Preparation method and application of a conductive coating slurry for a sodium-ion battery

Abstract

The invention discloses a preparation method and application of a conductive coating slurry for sodium ion batteries. The conductive coating slurry comprises the following raw materials in parts by weight: 100-120 parts of polyurethane emulsion, 15-20 parts of modified graphene, 1-3 parts of benzoin ethyl ether, 3-5 parts of dispersant and 1-2 parts of leveling agent. After the conductive coating slurry is coated, it is irradiated with ultraviolet light, so that the double bonds in the polyurethane emulsion and the double bonds on the modified graphene are crosslinked, thereby increasing the crosslinking sites and enhancing the crosslinking density, achieving the effect of improving the water resistance of the coating. Moreover, the main chain of the modified monomer is an organosilicon chain segment, and the side chain contains a long-chain fluoroalkane, which can prevent water from entering the interior of the coating and increase the water resistance. The modified monomer reacts with isophorone diisocyanate to form a carbodiimide structure, which cooperates with the carbodiimide structure on the polyurethane molecular chain to react with the carboxyl groups generated by hydrolysis, achieving a neutralization effect and repairing the broken polymer chains, further enhancing the hydrolysis resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of sodium-ion batteries, and particularly relates to a preparation method and application of a conductive coating slurry for sodium-ion batteries. Background Art

[0002] The application of sodium-ion batteries is closely related to the positive and negative electrode materials of the batteries, and the performance of the positive and negative electrode materials directly affects the performance of the batteries. At present, for battery negative electrode materials, including carbon-based materials, transition metal oxides and sulfides, alloy materials, etc., carbon-coated aluminum foil is also a commonly used material for the negative electrode of sodium-ion batteries. However, the coating of carbon-coated aluminum foil has poor water resistance, which easily leads to instability at the interface between the electrolyte and the current collector. This instability will accelerate the occurrence of interfacial side reactions, increase the internal resistance of the battery, thereby reducing the cycle life and Coulomb efficiency of the battery. Moreover, the coating will react with the electrolyte to form an impedance layer, thus increasing the internal resistance of the battery and reducing the conductivity, which will affect the rate performance and charge-discharge speed of the battery. Therefore, a coating slurry with good water resistance is needed to solve this problem. Summary of the Invention

[0003] The purpose of the present invention is to provide a preparation method and application of a conductive coating slurry for sodium-ion batteries, which solves the problem of poor water resistance of the conductive coating slurry in the current carbon-coated aluminum foil for sodium-ion negative electrodes.

[0004] The purpose of the present invention can be achieved by the following technical solutions:

[0005] A preparation method of a conductive coating slurry for sodium-ion batteries specifically includes the following steps:

[0006] Step A1: Mix polycarbonate diol, modified monomer, isophorone diisocyanate and acetone evenly, and carry out a reaction for 1 - 2 h under the conditions of a rotation speed of 120 - 150 r / min and a temperature of 80 - 85 °C. Add castor oil and dibutyltin dilaurate, and carry out a reaction for 2 - 3 h. Add 2,2-bis(hydroxymethyl)propionic acid, and carry out a reaction for 2 - 3 h. Cool down to 40 - 50 °C, add allyl alcohol, and carry out a reaction for 1 - 2 h. Add triethylamine for neutralization, add deionized water, and remove ethyl ether by vacuum distillation to obtain a polyurethane emulsion.

[0007] Step A2: Disperse graphene in ethanol, and under the conditions of a rotation speed of 150 - 200 r / min and a temperature of 60 - 70 °C, stir and add KH570, and carry out a reaction for 3 - 5 h to obtain modified graphene. Weigh the following raw materials in parts by weight: 100 - 120 parts of polyurethane emulsion, 15 - 20 parts of modified graphene, 1 - 3 parts of benzoin ethyl ether, 3 - 5 parts of dispersant and 1 - 2 parts of leveling agent. Mix the raw materials evenly and store in the dark to obtain a conductive coating slurry for sodium-ion batteries.

[0008] Further, the dosage ratio of the polycarbonate diol, modified monomer, isophorone diisocyanate, castor oil, 2,2-bis(hydroxymethyl)propionic acid, allyl alcohol, and deionized water described in step A1 is 6 mmol∶2.5 mmol∶16 mmol∶1.5 mmol∶6 mmol∶1 mmol∶80 mL. The molecular weight of the polycarbonate diol is 1000, and the dosage of dibutyltin dilaurate is 2% of the mass of isophorone diisocyanate.

[0009] Further, the dosage of KH570 described in step A2 is 1% of the mass of graphene. The dispersant is one or a mixture of any proportions of OP-10, BYK-190, or BYK-191, and the leveling agent is one or a mixture of any proportions of BYK-306, BYK-310, or BYK-3033.

[0010] Further, the modified monomer is prepared by the following steps:

[0011] Step B1: Mix diethanolamine, benzyl chloroformate, sodium bicarbonate, and DMF, and react for 2 - 3 h under the conditions of a rotation speed of 120 - 150 r / min and a temperature of 25 - 30 °C to obtain intermediate 1. Mix intermediate 1, allyl bromide, sodium hydride, and DMF, and react for 3 - 5 h under the conditions of a rotation speed of 200 - 300 r / min and a temperature of 40 - 50 °C to obtain intermediate 2. Mix intermediate 2, 1H,1H,2H,2H-perfluorooctyl iodide, copper chloride, monoethanolamine, and DMF uniformly, and react for 3 - 5 h under the conditions of a rotation speed of 60 - 80 r / min and a temperature of 80 - 90 °C to obtain intermediate 3.

[0012] Step B2: Mix intermediate 3, palladium-carbon catalyst, and dioxane uniformly, and react for 3 - 5 h under the conditions of a temperature of 25 - 30 °C and a hydrogen atmosphere to obtain intermediate 4. Mix intermediate 4, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, sodium hydride, and DMF, and react for 3 - 5 h under the conditions of a rotation speed of 150 - 200 r / min and a temperature of 30 - 40 °C to obtain the modifier.

[0013] Step B3: Mix octamethylcyclotetrasiloxane, modifier, tetramethylammonium hydroxide, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, and dimethyl sulfoxide uniformly, introduce nitrogen protection, and react for 3 - 5 h under the conditions of a rotation speed of 150 - 200 r / min and a temperature of 105 - 110 °C to obtain diamine-terminated polysiloxane.

[0014] Step B4: Mix diamine-terminated polysiloxane, carbon disulfide, triethylamine, and DMF, introduce nitrogen for protection, and react at a rotation speed of 120 - 150 r / min and a temperature of 50 - 60 °C for 6 - 8 h to obtain modified polysiloxane. Mix the modified polysiloxane, sodium hydroxide, polyethylene glycol 400, and toluene evenly, stir and add sodium hypochlorite at a rotation speed of 120 - 150 r / min and a temperature of 55 - 65 °C, and react for 2 - 3 h to obtain a modified monomer.

[0015] Further, the molar ratio of diethanolamine, benzyl chloroformate, and sodium bicarbonate in Step B1 is 1∶1∶1.1, the molar ratio of Intermediate 1, allyl bromide, and sodium cyanide is 1∶2∶2.1, the molar ratio of Intermediate 2 and 1H,1H,2H,2H-perfluorooctyl iodide is 1∶2, the dosage of copper chloride is 2% of the sum of the masses of Intermediate 2 and 1H,1H,2H,2H-perfluorooctyl iodide, and the dosage of monoethanolamine is 1% of the sum of the masses of Intermediate 2 and 1H,1H,2H,2H-perfluorooctyl iodide.

[0016] Further, the mass ratio of Intermediate 3 and palladium-carbon catalyst in Step B2 is 20∶1, the molar ratio of Intermediate 4 and 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane is 4∶1, and the dosage of sodium hydride is 1% of the sum of the masses of Intermediate 4 and 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane.

[0017] Further, the molar ratio of octamethylcyclotetrasiloxane, modifier, tetramethylammonium hydroxide, and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane in Step B3 is 1.8∶0.5∶3∶2.

[0018] Further, the molar ratio of the alkyl group on the diamine-terminated polysiloxane and carbon disulfide in Step B4 is 2∶1, the dosage ratio of triethylamine is 3% of the mass of carbon disulfide, and the mass ratio of the modified polysiloxane, sodium hydroxide, polyethylene glycol 400, and sodium hypochlorite is 20∶1∶3∶120.

[0019] Advantages of the present invention: A conductive coating slurry for a sodium-ion battery prepared by the present invention comprises the following raw materials: polyurethane emulsion, modified graphene, benzoin ethyl ether, dispersant, and leveling agent. The polyurethane emulsion reacts with polycarbonate diol, modified monomer, and isophorone diisocyanate, then reacts with castor oil, and then reacts with 2,2-bis(hydroxymethyl)propionic acid to form a polyurethane prepolymer, and finally is terminated with allyl alcohol. The graphene is treated with KH570 to graft double bonds on the surface to obtain modified graphene.

[0020] The modified monomer is prepared from diethanolamine and treated with benzyl chloroformate to form secondary amine protection, obtaining intermediate 1. Intermediate 1 is reacted with allyl bromide, causing the hydroxyl group on intermediate 1 to react with the bromine atom site on allyl bromide, obtaining intermediate 2. 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8 - heptadecafluoro - 1 - iodooctane is reacted with intermediate 2, making the iodine atom site on 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8 - heptadecafluoro - 1 - iodooctane react with the double bond on intermediate 2, obtaining intermediate 3. Intermediate 3 is deprotected with palladium - carbon catalyst to obtain intermediate 4. Intermediate 4 and 2,4,6,8 - tetramethyl - 2,4,6,8 - tetravinylcyclotetrasiloxane are reacted under the action of sodium hydride, causing the secondary amine on intermediate 4 to graft with the double bond on 2,4,6,8 - tetramethyl - 2,4,6,8 - tetravinylcyclotetrasiloxane, obtaining the modifier. Octamethylcyclotetrasiloxane and the modifier are ring - opened and then reacted with 1,3 - bis(3 - aminopropyl)-1,1,3,3 - tetramethyldisiloxane to obtain diamine - terminated polysiloxane. The diamine - terminated polysiloxane is reacted with carbon disulfide to form a carbodiimide structure, obtaining the modified monomer.

[0021] After the conductive coating slurry is coated and irradiated with ultraviolet light, the double bonds in the polyurethane emulsion and the double bonds on the modified graphene can be cross - linked, thereby increasing the cross - linking sites and enhancing the cross - linking density, achieving the effect of improving the water resistance of the coating. Moreover, the main chain of the modified monomer is an organosilicon segment, and the side chain contains a long - chain fluoroalkane, which can prevent water from entering the interior of the coating and increase the water resistance. The modified monomer reacts with isophorone diisocyanate to form a carbodiimide structure, which cooperates with the carbodiimide structure on the polyurethane molecular chain, can react with the carboxyl groups generated by hydrolysis to achieve a neutralization effect, and repair the broken polymer chains, further enhancing the hydrolysis resistance. Detailed implementation manners

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0023] Example 1

[0024] A preparation method of a conductive coating slurry for sodium - ion batteries specifically includes the following steps:

[0025] Step A1: Mix polycarbonate diol, modified monomer, isophorone diisocyanate and acetone evenly. Under the conditions of a rotation speed of 120 r / min and a temperature of 80 °C, react for 1 h. Add castor oil and dibutyltin dilaurate, react for 2 h, add 2,2-bis(hydroxymethyl)propionic acid, react for 2 h, cool down to 40 °C, add allyl alcohol, react for 1 h, add triethylamine for neutralization, add deionized water, and remove ether by vacuum distillation to obtain a polyurethane emulsion;

[0026] Step A2: Disperse graphene in ethanol. Under the conditions of a rotation speed of 150 r / min and a temperature of 60 °C, stir and add KH570, react for 3 h to obtain modified graphene. Weigh the following raw materials by weight: 100 parts of polyurethane emulsion, 15 parts of modified graphene, 1 part of benzoin ethyl ether, 3 parts of dispersant, and 1 part of leveling agent. Mix the raw materials evenly and store in the dark to obtain a conductive coating slurry for sodium-ion batteries.

[0027] The dosage ratio of the polycarbonate diol, modified monomer, isophorone diisocyanate, castor oil, 2,2-bis(hydroxymethyl)propionic acid, allyl alcohol and deionized water described in Step A1 is 6 mmol∶2.5 mmol∶16 mmol∶1.5 mmol∶6 mmol∶1 mmol∶80 mL. The molecular weight of the polycarbonate diol is 1000, and the dosage of dibutyltin dilaurate is 2% of the mass of isophorone diisocyanate.

[0028] The dosage of KH570 described in Step A2 is 1% of the mass of graphene. The model of the dispersant is OP-10, and the model of the leveling agent is BYK-306.

[0029] The modified monomer is prepared by the following steps:

[0030] Step B1: Mix diethanolamine, benzyl chloroformate, sodium bicarbonate and DMF. Under the conditions of a rotation speed of 120 r / min and a temperature of 25 °C, react for 2 h to obtain Intermediate 1. Mix Intermediate 1, allyl bromide, sodium hydride and DMF. Under the conditions of a rotation speed of 200 r / min and a temperature of 40 °C, react for 3 h to obtain Intermediate 2. Mix Intermediate 2, 1H,1H,2H,2H-perfluorooctyl iodide, copper chloride, monoethanolamine and DMF evenly. Under the conditions of a rotation speed of 60 r / min and a temperature of 80 °C, react for 3 h to obtain Intermediate 3.

[0031] Step B2: Mix intermediate 3, palladium carbon catalyst, and dioxane uniformly. React for 3 h under the conditions of a temperature of 25 °C and a hydrogen atmosphere to obtain intermediate 4. Mix intermediate 4, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, sodium hydride, and DMF, and react for 3 h under the conditions of a rotation speed of 150 r / min and a temperature of 30 °C to obtain a modifier:

[0032] Step B3: Mix octamethylcyclotetrasiloxane, modifier, tetramethylammonium hydroxide, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, and dimethyl sulfoxide uniformly. Introduce nitrogen protection and react for 3 h under the conditions of a rotation speed of 150 r / min and a temperature of 105 °C to obtain diamine-terminated polysiloxane;

[0033] Step B4: Mix diamine-terminated polysiloxane, carbon disulfide, triethylamine, and DMF, introduce nitrogen protection, and react for 6 h under the conditions of a rotation speed of 120 r / min and a temperature of 50 °C to obtain modified polysiloxane. Mix modified polysiloxane, sodium hydroxide, polyethylene glycol 400, and toluene uniformly, stir and add sodium hypochlorite under the conditions of a rotation speed of 120 r / min and a temperature of 55 °C, and react for 2 h to obtain a modified monomer.

[0034] The molar ratio of diethanolamine, benzyl chloroformate, and sodium bicarbonate described in Step B1 is 1:1:1.1. The molar ratio of intermediate 1, allyl bromide, and sodium cyanide is 1:2:2.1. The molar ratio of intermediate 2 and 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro-1-iodooctane is 1:2. The dosage of copper chloride is 2% of the sum of the masses of intermediate 2 and 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro-1-iodooctane. The dosage of monoethanolamine is 1% of the sum of the masses of intermediate 2 and 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro-1-iodooctane.

[0035] The mass ratio of intermediate 3 and palladium carbon catalyst described in Step B2 is 20:1. The molar ratio of intermediate 4 and 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane is 4:1. The dosage of sodium hydride is 1% of the sum of the masses of intermediate 4 and 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane.

[0036] The molar ratio of octamethylcyclotetrasiloxane, modifier, tetramethylammonium hydroxide, and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane described in Step B3 is 1.8:0.5:3:2.

[0037] The molar ratio of the alkyl group on diamine-terminated polysiloxane and carbon disulfide described in Step B4 is 2:1. The dosage ratio of triethylamine is 3% of the mass of carbon disulfide. The mass ratio of modified polysiloxane, sodium hydroxide, polyethylene glycol 400, and sodium hypochlorite is 20:1:3:120.

[0038] Example 2

[0039] A preparation method of a conductive coating slurry for a sodium-ion battery specifically includes the following steps:

[0040] Step A1: Mix polycarbonate diol, a modified monomer, isophorone diisocyanate, and acetone evenly. Under the conditions of a rotation speed of 120 r / min and a temperature of 85 °C, react for 2 h. Add castor oil and dibutyltin dilaurate, react for 2 h, add 2,2-bis(hydroxymethyl)propionic acid, react for 3 h, cool down to 45 °C, add allyl alcohol, react for 1.5 h, add triethylamine for neutralization, add deionized water, and remove ethyl ether by vacuum distillation to obtain a polyurethane emulsion;

[0041] Step A2: Disperse graphene in ethanol. Under the conditions of a rotation speed of 150 r / min and a temperature of 65 °C, stir and add KH570, react for 4 h to obtain modified graphene. Weigh the following raw materials in parts by weight: 110 parts of polyurethane emulsion, 18 parts of modified graphene, 2 parts of benzoin ethyl ether, 4 parts of dispersant, and 1.5 parts of leveling agent. Mix the raw materials evenly and store in the dark to obtain a conductive coating slurry for a sodium-ion battery.

[0042] The dosage ratio of the polycarbonate diol, modified monomer, isophorone diisocyanate, castor oil, 2,2-bis(hydroxymethyl)propionic acid, allyl alcohol, and deionized water in Step A1 is 6 mmol∶2.5 mmol∶16 mmol∶1.5 mmol∶6 mmol∶1 mmol∶80 mL. The molecular weight of the polycarbonate diol is 1000, and the dosage of dibutyltin dilaurate is 2% of the mass of isophorone diisocyanate.

[0043] The dosage of KH570 in Step A2 is 1% of the mass of graphene. The model of the dispersant is BYK-190, and the model of the leveling agent is BYK-310.

[0044] The modified monomer is prepared by the following steps:

[0045] Step B1: Mix diethanolamine, benzyl chloroformate, sodium bicarbonate, and DMF. Under the conditions of a rotation speed of 120 r / min and a temperature of 30 °C, react for 2 h to obtain Intermediate 1. Mix Intermediate 1, allyl bromide, sodium hydride, and DMF. Under the conditions of a rotation speed of 300 r / min and a temperature of 45 °C, react for 4 h to obtain Intermediate 2. Mix Intermediate 2, 1H,1H,2H,2H-perfluorooctyl iodide, copper chloride, monoethanolamine, and DMF evenly. Under the conditions of a rotation speed of 80 r / min and a temperature of 85 °C, react for 4 h to obtain Intermediate 3.

[0046] Step B2: Mix intermediate 3, palladium carbon catalyst, and dioxane evenly. React for 4 h under the conditions of a temperature of 28°C and a hydrogen atmosphere to obtain intermediate 4. Mix intermediate 4, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, sodium hydride, and DMF, and react for 4 h under the conditions of a rotation speed of 200 r / min and a temperature of 35°C to obtain a modifier.

[0047] Step B3: Mix octamethylcyclotetrasiloxane, the modifier, tetramethylammonium hydroxide, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, and dimethyl sulfoxide evenly. Introduce nitrogen protection and react for 4 h under the conditions of a rotation speed of 150 r / min and a temperature of 110°C to obtain a diamine-terminated polysiloxane.

[0048] Step B4: Mix the diamine-terminated polysiloxane, carbon disulfide, triethylamine, and DMF, introduce nitrogen protection, and react for 7 h under the conditions of a rotation speed of 120 r / min and a temperature of 55°C to obtain a modified polysiloxane. Mix the modified polysiloxane, sodium hydroxide, polyethylene glycol 400, and toluene evenly, stir and add sodium hypochlorite under the conditions of a rotation speed of 120 r / min and a temperature of 60°C, and react for 3 h to obtain a modified monomer.

[0049] The molar ratio of diethanolamine, benzyl chloroformate, and sodium bicarbonate described in Step B1 is 1:1:1.1. The molar ratio of intermediate 1, allyl bromide, and sodium cyanide is 1:2:2.1. The molar ratio of intermediate 2 and 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro-1-iodooctane is 1:2. The dosage of copper chloride is 2% of the sum of the masses of intermediate 2 and 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro-1-iodooctane. The dosage of monoethanolamine is 1% of the sum of the masses of intermediate 2 and 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro-1-iodooctane.

[0050] The mass ratio of intermediate 3 and palladium carbon catalyst described in Step B2 is 20:1. The molar ratio of intermediate 4 and 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane is 4:1. The dosage of sodium hydride is 1% of the sum of the masses of intermediate 4 and 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane.

[0051] The molar ratio of octamethylcyclotetrasiloxane, the modifier, tetramethylammonium hydroxide, and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane described in Step B3 is 1.8:0.5:3:2.

[0052] The molar ratio of the alkyl group on the diamine-terminated polysiloxane and carbon disulfide described in Step B4 is 2:1. The dosage ratio of triethylamine is 3% of the mass of carbon disulfide. The mass ratio of the modified polysiloxane, sodium hydroxide, polyethylene glycol 400, and sodium hypochlorite is 20:1:3:120.

[0053] Example 3

[0054] A preparation method of a conductive coating slurry for a sodium-ion battery specifically includes the following steps:

[0055] Step A1: Mix polycarbonate diol, a modified monomer, isophorone diisocyanate, and acetone evenly. Under the conditions of a rotation speed of 150 r / min and a temperature of 85 °C, react for 2 h. Add castor oil and dibutyltin dilaurate, react for 3 h, add 2,2-bis(hydroxymethyl)propionic acid, react for 3 h, cool down to 50 °C, add allyl alcohol, react for 2 h, add triethylamine for neutralization, add deionized water, and remove ether by vacuum distillation to obtain a polyurethane emulsion;

[0056] Step A2: Disperse graphene in ethanol. Under the conditions of a rotation speed of 200 r / min and a temperature of 70 °C, stir and add KH570, react for 5 h to obtain modified graphene. Weigh the following raw materials in parts by weight: 120 parts of polyurethane emulsion, 20 parts of modified graphene, 3 parts of benzoin ethyl ether, 5 parts of dispersant, and 2 parts of leveling agent. Mix the raw materials evenly and store in the dark to obtain a conductive coating slurry for a sodium-ion battery.

[0057] The dosage ratio of the polycarbonate diol, modified monomer, isophorone diisocyanate, castor oil, 2,2-bis(hydroxymethyl)propionic acid, allyl alcohol, and deionized water described in Step A1 is 6 mmol∶2.5 mmol∶16 mmol∶1.5 mmol∶6 mmol∶1 mmol∶80 mL. The molecular weight of the polycarbonate diol is 1000, and the dosage of dibutyltin dilaurate is 2% of the mass of isophorone diisocyanate.

[0058] The dosage of KH570 described in Step A2 is 1% of the mass of graphene. The dispersant model is BYK-191, and the leveling agent model is BYK-3033.

[0059] The modified monomer is prepared by the following steps:

[0060] Step B1: Mix diethanolamine, benzyl chloroformate, sodium bicarbonate, and DMF. Under the conditions of a rotation speed of 150 r / min and a temperature of 30 °C, react for 3 h to obtain Intermediate 1. Mix Intermediate 1, allyl bromide, sodium hydride, and DMF. Under the conditions of a rotation speed of 300 r / min and a temperature of 50 °C, react for 5 h to obtain Intermediate 2. Mix Intermediate 2, 1H,1H,2H,2H-perfluorooctyl iodide, copper chloride, monoethanolamine, and DMF evenly. Under the conditions of a rotation speed of 80 r / min and a temperature of 90 °C, react for 5 h to obtain Intermediate 3.

[0061] Step B2: Mix intermediate 3, palladium carbon catalyst and dioxane uniformly, and react for 5 h under the conditions of a temperature of 30 °C and a hydrogen atmosphere to obtain intermediate 4. Mix intermediate 4, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, sodium hydride and DMF, and react for 5 h under the conditions of a rotation speed of 200 r / min and a temperature of 40 °C to obtain a modifier.

[0062] Step B3: Mix octamethylcyclotetrasiloxane, modifier, tetramethylammonium hydroxide, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and dimethyl sulfoxide uniformly, introduce nitrogen protection, and react for 5 h under the conditions of a rotation speed of 200 r / min and a temperature of 110 °C to obtain a diamine-terminated polysiloxane.

[0063] Step B4: Mix diamine-terminated polysiloxane, carbon disulfide, triethylamine and DMF, introduce nitrogen protection, and react for 8 h under the conditions of a rotation speed of 150 r / min and a temperature of 60 °C to obtain a modified polysiloxane. Mix the modified polysiloxane, sodium hydroxide, polyethylene glycol 400 and toluene uniformly, stir and add sodium hypochlorite under the conditions of a rotation speed of 150 r / min and a temperature of 65 °C, and react for 3 h to obtain a modified monomer.

[0064] The molar ratio of diethanolamine, benzyl chloroformate and sodium bicarbonate described in Step B1 is 1:1:1.1. The molar ratio of intermediate 1, allyl bromide and sodium cyanide is 1:2:2.1. The molar ratio of intermediate 2 and 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro-1-iodooctane is 1:2. The dosage of copper chloride is 2% of the sum of the masses of intermediate 2 and 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro-1-iodooctane. The dosage of monoethanolamine is 1% of the sum of the masses of intermediate 2 and 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro-1-iodooctane.

[0065] The mass ratio of intermediate 3 and palladium carbon catalyst described in Step B2 is 20:1. The molar ratio of intermediate 4 and 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane is 4:1. The dosage of sodium hydride is 1% of the sum of the masses of intermediate 4 and 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane.

[0066] The molar ratio of octamethylcyclotetrasiloxane, modifier, tetramethylammonium hydroxide and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane described in Step B3 is 1.8:0.5:3:2.

[0067] The molar ratio of the alkyl group on the diamine-terminated polysiloxane and carbon disulfide described in Step B4 is 2:1. The dosage ratio of triethylamine is 3% of the mass of carbon disulfide. The mass ratio of the modified polysiloxane, sodium hydroxide, polyethylene glycol 400 and sodium hypochlorite is 20:1:3:120.

[0068] Comparative Example 1

[0069] In this comparative example, graphene was used instead of modified graphene compared with Example 1, and the remaining steps were the same.

[0070] Comparative Example 2

[0071] In this comparative example, castor oil was not added compared with Example 1, and the remaining steps were the same.

[0072] Comparative Example 3

[0073] In this comparative example, allyl alcohol was not added compared with Example 1, and the remaining steps were the same.

[0074] Comparative Example 4

[0075] In this comparative example, the modifier was not added compared with Example 1, and the remaining steps were the same.

[0076] Comparative Example 5

[0077] In this comparative example, diamine-terminated polysiloxane was used instead of the modified monomer compared with Example 1, and the remaining steps were the same.

[0078] The conductive coating slurries prepared in Examples 1-3 and Comparative Examples 1-5 were tested according to the standard of GB / T1733-1993, soaked for 24h, 48h and 120h, and the state of the paint film was observed. The test results are shown in the following table.

[0079]

[0080]

[0081] It can be seen from the above table that the present application has good water resistance.

[0082] The above content is only an example and explanation of the concept of the present invention. Those skilled in the art of the present technology make various modifications or supplements or use similar methods to replace the specific embodiments described, as long as they do not deviate from the concept of the invention or exceed the scope defined by this claim book, they should all belong to the protection scope of the present invention.

Claims

1. A preparation method of a conductive coating slurry for a sodium-ion battery, characterized in that: Specifically, it includes the following steps: Step A1: Mix and react polycarbonate diol, modified monomer, isophorone diisocyanate and acetone, add castor oil and dibutyltin dilaurate, react, add 2,2-bis(hydroxymethyl)propionic acid, react, cool down and add allyl alcohol, react, add triethylamine for neutralization, add deionized water, and remove acetone by vacuum distillation to obtain a polyurethane emulsion; Step A2: Disperse graphene in ethanol, stir and add KH570, react to obtain modified graphene, weigh the following raw materials in parts by weight: 100 - 120 parts of polyurethane emulsion, 15 - 20 parts of modified graphene, 1 - 3 parts of benzoin ethyl ether, 3 - 5 parts of dispersant and 1 - 2 parts of leveling agent, mix the raw materials evenly, store in the dark to obtain a conductive coating slurry for sodium-ion batteries; The modified monomer is prepared by the following steps: Step B1: Mix and react diethanolamine, benzyl chloroformate, sodium bicarbonate and DMF to obtain intermediate 1, mix intermediate 1, allyl bromide, sodium hydride and DMF to react to obtain intermediate 2, mix intermediate 2, 1H,1H,2H,2H-perfluorooctyl iodide, copper chloride, monoethanolamine and DMF to react to obtain intermediate 3; Step B2: Mix intermediate 3, palladium-carbon catalyst and dioxane evenly, react under the conditions of a temperature of 25 - 30 °C and a hydrogen atmosphere to obtain intermediate 4, mix intermediate 4, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, sodium hydride and DMF to react to obtain a modifier; Step B3: Mix octamethylcyclotetrasiloxane, modifier, tetramethylammonium hydroxide, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and dimethyl sulfoxide evenly, introduce nitrogen for protection, and react to obtain a diamine-terminated polysiloxane; Step B4: Mix diamine-terminated polysiloxane, carbon disulfide, triethylamine and DMF, introduce nitrogen for protection, react to obtain a modified polysiloxane, mix the modified polysiloxane, sodium hydroxide, polyethylene glycol 400 and toluene evenly, stir and add sodium hypochlorite, react to obtain a modified monomer.

2. The preparation method of a conductive coating slurry for a sodium ion battery according to claim 1, wherein: The dosage ratio of the polycarbonate diol, modified monomer, isophorone diisocyanate, castor oil, 2,2-bis(hydroxymethyl)propionic acid, allyl alcohol and deionized water in Step A1 is 6 mmol:2.5 mmol:16 mmol:1.5 mmol:6 mmol:1 mmol:80 mL.

3. The preparation method of a conductive coating slurry for a sodium-ion battery according to claim 1, characterized in that: The dosage of KH570 in Step A2 is 1% of the mass of graphene.

4. The preparation method of a conductive coating slurry for a sodium ion battery according to claim 1, characterized in that: The molar ratio of diethanolamine, benzyl chloroformate and sodium bicarbonate in Step B1 is 1:1:1.1, the molar ratio of intermediate 1, allyl bromide and sodium cyanide is 1:2:2.1, and the molar ratio of intermediate 2 and 1H,1H,2H,2H-perfluorooctyl iodide is 1:

2.

5. The preparation method of a conductive coating slurry for a sodium-ion battery according to claim 1, characterized in that: The mass ratio of intermediate 3 and palladium-carbon catalyst in Step B2 is 20:1, and the molar ratio of intermediate 4 and 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane is 4:

1.

6. The preparation method of a conductive coating slurry for a sodium-ion battery according to claim 1, wherein: The molar ratio of octamethylcyclotetrasiloxane, modifier, tetramethylammonium hydroxide, and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane described in step B3 is 1.8:0.5:3:

2.

7. The preparation method of a conductive coating slurry for a sodium-ion battery according to claim 1, wherein: The molar ratio of amino groups on the diamine-terminated polysiloxane described in step B4 to carbon disulfide is 2:1, and the mass ratio of the modified polysiloxane, sodium hydroxide, polyethylene glycol 400, and sodium hypochlorite is 20:1:3:

120.

8. Application of the method for preparing the conductive coating paste according to any one of claims 1-7 in sodium-ion battery carbon-coated aluminum foil.

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