A method for preparing a conductive adhesive, a battery electrode and a battery

Abstract

The present invention relates to a method for preparing a conductive adhesive, a battery pole piece and a battery, the method comprising the following steps: step 1, preparing modified carbon nanotubes; step 2, dispersing the modified carbon nanotubes in step 1 in water to obtain a second modified carbon nanotube aqueous dispersion; step 3, adding an acrylic multi-polymer to the second modified carbon nanotube aqueous dispersion prepared in step 2, and mechanically mixing to obtain. The present invention improves the dispersion level of carbon nanotubes in the adhesive, and improves the peel strength and electrochemical performance of the electrode material.

Description

Technical Field

[0001] The invention belongs to the technical field of energy storage, and in particular relates to a method for preparing a conductive adhesive, a battery pole piece and a battery. Background Art

[0002] Carbon nanotubes are one-dimensional tubular nanomaterials formed by curling single or multiple layers of graphite. They have many superior properties. When applied to electrode slurries, they have higher electronic conductivity than traditional conductive agents such as conductive carbon black, conductive graphite, and conductive carbon fiber. In addition, carbon nanotubes can effectively improve the battery's large current discharge capability and significantly increase the battery capacity. Their excellent thermal conductivity is also beneficial to the heat dissipation during the battery's charging and discharging process, reducing electrode polarization, improving the battery's high and low temperature performance, and extending the battery's cycle life. Therefore, carbon nanotubes have attractive application prospects in lithium-ion power battery electrodes.

[0003] However, there are currently two common methods for applying carbon nanotubes to electrode slurries: 1) When preparing electrode slurry, the carbon nanotubes are first dispersed in water, and then the aqueous dispersion of the carbon nanotubes is added to the electrode slurry. For the electrode slurry prepared by this method, no matter how well the carbon nanotubes are dispersed in the aqueous solution during the preparation process, once they are added to the electrode slurry, due to changes in the system, the carbon nanotubes are easily entangled and agglomerated with each other under the action of van der Waals forces, resulting in uneven dispersion in the electrode slurry, thereby affecting the performance of various aspects of the carbon nanotubes in the electrode slurry, such as conductivity. 2) First add the carbon nanotubes to the binder, and use the carboxyl groups of the carbon nanotubes and the carboxyl groups, cyano groups, etc. in the binder to form a three-dimensional network structure under the action of hydrogen bonding forces. Then, add the binder with the three-dimensional network structure to the electrode slurry. At this time, the carbon nanotubes are coated and blocked by the binder, so that the carbon nanotubes are effectively dispersed in the electrode slurry and the agglomeration of the carbon nanotubes is avoided. Although this method can solve the dispersion problem of carbon nanotubes in the electrode slurry, it concentrates the dispersion difficulty on the dispersion of carbon nanotubes in the binder. Therefore, it is particularly important to prepare a lithium battery negative electrode binder to achieve effective dispersion of carbon nanotubes in the binder, thereby improving the electrochemical properties of the electrode in all aspects. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects in the prior art and provide a method for preparing a conductive adhesive, a battery pole piece and a battery, which improve the dispersion level of carbon nanotubes in the adhesive and improve the peel strength and electrochemical performance of the electrode material.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] Technical solution 1:

[0007] A method for preparing a conductive adhesive comprises the following steps:

[0008] Step 1, preparing modified carbon nanotubes;

[0009] Step 2, dispersing the modified carbon nanotubes in step 1 in water to obtain a second modified carbon nanotube aqueous dispersion;

[0010] Step 3: Add the binder polymer containing the acrylic multipolymer to the second modified carbon nanotube aqueous dispersion prepared in step 2, and mix them mechanically to obtain a conductive binder.

[0011] As a preferred technical solution, after step 3, the following steps are further included:

[0012] Step 4: Concentrate the conductive adhesive obtained in step 3 by rotary evaporation to obtain a concentrated conductive adhesive.

[0013] As a preferred technical solution, the preparation of modified carbon nanotubes in step 1 comprises the following steps:

[0014] The oxidant is dissolved in water to obtain an oxidant aqueous solution; the carbon nanotubes are added to the oxidant aqueous solution and ultrasonicated for 1-5 hours to obtain a first mixed solution; the first mixed solution is stirred at 20-80°C for 2-48 hours to obtain a first modified carbon nanotube aqueous dispersion; then, the first modified carbon nanotube aqueous dispersion is filtered and washed to obtain the modified carbon nanotubes. As a preferred technical solution, the mass percentage concentration of the oxidant aqueous solution is 0.01%-0.5%.

[0015] As a preferred technical solution, the carbon nanotubes are added to the aqueous oxidant solution, in parts by weight, the carbon nanotubes are 1 part, and the aqueous oxidant solution is 100-400 parts.

[0016] As a preferred technical solution, the oxidant is one or a mixture of two or more of inorganic persulfate oxide, peroxide, hydrogen peroxide or potassium permanganate.

[0017] As a preferred technical solution, the step of dispersing the modified carbon nanotubes in water in step 2 specifically includes:

[0018] The modified carbon nanotubes are placed in deionized water to obtain a second mixed solution, and the second mixed solution is ultrasonicated using a cell disruptor to obtain the second modified carbon nanotube aqueous dispersion.

[0019] As a preferred technical solution, the ratio of carbon nanotubes to deionized water is 1:500-5000 in parts by weight.

[0020] As a preferred technical solution, the ultrasonic frequency of the cell disruptor is 10-50 Hz.

[0021] As a preferred technical solution, the acrylic multipolymer in step 3 is a terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid.

[0022] As a preferred technical solution, in step 3, an acrylic multipolymer is added to the second modified carbon nanotube aqueous dispersion in step 2, and the ratio of carbon nanotubes to the acrylic multipolymer is 1:10-50 by weight.

[0023] As a preferred technical solution, the modified carbon nanotubes in step 1 are single-walled carbon nanotubes.

[0024] Technical solution 2:

[0025] A conductive adhesive, characterized in that it is prepared by using the conductive adhesive preparation method.

[0026] Technical solution three:

[0027] An electrode plate contains the conductive adhesive.

[0028] Technical solution 4:

[0029] A battery is provided with the electrode plate.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention uses a low-concentration modified carbon nanotube dispersion and a low-concentration acrylic copolymer to blend, and then prepares a binder by a rotary evaporation concentration method. Since a high-concentration (solid content>0.5‰) modified carbon nanotube dispersion cannot achieve good dispersion in the acrylic copolymer bonding system, and since the carbon tubes in the high-concentration modified carbon nanotube dispersion are more densely distributed, when the acrylic copolymer is added, the acrylic copolymer molecules cannot be well dispersed between the carbon tubes of the single-walled carbon nanotube dispersion, thereby causing phase separation. The present invention adds the acrylic multipolymer to the modified carbon nanotube dispersion in a low concentration (solid content <0.5‰) state. Compared with the carbon nanotube dispersion added in a high concentration state, the acrylic multipolymer molecules can be better dispersed between the carbon nanotubes to form a homogeneous dispersion, so that the system is in a good dispersion state and is not easy to agglomerate. However, since the binder prepared by blending in a low concentration state cannot meet the requirements of subsequent use, the present invention adds a rotary evaporation concentration process that does not affect the dispersion state of the carbon nanotubes, removes part of the solvent in the system, and makes its concentration meet the requirements of subsequent use.

[0032] The present invention performs oxidation modification on single-walled carbon nanotubes. On the one hand, without destroying the morphology of the carbon nanotubes, active groups such as carbonyl and carboxyl grow on the surface of the carbon nanotubes, thereby improving the dispersion ability of the carbon nanotubes in water and the dispersion effect in the acrylic acid multi-polymer bonding system, so that the carbon nanotubes are distributed in a network on the surface of the silicon material and are almost individually dispersed, thereby achieving better wrapping of the silicon material by the binder. On the other hand, the surface of the oxidized carbon nanotubes is filled with holes, which not only helps the transfer of ions, but also can form a porous electrode structure, reduce the ion transfer resistance of ions in the electrode circulation process, and improve the kinetic performance of the electrode.

[0033] In the oxidation modification process of the single-walled carbon nanotubes, the present invention uses 3% ammonium persulfate for oxidation, which helps to obtain full-length single-walled carbon nanotubes and avoids the breakage of the single-walled carbon nanotubes during the modification process to affect their performance in the binder and the electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a SEM morphology image of the electrode plate material in Example 2 of the present invention;

[0035] Figure 2 This is a SEM morphology of the electrode sheet material in Comparative Example 1 of the present invention;

[0036] Figure 3 is an electrochemical impedance spectrum of the battery of the present invention; DETAILED DESCRIPTION

[0037] In the present invention,

[0038] Single-walled carbon nanotubes: purchased from Aokoshiel Trading (Shenzhen) Co., Ltd.

[0039] Si-C composite material containing Si and C (main material of silicon-carbon negative electrode), silicon-based with a gram capacity of 600mAh / g: Zhejiang Lichen New Material Technology Co., Ltd.;

[0040] PE / PP separator: purchased from Shanghai Enjie New Material Technology Co., Ltd.;

[0041] The binder polymer used in the present invention is a terpolymer containing acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid. The preparation method of the binder polymer comprises the following steps:

[0042] Step a: add 350 parts of pure water to the reactor, stir at 100 rpm, introduce nitrogen at a flow rate of 2000 L / h, remove water-soluble oxygen for 1.5 hours, then add 55 parts of monomer acrylic acid, 5 parts of monomer N, N-diethylacrylamide, and 40 parts of monomer acrylonitrile, continue to introduce nitrogen, stir for 3 hours, and obtain a solution.

[0043] Step b, continuously introducing nitrogen, heating the solution to 55° C. at a heating rate of 1° C. / min, adding 0.5 parts by mass fraction (10%) of an initiator solution of benzoyl peroxide, initiating the reaction for 10 hours, and obtaining a polymer product.

[0044] Step c: reducing the pressure of the polymer product at 60° C. by using a vacuum pump to a vacuum degree lower than 0.1 MPa to remove residual monomers to obtain a polymer product with a solid content of 40%.

[0045] Step d: 500 g of the polymer product having a solid content of 40% is neutralized at 50° C. with 2833.3 g of an aqueous lithium hydroxide alkali solution to a pH of 7.5 to obtain a viscous binder polymer; the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid in the obtained binder polymer is 6%.

[0046] The present invention is further described in detail below with reference to the embodiments.

[0047] When blending in the embodiments or comparative examples of the present invention, the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is added by adding a binder polymer, and the actual amount of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid added is calculated by the formula:

[0048] The amount of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid added = the amount of the binder polymer added × the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid

[0049] When blending in each embodiment or comparative example of the present invention, the carbon nanotubes are added in the form of the second modified carbon nanotube aqueous dispersion (the second modified carbon nanotube aqueous dispersion contains modified carbon nanotubes and unmodified carbon nanotubes), and the amount of carbon nanotubes added = the amount of the second modified carbon nanotube aqueous dispersion added × the solid content of the second modified carbon nanotube aqueous dispersion

[0050] In each embodiment or comparative example of the present invention, the solid content of the conductive adhesive is obtained by calculation;

[0051] Solid content of conductive adhesive % = (the amount of terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid added + the amount of carbon nanotubes added) / (the amount of binder polymer added + the amount of the second modified carbon nanotube aqueous dispersion added) × 100%

[0052] Example 1

[0053] A conductive adhesive, the preparation method of which comprises the following steps:

[0054] Step 1, oxidation modification:

[0055] Step 1-1, take 30.93g of oxidant APS (ammonium persulfate), add 1000g of deionized water, and prepare an oxidant aqueous solution with a mass concentration of 3%;

[0056] Step 1-2, adding 5 g of single-walled carbon nanotubes to an aqueous solution of an oxidant having a mass concentration of 3%, and ultrasonically treating the solution for 2 h using an ultrasonic cleaning machine to obtain a first mixed solution;

[0057] Step 1-3, stirring the first mixed solution at 40° C. and 100 rpm for 6 hours to obtain a first modified carbon nanotube aqueous dispersion;

[0058] Step 1-4, filtering the first modified carbon nanotube aqueous dispersion, washing the filter cake with deionized water until it is neutral, to obtain modified carbon nanotubes;

[0059] Step 2: Dispersion of carbon nanotubes:

[0060] Step 2-1, placing the modified carbon nanotubes prepared in step 1 in 5 kg of deionized water at a ratio of carbon nanotubes to deionized water of 1:1000 by weight, and breaking them up with a disperser to prepare a second mixed solution;

[0061] Step 2-2, the second mixed solution was subjected to ultrasonic treatment at 20 Hz for 4 h using a cell disruptor, and then filtered through a 150-200 mesh filter to obtain a second modified carbon nanotube aqueous dispersion. The solid content of the obtained second modified carbon nanotube aqueous dispersion was determined to be 0.342‰;

[0062] Step 3, blending: in parts by weight, according to the ratio of carbon nanotubes to the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid of 1:44, take 185.6g of the second modified carbon nanotube aqueous dispersion with a solid content of 0.342‰ prepared in step 2, stir at a speed of 1000rpm, then add 46.55g of binder polymer (the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 6%) to the stirred second modified carbon nanotube aqueous dispersion, continue stirring at a speed of 1000rpm for 60min, until it is evenly dispersed, to prepare a conductive adhesive, and it is calculated that the solid content of the prepared conductive adhesive is 1.23%;

[0063] The prepared conductive adhesive is concentrated during the pulping and electrode preparation process to increase its solid content for easy application. Therefore, it also includes:

[0064] Step 4, concentration: The conductive adhesive with a solid content of 1.23% obtained in step 3 is concentrated by rotary evaporation at 70 degrees Celsius to a solid content of 4.5%, thereby obtaining a concentrated conductive adhesive.

[0065] An electrode plate, the preparation method of which comprises the following steps:

[0066] Step a, after mixing a Si-C composite material containing Si and C (a silicon-based material with a gram capacity of 600 mAh / g), conductive graphite, CMC, and a concentrated conductive binder, adding deionized water, dispersing evenly, and passing through a 100-mesh sieve to prepare an electrode slurry with a total solid content of 42%; in the electrode slurry, the electrode material accounts for 96.05wt% of the total solid content, the conductive graphite (SP) accounts for 0.95wt% of the total solid content, the CMC accounts for 0.5wt% of the total solid content, and the concentrated conductive binder accounts for 2.5wt% of the total solid content;

[0067] Step b: coat the electrode slurry on a 10 μm thick copper foil as a current collector, and then dry it at 120°C for 5 minutes. After cooling naturally to room temperature in the furnace, 4 The electrode sheet is obtained by rolling with a unit length load of N / m.

[0068] A battery, the preparation method of which is as follows:

[0069] The electrode plate is used as the negative electrode, nickel cobalt manganese oxide NCM523 is used as the positive electrode, ethylene carbonate EC: ethyl methyl carbonate EMC: diethyl carbonate DEC mixed solvent in a mass ratio of 3:2:5, containing 1M LiPF6, is used as the electrolyte, and a PE / PP diaphragm is used as the diaphragm to make a P383450 lithium-ion battery.

[0070] Example 2

[0071] A conductive adhesive, the preparation method of which comprises the following steps:

[0072] Step 1, oxidation modification:

[0073] Step 1-1, take 30.93g APS (ammonium persulfate), add 1000g deionized water, and prepare an APS aqueous solution with a mass concentration of 3%;

[0074] Step 1-2, adding 5 g of single-walled carbon nanotubes into an APS aqueous solution with a mass concentration of 3%, and ultrasonically treating the solution for 2 h using an ultrasonic cleaning machine to obtain a first mixed solution;

[0075] Step 1-3, stirring the first mixed solution at 40° C. and 100 rpm for 6 hours to obtain a first modified carbon nanotube aqueous dispersion;

[0076] Step 1-4, filtering the first modified carbon nanotube aqueous dispersion, washing the filter cake with deionized water until it is neutral, to obtain modified carbon nanotubes;

[0077] Step 2: Dispersion of carbon nanotubes:

[0078] Step 2-1, placing the modified carbon nanotubes prepared in step 1 in 5 kg of deionized water at a ratio of carbon nanotubes to deionized water of 1:1000 by weight, and breaking them up with a disperser to prepare a second mixed solution;

[0079] Step 2-2, the second mixed solution was subjected to ultrasonic treatment at 20 Hz for 4 h using a cell disruptor, and then filtered through a 150-200 mesh filter to obtain a second modified carbon nanotube aqueous dispersion. The solid content of the obtained second modified carbon nanotube aqueous dispersion was determined to be 0.342‰;

[0080] Step 3, blending: in parts by weight, according to the ratio of carbon nanotubes to the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid of 1:25, take 304.1g of the second modified carbon nanotube aqueous dispersion with a solid content of 0.342‰ prepared in step 2, stir at a speed of 1000rpm, then add 43.34g of binder polymer (the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 6%) to the stirred second modified carbon nanotube aqueous dispersion, continue stirring at a speed of 1000rpm for 60min, until it is evenly dispersed, to prepare a conductive adhesive, and it is calculated that the solid content of the prepared conductive adhesive is 0.78%;

[0081] The prepared conductive adhesive is concentrated during the pulping and electrode preparation process to increase its solid content for easy application. Therefore, it also includes:

[0082] Step 4, concentration: The conductive adhesive with a solid content of 0.78% obtained in step 3 is concentrated by rotary evaporation at 70 degrees Celsius to a solid content of 4.5%, thereby obtaining a concentrated conductive adhesive.

[0083] An electrode plate, and its preparation method: the same as Example 1.

[0084] A battery, and its preparation method: the same as embodiment 1.

[0085] Example 3

[0086] A conductive adhesive, the preparation method of which comprises the following steps:

[0087] Step 1, oxidation modification:

[0088] Step 1-1, take 30.93g APS (ammonium persulfate), add 1000g deionized water, and prepare an APS aqueous solution with a mass concentration of 3%;

[0089] Step 1-2, adding 5 g of single-walled carbon nanotubes into an APS aqueous solution with a mass concentration of 3%, and ultrasonically treating the solution for 2 h using an ultrasonic cleaning machine to obtain a first mixed solution;

[0090] Step 1-3, stirring the first mixed solution at 40° C. and 100 rpm for 6 hours to obtain a first modified carbon nanotube aqueous dispersion;

[0091] Step 1-4, filtering the first modified carbon nanotube aqueous dispersion, washing the filter cake with deionized water until it is neutral, to obtain modified carbon nanotubes;

[0092] Step 2: Dispersion of carbon nanotubes:

[0093] Step 2-1, placing the modified carbon nanotubes prepared in step 1 in 5 kg of deionized water at a ratio of carbon nanotubes to deionized water of 1:1000 by weight, and breaking them up with a disperser to prepare a second mixed solution;

[0094] Step 2-2, the second mixed solution was subjected to ultrasonic treatment at 20 Hz for 4 h using a cell disruptor, and then filtered through a 150-200 mesh filter to obtain a second modified carbon nanotube aqueous dispersion. The solid content of the obtained second modified carbon nanotube aqueous dispersion was determined to be 0.342‰;

[0095] Step 3, blending: in parts by weight, according to the ratio of carbon nanotubes to the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid of 1:18, take 460g of the second modified carbon nanotube aqueous dispersion with a solid content of 0.342‰ prepared in step 2, stir at a speed of 1000rpm, then add 47.20g of binder polymer (the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 6%) to the stirred second modified carbon nanotube aqueous dispersion, continue stirring at a speed of 1000rpm for 60min, until it is evenly dispersed, to prepare a conductive adhesive, and it is calculated that the solid content of the conductive adhesive is 0.59%;

[0096] The prepared conductive adhesive is concentrated during the pulping and electrode preparation process to increase its solid content for easy application. Therefore, it also includes:

[0097] Step 4, concentration: The conductive adhesive with a solid content of 0.59% obtained in step 3 is concentrated by rotary evaporation at 70 degrees Celsius to a solid content of 4.5% to obtain a conductive adhesive.

[0098] An electrode plate, and its preparation method: the same as Example 1.

[0099] A battery, and its preparation method: the same as embodiment 1.

[0100] Example 4

[0101] A conductive adhesive, the preparation method of which comprises the following steps:

[0102] Step 1, oxidation modification:

[0103] Step 1-1, take 30.93g of hydrogen peroxide, add 1000g of deionized water, and prepare a hydrogen peroxide aqueous solution with a mass concentration of 3%;

[0104] Step 1-2, adding 5 g of single-walled carbon nanotubes to a 3% mass concentration of hydrogen peroxide aqueous solution, and ultrasonically treating the solution for 2 h using an ultrasonic cleaning machine to obtain a first mixed solution;

[0105] Step 1-3, stirring the first mixed solution at 40° C. and 100 rpm for 6 hours to obtain a first modified carbon nanotube aqueous dispersion;

[0106] Step 1-4, filtering the first modified carbon nanotube aqueous dispersion, washing the filter cake with deionized water until it is neutral, to obtain modified carbon nanotubes;

[0107] Step 2: Dispersion of carbon nanotubes:

[0108] Step 2-1, placing the modified carbon nanotubes prepared in step 1 in 5 kg of deionized water at a ratio of carbon nanotubes to deionized water of 1:1000 by weight, and breaking them up with a disperser to prepare a second mixed solution;

[0109] Step 2-2, the second mixed solution was subjected to ultrasonic treatment at 20 Hz for 4 h using a cell disruptor, and then filtered through a 150-200 mesh filter to obtain a second modified carbon nanotube aqueous dispersion. The solid content of the obtained second modified carbon nanotube aqueous dispersion was determined to be 0.342‰;

[0110] Step 3, blending: in parts by weight, according to the ratio of carbon nanotubes to the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid of 1:18, take 460g of the second modified carbon nanotube aqueous dispersion with a solid content of 0.342‰ prepared in step 2, stir at a speed of 1000rpm, then add 47.20g of binder polymer (the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 6%) to the stirred second modified carbon nanotube aqueous dispersion, continue stirring at a speed of 1000rpm for 60min, until it is evenly dispersed, to prepare a conductive adhesive, and it is calculated that the solid content of the conductive adhesive is 0.59%;

[0111] The prepared conductive adhesive is concentrated during the pulping and electrode preparation process to increase its solid content for easy application. Therefore, it also includes:

[0112] Step 4, concentration: The conductive adhesive with a solid content of 0.59% obtained in step 3 is concentrated by rotary evaporation at 70 degrees Celsius to a solid content of 4.5%, thereby obtaining a concentrated conductive adhesive.

[0113] An electrode plate, and its preparation method: the same as Example 1.

[0114] A battery, and its preparation method: the same as embodiment 1.

[0115] Example 5

[0116] A conductive adhesive, the preparation method of which comprises the following steps:

[0117] Step 1, oxidation modification:

[0118] Step 1-1, take 30.93g of potassium permanganate, add 1000g of deionized water, and prepare a potassium permanganate aqueous solution with a mass concentration of 3%;

[0119] Step 1-2, adding 5 g of single-walled carbon nanotubes to a 3% potassium permanganate aqueous solution, and ultrasonically treating the solution for 2 h using an ultrasonic cleaning machine to obtain a first mixed solution;

[0120] Step 1-3, stirring the first mixed solution at 40° C. and 100 rpm for 6 hours to obtain a first modified carbon nanotube aqueous dispersion;

[0121] Step 1-4, filtering the first modified carbon nanotube aqueous dispersion, washing the filter cake with deionized water until it is neutral, to obtain modified carbon nanotubes;

[0122] Step 2: Dispersion of carbon nanotubes:

[0123] Step 2-1, placing the modified carbon nanotubes prepared in step 1 in 5 kg of deionized water at a ratio of carbon nanotubes to deionized water of 1:1000 by weight, and breaking them up with a disperser to prepare a second mixed solution;

[0124] Step 2-2, the second mixed solution was subjected to ultrasonic treatment at 20 Hz for 4 h using a cell disruptor, and then filtered through a 150-200 mesh filter to obtain a second modified carbon nanotube aqueous dispersion. The solid content of the obtained second modified carbon nanotube aqueous dispersion was determined to be 0.342‰;

[0125] Step 3, blending: in parts by weight, according to the mass ratio of carbon nanotubes to the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid being 1:18, 460g of the second modified carbon nanotube aqueous dispersion with a solid content of 0.342‰ prepared in step 2 is taken, and stirred at a speed of 1000rpm, and then 47.20g of a binder polymer (the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 6%) is added to the stirred second modified carbon nanotube aqueous dispersion, and stirring is continued at a speed of 1000rpm for 60min until the dispersion is uniform to prepare a conductive adhesive. It is calculated that the solid content of the conductive adhesive is 0.59%;

[0126] The prepared conductive adhesive is concentrated during the pulping and electrode preparation process to increase its solid content for easy application. Therefore, it also includes:

[0127] Step 4, concentration: The conductive adhesive with a solid content of 0.59% obtained in step 3 is concentrated by rotary evaporation at 70 degrees Celsius to a solid content of 4.5%, thereby obtaining a concentrated conductive adhesive.

[0128] An electrode plate, and its preparation method: the same as Example 1.

[0129] A battery, and its preparation method: the same as embodiment 1.

[0130] Example 6

[0131] A conductive adhesive, the preparation method of which comprises the following steps:

[0132] Step 1, oxidation modification:

[0133] Step 1-1, take 30.93g of sodium peroxide, add 1000g of deionized water, and prepare a sodium peroxide aqueous solution with a mass concentration of 3%;

[0134] Step 1-2, adding 5 g of single-walled carbon nanotubes into a sodium peroxide aqueous solution with a mass concentration of 3%, and ultrasonically treating the solution for 2 h using an ultrasonic cleaning machine to obtain a first mixed solution;

[0135] Step 1-3, stirring the first mixed solution at 40° C. and 100 rpm for 6 hours to obtain a first modified carbon nanotube aqueous dispersion;

[0136] Step 1-4, filtering the first modified carbon nanotube aqueous dispersion, washing the filter cake with deionized water until it is neutral, to obtain modified carbon nanotubes;

[0137] Step 2: Dispersion of carbon nanotubes:

[0138] Step 2-1, placing the modified carbon nanotubes prepared in step 1 in 5 kg of deionized water at a ratio of carbon nanotubes to deionized water of 1:1000 by weight, and breaking them up with a disperser to prepare a second mixed solution;

[0139] Step 2-2, the second mixed solution was subjected to ultrasonic treatment at 20 Hz for 4 h using a cell disruptor, and then filtered through a 150-200 mesh filter to obtain a second modified carbon nanotube aqueous dispersion. The solid content of the obtained second modified carbon nanotube aqueous dispersion was determined to be 0.342‰;

[0140] Step 3, blending: according to the mass ratio of carbon nanotubes to the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid of 1:18, take 460g of the second modified carbon nanotube aqueous dispersion with a solid content of 0.342‰ prepared in step 2, stir at a speed of 1000rpm, then add 47.20g of binder polymer (the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 6%) to the stirred second modified carbon nanotube aqueous dispersion, continue to stir at a speed of 1000rpm for 60min, until it is evenly dispersed, to prepare a conductive adhesive, and the solid content of the conductive adhesive is calculated to be 0.59%;

[0141] The prepared conductive adhesive is concentrated during the pulping and electrode preparation process to increase its solid content for easy application. Therefore, it also includes:

[0142] Step 4, concentration: The conductive adhesive with a solid content of 0.59% obtained in step 3 is concentrated by rotary evaporation at 70 degrees Celsius to a solid content of 4.5%, thereby obtaining a concentrated conductive adhesive.

[0143] An electrode plate, and its preparation method: the same as Example 1.

[0144] A battery, and its preparation method: the same as embodiment 1.

[0145] Example 7

[0146] A conductive adhesive, the preparation method of which comprises the following steps:

[0147] Step 1, oxidation modification:

[0148] Step 1-1, taking 30.93 g of potassium persulfate, adding 1000 g of deionized water to prepare a potassium persulfate aqueous solution with a mass concentration of 3%;

[0149] Step 1-2, adding 5 g of single-walled carbon nanotubes into a 3% potassium persulfate aqueous solution, and ultrasonically treating the solution for 2 h using an ultrasonic cleaning machine to obtain a first mixed solution;

[0150] Step 1-3, stirring the first mixed solution at 40° C. and 100 rpm for 6 hours to obtain a first modified carbon nanotube aqueous dispersion;

[0151] Step 1-4, filtering the first modified carbon nanotube aqueous dispersion, washing the filter cake with deionized water until it is neutral, to obtain modified carbon nanotubes;

[0152] Step 2: Dispersion of carbon nanotubes:

[0153] Step 2-1, placing the modified carbon nanotubes prepared in step 1 in 5 kg of deionized water at a ratio of carbon nanotubes to deionized water of 1:1000 by weight, and breaking them up with a disperser to prepare a second mixed solution;

[0154] Step 2-2, the second mixed solution was subjected to ultrasonic treatment at 20 Hz for 4 h using a cell disruptor, and then filtered through a 150-200 mesh filter to obtain a second modified carbon nanotube aqueous dispersion. The solid content of the obtained second modified carbon nanotube aqueous dispersion was determined to be 0.342‰;

[0155] Step 3, blending: in parts by weight, according to the mass ratio of carbon nanotubes to the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid being 1:18, 460g of the second modified carbon nanotube aqueous dispersion with a solid content of 0.342‰ prepared in step 2 is taken, and stirred at a speed of 1000rpm, and then 47.20g of a binder polymer (the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 6%) is added to the stirred second modified carbon nanotube aqueous dispersion, and stirring is continued at a speed of 1000rpm for 60min until the dispersion is uniform to prepare a conductive adhesive. It is calculated that the solid content of the conductive adhesive is 0.59%;

[0156] The prepared conductive adhesive is concentrated during the pulping and electrode preparation process to increase its solid content for easy application. Therefore, it also includes:

[0157] Step 4, concentration: The conductive adhesive with a solid content of 0.59% obtained in step 3 is concentrated by rotary evaporation at 70 degrees Celsius to a solid content of 4.5%, thereby obtaining a concentrated conductive adhesive.

[0158] An electrode plate, and its preparation method: the same as Example 1.

[0159] A battery, and its preparation method: the same as embodiment 1.

[0160] Example 8

[0161] A conductive adhesive, the preparation method of which comprises the following steps:

[0162] Step 1, oxidation modification:

[0163] Step 1-1, take 30.93g of oxidant APS (ammonium persulfate), add 1000g of deionized water, and prepare an oxidant aqueous solution with a mass concentration of 3%;

[0164] Step 1-2, adding 5 g of single-walled carbon nanotubes to an aqueous solution of an oxidant having a mass concentration of 3%, and ultrasonically treating the solution for 2 h using an ultrasonic cleaning machine to obtain a first mixed solution;

[0165] Step 1-3, stirring the first mixed solution at 40° C. and 100 rpm for 6 hours to obtain a first modified carbon nanotube aqueous dispersion;

[0166] Step 1-4, filtering the first modified carbon nanotube aqueous dispersion, washing the filter cake with deionized water until it is neutral, to obtain second modified carbon nanotubes;

[0167] Step 2: Dispersion of carbon nanotubes:

[0168] Step 2-1, placing the modified carbon nanotubes prepared in step 1 in 5 kg of deionized water at a ratio of carbon nanotubes to deionized water of 1:1000 by weight, and breaking them up with a disperser to prepare a second mixed solution;

[0169] Step 2-2, the second mixed solution was subjected to ultrasonic treatment at 20 Hz for 4 h using a cell disruptor, and then filtered through a 150-200 mesh filter to obtain a second modified carbon nanotube aqueous dispersion. The solid content of the obtained second modified carbon nanotube aqueous dispersion was determined to be 0.342‰;

[0170] Step 3, blending: in parts by weight, according to the ratio of carbon nanotubes to the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid of 1:18, take 460g of the second modified carbon nanotube aqueous dispersion with a solid content of 0.342‰ prepared in step 2, stir at a speed of 1000rpm, then add 47.20g of binder polymer (the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 6%) into the stirred second modified carbon nanotube aqueous dispersion, continue stirring at a speed of 1000rpm for 60min, until it is evenly dispersed, to prepare a conductive adhesive, and it is calculated that the solid content of the conductive adhesive is 0.59%.

[0171] Example 9

[0172] A conductive adhesive, the preparation method of which comprises the following steps:

[0173] Step 1, oxidation modification:

[0174] Step 1-1, take 0.05g of ammonium persulfate and 0.05g of hydrogen peroxide, add 999.9g of deionized water, and prepare an oxidant aqueous solution with a mass concentration of 0.01%;

[0175] Step 1-2, adding 5 g of single-walled carbon nanotubes to 1000 g of an oxidant aqueous solution with a mass concentration of 0.01%, and ultrasonically treating the solution for 1 h using an ultrasonic cleaning machine to obtain a first mixed solution;

[0176] Step 1-3, stirring the first mixed solution at 60° C. and 100 rpm for 48 hours to obtain a first modified carbon nanotube aqueous dispersion;

[0177] Step 1-4, filtering the first modified carbon nanotube aqueous dispersion, washing the filter cake with deionized water until it is neutral, to obtain modified carbon nanotubes;

[0178] Step 2: Dispersion of carbon nanotubes:

[0179] Step 2-1, placing the modified carbon nanotubes prepared in step 1 in 2.5 kg of deionized water at a ratio of carbon nanotubes to deionized water of 1:500 by weight, and breaking them up with a disperser to prepare a second mixed solution;

[0180] Step 2-2, the second mixed solution was subjected to ultrasonic treatment at 10 Hz for 4 h using a cell disruptor, and then filtered through a 150-200 mesh filter to obtain a second modified carbon nanotube aqueous dispersion. The solid content of the obtained second modified carbon nanotube aqueous dispersion was determined to be 0.342‰;

[0181] Step 3, blending: by weight, the ratio of carbon nanotubes to the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 1:18, 460g of the second modified carbon nanotube aqueous dispersion with a solid content of 0.342‰ prepared in step 2 is taken, stirred at a speed of 1000rpm, and then 47.20g of a binder polymer (the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 6%) is added to the stirred second modified carbon nanotube aqueous dispersion, and stirring is continued at a speed of 1000rpm for 60min until the dispersion is uniform, to obtain a conductive adhesive, and the solid content of the conductive adhesive is calculated to be 0.59%;

[0182] The prepared conductive adhesive is concentrated during the pulping and electrode preparation process to increase its solid content for easy application. Therefore, it also includes:

[0183] Step 4, concentration: The conductive adhesive with a solid content of 0.59% obtained in step 3 is concentrated by rotary evaporation at 70 degrees Celsius to a solid content of 4.5%, thereby obtaining a concentrated conductive adhesive.

[0184] An electrode plate, and its preparation method: the same as Example 1.

[0185] A battery, and its preparation method: the same as embodiment 1.

[0186] Example 10

[0187] A conductive adhesive, the preparation method of which comprises the following steps:

[0188] Step 1, oxidation modification:

[0189] Step 1-1, take 0.5g potassium persulfate and 0.5g hydrogen peroxide, add 999g deionized water, and prepare an oxidant aqueous solution with a mass concentration of 0.1%;

[0190] Step 1-2, adding 5 g of multi-walled carbon nanotubes to 1000 g of an aqueous solution of an oxidant having a mass concentration of 0.1%, and ultrasonically treating the solution for 3 h using an ultrasonic cleaning machine to obtain a first mixed solution;

[0191] Step 1-3, stirring the first mixed solution at 80° C. and 100 rpm for 36 hours to obtain a first modified carbon nanotube aqueous dispersion;

[0192] Step 1-4, filtering the first modified carbon nanotube aqueous dispersion, washing the filter cake with deionized water until it is neutral, to obtain modified carbon nanotubes;

[0193] Step 2: Dispersion of carbon nanotubes:

[0194] Step 2-1, placing the modified carbon nanotubes prepared in step 1 in 10 kg of deionized water at a ratio of carbon nanotubes to deionized water of 1:2000 by weight, and breaking them up with a disperser to prepare a second mixed solution;

[0195] Step 2-2, the second mixed solution was subjected to ultrasonic treatment at 30 Hz for 4 h using a cell disruptor, and then filtered through a 150-200 mesh filter to obtain a second modified carbon nanotube aqueous dispersion. The solid content of the obtained second modified carbon nanotube aqueous dispersion was determined to be 0.342‰;

[0196] Step 3, blending: by weight, the ratio of carbon nanotubes to the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 1:12, 460g of the second modified carbon nanotube aqueous dispersion with a solid content of 0.342‰ prepared in step 2 is taken, stirred at a speed of 1000rpm, and then 31.46g of a binder polymer (the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 6%) is added to the stirred second modified carbon nanotube aqueous dispersion, and stirring is continued at a speed of 1000rpm for 60min until the dispersion is uniform, to obtain a conductive adhesive, and the solid content of the conductive adhesive is calculated to be 0.42%;

[0197] The prepared conductive adhesive is concentrated during the pulping and electrode preparation process to increase its solid content for easy application. Therefore, it also includes:

[0198] Step 4, concentration: The conductive adhesive with a solid content of 0.42% obtained in step 3 is concentrated by rotary evaporation at 70 degrees Celsius to a solid content of 4.5%, thereby obtaining a concentrated conductive adhesive.

[0199] An electrode plate, and its preparation method: the same as Example 1.

[0200] A battery, and its preparation method: the same as embodiment 1.

[0201] Embodiment 11

[0202] A conductive adhesive, the preparation method of which comprises the following steps:

[0203] Step 1, oxidation modification:

[0204] Step 1-1, take 1.0g of potassium persulfate and 1.0g of potassium permanganate, add 998g of deionized water, and prepare an oxidant aqueous solution with a mass concentration of 0.2%;

[0205] Step 1-2, adding 5 g of multi-walled carbon nanotubes to 1000 g of an oxidant aqueous solution with a mass concentration of 0.2%, and ultrasonically treating the solution for 3 h using an ultrasonic cleaning machine to obtain a first mixed solution;

[0206] Step 1-3, stirring the first mixed solution at 20° C. and 100 rpm for 24 hours to obtain a first modified carbon nanotube aqueous dispersion;

[0207] Step 1-4, filtering the first modified carbon nanotube aqueous dispersion, washing the filter cake with deionized water until it is neutral, to obtain modified carbon nanotubes;

[0208] Step 2: Dispersion of carbon nanotubes:

[0209] Step 2-1, placing the modified carbon nanotubes prepared in step 1 in 20 kg of deionized water at a ratio of carbon nanotubes to deionized water of 1:4000 by weight, and breaking them up with a disperser to prepare a second mixed solution;

[0210] Step 2-2, subjecting the second mixed solution to ultrasonic treatment at 40 Hz for 4 h using a cell disruptor, and then filtering through a 150-200 mesh filter to obtain a second modified carbon nanotube aqueous dispersion. The solid content of the obtained second modified carbon nanotube aqueous dispersion was determined to be 0.342‰;

[0211] Step 3, blending: by weight, the ratio of carbon nanotubes to the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 1:10, 460g of the second modified carbon nanotube aqueous dispersion with a solid content of 0.342‰ prepared in step 2 is taken, stirred at a speed of 1000rpm, and then 26.22g of a binder polymer (the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 6%) is added to the stirred second modified carbon nanotube aqueous dispersion, and stirring is continued at a speed of 1000rpm for 60min until the dispersion is uniform, to obtain a conductive adhesive, and the solid content of the conductive adhesive is calculated to be 0.36%;

[0212] The prepared conductive adhesive is concentrated during the pulping and electrode preparation process to increase its solid content for easy application. Therefore, it also includes:

[0213] Step 4, concentration: The conductive adhesive with a solid content of 0.36% obtained in step 3 is concentrated by rotary evaporation at 70 degrees Celsius to a solid content of 4.5%, thereby obtaining a concentrated conductive adhesive.

[0214] An electrode plate, and its preparation method: the same as Example 1.

[0215] A battery, and its preparation method: the same as embodiment 1.

[0216] Example 12

[0217] A conductive adhesive, the preparation method of which comprises the following steps:

[0218] Step 1, oxidation modification:

[0219] Step 1-1, take 2.5g of ammonium persulfate and 2.5g of potassium permanganate, add 995g of deionized water, and prepare an oxidant aqueous solution with a mass concentration of 0.5%;

[0220] Step 1-2, adding 5 g of multi-walled carbon nanotubes to 1000 g of an oxidant aqueous solution with a mass concentration of 0.5%, and ultrasonically treating the solution for 5 h using an ultrasonic cleaning machine to obtain a first mixed solution;

[0221] Step 1-3, stirring the first mixed solution at 20° C. and 100 rpm for 2 hours to obtain a first modified carbon nanotube aqueous dispersion;

[0222] Step 1-4, filtering the first modified carbon nanotube aqueous dispersion, washing the filter cake with deionized water until it is neutral, to obtain modified carbon nanotubes;

[0223] Step 2: Dispersion of carbon nanotubes:

[0224] Step 2-1, placing the modified carbon nanotubes prepared in step 1 in 25 kg of deionized water at a ratio of carbon nanotubes to deionized water of 1:5000 by weight, and breaking them up with a disperser to prepare a second mixed solution;

[0225] Step 2-2, the second mixed solution was subjected to ultrasonic treatment at 50 Hz for 4 h using a cell disruptor, and then filtered through a 150-200 mesh filter to obtain a second modified carbon nanotube aqueous dispersion. The solid content of the obtained second modified carbon nanotube aqueous dispersion was determined to be 0.342‰;

[0226] Step 3, blending: by weight, the ratio of carbon nanotubes to the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 1:50, 460g of the second modified carbon nanotube aqueous dispersion with a solid content of 0.342‰ prepared in step 2 is taken, and stirred at a speed of 1000rpm, and then 131.1g of a binder polymer (the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 6%) is added to the stirred second modified carbon nanotube aqueous dispersion, and stirring is continued at a speed of 1000rpm for 60min until the dispersion is uniform, to obtain a conductive adhesive, and the solid content of the conductive adhesive is calculated to be 1.36%;

[0227] The prepared conductive adhesive is concentrated during the pulping and electrode preparation process to increase its solid content for easy application. Therefore, it also includes:

[0228] Step 4, concentration: The conductive adhesive with a solid content of 1.36% obtained in step 3 is concentrated by rotary evaporation at 70 degrees Celsius to a solid content of 4.5%, thereby obtaining a concentrated conductive adhesive.

[0229] An electrode plate, and its preparation method: the same as Example 1.

[0230] A battery, and its preparation method: the same as embodiment 1.

[0231] Embodiment 13

[0232] A conductive adhesive, the preparation method of which comprises the following steps:

[0233] Step 1, oxidation modification:

[0234] Step 1-1, take 30.93g of oxidant APS (ammonium persulfate), add 1000g of deionized water, and prepare an oxidant aqueous solution with a mass concentration of 3%;

[0235] Step 1-2, adding 5 g of single-walled carbon nanotubes to an aqueous solution of an oxidant having a mass concentration of 3%, and ultrasonically treating the solution for 2 h using an ultrasonic cleaning machine to obtain a first mixed solution;

[0236] Step 1-3, stirring the first mixed solution at 40° C. and 100 rpm for 6 hours to obtain a first modified carbon nanotube aqueous dispersion;

[0237] Step 1-4, filtering the first modified carbon nanotube aqueous dispersion, washing the filter cake with deionized water until it is neutral, to obtain modified carbon nanotubes;

[0238] Step 2: Dispersion of carbon nanotubes:

[0239] Step 2-1, placing the modified carbon nanotubes prepared in step 1 in 5 kg of deionized water at a ratio of carbon nanotubes to deionized water of 1:1000 by weight, and breaking them up with a disperser to prepare a second mixed solution;

[0240] Step 2-2, the second mixed solution was subjected to ultrasonic treatment at 20 Hz for 4 h using a cell disruptor, and then filtered through a 150-200 mesh filter to obtain a second modified carbon nanotube aqueous dispersion. The solid content of the obtained second modified carbon nanotube aqueous dispersion was determined to be 0.342‰;

[0241] Step 3, blending: by weight, the ratio of carbon nanotubes to the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 1:9, 460g of the second modified carbon nanotube aqueous dispersion with a solid content of 0.342‰ prepared in step 2 is taken, and stirred at a speed of 1000rpm, and then 23.60g of a binder polymer (the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 6%) is added to the stirred second modified carbon nanotube aqueous dispersion, and stirring is continued at a speed of 1000rpm for 60min until it is evenly dispersed to obtain a conductive adhesive. It is calculated that the solid content of the conductive adhesive is 0.33%;

[0242] The prepared conductive adhesive is concentrated during the pulping and electrode preparation process to increase its solid content for easy application. Therefore, it also includes:

[0243] Step 4, concentration: The conductive adhesive with a solid content of 0.33% obtained in step 3 is concentrated by rotary evaporation at 70 degrees Celsius to a solid content of 4.5%, thereby obtaining a concentrated conductive adhesive.

[0244] An electrode plate, and its preparation method: the same as Example 1.

[0245] A battery, and its preparation method: the same as embodiment 1.

[0246] Embodiment 14

[0247] A conductive adhesive, the preparation method of which comprises the following steps:

[0248] Step 1, oxidation modification:

[0249] Step 1-1, take 30.93g of oxidant APS (ammonium persulfate), add 1000g of deionized water, and prepare an oxidant aqueous solution with a mass concentration of 3%;

[0250] Step 1-2, adding 5 g of single-walled carbon nanotubes to an aqueous solution of an oxidant having a mass concentration of 3%, and ultrasonically treating the solution for 2 h using an ultrasonic cleaning machine to obtain a first mixed solution;

[0251] Step 1-3, stirring the first mixed solution at 40° C. and 100 rpm for 6 hours to obtain a first modified carbon nanotube aqueous dispersion;

[0252] Step 1-4, filtering the first modified carbon nanotube aqueous dispersion, washing the filter cake with deionized water until it is neutral, to obtain modified carbon nanotubes;

[0253] Step 2: Dispersion of carbon nanotubes:

[0254] Step 2-1, placing the modified carbon nanotubes prepared in step 1 in 5 kg of deionized water at a ratio of carbon nanotubes to deionized water of 1:1000 by weight, and breaking them up with a disperser to prepare a second mixed solution;

[0255] Step 2-2, the second mixed solution was subjected to ultrasonic treatment at 20 Hz for 4 h using a cell disruptor, and then filtered through a 150-200 mesh filter to obtain a second modified carbon nanotube aqueous dispersion. The solid content of the obtained second modified carbon nanotube aqueous dispersion was determined to be 0.342‰;

[0256] Step 3, blending: by weight, the ratio of carbon nanotubes to the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 1:55, 460g of the second modified carbon nanotube aqueous dispersion with a solid content of 0.342‰ prepared in step 2 is taken, stirred at a speed of 1000rpm, and then 144.21g of a binder polymer (the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 6%) is added to the stirred second modified carbon nanotube aqueous dispersion, and stirring is continued at a speed of 1000rpm for 60min until it is evenly dispersed to obtain a conductive adhesive. It is calculated that the solid content of the conductive adhesive is 1.46%;

[0257] The prepared conductive adhesive is concentrated during the pulping and electrode preparation process to increase its solid content for easy application. Therefore, it also includes:

[0258] Step 4, concentration: The conductive adhesive with a solid content of 1.46% obtained in step 3 is concentrated by rotary evaporation at 70 degrees Celsius to a solid content of 4.5%, thereby obtaining a concentrated conductive adhesive.

[0259] An electrode plate, and its preparation method: the same as Example 1.

[0260] A battery, and its preparation method: the same as embodiment 1.

[0261] Comparative Example 1

[0262] An electrode plate, the preparation method of which comprises the following steps:

[0263] Step a, after mixing a Si-C composite material containing Si and C (a silicon-based material with a gram capacity of 600 mAh / g), conductive graphite, CMC, a carbon tube conductive paste (commercially available, OCSiAl TUBALL, with a solid content of 0.4%), and a binder polymer (a terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid with a solid content of 6%), deionized water is added, and after being evenly dispersed, the mixture is passed through a 100-mesh sieve to obtain an electrode paste with a total solid content of 42%; in the electrode paste, the electrode material accounts for 96.05wt% of the total solid content, the conductive graphite (SP) accounts for 0.95wt% of the total solid content, the CMC accounts for 0.5wt% of the total solid content, the carbon tube conductive paste accounts for 0.05wt%, and the binder polymer accounts for 2.5wt%;

[0264] Step b: coat the electrode slurry on a 10 μm thick copper foil as a current collector, and then dry it at 120°C for 5 minutes. After cooling naturally to room temperature in the furnace, 4 The electrode sheet is obtained by rolling with a unit length load of N / m.

[0265] A battery, the preparation method of which is as follows:

[0266] The electrode plate is used as the negative electrode, nickel cobalt manganese oxide NCM523 is used as the positive electrode, ethylene carbonate EC: ethyl methyl carbonate EMC: diethyl carbonate DEC mixed solvent in a mass ratio of 3:2:5 containing 1M LiPF6 is used as the electrolyte, and a PE / PP diaphragm is used as the diaphragm to manufacture a P383450 lithium-ion battery.

[0267] Comparative Example 2

[0268] A conductive adhesive, the preparation method of which comprises the following steps:

[0269] Step 1, oxidation modification:

[0270] Step 1-1, take 50.03g of oxidant APS (ammonium persulfate), add 1000g of deionized water, and prepare an oxidant aqueous solution with a mass concentration of 4.76%;

[0271] Step 1-2, adding 5 g of single-walled carbon nanotubes to an oxidant aqueous solution with a mass concentration of 4.76%, and ultrasonically treating the solution for 2 h using an ultrasonic cleaning machine to obtain a first mixed solution;

[0272] Step 1-3, stirring the first mixed solution at 40° C. and 100 rpm for 6 hours to obtain a first modified carbon nanotube aqueous dispersion;

[0273] Step 1-4, filtering the first modified carbon nanotube aqueous dispersion, washing the filter cake with deionized water until it is neutral, to obtain modified carbon nanotubes;

[0274] Step 2: Dispersion of carbon nanotubes:

[0275] Step 2-1, placing the modified carbon nanotubes prepared in step 1 in 5 kg of deionized water at a ratio of carbon nanotubes to deionized water of 1:1000 by weight, and breaking them up with a disperser to prepare a second mixed solution;

[0276] Step 2-2, the second mixed solution was subjected to ultrasonic treatment at 20 Hz for 4 h using a cell disruptor, and then filtered through a 150-200 mesh filter to obtain a second modified carbon nanotube aqueous dispersion. The solid content of the obtained modified carbon nanotube aqueous dispersion was determined to be 0.763‰;

[0277] Step 3, blending: in parts by weight, according to the ratio of carbon nanotubes to the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid of 1:25, take 305.5g of the second modified carbon nanotube aqueous dispersion with a solid content of 0.763‰ prepared in step 2, stir at a speed of 1000rpm, then add 97.12g of binder polymer (the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 6%) to the stirred second modified carbon nanotube aqueous dispersion, continue stirring at a speed of 1000rpm for 30min, until it is evenly dispersed, to prepare a conductive adhesive, and it is calculated that the solid content of the conductive adhesive is 1.51%;

[0278] The prepared conductive adhesive is concentrated during the pulping and electrode preparation process to increase its solid content for easy application. Therefore, it also includes:

[0279] Step 4, concentration: The mixture dispersion with a solid content of 1.51% obtained in step 3 is concentrated by rotary evaporation at 70 degrees Celsius to a solid content of 4.5% to obtain a conductive adhesive.

[0280] An electrode plate, and its preparation method: the same as Example 1.

[0281] A battery, and its preparation method: the same as embodiment 1.

[0282] Comparative Example 3 (using other types of carbon nanotubes instead of the oxidized carbon nanotubes in Example 2)

[0283] A binder for lithium battery silicon negative electrode, the preparation method of which comprises the following steps:

[0284] Step 1: Dispersion of carbon nanotubes:

[0285] Step 1-1, placing 1.7 g of modified single-walled carbon nanotubes (high-purity carboxylated single-walled carbon nanotubes (short), length 1-3 μm, Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.) in 5 kg of deionized water, and breaking it up with a disperser to prepare a second mixed solution;

[0286] Step 1-2, the second mixed solution was subjected to ultrasonic treatment at 20 Hz for 4 h using a cell disruptor, and then filtered through a 150-200 mesh filter to obtain a modified carbon nanotube aqueous dispersion. The solid content of the obtained modified carbon nanotube aqueous dispersion was determined to be 0.342‰;

[0287] Step 2, blending: in parts by weight, according to the ratio of carbon nanotubes to the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid of 1:25, take 303.6g of the modified carbon nanotube aqueous dispersion with a solid content of 0.34‰ prepared in step 1, stir at a speed of 1000rpm, then add 43.01g of binder polymer (the solid content of the terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid is 6%) to the modified carbon nanotube aqueous dispersion in a stirring state, continue to stir at a speed of 1000rpm for 60min, until it is evenly dispersed, to prepare a conductive adhesive, and it is calculated that the solid content of the conductive adhesive is 0.77%;

[0288] The prepared conductive adhesive is concentrated during the pulping and electrode preparation process to increase its solid content for easy application. Therefore, it also includes:

[0289] Step 3, concentration: The mixture dispersion with a solid content of 0.77% obtained in step 3 is concentrated by rotary evaporation at 70 degrees Celsius to a solid content of 4.5%, thereby obtaining a concentrated conductive adhesive.

[0290] An electrode plate, and its preparation method: the same as Example 1.

[0291] A battery, and its preparation method: the same as embodiment 1.

[0292] Effect example 1:

[0293] The electrode plates of Example 2 and Comparative Example 1 were scanned by SEM morphology respectively;

[0294] The peel strength and film resistivity of the electrode sheets prepared in each embodiment and each comparative example are measured respectively;

[0295] The electrochemical properties of the batteries prepared in the examples and comparative examples were measured respectively.

[0296] Method for measuring peel strength: Cut the electrode sheets of each embodiment and comparative example into strips of 20 cm × 2.5 cm, adhere a 1 mm thick steel plate on the collector side with double-sided tape, stick a transparent tape on the coating layer side, peel in a 180° direction at a speed of 100 mm / min using a tensile testing machine, and measure the peel stress. The test results are shown in Table 1.

[0297] Diaphragm resistivity test: set the pressure to 0.5Mpa, test see Table 1 and Figure 3 as shown in .

[0298] SEM morphology scanning of the electrode: The electrode sheets prepared in Example 2 and Comparative Example 1 were subjected to SEM morphology scanning. Figure 1-2 ;

[0299] EIS test: The batteries prepared in the examples and comparative examples were charged and discharged at 25°C, 2.5-4.2V, and 0.5C to test their EIS performance. Figure 3 .

[0300] Table 1

[0301]

[0302]

[0303] From the data in Table 1, it can be concluded that: since the electrode peeling strength of Examples 1-3 is greater than that of Comparative Examples 1-3; the membrane resistivity of the electrode of Examples 1-3 is less than that of Comparative Examples 1-3, it can be concluded that: the dispersion effect of carbon nanotubes in Examples 1-3 of the present invention is better than that of Comparative Examples 1-3, when the single-walled carbon nanotubes can maintain a good length and achieve good coating of the electrode active material, it can provide better mechanical properties for the electrode electrode. At the same time, it can provide a better electronic conduction network inside the electrode to reduce the internal resistance of the electrode membrane.

[0304] from Figure 1-2 From the data we can see: Figure 1 The carbon nanotubes are well dispersed in the electrode and are relatively long (shown in the figure as >4μm); Figure 2 In the traditional electrode preparation method using carbon nanotubes as conductive paste, carbon nanotubes agglomerate significantly.

[0305] from Figure 3It can be seen from the data in: in the process of electrode preparation, the use of the conductive binder of the present invention to prepare the electrode pole piece is compared with the traditional electrode pole piece preparation method of directly adding carbon tube conductive slurry in comparative example 1. The present invention can obtain lower ion transfer impedance; this is mainly because the method of the present invention ensures that the original morphology of the single-walled carbon tube is not destroyed, and the carbon nanotubes are better dispersed in the electrode system. The conductive binder of the present invention helps to construct and optimize the three-dimensional void structure of the electrode while achieving good coating of the electrode active material, avoiding the close stacking of active materials caused by traditional processes, thereby constructing ion diffusion and transfer channels. The reduction of ion transfer impedance helps to improve the rate performance of the material.

[0306] Effect Example 2:

[0307] The dispersion levels of the conductive adhesives in each embodiment and comparative examples 2-3 in water were measured, and the results are shown in Table 2.

[0308] Test method: The conductive adhesives of each embodiment and comparative example are prepared into aqueous dispersions of equal concentrations, and then the absorbance thereof is measured. The higher the absorbance, the better the dispersion of the carbon nanotubes at the concentration. The specific test method is as follows:

[0309] 1) Test instruments and tools:

[0310] One-tenth of a balance, UV-1900I

[0311] 2) Prepare tools:

[0312] (1) The instrument was turned on for 30 minutes to preheat, and deionized water was used as a blank.

[0313] (2) Sample preparation Weigh a certain mass of binder, accurately weigh its mass as M0, solid content as S%, add deionized water of mass M1 to dilute, the calculation formula of M1 is: M1 = M0*S*2000 / 7.

[0314] (3) Stir the diluted mixed solution evenly with a dropper (5-10 minutes) until no colloid particles are visible to the naked eye.

[0315] 3) Testing:

[0316] Use a pipette to absorb the dispersed mixed solution, wash the cuvette 3 times, then inject 2 / 3 of the highly diluted solution, and wipe the outside of the cuvette clean with lens paper. Put it into the instrument, let it stand for 30 seconds, set the wavelength to 267nm, read the absorbance value Abs after the value stabilizes, and take the average value of 3 parallel tests.

[0317] Table 2

[0318] Sample name Absorbance (Abs) Sample name Absorbance (Abs) Sample name Absorbance (Abs) Example 1 1.143 Example 2 2.075 Example 3 2.786 Example 4 2.678 Example 5 2.997 Example 6 2.879 Example 7 2.883 Example 8 - Example 9 0.868 Example 10 1.677 Embodiment 11 2.687 Example 12 1.114 Example 13 3.279 Embodiment 14 0.997 Comparative Example 2 1.544 Comparative Example 3 1.978

[0319] From the results in Table 2, it can be seen that the carbon tubes in the binder formed in Comparative Example 2 are agglomerated.

[0320] The above-described embodiments are only preferred embodiments of the present invention, and are not exhaustive of the feasible implementations of the present invention. For those skilled in the art, any obvious changes made thereto without departing from the principles and spirit of the present invention should be considered to be included in the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a conductive adhesive, characterized in that: The steps include: Step 1, preparing modified carbon nanotubes; Step 2, dispersing the modified carbon nanotubes in step 1 in water to obtain a second modified carbon nanotube aqueous dispersion; In parts by weight, the ratio of carbon nanotubes to deionized water is 1:500-5000; Step 3, adding a polymer binder containing an acrylic acid multipolymer to the second modified carbon nanotube aqueous dispersion prepared in step 2, and mechanically mixing to obtain a conductive binder; The acrylic multipolymer in step 3 is a terpolymer of acrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid and methacrylic acid; Step 4: Concentrate the conductive adhesive obtained in step 3 by rotary evaporation to obtain a concentrated conductive adhesive.

2. The method for preparing a conductive adhesive according to claim 1, characterized in that: The preparation of modified carbon nanotubes in step 1 comprises the following steps: The oxidant is dissolved in water to obtain an oxidant aqueous solution; carbon nanotubes are added to the oxidant aqueous solution and ultrasonicated for 1-5 hours to obtain a first mixed solution; the first mixed solution is stirred at 20-80° C. for 2-48 hours to obtain a first modified carbon nanotube aqueous dispersion; then, the first modified carbon nanotube aqueous dispersion is filtered and washed to obtain the modified carbon nanotubes.

3. The method for preparing a conductive adhesive according to claim 2, characterized in that: The mass percentage concentration of the oxidant aqueous solution is 0.01%-0.5%.

4. The method for preparing a conductive adhesive according to claim 2, characterized in that: The carbon nanotubes are added to the oxidant aqueous solution, in parts by weight, the carbon nanotubes are 1 part, and the oxidant aqueous solution is 100-400 parts.

5. The method for preparing a conductive adhesive according to claim 2, characterized in that: The oxidant is one or a mixture of two or more of inorganic persulfate oxide, peroxide, hydrogen peroxide or potassium permanganate.

6. The method for preparing a conductive adhesive according to claim 1, characterized in that: The step of dispersing the modified carbon nanotubes in water in step 2 specifically includes: The modified carbon nanotubes are placed in deionized water to obtain a second mixed solution, and the second mixed solution is ultrasonicated using a cell disruptor to obtain the second modified carbon nanotube aqueous dispersion.

7. The method for preparing a conductive adhesive according to claim 6, characterized in that: The ultrasonic frequency of the cell disruptor is 10-50 Hz.

8. The method for preparing a conductive adhesive according to claim 1, characterized in that: In step 3, an acrylic acid multipolymer is added to the second modified carbon nanotube aqueous dispersion in step 2, and the ratio of carbon nanotubes to the acrylic acid multipolymer is 1:10-50 in parts by weight.

9. The method for preparing a conductive adhesive according to claim 1, characterized in that: The modified carbon nanotubes in step 1 are single-walled carbon nanotubes.

10. A conductive adhesive, characterized in that: The conductive adhesive is prepared by the method for preparing the conductive adhesive as described in any one of claims 1 to 9.

11. An electrode plate, characterized in that: Contains the conductive adhesive as claimed in claim 10.

12. A battery, characterized in that: An electrode plate as claimed in claim 11 is provided.

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