Lithium battery conductive paste and production process thereof

Abstract

The application discloses a kind of lithium battery conductive slurry and its production process, first water-based polymer and deionized water are sheared at low temperature condition at high speed, form uniform stable solution, then add conductive particle, defoaming agent, dispersing agent and thickener, so that each component is uniformly mixed, and lithium battery conductive slurry is prepared.The weight ratio of water-based polymer, deionized water, conductive particle, defoaming agent, dispersing agent and thickener is 20-30:120-150:35-55:0.2-0.5:0.4-0.6:0.2-0.4.Water-based polymer molecular chain contains catechol group structure, and the catechol group structure on it can form coordination bond, hydrogen bond and other various forces, so that water-based polymer can be firmly adhered as binder to different substrates.The polyaniline coating layer formed by in-situ polymerization on the surface of copper-silver core-shell powder can reduce the direct contact of high surface energy metal powder, prevent hard agglomeration, and be beneficial to uniform dispersion.

Description

Technical Field

[0001] This invention relates to the field of conductive paste production processes, specifically to a lithium battery conductive paste and its production process. Background Technology

[0002] Lithium-ion battery conductive pastes, as key auxiliary materials in the manufacture of lithium-ion battery electrodes, are widely used in power batteries, energy storage systems, and consumer electronics. Their core function is to construct an efficient conductive network between active material particles, thereby improving the battery's rate performance and cycle life. In practical applications, traditional conductive pastes often face two major technical bottlenecks. Firstly, nanoscale conductive agents (such as carbon black and carbon nanotubes) have large specific surface areas and high surface energies, making them prone to aggregation and difficult to disperse in solvents and electrode systems. Uneven dispersion can create localized conductive overloads or insulating zones, hindering uniform conductivity within the electrode and reducing the utilization rate of the active material. Secondly, the paste needs sufficient adhesion to ensure a strong bond between the electrode coating and the current collector (aluminum foil / copper foil). Insufficient adhesion can easily lead to active material peeling during battery charge-discharge volume changes, causing increased internal resistance, capacity decay, and even electrode detachment, seriously affecting battery safety and lifespan. Therefore, developing conductive pastes that combine high dispersibility and high adhesion is of great significance for improving electrode uniformity, structural stability and overall battery performance, and is one of the key directions for the improvement of current lithium battery material technology. Summary of the Invention

[0003] The purpose of this invention is to provide a lithium battery conductive paste that solves the problems of poor dispersion stability and low adhesion of traditional conductive pastes during use.

[0004] The objective of this invention can be achieved through the following technical solutions: A production process for a lithium battery conductive paste specifically includes the following steps: Aqueous polymer and deionized water are mixed evenly, and high-speed shearing is performed for 30-40 minutes at a speed of 5000-7000 r / min and a temperature of 0-20℃. The temperature is then raised to 40-50℃, and conductive particles, defoamer, dispersant and thickener are added while stirring. The mixture is then reacted for 4-5 hours to obtain lithium battery conductive slurry.

[0005] Furthermore, the weight ratio of the aqueous polymer, deionized water, conductive particles, defoamer, dispersant, and thickener is 20-30:120-150:35-55:0.2-0.5:0.4-0.6:0.2-0.4. The defoamer is one or more of defoamer GP330 and defoamer SNT-6000F mixed in any proportion. The dispersant is BYK-110 dispersant, and the thickener is RH-960 thickener.

[0006] Furthermore, the aqueous polymer is prepared by the following steps: Step A1: Mix 2,4-diaminobutyric acid and dichloromethane evenly, stir and add triethylamine at a speed of 80-100 r / min and a temperature of 0-5℃, and react for 10-30 min. Then add di-tert-butyl dicarbonate and react for 2-4 h to obtain intermediate 1. Step A2: Mix intermediate 1, N-hydroxysuccinimide and tetrahydrofuran evenly, stir and add 1-ethyl((3-dimethylaminopropyl)carbodiimide hydrochloride at 100-120 r / min and 0-5℃, and react for 1-2 h. Raise the temperature to 20-30℃, add dopamine hydrochloride, and react for 5-7 h to obtain intermediate 2. Mix intermediate 2 and diethyl ether evenly, stir and add trifluoroacetic acid at 50-70 r / min and 0-5℃, and react for 1-2 h to obtain intermediate 3. Step A3: Mix isophorone diisocyanate and N,N-dimethylformamide evenly, and stir at 80-100 r / min and 60-70℃ while adding 2,2-dimethylolpropionic acid, sodium 2,4-diaminobenzenesulfonate, 4,4'-dithiodiphenylamine and dibutyltin dilaurate. React for 4-6 h, then stir and add polyethylene glycol and triethanolamine, adjust the pH to 7, and react for 8-10 h to obtain the pretreated polymer. Mix the pretreated polymer, intermediate 3 and tetrahydrofuran evenly, and react at 100-120 r / min and 40-50℃ for 16-24 h to obtain the aqueous polymer.

[0007] Furthermore, the amounts of 2,4-diaminobutyric acid, dichloromethane, triethylamine, and ditert-butyl dicarbonate in step A1 are 10 mmol: 20 mL: 1.5 g: 12 mmol.

[0008] Furthermore, in step A2, the ratio of intermediate 1, N-hydroxysuccinimide, tetrahydrofuran, 1-ethyl((3-dimethylaminopropyl)carbodiimide hydrochloride and dopamine hydrochloride is 1 mol: 1.1 mol: 120 mL: 2.2 mmol: 1.5 mol, and the ratio of intermediate 2 and trifluoroacetic acid is 5 g: 8-10 mL.

[0009] Further, in step A3, the molar ratio of isophorone diisocyanate, 2,2-dimethylolpropionic acid, sodium 2,4-diaminobenzenesulfonate, 4,4'-dithiodiphenylamine, and polyethylene glycol is 1.5:0.2:0.2:0.05:0.4, the amount of dibutyltin dilaurate is 0.2-0.5% of the mass of isophorone diisocyanate, the average molecular weight of polyethylene glycol is 400, and the molar ratio of isocyanate groups on the pretreated polymer to amino groups on intermediate 3 is 1:1.5.

[0010] Furthermore, the conductive particles are made by the following steps: Step B1: Mix copper powder, ethylenediaminetetraacetic acid and deionized water evenly, stir and add silver nitrate solution under the conditions of 200-300 r / min, 30-40℃ and pH 10-11, and react for 8-10 h to obtain copper-silver core-shell powder. Step B2: Mix copper-silver core-shell powder, 3-mercaptopropionic acid and ethanol evenly, and react for 12-24 hours at a speed of 150-170 r / min and a temperature of 20-25℃ to obtain pretreated powder. Step B3: Mix aniline and hydrochloric acid evenly, stir for 15-20 minutes at a speed of 120-140 r / min and a temperature of 20-30℃, add pretreated powder and sodium dodecylbenzenesulfonate, react for 20-30 minutes, add deionized water solution of ammonium persulfate, and react for 3-5 hours to obtain conductive particles.

[0011] Furthermore, in step B1, the ratio of copper powder, ethylenediaminetetraacetic acid, deionized water, and silver nitrate solution is 1g:7-10g:100mL:30mL, and the molar concentration of silver nitrate is 0.1mol / L.

[0012] Furthermore, in step B2, the ratio of copper-silver core-shell powder, 3-mercaptopropionic acid, and ethanol is 1g:0.2g:100mL.

[0013] Furthermore, in step B3, the ratio of aniline, hydrochloric acid, pretreatment powder, sodium dodecylbenzenesulfonate, and deionized aqueous solution of ammonium persulfate is 0.3 mol: 100 mL: 3 g: 0.25 g: 100 mL, the molar concentration of hydrochloric acid is 1 mol / L, and the molar concentration of deionized aqueous solution of ammonium persulfate is 3 mol / L.

[0014] The beneficial effects of this invention are as follows: First, aqueous polymer and deionized water are subjected to high-speed shearing at low temperature to form a uniform and stable solution. Then, conductive particles, defoamer, dispersant and thickener are added to make the components uniformly mixed and stably form a conductive network, thus obtaining a lithium battery conductive slurry.

[0015] Aqueous polymer: Under alkaline conditions, the primary amines at both ends of the 2,4-diaminobutyric acid molecular chain nucleophilically attack the carbonyl carbon of di-tert-butyl dicarbonate, thereby protecting the highly reactive amino groups. Triethylamine neutralizes the generated acid, yielding intermediate 1. The carboxyl group on intermediate 1 is activated and reacts with the amino group on dopamine hydrochloride to form an amide bond, yielding intermediate 2. Then, under acid catalysis, a β-elimination reaction occurs, deprotecting the amino group and yielding intermediate 3. Under the action of a catalyst, excess isophorone diisocyanate first reacts with the amino groups on 2,2-dimethylolpropionic acid, sodium 2,4-diaminobenzenesulfonate, and 4,4'-dithiodiphenylamine to form urea bonds. Then, the isocyanate groups at the chain ends react with polyethylene glycol to form urethane groups, yielding a pretreated polymer. The isocyanate groups of the pretreated polymer chain react with the amino groups on intermediate 3 to form urea bonds, yielding the aqueous polymer.

[0016] Conductive particles: Under alkaline conditions, silver ions in silver nitrate solution undergo a displacement reaction with copper powder, depositing a silver layer on the surface of the copper powder. Ethylenediaminetetraacetic acid (EDTA) acts as a chelating agent, forming a stable complex with the generated copper ions to prevent copper ion precipitation or interference with the reaction, thus producing copper-silver core-shell powder. The thiol groups of 3-mercaptopropionic acid combine with the silver shell surface of the copper-silver core-shell powder to form an Ag-S bond self-assembled monolayer, thereby introducing carboxyl functional groups onto the particle surface. Hydrochloric acid and aniline form aniline salts, providing an acidic polymerization environment. Under the action of an initiator, the carboxyl functional groups can guide the nucleation and growth of polyaniline on the particle surface through hydrogen bonding or electrostatic interactions, forming a coating layer to obtain conductive particles.

[0017] The aqueous polymer molecular chain contains catechol groups, whose catechol structures can form various interactions such as coordination bonds and hydrogen bonds with metal oxides and active material surfaces, enabling the aqueous polymer to firmly adhere to different substrates as a binder. In aqueous slurries, water molecules on the particle surface can hinder the contact between the binder and the particles, but the catechol groups have strong hydrophilicity and hydrogen bonding capabilities, effectively displacing this water film and allowing the binder molecules to interact directly with the particle surface, thus maintaining high adhesion in a "wet" state. The hydrophilic and flexible polyethylene glycol segments and rigid benzene ring segments on the aqueous polymer molecular chain are incompatible and spontaneously undergo microphase separation. The hard segments firmly anchor the silicon anode particles, while the soft segments "absorb" volume changes through high curling and stretching. Combined with the dynamically reversible disulfide bond structure, this significantly suppresses electrode expansion. In-situ polymerization of copper-silver core-shell powder forms a polyaniline coating layer. This coating layer acts as a physical barrier, reducing direct contact between high surface energy metal powders, preventing hard agglomeration, and has better compatibility with aqueous polymers in the slurry, which is beneficial for uniform dispersion. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1: A production process for a lithium battery conductive paste, specifically including the following steps: Aqueous polymer and deionized water were mixed evenly and subjected to high-speed shearing for 30 minutes at a speed of 5000 r / min and a temperature of 0℃. The temperature was then raised to 40℃, and conductive particles, defoamer, dispersant and thickener were added while stirring. The mixture was reacted for 4 hours to obtain lithium battery conductive slurry.

[0020] The weight ratio of the aqueous polymer, deionized water, conductive particles, defoamer, dispersant, and thickener is 20:120:35:0.2:0.4:0.2. The defoamer is GP330, the dispersant is BYK-110, and the thickener is RH-960.

[0021] The aqueous polymer is prepared by the following steps: Step A1: Mix 2,4-diaminobutyric acid and dichloromethane evenly, stir and add triethylamine at 80 r / min and 0℃, react for 10 min, add ditert-butyl dicarbonate, react for 2 h to obtain intermediate 1. Step A2: Intermediate 1, N-hydroxysuccinimide and tetrahydrofuran were mixed evenly. Under the conditions of 100 r / min and 0℃, 1-ethyl((3-dimethylaminopropyl)carbodiimide hydrochloride was added and the mixture was stirred for 1 h. The temperature was raised to 20℃ and dopamine hydrochloride was added and the mixture was stirred for 5 h to obtain intermediate 2. Intermediate 2 and diethyl ether were mixed evenly. Under the conditions of 50 r / min and 0℃, trifluoroacetic acid was added and the mixture was stirred for 1 h to obtain intermediate 3. Step A3: Isophorone diisocyanate and N,N-dimethylformamide are mixed evenly. Under conditions of 80 r / min and 60 °C, 2,2-dimethylolpropionic acid, sodium 2,4-diaminobenzenesulfonate, 4,4'-dithiodiphenylamine and dibutyltin dilaurate are added while stirring and reacted for 4 h. Polyethylene glycol and triethanolamine are added while stirring and the pH is adjusted to 7. The reaction is carried out for 8 h to obtain the pretreated polymer. The pretreated polymer, intermediate 3 and tetrahydrofuran are mixed evenly and reacted under conditions of 100 r / min and 40 °C for 16 h to obtain the aqueous polymer.

[0022] The amounts of 2,4-diaminobutyric acid, dichloromethane, triethylamine, and ditert-butyl dicarbonate used in step A1 are 10 mmol: 20 mL: 1.5 g: 12 mmol.

[0023] In step A2, the ratio of intermediate 1, N-hydroxysuccinimide, tetrahydrofuran, 1-ethyl((3-dimethylaminopropyl)carbodiimide hydrochloride and dopamine hydrochloride is 1 mol: 1.1 mol: 120 mL: 2.2 mmol: 1.5 mol, and the ratio of intermediate 2 and trifluoroacetic acid is 5 g: 8 mL.

[0024] In step A3, the molar ratio of isophorone diisocyanate, 2,2-dimethylolpropionic acid, sodium 2,4-diaminobenzenesulfonate, 4,4'-dithiodiphenylamine, and polyethylene glycol is 1.5:0.2:0.2:0.05:0.4, the amount of isophorone diisocyanate is 1 mol, the amount of dibutyltin dilaurate is 0.2% of the mass of isophorone diisocyanate, the average molecular weight of polyethylene glycol is 400, the molar ratio of isocyanate groups on the pretreated polymer to amino groups on intermediate 3 is 1:1.5, and the amount of pretreated polymer is 1 mol.

[0025] The conductive particles are made by the following steps: Step B1: Mix copper powder, ethylenediaminetetraacetic acid and deionized water evenly, stir and add silver nitrate solution under the conditions of 200 r / min, 30℃ and pH 10, and react for 8 h to obtain copper-silver core-shell powder. Step B2: Mix copper-silver core-shell powder, 3-mercaptopropionic acid and ethanol evenly, and react for 12 hours at a speed of 150 r / min and a temperature of 20℃ to obtain pretreated powder. Step B3: Mix aniline and hydrochloric acid evenly, stir for 15 min at a speed of 120 r / min and a temperature of 20℃, add pretreated powder and sodium dodecylbenzenesulfonate, react for 20 min, add deionized water solution of ammonium persulfate, and react for 3 h to obtain conductive particles.

[0026] The ratio of copper powder, ethylenediaminetetraacetic acid, deionized water and silver nitrate solution used in step B1 is 1g:7g:100mL:30mL, and the molar concentration of silver nitrate is 0.1mol / L.

[0027] The ratio of copper-silver core-shell powder, 3-mercaptopropionic acid, and ethanol used in step B2 is 1g:0.2g:100mL.

[0028] In step B3, the ratio of aniline, hydrochloric acid, pretreatment powder, sodium dodecylbenzenesulfonate, and deionized water solution of ammonium persulfate is 0.3 mol: 100 mL: 3 g: 0.25 g: 100 mL, the molar concentration of hydrochloric acid is 1 mol / L, and the molar concentration of deionized water solution of ammonium persulfate is 3 mol / L.

[0029] Example 2: A production process for a lithium battery conductive paste, specifically including the following steps: Aqueous polymer and deionized water were mixed evenly and subjected to high-speed shearing for 35 minutes at a speed of 6000 r / min and a temperature of 10℃. The temperature was then raised to 45℃, and conductive particles, defoamer, dispersant and thickener were added. The mixture was reacted for 4 hours to obtain lithium battery conductive slurry.

[0030] The weight ratio of the aqueous polymer, deionized water, conductive particles, defoamer, dispersant, and thickener is 25:130:40:0.3:0.5:0.3. The defoamer is designated as SNT-6000F, the dispersant as BYK-110, and the thickener as RH-960.

[0031] The aqueous polymer is prepared by the following steps: Step A1: Mix 2,4-diaminobutyric acid and dichloromethane evenly, stir and add triethylamine at 90 r / min and 2℃, react for 20 min, add ditert-butyl dicarbonate, react for 3 h to obtain intermediate 1; Step A2: Intermediate 1, N-hydroxysuccinimide and tetrahydrofuran were mixed evenly. Under the conditions of 110 r / min and 2℃, 1-ethyl((3-dimethylaminopropyl)carbodiimide hydrochloride was added and the mixture was stirred for 1 h. The temperature was raised to 25℃ and dopamine hydrochloride was added and the mixture was stirred for 6 h to obtain intermediate 2. Intermediate 2 and diethyl ether were mixed evenly. Under the conditions of 60 r / min and 2℃, trifluoroacetic acid was added and the mixture was stirred for 1 h to obtain intermediate 3. Step A3: Isophorone diisocyanate and N,N-dimethylformamide are mixed evenly. Under conditions of 90 r / min and 65°C, 2,2-dimethylolpropionic acid, sodium 2,4-diaminobenzenesulfonate, 4,4'-dithiodiphenylamine and dibutyltin dilaurate are added while stirring and reacted for 5 h. Polyethylene glycol and triethanolamine are added while stirring and the pH is adjusted to 7. The reaction is carried out for 9 h to obtain a pretreated polymer. The pretreated polymer, intermediate 3 and tetrahydrofuran are mixed evenly and reacted under conditions of 110 r / min and 45°C for 20 h to obtain an aqueous polymer.

[0032] The amounts of 2,4-diaminobutyric acid, dichloromethane, triethylamine, and ditert-butyl dicarbonate used in step A1 are 10 mmol: 20 mL: 1.5 g: 12 mmol.

[0033] In step A2, the ratio of intermediate 1, N-hydroxysuccinimide, tetrahydrofuran, 1-ethyl((3-dimethylaminopropyl)carbodiimide hydrochloride and dopamine hydrochloride is 1 mol: 1.1 mol: 120 mL: 2.2 mmol: 1.5 mol, and the ratio of intermediate 2 and trifluoroacetic acid is 5 g: 9 mL.

[0034] In step A3, the molar ratio of isophorone diisocyanate, 2,2-dimethylolpropionic acid, sodium 2,4-diaminobenzenesulfonate, 4,4'-dithiodiphenylamine, and polyethylene glycol is 1.5:0.2:0.2:0.05:0.4. The amount of isophorone diisocyanate is 2 mol, the amount of dibutyltin dilaurate is 0.2% of the mass of isophorone diisocyanate, the average molecular weight of polyethylene glycol is 400, the molar ratio of isocyanate groups on the pretreated polymer to amino groups on intermediate 3 is 1:1.5, and the amount of pretreated polymer is 2 mol.

[0035] The conductive particles are made by the following steps: Step B1: Mix copper powder, ethylenediaminetetraacetic acid and deionized water evenly, stir and add silver nitrate solution under the conditions of 250 r / min, 35℃ and pH 10, and react for 9 h to obtain copper-silver core-shell powder. Step B2: Mix copper-silver core-shell powder, 3-mercaptopropionic acid and ethanol evenly, and react for 16 hours at a speed of 160 r / min and a temperature of 22℃ to obtain pretreated powder. Step B3: Mix aniline and hydrochloric acid evenly, stir for 16 min at a speed of 130 r / min and a temperature of 25℃, add pretreated powder and sodium dodecylbenzenesulfonate, react for 25 min, add deionized water solution of ammonium persulfate, and react for 4 h to obtain conductive particles.

[0036] In step B1, the ratio of copper powder, ethylenediaminetetraacetic acid, deionized water, and silver nitrate solution is 1g:8g:100mL:30mL, and the molar concentration of silver nitrate is 0.1mol / L.

[0037] The ratio of copper-silver core-shell powder, 3-mercaptopropionic acid, and ethanol used in step B2 is 1g:0.2g:100mL.

[0038] In step B3, the ratio of aniline, hydrochloric acid, pretreatment powder, sodium dodecylbenzenesulfonate, and deionized water solution of ammonium persulfate is 0.3 mol: 100 mL: 3 g: 0.25 g: 100 mL, the molar concentration of hydrochloric acid is 1 mol / L, and the molar concentration of deionized water solution of ammonium persulfate is 3 mol / L.

[0039] Example 3: A production process for a lithium battery conductive paste, specifically including the following steps: Aqueous polymer and deionized water were mixed evenly and subjected to high-speed shearing for 40 minutes at a speed of 7000 r / min and a temperature of 20℃. The temperature was then raised to 50℃, and conductive particles, defoamer, dispersant and thickener were added. The mixture was reacted for 5 hours to obtain lithium battery conductive slurry.

[0040] The weight ratio of the aqueous polymer, deionized water, conductive particles, defoamer, dispersant, and thickener is 30:150:55:0.5:0.6:0.4. The defoamer is GP330, the dispersant is BYK-110, and the thickener is RH-960.

[0041] The aqueous polymer is prepared by the following steps: Step A1: Mix 2,4-diaminobutyric acid and dichloromethane evenly, stir and add triethylamine at 100 r / min and 5℃, react for 30 min, add ditert-butyl dicarbonate, react for 4 h to obtain intermediate 1; Step A2: Intermediate 1, N-hydroxysuccinimide and tetrahydrofuran were mixed evenly. Under the conditions of 120 r / min and 5℃, 1-ethyl((3-dimethylaminopropyl)carbodiimide hydrochloride was added and the mixture was reacted for 2 h. The temperature was raised to 30℃ and dopamine hydrochloride was added and the mixture was reacted for 7 h to obtain intermediate 2. Intermediate 2 and diethyl ether were mixed evenly. Under the conditions of 70 r / min and 5℃, trifluoroacetic acid was added and the mixture was reacted for 2 h to obtain intermediate 3. Step A3: Isophorone diisocyanate and N,N-dimethylformamide are mixed evenly. Under conditions of 100 r / min and 70 °C, 2,2-dimethylolpropionic acid, sodium 2,4-diaminobenzenesulfonate, 4,4'-dithiodiphenylamine and dibutyltin dilaurate are added while stirring and reacted for 6 h. Polyethylene glycol and triethanolamine are added while stirring and the pH is adjusted to 7. The reaction is carried out for 10 h to obtain a pretreated polymer. The pretreated polymer, intermediate 3 and tetrahydrofuran are mixed evenly and reacted under conditions of 120 r / min and 50 °C for 24 h to obtain an aqueous polymer.

[0042] The amounts of 2,4-diaminobutyric acid, dichloromethane, triethylamine, and ditert-butyl dicarbonate used in step A1 are 10 mmol: 20 mL: 1.5 g: 12 mmol.

[0043] In step A2, the ratio of intermediate 1, N-hydroxysuccinimide, tetrahydrofuran, 1-ethyl((3-dimethylaminopropyl)carbodiimide hydrochloride and dopamine hydrochloride is 1 mol: 1.1 mol: 120 mL: 2.2 mmol: 1.5 mol, and the ratio of intermediate 2 and trifluoroacetic acid is 5 g: 10 mL.

[0044] In step A3, the molar ratio of isophorone diisocyanate, 2,2-dimethylolpropionic acid, sodium 2,4-diaminobenzenesulfonate, 4,4'-dithiodiphenylamine, and polyethylene glycol is 1.5:0.2:0.2:0.05:0.4. The amount of isophorone diisocyanate is 3 mol, the amount of dibutyltin dilaurate is 0.2% of the mass of isophorone diisocyanate, the average molecular weight of polyethylene glycol is 400, the molar ratio of isocyanate groups on the pretreated polymer to amino groups on intermediate 3 is 1:1.5, and the amount of pretreated polymer is 3 mol.

[0045] The conductive particles are made by the following steps: Step B1: Mix copper powder, ethylenediaminetetraacetic acid and deionized water evenly, stir and add silver nitrate solution under the conditions of 300 r / min, 40℃ and pH 11, and react for 10 h to obtain copper-silver core-shell powder. Step B2: Mix copper-silver core-shell powder, 3-mercaptopropionic acid and ethanol evenly, and react for 24 hours at a speed of 170 r / min and a temperature of 25℃ to obtain pretreated powder. Step B3: Mix aniline and hydrochloric acid evenly, stir for 20 min at a speed of 140 r / min and a temperature of 30℃, add pretreated powder and sodium dodecylbenzenesulfonate, react for 30 min, add deionized water solution of ammonium persulfate, and react for 5 h to obtain conductive particles.

[0046] In step B1, the ratio of copper powder, ethylenediaminetetraacetic acid, deionized water, and silver nitrate solution is 1g:10g:100mL:30mL, and the molar concentration of silver nitrate is 0.1mol / L.

[0047] The ratio of copper-silver core-shell powder, 3-mercaptopropionic acid, and ethanol used in step B2 is 1g:0.2g:100mL.

[0048] In step B3, the ratio of aniline, hydrochloric acid, pretreatment powder, sodium dodecylbenzenesulfonate, and deionized water solution of ammonium persulfate is 0.3 mol: 100 mL: 3 g: 0.25 g: 100 mL, the molar concentration of hydrochloric acid is 1 mol / L, and the molar concentration of deionized water solution of ammonium persulfate is 3 mol / L.

[0049] Comparative Example 1: Compared with Example 1, this comparative example uses 0.5g of PVDF dissolved in 5mL of NMP to prepare an adhesive solution, instead of the solution of water-based polymer and deionized water mixed evenly. The remaining steps are the same.

[0050] Comparative Example 2: This comparative example uses graphene instead of conductive particles, but the other steps are the same as in Example 1.

[0051] Comparative Example 3: This comparative example uses ethylene glycol instead of polyethylene glycol, while the other steps are the same as in Example 1.

[0052] Comparative Example 4: This comparative example uses copper-silver core-shell powder instead of conductive particles, while the other steps are the same as in Example 1.

[0053] Comparative Example 5: This comparative example uses 2,4-diaminobutyric acid instead of intermediate 3 compared to Example 1, with the other steps being the same.

[0054] Comparative Example 6: Compared with Example 1, this comparative example did not add 4,4'-dithiodiphenylamine in step A3, but the other steps were the same.

[0055] 4.3 g of lithium iron phosphate and 15 mL of lithium battery conductive slurry prepared in Examples 1-3 and Comparative Examples 1-6 were magnetically stirred for 1.5 h to obtain a uniformly mixed positive electrode slurry. The positive electrode slurry was coated onto an aluminum foil with a diameter of 10 mm. After the electrode was vacuum dried at 80 °C for 2 h, it was pressed at a pressure of 15 MPa and then vacuum dried at 80 °C for 12 h to obtain a positive electrode sheet. A CR2032 coin cell was prepared in an argon-atmosphere glove box using a lithium sheet as the negative electrode, a Celgard 2500 polyethylene porous membrane as the separator, and a 1 mol / L LiPF6 / EC-EMC-DMC (volume ratio 1:1:1) solution as the electrolyte.

[0056] The lithium iron phosphate electrode was subjected to constant current charge-discharge testing on the Blue Electric CT2001A testing system. The test temperature was maintained at 24℃, and the voltage range was 2.5-3.65V. First, it was cycled for 10 cycles at a current density of 0.2C, then the current density was changed to 170mA / g (1C) for 300 cycles. The specific charge-discharge test procedure was as follows: after resting for 3 minutes, it was charged to 3.65V; after resting for another 3 minutes, it was discharged to 2.5V, and cycled for 300 cycles. The discharge specific capacity and capacity retention of the lithium iron phosphate cathode were recorded after 100 cycles under 1C charge-discharge conditions.

[0057] After the battery was prepared, it was allowed to stand for 24 hours to allow the electrolyte to fully wet the electrodes. Then, AC impedance was measured on a PARSTAT2273 electrochemical workstation with an AC voltage amplitude of 5 mA and a frequency range between 10 Hz. -2 -10 5 Between Hz. An equivalent circuit model was used for fitting, and the charge transfer impedance was recorded.

[0058] Table 1 Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Discharge specific capacity (mAh / g) 150.2 153.2 156.1 132.1 122.8 144.4 126.8 96.5 145.1 Capacity retention rate (%) 95.8 96.4 97.2 88.4 84.3 93.6 86.9 72.4 93.9 Charge transfer impedance (Ω) 112.3 108.6 103.4 162.2 221.6 125.4 203.7 288.9 120.8 Table 1 shows that the CR2032 coin cells prepared in Examples 1-3, after 100 cycles under 1C charge-discharge conditions, exhibited a discharge specific capacity of 150.2-156.1 mAh / g, a capacity retention of 95.8-97.2%, and a charge transfer impedance of 103.4-112.3 Ω for the lithium iron phosphate cathode. This indicates that the electrode structure of the battery remains highly stable during long-term cycling, and the robust bonding interface successfully resists the volume expansion stress during charge-discharge processes, preventing active material stripping and ensuring the integrity of the reaction interface and the continuous unobstructed conductivity pathway. This demonstrates that the present invention possesses good dispersion stability and high adhesion.

[0059] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A production process for a lithium battery conductive paste, characterized in that: Specifically, the steps include the following: Aqueous polymer and deionized water are mixed evenly, subjected to high-speed shearing, heated, stirred and added with conductive particles, defoamer, dispersant and thickener, and reacted to obtain lithium battery conductive slurry; The weight ratio of the aqueous polymer, deionized water, conductive particles, defoamer, dispersant and thickener is 20-30:120-150:35-55:0.2-0.5:0.4-0.6:0.2-0.

4.

2. The production process of a lithium battery conductive paste according to claim 1, characterized in that: The aqueous polymer is prepared by the following steps: Step A1: Mix 2,4-diaminobutyric acid and dichloromethane, stir, add triethylamine, and react. Add ditert-butyl dicarbonate and react to obtain intermediate 1. Step A2: Intermediate 1, N-hydroxysuccinimide and tetrahydrofuran are mixed and stirred, and 1-ethyl((3-dimethylaminopropyl)carbonyldiimide hydrochloride is added to react. The mixture is heated, and dopamine hydrochloride is added to react and obtain intermediate 2. Intermediate 2 and diethyl ether are mixed and stirred, and trifluoroacetic acid is added to react and obtain intermediate 3. Step A3: Mix isophorone diisocyanate and N,N-dimethylformamide and add 2,2-dimethylolpropionic acid, sodium 2,4-diaminobenzenesulfonate, 4,4'-dithiodiphenylamine and dibutyltin dilaurate to react. Stir and add polyethylene glycol and triethanolamine, adjust the pH and react to obtain a pretreated polymer. Mix the pretreated polymer, intermediate 3 and tetrahydrofuran evenly and react to obtain an aqueous polymer.

3. The production process of a lithium battery conductive paste according to claim 2, characterized in that: The amounts of 2,4-diaminobutyric acid, dichloromethane, triethylamine, and ditert-butyl dicarbonate used in step A1 are 10 mmol: 20 mL: 1.5 g: 12 mmol.

4. The production process of a lithium battery conductive paste according to claim 2, characterized in that: In step A2, the ratio of intermediate 1, N-hydroxysuccinimide, tetrahydrofuran, 1-ethyl((3-dimethylaminopropyl)carbodiimide hydrochloride and dopamine hydrochloride is 1 mol: 1.1 mol: 120 mL: 2.2 mmol: 1.5 mol, and the ratio of intermediate 2 and trifluoroacetic acid is 5 g: 8-10 mL.

5. The production process of a lithium battery conductive paste according to claim 2, characterized in that: In step A3, the molar ratio of isophorone diisocyanate, 2,2-dimethylolpropionic acid, sodium 2,4-diaminobenzenesulfonate, 4,4'-dithiodiphenylamine, and polyethylene glycol is 1.5:0.2:0.2:0.05:0.

4. The amount of dibutyltin dilaurate is 0.2-0.5% of the mass of isophorone diisocyanate. The molar ratio of isocyanate groups on the pretreated polymer to amino groups on intermediate 3 is 1:1.

5.

6. The production process of a lithium battery conductive paste according to claim 1, characterized in that: The conductive particles are made by the following steps: Step B1: Mix copper powder, ethylenediaminetetraacetic acid and deionized water, stir and add silver nitrate solution to react and obtain copper-silver core-shell powder; Step B2: Mix copper-silver core-shell powder, 3-mercaptopropionic acid and ethanol evenly and react to obtain pretreated powder; Step B3: Mix and stir aniline and hydrochloric acid, add pretreated powder and sodium dodecylbenzenesulfonate, react, add deionized water solution of ammonium persulfate, react again, and obtain conductive particles.

7. The production process of a lithium battery conductive paste according to claim 6, characterized in that: The ratio of copper powder, ethylenediaminetetraacetic acid, deionized water and silver nitrate solution used in step B1 is 1g:7-10g:100mL:30mL.

8. The production process of a lithium battery conductive paste according to claim 6, characterized in that: The ratio of copper-silver core-shell powder, 3-mercaptopropionic acid, and ethanol used in step B2 is 1g:0.2g:100mL.

9. The production process of a lithium battery conductive paste according to claim 6, characterized in that: The ratio of the amount of aniline, hydrochloric acid, pretreated powder, sodium dodecylbenzenesulfonate and ammonium persulfate in the deionized aqueous solution in step B3 is 0.3 mol: 100 mL: 3 g: 0.25 g: 100 mL.

10. A conductive paste for lithium batteries, characterized in that: It is prepared by the production process according to any one of claims 1-9.