the rigid skeleton. By combining an unsaturated first binder with a second binder that does not contain an olefin group and does not contain F, the binder composition ultimately forms a binder having both suitable rigidity and flexibility (i.e., the binder has a certain buffering effect and suitable mechanical strength), thereby effectively improving the problem of functional units corresponding to the sulfide solid electrolyte (electrode pieces and solid electrolyte membranes, etc.) being prone to cracking during the charge and discharge cycle of the all-solid-state battery, thereby enabling the corresponding all-solid-state battery to have relatively excellent cycle performance.

[0006] In some optional embodiments, the first binder is selected from at least one of styrene-butadiene rubber, nitrile rubber, polybutadiene rubber, natural rubber, chloroprene rubber, EPDM rubber, hydrogenated nitrile rubber, styrene-butadiene-styrene block copolymer and butyl rubber; or / and, the second binder is selected from at least one of polyisobutylene, EPDM rubber, silicone rubber, hydrogenated styrene-butadiene-styrene block copolymer, polymethyl methacrylate and polyethyl methacrylate; optionally, the organic solvent is selected from at least one of ester solvents, xylene and alkane solvents.

[0007] In the above technical solution, the first adhesive and the second adhesive are applicable to a wide variety of types, and can provide a wide variety of feasible implementation plans, thereby facilitating the promotion and application of the technical solution provided in the embodiments of the present application; furthermore, the above solvent has the advantage of good solubility, which helps to fully dissolve and evenly disperse the various components in the adhesive composition.

[0008] In some optional embodiments, the number average molecular weights of the first binder and the second binder are M n1 and M n2 , where 10000≤M n1 ≤2000000,10000≤M n2 ≤2000000; or / and, the weight average molecular weight of the first binder and the second binder are M w1 and M w2 , where 50000≤M w1 ≤10000000,50000≤Mw2 ≤10000000; Optionally, the polymer dispersion indexes of the first binder and the second binder are PDI1 and PDI2, respectively, wherein PDI1=M w1 / M n1 And 1≤PDI1≤10, PDI2=M w2 / M n2 And 1≤PDI2≤10.

[0009] In the above technical solution, the number average molecular weight, weight average molecular weight and polymer dispersion index of the first binder are respectively limited to the above ranges, so that the first binder forms a three-dimensional porous skeleton with relatively suitable rigidity after cross-linking; the number average molecular weight, weight average molecular weight and polymer dispersion index of the second binder are respectively limited to the above ranges, so that the chain segments of the second binder have relatively suitable flexibility, so as to better cooperate with the rigid three-dimensional porous skeleton.

[0010] In some optional embodiments, the Mooney viscosities of the first binder and the second binder are ML1 and ML2, respectively, wherein 10 MU≤ML1(1+4)100℃≤200 MU or / and 10 MU≤ML1(1+8)125℃≤200 MU, 10≤ML2(1+4)100℃≤200 or / and 10≤ML2(1+8)125℃≤200.

[0011] In the above technical solution, the Mooney viscosities of the first adhesive and the second adhesive are respectively limited to the above ranges, so that the first adhesive and the second adhesive both have relatively suitable viscosities.

[0012] In some optional embodiments, in the binder composition, the sum of the masses of the first binder and the second binder is M1, the mass of the organic solvent is M2, and the ratio of M1 to M2 is (5~10):(90~95); optionally, the mass of the initiator is M3, and the ratio of M1 to M3 is 100:(5~15).

[0013] In the above technical solution, the ratio of the sum of the masses of the first binder and the second binder to the mass of the organic solvent is limited to the above range, so that the organic solvent has a relatively suitable mass proportion of the binder, which helps the two binders to be more thoroughly dissolved and evenly dispersed in the organic solvent; the ratio of the sum of the masses of the first binder and the second binder to the mass of the initiator is limited to the above range, so that the organic solvent has a relatively suitable mass proportion of the initiator, which helps the first binder to be fully cross-linked to form a rigid three-dimensional porous skeleton.

[0014] In some optional embodiments, the mass ratio of the first binder to the second binder is 1:(0.3~3); optionally, the mass ratio of the first binder to the second binder is 1:1.

[0015] In the above technical solution, the mass ratio of the first binder and the second binder is limited to the above range, so that the first binder and the second binder have an appropriate mass ratio, so that the final binder has both more appropriate rigidity and flexibility, so as to more effectively improve the problem that the functional units (pole pieces and solid electrolyte membranes) corresponding to the sulfide solid electrolyte are prone to cracking during the charge and discharge cycle of the all-solid-state battery; further, the mass ratio of the first binder and the second binder is limited to 1:1, so that the final binder has both more appropriate rigidity and flexibility, so as to more effectively improve the problem that the functional units (pole pieces and solid electrolyte membranes) corresponding to the sulfide solid electrolyte are prone to cracking during the charge and discharge cycle of the all-solid-state battery.

[0016] In some optional embodiments, the binder composition further comprises a lithium salt; optionally, the mass of the lithium salt is M4, and the ratio of M1 to M4 is 10:(0.5~1).

[0017] In the above technical solution, lithium salt is added to the binder composition so that the final binder also contains lithium salt, which helps to improve the cycle performance and capacity of the corresponding battery; further, the ratio of the sum of the mass of the first binder and the second binder to the mass of the lithium salt is limited to the above range so that the final binder contains an appropriate amount of lithium salt, which helps to better improve the cycle performance and capacity of the corresponding battery.

[0018] In a second aspect, an embodiment of the present application provides an all-solid-state battery, comprising a positive electrode sheet, a solid electrolyte membrane and a negative electrode sheet stacked in sequence, at least one of the positive electrode sheet, the solid electrolyte membrane and the negative electrode sheet comprises a sulfide solid electrolyte and a binder, wherein the binder is formed by cross-linking the binder composition provided in the embodiment of the first aspect after removing the organic solvent.

[0019] In the above technical solution, the all-solid-state battery includes a positive electrode sheet, a solid electrolyte membrane and a negative electrode sheet stacked in sequence, and at least one of the positive electrode sheet, the solid electrolyte membrane and the negative electrode sheet includes a sulfide solid electrolyte and a binder, wherein the binder is formed by cross-linking the binder composition provided in the first embodiment after removing the organic solvent. Since the binder formed by the final cross-linking of the binder composition has both relatively suitable rigidity and flexibility, it can effectively improve the problem that the functional unit containing the sulfide solid electrolyte is prone to cracking during the charge and discharge cycle of the corresponding all-solid-state battery, so that the corresponding battery has relatively excellent cycle performance. In particular, when the negative electrode sheet contains the binder formed by cross-linking the binder composition provided in the first embodiment after removing the organic solvent, since the binder does not contain F, it can also effectively improve the problem that the negative electrode interface stability becomes poor and lithium dendrites are easily generated after the corresponding negative electrode sheet contacts the F-containing binder (when the negative electrode sheet is lithium-intercalated, it contacts the F-containing binder to generate conductive sp 2 Carbon deteriorates the interface stability and makes lithium dendrites more likely to form).

[0020] In some optional embodiments, the positive electrode active material in the positive electrode sheet is selected from nickel-cobalt-manganese ternary positive electrode material, and the negative electrode active material in the negative electrode sheet is selected from at least one of silicon, graphite, silicon-carbon and silicon-graphite composite.

[0021] In the above technical solutions, there are many systems of active materials that can be adapted in all-solid-state batteries, which can provide more feasible implementation plans, thereby facilitating the promotion and application of the technical solutions provided in the embodiments of this application.

[0022] In a third aspect, an embodiment of the present application provides a method for preparing an all-solid-state battery as provided in an embodiment of the second aspect, comprising the following steps: stacking a positive electrode sheet, a solid electrolyte membrane, and a negative electrode sheet in sequence to form an electrode assembly, wherein at least one of the positive electrode sheet, the solid electrolyte membrane, and the negative electrode sheet comprises a sulfide solid electrolyte and a binder composition after removing the organic solvent; and performing isostatic pressing and cross-linking treatment on the electrode assembly to obtain an all-solid-state battery.

[0023] In the above technical solution, by preparing according to the above process, an all-solid-state battery with relatively excellent cycle performance as provided in the embodiment of the second aspect can be prepared.

[0024] In some optional embodiments, the positive electrode sheet, the solid electrolyte membrane, and the negative electrode sheet all include a sulfide solid electrolyte and a binder composition after removing the organic solvent; and the preparation method includes the following steps: The raw materials of the positive electrode sheet and the binder composition are mixed to form a positive electrode slurry, and the positive electrode slurry is coated on the positive electrode collector and dried to remove the organic solvent to obtain the positive electrode sheet; the raw materials of the negative electrode sheet and the binder composition are mixed to form a negative electrode slurry, and the negative electrode slurry is coated on the negative electrode collector and dried to remove the organic solvent to obtain the negative electrode sheet; the raw materials of the solid electrolyte membrane and the binder composition are mixed to form a solid electrolyte membrane slurry; the solid electrolyte membrane slurry is respectively coated on the surface of the positive electrode sheet and the negative electrode sheet and dried to remove the organic solvent to form a first solid electrolyte membrane on the surface of the positive electrode sheet to obtain a composite positive electrode sheet; and a second solid electrolyte membrane is formed on the surface of the negative electrode sheet to obtain a composite negative electrode sheet; the composite positive electrode sheet and the composite negative electrode sheet are stacked and assembled so that the first solid electrolyte membrane and the second solid electrolyte membrane are in contact to obtain an electrode assembly; the electrode assembly is isostatically pressed and cross-linked to obtain an all-solid-state battery.

[0025] In the above technical solution, when the positive electrode sheet, the solid electrolyte membrane and the negative electrode sheet all include a sulfide solid electrolyte and the binder composition provided by the embodiment of the first aspect after removing the organic solvent, they are prepared according to the above process, that is, after the positive electrode sheet, the solid electrolyte membrane and the negative electrode sheet are stacked and assembled, they are uniformly cross-linked, so that the formed binder with both appropriate rigidity and flexibility is uniformly distributed on the surface and interior of the electrode sheet and the surface and interior of the solid electrolyte membrane (the binder with both rigidity and flexibility has a certain buffering effect and mechanical strength, can better adapt to the volume changes of the materials in each region, and ensure the electrode sheet and The invention can improve the consistency and uniformity of the distribution of solid substances inside the solid electrolyte membrane, and can also prevent lithium dendrites from piercing the solid electrolyte membrane); at the same time, the solid electrolyte membrane and the electrode are prepared into a composite electrode (i.e., a composite positive electrode and a composite negative electrode) and then cross-linked at one time, which can also make the formed binder have good continuity, and help to improve the solid-solid interface contact between the positive electrode, the negative electrode and the solid electrolyte membrane, thereby making the prepared all-solid-state battery electrode and solid electrolyte membrane have the advantage of not being easy to crack during the charge and discharge cycle, that is, the corresponding all-solid-state battery has more excellent cycle performance.

[0026] In some optional embodiments, in the cross-linking step, the treatment temperature is 120-180° C. and the treatment time is 2-8 h.

[0027] In the above technical solution, the temperature and time in the cross-linking treatment step are respectively limited to the above ranges, so that the first binder can be fully cross-linked to form a rigid three-dimensional porous skeleton, and also so that the prepared electrode and solid electrolyte membrane have more suitable flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 A process flow chart of a method for preparing an all-solid-state battery provided in an embodiment of the present application. DETAILED DESCRIPTION

[0030] To make the purpose, technical solutions and advantages of the examples of the present application clearer, the technical solutions in the examples of the present application will be described clearly and completely below. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0031] It should be noted that “and / or” in this application, such as “Feature 1 and / or Feature 2”, refers to three situations: “Feature 1” alone, “Feature 2” alone, or “Feature 1” plus “Feature 2”.

[0032] In addition, in the description of this application, unless otherwise specified, the "multiple" in "one or more" means two or more; the range of "value a~value b" includes the two end values ​​"a" and "b", and the "unit of measurement" in "value a~value b+unit of measurement" represents the "unit of measurement" of both "value a" and "value b".

[0033] In the prior art, the functional units (pole pieces and solid electrolyte membranes) corresponding to sulfide solid electrolytes are prone to cracking during the charge and discharge cycles of all-solid-state batteries. The inventors have discovered that the possible reasons for this tendency are as follows: (1) For the pole piece, it contains active material particles, sulfide solid electrolyte particles and conductive agent and other particle components. The sulfide solid electrolyte particles have poor mechanical properties (the material is highly brittle and has poor ductility). In addition, the active material particles undergo a certain degree of volume change during the battery charging and discharging process. At the same time, the existing binders suitable for sulfide solid electrolytes are difficult to have both appropriate rigidity and flexibility, which makes it easy for the various particle components in the pole piece to disconnect during the charging and discharging process, thereby forming defects such as tiny pores inside the pole piece. After a long cycle, these internal defects will expand, which will cause the pole piece to easily break.

[0034] (2) For the solid electrolyte membrane, the solid electrolyte membrane contains a large number of sulfide solid electrolyte particles with poor mechanical properties, which makes the solid electrolyte membrane as a whole relatively brittle and poorly ductile. In addition, the volume change of the electrode during the charge and discharge process is certain. Since the solid electrolyte membrane is difficult to adapt to the volume change of the electrode, the solid electrolyte membrane is easy to break under stress. In addition, there are certain pores inside the solid electrolyte membrane. At the interface in contact with the negative electrode side, lithium dendrites formed by lithium insertion on the negative electrode side are easy to grow in defects such as pores in the electrolyte membrane. The existing binders suitable for sulfide solid electrolytes are difficult to have both appropriate rigidity and flexibility, making the electrolyte membrane insufficient to resist the penetration of lithium dendrites. Frequent lithium removal and lithium insertion during the cycle cause the electrolyte membrane to be penetrated by lithium dendrites and form cracks, which can also easily lead to the rupture of the solid electrolyte membrane.

[0035] Based on this, the inventors provide a binder composition that forms a binder with both suitable rigidity and flexibility (i.e., the binder possesses a certain buffering effect and suitable mechanical strength) and is well compatible with sulfide solid electrolytes. This effectively alleviates the problem of functional units corresponding to the sulfide solid electrolyte being susceptible to cracking during the charge and discharge cycles of all-solid-state batteries, thereby enabling the corresponding all-solid-state batteries to have relatively excellent cycle performance. A binder composition, all-solid-state battery, and preparation method thereof according to an embodiment of the present application are described in detail below.

[0036] In a first aspect, an embodiment of the present application provides an adhesive composition comprising a first adhesive, a second adhesive, an initiator, and an organic solvent; wherein the first adhesive is a polymer containing an olefinic group, the second adhesive is a saturated polymer that does not contain an olefinic group and does not contain F, and the dipole moment of the organic solvent is ≤2.5 D.

[0037] In the present application, the binder composition contains a first binder, a second binder, an initiator, and an organic solvent, wherein the dipole moment of the organic solvent is ≤2.5 D, that is, the organic solvent is a low-order and / or non-polar organic solvent, in order to better adapt to the sulfide solid electrolyte; the first binder is an unsaturated polymer containing an olefinic group, which can be cross-linked under the action of the initiator to form a rigid three-dimensional porous skeleton to provide sufficient mechanical strength; the second binder is a saturated polymer without an olefinic group and without F, which has suitable flexibility and can be well dissolved and dispersed in the organic solvent. After the first binder is cross-linked to form a three-dimensional porous skeleton, the flexible second binder can be evenly distributed in the rigid skeleton. By the mutual cooperation of the unsaturated first binder and the second binder without an olefinic group and without F, the binder finally formed by the binder composition has both suitable rigidity and flexibility (that is, the binder has a certain buffering effect and suitable mechanical strength), thereby effectively improving the problem that the functional units (electrode and solid electrolyte membrane) corresponding to the sulfide solid electrolyte are prone to cracking during the charge and discharge cycle of the all-solid-state battery, thereby making the corresponding all-solid-state battery have relatively excellent cycle performance.

[0038] Specifically, for the electrode, the binder has both appropriate rigidity and flexibility (that is, the binder has a certain buffering effect and appropriate mechanical strength), so that the electrode can better adapt to the volume changes of various materials inside the electrode during the charge and discharge cycle of the all-solid-state battery, and improve the problem of defects easily generated inside the electrode, which may lead to electrode rupture.

[0039] For solid electrolyte membranes, the binder has both appropriate rigidity and flexibility (that is, the binder has a certain buffering effect and appropriate mechanical strength), so that the solid electrolyte membrane has both appropriate strength and ductility, so that it can adapt to the volume changes of the electrode and effectively block lithium dendrites, thereby improving the problem of easy cracking of the solid electrolyte membrane.

[0040] It should be noted that, in addition to the adhesive having suitable rigidity and flexibility, the adhesive composition provided in the embodiments of the present application also has the following advantages: the raw materials of the adhesive are all polymers, and the adhesive with a three-dimensional porous structure finally formed is achieved by polymer cross-linking. Compared with the method of using small molecule monomers to polymerize to form large molecule adhesives in the prior art (small molecule monomer polymerization has the defect of uncontrollable polymerization degree), the technical solution provided in the embodiments of the present application has the advantage that the molecular weight of the adhesive formed is relatively controllable.

[0041] As an example, the first binder is selected from at least one of styrene-butadiene rubber, nitrile rubber, polybutadiene rubber, natural rubber, chloroprene rubber, EPDM rubber, hydrogenated nitrile rubber, styrene-butadiene-styrene block copolymer and butyl rubber; or / and, the second binder is selected from at least one of polyisobutylene, EPDM rubber, silicone rubber, hydrogenated styrene-butadiene-styrene block copolymer, polymethyl methacrylate and polyethyl methacrylate.

[0042] In this embodiment, the first adhesive and the second adhesive are applicable to a wide variety of types, and can provide a wide variety of feasible implementation plans, thereby facilitating the promotion and application of the technical solutions provided in the embodiments of the present application.

[0043] As an example, the organic solvent is selected from at least one of an ester solvent, xylene, and an alkane solvent. In this embodiment, the above solvent has the advantage of good solubility, which helps to fully dissolve and evenly disperse the various components in the binder composition.

[0044] As an example, the organic solvent is selected from ester solvents.

[0045] In this embodiment, the ester solvent has the advantages of good solubility, good stability and relatively safe. It should be noted that the type of ester solvent is not limited, and for example, it can be at least one of butyl butyrate, isobutyl isobutyrate, benzyl acetate, ethyl octanoate, and nonyl acetate.

[0046] As an example, the alkane solvent is selected from at least one of decane, heptane and dodecane.

[0047] As an example, the number average molecular weights of the first binder and the second binder are M n1 and M n2 , where 10000≤M n1 ≤2000000,10000≤M n2 ≤2000000; or / and, the weight average molecular weight of the first binder and the second binder are M w1 and M w2 , where 50000≤M w1 ≤10000000,50000≤M w2 ≤10000000.

[0048] It should be noted that the number average molecular weights of the first binder and the second binder may be the same or different; similarly, the weight average molecular weights of the first binder and the second binder may be the same or different.

[0049] As an example, the polymer dispersion indexes of the first binder and the second binder are PDI1 and PDI2, respectively, wherein PDI1=Mw1 / M n1 And 1≤PDI1≤10, PDI2=M w2 / M n2 And 1≤PDI2≤10.

[0050] It should be noted that the polymer dispersion indexes of the first binder and the second binder may be the same or different.

[0051] In this embodiment, the number average molecular weight, weight average molecular weight and polymer dispersion index of the first binder are respectively limited to the above ranges, so that the first binder forms a three-dimensional porous skeleton with relatively suitable rigidity after cross-linking; the number average molecular weight, weight average molecular weight and polymer dispersion index of the second binder are respectively limited to the above ranges, so that the chain segments of the second binder have relatively suitable flexibility, so as to better cooperate with the rigid three-dimensional porous skeleton.

[0052] As an example, the Mooney viscosities of the first binder and the second binder are ML1 and ML2, respectively, wherein 10 MU≤ML1(1+4)100℃≤200 MU or / and 10 MU≤ML1(1+8)125℃≤200 MU, 10 MU≤ML2(1+4)100℃≤200 MU or / and 10 MU≤ML2(1+8)125℃≤200 MU.

[0053] It should be noted that the Mooney viscosities of the first adhesive and the second adhesive may be the same or different.

[0054] To better understand Mooney viscosity, its meaning is explained here in conjunction with ML(1+4)100℃, where M represents the Mooney viscosity value, L indicates the use of a large rotor during the test, 1 indicates a preheating phase of 1 minute, 4 indicates a test duration of 4 minutes during which the rotor officially rotates, and 100℃ indicates that the entire test process is carried out at a constant temperature of 100℃. ML(1+4)100℃ means: at a constant temperature of 100°C, place the sample in the test chamber of the Mooney viscometer and preheat it for 1 minute, then start the large rotor to rotate for 4 minutes, and read the Mooney viscosity value at the end of 4 minutes of rotation.

[0055] In this embodiment, the Mooney viscosities of the first adhesive and the second adhesive are respectively limited to the above ranges, so that both the first adhesive and the second adhesive have relatively suitable viscosities.

[0056] As an example, in the adhesive composition, the sum of the masses of the first adhesive and the second adhesive is M1, the mass of the organic solvent is M2, and the ratio of M1 to M2 is (5-10): (90-95), for example, but not limited to, any one of 5:95, 6:94, 7:93, 8:92, 9:91 and 10:90, or a range between any two of the ratios.

[0057] In this embodiment, the ratio of the sum of the masses of the first binder and the second binder to the mass of the organic solvent is limited to the above range, so that the organic solvent contains a binder with a relatively appropriate mass ratio, which helps the two binders to be more thoroughly dissolved and evenly dispersed in the organic solvent.

[0058] As an example, the mass of the initiator is M3, and the ratio of M1 to M3 is 100:(5~15), for example, but not limited to, any one of 100:5, 100:8, 100:10, 100:12 and 100:15, or a range of values ​​between any two of them.

[0059] In this embodiment, the ratio of the sum of the masses of the first binder and the second binder to the mass of the initiator is limited to the above range, so that the organic solvent contains a relatively suitable mass proportion of the initiator, thereby helping the first binder to fully cross-link to form a rigid three-dimensional porous skeleton.

[0060] It should be noted that the type of initiator is not limited, for example, it can be at least one of a sulfur cross-linking system and an azo initiator. In the embodiment of the present application, the sulfur cross-linking system is taken as an example.

[0061] It is understandable that the specific composition of the sulfur cross-linking system is not limited and can be set according to conventional selection in the field. For example, the initiator of the sulfur cross-linking system includes sulfur, zinc oxide, mercaptobenzothiazole and stearic acid in a mass ratio of 2:2:5:1.

[0062] It should be noted that the mass ratio of the first binder to the second binder is not limited and can be adaptively adjusted according to actual needs so that the corresponding electrode or solid electrolyte membrane has both appropriate rigidity and flexibility.

[0063] As an example, the mass ratio of the first binder to the second binder is 1:(0.3~3), for example, but not limited to, any one of 1:0.3, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5 and 1:3 or a range between any two of them.

[0064] In this embodiment, the mass ratio of the first binder and the second binder is limited to the above range so that the first binder and the second binder have an appropriate mass ratio, so that the finally formed binder has both relatively suitable rigidity and flexibility, so as to more effectively improve the problem that the functional units (electrode pieces and solid electrolyte membranes) corresponding to the sulfide solid electrolyte are prone to cracking during the charge and discharge cycle of the all-solid-state battery.

[0065] As an example, the mass ratio of the first binder to the second binder is 1:1.

[0066] In this embodiment, the mass ratio of the first binder to the second binder is limited to 1:1, so that the final binder has more suitable rigidity and flexibility, so as to more effectively improve the problem that the functional units (electrode pieces and solid electrolyte membranes) corresponding to the sulfide solid electrolyte are prone to cracking during the charge and discharge cycle of the all-solid-state battery.

[0067] As an example, the binder composition further includes a lithium salt.

[0068] In this embodiment, lithium salt is added to the binder composition so that the final binder also contains lithium salt, which helps to improve the cycle performance and capacity of the corresponding battery.

[0069] It should be noted that the type of lithium salt is not limited, and for example, it can be at least one of lithium bis(trifluoromethanesulfonyl)imide and lithium hexafluorophosphate.

[0070] As an example, the mass of the lithium salt is M4, and the ratio of M1 to M4 is 10:(0.5~1), for example, but not limited to, any one of 10:0.5, 10:0.6, 10:0.7, 10:0.8, 10:0.9 and 10:1, or a range between any two of the ratios.

[0071] In this embodiment, the ratio of the sum of the masses of the first binder and the second binder to the mass of the lithium salt is limited to the above range, so that the final binder contains an appropriate amount of lithium salt, which helps to better improve the cycle performance and capacity of the corresponding battery.

[0072] It should be noted that the functional components not specifically described or limited in the adhesive composition may be arranged according to conventional selection in the art.

[0073] In a second aspect, an embodiment of the present application provides an all-solid-state battery, comprising a positive electrode sheet, a solid electrolyte membrane and a negative electrode sheet stacked in sequence, at least one of the positive electrode sheet, the solid electrolyte membrane and the negative electrode sheet comprises a sulfide solid electrolyte and a binder, wherein the binder is formed by cross-linking the binder composition provided in the embodiment of the first aspect after removing the organic solvent.

[0074] In the present application, the all-solid-state battery includes a positive electrode sheet, a solid electrolyte membrane and a negative electrode sheet stacked in sequence, and at least one of the positive electrode sheet, the solid electrolyte membrane and the negative electrode sheet includes a sulfide solid electrolyte and a binder, wherein the binder is formed by cross-linking the binder composition provided in the first embodiment after removing the organic solvent. Since the binder formed by the final cross-linking of the binder composition has relatively suitable rigidity and flexibility, it can effectively improve the problem that the functional unit containing the sulfide solid electrolyte is prone to cracking during the corresponding all-solid-state battery charge and discharge cycle, so that the corresponding battery has relatively excellent cycle performance.

[0075] In particular, when the negative electrode sheet contains a binder formed by cross-linking the binder composition provided by the first embodiment after removing the organic solvent, since the binder does not contain F, it can also effectively improve the problem of poor interface stability of the negative electrode and the easy occurrence of lithium dendrites after the corresponding negative electrode sheet contacts the F-containing binder (when the negative electrode sheet is lithium-intercalated, contact with the F-containing binder will generate conductive sp 2 Carbon deteriorates the interface stability and makes lithium dendrites more likely to form).

[0076] As an example, the positive electrode sheet, the solid electrolyte membrane, and the negative electrode sheet all include a sulfide solid electrolyte and a binder.

[0077] In this embodiment, the positive electrode sheet, the solid electrolyte membrane and the negative electrode sheet all include a sulfide solid electrolyte and a binder, so that the material systems of the electrode sheet and the solid electrolyte membrane are relatively close and both have appropriate rigidity and flexibility, thereby more effectively improving the problem of the functional unit containing the sulfide solid electrolyte being prone to cracking during the corresponding all-solid-state battery charge and discharge cycle, so that the corresponding battery has better cycle performance.

[0078] It should be noted that the types of active materials used in the positive electrode sheet and the negative electrode sheet are not limited and can be adaptively adjusted according to actual needs.

[0079] As an example, the sulfide solid electrolyte is selected from Li 10 GeP2S 12 At least one of a sulfide solid electrolyte, a Thio-LISICON sulfide solid electrolyte and an Argentite sulfide solid electrolyte, for example, a sulfide solid electrolyte selected from Li6PS5Cl, Li 5.5 PS 4.5 Cl 1.5 , Li2SP2S5-LiX (X is Cl, Br or I), Li2S-P2S5-X2 (X=Cl, Br or I), Li3PS4 and Li2S-P2S5.

[0080] As an example, the positive electrode active material in the positive electrode sheet is selected from nickel-cobalt-manganese ternary positive electrode material, and the negative electrode active material in the negative electrode sheet is selected from at least one of silicon, graphite, silicon-carbon and silicon-graphite composite.

[0081] In this embodiment, there are many systems of active materials that can be adapted in the all-solid-state battery, which can provide more feasible implementation plans, thereby facilitating the promotion and application of the technical solutions provided in the embodiments of this application.

[0082] It should be noted that any functional unit not specifically described or limited in the all-solid-state battery may be configured according to conventional selections in the art.

[0083] In a third aspect, an embodiment of the present application provides a method for preparing an all-solid-state battery as provided in an embodiment of the second aspect, comprising the following steps: stacking a positive electrode sheet, a solid electrolyte membrane, and a negative electrode sheet in sequence to form an electrode assembly, wherein at least one of the positive electrode sheet, the solid electrolyte membrane, and the negative electrode sheet comprises a sulfide solid electrolyte and a binder composition after removing the organic solvent; and performing isostatic pressing and cross-linking treatment on the electrode assembly to obtain an all-solid-state battery.

[0084] In the present application, by preparing according to the above process, an all-solid-state battery with relatively excellent cycle performance as provided in the second embodiment can be prepared.

[0085] In other possible implementations, the functional unit containing the sulfide solid electrolyte and the binder composition may be cross-linked and then assembled with other functional units to obtain an electrode assembly.

[0086] As an example, the positive electrode sheet, the solid electrolyte membrane, and the negative electrode sheet all include a sulfide solid electrolyte and the binder composition provided in the embodiment of the first aspect after removing the organic solvent; the preparation method includes the following steps: The raw materials of the positive electrode sheet and the binder composition are mixed to form a positive electrode slurry, and the positive electrode slurry is coated on the positive electrode collector and dried to remove the organic solvent to obtain the positive electrode sheet; the raw materials of the negative electrode sheet and the binder composition are mixed to form a negative electrode slurry, and the negative electrode slurry is coated on the negative electrode collector and dried to remove the organic solvent to obtain the negative electrode sheet; the raw materials of the solid electrolyte membrane and the binder composition are mixed to form a solid electrolyte membrane slurry; the solid electrolyte membrane slurry is respectively coated on the surface of the positive electrode sheet and the negative electrode sheet and dried to remove the organic solvent to form a first solid electrolyte membrane on the surface of the positive electrode sheet to obtain a composite positive electrode sheet; and a second solid electrolyte membrane is formed on the surface of the negative electrode sheet to obtain a composite negative electrode sheet; the composite positive electrode sheet and the composite negative electrode sheet are stacked and assembled so that the first solid electrolyte membrane and the second solid electrolyte membrane are in contact to obtain an electrode assembly; the electrode assembly is isostatically pressed and cross-linked to obtain an all-solid-state battery.

[0087] In this embodiment, when the positive electrode sheet, the solid electrolyte membrane and the negative electrode sheet all include a sulfide solid electrolyte and a binder composition as provided in the embodiment of the first aspect after removing the organic solvent, they are prepared according to the above process, that is, after the positive electrode sheet, the solid electrolyte membrane and the negative electrode sheet are stacked and assembled, they are uniformly cross-linked, so that the formed binder with both suitable rigidity and flexibility is uniformly distributed on the surface and interior of the electrode sheet and the surface and interior of the solid electrolyte membrane (the binder with both rigidity and flexibility has a certain buffering effect and mechanical strength, can better adapt to the volume changes of the materials in each region, and ensure the electrode sheet and the consistency and uniformity of the distribution of various solid substances inside the solid electrolyte membrane, and can also prevent lithium dendrites from piercing the solid electrolyte membrane); at the same time, the solid electrolyte membrane and the electrode are prepared into a composite electrode (i.e., a composite positive electrode and a composite negative electrode) together and then cross-linked at one time, which can also make the formed binder have good continuity, and help to improve the interface contact between the positive electrode, the negative electrode and the solid electrolyte membrane, thereby making the prepared all-solid-state battery electrode and solid electrolyte membrane have the advantage of not being easy to crack during the charge and discharge cycle, that is, the corresponding all-solid-state battery has more excellent cycle performance.

[0088] It should be noted that the preparation process provided in the embodiment of the present application only performs a cross-linking treatment once. Compared with the preparation process that adopts a step-by-step cross-linking treatment, that is, first preparing the positive electrode sheet, solid electrolyte membrane and negative electrode sheet respectively through cross-linking treatment, and then assembling the three, the preparation process provided in the embodiment of the present application has the advantages of better continuity of the binder formed by cross-linking and a simpler process.

[0089] It should be noted that the preparation of the positive electrode slurry, the negative electrode slurry and the solid electrolyte membrane slurry can be carried out simultaneously or sequentially, and can be adaptively adjusted according to actual needs.

[0090] As an example, the step of mixing the raw materials of the positive electrode sheet and the binder composition to form a positive electrode slurry includes: mixing, by weight, 70-90 parts of the positive electrode active material, 10-30 parts of the sulfide solid electrolyte, 0.5-5 parts of the conductive agent, and 0.5-5 parts of the binder composition (it should be noted that the mass of the binder composition refers to the mass excluding the solvent and initiator, that is, the sum of the masses of the first binder and the second binder, M1, represents the mass of the entire binder composition) to obtain the positive electrode slurry. It should be noted that during the preparation of the positive electrode slurry, an organic solvent with a dipole moment ≤ 2.5 D may be added as needed to better disperse the various components.

[0091] As an example, the step of mixing the raw materials of the negative electrode sheet and the binder composition to form a negative electrode slurry includes: mixing, by weight, 50 to 80 parts of the negative electrode active material, 20 to 50 parts of the sulfide solid electrolyte, 1 to 5 parts of the conductive agent and 1 to 5 parts of the binder composition (it should be noted that the mass of the binder composition refers to the mass excluding the solvent and the initiator, that is, the sum of the masses of the first binder and the second binder M1 represents the mass of the entire binder composition) to obtain a positive electrode slurry.

[0092] It should be noted that, in the process of preparing the negative electrode slurry, in order to better disperse the various components, an organic solvent with a dipole moment ≤ 2.5 D may be added as needed.

[0093] As an example, the step of mixing the raw materials of the solid electrolyte membrane and the binder composition to form a solid electrolyte membrane slurry includes: mixing 90 to 99 parts of a sulfide solid electrolyte and 1 to 10 parts of a binder composition in parts by mass (it should be noted that the mass of the binder composition refers to the mass excluding the solvent and the initiator, that is, the sum of the masses of the first binder and the second binder M1 represents the mass of the entire binder composition) to obtain a solid electrolyte membrane slurry.

[0094] It should be noted that, in the process of preparing the solid electrolyte membrane slurry, in order to better disperse the various components, an organic solvent with a dipole moment ≤ 2.5 D may be added as needed.

[0095] It should be noted that, before mixing the adhesive composition with various raw materials, the adhesive composition may be stirred in advance to improve the uniformity of the adhesive composition.

[0096] As an example, in the cross-linking treatment step, the treatment temperature is 120~180℃, for example but not limited to the temperature of any one of 120℃, 130℃, 140℃, 150℃, 160℃, 170℃ and 180℃, or a range between any two of them; the treatment time is 2~8 h, for example but not limited to the treatment time of any one of 2 h, 3 h, 4 h, 5 h, 6 h, 7 h and 8 h, or a range between any two of them.

[0097] In this embodiment, the temperature and time in the cross-linking treatment step are respectively limited to the above ranges, so that the first binder can be fully cross-linked to form a rigid three-dimensional porous skeleton, and also so that the prepared electrode and solid electrolyte membrane have more suitable flexibility.

[0098] It should be noted that any process or step not specifically described or limited in the preparation of all-solid-state batteries may be arranged according to conventional selections in the art.

[0099] As an example, the process flow chart of the preparation method of the all-solid-state battery is shown in FIG. Figure 1 .

[0100] The features and performance of the present application are further described in detail below with reference to the embodiments.

[0101] Example 1 The present invention provides a method for preparing an all-solid-state battery, comprising the following steps: S1. Providing an adhesive composition, specifically comprising: 0.5 g of acrylonitrile-butadiene rubber (Mooney viscosity ML(1+4) at 100°C of 70 MU, polymer dispersion index of 5, number average molecular weight of 200,000, and weight average molecular weight of 1,000,000) and polyisobutylene (Mooney viscosity ML(1+4) at 100°C of 50 MU, polymer dispersion index of 3, number average molecular weight of 100,000, and weight average molecular weight of 500,000) with a total mass ratio of 25:75, 9.5 g of butyl butyrate, and 0.05 g of an initiator for a sulfur crosslinking system (comprising sulfur, zinc oxide, mercaptobenzothiazole, and stearic acid in a mass ratio of 2:2:5:1, respectively); stirring and mixing the adhesive composition for later use.

[0102] S2 According to the mass fraction, 85 parts of positive electrode active material (NCM811), sulfide solid electrolyte (Li 5.5 PS 4.5 Cl 1.5 ), 15 parts of a conductive agent (conductive carbon black), 1 part of the above-mentioned binder composition (it should be noted that the mass of the binder composition refers to the mass without solvent and initiator, that is, the sum of the masses of the first binder and the second binder M1 represents the mass of the entire binder composition), and 0.6 g of butyl butyrate are stirred and mixed to obtain a positive electrode slurry; then the positive electrode slurry is scraped (with a thickness of 150 μm) on an aluminum foil and dried (dried at 60°C for 30 min) to remove the organic solvent to obtain a positive electrode sheet.

[0103] S3 According to the mass fraction, 70 parts of negative electrode active material (graphite), sulfide solid electrolyte (Li 5.5 PS 4.5 Cl 1.5), 30 parts of a conductive agent (conductive carbon black), 2 parts of the above-mentioned binder composition (it should be noted that the mass of the binder composition refers to the mass excluding the solvent and the initiator, that is, the sum of the masses of the first binder and the second binder M1 represents the mass of the entire binder composition), and 0.6 g of butyl butyrate were stirred and mixed to obtain a negative electrode slurry; then the negative electrode slurry was scraped (with a thickness of 50 μm) on a copper foil and dried (dried at 60°C for 30 min) to remove the organic solvent to obtain a negative electrode sheet.

[0104] S4 is calculated by weight, and the sulfide solid electrolyte (Li 5.5 PS 4.5 Cl 1.5 ), 95 parts of a binder composition (it should be noted that the mass of the binder composition refers to the mass excluding the solvent and the initiator, that is, the sum of the masses of the first binder and the second binder M1 represents the mass of the entire binder composition), and 100 parts of butyl butyrate are stirred and mixed to obtain a solid electrolyte membrane slurry; the solid electrolyte membrane slurry is respectively coated on the surface of the positive electrode sheet and the negative electrode sheet (the coating thickness is 150 μm) and dried to remove the organic solvent, so as to form a first solid electrolyte membrane on the surface of the positive electrode sheet to obtain a composite positive electrode sheet; and a second solid electrolyte membrane is formed on the surface of the negative electrode sheet to obtain a composite negative electrode sheet.

[0105] S5: stacking and assembling the composite positive electrode sheet and the composite negative electrode sheet so that the first solid electrolyte membrane contacts the second solid electrolyte membrane to obtain an electrode assembly.

[0106] S6 The electrode assembly was subjected to isostatic pressing (pressure of 450 MPa, processing time of 30 min) and cross-linking treatment (processing temperature of 150 ° C, processing time of 8 h) to obtain an all-solid-state battery.

[0107] The subsequent examples and comparative examples were prepared according to the steps of Example 1. In order to better understand the parameter differences between the examples and comparative examples, they are summarized in the form of a table below. For details, please refer to Table 1.

[0108] Table 1

[0109] It should be noted that “—” in Table 1 means none; in addition, in Comparative Example 4, only replacing the second binder with F-containing polyvinylidene fluoride cannot produce a uniform and stable all-solid-state battery. The reason is that: nitrile rubber and polyvinylidene fluoride have different solubilities in solvents such as butyl butyrate, and the solubility of polyvinylidene fluoride is relatively low, resulting in uneven glue liquid of the mixture of the two. During the wet slurry coating and drying process, migration problems of the two binders will occur, and the prepared positive and negative electrode sheets and electrolyte membranes will be uneven. In particular, during the preparation of the electrolyte membrane, the floating and stratification of the binder will lead to uneven electrolyte slurry and poor particle dispersion, which will result in different binder compositions and uneven surfaces on the front and back sides of the electrolyte membrane, making it impossible to use it for the preparation of all-solid-state batteries.

[0110] Test example The all-solid-state batteries prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were numbered respectively, and then the first discharge capacity (mAh / g), rate performance (0.5C / 0.1C) and capacity retention rate after 200 cycles at 0.5C of each sample were tested, and the test results were statistically summarized in Table 2.

[0111] The test steps for the first discharge capacity are as follows: At 25°C, the battery was charged to 4.25 V at a constant current of 0.1 C, then discharged to 1.2 V at a constant current of 0.1 C, and then left to stand for 5 minutes. This was a charge and discharge cycle, and the discharge capacity was recorded as the discharge capacity of the battery in the first cycle.

[0112] The test steps for rate performance are as follows: The above batteries were tested for constant current charge and discharge using the BlueDian battery test system CT2001A at 25°C. The specific steps are as follows: Step 1: Charge at 0.1C constant current to the cut-off voltage, let it stand for 2 minutes, discharge at 0.1C constant current to the termination voltage, let it stand for 2 minutes.

[0113] Step 2: Charge with 0.2C constant current to the cut-off voltage, and discharge with 0.2C constant current to the termination voltage.

[0114] Step 3: Charge with 0.5C constant current to the cut-off voltage, and discharge with 0.5C constant current to the termination voltage.

[0115] The rate performance data is the ratio of the 0.5C discharge capacity to the 0.1C discharge capacity.

[0116] The test steps for capacity retention are as follows: A charge-discharge cycle consists of charging at a constant current of 0.5C to the cutoff voltage and discharging at a constant current of 0.5C to the cutoff voltage. The discharge capacity is the discharge capacity of the first cycle. The battery cells are subjected to multiple charge-discharge cycles as described above. The discharge capacity at the 200th cycle is measured and the post-cycle capacity retention of the battery cells is calculated using the following formula. Capacity retention after 200 cycles (%) = [Discharge capacity at the 200th cycle / Discharge capacity at the first cycle] × 100%.

[0117] Table 2

[0118] Referring to Table 2, the test results of Examples 1 to 6 and Comparative Examples 1 to 2 show that the binder composition contains both the first binder and the second binder provided in the examples of the present application. Compared with the binder composition containing only one of the binders, the all-solid-state battery prepared in the former has better cycle performance, discharge capacity, and rate performance.

[0119] From the test results of Example 2 and Example 6, it can be seen that adding an appropriate amount of lithium salt to the binder composition can further improve the cycle performance, discharge capacity and rate performance of the corresponding all-solid-state battery.

[0120] From the test results of Examples 1 to 3, it can be seen that when the mass ratio of the first binder to the second binder is in the range of 1: (0.3~3), the corresponding all-solid-state batteries have relatively excellent cycle performance, discharge capacity and rate performance; in particular, when the mass ratio of the first binder to the second binder is 1:1, the corresponding all-solid-state batteries have even better cycle performance, discharge capacity and rate performance.

[0121] It can be seen from the test results of Comparative Examples 2 and 3 that when the temperature of the cross-linking treatment is constant, limiting the duration of the cross-linking treatment within an appropriate range is helpful to improve the cycle performance, discharge capacity and rate performance of the corresponding all-solid-state battery.

[0122] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

Claims

1. A binder composition, characterized in that comprising a first binder, a second binder, an initiator and an organic solvent; The first binder is a polymer containing an olefinic group, the second binder is a saturated polymer containing no olefinic group and no F, and the dipole moment of the organic solvent is ≤2.5 D.

2. The adhesive composition according to claim 1, wherein The first binder is at least one selected from styrene-butadiene rubber, nitrile rubber, polybutadiene rubber, natural rubber, chloroprene rubber, EPDM rubber, hydrogenated nitrile rubber, styrene-butadiene-styrene block copolymer and butyl rubber; or / and, the second binder is selected from at least one of polyisobutylene, EPDM rubber, silicone rubber, hydrogenated styrene-butadiene-styrene block copolymer, polymethyl methacrylate and polyethyl methacrylate; Or / and, the organic solvent is selected from at least one of ester solvents, xylene and alkane solvents.

3. The adhesive composition according to claim 1, characterized in that The number average molecular weights of the first binder and the second binder are M n1 and M n2 , where 10000≤M n1 ≤2000000,10000≤M n2 ≤2000000; Or / and, the weight average molecular weight of the first binder and the second binder are M w1 and M w2 , where 50000≤M w1 ≤10000000,50000≤M w2 ≤10000000; Optionally, the polymer dispersion indexes of the first binder and the second binder are PDI1 and PDI2, respectively, wherein PDI1=M w1 / M n1 And 1≤PDI1≤10, PDI2=M w2 / M n2 And 1≤PDI2≤10.

4. The adhesive composition according to claim 1, wherein The Mooney viscosities of the first binder and the second binder are ML1 and ML2, respectively, wherein 10 MU≤ML1(1+4)100℃≤200 MU or / and 10 MU≤ML1(1+8)125℃≤200 MU, 10≤ML2(1+4)100℃≤200 or / and 10≤ML2(1+8)125℃≤200.

5. The adhesive composition according to any one of claims 1 to 4, characterized in that In the binder composition, the sum of the mass of the first binder and the second binder is M1, the mass of the organic solvent is M2, and the ratio of M1 to M2 is (5-10):(90-95); Optionally, the mass of the initiator is M3, and the ratio of M1 to M3 is 100:(5~15).

6. The adhesive composition according to claim 5, characterized in that The mass ratio of the first binder to the second binder is 1:(0.3~3); Optionally, the mass ratio of the first binder to the second binder is 1:

1.

7. The adhesive composition according to any one of claims 1 to 4, characterized in that The binder composition further includes a lithium salt; Optionally, the mass of the lithium salt is M4, and the ratio of M1 to M4 is 10:(0.5~1).

8. An all-solid-state battery, characterized in that: The invention comprises a positive electrode sheet, a solid electrolyte membrane and a negative electrode sheet stacked in sequence, wherein at least one of the positive electrode sheet, the solid electrolyte membrane and the negative electrode sheet comprises a sulfide solid electrolyte and a binder, wherein the binder is formed by cross-linking the binder composition according to any one of claims 1 to 7 after removing the organic solvent; Optionally, the positive electrode active material in the positive electrode sheet is selected from nickel-cobalt-manganese ternary positive electrode material, and the negative electrode active material in the negative electrode sheet is selected from at least one of silicon, graphite, silicon-carbon and silicon-graphite composite.

9. A method for preparing an all-solid-state battery according to claim 8, characterized in that: The following steps are involved: A positive electrode sheet, a solid electrolyte membrane, and a negative electrode sheet are stacked in sequence to form an electrode assembly, wherein at least one of the positive electrode sheet, the solid electrolyte membrane, and the negative electrode sheet comprises a sulfide solid electrolyte and the binder composition after removing the organic solvent; The electrode assembly is subjected to isostatic pressing and cross-linking treatment to obtain the all-solid-state battery.

10. The method for preparing an all-solid-state battery according to claim 9, wherein: The positive electrode sheet, the solid electrolyte membrane and the negative electrode sheet all include a sulfide solid electrolyte and a binder composition after removing the organic solvent; the preparation method includes the following steps: Mixing the raw material of the positive electrode sheet and the binder composition to form a positive electrode slurry, coating the positive electrode slurry on a positive electrode current collector and drying the mixture to remove an organic solvent, thereby obtaining a positive electrode sheet; Mixing the raw material of the negative electrode sheet and the binder composition to form a negative electrode slurry, coating the negative electrode slurry on a negative electrode current collector and drying the negative electrode slurry to remove an organic solvent, thereby obtaining a negative electrode sheet; Mixing the raw material of the solid electrolyte membrane and the binder composition to form a solid electrolyte membrane slurry; coating the solid electrolyte membrane slurry on the surfaces of the positive electrode sheet and the negative electrode sheet respectively and drying the slurry to remove the organic solvent, thereby forming a first solid electrolyte membrane on the surface of the positive electrode sheet to obtain a composite positive electrode sheet; and forming a second solid electrolyte membrane on the surface of the negative electrode sheet to obtain a composite negative electrode sheet; stacking the composite positive electrode sheet and the composite negative electrode sheet so that the first solid electrolyte membrane contacts the second solid electrolyte membrane to obtain the electrode assembly; performing the isostatic pressing treatment and the cross-linking treatment on the electrode assembly to obtain the all-solid-state battery; Optionally, in the cross-linking step, the treatment temperature is 120-180° C. and the treatment time is 2-8 h.

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