Modified binder and preparation method thereof, electrolyte membrane, solid-state battery, battery pack and electric equipment

Abstract

The embodiment of the invention provides a modified binder and a preparation method thereof, an electrolyte membrane, a solid-state battery, a battery pack and electric equipment. The modified binder is one or more of nitrile rubber derivatives; the molecular side chain of the modified binder comprises carboxyl and amido. The modified binder provided by the invention has good electron conduction capability.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a modified binder and a preparation method thereof, an electrolyte membrane, a solid-state battery, a battery pack, and electrical equipment. Background Art

[0002] Solid-state batteries are considered an important development direction for next-generation secondary batteries due to their inherent safety and high energy density. Among them, solid-state batteries assembled with sulfide electrolytes are a key development direction.

[0003] At present, the binders used in the slurrying of sulfide electrolytes usually do not have the ability to conduct electrons, which limits the contact between sulfide electrolyte particles, resulting in the obstruction of ion conduction between particles, thereby reducing the overall ionic conductivity of the sulfide electrolyte membrane. Summary of the Invention

[0004] The present invention provides a modified binder and a preparation method thereof, an electrolyte membrane, a solid-state battery, a battery pack, and an electrical device. By modifying nitrile rubber or a derivative of nitrile rubber and connecting carboxyl and amino functional groups to the molecular side chains, the modified nitrile rubber or the derivative of nitrile rubber has good ion conductivity as a binder.

[0005] The first aspect of the present invention provides a modified binder, wherein the modified binder is one or more nitrile rubber derivatives;

[0006] The molecular side chains of the modified binder include carboxyl groups and amine groups.

[0007] According to one embodiment of the present invention, the modified binder includes a first group represented by formula (1) and a second group represented by formula (2),

[0008]

[0009] Wherein, R1 and R2 are each selected from one of propionic acid, methyl propionate, ethyl propionate, butyl propionate, propionitrile, phenethyl, 4-carboxyphenethyl, 4-ethylbenzenesulfonic acid, and ethyl glycerate.

[0010] According to one embodiment of the present invention, the ratio of the number of segments of the first group to the number of segments of the second group is 0.1-10.

[0011] According to one embodiment of the present invention, the ratio of the number of segments of the first group to the number of segments of the second group is 0.5-2.

[0012] According to one embodiment of the present invention, when the temperature is 25°C, the electronic conductivity of the modified binder is σe, 1×10 -10 S / cm≤σe≤1×10-9 S / cm;

[0013] And / or, the ionic conductivity of the modified binder is σ i , 1×10 -10 S / cm≤σ i ≤2×10 -7 S / cm.

[0014] A second aspect of the present invention provides a method for preparing the modified binder according to the first aspect, the method comprising the following steps:

[0015] The modified adhesive is obtained by subjecting the nitrile rubber masterbatch to acidification, hydrolysis and amination reactions.

[0016] According to one embodiment of the present invention, the modified binder is obtained by subjecting the nitrile rubber masterbatch to acid hydrolysis and amination reaction, comprising:

[0017] After the nitrile rubber masterbatch is dissolved, an acid solution is added to carry out a hydrolysis reaction at a first preset temperature for a first preset time to obtain a partially hydrolyzed nitrile rubber substance, and after the partially hydrolyzed nitrile rubber substance is dissolved, a reducing agent is added to carry out a reductive amination reaction at a second preset temperature for a second preset time to obtain the modified binder.

[0018] According to an embodiment of the present invention, the first preset temperature is 80-120° C., and the first preset time is 1-8 hours.

[0019] According to an embodiment of the present invention, the second preset temperature is 120-140° C., and the second preset time is 4-12 hours.

[0020] According to a third aspect of the present invention, an electrolyte membrane is provided, comprising an electrolyte and the modified binder as described in the first aspect, or the modified binder prepared by the preparation method as described in the second aspect.

[0021] According to an embodiment of the present invention, the electrolyte is a sulfide electrolyte.

[0022] According to an embodiment of the present invention, the mass of the modified binder is 0.05-0.1% of the mass of the electrolyte.

[0023] According to one embodiment of the present invention, when the temperature is 25°C, the electrolyte membrane ion conductivity σ is 0.5×10 -3 S / cm≤σ≤5×10 -3 S / cm.

[0024] A fourth aspect of the present invention provides a solid-state battery, comprising the modified binder as described in the first aspect, or the modified binder prepared by the preparation method as described in the second aspect, or the electrolyte membrane as described in the third aspect.

[0025] In a fifth aspect of the present invention, a battery pack is provided, comprising the modified binder as described in the first aspect, or the modified binder prepared by the preparation method as described in the second aspect, or the electrolyte membrane as described in the third aspect, or the solid-state battery as described in the fourth aspect.

[0026] The sixth aspect of the present invention provides an electrical device, which includes the modified binder described in the first aspect, or the modified binder prepared by the preparation method described in the second aspect, or the electrolyte membrane described in the third aspect, or the solid-state battery described in the fourth aspect, or the battery pack described in the fifth aspect.

[0027] The present invention provides a modified binder and preparation method thereof, an electrolyte membrane, a solid-state battery, a battery pack, and an electrical device. The modified binder is one or more nitrile rubber derivatives; the molecular side chains of the modified binder include carboxyl and amine functional groups. The modified molecular side chains include carboxyl and amine functional groups, which form intramolecular salts. The dipole-dipole interaction promotes the dissociation of the intramolecular salts, improving intramolecular and intermolecular ion conductivity, reducing the transport barrier between sulfide electrolyte particles, and thereby improving the overall ionic conductivity of the sulfide electrolyte membrane. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic structural diagram of the first group and the second group provided in this application. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below. The specific embodiments listed below are only for describing the principles and features of the present invention. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts are within the scope of protection of the present invention.

[0030] The first aspect of the present invention provides a modified binder, which is one or more nitrile rubber derivatives; the molecular side chains of the modified binder include carboxyl and amino functional groups.

[0031] Since rubber binders themselves lack the ability to conduct electrons, using them in the slurrying of sulfide electrolytes can avoid reactions with the sulfide electrolyte, but this can reduce the overall ionic conductivity of the sulfide electrolyte membrane. The present invention modifies the binder molecules themselves by introducing carboxyl and amine functional groups into the side chains with weak polarity, allowing the carboxyl and amine functional groups to form intramolecular salts. Since both the carboxyl anion and the quaternary ammonium cation are in the form of weak acid / weak base ions, they exert a certain electrostatic attraction on lithium ions, forming an intermolecular dipole effect, which allows lithium ions to dissociate from the adsorption equilibrium state in the binder, thus imparting ion conductivity.

[0032] Therefore, the present invention uses one or more of nitrile rubber (NBR) or its derivatives as a matrix, introduces amino groups and carboxyl groups on the molecular side chains, and utilizes the carboxyl and amino functional groups included in the modified molecular side chains to form intramolecular salts. The dissociation of the intramolecular salts is promoted through the dipole-dipole effect, thereby improving the intramolecular and intermolecular ion conductivity, reducing the transmission barrier between sulfide electrolyte particles, and thus improving the overall ionic conductivity of the sulfide electrolyte membrane.

[0033] The structures of the first group and the second group provided in this application are as follows: Figure 1 As shown, it includes a first group structure 11 or 12 and a second group structure 13 or 14.

[0034] In a specific embodiment, the modified binder includes a first group represented by formula (1) and a second group represented by formula (2),

[0035]

[0036] Wherein, R1 and R2 are each selected from one of propionic acid, methyl propionate, ethyl propionate, butyl propionate, propionitrile, phenethyl, 4-carboxyphenethyl, 4-ethylbenzenesulfonic acid, and ethyl glycerate.

[0037] It should be noted that R1 and R2 may be the same group or different groups.

[0038] Carboxyl and amine functional groups are introduced into the molecular side chains of NBR or NBR derivatives, so that the carboxyl and amine groups can form intramolecular salts, and the dissociation of the intramolecular salts is promoted by dipole-dipole action, thereby improving the ion conductivity of the molecule. When the ratio of carboxyl groups to amine groups is close, the proportion of formed inner salts increases accordingly, and the dissociation ability of lithium ions is also enhanced. When the ratio of the number of chain segments of the first group to the second group is 0.1 to 10, the ion conductivity of the binder is relatively excellent. Preferably, when the ratio of the number of chain segments of the first group to the second group is 0.5 to 2, the ion conductivity of the binder is even better.

[0039] In a specific embodiment, at a temperature of 25°C, the electronic conductivity σe of the modified binder is 1×10 - 10 S / cm≤σe≤1×10 -9 S / cm; and / or, ionic conductivity σ of the modified binder i , 1×10 -7 S / cm≤σ i ≤1×10 - 10 S / cm. For example, the electronic conductivity σe of the modified binder is 1×10 -10 S / cm, 2×10 -10 S / cm, 3×10 -10 S / cm, 4×10 -10 S / cm, 5×10 -10 S / cm, 6×10 -10 S / cm, 7×10 -10 S / cm, 8×10 -10 S / cm, 9×10 -10 S / cm, 1×10 -9 S / cm or the range of any two values ​​above. For example, the ionic conductivity σ of the modified binder is i 1×10 -10 S / cm, 5×10 -9 S / cm, 1×10 -9 S / cm, 5×10 -8 S / cm, 1×10 -8 S / cm, 1×10 -7 S / cm, 2×10 -7 S / cm or a range consisting of any two of the above values. When the electronic conductivity and / or ionic conductivity of the modified binder is within the above range, the electrolyte membrane has a stronger ion conductivity.

[0040] The second aspect of the present invention provides a method for preparing the modified binder according to the first aspect, the method comprising the following steps: subjecting a nitrile rubber masterbatch to acid hydrolysis and amination reaction to obtain the modified binder.

[0041] Specifically, nitrile rubber masterbatch, such as nitrile rubber, hydrogenated nitrile rubber, etc., is subjected to acid hydrolysis and amination reaction to obtain nitrile rubber derivatives whose molecular side chains include carboxyl groups and amine groups. The nitrile rubber derivatives whose molecular side chains include carboxyl groups and amine groups are modified adhesives.

[0042] The order of the acidification hydrolysis and amination reactions is not limited in this embodiment.

[0043] In a specific embodiment, the modified binder is obtained after acid hydrolysis and amination reaction of the nitrile rubber masterbatch, comprising: dissolving the nitrile rubber masterbatch, adding an acid solution, and performing a hydrolysis reaction at a first preset temperature for a first preset time to obtain a partially hydrolyzed nitrile rubber substance, and dissolving the partially hydrolyzed nitrile rubber substance, adding a reducing agent, and performing a reductive amination reaction at a second preset temperature for a second preset time to obtain the modified binder.

[0044] The first preset temperature is a controlled temperature for the hydrolysis reaction, such as 80° C., 100° C., 120° C., etc.; the first preset time is the reaction time of the hydrolysis reaction, such as 1 hour, 2 hours, 3 hours, etc.; the second preset temperature is a controlled temperature for the reductive amination reaction, such as 100° C., 150° C., 200° C., etc.; the second preset time is the reaction time of the reductive amination reaction, such as 4 hours, 10 hours, 16 hours, etc. This embodiment does not limit this.

[0045] Specifically, a nitrile rubber masterbatch is added to a solvent and stirred at 80°C until dissolved. An acid solution is then added in batches and reacted with the acid solution at a first preset temperature for a first preset time. After the reaction, the solvent is removed by distillation under reduced pressure and the mixture is rinsed thoroughly with distilled water until neutral. This yields a partially hydrolyzed nitrile rubber substance, in which a portion of the cyano groups in the molecule are replaced by carboxyl groups, thereby introducing carboxyl groups into the side chains. The partially hydrolyzed nitrile rubber substance is then added to a solvent and stirred at 80°C until dissolved. A reducing agent is then added in batches and reacted at a second preset temperature for a second preset time. After the reaction, the solvent is removed by distillation under reduced pressure and the mixture is rinsed thoroughly with distilled water until neutral. This yields a modified binder in which the remaining cyano groups in the molecule are replaced by amine groups, resulting in both carboxyl and amine groups in the molecular side chains. Carboxyl and amine groups are introduced into the molecular side chains through hydrolysis and reductive amination reactions, achieving molecular modification using simple reactions and imparting ion conductivity to the modified binder.

[0046] The solvent may be one or more of tetrahydrofuran, dioxane, N,N'-dimethylformamide, N,N'-dimethylacetamide, N-methylpyrrolidone, dichloromethane, dibromomethane, dibromoethane, chloroform, toluene, o-xylene, m-xylene, p-xylene, mesitylene, 1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, anisole, ethyl acetate, butyl acetate, butyl butyrate, isobutyl butyrate, methyl benzoate, and ethyl benzoate; the acid solution may be one or more of a concentration of 3 to 1 One or more of 2 mol / L hydrochloric acid, sulfuric acid, glacial acetic acid, and methanesulfonic acid solution; the reducing agent refers to a complex of a reducing agent and a catalyst, wherein the reducing agent can be one or more of hydrogen, hydrazine hydrate, hydrogen chloride, lithium aluminum hydride, sodium borohydride, borane, and diborane, and the catalyst can be one or more of elemental aluminum, iron, cobalt, nickel, copper, platinum, and palladium carbon. The amount of reducing agent added is 1% to 5% of the mass of the NBR masterbatch, and the mass ratio of the reducing agent to the catalyst is 1:1 to 100:1.

[0047] It should be noted that since the modified binder can be a single modified NBR or a single modified NBR derivative, or a mixture of modified NBR and a modified NBR derivative, the modified NBR and the modified NBR derivative can be prepared separately. When the mixture of modified NBR and the modified NBR derivative is used as the binder, they can be directly mixed.

[0048] In a preferred embodiment, the first preset temperature is 80-120°C, and the first preset time is 1-8 hours. Exemplarily, the first preset temperature is 80°C, 90°C, 100°C, 110°C, 120°C, or a range consisting of any two of the above values. Exemplarily, the first preset time is 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, or a range consisting of any two of the above values. By controlling the temperature and time of the hydrolysis reaction within the above ranges, some of the cyano groups in the molecule are hydrolyzed into carboxyl groups, thereby introducing carboxyl groups into the side chains of the molecule, avoiding complete hydrolysis of the cyano molecules due to overreaction, which makes it impossible to carry out the subsequent reductive amination reaction.

[0049] In a preferred embodiment, the second preset temperature is 120-140°C, and the second preset time is 4-12 hours. Exemplarily, the second preset temperature is 120°C, 125°C, 130°C, 135°C, 140°C, or a range consisting of any two of the above values. Exemplarily, the second preset time is 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, or a range consisting of any two of the above values. Controlling the reaction temperature and time can effectively achieve complete reductive amination of the remaining unhydrolyzed cyano groups in the polymer, preventing a small amount of unreacted HNBR or NBR structures from affecting the ionic conductivity of the final product.

[0050] The third aspect of the present invention provides an electrolyte membrane, comprising an electrolyte and a modified binder as in the first aspect, or a modified binder prepared by the preparation method of the second aspect. Due to the modification, the binder not only has ion conductivity but also is not easy to react with the electrolyte, thereby improving the overall ion conductivity of the electrolyte membrane. When preparing the electrolyte membrane, the prepared electrolyte slurry needs to be coated on the metal foil, dried and then rolled up. The surface energy difference between the rubber adhesives and metal foils commonly used at present is large, resulting in insufficient adhesion between the electrolyte slurry coated on the metal foil and the metal foil, and it is easy to fall off under the action of external force, affecting the rolling of the electrolyte membrane; and when the modified binder provided by the present invention is used to prepare the electrolyte slurry, the surface energy is significantly improved due to the introduction of carboxyl and amine groups into the molecular side chains. The electrolyte slurry has good bonding with the metal foil and can effectively prevent falling off.

[0051] In a preferred embodiment, the electrolyte is a sulfide electrolyte. Among them, the sulfide electrolyte can be Li6PS5Cl, Li2SGeS2, Li2SSiS2, (100-x)Li2S- x P2S5, Li2S-MS2-P2S5, Li2S-MS y -LiX, thio-LISICON, Li2S-SnS2-P2S5, Li2S-Al2S3-P2S5 or Li-Argyrodite, wherein the value range of x is 0≤x≤100, M is selected from any one of Si, Ge, Sn or P, X is selected from any one of halogen atoms, and the value range of y is 0≤y≤5, or a sulfide electrolyte system in which the above systems are doped and modified. When the electrolyte is a sulfide electrolyte, the ion conductivity of the obtained electrolyte membrane is stronger. Optionally, the modified binder provided by the present invention can also be used for electrolyte membranes prepared from oxide electrolytes or halide electrolytes.

[0052] In a preferred embodiment, the mass of the modified binder is 0.05-0.1% of the mass of the sulfide electrolyte. Exemplarily, the content of the binder is 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1% of the sulfide electrolyte or a range consisting of any two of the above values. Since the molecular weight of the commonly used rubber binders is relatively small and the degree of branching is relatively low, the viscosity is relatively weak, and the amount added when configuring the electrolyte slurry is relatively high. However, the molecular weight and degree of branching of the modified binder are significantly improved, and the viscosity increases accordingly. Therefore, the amount added when preparing the electrolyte membrane is reduced, saving costs. Moreover, controlling the content of the binder within the above range not only can provide good bonding with the metal foil, but also further improve the ionic conductivity of the electrolyte membrane, avoiding the decrease in the ionic conductivity of the electrolyte membrane due to excessive binder content.

[0053] In a specific embodiment, when the temperature is 25°C, the ionic conductivity of the electrolyte membrane is σ, 0.5×10 - 3 S / cm≤σ≤5×10 -3 S / cm. For example, the ionic conductivity σ of the electrolyte membrane is 0.5×10 -3 S / cm, 0.8×10 -3 S / cm, 1×10 -3 S / cm, 1.5×10 -3 S / cm, 2×10 -3 S / cm, 2.5×10 -3 S / cm, 3×10 -3 S / cm, 3.5×10 -3 S / cm, 4×10 -3 S / cm, 5×10 -3 S / cm or a range consisting of any two of the above values. A fourth aspect of the present invention provides a solid-state battery, comprising the modified binder of the first aspect, or the modified binder prepared by the preparation method of the second aspect, or the electrolyte membrane of the third aspect.

[0054] In a specific embodiment, the battery of the present invention can be prepared by the following method: a positive electrode sheet, a separator, and a negative electrode sheet are wound or stacked to form a bare cell, and the bare cell is encapsulated in a pre-stamped aluminum-plastic film bag. The encapsulated cell is then isostatically compacted (pressure ≥ 300 MPa), the tabs are welded, and the battery of the present invention is obtained by secondary packaging.

[0055] The modified binder of the present invention can also be used to prepare semi-solid batteries.

[0056] The fifth aspect of the present invention provides a battery pack, comprising a modified binder as in the first aspect, or a modified binder obtained by the preparation method as in the second aspect, or an electrolyte membrane as in the third aspect, or a solid-state battery as in the fourth aspect. The number of battery cells contained in the battery pack may be one or more, and the specific number can be selected by those skilled in the art based on the application and capacity of the battery pack. In some embodiments, the battery pack can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by those skilled in the art based on the application and capacity of the battery pack.

[0057] A sixth aspect of the present invention provides an electrical device comprising the modified binder of the first aspect, or the modified binder prepared by the preparation method of the second aspect, or the electrolyte membrane of the third aspect, or the solid-state battery of the fourth aspect, or the battery pack of the fifth aspect. The present invention does not particularly limit the type of electrical device; the device may be any electrical device that includes the battery, including but not limited to mobile phones, portable devices, laptop computers, electric bicycles, electric vehicles, electric toys, energy storage devices, and the like.

[0058] The modified binder and its preparation method, electrolyte membrane, solid-state battery, battery pack, and electrical equipment provided by the present invention will be specifically introduced below through specific examples.

[0059] Unless otherwise specified, the reagents, materials, and instruments used in the following examples are conventional reagents, conventional materials, and conventional instruments in the art and can be obtained commercially. The reagents involved can also be synthesized by conventional methods in the art.

[0060] Example 1

[0061] Preparation of modified binder

[0062] 1) 25 g of HNBR was placed in a 500 mL round-bottom flask, 250 mL of tetrahydrofuran was added, and the mixture was stirred at 80°C until dissolved. Subsequently, 5 g of 6 mol / L aqueous hydrochloric acid solution was added and reacted at 100°C for 2 hours. After the reaction, the solvent was removed by vacuum distillation and the mixture was thoroughly rinsed with distilled water until neutral to obtain partially hydrolyzed HNBR.

[0063] 2) 25 g of partially hydrolyzed HNBR was placed in a 500 mL round-bottom flask, 250 mL of toluene was added, and the mixture was stirred at 80° C. until dissolved. Subsequently, 0.25 g of Pd / H2 was added while hydrogen was continuously introduced. The mixture was reacted at 120° C. for 4 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and the mixture was thoroughly rinsed with distilled water until neutral, thereby obtaining a modified HNBR as a binder.

[0064] Preparation of electrolyte membrane

[0065] 3) 100 g of Li6PS5Cl, 80 g of xylene, and 0.1 g of the binder obtained in step 2) were mechanically stirred until thoroughly mixed, and then coated on a metal foil by transfer coating. The mixture was dried at 120°C and rolled up to obtain an electrolyte membrane.

[0066] Example 2

[0067] The difference between this embodiment and embodiment 1 is that the raw material in step 1) is replaced with NBR, and the other conditions are the same as those in embodiment 1.

[0068] Example 3

[0069] The difference between this embodiment and embodiment 1 is that the modified NBR and modified HNBR mixture of embodiments 1 and 2 is used as the modified binder, and the other conditions are the same as those of embodiments 1 and 2.

[0070] Example 4

[0071] The difference between this embodiment and embodiment 1 is that in step 1), hydrochloric acid is replaced by sulfuric acid, the reaction temperature is 80°C, and the reaction time is 1 h; in step 2), Pd / H2 is replaced by Fe / HCl, the reaction temperature is 120°C, and the reaction time is 12 h. The other conditions are the same as in embodiment 1.

[0072] Example 5

[0073] The difference between this embodiment and embodiment 1 is that in step 1), hydrochloric acid is replaced by sulfuric acid, the reaction temperature is 160° C., and the reaction time is 8 h; in step 2), Pd / H2 is replaced by Fe / HCl, the reaction temperature is 120° C., and the reaction time is 12 h. The other conditions are the same as in embodiment 1.

[0074] Example 6

[0075] The difference between this embodiment and embodiment 1 is that in step 1), hydrochloric acid is replaced with CF3SO3H, the reaction temperature is 50°C, and the reaction time is 0.5 h; in step 2), the reaction temperature is 120°C, and the reaction time is 12 h. The other conditions are the same as those in embodiment 1.

[0076] Example 7

[0077] The difference between this embodiment and embodiment 1 is that in step 1), hydrochloric acid is replaced with CF3SO3H, the reaction temperature is 180°C, and the reaction time is 10 h; in step 2), the reaction temperature is 120°C, and the reaction time is 12 h. The other conditions are the same as in embodiment 1.

[0078] Example 8

[0079] The difference between this embodiment and embodiment 1 is that Pd / H2 in step 2) is replaced by NaBH4, the reaction temperature is 100°C, the reaction time is 4 hours, and the other conditions are the same as those in embodiment 1.

[0080] Example 9

[0081] The difference between this embodiment and embodiment 1 is that Pd / H2 in step 2) is replaced with NaBH4, the reaction temperature is 250°C, the reaction time is 24h, and the other conditions are the same as those in embodiment 1.

[0082] Example 10

[0083] The difference between this embodiment and embodiment 1 is that hydrochloric acid in step 1) is replaced by CF3SO3H, Pd / H2 in step 2) is replaced by Fe / HCl, the reaction temperature is 60°C, the reaction time is 1 h, and the other conditions are the same as those in embodiment 1.

[0084] Example 11

[0085] The difference between this embodiment and embodiment 1 is that hydrochloric acid in step 1) is replaced by CF3SO3H, Pd / H2 in step 2) is replaced by Fe / HCl, the reaction temperature is 260°C, the reaction time is 26 h, and the other conditions are the same as those in embodiment 1.

[0086] Example 12

[0087] The difference between this embodiment and embodiment 1 is that the amount of binder in step 3) is 0.05 g, and the other conditions are the same as those in embodiment 1.

[0088] Example 13

[0089] The difference between this embodiment and embodiment 1 is that the amount of binder in step 3) is 0.075 g, and the other conditions are the same as those in embodiment 1.

[0090] Example 14

[0091] The difference between this embodiment and embodiment 1 is that the amount of binder in step 3) is 0.5 g, and the other conditions are the same as those in embodiment 1.

[0092] Comparative Example 1

[0093] The binder in this comparative example is unmodified HNBR, and the other conditions are the same as those in Example 12.

[0094] Comparative Example 2

[0095] The binder in this comparative example is a mixture of unmodified NBR and HNBR, and the other conditions are the same as those in Example 12.

[0096] Comparative Example 3

[0097] The difference between this comparative example and Example 12 is that in step 1), the reaction temperature is 100° C. and the reaction time is 24 h, HNBR containing carboxyl groups but no amine groups in the side chains is obtained and used as the binder, step 2) is deleted, and the remaining conditions are the same as in Example 12.

[0098] Comparative Example 4

[0099] The difference between this comparative example and Example 12 is that step 1) is deleted, the reaction temperature in step 2) is 120° C., the reaction time is 48 h, and HNBR containing amino groups but no carboxyl groups in the side chains is obtained, which is used as a binder. The other conditions are the same as those in Example 12.

[0100] Test Case

[0101] 1. The following performance tests were performed on the adhesives of the above embodiments and comparative examples:

[0102] 1. Infrared spectrum test

[0103] Test method: The adhesives prepared in Example 1 and Example 2 were subjected to infrared analysis using an infrared spectrometer. In FT-IR, the carbon group in -COOH was detected at ca. 1650-1780 cm -1 There are obvious characteristic peaks at the position, and the amino group is at 2600~3000cm -1 There is an obvious characteristic peak at the position of 1.47°. This characteristic peak does not exist in NBR and its derivatives, which can be used to identify that the carboxyl and amine functional groups are successfully connected to the side chains of the NBR molecules.

[0104] 2. Acid-base titration test

[0105] Test method: Determination of the carboxylic acid ratio (number of second group segments) after hydrolysis of NBR or HNBR: Dissolve 100 mg of hydrolyzed NBR or HNBR in 10 g of xylene. Measure the pH value with a pH meter while stirring. Titrate with 0.1 mol / L NaOH until a titration jump appears. Calculate the pH value according to the following formula:

[0106] Wherein, V1 is the volume of alkali solution used;

[0107] Determination of the proportion of amine groups after amination of NBR or HNBR (number of first group segments): Dissolve 100 mg of reductively aminated NBR or HNBR in 10 g of xylene. Measure the pH value with a pH meter while stirring. Titrate with 0.1 mol / L NaOH until a titration jump appears. Calculate the pH value according to the following formula:

[0108] Wherein, V1 is the volume of the alkali solution used, and V2 is the volume of the alkali solution used when determining the amino content.

[0109] 3. Ionic conductivity test

[0110] Test method: Dissolve an appropriate amount of binder in anisole to a concentration of 0.1 g / mL. Add LiTFSI in small batches to obtain a saturated solution. Drop the saturated solution onto a glass plate. After the solvent evaporates, a thin film is obtained. This film is assembled into a button cell with an SS|polymer|SS structure, where SS is a stainless steel sheet. The impedance is measured by EIS and the σ is calculated based on the σ. i = L / Rs to calculate ionic conductivity, where s is the contact area between the film and the stainless steel electrode, in cm 2, R is the impedance, unit is Ω -1 , L is the film thickness, in cm, the results are shown in Table 1.

[0111] 4. Electronic conductivity test

[0112] Test method: Dissolve an appropriate amount of binder in anisole to a concentration of 0.1 g / mL; add LiTFSI in small batches to obtain a saturated solution. The saturated solution is dropped onto a glass plate. After the solvent evaporates, a thin film is obtained. This film is assembled into a button cell using the SS|polymer|SS structure, where SS is stainless steel. The electronic conductivity is measured using the DC polarization method, calculated as σe=(I i -I s ) / (U i -U s ), where I is the current, U is the voltage, subscript i is the initial value, and s is the steady-state value. The results are shown in Table 1.

[0113] 2. The following performance tests were performed on the electrolyte membranes of the above embodiments and comparative examples:

[0114] 1. Ionic conductivity test

[0115] Test method: The electrolyte membrane is assembled into a button cell with an SS|polymer|SS structure, where SS is a stainless steel sheet. The impedance is measured by EIS and the ionic conductivity is calculated according to σ=L / Rs, where s is the contact area between the membrane and the stainless steel electrode, in cm 2 , R is the impedance, unit is Ω -1 , L is the film thickness, in cm, the results are shown in Table 1.

[0116] 2. Peel force test

[0117] Test method: Secure the aluminum foil side of the test electrode to the aluminum plate with double-sided tape. Attach the electrolyte side with 3M transparent tape, with a bonding area of ​​120mm x 40mm. Place the bonded aluminum plate in the clamp of the tensile testing machine, secure it, and clamp one end of the transparent tape with the other clamp. Stretch the tape tangentially at a rate of 1N / min. The stable value of the force recorded is the peel force.

[0118] Table 1

[0119]

[0120]

[0121]

[0122]

[0123] As shown in Table 1, it can be seen from the comparison of Examples 1 to 3 with Comparative Examples 1 to 4 that the unmodified HNBR or the mixture of HNBR and NBR itself does not have the ability to conduct ions and electrons. By using one or more of the modified NBR and modified HNBR as a binder, the binder itself has the ability to conduct ions, and the ionic conductivity of the electrolyte membrane obtained is significantly improved. However, the binder obtained by only performing acidic hydrolysis or reductive amination has limited improvement in the ability to conduct ions and electrons, and the ionic conductivity of the electrolyte membrane obtained is also low. From the comparison of Examples 4 to 11, it can be concluded that the interaction between the first group and the electrolyte membrane can be regulated by changing the conditions of the hydrolysis and amination reactions. When the ratio of the number of segments of the first group to the second group is within the range of 0.1 to 10, the ionic and electronic conductivity of the resulting binder, as well as the peeling strength and ionic conductivity of the resulting electrolyte membrane, are relatively high. Furthermore, when the ratio of the number of segments of the first group to the second group is within the range of 0.5 to 2, the ion conductivity of the resulting binder and electrolyte membrane is even better. Comparing Examples 12 to 14 with Example 1 shows that when preparing an electrolyte membrane, when the binder content is 0.05% to 0.1% of the sulfide electrolyte, the resulting electrolyte membrane can simultaneously exhibit good peeling strength and ionic conductivity. Example 3 shows that mixing the binder does not affect the ionic / electronic conductivity and peeling strength of the resulting electrolyte membrane.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A modified binder, characterized in that: The modified binder is one or more nitrile rubber derivatives; The molecular side chains of the modified binder include carboxyl groups and amine groups.

2. The modified binder according to claim 1, characterized in that The modified binder comprises a first group represented by formula (1) and a second group represented by formula (2), Wherein, R1 and R2 are each selected from one of propionic acid, methyl propionate, ethyl propionate, butyl propionate, propionitrile, phenethyl, 4-carboxyphenethyl, 4-ethylbenzenesulfonic acid, and ethyl glycerate.

3. The modified binder according to claim 2, characterized in that The ratio of the number of segments of the first group to the number of segments of the second group is 0.1 to 10.

4. The modified binder according to claim 3, characterized in that The ratio of the number of segments of the first group to the number of segments of the second group is 0.5-2.

5. The modified binder according to any one of claims 1 to 4, characterized in that: When the temperature is 25℃, the electronic conductivity of the modified binder is σe, 1×10 -10 S / cm≤σe≤1×10 -9 S / cm; And / or, the ionic conductivity of the modified binder is σ i , 1×10 -10 S / cm≤σ i ≤2×10 -7 S / cm.

6. A method for preparing the modified binder according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: The modified adhesive is obtained by subjecting the nitrile rubber masterbatch to acidification, hydrolysis and amination reactions.

7. The preparation method according to claim 6, characterized in that The modified binder is obtained by subjecting the nitrile rubber masterbatch to acidification, hydrolysis and amination reaction, comprising: After the nitrile rubber masterbatch is dissolved, an acid solution is added to carry out a hydrolysis reaction at a first preset temperature for a first preset time to obtain a partially hydrolyzed nitrile rubber substance, and after the partially hydrolyzed nitrile rubber substance is dissolved, a reducing agent is added to carry out a reductive amination reaction at a second preset temperature for a second preset time to obtain the modified binder.

8. The preparation method according to claim 7, characterized in that The first preset temperature is 80-120° C., and the first preset time is 1-8 hours.

9. The preparation method according to claim 7 or 8, characterized in that The second preset temperature is 120-140° C., and the second preset time is 4-12 hours.

10. An electrolyte membrane, characterized in that The electrolyte membrane comprises an electrolyte and the modified binder according to any one of claims 1 to 5, or the modified binder prepared by the preparation method according to claims 6 to 9.

11. The electrolyte membrane according to claim 10, characterized in that The electrolyte is a sulfide electrolyte.

12. The electrolyte membrane according to claim 10 or 11, characterized in that The mass of the modified binder is 0.05-0.1% of the mass of the electrolyte.

13. The electrolyte membrane according to any one of claims 10 to 12, characterized in that: When the temperature is 25°C, the ionic conductivity of the electrolyte membrane is σ, 0.5×10 -3 S / cm≤σ≤5×10 -3 S / cm.

14. A solid-state battery, characterized in that: The battery comprises the modified binder according to claims 1-5, or the modified binder prepared by the preparation method according to claims 6-9, or the electrolyte membrane according to any one of claims 10-13.

15. A battery pack, characterized in that: The battery pack includes the modified binder according to claims 1-5, or the modified binder prepared by the preparation method according to claims 6-9, or the electrolyte membrane according to claims 10-13, or the solid-state battery according to claim 14.

16. An electrical device, characterized in that: The electrical equipment includes the modified binder as described in claims 1-5, or the modified binder prepared by the preparation method as described in claims 6-9, or the electrolyte membrane as described in claims 10-13, or the solid-state battery as described in claim 14, or the battery pack as described in claim 15.

Images