Use of compounds in dispersing carbon materials and in negative electrode slurries

Abstract

This invention discloses the application of a compound in dispersed carbon materials and in negative electrode slurry, belonging to the field of battery material technology. The compound contains one or more structures as shown in Formula I. The compound provided by this invention has a good dispersing effect on carbon materials, and when applied to battery slurry, it can ensure that the material has good flowability, stability and processing performance.

Description

Technical Field

[0001] This invention belongs to the field of battery materials technology, specifically relating to the application of a compound in dispersed carbon materials and in negative electrode slurry. Background Technology

[0002] As a core material in lithium-ion batteries, the performance of the negative electrode slurry directly determines the battery's energy density and cycle life. Currently, commonly used negative electrode slurries mainly consist of graphite or silicon-based active materials, conductive agents, binders, and solvents. Among these, the dispersion state of the conductive agent has a decisive influence on the construction of the electrode's conductive network.

[0003] With the widespread application of silicon-based anode materials, their volume expansion characteristics of up to 300% place higher demands on the stability of the slurry, which makes the uniform dispersion of conductive agents a key technical bottleneck. At present, the industry generally adopts a mixed conductive system of carbon nanotubes (CNTs) and carbon black. However, CNTs are prone to agglomeration due to their huge aspect ratio and surface energy, and must rely on efficient dispersants to achieve nanoscale uniform distribution.

[0004] Conductive dispersants primarily improve interparticle interactions through physical adsorption or chemical bonding, and are mainly classified into three categories: polymeric, surfactant-based, and composite. Polymeric dispersants such as polyvinylpyrrolidone (PVP) stabilize particles through steric hindrance, while anionic surfactants such as sodium dodecylbenzenesulfonate (SDBS) rely on electrostatic repulsion.

[0005] CN115403016A provides a block copolymer dispersant that, through optimized molecular chain segment design, can simultaneously achieve CNT deagglomeration and stable suspension of graphene. However, existing dispersants still have significant drawbacks: metal residues in ionic dispersants can trigger electrolyte decomposition, increasing the battery cycle capacity decay rate by more than 15%; excessively high molecular weights in polymeric dispersants can lead to uncontrolled slurry viscosity, affecting the coating process; while bio-based dispersants are environmentally friendly, their efficiency is insufficient, making it difficult to meet the requirements of high-energy-density batteries.

[0006] Therefore, a new dispersant is needed to meet application requirements. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide an application of a compound in dispersed carbon materials and in negative electrode slurries.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides the use of a compound in dispersed carbon materials, said compound comprising one or more structures as shown in Formula I:

[0010] ;

[0011] in:

[0012] R1, R2, R3, R4, R5, R6, R7, and R8 are each independently selected from any one of the following: hydrogen atom, halogen atom, -OM, -COOM, -SO3M, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkoxy, substituted or unsubstituted cycloalkoxy, substituted or unsubstituted aryloxy, substituted or unsubstituted heteroaryloxy, substituted or unsubstituted cycloalkylalkyl, substituted or unsubstituted arylalkyl, substituted or unsubstituted heteroarylalkyl, substituted or unsubstituted cycloalkylalkoxy, substituted or unsubstituted arylalkoxy, substituted or unsubstituted heteroarylalkoxy, substituted or unsubstituted alkenyl, and substituted or unsubstituted alkynyl.

[0013] or,

[0014] Two adjacent atoms of R1, R2, R3, R4, R5, R6, R7, and R8 together with the carbon atoms bonded to them form a ring, which may or may not contain heteroatoms and / or may or may not contain substituents.

[0015] Furthermore, at least one of R1, R2, R3, R4, R5, R6, R7, and R8 is selected from -OM, -COOM, or -SO3M, where M is an alkali metal ion.

[0016] In this invention, by selecting a fused aromatic ring structure with a "large planar structure", the carbon material dispersant provided by this invention can be fixed on the surface of the carbon material by utilizing its π-π interaction, thus physically isolating the carbon material. At the same time, the introduced -OM, -COOM, -SO3M and other groups have good water solubility. Therefore, the combination of the fused aromatic ring structure and the water-soluble groups can not only physically isolate the carbon material, but also increase the dispersibility of the carbon material in water. That is, the carbon material dispersant provided by this invention can make the carbon material well dispersed in the solvent and avoid the carbon material from agglomerating.

[0017] Preferably, two adjacent groups of R1, R2, R3, R4, R5, R6, R7, and R8, together with the carbon atoms bonded to them, form 1-4 aromatic ring structures, wherein the aromatic ring structures may or may not contain heteroatoms, or may or may not contain substituents, and at least one group of R1, R2, R3, R4, R5, R6, R7, and R8, or at least one group with substituents including -OM, -COOM, and -SO3M, where M is an alkali metal ion.

[0018] Preferably, at least one group among R1, R2, R3, R4, R5, R6, R7, and R8 is selected from -OM, -COOM, and -SO3M, and at least one group among R1, R2, R3, R4, R5, R6, R7, and R8 is selected from substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted aralkyl (alkyl group attached to the main structure), and substituted or unsubstituted heteroaryl (alkyl group attached to the main structure); preferably, the substituted substituents include at least one of -OM, -COOM, or -SO3M, where at least one refers to at least one of -OM, -COOM, or -SO3M, or includes at least one -OM, at least one -COOM, or at least one -SO3M, where M is Li or Na.

[0019] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0020] Preferably, the molecular structure of the compound contains at least one of the structural units shown in Formula II, Formula III, and Formula IV:

[0021] ; ; ;

[0022] in:

[0023] A1 is absent, or A1 is selected from any of the substituted or unsubstituted C6-C30 arylene groups;

[0024] The substituents described in A1 are each independently selected from any one of -OM, -COOM, -SO3M, halogen, carboxyl, cyano, sulfonic acid, nitro, substituted or unsubstituted C1-C10 straight-chain or branched alkoxy, substituted or unsubstituted C5-C30 cycloalkyl, substituted or unsubstituted C1-C10 straight-chain or branched alkyl, and M is an alkali metal ion;

[0025] A2 is absent, or is selected from substituted or unsubstituted C1-C5 alkylene groups;

[0026] X1 and X2 are each independently selected from -CH= or -N=;

[0027] The linking site of the representative group;

[0028] The limitations for R1 to R8 are as described above.

[0029] In the carbon material dispersant provided by this invention, the -X1=X2- structure is further introduced, which can increase the interaction force between the dispersant and the carbon material, fix the dispersant on the surface of the carbon material, and thus isolate the carbon materials from each other, avoiding the agglomeration of the carbon materials. The introduction of the -X1=X2- structure makes the carbon material dispersant not only have a better dispersion effect on layered carbon materials, but also makes it suitable for the dispersion of carbon materials such as carbon nanotubes.

[0030] In one specific embodiment of the present invention, in Formula II, at least three of R1 to R8 are selected from -SO3M or -OM, A1 is selected from substituted phenyl groups, and the substituted group is nitro.

[0031] Preferably, A1 is selected from any one of the following groups, whether substituted or unsubstituted:

[0032] .

[0033] Preferably, the substituent includes at least one of -OM, -COOM or -SO3M, where M is Li or Na.

[0034] The A1 of the present invention may have more than one substituent. Therefore, the present invention defines the substituent as including at least one of -OM, -COOM or -SO3M, which means that all substituents in A1 include at least one of -OM, -COOM or -SO3M, or that all substituents in A1 include at least one -OM, at least one -COOM or at least one -SO3M.

[0035] Preferably, X1 is -CH= and X2 is -N=, or X1 is -N= and X2 is -CH=.

[0036] Preferably, the compound comprises one or more structures as shown in Formula V:

[0037] ;

[0038] in:

[0039] R9, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 R 18 Each is independently selected from H, -OM, -COOM, -SO3M, substituted or unsubstituted C1-C6, where M is an alkali metal ion;

[0040] And R9, R10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 R 18 It includes at least one of -OM, -COOM or -SO3M.

[0041] The R9 and R of the present invention 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 R 18 The inclusion of at least one of -OM, -COOM, or -SO3M refers to: in R9-R 18 At least one group in R9-R is selected from -OM, -COOM or -SO3M, and R9-R 18 It may include more than one -OM, -COOM, or -SO3M, and these multiple -OM, -COOM, or -SO3M may be the same or different. Examples are given below: for example, R9-R. 18 R in 11 R 13 R 16 R 18 Both are -SO3M, or R 11 R 13 For -SO3M, R 16 R 18 Examples of -OM, etc., will not be listed individually in this invention.

[0042] Preferably, the compound comprises one or more structures as shown in Formula II-1 or Formula II-2, or the molecular structure of the compound comprises structural units as shown in Formula II-3:

[0043] ;

[0044] in:

[0045] R1 to R8 are each independently selected from hydrogen atoms, -OM, -COOM or -SO3M, and at least one of R1 to R8 is selected from -SO3M, where M is an alkali metal ion;

[0046] R 1 ~R 5Each is independently selected from hydrogen atoms, -OM, -COOM, -SO3M, or phenyl groups, wherein the phenyl group has at least one substituent selected from -OM, -COOM, or -SO3M, and R 1 ~R 5 At least one of them includes -OM, -COOM, or -SO3M;

[0047] The linking site of the representative group.

[0048] Preferably, at least two of R1 to R8 are selected from -SO3M.

[0049] Preferably, M is Li + .

[0050] Preferably, in formula II-1, R 1 ~R 5 At most two of them are selected from -OM.

[0051] Preferably, in formula II-3, R 2 Selected from phenyl groups with substituents, wherein the substituents are selected from -SO3M.

[0052] In one specific embodiment of the present invention, in formula II-1, at least three of R1 to R8 are selected from -SO3M, R 1 ~R 5 At most two choices are selected from -OM, where M is Li. + .

[0053] In one specific embodiment of the present invention, in formula II-2, at least three of R1 to R8 are selected from -SO3M, where M is Li + .

[0054] In one specific embodiment of the present invention, in formula II-3, at least two of R1 to R8 are selected from -SO3M, R 2 The phenyl group is selected from a substituted group, wherein the substituent is selected from -SO3M, and M is Li. + .

[0055] Preferably, the compound comprises one or more structures as shown in Formula II-4 or Formula IV-1:

[0056] ;

[0057] in:

[0058] R1 to R8 are each independently selected from hydrogen atoms, -OM, -COOM or -SO3M, and at least one of R1 to R8 is selected from -SO3M, where M is an alkali metal ion;

[0059] R1 ~R 8 Each atom is independently selected from hydrogen, -OM, -COOM, -SO3M, or -NH-R a R a For substituted heteroaryl groups, the substituted group is a halogen, and R 1 ~R 8 At least one of them is selected from -SO3M;

[0060] A2 is selected from C1-C5 alkylene groups.

[0061] Preferably, R 1 Selected from -NH-R a R a It is dichlorotriazine.

[0062] In one specific embodiment of the present invention, in formula II-4, at least one of R1 to R8 is selected from -SO3M, R 1 ~R 8 At least one of them is selected from -SO3M and R 1 ~R 8 At least one of them is selected from -OM, where M is Li + .

[0063] In one specific embodiment of the present invention, in formula II-4, at least one of R1 to R8 is selected from -SO3M, R 1 ~R 8 At least one of them is selected from -SO3M,R 1 ~R 8 At least one of them is selected from -OM, where M is Li + And R 1 Selected from -NH-R a R a It is dichlorotriazine.

[0064] In one specific embodiment of the present invention, in Formula IV-1, A2 is selected from methylene.

[0065] Preferably, the molecular structure of the compound contains the structural unit shown in Formula VI:

[0066] ;

[0067] in:

[0068] R1~R8, R 1 ~R 4 R a ~R d Each atom is independently selected from hydrogen, -OM, -COOM, or -SO3M, and at least one of R1 to R8 is selected from -SO3M. 1 ~R4 At least one of them is selected from -SO3M,R a ~R d At least one of them is selected from -SO3M, where M is an alkali metal ion;

[0069] The linking site of the representative group.

[0070] Preferably, the compound comprises any one or a combination of at least two of the following compounds:

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077] ;

[0078] Where m4 is selected from integers ≥1, such as 1, 2, 3, 4, 5, 6, 9, 10, 12, 15, 20, etc., preferably integers between 2 and 4, such as 2, 3, 4, etc.

[0079] Preferably, the compound comprises any one or a combination of at least two of the following compounds:

[0080]

[0081]

[0082]

[0083]

[0084] ;

[0085] m4 is selected from 2, 3, or 4.

[0086] Preferably, in the application, the mass ratio of the compound to the carbon material is (0.1-10):1, for example, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.8:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, etc.

[0087] In a second aspect, the present invention provides the application of a compound in a negative electrode slurry, wherein the compound is any one of the compounds described in the first aspect.

[0088] Preferably, the application of the compound in the negative electrode slurry is the application of the compound as a dispersant for the conductive agent in the negative electrode slurry.

[0089] Preferably, in the negative electrode slurry, the content of the compound is 0.005-1 wt% of the solid mass of the negative electrode slurry, for example, 0.05 wt%, 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.08 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, etc.

[0090] The solid content in the negative electrode slurry refers to the mass of all other substances excluding the solvent. For example, when the negative electrode slurry includes negative electrode active material, conductive agent, binder, and solvent, the solid content of the negative electrode slurry refers to the total mass of negative electrode active material, conductive agent, and binder excluding the solvent.

[0091] Thirdly, the present invention provides a carbon material dispersion containing carbon material and the compound described in the first aspect.

[0092] Preferably, the mass ratio of the compound to the carbon material is (0.1-10):1, for example, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.8:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, etc.

[0093] Preferably, the solid content of the carbon material dispersion is 1-10%, such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc.

[0094] Preferably, the carbon material is selected from at least one of graphene, conductive graphite, carbon black, Ketjen black, conductive carbon black, carbon fiber, and carbon nanotubes, preferably conductive graphite or carbon nanotubes, more preferably carbon nanotubes, and even more preferably single-walled carbon nanotubes.

[0095] Fourthly, the present invention provides a method for preparing a carbon material dispersion as described in the third aspect, the method comprising:

[0096] The carbon material and the compound are mixed in a dispersion solvent to obtain the carbon material dispersion.

[0097] Preferably, the mixing method includes at least one of homogenous mixing, ball milling, or planetary mixing.

[0098] Fifthly, the present invention provides an application of the carbon material dispersion as described in the fourth aspect in a lithium-ion battery, preferably in a negative electrode slurry, and more preferably as a conductive agent in a negative electrode slurry.

[0099] In a sixth aspect, the present invention provides a negative electrode slurry containing the compound described in the first aspect or the carbon material dispersion described in the third aspect.

[0100] Preferably, in the negative electrode slurry, the content of the compound is 0.005-1 wt% of the solid content of the negative electrode slurry, for example, 0.05 wt%, 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.08 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, etc.

[0101] In a seventh aspect, the present invention provides a method for preparing a negative electrode slurry as described in the sixth aspect, the method comprising:

[0102] The compound is mixed with the remaining components of the negative electrode slurry to obtain the negative electrode slurry;

[0103] Alternatively, the preparation method includes:

[0104] The carbon material dispersion is mixed with the remaining components of the negative electrode slurry, excluding the conductive agent, to obtain the negative electrode slurry.

[0105] Preferably, the mixing method includes at least one of homogenous mixing, ball milling, or planetary mixing.

[0106] Preferably, the amount of the compound added is 0.005-1 wt% of the solid content in the negative electrode slurry, for example, 0.05 wt%, 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.08 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, etc.

[0107] Preferably, the amount of carbon material dispersion added is such that the mass of the compound is 0.005-1 wt% of the solid content in the negative electrode slurry, for example, 0.05 wt%, 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.08 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, etc.

[0108] Compared with the prior art, the present invention has the following beneficial effects:

[0109] (1) The compounds provided by this invention have good dispersing effects on carbon materials, especially carbon nanotubes;

[0110] (2) When the compound provided by the present invention is applied to the negative electrode slurry, it can ensure that the negative electrode slurry has good fluidity, stability and processing performance. Attached Figure Description

[0111] Figure 1 For the preparation of compound A1 provided in Example 1 1 H-NMR test pattern;

[0112] Figure 2 For the preparation of compound A3 provided in Example 2 1 H-NMR test image. Detailed Implementation

[0113] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0114] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used in this invention, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may also include other elements not expressly listed or elements inherent to such a composition, step, method, article, or apparatus.

[0115] "Optionally", "maybe", "any one" means that the matter or event described thereafter may or may not occur, and the description includes both the possibility that the event may occur and the possibility that the event may not occur.

[0116] The indefinite articles “a” and “an” preceding an element or component of this invention do not impose any limitation on the quantity (i.e., number of occurrences) of the element or component. Therefore, “an” or “a” should be interpreted as including one or at least one, and the singular form of an element or component also includes the plural form, unless the quantity clearly refers only to the singular form.

[0117] The terms "one embodiment," "some embodiments," "exemplary," "specific example," or "some examples," etc., used in this invention refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this document, the illustrative expressions of the above terms are not necessarily directed at the same embodiment or example.

[0118] Furthermore, the technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0119] The following will use several examples to illustrate the application of the compound in dispersed carbon materials and the application of the compound in negative electrode slurry, as well as the specific components and preparation methods of carbon material dispersion and negative electrode slurry. However, the components and preparation methods of negative electrode sheets and lithium-ion batteries described in this invention are not limited to these examples.

[0120] In the following specific embodiments, the structure of the dispersant is as follows:

[0121]

[0122]

[0123]

[0124]

[0125] .

[0126] Unless otherwise specified, the raw materials involved in the following specific embodiments of the present invention are all conventional materials in the art and can be purchased from commercially available products.

[0127] The following are the synthetic methods for the above-mentioned compounds.

[0128] Preparation Example 1

[0129] This preparation example provides a compound A1, which is prepared by the following method:

[0130]

[0131] Weigh 1.368 g of terephthalaldehyde and 7.816 g of 2-naphthylamine-3,6,8-trisulfonic acid, add them to 100 g of water, mix well, and then add 2.52 g of lithium hydroxide monohydrate. Stir and heat to 50 °C and react for 4.5 h to obtain a transparent solution, which is an aqueous solution of compound A1. Remove the solvent by rotary evaporation and dry under vacuum to obtain product A1 with a yield of 98.3%.

[0132] By nuclear magnetic resonance hydrogen spectrum ( 1 The product A1 was characterized by ¹H-NMR (400 MHz, D₂O solvent) to obtain... 1 H-NMR test results are as follows Figure 1 As shown, this confirms that it has the target structure.

[0133] Preparation Example 2

[0134] This preparation example provides a compound A3, which is prepared by the following method:

[0135]

[0136] Weigh 1.38 g of 3,4-dihydroxybenzaldehyde and 3.83 g of 2-naphthylamine-3,6,8-trisulfonic acid, add them to 100 g of water, mix well, and then add 2.1 g of lithium hydroxide monohydrate. Stir and heat to 50 °C for 4 h to obtain a brown solution, which is an aqueous solution of compound A3. Remove the solvent by rotary evaporation and dry under vacuum to obtain product A3 with a yield of 98.1%.

[0137] By nuclear magnetic resonance hydrogen spectrum ( 1 The product A3 was characterized by ¹H-NMR (400 MHz, D₂O solvent) to obtain... 1 H-NMR test results are as follows Figure 2 As shown, this confirms that it has the target structure.

[0138] Preparation Example 3-12

[0139] This preparation example provides a carbon material dispersion and its preparation method, as follows:

[0140] Single-walled carbon nanotubes were mixed with compounds A1-A5 and B1-B5 as carbon material dispersants at a ratio of 0.4:0.6. The mixture was stirred and dispersed in deionized water for 30 min to obtain 1 kg of mixed solution with a solid content of 1%. The solution was homogenized at 200 bar for 5 min, and then the pressure was adjusted to 400 bar for 25 min. The dispersion of single-walled carbon nanotubes was observed under a microscope, and the results were judged. The final solid content of the dispersion was 1 ± 0.2%.

[0141] Preparation Examples 13-22

[0142] This preparation example provides a carbon material dispersion and its preparation method.

[0143] Graphene and carbon nanotubes were combined in a mass ratio of 4:0.5, or graphene was mixed with compounds A1-A5 and B1-B5 as carbon material dispersants in a mass ratio of 4.5:0.5 (carbon material:dispersant mass ratio). The mixture was stirred and dispersed in deionized water for 30 min to obtain 1 kg of mixed solution with a solid content of 5%. The solution was homogenized in a homogenizer at 100 bar for 20 min, and then the pressure was adjusted to 500 bar for 25 min. The dispersion was observed under a microscope, the results were judged, and the final solid content of the dispersion was 1 ± 0.2%.

[0144] Preparation Examples 23-32

[0145] This preparation example provides a carbon material dispersion and its preparation method.

[0146] Compounds A1-A5 and B1-B5 were used as carbon material dispersants and dispersed with deionized water. Conductive carbon black SP was added in batches at a mass ratio of 2:1 between the amount of conductive carbon black SP and the dispersant. The mixture was dispersed at 1800 rpm for 120 min to obtain 1 kg of mixed solution with a solid content of 3%. The dispersion of carbon nanotubes was observed under a microscope, and the results were judged. The final solid content of the dispersion was 3% ± 0.2%.

[0147] Preparation Examples 33-34

[0148] This preparation example provides a carbon material dispersion and its preparation method.

[0149] The difference from Preparation Example 23 is that in this preparation example, the amount of carbon material dispersant added is changed so that its content in the carbon material dispersion is 0.1 wt% (Preparation Example 33) and 2 wt% (Preparation Example 34).

[0150] Preparation Examples 35-36

[0151] This preparation example provides a carbon material dispersion and its preparation method.

[0152] The difference from Preparation Example 23 is that in this preparation example, the amount of deionized water added was changed so that the solid content of the carbon material dispersion was 1% (Preparation Example 35) and 10% (Preparation Example 36).

[0153] Preparation Examples 37-46

[0154] This preparation example provides a carbon material dispersion and its preparation method.

[0155] Graphite and carbon material dispersants (compounds A1-A2 and compound B1) were mixed in a ratio of 0.4:0.6 and dispersed in deionized water for 30 min to obtain 1 kg of mixed solution with a solid content of 1%. The solution was homogenized in a homogenizer at 200 bar for 5 min, and then the pressure was adjusted to 400 bar for 25 min. The dispersion was observed under a microscope, the results were judged, and the final solid content of the dispersion was 1 ± 0.2%.

[0156] Comparative Preparation Example 1

[0157] This comparative example provides a carbon material dispersion.

[0158] The difference from Preparation Example 3 is that no carbon material dispersant was added in this comparative preparation example.

[0159] Comparative Preparation Example 2

[0160] This comparative example provides a carbon material dispersion.

[0161] The difference from Preparation Example 3 is that in this comparative preparation example, the carbon material dispersant is CMC.

[0162] Comparative preparation example 3

[0163] This comparative example provides a carbon material dispersion.

[0164] The difference from Preparation Example 23 is that no carbon material dispersant was added in this comparative preparation example.

[0165] Performance Test 1: Dispersion Test of Carbon Material Dispersion Liquid

[0166] (1) The viscosity of the final carbon material dispersion was tested using the following method:

[0167] Fill a 250 mL glass beaker with the sample to be tested, ensuring no air bubbles are introduced. Place the beaker containing the sample in a constant temperature bath for at least 1 hour until the temperature reaches 25±0.2℃ before starting the test. Select a suitable rotor and speed (preferably select the 4# 60 rpm 10000 range based on the viscosity being tested) so that the reading falls within 20%-90% of the range. Keep the rotor and sample at the same constant temperature. Before use, wipe the rotor dry with lint-free paper. Start the motor and operate the instrument according to the instruction manual. Record the viscosity value for 1 minute. Stop the motor and wait for the rotor to stop before restarting the motor for testing. Perform the test once every 1 minute, and repeat the test 3 times. Report the result with the lowest measured value. After the test is completed, remove the rotor and clean it with a suitable solvent.

[0168] (2) Store at 40℃ for 3 days, then pour out the liquid to observe its flow and state.

[0169] The test results are shown in Table 1:

[0170] Table 1

[0171]

[0172] As shown in Table 1, the carbon material dispersant provided by this invention can effectively disperse carbon materials, especially layered carbon materials such as graphene, and also has a good dispersing effect on carbon nanotubes. Furthermore, it can ensure the long-term stable dispersion of carbon materials.

[0173] In the following embodiments, the waterborne binder, specifically the waterborne polyacrylic acid binder (PAA binder), was prepared according to the method of Example 1 in prior art CN111139002A; the styrene-butadiene rubber (SBR) was Yanyi BONE-Z8; the carboxymethyl cellulose binder (CMC) was a commercially available product; and the conductive carbon black Super P was a commercially available product. Other materials used in the preparation of the negative and positive electrode sheets were all commercially available chemicals.

[0174] Examples 1-10

[0175] This embodiment provides a negative electrode slurry and its preparation method.

[0176] (1) Weigh graphite, conductive carbon black SP, binder CMC and styrene-butadiene rubber SBR in a mass ratio of 96.7:0.6:1.3:1.4;

[0177] (2) Add graphite, CMC and SP dry powder into a double planetary homogenizer for dry mixing. Slow and fast mixing are carried out simultaneously to ensure thorough mixing.

[0178] (3) Add deionized water to the double planetary homogenizer and knead it with the mixture obtained in the above steps. The solid content is about 65-68%. Disperse for 5 minutes, with a revolution of 35° and a rotation of 0°. Scrape the material. Continue to disperse for 90 minutes, with a revolution of 45° and a rotation of 0°. (When the kneading is too thin, turn on the rotation at 400 rpm.) Scrape the material during the process.

[0179] (4) Adjust the solid content to between 50-60% with deionized water, disperse for 60-90 min, revolve at 45 degrees and rotate at 3500 degrees to ensure that each component is evenly dispersed in the entire slurry system;

[0180] (5) Add SBR to the mixed slurry and stir slowly for 30 min. Then add 0.20 wt% of compounds A1-A5 and B1-B5 as carbon material dispersants and continue stirring slowly.

[0181] (6) Viscosity adjustment and vacuum defoaming.

[0182] Examples 11-20

[0183] This embodiment provides a negative electrode slurry and its preparation method.

[0184] SIC / C (C ONE-SC 1800 (Zhejiang Lichen New Material Technology Co., Ltd.): SP: CMC: Conductive Dispersion (Preparation Example 3-12): Binder is mixed at a mass ratio of 96.5:0.5:0.3:0.12:2.58 (based on solids), wherein:

[0185] A. The negative electrode material (SiC / C), CMC dry powder and SP conductive agent are added to a double planetary homogenizer for dry mixing. Slow stirring and fast stirring are carried out simultaneously to ensure that the two are fully mixed.

[0186] B. Add the carbon material dispersion provided in Preparation Example 3-12 as a conductive dispersion, and deionized water to a double planetary homogenizer to knead the mixture. The solid content is about 60-65%. Disperse for 5 minutes, with a revolution of 35° and a rotation of 0°, and scrape the material. Continue dispersing for 90 minutes, with a revolution of 45° and a rotation of 0° (when the kneading is too thin, turn on the rotation at 400 rpm). Scrape the material during the process.

[0187] C. Add the binder to the double planetary homogenizer and stir it with the mixed slurry. Adjust the solid content to between 40-50% with deionized water. Disperse for 60-90 minutes, with a revolution of 45 degrees and a rotation of 3500 degrees, so that the binder is evenly dispersed in the entire slurry system and the conductive material is evenly distributed.

[0188] D. Adjust viscosity and vacuum defoaming to form a uniform negative electrode slurry.

[0189] Examples 21-30

[0190] This embodiment provides a negative electrode slurry and its preparation method.

[0191] The difference from Example 11 is that, in this example, the conductive dispersion is the carbon material dispersion provided in Preparation Examples 13-22.

[0192] Examples 31-44

[0193] This embodiment provides a negative electrode slurry and its preparation method.

[0194] Graphite:SP (dispersion provided in Preparation Examples 23-36):CMC:SBR were mixed at a mass ratio of 96.7:1.2:1:1.1 (based on solids), wherein:

[0195] A. Graphite and CMC dry powder are added to a double planetary homogenizer for dry mixing, with slow and fast mixing performed simultaneously to ensure thorough mixing.

[0196] B. Add the carbon material dispersion provided in Preparation Examples 23-36 as a conductive dispersion, and deionized water to a dual planetary homogenizer to knead the mixture. The solid content is about 65-68%. Disperse for 5 minutes, with a revolution of 35° and a rotation of 0°, and scrape the material. Continue dispersing for 90 minutes, with a revolution of 45° and a rotation of 0° (when the kneading is too thin, turn on the rotation at 400 rpm). Scrape the material during the process.

[0197] C. Adjust the solid content to between 50-60% with deionized water, disperse for 60-90 min, rotate 45 degrees around the sun and 3500 degrees on its own axis to ensure that each component is evenly dispersed in the entire slurry system, and also to ensure that SP is evenly distributed.

[0198] D. Add SBR to a dual planetary homogenizer and mix slowly with the slurry for 30 minutes.

[0199] E. Adjust viscosity and perform vacuum defoaming to form a uniform negative electrode slurry.

[0200] Examples 45-46

[0201] This embodiment provides a negative electrode slurry and its preparation method.

[0202] The difference from Example 1 is that in this example, the amount of compound A1 added is changed so that the amount of compound A1 added accounts for 0.05 wt% of the mass of the mixture (Example 45) and 1 wt% (Example 46).

[0203] Comparative Example 1

[0204] This comparative example provides a negative electrode slurry.

[0205] The difference from Example 1 is that no carbon material dispersant is added in this comparative example.

[0206] Comparative Examples 2-4

[0207] This comparative example provides a negative electrode slurry.

[0208] The difference from Example 11 is that, in this comparative example, the conductive paste is the carbon material dispersion provided in Comparative Preparation Examples 1-3.

[0209] Performance Test 2

[0210] The negative electrode slurries provided in Examples 1-46 and Comparative Examples 1-4 were used to prepare negative electrode sheets. The method was as follows: the slurry was coated onto the copper foil of the negative electrode current collector, dried, and cold-pressed to obtain the negative electrode sheet; and the performance of the obtained negative electrode sheet was tested, using the following method:

[0211] (1) Cut the negative electrode sheet to be tested into a rectangle of 30 mm × 100 mm, and use a tensile testing machine to test the adhesion force. The tensile speed is 100 mm / min, the width is 30 mm, and the weight is 1 gf.

[0212] (2) Cut the electrode to be tested into a circular piece with a diameter of 12 mm, measure the thickness with a micrometer, and take 6 circular pieces with similar thicknesses to perform resistance tests using a resistance testing instrument and take the average value.

[0213] The test results are shown in Table 2:

[0214] Table 2

[0215]

[0216] As can be seen from the examples and performance tests, when carbon material dispersant or conductive paste containing carbon material dispersant is added to the negative electrode paste, the negative electrode paste can have better fluidity and stability. At the same time, the conductive agent in the final negative electrode sheet is uniformly dispersed, the peel strength is high, and the film resistance is low.

[0217] In the following application examples, the other materials used to prepare the negative electrode and the positive electrode are all commercially available chemicals.

[0218] Application Example 1-46

[0219] This application example provides a lithium-ion battery and its preparation method.

[0220] (1) Preparation of negative electrode sheet: Referring to the performance test (2), the negative electrode slurry provided in Examples 1-46 was used to prepare the negative electrode sheet;

[0221] (2) Preparation of positive electrode sheet: The positive active material (nickel cobalt manganese ternary material, NCM811), conductive carbon black SP, carbon nanotubes CNT and binder (polyvinylidene fluoride, PVDF) are mixed in a mass ratio of 96.2:1.5:1:1.3 to obtain a positive electrode material composition; the positive electrode material composition is mixed with N-methylpyrrolidone NMP and stirred and dispersed evenly to obtain a positive electrode slurry with a solid content of 72%; the positive electrode slurry is uniformly coated on an aluminum foil current collector, dried and cold pressed to obtain a positive electrode sheet.

[0222] (3) Battery assembly: Using the negative electrode sheet provided in step (1) and the positive electrode sheet provided in step (2), and using a PE separator (Shenzhen Xingyuan Material Technology Co., Ltd.), an electrolyte (1 mol / L LiPF6 electrolyte, with the solvent being ethylene carbonate EC: diethyl carbonate DEC: methyl ethyl carbonate EMC: propylene carbonate PC=3:4:2:1) is injected to assemble a lithium-ion battery with model number 425065P.

[0223] Compare and contrast examples 1-4

[0224] This comparative application example provides a lithium-ion battery and its preparation method.

[0225] The difference from Application Example 1 is that, in this comparative application example, the negative electrode slurry is replaced with the negative electrode slurry provided in Comparative Examples 1-4.

[0226] The present invention has been illustrated through the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. The application of a compound in dispersed carbon materials, characterized in that, The compound comprises one or more structures as shown in Formula I: ； in: R1, R2, R3, R4, R5, R6, R7, and R8 are each independently selected from any one of the following: hydrogen atom, halogen atom, -OM, -COOM, -SO3M, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkoxy, substituted or unsubstituted cycloalkoxy, substituted or unsubstituted aryloxy, substituted or unsubstituted heteroaryloxy, substituted or unsubstituted cycloalkylalkyl, substituted or unsubstituted arylalkyl, substituted or unsubstituted heteroarylalkyl, substituted or unsubstituted cycloalkylalkoxy, substituted or unsubstituted arylalkoxy, substituted or unsubstituted heteroarylalkoxy, substituted or unsubstituted alkenyl, and substituted or unsubstituted alkynyl. or, Two adjacent atoms of R1, R2, R3, R4, R5, R6, R7, and R8 together with the carbon atoms bonded to them form a ring, which may or may not contain heteroatoms and / or may or may not contain substituents. Furthermore, at least one of R1, R2, R3, R4, R5, R6, R7, and R8 is selected from -OM, -COOM, or -SO3M, where M is an alkali metal ion.

2. The application according to claim 1, characterized in that, The molecular structure of the compound contains at least one of the structural units shown in Formula II, Formula III, and Formula IV: ； ； ； in: A1 is absent, or A1 is selected from any of the substituted or unsubstituted C6-C30 arylene groups; The substituents described in A1 are each independently selected from any one of -OM, -COOM, -SO3M, halogen, carboxyl, cyano, sulfonic acid, nitro, substituted or unsubstituted C1-C10 straight-chain or branched alkoxy, substituted or unsubstituted C5-C30 cycloalkyl, substituted or unsubstituted C1-C10 straight-chain or branched alkyl, and M is an alkali metal ion; A2 is absent, or is selected from substituted or unsubstituted C1-C5 alkylene groups; X1 and X2 are each independently selected from -CH= or -N=; The linking site of the representative group; The limitations of R1 to R8 are defined in claim 1; Preferably, A1 is selected from any one of the following groups, whether substituted or unsubstituted: ； Preferably, the substituent includes at least one of -OM, -COOM or -SO3M, where M is Li or Na; Preferably, X1 is -CH= and X2 is -N=, or X1 is -N= and X2 is -CH=.

3. The application according to claim 1 or 2, characterized in that, The compound comprises one or more structures as shown in Formula V: ； in: R9, R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 each independently selected from H, -OM, -COOM, -SO3M, substituted or unsubstituted C1-C6, M is an alkali metal ion; And R9, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 R 18 It includes at least one of -OM, -COOM or -SO3M.

4. The application according to any one of claims 1-3, characterized in that, The compound comprises one or more structures as shown in Formula II-1 or Formula II-2, or the molecular structure of the compound comprises structural units as shown in Formula II-3: ； in: R1 to R8 are each independently selected from hydrogen atoms, -OM, -COOM or -SO3M, and at least one of R1 to R8 is selected from -SO3M, where M is an alkali metal ion; R 1 ~R 5 Each is independently selected from hydrogen atoms, -OM, -COOM, -SO3M, or phenyl groups, wherein the phenyl group has at least one substituent selected from -OM, -COOM, or -SO3M, and R 1 ~R 5 At least one of them includes -OM, -COOM, or -SO3M; The linking site of the representative group; Preferably, at least two of R1 to R8 are selected from -SO3M; Preferably, M is Li + .

5. The application according to claim 4, characterized in that, In Equation II-1, R 1 ~R 5 At most two of them are selected from -OM; And / or, in Equation II-3, R 2 Selected from phenyl groups with substituents, wherein the substituents are selected from -SO3M.

6. The application according to any one of claims 1-3, characterized in that, The compound comprises one or more structures as shown in Formula II-4 or Formula IV-1: ； in: R1 to R8 are each independently selected from hydrogen atoms, -OM, -COOM or -SO3M, and at least one of R1 to R8 is selected from -SO3M, where M is an alkali metal ion; R 1 ~R 8 Each atom is independently selected from hydrogen, -OM, -COOM, -SO3M, or -NH-R a R a For substituted heteroaryl groups, the substituted group is a halogen, and R 1 ~R 8 At least one of them is selected from -SO3M; A2 is selected from C1-C5 alkylene groups; Preferably, R 1 Selected from -NH-R a R a It is dichlorotriazine.

7. The application according to any one of claims 1-6, characterized in that, The molecular structure of the compound described contains the structural unit shown in Formula VI: ； in: R1~R8, R 1 ~R 4 R a ~R d Each atom is independently selected from hydrogen, -OM, -COOM, or -SO3M, and at least one of R1 to R8 is selected from -SO3M. 1 ~R 4 At least one of them is selected from -SO3M,R a ~R d At least one of them is selected from -SO3M, where M is an alkali metal ion; The linking site of the representative group.

8. The application according to any one of claims 1-7, characterized in that, The compound includes any one or a combination of at least two of the following compounds: ； Where m4 is selected from integers ≥1, preferably integers between 2 and 4; Preferably, the compound comprises any one or a combination of at least two of the following compounds: ； m4 is selected from 2, 3, or 4; Preferably, in the application, the mass ratio of the compound to the carbon material is (0.1-10):

1.

9. The application of the compound in negative electrode slurry, characterized in that, The compound is the compound according to any one of claims 1-8; Preferably, the application of the compound in the negative electrode slurry is the application of the compound as a dispersant for the conductive agent in the negative electrode slurry; Preferably, in the negative electrode slurry, the content of the compound is 0.005-1 wt% of the solid mass of the negative electrode slurry.

10. A carbon material dispersion, characterized in that, The carbon material dispersion contains carbon material and the compound according to any one of claims 1-8; Preferably, the mass ratio of the compound to the carbon material is (0.1-10):1; Preferably, the solid content of the carbon material dispersion is 1-10%; Preferably, the carbon material is selected from at least one of graphene, conductive graphite, carbon black, Ketjen black, conductive carbon black, carbon fiber, and carbon nanotubes, preferably conductive graphite or carbon nanotubes, and more preferably carbon nanotubes.

11. A method for preparing a carbon material dispersion as described in claim 10, characterized in that, The preparation method includes: The carbon material and the compound are mixed in a dispersion solvent to obtain the carbon material dispersion. Preferably, the mixing method includes at least one of homogenous mixing, ball milling, or planetary mixing.

12. An application of the carbon material dispersion as described in claim 10 in a lithium-ion battery, preferably in a negative electrode slurry, and more preferably as a conductive agent in a negative electrode slurry.

13. A negative electrode slurry, characterized in that, The negative electrode slurry contains the compound according to any one of claims 1-8 or the carbon material dispersion according to claim 10; Preferably, in the negative electrode slurry, the content of the compound is 0.005-1 wt% of the solid content in the negative electrode slurry.

14. A method for preparing the negative electrode slurry as described in claim 13, characterized in that, The preparation method includes: The compound is mixed with the remaining components of the negative electrode slurry to obtain the negative electrode slurry; Alternatively, the preparation method includes: The carbon material dispersion is mixed with the remaining components of the negative electrode slurry, excluding the conductive agent, to obtain the negative electrode slurry. Preferably, the mixing method includes at least one of homogenous mixing, ball milling, or planetary mixing; Preferably, the amount of the compound added is 0.005-1 wt% of the solid content in the negative electrode slurry. Preferably, the amount of carbon material dispersion added is such that the mass of the compound is 0.005-1 wt% of the solid content in the negative electrode slurry.

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