A fast-charging high-capacity artificial graphite negative electrode material and a preparation method thereof

Abstract

The application discloses a kind of fast charging high capacity artificial graphite negative material and preparation method thereof, ultrasonic mixing is carried out to cobalt acetate, modified ligand, modified additive and DMF and adding deionized water and modified filler, after ultrasonic treatment, reaction is heated, supernatant is removed by centrifugation, and drying treatment is carried out, to obtain fast charging high capacity artificial graphite negative material, when cobalt acetate, modified ligand, modified additive and modified filler are blended and react, carboxyl on modified ligand and carboxyl on modified additive can form coordination bond with cobalt ion of cobalt acetate, and then form cobalt metal organic framework on the surface of modified filler, fluorine element in modified ligand can react with lithium to form lithium fluoride, effectively block electron penetration, reduce side reaction, promote lithium uniform deposition, prevent dendrite from piercing diaphragm, reduce lithium ion diffusion energy barrier, realize fast charge and discharge, pyridine group on the surface of modified filler can provide lone pair electron, as lithium ion binding site, form pseudo-capacitance and then increase capacity.

Description

Technical Field

[0001] This invention relates to the field of anode material preparation technology, specifically to a fast-charging high-capacity artificial graphite anode material and its preparation method. Background Technology

[0002] With the increasing portability and intelligence of electronic products, the performance requirements for batteries are rising. Against the backdrop of the growing demand for fast charging and discharging, developing batteries that are both fast-charging and high-capacity has become a research hotspot. Generally speaking, traditional batteries often present an irreconcilable contradiction between charging / discharging speed and battery capacity. On the one hand, traditional graphite anode materials are widely used to increase battery capacity. However, these materials are prone to thermal runaway during fast charging, leading to reduced battery safety. On the other hand, traditional lithium-ion batteries often sacrifice cycle stability and fast-charging capability in pursuit of high capacity. Summary of the Invention

[0003] The purpose of this invention is to provide a fast-charging, high-capacity artificial graphite anode material and its preparation method, which solves the problems of low battery charging speed and significant capacity reduction after multiple charge-discharge cycles.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A method for preparing a fast-charging, high-capacity artificial graphite anode material specifically includes the following steps:

[0006] Step A1: Mix p-dibromobenzene and tetrahydrofuran evenly, purge with argon gas, add n-butyllithium and n-hexane at a rotation speed of 150-200 r / min and a temperature of -78℃, and react for 2-3 h. Then add tetrachlorosilane, raise the temperature to 0℃, and react for 2-3 h. Raise the temperature to 20-25℃ and continue the reaction for 10-15 h to obtain the intermediate.

[0007] Step A2: Mix the intermediate and tetrahydrofuran evenly, under argon protection, at a rotation speed of 120-150 r / min and a temperature of -78℃, add n-butyllithium and n-hexane, and react for 2-3 hours. Then, introduce carbon dioxide gas and continue the reaction for 2-3 hours. After quenching with saturated ammonium chloride aqueous solution, add hydrochloric acid aqueous solution until the pH value is 3 to obtain the modified ligand.

[0008] Step A3: Mix cobalt acetate, modified ligand, modified additive and DMF evenly, sonicate at a frequency of 20-30kHz and a temperature of 25-30℃, add deionized water and modified filler, sonicate for 20-30min, then heat to 160-170℃ and react for 20-25h, centrifuge to remove supernatant, dry to obtain fast-charging high-capacity artificial graphite anode material.

[0009] Furthermore, the ratio of p-dibromobenzene, tetrahydrofuran, p-dibromobenzene, n-hexane, and tetrachlorosilane used in step A1 is 4 mmol: 20 mL: 4 mmol: 1.6 mL: 1 mmol.

[0010] Furthermore, the ratio of the intermediate, tetrahydrofuran, n-butyllithium, n-hexane, and carbon dioxide gas used in step A2 is 1 mmol: 20 mL: 4 mmol: 1.6 mL: 90 mL.

[0011] Furthermore, the ratio of cobalt acetate, modified ligand, modified additive, DMF, deionized water and modified filler in step A3 is 4 mmol:6 mmol:0.2 g:15 mL:15 mL:1 g.

[0012] Furthermore, the modified additive is prepared by the following steps:

[0013] Step B1: Tetramethylcyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetra(3,3,3-trifluoropropyl)cyclotetrasiloxane, tetramethylammonium hydroxide and dimethyl sulfoxide are mixed and purged with nitrogen. The mixture is reacted at a speed of 150-200 r / min and a temperature of 80-90℃ for 6-8 hours. Then hexamethyldisiloxane is added and the reaction is continued for 3-5 hours. The temperature is then raised to 105-110℃ and the reaction is continued for 2-3 hours to obtain modified polysiloxane.

[0014] Step B2: Mix 5-hydroxyisophthalic acid and tetrahydrofuran evenly, purge with argon gas, stir and add triethylamine and acryloyl chloride at 200-300 r / min and 0-5℃, heat to 20-25℃ and react for 8-12 h, then add dilute hydrochloric acid to adjust the pH to 2-3 to obtain the modifier. Mix the modifier, modified polysiloxane, chloroplatinic acid and DMF evenly, purge with nitrogen gas, and react for 6-8 h at 150-200 r / min and 75-85℃ to obtain the modified additive.

[0015] Furthermore, the ratio of tetramethylcyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetra(3,3,3-trifluoropropyl)cyclotetrasiloxane, tetramethylammonium hydroxide, hexamethyldisiloxane and dimethyl sulfoxide in step B1 is 0.2 mol:1 mol:1.5 mol:1 mol:5 mL.

[0016] Furthermore, in step B2, the molar ratio of 5-hydroxyisophthalic acid, triethylamine, and acryloyl chloride is 1:3:1.1, the molar ratio of the Si-H bonds on the modifier and the modified polysiloxane is 1:1, and the amount of chloroplatinic acid is 30 ppm of the sum of the mass of the modifier and the modified polysiloxane.

[0017] Furthermore, the modified filler is prepared by the following steps:

[0018] Graphene oxide, 4-aminopyridine, dicyclohexylcarbodiimide, and DMF were mixed and purged with nitrogen. The mixture was then reacted for 3-5 hours at a rotation speed of 300-500 r / min and a temperature of 25-30℃ to obtain pretreated graphene. The pretreated graphene was dispersed in deionized water, and ammonia was added to adjust the pH to 10. The mixture was then stirred and hydrazine hydrate was added at a rotation speed of 200-300 r / min and a temperature of 95-98℃ to obtain modified filler.

[0019] Furthermore, the molar ratio of carboxyl groups, 4-aminopyridine, and dicyclohexylcarbodiimide on the graphene oxide is 1:1:1.1, and the amounts of pretreated graphene, deionized water, and hydrazine hydrate are 100mg:200mL:1mL.

[0020] The beneficial effects of this invention are as follows: This invention prepares a fast-charging high-capacity artificial graphite anode material by mixing cobalt acetate, modified ligands, modified additives and DMF, ultrasonicating, adding deionized water and modified filler, ultrasonicating, heating and reacting, centrifuging to remove the supernatant, and drying to obtain the fast-charging high-capacity artificial graphite anode material. The modified ligand is prepared by first exchanging halogen with lithium in the presence of n-butyllithium, and then nucleophilically substituting it with tetrachlorosilane to obtain an intermediate. The intermediate is then subjected to halogen-lithium exchange with n-butyl, and then nucleophilically added to form a carboxyl group in the presence of carbon dioxide to obtain the modified ligand.

[0021] The modified additive is prepared by ring-opening condensation of tetramethylcyclotetrasiloxane and 2,4,6,8-tetramethyl-2,4,6,8-tetra(3,3,3-trifluoropropyl)cyclotetrasiloxane as raw materials, followed by end-capping with hexamethyldisiloxane to obtain modified polysiloxane. 5-hydroxyisophthalic acid and acryloyl chloride are reacted to react the hydroxyl groups on 5-hydroxyisophthalic acid with the acryloyl chloride to obtain a modifier. The modifier is then reacted with modified polysiloxane to react the double bonds on the modifier with the Si-H bonds on the modified polysiloxane to obtain the modified additive.

[0022] Graphene oxide was reacted with 4-aminopyridine to dehydrate the carboxyl groups on the graphene oxide and the amino groups on the 4-aminopyridine, thus obtaining pretreated graphene. The pretreated graphene was then reduced with hydrazine hydrate to obtain a modified filler.

[0023] When cobalt acetate, modified ligands, modified additives, and modified fillers are blended, the carboxyl groups on the modified ligands and the modified additives form coordination bonds with cobalt ions in cobalt acetate, thereby forming a cobalt metal-organic framework on the surface of the modified filler. This ensures that the internal graphite layer does not expand during lithium ion insertion and extraction, thus improving battery life. The modified ligands contain silicon, and the modified additives contain organosilicon segments and fluorine. Silicon and organosilicon segments can suppress the expansion of the negative electrode material, while fluorine can react with lithium to form lithium fluoride, effectively blocking electron penetration, reducing side reactions, promoting uniform lithium deposition, preventing dendrites from piercing the separator, lowering the lithium ion diffusion barrier, and enabling rapid charging and discharging. The pyridine groups on the surface of the modified filler can provide lone pairs of electrons as binding sites for lithium ions, forming pseudocapacitance and increasing capacity. Detailed Implementation

[0024] 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.

[0025] Example 1: A method for preparing a fast-charging, high-capacity artificial graphite anode material, specifically including the following steps:

[0026] Step A1: Mix p-dibromobenzene and tetrahydrofuran evenly, purge with argon gas, add n-butyllithium and n-hexane at a speed of 150 r / min and a temperature of -78℃, and react for 2 h. Then add tetrachlorosilane, raise the temperature to 0℃, and react for 2 h. Raise the temperature to 20℃ and continue the reaction for 10 h to obtain the intermediate.

[0027] Step A2: Mix the intermediate and tetrahydrofuran evenly, under argon protection, at a rotation speed of 120 r / min and a temperature of -78℃, add n-butyllithium and n-hexane, and react for 2 hours. Then, introduce carbon dioxide gas and continue the reaction for 2 hours. After quenching with saturated ammonium chloride aqueous solution, add hydrochloric acid aqueous solution until the pH value is 3 to obtain the modified ligand.

[0028] Step A3: Mix cobalt acetate, modified ligand, modified additive and DMF evenly, sonicate at 20kHz and 25℃, add deionized water and modified filler, sonicate for 20min, heat to 160℃ and react for 20h, centrifuge to remove supernatant and dry to obtain fast-charging high-capacity artificial graphite anode material.

[0029] The ratio of p-dibromobenzene, tetrahydrofuran, p-dibromobenzene, n-hexane, and tetrachlorosilane used in step A1 is 4 mmol: 20 mL: 4 mmol: 1.6 mL: 1 mmol.

[0030] The ratio of the intermediate, tetrahydrofuran, n-butyllithium, n-hexane, and carbon dioxide gas used in step A2 is 1 mmol: 20 mL: 4 mmol: 1.6 mL: 90 mL.

[0031] The ratio of cobalt acetate, modified ligand, modified additive, DMF, deionized water and modified filler in step A3 is 4 mmol: 6 mmol: 0.2 g: 15 mL: 15 mL: 1 g.

[0032] The modified additive is prepared by the following steps:

[0033] Step B1: Tetramethylcyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetra(3,3,3-trifluoropropyl)cyclotetrasiloxane, tetramethylammonium hydroxide and dimethyl sulfoxide were mixed and purged with nitrogen. The mixture was reacted at 150 r / min and 80 °C for 6 h. Then hexamethyldisiloxane was added and the reaction was continued for 3 h. The temperature was raised to 105 °C and the reaction was continued for 2 h to obtain the modified polysiloxane.

[0034] Step B2: Mix 5-hydroxyisophthalic acid and tetrahydrofuran evenly, purge with argon gas, stir at 200 r / min and 0℃, add triethylamine and acryloyl chloride, heat to 20℃ and react for 8 h, then add dilute hydrochloric acid to pH 2 to obtain the modifier. Mix the modifier, modified polysiloxane, chloroplatinic acid and DMF evenly, purge with nitrogen gas, and react at 150 r / min and 75℃ for 6 h to obtain the modified additive.

[0035] The ratio of tetramethylcyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetra(3,3,3-trifluoropropyl)cyclotetrasiloxane, tetramethylammonium hydroxide, hexamethyldisiloxane and dimethyl sulfoxide in step B1 is 0.2 mol: 1 mol: 1.5 mol: 1 mol: 5 mL.

[0036] In step B2, the molar ratio of 5-hydroxyisophthalic acid, triethylamine, and acryloyl chloride is 1:3:1.1, the molar ratio of the Si-H bonds on the modifier and the modified polysiloxane is 1:1, and the amount of chloroplatinic acid is 30 ppm of the sum of the mass of the modifier and the modified polysiloxane.

[0037] The modified filler is prepared by the following steps:

[0038] Graphene oxide, 4-aminopyridine, dicyclohexylcarbodiimide, and DMF were mixed and purged with nitrogen. The mixture was reacted for 3 hours at a speed of 300 r / min and a temperature of 25 °C to obtain pretreated graphene. The pretreated graphene was dispersed in deionized water, and ammonia was added to adjust the pH to 10. The mixture was stirred and hydrazine hydrate was added at a speed of 200 r / min and a temperature of 95 °C. The mixture was then reacted for 10 hours to obtain the modified filler.

[0039] The molar ratio of carboxyl groups, 4-aminopyridine, and dicyclohexylcarbodiimide on the graphene oxide is 1:1:1.1, and the amounts of pretreated graphene, deionized water, and hydrazine hydrate are 100 mg: 200 mL: 1 mL.

[0040] Example 2: A method for preparing a fast-charging, high-capacity artificial graphite anode material, specifically including the following steps:

[0041] Step A1: Mix p-dibromobenzene and tetrahydrofuran evenly, purge with argon gas, add n-butyllithium and n-hexane at a speed of 150 r / min and a temperature of -78℃, and react for 3 h. Then add tetrachlorosilane, raise the temperature to 0℃, and react for 2 h. Raise the temperature to 25℃ and continue the reaction for 12 h to obtain the intermediate.

[0042] Step A2: Mix the intermediate and tetrahydrofuran evenly, under argon protection, at a rotation speed of 120 r / min and a temperature of -78℃, add n-butyllithium and n-hexane, and react for 3 hours. Then, introduce carbon dioxide gas and continue the reaction for 2 hours. After quenching with saturated ammonium chloride aqueous solution, add hydrochloric acid aqueous solution until the pH value is 3 to obtain the modified ligand.

[0043] Step A3: Mix cobalt acetate, modified ligand, modified additive and DMF evenly, sonicate at a frequency of 25kHz and a temperature of 25℃, add deionized water and modified filler, sonicate for 25min, heat to 165℃ and react for 20h, centrifuge to remove supernatant and dry to obtain fast-charging high-capacity artificial graphite anode material.

[0044] The ratio of p-dibromobenzene, tetrahydrofuran, p-dibromobenzene, n-hexane, and tetrachlorosilane used in step A1 is 4 mmol: 20 mL: 4 mmol: 1.6 mL: 1 mmol.

[0045] The ratio of the intermediate, tetrahydrofuran, n-butyllithium, n-hexane, and carbon dioxide gas used in step A2 is 1 mmol: 20 mL: 4 mmol: 1.6 mL: 90 mL.

[0046] The ratio of cobalt acetate, modified ligand, modified additive, DMF, deionized water and modified filler in step A3 is 4 mmol: 6 mmol: 0.2 g: 15 mL: 15 mL: 1 g.

[0047] The modified additive is prepared by the following steps:

[0048] Step B1: Tetramethylcyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetra(3,3,3-trifluoropropyl)cyclotetrasiloxane, tetramethylammonium hydroxide and dimethyl sulfoxide were mixed and purged with nitrogen. The mixture was reacted at 150 r / min and 85 °C for 7 h. Then hexamethyldisiloxane was added and the reaction was continued for 4 h. The temperature was raised to 110 °C and the reaction was continued for 2 h to obtain the modified polysiloxane.

[0049] Step B2: Mix 5-hydroxyisophthalic acid and tetrahydrofuran evenly, purge with argon gas, stir at 200 r / min and 5°C, add triethylamine and acryloyl chloride, heat to 20°C and react for 10 h, then add dilute hydrochloric acid to pH 3 to obtain the modifier. Mix the modifier, modified polysiloxane, chloroplatinic acid and DMF evenly, purge with nitrogen gas, and react at 150 r / min and 80°C for 7 h to obtain the modified additive.

[0050] The ratio of tetramethylcyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetra(3,3,3-trifluoropropyl)cyclotetrasiloxane, tetramethylammonium hydroxide, hexamethyldisiloxane and dimethyl sulfoxide in step B1 is 0.2 mol: 1 mol: 1.5 mol: 1 mol: 5 mL.

[0051] In step B2, the molar ratio of 5-hydroxyisophthalic acid, triethylamine, and acryloyl chloride is 1:3:1.1, the molar ratio of the Si-H bonds on the modifier and the modified polysiloxane is 1:1, and the amount of chloroplatinic acid is 30 ppm of the sum of the mass of the modifier and the modified polysiloxane.

[0052] The modified filler is prepared by the following steps:

[0053] Graphene oxide, 4-aminopyridine, dicyclohexylcarbodiimide, and DMF were mixed and purged with nitrogen. The mixture was reacted for 4 hours at a speed of 500 r / min and a temperature of 25 °C to obtain pretreated graphene. The pretreated graphene was dispersed in deionized water, and ammonia was added to adjust the pH to 10. The mixture was stirred and hydrazine hydrate was added at a speed of 300 r / min and a temperature of 95 °C. The mixture was then reacted for 13 hours to obtain the modified filler.

[0054] The molar ratio of carboxyl groups, 4-aminopyridine, and dicyclohexylcarbodiimide on the graphene oxide is 1:1:1.1, and the amounts of pretreated graphene, deionized water, and hydrazine hydrate are 100 mg: 200 mL: 1 mL.

[0055] Example 3: A method for preparing a fast-charging, high-capacity artificial graphite anode material, specifically including the following steps:

[0056] Step A1: Mix p-dibromobenzene and tetrahydrofuran evenly, purge with argon gas, add n-butyllithium and n-hexane at a rotation speed of 200 r / min and a temperature of -78℃, and react for 3 h. Then add tetrachlorosilane, raise the temperature to 0℃, and react for 3 h. Raise the temperature to 25℃ and continue the reaction for 15 h to obtain the intermediate.

[0057] Step A2: Mix the intermediate and tetrahydrofuran evenly, under argon protection, at a rotation speed of 150 r / min and a temperature of -78℃, add n-butyllithium and n-hexane, and react for 3 h. Then, introduce carbon dioxide gas and continue the reaction for 3 h. After quenching with saturated ammonium chloride aqueous solution, add hydrochloric acid aqueous solution until the pH value is 3 to obtain the modified ligand.

[0058] Step A3: Mix cobalt acetate, modified ligand, modified additive and DMF evenly, sonicate at a frequency of 30kHz and a temperature of 30℃, add deionized water and modified filler, sonicate for 30min, heat to 170℃ and react for 25h, centrifuge to remove supernatant and dry to obtain fast-charging high-capacity artificial graphite anode material.

[0059] The ratio of p-dibromobenzene, tetrahydrofuran, p-dibromobenzene, n-hexane, and tetrachlorosilane used in step A1 is 4 mmol: 20 mL: 4 mmol: 1.6 mL: 1 mmol.

[0060] The ratio of the intermediate, tetrahydrofuran, n-butyllithium, n-hexane, and carbon dioxide gas used in step A2 is 1 mmol: 20 mL: 4 mmol: 1.6 mL: 90 mL.

[0061] The ratio of cobalt acetate, modified ligand, modified additive, DMF, deionized water and modified filler in step A3 is 4 mmol: 6 mmol: 0.2 g: 15 mL: 15 mL: 1 g.

[0062] The modified additive is prepared by the following steps:

[0063] Step B1: Tetramethylcyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetra(3,3,3-trifluoropropyl)cyclotetrasiloxane, tetramethylammonium hydroxide and dimethyl sulfoxide were mixed and purged with nitrogen. The mixture was reacted for 8 hours at a speed of 200 r / min and a temperature of 90 °C. Then hexamethyldisiloxane was added and the reaction was continued for 5 hours. The temperature was then raised to 110 °C and the reaction was continued for 3 hours to obtain the modified polysiloxane.

[0064] Step B2: Mix 5-hydroxyisophthalic acid and tetrahydrofuran evenly, purge with argon gas, stir at 300 r / min and 5°C, add triethylamine and acryloyl chloride, heat to 25°C and react for 12 h, then add dilute hydrochloric acid to pH 3 to obtain the modifier. Mix the modifier, modified polysiloxane, chloroplatinic acid and DMF evenly, purge with nitrogen gas, and react at 200 r / min and 85°C for 8 h to obtain the modified additive.

[0065] The ratio of tetramethylcyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetra(3,3,3-trifluoropropyl)cyclotetrasiloxane, tetramethylammonium hydroxide, hexamethyldisiloxane and dimethyl sulfoxide in step B1 is 0.2 mol: 1 mol: 1.5 mol: 1 mol: 5 mL.

[0066] In step B2, the molar ratio of 5-hydroxyisophthalic acid, triethylamine, and acryloyl chloride is 1:3:1.1, the molar ratio of the Si-H bonds on the modifier and the modified polysiloxane is 1:1, and the amount of chloroplatinic acid is 30 ppm of the sum of the mass of the modifier and the modified polysiloxane.

[0067] The modified filler is prepared by the following steps:

[0068] Graphene oxide, 4-aminopyridine, dicyclohexylcarbodiimide, and DMF were mixed and purged with nitrogen. The mixture was reacted for 5 hours at a speed of 500 r / min and a temperature of 30 °C to obtain pretreated graphene. The pretreated graphene was dispersed in deionized water, and ammonia was added to adjust the pH to 10. The mixture was stirred and hydrazine hydrate was added at a speed of 300 r / min and a temperature of 98 °C. The mixture was then reacted for 15 hours to obtain the modified filler.

[0069] The molar ratio of carboxyl groups, 4-aminopyridine, and dicyclohexylcarbodiimide on the graphene oxide is 1:1:1.1, and the amounts of pretreated graphene, deionized water, and hydrazine hydrate are 100 mg: 200 mL: 1 mL.

[0070] Comparative Example 1: In this comparative example, octamethylcyclotetrasiloxane was used instead of 2,4,6,8-tetramethyl-2,4,6,8-tetra(3,3,3-trifluoropropyl)cyclotetrasiloxane, while the other steps were the same.

[0071] Comparative Example 2: This comparative example did not include any modifying additives compared to Example 1, but the remaining steps were the same.

[0072] Comparative Example 3: This comparative example uses graphene oxide instead of pretreated graphene, while the other steps are the same as in Example 1.

[0073] The negative electrode materials obtained in Examples 1-3 and Comparative Examples 1-3, PVDF, Super-P and N-methylpyrrolidone were mixed in a mass ratio of 95:5:5:150 to prepare a negative electrode slurry. The negative electrode slurry was coated on copper foil, dried, rolled and sliced ​​to obtain a negative electrode sheet. A battery sample was made by using a lithium sheet as the positive electrode, a Celgard 2400 separator, an electrolyte (1M LiPF6 / EC+EMC+DMC volume ratio 1:1:1), the negative electrode sheet and a button cell casing.

[0074] Rate performance testing was conducted with a charge / discharge voltage range of 2.5-4.2V and a temperature of 25℃. The batteries were charged at 1.0C and 3.0C respectively, and discharged at 1.0C. The constant current ratio of the battery under different charging modes was measured, and the test results are shown in Table 1 below.

[0075] The capacity retention rate was tested by performing 500 charge-discharge cycles at a 2C / 2C charge-discharge rate and a voltage range of 2.8-4.2V. The test results are shown in Table 1 below.

[0076] Table 1

[0077]

[0078] As shown in Table 1, this application has a very good charging speed and the battery capacity is minimally damaged after multiple charge and discharge cycles.

[0079] 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 method for preparing a fast-charging high-capacity artificial graphite negative electrode material, characterized by comprising the following steps: Specifically comprising the following steps: ​ Step A1: the p-dibromobenzene and tetrahydrofuran are mixed uniformly, argon is introduced, n-butyllithium and n-hexane are added, after reaction, tetrachlorosilane is added, the temperature is increased and the reaction is continued, to obtain an intermediate; Step A2: the intermediate and tetrahydrofuran are mixed uniformly, argon is introduced, n-butyllithium and n-hexane are added, after reaction, carbon dioxide gas is introduced, the reaction is continued, saturated ammonium chloride aqueous solution is added to quench, hydrochloric acid aqueous solution is added to pH 3, to obtain a modified ligand; Step A3: the cobalt acetate, the modified ligand, the modified additive and DMF are mixed and ultrasonicated, deionized water and modified filler are added, after ultrasonic treatment, the temperature is increased to 160-170℃, the reaction is carried out for 20-25h, the supernatant is removed by centrifugation, and drying treatment is carried out, to obtain a fast-charging high-capacity artificial graphite negative electrode material; The modified additive is prepared by the following steps: Step B1: the tetramethylcyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetrakis(3,3,3-trifluoropropyl)cyclotetrasiloxane, tetramethylammonium hydroxide and dimethyl sulfoxide are mixed, nitrogen is introduced, the reaction is carried out, hexamethyldisiloxane is added, the reaction is continued, to obtain a modified polysiloxane; Step B2: the 5-hydroxyisophthalic acid and tetrahydrofuran are mixed uniformly, argon is introduced, stirring is carried out, triethylamine and acryloyl chloride are added, after reaction, dilute hydrochloric acid is added to pH 2-3, to obtain a modifier, the modifier, the modified polysiloxane, chloroplatinic acid and DMF are mixed uniformly, nitrogen is introduced, the reaction is carried out, to obtain a modified additive; The modified filler is prepared by the following steps: The graphene oxide, 4-aminopyridine, dicyclohexyl carbodiimide and DMF are mixed, nitrogen is introduced, the reaction is carried out, to obtain pretreated graphene, the pretreated graphene is dispersed in deionized water, ammonia water is added to adjust pH to 10, stirring is carried out, hydrazine hydrate is added, the reaction is carried out, to obtain a modified filler.

2. The method of claim 1, wherein the method is characterized by: The p-dibromobenzene, tetrahydrofuran, p-dibromobenzene, n-hexane and tetrachlorosilane in step A1 are used in a ratio of 4mmol:20mL:4mmol:1.6mL:1mmol.

3. The method of claim 1, wherein the method is characterized by: The intermediate, tetrahydrofuran, n-butyllithium, n-hexane and carbon dioxide gas in step A2 are used in a ratio of 1mmol:20mL:4mmol:1.6mL:90mL.

4. The method of claim 1, wherein the method is characterized by: The cobalt acetate, the modified ligand, the modified additive, DMF, deionized water and the modified filler in step A3 are used in a ratio of 4mmol:6mmol:0.2g:15mL:15mL:1g.

5. The method of claim 1, wherein the method is characterized by: The tetramethylcyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetrakis(3,3,3-trifluoropropyl)cyclotetrasiloxane, tetramethylammonium hydroxide, hexamethyldisiloxane and dimethyl sulfoxide in step B1 are used in a ratio of 0.2mol:1mol:1.5mol:1mol:5mL.

6. The method of producing a fast-charging high-capacity artificial graphite negative material according to claim 1, characterized by: The 5-hydroxyisophthalic acid, triethylamine and acryloyl chloride in step B2 are used in a molar ratio of 1:3:1.1, and the molar ratio of the modifier to the Si-H bond on the modified polysiloxane is 1:

1.

7. The method of producing a fast-charging high-capacity artificial graphite negative material according to claim 1, characterized by: The molar ratio of carboxyl group on graphene oxide, 4-aminopyridine and dicyclohexyl carbodiimide is 1:1:1.1, and the amount of pretreated graphene, deionized water and hydrazine hydrate is 100 mg:200 mL:1 mL. 8.A high-capacity artificial graphite negative electrode material for fast charging, characterized by comprising: Prepared according to the preparation method of any one of claims 1-7.

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