Block type dispersing agent, preparation method, electrode slurry, electrode pole piece and battery

Abstract

The invention discloses a block type dispersing agent, a preparation method, electrode slurry, an electrode pole piece and a battery. The block type dispersing agent contains an AB type block structure as shown in a general formula (I): # imgabs0 #. The preparation method comprises the following steps: step 1, carrying out a copolymerization reaction on an RAFT reagent as shown in a formula (I ') and a monomer M-b as shown in a formula (III'); and 2, carrying out a copolymerization reaction on the product obtained in the step 1 and a monomer M-a shown in a formula (II '). The block type dispersing agent can be applied to electrode slurry. The block type dispersant can be used for electrode slurry, and has excellent dispersion viscosity reduction and viscosity stabilization effects. The prepared electrode slurry is further applied to an electrode plate of a battery, so that the battery has excellent performance.

Description

Technical Field

[0001] The invention relates to a block type dispersant, a preparation method, an electrode slurry, an electrode plate and a battery. Background Art

[0002] In recent years, with the development of the new energy industry, carbon materials such as carbon nanotubes, graphene, and conductive carbon black have been widely used.

[0003] Due to the special particle structure and surface morphology of this type of carbon material, when no dispersant is used or traditional polyvinyl pyrrolidone dispersants are used, the prepared carbon material slurry will have problems such as inability to disperse or poor dispersion, high slurry viscosity, and short storage time, which will affect subsequent use. Summary of the invention

[0004] In order to overcome the problems in the prior art that carbon material slurry cannot be dispersed or has poor dispersibility, high slurry viscosity, short storage time, etc., the present invention provides a block dispersant, a preparation method, an electrode slurry, an electrode plate and a battery. The block dispersant of the present invention can be used for electrode slurry and has excellent dispersing, viscosity reducing and stabilizing effects.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a block dispersant comprising an AB type block structure as shown in general formula (I):

[0007]

[0008] in,

[0009] Z is -C6H5, -S-C6H5, -C 12 H 25 , C 12 H 25 S-、C4H9S-、

[0010]

[0011] R1 is -CH2C6H5,

[0012] The A block contains a repeating unit-a represented by the general formula (II):

[0013]

[0014] In each repeating unit-a,

[0015] R2 is each independently -H or -CH3;

[0016] R3 is each independently C8-C 18 The alkyl group;

[0017] The B block contains repeating units represented by the general formula (III):

[0018]

[0019] In each repeating unit-b,

[0020] R4 and R5 are each independently -H or -CH3;

[0021] R6 are each independently -H or C1-C8 alkyl;

[0022] f is each independently 8-30.

[0023] In the present invention, "in each ..., ... are each independently ..." means that in the molecular chain of the block dispersant, in different repeating units represented by the same general formula, the groups represented by the same symbol may be the same or different.

[0024] For example, "In each repeating unit-a, R2 is independently -H or -CH3" means that in the molecular chain of the block dispersant, in the repeating unit-a, R2 can be the same or different. Similarly, each repeating unit-b and repeating unit-c have the above meanings.

[0025] For another example, it is necessary to explain that "in each repeating unit -b, R4 and R5 are each independently -H or -CH3; R6 is each independently -H or a C1-C8 alkyl group; f is each independently 8-30;" means that in the molecular chain of the block dispersant, in different repeating units -b, "f" in formula (III) can be the same or different; f In the above, R5 may be the same or different.

[0026] In the present invention, Z is preferably C 12 H 25 S- or HOOC(CH2)2S-.

[0027] In the present invention, in each repeating unit-a, R3 is preferably C 12 -C 18 of alkyl.

[0028] In the present invention, in each repeating unit -a, R3 is preferably -C8H 17 , -C 12 H 25 , -C 16 H 33 or -C18 H 35 .

[0029] In certain specific embodiments, in each repeating unit -a, R2 is -CH3; R3 is C 18 of alkyl.

[0030] In certain specific embodiments, in each repeating unit -a, R2 is -H; R3 is C 18 of alkyl.

[0031] In certain specific embodiments, in each repeating unit -a, R2 is -H; R3 is C 12 of alkyl.

[0032] In certain specific embodiments, in each repeating unit -a, R2 is -CH3; R3 is C 12 of alkyl.

[0033] In certain specific embodiments, in each repeating unit -b, R4 is -CH3; R5 is -H; and R6 is -CH3.

[0034] In the present invention, the A block and / or the B block may further contain a repeating unit -c represented by the general formula (IV):

[0035]

[0036] In each repeating unit-c,

[0037] R7 are each independently -H or -CH3;

[0038] R8 is each independently -H or -CH2CH2N(CH3)2.

[0039] In the present invention, the weight average molecular weight of the block dispersant may be 5000-80000 g / mol, preferably 30000-35000 g / mol, for example 30078 g / mol, 30636 g / mol, 31167 g / mol, 31209 g / mol, 31736 g / mol, 31892 g / mol, 32067 g / mol, 32106 g / mol, 32481 g / mol, 32892 g / mol, 33372 g / mol or 34372 g / mol.

[0040] In the present invention, the number average molecular weight of the block dispersant may be 5000-80000 g / mol, preferably 23000-26000 g / mol, for example 23990 g / mol, 24090 g / mol, 24135 g / mol, 24139 g / mol, 24246 g / mol, 24439 g / mol, 24345 g / mol, 24537 g / mol, 24646 g / mol, 24855 g / mol, 24887 g / mol or 25439 g / mol.

[0041] In the present invention, the molecular weight distribution index (PDI) of the block dispersant is preferably less than 1.5, such as 1.25, 1.27, 1.28, 1.29, 1.31, 1.32, 1.35 or 1.37.

[0042] In the present invention, the weight average molecular weight of the A block may be 2500-40000 g / mol, wherein the weight average molecular weight of the A block is less than the weight average molecular weight of the block type dispersant.

[0043] In the present invention, the longer the carbon chain in the A block is, the stronger the interaction with the carbon material is, and the more the dispersant polymer can be adsorbed on the carbon material, which is beneficial to the dispersion performance.

[0044] In the present invention, the repeating units -a in the A block may be randomly distributed.

[0045] In the present invention, the weight average molecular weight of the B block may be 2500-40000 g / mol, wherein the weight average molecular weight of the B block is less than the weight average molecular weight of the block type dispersant.

[0046] In the present invention, the repeating units -b in the B block may be randomly distributed.

[0047] In a second aspect, the present invention provides a method for preparing a block dispersant, comprising the following steps:

[0048] Step 1, copolymerizing the RAFT agent represented by formula (I') and the monomer Mb represented by formula (III');

[0049]

[0050] Wherein, Z and R1 are Z and R1 as described above;

[0051]

[0052] wherein R4, R5 and R6 are as described above;

[0053] Step 2, copolymerizing the product obtained in step 1 with the monomer Ma represented by formula (II');

[0054]

[0055] Wherein, R2 and R3 are R2 and R3 as described above.

[0056] In the present invention, the RAFT agent may be 2-[[(2-carboxyethyl)sulfanylthiocarbonyl]-sulfanyl]propionic acid 2-[(Dodecylthiocarbonylthio)propanoic acid 4-Cyano-4-[[(dodecylthio)thionemethyl]thio]pentanoic acid

[0057] 4-((((2-Carboxyethyl)thio)carbonylthio)thio)-4-cyanovaleric acid S-(2-Cyano-2-propyl)-S-dodecyl trithiocarbonyl ester S-(2-Cyano-2-butyl)-S-dodecyl trithiocarbonyl ester 2-[n-Butyltrithiocarbonate]propanoic acid 4-Cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanol or 4-cyano-4-[[(dodecylthio)thionemethyl]thio]pentanoic acid methyl ester

[0059] In the present invention, the amount of the RAFT agent used may be 0.5%-5% of the total mass of the monomers in step 1 and step 2, for example 0.85% or 1.35%.

[0060] In the present invention, the amount of the monomer Mb can be 1%-65% of the total mass of the monomers in step 1 and step 2, for example, 45%, 55% or 65%.

[0061] In the present invention, the monomer Mb may be an acrylic acid methoxy-terminated polyether monomer.

[0062] The corresponding polyether in the acrylic acid methoxy-terminated polyether monomer may be polyethylene glycol monomethyl ether, polypropylene glycol monomethyl ether or poly(ethylene oxide-propylene oxide) monomethyl ether.

[0063] In the present invention, the amount of the monomer Ma used can be 1%-50% of the total mass of the monomers in step 1 and step 2, such as 25%, 35% or 45%.

[0064] In the present invention, a monomer Mc, such as an acrylic acid monomer, a methacrylic acid monomer or a dimethylaminoethyl methacrylate monomer, may be additionally added in step 1 or step 2.

[0065] Wherein, the amount of the monomer Mc used can be 10% of the total mass of the monomers in step 1 and step 2.

[0066] In the present invention, the operation and conditions of the copolymerization reaction in step 1 and step 2 are carried out according to the conventional operation and conditions of such reactions in the art.

[0067] In the present invention, the copolymerization reaction in step 1 and step 2 can be carried out under a protective atmosphere, wherein the protective atmosphere refers to a gas atmosphere that does not react with the reaction system, such as nitrogen or an inert gas.

[0068] In the present invention, the copolymerization reaction in step 1 and step 2 can be carried out in a solvent, and the solvent is any solvent applicable in the art, such as water, alcohol solvents, ester solvents, ketone solvents, amide solvents or aromatic hydrocarbon solvents.

[0069] Wherein, the ketone solvent may be N-methylpyrrolidone.

[0070] Wherein, the amide solvent may be N,N-dimethylformamide.

[0071] The total amount of the solvent in step 1 and step 2 can be selected according to the applicable range in the art, and is preferably 1-10 times, for example 1.01 times, the total mass of the monomers in step 1 and step 2.

[0072] In the present invention, the copolymerization reaction in step 1 and step 2 can be carried out in the presence of an initiator.

[0073] The initiator may be 2,2-azobisisobutylamidine dihydrochloride, azobisisoheptanenitrile, azobisisovaleronitrile, dimethyl azobisisobutyrate, 2,2-azabis(2-imidazoline) dihydrochloride, 1,1-azo(cyanocyclohexane), 4,4-azobis(4-cyanovaleric acid), 2,2-azobis(4-methoxy-2,4-dimethylvaleronitrile), azobisisobutyronitrile, azobisimidazoline propane, 2,2-azobis(N-butyl-2-methylpropionamide), 2,2-azobis(2-imidazoline) dihydrochloride, 1,1-azo(cyanocyclohexane), 4,4-azobis(4-cyanovaleric acid), 2,2-azobis(4-methoxy-2,4-dimethylvaleronitrile), azobisisobutyronitrile, azobisimidazoline propane, 2,2-azobis(N-butyl-2-methylpropionamide), 2,2-azobis(2-imidazoline) N-(2-methyl-N-(2-hydroxyethyl)propionamide), tert-butyl peroxypivalate, tert-butyl peroxyisobutyrate, tert-butyl peroxy(2-ethylhexanoate), 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butylperoxy-3,5,5-trimethylhexanoate, di-tert-butyl peroxide, dibenzoyl peroxide, tert-butyl hydroperoxide, diisopropylbenzene peroxide, dilauroyl peroxide, tert-butyl isopropylbenzene peroxide or 1,4-di-tert-butylperoxyisopropylbenzene.

[0074] Among them, the amount of the initiator in the step 1 or the amount of the initiator in the step 2 can be selected according to the applicable range in the art, preferably 0.01%-0.5% of the total mass of the monomers in the step 1 or the total mass of the monomers in the step 2, for example, 0.08%, 0.10%, 0.12%, 0.13%, 0.16% or 0.20%.

[0075] In the present invention, in step 1 and step 2, the temperature of the copolymerization reaction is independently determined according to the applicable temperature of such reaction, preferably 40-100°C, such as 78°C.

[0076] In the present invention, in the step 1 and the step 2, the time of the copolymerization reaction is independently suitable for the completion of the reaction, preferably 1-8h, such as 3.5h.

[0077] In a third aspect, the present invention provides a block dispersant obtained by the preparation method as described above.

[0078] In a fourth aspect, the present invention provides an electrode slurry comprising the block dispersant as described above, a solvent and an electrode material.

[0079] In the present invention, the solvent may be NMP.

[0080] In the present invention, the electrode material may be a carbon material.

[0081] Wherein, the carbon material may be graphene, carbon nanotube or conductive carbon black.

[0082] In the present invention, the mass proportion of the carbon material may be 3%-4%, for example 3.5%, of the mass of the electrode slurry.

[0083] In the present invention, the mass proportion of the block dispersant may be 0.5%-1.0% of the mass of the electrode slurry, for example, 0.875%.

[0084] In a fifth aspect, the present invention provides an electrode plate, which is made using the electrode slurry as described above.

[0085] In the present invention, the method for preparing an electrode plate using the electrode slurry can be conventional in the art, and generally comprises: coating the electrode slurry on at least one surface of a current collector, and drying.

[0086] In a sixth aspect, the present invention provides a battery comprising the electrode plate as described above.

[0087] In the present invention, the battery is preferably a lithium ion battery.

[0088] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention. The reagents and raw materials used in the present invention are all commercially available.

[0089] The positive and progressive effects of the present invention are:

[0090] (1) The molecular structure of the block polymer of the present invention has an anchoring group that can be adsorbed with the electrode material to enhance stability, and a solvation chain that can interact with the solvent to enhance the solubility of the electrode material. Due to its special block structure, the electrode material can be stably dispersed;

[0091] (2) The block polymer dispersant of the present invention makes the obtained electrode slurry have low viscosity, excellent dispersion effect, good fluidity and good stability; the prepared electrode slurry is further used in the electrode plate of the battery, so that the battery has excellent performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0092] Figure 1 This is the GPC spectrum of the intermediate product containing block B in Example 1;

[0093] Figure 2 This is the GPC spectrum of the final product in Example 1. DETAILED DESCRIPTION

[0094] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0095] In the following examples and comparative examples:

[0096] Molecular weight and molecular weight distribution index (PDI)

[0097] The molecular weight (weight average molecular weight, number average molecular weight) and molecular weight distribution index of the polymer were tested by using a Waters 1515 gel permeation chromatograph, calibrated with standard polystyrene, and using N-methylpyrrolidone as the mobile phase at a column temperature of about 90°C.

[0098] Example 1

[0099] Step 1. Add 2.69g 4-cyano-4-[[(dodecylthio)thiomethyl]thio]pentanoic acid and 19.9g N-methylpyrrolidone to a 500ml four-necked round-bottom flask, install the condenser, thermometer, feeding tube and nitrogen tube, then turn on the mechanical stirrer, and introduce nitrogen for deoxygenation for 30 minutes, and heat to 78°C. Start to drop a mixed solution containing 90g polyethylene glycol 400 monomethyl ether methacrylate and 0.11g azobisisobutyronitrile, drop for 1.5 hours, and continue to keep warm for 3.5 hours after the dropwise addition is completed. In this step, the GPC spectrum of the reaction product is as follows Figure 1 shown.

[0100] Step 2: After the heat preservation is completed, a mixed solution containing 90 g of octadecyl methacrylate, 20 g of dimethylaminoethyl methacrylate, 0.14 g of azobisisobutyronitrile and 183 g of N-methylpyrrolidone is added dropwise for 1.5 minutes. After the addition is completed, the heat preservation reaction is continued for 3.5 hours. The GPC spectrum of the final product is shown in FIG. Figure 2 As shown, Figure 1 and Figure 2 By comparison, it can be seen that the molecular weight has increased, and there is only a single peak, and the molecular weight distribution is narrow, which can prove that the final product is a block distribution.

[0101] Example 2-12

[0102] Compared with Example 1, the only difference is that the types and amounts of some monomer raw materials are different, as shown in Table 1 and Table 2 for details.

[0103] Comparative Example 1

[0104] In a 500 ml four-necked round-bottom flask, add 2.69 g of 4-cyano-4-[[(dodecylthio)thioketonemethyl]thio]pentanoic acid and 203 g of N-methylpyrrolidone, install a condenser, thermometer, feeding tube and nitrogen tube, then turn on the mechanical stirrer, introduce nitrogen to deoxygenate for 30 minutes, and heat to 78°C.

[0105] A mixed solution containing 90 g of polyethylene glycol 400 monomethyl ether methacrylate, 90 g of octadecyl methacrylate, 20 g of methacrylic acid and 0.25 g of azobisisobutyronitrile was added dropwise for 1.5 hours, and after the addition was completed, the reaction was continued at the temperature for 3.5 hours. After cooling and discharging, a non-blocked but narrowly distributed polymer was obtained.

[0106] Comparative Example 2

[0107] Add 200 g of N-methylpyrrolidone to a 500 ml four-necked round-bottom flask, install the condenser, thermometer, feeding tube and nitrogen tube, then turn on the mechanical stirrer, introduce nitrogen to deoxygenate for 30 minutes, and heat to 78°C.

[0108] A mixed solution containing 90 g of polyethylene glycol 400 monomethyl ether methacrylate, 90 g of octadecyl methacrylate, 20 g of methacrylic acid and 0.6 g of azobisisobutyronitrile was added dropwise for 1.5 hours, and after the addition was completed, the reaction was continued at the temperature for 3.5 hours. After cooling and discharging, a non-blocked polymer with a wide distribution was obtained.

[0109] Table 1 Raw materials and products of Examples 1-6

[0110]

[0111] Table 2 Raw materials and products of Examples 7-12

[0112]

[0113] Application Examples

[0114] The block polymers obtained in Examples 1-12 are used as dispersants for carbon nanotube slurry. Comparative Examples 1-2 and a commonly used dispersant on the market, polyvinyl pyrrolidone (PVP K30), are used for comparison.

[0115] Test method: NMP was used as solvent, based on mass, 0.875% dispersant was added to a carbon nanotube addition amount of 3.5%, and the mixture was shaken for 8 hours. The properties of the carbon nanotube slurry are shown in Table 3.

[0116] Test method: Anton Paar MCR 92 rheometer was used with PP50 as the rotor to test its rheological properties, and the viscosity at 20.8 rpm and 57.0 rpm was compared.

[0117] Among them, the specific properties of carbon nanotubes are shown in Table 3:

[0118] Table 3 Specific properties of carbon nanotubes

[0119] Specific surface area Pipe diameter length <![CDATA[300m 2 / g]]> 7-12 nm 50nm

[0120] Table 4 Dispersion performance data of carbon nanotube slurry in application examples

[0121]

[0122] From the comparison between Example 1 and Example 2, it can be seen that the additional addition of dimethylaminoethyl methacrylate in the preparation of block A has a more limited effect on the improvement of dispersibility than the additional addition of methacrylic acid. Because the object dispersed in the present invention generally does not have an acidic group, the functional group with N on the dispersant can serve as a good anchoring group.

[0123] From the comparison between Example 2 and Example 3, it can be seen that the use of polyethylene glycol 400 monomethyl ether methacrylate in the preparation of the B block has a more significant improvement in the dispersion performance than the use of polyethylene glycol 750 monomethyl ether methacrylate.

[0124] It can be seen from the comparison between Example 2, Example 4 and Example 5 or from the comparison between Example 10 and Example 11 that the greater the A block content is, the more beneficial it is to the dispersion performance.

[0125] From the comparison between Example 2 and Example 6 or from the comparison between Example 8 and Example 12, it can be seen that the additional addition of acrylic monomers in the preparation of block A can improve the dispersion performance more significantly than the additional addition of acrylic monomers in the preparation of block B. Because block A is an anchoring block and block B is a solvating chain block, the acrylic monomer is additionally added to block A, so that block A has not only alkyl acrylate, but also polar anchoring groups such as acrylic acid or methacrylic acid. In this way, the dispersant polymer can form two blocks, namely the anchoring block and the solvating chain block, so that one end of the dispersant polymer can be anchored on the dispersed object and the other end can be used as a solvating chain. On the contrary, if additional acrylic acid or methacrylic acid is added to block B, the solvating chain block will have an anchoring group, so that the improvement of dispersion performance is relatively limited.

[0126] From the comparison between Example 2 and Example 7 or from the comparison between Example 8 and Example 9, it can be seen that when the chain length of R3 is longer, the improvement of the dispersion performance is more significant.

[0127] In summary, from the data in Table 4, it can be seen that the block polymer dispersant of the present invention has a good dispersion and viscosity reduction effect and storage stability for carbon nanotubes in polar solvents, and can exceed the level of PVP K30 in terms of dispersion and viscosity reduction and storage stability.

[0128] The block polymer of the present invention has an anchoring group in its molecular structure that can absorb and enhance stability with carbon nanotubes, and a solvation chain that can interact with polar solvents to enhance the solubility of carbon nanotubes. Due to its special block structure, the carbon nanotubes can be stably dispersed.

[0129] The block polymer dispersant of the present invention enables the obtained carbon nanotube slurry to have low viscosity, excellent dispersion effect, good fluidity and good stability; the prepared carbon nanotube slurry can be further used in the preparation of electrode materials.

[0130] The above embodiments are only preferred implementation modes of the present invention and are only used to explain the present invention rather than to limit the present invention. Any changes, substitutions, modifications, etc. made by those skilled in the art without departing from the spirit of the present invention should fall within the scope of protection of the present invention.

Claims

1. A block dispersant, characterized in that: It contains an AB type block structure as shown in the general formula (I): in, Z is -C6H5, -S-C6H5, -C 12 H 25 , C 12 H 25 S-, C4H9S-, HOOC(CH2)2S-, HOOCCH(CH3)S-, CH3OOCCH(CH3)S- or HOOCCH2CH2CN(CH3)S-; R1 is -CH2C6H5, HOOC(CH2)2-, -C(CH3)CNCH2CH2COOH, -C(CH3)2CN, -C(CH3)CNCH2CH2CH2OH, -CH(CH3)CNC2H5 or -C(CH3)CNCH2CH2COOCH3; The A block contains a repeating unit-a represented by the general formula (II): In each repeating unit-a, R2 is each independently -H or -CH3; R3 is each independently C8-C 18 The alkyl group; The B block contains a repeating unit -b represented by the general formula (III): In each repeating unit-b, R4 and R5 are each independently -H or -CH3; R6 are each independently -H or C1-C8 alkyl; f is each independently an integer of 8-30.

2. The block dispersant according to claim 1, characterized in that Z is C 12 H 25 S- or HOOC(CH2)2S-; And / or, in each repeating unit-a, R2 and R3 each independently satisfy any one of the following conditions: ①R2 is -CH3; R3 is C 18 The alkyl group; ②R2 is -H; R3 is C 18 The alkyl group; ③R2 is -H; R3 is C 12 The alkyl group; ④R2 is -CH3; R3 is C 12 The alkyl group; ⑤R3 is C 12 -C 18 The alkyl group; ⑥R3 is -C8H 17 , -C 12 H 25 , -C 16 H 33 or -C 18 H 35 ; and / or, in each repeating unit -b, R4 is -CH3; R5 is -H; R6 is -CH3; And / or, the A block and / or the B block further contains a repeating unit -c represented by the general formula (IV): In each repeating unit-c, R7 are each independently -H or -CH3; R8 are each independently -H or -CH2CH2N(CH3)2; and / or, the block dispersant has a weight average molecular weight of 5000-80000 g / mol, preferably 30000-35000 g / mol, for example 30078 g / mol, 30636 g / mol, 31167 g / mol, 31209 g / mol, 31736 g / mol, 31892 g / mol, 32067 g / mol, 32106 g / mol, 32481 g / mol, 32892 g / mol, 33372 g / mol or 34372 g / mol; and / or, the number average molecular weight of the block dispersant may be 5000-80000 g / mol, preferably 23000-26000 g / mol, for example 23990 g / mol, 24090 g / mol, 24135 g / mol, 24139 g / mol, 24246 g / mol, 24439 g / mol, 24345 g / mol, 24537 g / mol, 24646 g / mol, 24855 g / mol, 24887 g / mol or 25439 g / mol; and / or, the molecular weight distribution index of the block dispersant is less than 2.0, for example, 1.25, 1.27, 1.28, 1.29, 1.31, 1.32, 1.35 or 1.37; and / or, the weight average molecular weight of the A block is 2500-40000 g / mol; And / or, the repeating units -a in the A block are randomly distributed; and / or, the weight average molecular weight of the B block is 2500-40000 g / mol; And / or, the repeating units -b in the B block are randomly distributed.

3. A method for preparing a block dispersant, characterized in that: It includes the following steps: Step 1, copolymerizing the RAFT agent represented by formula (I') and the monomer Mb represented by formula (III'); Wherein, Z and R1 are as defined in claim 1 or 2; Wherein, R4, R5 and R6 are as defined in claim 1 or 2; Step 2, copolymerizing the product obtained in step 1 with the monomer Ma represented by formula (II'); Wherein, R2 and R3 are as defined in claim 1 or 2.

4. The method for preparing a block dispersant according to claim 3, characterized in that: The RAFT agent is 2-[[(2-carboxyethyl)sulfanylthiocarbonyl]-sulfanyl]propionic acid, 2-[(dodecylthiocarbonyl)sulfur]propionic acid, 4-cyano-4-[[(dodecylthio)thioketonemethyl]thio]pentanoic acid, 4-((((2-carboxyethyl)thio)thiocarbonyl)thio)-4-cyanopentanoic acid, S-(2-cyano-2-propyl)-S-dodecyltrithiocarbonyl ester, S-(2-cyano-2-butyl)-S-dodecyltrithiocarbonyl ester, 2-[n-butyltrithiocarbonate]propionic acid, 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanol or 4-cyano-4-[[(dodecylthio)thioketonemethyl]thio]pentanoic acid methyl ester; And / or, the amount of the RAFT agent used is 0.5%-5% of the total mass of the monomers in step 1 and step 2, for example 0.85% or 1.35%; And / or, the amount of the monomer Mb is 1%-65% of the total mass of the monomers in step 1 and step 2, for example 45%, 55% or 65%; And / or, the monomer Mb is an acrylic acid methoxy-terminated polyether monomer; the corresponding polyether in the acrylic acid methoxy-terminated polyether monomer is preferably polyethylene glycol monomethyl ether, polypropylene glycol monomethyl ether or poly(ethylene oxide-propylene oxide) monomethyl ether; And / or, the amount of the monomer Ma is 1%-50% of the total mass of the monomers in step 1 and step 2, for example, 25%, 35% or 45%; And / or, in step 1 or step 2, a monomer Mc is additionally added, such as an acrylic acid monomer, a methacrylic acid monomer or a dimethylaminoethyl methacrylate monomer; the amount of the monomer Mc is preferably 10% of the total mass of the monomers in step 1 and step 2.

5. The method for preparing a block dispersant according to claim 3, characterized in that: The copolymerization reactions in step 1 and step 2 are both carried out under a protective atmosphere; the protective atmosphere is preferably nitrogen or an inert gas; And / or, the copolymerization reactions in step 1 and step 2 are both carried out in a solvent; the solvent is preferably water, an alcohol solvent, an ester solvent, a ketone solvent, an amide solvent or an aromatic hydrocarbon solvent; the ketone solvent is more preferably N-methylpyrrolidone; the amide solvent is more preferably N,N-dimethylformamide; the total amount of the solvent in step 1 and step 2 is preferably 1-10 times the total mass of the monomers in step 1 and step 2, for example 1.01 times; And / or, the copolymerization reaction in step 1 and step 2 is carried out in the presence of an initiator; the initiator is preferably 2,2-azobisisobutylamidine dihydrochloride, azobisisoheptanenitrile, azobisisovaleronitrile, dimethyl azobisisobutyrate, 2,2-azabis(2-imidazoline) dihydrochloride, 1,1-azo(cyanocyclohexane), 4,4-azobis(4-cyanovaleric acid), 2,2-azobis(4-methoxy-2,4-dimethylvaleronitrile), azobisisobutyronitrile, azobisimidazoline propane, 2,2-azobis(N-butyl-2-methylpropionamide), 2,2-azo(2-methyl-N-(2-hydroxyethyl)propionamide), tert-butyl peroxypivalate, isocyanate peroxide tert-butyl butyrate, tert-butyl peroxide (2-ethylhexanoate), 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl peroxy-3,5,5-trimethylhexanoate, di-tert-butyl peroxide, dibenzoyl peroxide, tert-butyl hydroperoxide, diisopropylbenzene peroxide, dilauroyl peroxide, tert-butyl isopropylbenzene peroxide or 1,4-di-tert-butyl peroxy isopropylbenzene; the amount of the initiator in step 1 or the amount of the initiator in step 2 is preferably 0.01%-0.5% of the total mass of the monomers in step 1 or the total mass of the monomers in step 2, for example, 0.08%, 0.10%, 0.12%, 0.13%, 0.16% or 0.20%; And / or, in step 1, the copolymerization reaction temperature is 40-100° C., for example 78° C.; And / or, in step 1, the copolymerization reaction time is 1-8h, for example 3.5h; And / or, in step 2, the copolymerization reaction temperature is 40-100° C., for example 78° C.; And / or, in step 2, the copolymerization reaction time is 1-8 hours, for example 3.5 hours.

6. A block dispersant, characterized in that: The dispersant is obtained by the method for preparing the block dispersant according to any one of claims 3 to 5.

7. An electrode slurry, characterized in that: It comprises the block dispersant as described in any one of 1, 2 and 6, a solvent and an electrode material.

8. The electrode slurry according to claim 7, characterized in that: The solvent is NMP; And / or, the electrode material is a carbon material; the carbon material is preferably graphene, carbon nanotubes or conductive carbon black; And / or, the mass of the electrode material accounts for 3%-4% of the mass of the electrode slurry, for example, 3.5%; And / or, the mass proportion of the block dispersant is 0.5%-1.0% of the mass of the electrode slurry, for example 0.875%.

9. An electrode plate, characterized in that: The electrode is prepared using the electrode slurry as claimed in claim 7 or 8.

10. A battery, characterized in that: It includes the electrode plate as claimed in claim 9.

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