Current collector with high structural stability and preparation method thereof

Abstract

The invention discloses a current collector with high structural stability and a preparation method thereof, and relates to the technical field of batteries, a copper foil is taken, cleaned and blow-dried, and the middle areas of the two sides of the copper foil are thinned to obtain an H-shaped copper foil, namely a metal foil; taking an organic solution, uniformly coating the thinned part of the middle area of the H-shaped copper foil with the organic solution, drying, curing and cooling to obtain an organic layer; copper is deposited on the organic layer through magnetron sputtering, then electro-deposition liquid is added for electro-deposition, vacuum drying is carried out, and the metal layer is obtained. A current collector with high structural stability is prepared, middle layers on the two sides of a copper foil are thinned to obtain an H-shaped copper foil, and an organic layer and a metal layer are constructed on the H-shaped copper foil, so that on one hand, the contact area between the organic layer and the metal foil and between the organic layer and the metal layer is increased, and the interface bonding strength and the structural stability are improved through a mechanical interlocking effect; on the other hand, the current collector thickness is reduced, the battery energy density is improved, and the battery performance is improved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a current collector with high structural stability and its preparation method. Background Technology

[0002] Current collectors, used in electrochemical devices, are one of the core components, playing the roles of collecting and conducting current and loading active materials. Current collectors are required to have excellent conductivity, chemical and electrochemical stability, and structural stability. In particular, structural stability directly affects battery performance. Traditional current collectors are composed of a single metal foil, while composite current collectors are composed of a "metal-organic layer-metal". Batteries made with this composite current collector have higher energy density, safety, and cycle life than those made with traditional current collectors. How to further improve the performance of composite current collectors is a new challenge in the new era.

[0003] To address the above problems, this invention provides a current collector with high structural stability and its preparation method. Summary of the Invention

[0004] The purpose of this invention is to provide a current collector with high structural stability and its preparation method, so as to solve the problems raised in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: The current collector comprises a metal foil, an organic layer, and a metal layer. The metal foil is an H-shaped copper foil prepared by thinning the middle area on both sides of a copper foil. An organic layer and a metal layer are sequentially placed on the metal foil. The thickness of the copper foil is 6-12µm, the thickness of the organic layer is 1-3µm, and the thickness of the metal layer is 0.5-2µm.

[0006] A more optimized step is: take copper foil, clean it, dry it, and thin the middle area on both sides of the copper foil to obtain an H-shaped copper foil, i.e., a metal foil. Step 2: Take an organic solution and apply it evenly to the thinned area in the middle of the H-shaped copper foil. Dry, cure, and cool to obtain an organic layer. Step 3: First, deposit copper on the organic layer by magnetron sputtering, then add electrodeposition solution for electrodeposition, and vacuum dry to obtain the metal layer; The organic solution is prepared by taking modified hexagonal boron nitride dispersion and polyimide solution, mixing them evenly to obtain the organic solution.

[0007] A more optimized method for preparing the modified hexagonal boron nitride dispersion is as follows: Take modified hexagonal boron nitride, sieve it to obtain modified hexagonal boron nitride A and modified hexagonal boron nitride B, take modified hexagonal boron nitride A and modified hexagonal boron nitride B, mix them evenly to obtain a modified hexagonal boron nitride mixture; add the modified hexagonal boron nitride mixture to N,N-dimethylacetamide, sonicate for 1-2 hours to obtain the modified hexagonal boron nitride dispersion.

[0008] A more optimized method for preparing the polyimide solution is as follows: Under a nitrogen atmosphere, polyurea oligomers are added to N,N-dimethylacetamide and stirred until completely dissolved at 70-80℃. Then, 4,4'-biphenyl dianhydride is added and the reaction is carried out for 0.5-1.5 hours. Next, 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and N,N-dimethylacetamide are added and stirred until completely dissolved. The reaction is carried out for 22-26 hours at 70-80℃, and then cooled to obtain the polyimide solution.

[0009] The more optimized modified hexagonal boron nitride A has a particle size of 50-100 nm, the modified hexagonal boron nitride B has a particle size of 200-400 nm, and the mass ratio of modified hexagonal boron nitride A to modified hexagonal boron nitride B is (0.8-1.2):(0.8-1.2).

[0010] A more optimized method for preparing modified hexagonal boron nitride is as follows: Add hexagonal boron nitride to an aqueous sodium hydroxide solution, add grinding balls, and ball mill at 200-300 rpm for 22-26 hours. Wash, vacuum dry, add to anhydrous toluene, sonicate for 1-2 hours, add 3-glycidyl etheroxypropyltrimethoxysilane, purge with nitrogen, and react at 80-85℃ for 22-26 hours. Wash, vacuum dry, add to N,N-dimethylformamide, add p-aminobenzoic acid and triethylamine, purge with nitrogen, and react at 90-100℃ for 10-14 hours. Wash, vacuum dry to obtain modified hexagonal boron nitride.

[0011] A more optimized method for preparing polyurea oligomers is as follows: take polyetheramine, pass carbon dioxide through it, and react for 10-14 hours under the conditions of pressure 6-10 MPa, temperature 150-200℃, and rotation speed 200-300 rpm. After cooling and removing impurities, vacuum dry at a temperature of 70-80℃ for 22-26 hours to obtain polyurea oligomers.

[0012] A more optimized electrodeposition solution, using deionized water as a solvent, includes the following components, listed in concentration: 40-60 g / L copper sulfate pentahydrate, 80-120 g / L concentrated sulfuric acid, 50-100 mg / L sodium chloride, 0.4-0.5 g / L polyethylene glycol, 0.4-0.6 g / L dodecyltrimethylammonium bromide, 0.1-0.2 g / L benzotriazole, and 0.05-0.2 g / L 2-aminobenzothiazole.

[0013] A more optimized method for preparing the electrodeposition solution is as follows: Add copper sulfate pentahydrate to deionized water and stir until completely dissolved. Add concentrated sulfuric acid, sodium chloride, polyethylene glycol, dodecyltrimethylammonium bromide, benzotriazole, and 2-aminobenzothiazole, mix evenly, make up to a certain volume, let stand, and filter to obtain the electrodeposition solution.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. To prepare a current collector with high structural stability, the middle layer on both sides of the copper foil is thinned to obtain an H-shaped copper foil. An organic layer and a metal layer are then constructed on the H-shaped copper foil. On the one hand, this increases the contact area between the organic layer and the metal foil and metal layer, and improves the interfacial bonding strength through the mechanical interlocking effect, thereby improving structural stability. On the other hand, it reduces the thickness of the current collector, increases the energy density of the battery, and improves battery performance.

[0015] 2. Preparation of modified hexagonal boron nitride mixture: During ball milling, the shear force generated by the friction between the grinding balls and the hexagonal boron nitride causes the interlayers of hexagonal boron nitride to peel off, exposing it to sodium hydroxide solution. Edge hydroxylation introduces hydroxyl groups, and the mixture reacts with silanols formed by the hydrolysis of 3-glycidoxypropyltrimethoxysilane, introducing epoxy groups. Under the catalysis of triethylamine, a ring-opening reaction occurs with the amino group of p-aminobenzoic acid, introducing carboxyl groups, thus obtaining modified hexagonal boron nitride and improving its dispersion in the organic layer. The interfacial bonding strength between the organic layer and the polyimide matrix was determined; sieving yielded modified hexagonal boron nitride A and modified hexagonal boron nitride B, with particle sizes of 50-100 nm for modified hexagonal boron nitride A and 200-400 nm for modified hexagonal boron nitride B. On the one hand, the combination of smaller and larger particle sizes of modified hexagonal boron nitride constructs a multi-sized rough surface, improving the interfacial bonding strength between the organic layer and the metal foil, and between the metal layers, through mechanical interlocking; on the other hand, by dispersing in the organic layer, it suppresses the generation of microcracks and improves structural stability.

[0016] 3. Under high temperature and high pressure conditions, the amino group of polyetheramine reacts with carbon dioxide to form urea bonds, resulting in polyurea oligomers. The long-chain polyether structure of polyetheramine improves the flexibility of the organic layer, buffers the volume expansion and contraction of the active material during charging and discharging, and improves structural stability. The amino group of the polyurea oligomer reacts with 4,4'-biphenyl ether dianhydride to form an amide acid prepolymer. 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane is added for chain extension to form a polyimide solution. The introduction of hydroxyl and hexafluoropropane groups improves the interfacial bonding strength between the polyimide and the metal foil and metal layer, thereby improving structural stability.

[0017] 4. A metal layer is prepared by magnetron sputtering a copper layer onto the organic layer to improve surface conductivity and enhance electrodeposition uniformity. Polyethylene glycol is used as a leveling agent, dodecyltrimethylammonium bromide as a grain refiner and surfactant, and benzotriazole and 2-aminobenzothiazole as corrosion inhibitors. Three-dimensional micro / nano porous copper is electrodeposited onto the copper layer. On one hand, the numerous pores and large space within the three-dimensional micro / nano porous structure buffer the volume expansion stress during battery charging and discharging, improving structural stability. On the other hand, it reduces current density, suppresses lithium dendrite formation, and improves structural stability, safety, and battery performance. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the high structural stability current collector of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0020] The sources and types of substances involved in this invention are not particularly limited, and exemplary examples include: The hexagonal boron nitride, with the product number B693419, is supplied by Shanghai Maclean Biochemical Technology Co., Ltd. The grinding balls are available in 3mm and 5mm sizes, made of 304 stainless steel, and supplied by Taian Haoxin Steel Ball Co., Ltd. 3-Glycidyl etheroxypropyltrimethoxysilane, catalog number 2530-83-8, is supplied by Hubei Rishengchang New Material Technology Co., Ltd. N,N-dimethylformamide, catalog number 044, is supplied by Shandong Zhengxing New Materials Co., Ltd. Para-aminobenzoic acid, catalog number 767465, is supplied by Shanghai Maclean Biochemical Technology Co., Ltd. Triethylamine, catalog number 100, was supplied by Shandong Yihong Chemical Co., Ltd. N,N-Dimethylacetamide, catalog number N807173, is supplied by Shanghai Maclean Biochemical Technology Co., Ltd. The polyetheramine, with catalog number P815988, was provided by Shanghai Maclean Biochemical Technology Co., Ltd. The product number for 4,4'-biphenyl ether dianhydride is 9407013, and it is supplied by Forsmann Technology (Beijing) Co., Ltd. 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, with catalog number 83558-87-6, is supplied by Tianjin Zhongtai Materials Technology Co., Ltd. Copper sulfate pentahydrate, catalog number S24261, is supplied by Shanghai Yuanye Biotechnology Co., Ltd. The polyethylene glycol, with catalog number P815609, was supplied by Shanghai Maclean Biochemical Technology Co., Ltd. The product number of dodecyltrimethylammonium bromide is S15009, and it is provided by Shanghai Yuanye Biotechnology Co., Ltd. The product code for benzotriazole is H689916, and it is supplied by Shanghai Maclean Biochemical Technology Co., Ltd. 2-Aminobenzothiazole, catalog number XHL0810, was supplied by Hubei Xinhongli Chemical Co., Ltd. The lithium iron phosphate product number is JS2250, supplied by Hubei Jusheng Technology Co., Ltd. The polyvinylidene fluoride (PVDF) has the product number HC3637 and is supplied by Tianmen Hengchang Chemical Co., Ltd. The carbon nanotubes, part number 0601003, are supplied by Forsmann Technology (Beijing) Co., Ltd. The carbon black, with product number YK1036, was supplied by Hubei Yongkuo Technology Co., Ltd. The graphite, with catalog number S26651, was provided by Shanghai Yuanye Biotechnology Co., Ltd. The hard carbon material, with part number LN0001, is supplied by Shanghai Huiping New Energy Co., Ltd. The styrene-butadiene rubber, with part number 12979, was supplied by Jiangsu Congzhong Chemical Co., Ltd. Sodium carboxymethyl cellulose, catalog number S52911, is supplied by Shanghai Yuanye Biotechnology Co., Ltd. Ethylene carbonate, catalog number 96-49-1, is supplied by Zhende Chemical Technology (Shanghai) Co., Ltd. Diethyl carbonate, catalog number CG57, is supplied by Shandong Zhengxing New Materials Co., Ltd. The lithium hexafluorophosphate, with catalog number 21324-40-3, is supplied by Chongqing Ruiya Biotechnology Co., Ltd.

[0021] Example 1: A method for preparing a current collector with high structural stability; Step 1: Preparation of modified hexagonal boron nitride dispersion S1: Take 3g of hexagonal boron nitride and add it to 60mL of 2mol / L sodium hydroxide aqueous solution. Add 210g of grinding balls and ball mill at 200rpm for 22h. Wash, vacuum dry, add to 150mL of anhydrous toluene, sonicate for 1h, add 4.5g of 3-glycidyl etheroxypropyltrimethoxysilane, purge with nitrogen, and react at 80℃ for 24h. Wash, vacuum dry, add to 90mL of N,N-dimethylformamide, add 2.5g of p-aminobenzoic acid and 2mL of triethylamine, purge with nitrogen, and react at 90℃ for 12h. Wash, vacuum dry to obtain modified hexagonal boron nitride. S2: Take modified hexagonal boron nitride, sieve it to obtain modified hexagonal boron nitride A and modified hexagonal boron nitride B. The particle size of modified hexagonal boron nitride A is 50-100nm and the particle size of modified hexagonal boron nitride B is 200-400nm. Take modified hexagonal boron nitride A and modified hexagonal boron nitride B at a mass ratio of 0.8:1.2, mix them evenly to obtain a modified hexagonal boron nitride mixture; take 1g of the modified hexagonal boron nitride mixture and add it to 50mL of N,N-dimethylacetamide, sonicate for 1h to obtain a modified hexagonal boron nitride dispersion; Step 2: Preparation of the organic layer S1: Take 140g of polyetheramine, pass carbon dioxide through it, and react for 10h under the conditions of 6MPa pressure, 180℃ temperature and 200rpm rotation speed. After cooling and removing impurities, dry under vacuum at 70℃ for 22h to obtain polyurea oligomer. S2: Under a nitrogen atmosphere, 20g of polyurea oligomer was added to 150mL of N,N-dimethylacetamide. The mixture was stirred until completely dissolved at 70℃. 29.42g of 4,4'-biphenyl dianhydride was added, and the reaction was allowed to proceed for 0.5h. Then, 21.68g of 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and 100mL of N,N-dimethylacetamide were added, and the mixture was stirred until completely dissolved. The reaction was allowed to proceed for 22h at 70℃. After cooling, a polyimide solution was obtained. The modified hexagonal boron nitride dispersion and the polyimide solution were mixed thoroughly to obtain an organic solution. S3: Take copper foil with a thickness of 10µm, clean it, blow it dry, and thin the middle area on both sides of the copper foil to obtain an H-shaped copper foil; take an organic solution, coat it evenly on the thinned middle area of ​​the H-shaped copper foil, dry it, cure it, and cool it to obtain an organic layer with a thickness of 2µm. Step 2: Preparation of current collectors with high structural stability First, copper is deposited on the organic layer by magnetron sputtering, and then electrodeposition is performed on its surface. The anode sample is 1 cm².2 Take 50g of copper sulfate pentahydrate and add it to 800mL of deionized water. Stir until completely dissolved. Add 55mL of concentrated sulfuric acid, 0.08g of sodium chloride, 0.45g of polyethylene glycol, 0.5g of dodecyltrimethylammonium bromide, 0.15g of benzotriazole, and 0.1g of 2-aminobenzothiazole. Mix well and bring the volume to 1L. Let stand, filter, and obtain the electrodeposition solution. Apply the solution at a current density of 2A / cm². 2 At a deposition temperature of 25°C, deposition was carried out for 15 seconds, followed by vacuum drying to obtain a metal layer with a thickness of 1µm.

[0022] Example 2: A method for preparing a current collector with high structural stability; Step 1: Preparation of modified hexagonal boron nitride dispersion S1: Take 3g of hexagonal boron nitride and add it to 60mL of 2mol / L sodium hydroxide aqueous solution. Add 210g of grinding balls and ball mill at 250rpm for 24h. Wash, vacuum dry, add to 150mL of anhydrous toluene, sonicate for 1.5h, add 4.5g of 3-glycidyl etheroxypropyltrimethoxysilane, purge with nitrogen, react at 83℃ for 24h, wash, vacuum dry, add to 90mL of N,N-dimethylformamide, add 2.5g of p-aminobenzoic acid and 2mL of triethylamine, purge with nitrogen, react at 95℃ for 12h, wash, vacuum dry to obtain modified hexagonal boron nitride; S2: Take modified hexagonal boron nitride, sieve it to obtain modified hexagonal boron nitride A and modified hexagonal boron nitride B. The particle size of modified hexagonal boron nitride A is 50-100nm and the particle size of modified hexagonal boron nitride B is 200-400nm. Take modified hexagonal boron nitride A and modified hexagonal boron nitride B at a mass ratio of 1:1, mix them evenly to obtain a modified hexagonal boron nitride mixture; take 2g of the modified hexagonal boron nitride mixture and add it to 50mL of N,N-dimethylacetamide, sonicate for 1.5h to obtain a modified hexagonal boron nitride dispersion; Step 2: Preparation of the organic layer S1: Take 140g of polyetheramine, pass carbon dioxide through it, and react for 12h under the conditions of 8MPa pressure, 180℃ temperature and 200rpm rotation speed. After cooling and removing impurities, dry under vacuum at 75℃ for 24h to obtain polyurea oligomer. S2: Under a nitrogen atmosphere, 20g of polyurea oligomer was added to 150mL of N,N-dimethylacetamide. The mixture was stirred until completely dissolved at 70℃. 29.42g of 4,4'-biphenyl dianhydride was added, and the reaction was allowed to proceed for 0.5h. Then, 21.68g of 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and 100mL of N,N-dimethylacetamide were added, and the mixture was stirred until completely dissolved. The reaction was allowed to proceed for 22h at 70℃. After cooling, a polyimide solution was obtained. The modified hexagonal boron nitride dispersion and the polyimide solution were mixed thoroughly to obtain an organic solution. S3: Take copper foil with a thickness of 10µm, clean it, blow it dry, and thin the middle area on both sides of the copper foil to obtain an H-shaped copper foil; take an organic solution, coat it evenly on the thinned middle area of ​​the H-shaped copper foil, dry it, cure it, and cool it to obtain an organic layer with a thickness of 2µm. Step 2: Preparation of current collectors with high structural stability First, copper is deposited on the organic layer by magnetron sputtering, and then electrodeposition is performed on its surface. The anode sample is 1 cm². 2 For copper sheets, add 50g of copper sulfate pentahydrate to 800mL of deionized water and stir until completely dissolved. Add 55mL of concentrated sulfuric acid, 0.08g of sodium chloride, 0.45g of polyethylene glycol, 0.5g of dodecyltrimethylammonium bromide, 0.15g of benzotriazole, and 0.1g of 2-aminobenzothiazole. Mix well and bring the volume to 1L. Let stand, filter, and obtain the electrodeposition solution. At a current density of 2.5A / cm², [the solution is prepared]. 2 At a deposition temperature of 25°C, deposition was carried out for 15 seconds, followed by vacuum drying to obtain a metal layer with a thickness of 1µm.

[0023] Example 3: A method for preparing a current collector with high structural stability; Step 1: Preparation of modified hexagonal boron nitride dispersion S1: Take 3g of hexagonal boron nitride and add it to 60mL of 2mol / L sodium hydroxide aqueous solution. Add 210g of grinding balls and ball mill for 26h at 300rpm. Wash, vacuum dry, add to 150mL of anhydrous toluene, sonicate for 2h, add 4.5g of 3-glycidyl etheroxypropyltrimethoxysilane, purge with nitrogen, react at 85℃ for 24h, wash, vacuum dry, add to 90mL of N,N-dimethylformamide, add 2.5g of p-aminobenzoic acid and 2mL of triethylamine, purge with nitrogen, react at 100℃ for 12h, wash, vacuum dry to obtain modified hexagonal boron nitride; S2: Take modified hexagonal boron nitride, sieve it to obtain modified hexagonal boron nitride A and modified hexagonal boron nitride B. The particle size of modified hexagonal boron nitride A is 50-100nm and the particle size of modified hexagonal boron nitride B is 200-400nm. Take modified hexagonal boron nitride A and modified hexagonal boron nitride B at a mass ratio of 1.2:0.8, mix them evenly to obtain a modified hexagonal boron nitride mixture; take 3g of the modified hexagonal boron nitride mixture and add it to 50mL of N,N-dimethylacetamide, sonicate for 2h to obtain a modified hexagonal boron nitride dispersion; Step 2: Preparation of the organic layer S1: Take 140g of polyetheramine, pass carbon dioxide through it, and react for 14h under the conditions of 10MPa pressure, 180℃ temperature and 200rpm rotation speed. After cooling and removing impurities, dry under vacuum at 80℃ for 26h to obtain polyurea oligomer. S2: Under a nitrogen atmosphere, 20g of polyurea oligomer was added to 150mL of N,N-dimethylacetamide. The mixture was stirred until completely dissolved at 70℃. 29.42g of 4,4'-biphenyl dianhydride was added, and the reaction was allowed to proceed for 0.5h. Then, 21.68g of 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and 100mL of N,N-dimethylacetamide were added, and the mixture was stirred until completely dissolved. The reaction was allowed to proceed for 22h at 70℃. After cooling, a polyimide solution was obtained. The modified hexagonal boron nitride dispersion and the polyimide solution were mixed thoroughly to obtain an organic solution. S3: Take copper foil with a thickness of 10µm, clean it, blow it dry, and thin the middle area on both sides of the copper foil to obtain an H-shaped copper foil; take an organic solution, coat it evenly on the thinned middle area of ​​the H-shaped copper foil, dry it, cure it, and cool it to obtain an organic layer with a thickness of 2µm. Step 2: Preparation of current collectors with high structural stability First, copper is deposited on the organic layer by magnetron sputtering, and then electrodeposition is performed on its surface. The anode sample is 1 cm². 2 Take 50g of copper sulfate pentahydrate and add it to 800mL of deionized water. Stir until completely dissolved. Add 55mL of concentrated sulfuric acid, 0.08g of sodium chloride, 0.45g of polyethylene glycol, 0.5g of dodecyltrimethylammonium bromide, 0.15g of benzotriazole, and 0.1g of 2-aminobenzothiazole. Mix well and bring the volume to 1L. Let stand, filter, and obtain the electrodeposition solution. At a current density of 3A / cm², [the solution is prepared]. 2 At a deposition temperature of 25°C, deposition was carried out for 15 seconds, followed by vacuum drying to obtain a metal layer with a thickness of 1µm.

[0024] Comparative Example 1: 3-glycidoxypropyltrimethoxysilane was not added; otherwise, refer to Example 2. Step 1: Preparation of modified hexagonal boron nitride dispersion S1: Take 3g of hexagonal boron nitride and add it to 60mL of 2mol / L sodium hydroxide aqueous solution. Add 210g of grinding balls and ball mill for 24h at 250rpm. Wash, vacuum dry, add to 150mL of anhydrous toluene, sonicate for 1.5h, introduce nitrogen gas, react at 83℃ for 24h, wash, vacuum dry, add to 90mL of N,N-dimethylformamide, add 2.5g of p-aminobenzoic acid and 2mL of triethylamine, introduce nitrogen gas, react at 95℃ for 12h, wash, vacuum dry, and obtain modified hexagonal boron nitride; S2: Take modified hexagonal boron nitride, sieve it to obtain modified hexagonal boron nitride A and modified hexagonal boron nitride B. The particle size of modified hexagonal boron nitride A is 50-100nm and the particle size of modified hexagonal boron nitride B is 200-400nm. Take modified hexagonal boron nitride A and modified hexagonal boron nitride B at a mass ratio of 1:1, mix them evenly to obtain a modified hexagonal boron nitride mixture; take 2g of the modified hexagonal boron nitride mixture and add it to 50mL of N,N-dimethylacetamide, sonicate for 1.5h to obtain a modified hexagonal boron nitride dispersion; Step 2: Preparation of the organic layer S1: Take 140g of polyetheramine, pass carbon dioxide through it, and react for 12h under the conditions of 8MPa pressure, 180℃ temperature and 200rpm rotation speed. After cooling and removing impurities, dry under vacuum at 75℃ for 24h to obtain polyurea oligomer. S2: Under a nitrogen atmosphere, 20g of polyurea oligomer was added to 150mL of N,N-dimethylacetamide. The mixture was stirred until completely dissolved at 70℃. 29.42g of 4,4'-biphenyl dianhydride was added, and the reaction was allowed to proceed for 0.5h. Then, 21.68g of 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and 100mL of N,N-dimethylacetamide were added, and the mixture was stirred until completely dissolved. The reaction was allowed to proceed for 22h at 70℃. After cooling, a polyimide solution was obtained. The modified hexagonal boron nitride dispersion and the polyimide solution were mixed thoroughly to obtain an organic solution. S3: Take copper foil with a thickness of 10µm, clean it, blow it dry, and thin the middle area on both sides of the copper foil to obtain an H-shaped copper foil; take an organic solution, coat it evenly on the thinned middle area of ​​the H-shaped copper foil, dry it, cure it, and cool it to obtain an organic layer with a thickness of 2µm. Step 2: Preparation of current collectors with high structural stability First, copper is deposited on the organic layer by magnetron sputtering, and then electrodeposition is performed on its surface. The anode sample is 1 cm². 2For copper sheets, add 50g of copper sulfate pentahydrate to 800mL of deionized water and stir until completely dissolved. Add 55mL of concentrated sulfuric acid, 0.08g of sodium chloride, 0.45g of polyethylene glycol, 0.5g of dodecyltrimethylammonium bromide, 0.15g of benzotriazole, and 0.1g of 2-aminobenzothiazole. Mix well and bring the volume to 1L. Let stand, filter, and obtain the electrodeposition solution. At a current density of 2.5A / cm², [the solution is prepared]. 2 At a deposition temperature of 25°C, deposition was carried out for 15 seconds, followed by vacuum drying to obtain a metal layer with a thickness of 1µm.

[0025] Comparative Example 2: No sieving was performed; all other aspects are the same as in Example 2. Step 1: Preparation of modified hexagonal boron nitride dispersion S1: Take 3g of hexagonal boron nitride and add it to 60mL of 2mol / L sodium hydroxide aqueous solution. Add 210g of grinding balls and ball mill at 250rpm for 24h. Wash, vacuum dry, add to 150mL of anhydrous toluene, sonicate for 1.5h, add 4.5g of 3-glycidyl etheroxypropyltrimethoxysilane, purge with nitrogen, react at 83℃ for 24h, wash, vacuum dry, add to 90mL of N,N-dimethylformamide, add 2.5g of p-aminobenzoic acid and 2mL of triethylamine, purge with nitrogen, react at 95℃ for 12h, wash, vacuum dry to obtain modified hexagonal boron nitride; S2: Take 2g of modified hexagonal boron nitride and add it to 50mL of N,N-dimethylacetamide. Sonicate for 1.5h to obtain a modified hexagonal boron nitride dispersion. Step 2: Preparation of the organic layer S1: Take 140g of polyetheramine, pass carbon dioxide through it, and react for 12h under the conditions of 8MPa pressure, 180℃ temperature and 200rpm rotation speed. After cooling and removing impurities, dry under vacuum at 75℃ for 24h to obtain polyurea oligomer. S2: Under a nitrogen atmosphere, 20g of polyurea oligomer was added to 150mL of N,N-dimethylacetamide. The mixture was stirred until completely dissolved at 70℃. 29.42g of 4,4'-biphenyl dianhydride was added, and the reaction was allowed to proceed for 0.5h. Then, 21.68g of 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and 100mL of N,N-dimethylacetamide were added, and the mixture was stirred until completely dissolved. The reaction was allowed to proceed for 22h at 70℃. After cooling, a polyimide solution was obtained. The modified hexagonal boron nitride dispersion and the polyimide solution were mixed thoroughly to obtain an organic solution. S3: Take copper foil with a thickness of 10µm, clean it, blow it dry, and thin the middle area on both sides of the copper foil to obtain an H-shaped copper foil; take an organic solution, coat it evenly on the thinned middle area of ​​the H-shaped copper foil, dry it, cure it, and cool it to obtain an organic layer with a thickness of 2µm. Step 2: Preparation of current collectors with high structural stability First, copper is deposited on the organic layer by magnetron sputtering, and then electrodeposition is performed on its surface. The anode sample is 1 cm². 2 For copper sheets, add 50g of copper sulfate pentahydrate to 800mL of deionized water and stir until completely dissolved. Add 55mL of concentrated sulfuric acid, 0.08g of sodium chloride, 0.45g of polyethylene glycol, 0.5g of dodecyltrimethylammonium bromide, 0.15g of benzotriazole, and 0.1g of 2-aminobenzothiazole. Mix well and bring the volume to 1L. Let stand, filter, and obtain the electrodeposition solution. At a current density of 2.5A / cm², [the solution is prepared]. 2 At a deposition temperature of 25°C, deposition was carried out for 15 seconds, followed by vacuum drying to obtain a metal layer with a thickness of 1µm.

[0026] Comparative Example 3: No polyurea oligomers were added; all other aspects are the same as in Example 2. Step 1: Preparation of modified hexagonal boron nitride dispersion S1: Take 3g of hexagonal boron nitride and add it to 60mL of 2mol / L sodium hydroxide aqueous solution. Add 210g of grinding balls and ball mill at 250rpm for 24h. Wash, vacuum dry, add to 150mL of anhydrous toluene, sonicate for 1.5h, add 4.5g of 3-glycidyl etheroxypropyltrimethoxysilane, purge with nitrogen, react at 83℃ for 24h, wash, vacuum dry, add to 90mL of N,N-dimethylformamide, add 2.5g of p-aminobenzoic acid and 2mL of triethylamine, purge with nitrogen, react at 95℃ for 12h, wash, vacuum dry to obtain modified hexagonal boron nitride; S2: Take modified hexagonal boron nitride, sieve it to obtain modified hexagonal boron nitride A and modified hexagonal boron nitride B. The particle size of modified hexagonal boron nitride A is 50-100nm and the particle size of modified hexagonal boron nitride B is 200-400nm. Take modified hexagonal boron nitride A and modified hexagonal boron nitride B at a mass ratio of 1:1, mix them evenly to obtain a modified hexagonal boron nitride mixture; take 2g of the modified hexagonal boron nitride mixture and add it to 50mL of N,N-dimethylacetamide, sonicate for 1.5h to obtain a modified hexagonal boron nitride dispersion; Step 2: Preparation of the organic layer S1: Under a nitrogen atmosphere, 150 mL of N,N-dimethylacetamide was taken and stirred until completely dissolved at 70 °C. 29.42 g of 4,4'-biphenyl dianhydride was added, and the reaction was carried out for 0.5 h. Then, 21.68 g of 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and 100 mL of N,N-dimethylacetamide were added, and the mixture was stirred until completely dissolved. The reaction was carried out at 70 °C for 22 h. After cooling, a polyimide solution was obtained. The modified hexagonal boron nitride dispersion and the polyimide solution were mixed evenly to obtain an organic solution. S2: Take a copper foil with a thickness of 10µm, clean it, dry it, and thin the middle area on both sides of the copper foil to obtain an H-shaped copper foil; take an organic solution, coat it evenly on the thinned middle area of ​​the H-shaped copper foil, dry it, cure it, and cool it to obtain an organic layer with a thickness of 2µm. Step 2: Preparation of current collectors with high structural stability First, copper is deposited on the organic layer by magnetron sputtering, and then electrodeposition is performed on its surface. The anode sample is 1 cm². 2 For copper sheets, add 50g of copper sulfate pentahydrate to 800mL of deionized water and stir until completely dissolved. Add 55mL of concentrated sulfuric acid, 0.08g of sodium chloride, 0.45g of polyethylene glycol, 0.5g of dodecyltrimethylammonium bromide, 0.15g of benzotriazole, and 0.1g of 2-aminobenzothiazole. Mix well and bring the volume to 1L. Let stand, filter, and obtain the electrodeposition solution. At a current density of 2.5A / cm², [the solution is prepared]. 2 At a deposition temperature of 25°C, deposition was carried out for 15 seconds, followed by vacuum drying to obtain a metal layer with a thickness of 1µm.

[0027] Comparative Example 4: 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was replaced with 4,4'-diaminodiphenyl ether, and the rest were the same as in Example 2; Step 1: Preparation of modified hexagonal boron nitride dispersion S1: Take 3g of hexagonal boron nitride and add it to 60mL of 2mol / L sodium hydroxide aqueous solution. Add 210g of grinding balls and ball mill at 250rpm for 24h. Wash, vacuum dry, add to 150mL of anhydrous toluene, sonicate for 1.5h, add 4.5g of 3-glycidyl etheroxypropyltrimethoxysilane, purge with nitrogen, react at 83℃ for 24h, wash, vacuum dry, add to 90mL of N,N-dimethylformamide, add 2.5g of p-aminobenzoic acid and 2mL of triethylamine, purge with nitrogen, react at 95℃ for 12h, wash, vacuum dry to obtain modified hexagonal boron nitride; S2: Take modified hexagonal boron nitride, sieve it to obtain modified hexagonal boron nitride A and modified hexagonal boron nitride B. The particle size of modified hexagonal boron nitride A is 50-100nm and the particle size of modified hexagonal boron nitride B is 200-400nm. Take modified hexagonal boron nitride A and modified hexagonal boron nitride B at a mass ratio of 1:1, mix them evenly to obtain a modified hexagonal boron nitride mixture; take 2g of the modified hexagonal boron nitride mixture and add it to 50mL of N,N-dimethylacetamide, sonicate for 1.5h to obtain a modified hexagonal boron nitride dispersion; Step 2: Preparation of the organic layer S1: Take 140g of polyetheramine, pass carbon dioxide through it, and react for 12h under the conditions of 8MPa pressure, 180℃ temperature and 200rpm rotation speed. After cooling and removing impurities, dry under vacuum at 75℃ for 24h to obtain polyurea oligomer. S2: Under a nitrogen atmosphere, 20g of polyurea oligomer was added to 150mL of N,N-dimethylacetamide. The mixture was stirred until completely dissolved at 70℃. 29.42g of 4,4'-biphenyl ether dianhydride was added, and the reaction was carried out for 0.5h. Then, 21.68g of 4,4'-diaminodiphenyl ether and 100mL of N,N-dimethylacetamide were added, and the mixture was stirred until completely dissolved. The reaction was carried out at 70℃ for 22h. After cooling, a polyimide solution was obtained. The modified hexagonal boron nitride dispersion and the polyimide solution were mixed evenly to obtain an organic solution. S3: Take copper foil with a thickness of 10µm, clean it, blow it dry, and thin the middle area on both sides of the copper foil to obtain an H-shaped copper foil; take an organic solution, coat it evenly on the thinned middle area of ​​the H-shaped copper foil, dry it, cure it, and cool it to obtain an organic layer with a thickness of 2µm. Step 2: Preparation of current collectors with high structural stability First, copper is deposited on the organic layer by magnetron sputtering, and then electrodeposition is performed on its surface. The anode sample is 1 cm². 2 For copper sheets, add 50g of copper sulfate pentahydrate to 800mL of deionized water and stir until completely dissolved. Add 55mL of concentrated sulfuric acid, 0.08g of sodium chloride, 0.45g of polyethylene glycol, 0.5g of dodecyltrimethylammonium bromide, 0.15g of benzotriazole, and 0.1g of 2-aminobenzothiazole. Mix well and bring the volume to 1L. Let stand, filter, and obtain the electrodeposition solution. At a current density of 2.5A / cm², [the solution is prepared]. 2 At a deposition temperature of 25°C, deposition was carried out for 15 seconds, followed by vacuum drying to obtain a metal layer with a thickness of 1µm.

[0028] Comparative Example 5: No electrodeposition was performed; all other aspects are the same as in Example 2. Step 1: Preparation of modified hexagonal boron nitride dispersion S1: Take 3g of hexagonal boron nitride and add it to 60mL of 2mol / L sodium hydroxide aqueous solution. Add 210g of grinding balls and ball mill at 250rpm for 24h. Wash, vacuum dry, add to 150mL of anhydrous toluene, sonicate for 1.5h, add 4.5g of 3-glycidyl etheroxypropyltrimethoxysilane, purge with nitrogen, react at 83℃ for 24h, wash, vacuum dry, add to 90mL of N,N-dimethylformamide, add 2.5g of p-aminobenzoic acid and 2mL of triethylamine, purge with nitrogen, react at 95℃ for 12h, wash, vacuum dry to obtain modified hexagonal boron nitride; S2: Take modified hexagonal boron nitride, sieve it to obtain modified hexagonal boron nitride A and modified hexagonal boron nitride B. The particle size of modified hexagonal boron nitride A is 50-100nm and the particle size of modified hexagonal boron nitride B is 200-400nm. Take modified hexagonal boron nitride A and modified hexagonal boron nitride B at a mass ratio of 1:1, mix them evenly to obtain a modified hexagonal boron nitride mixture; take 2g of the modified hexagonal boron nitride mixture and add it to 50mL of N,N-dimethylacetamide, sonicate for 1.5h to obtain a modified hexagonal boron nitride dispersion; Step 2: Preparation of the organic layer S1: Take 140g of polyetheramine, pass carbon dioxide through it, and react for 12h under the conditions of 8MPa pressure, 180℃ temperature and 200rpm rotation speed. After cooling and removing impurities, dry under vacuum at 75℃ for 24h to obtain polyurea oligomer. S2: Under a nitrogen atmosphere, 20g of polyurea oligomer was added to 150mL of N,N-dimethylacetamide. The mixture was stirred until completely dissolved at 70℃. 29.42g of 4,4'-biphenyl dianhydride was added, and the reaction was allowed to proceed for 0.5h. Then, 21.68g of 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and 100mL of N,N-dimethylacetamide were added, and the mixture was stirred until completely dissolved. The reaction was allowed to proceed for 22h at 70℃. After cooling, a polyimide solution was obtained. The modified hexagonal boron nitride dispersion and the polyimide solution were mixed thoroughly to obtain an organic solution. S3: Take copper foil with a thickness of 10µm, clean it, blow it dry, and thin the middle area on both sides of the copper foil to obtain an H-shaped copper foil; take an organic solution, coat it evenly on the thinned middle area of ​​the H-shaped copper foil, dry it, cure it, and cool it to obtain an organic layer with a thickness of 2µm. Step 2: Preparation of current collectors with high structural stability Copper was deposited on the organic layer by magnetron sputtering and then vacuum dried to obtain a metal layer with a thickness of 1µm.

[0029] Comparative Example 6: Benzotriazole was not added; all other aspects are the same as in Example 2. Step 1: Preparation of modified hexagonal boron nitride dispersion S1: Take 3g of hexagonal boron nitride and add it to 60mL of 2mol / L sodium hydroxide aqueous solution. Add 210g of grinding balls and ball mill at 250rpm for 24h. Wash, vacuum dry, add to 150mL of anhydrous toluene, sonicate for 1.5h, add 4.5g of 3-glycidyl etheroxypropyltrimethoxysilane, purge with nitrogen, react at 83℃ for 24h, wash, vacuum dry, add to 90mL of N,N-dimethylformamide, add 2.5g of p-aminobenzoic acid and 2mL of triethylamine, purge with nitrogen, react at 95℃ for 12h, wash, vacuum dry to obtain modified hexagonal boron nitride; S2: Take modified hexagonal boron nitride, sieve it to obtain modified hexagonal boron nitride A and modified hexagonal boron nitride B. The particle size of modified hexagonal boron nitride A is 50-100nm and the particle size of modified hexagonal boron nitride B is 200-400nm. Take modified hexagonal boron nitride A and modified hexagonal boron nitride B at a mass ratio of 1:1, mix them evenly to obtain a modified hexagonal boron nitride mixture; take 2g of the modified hexagonal boron nitride mixture and add it to 50mL of N,N-dimethylacetamide, sonicate for 1.5h to obtain a modified hexagonal boron nitride dispersion; Step 2: Preparation of the organic layer S1: Take 140g of polyetheramine, pass carbon dioxide through it, and react for 12h under the conditions of 8MPa pressure, 180℃ temperature and 200rpm rotation speed. After cooling and removing impurities, dry under vacuum at 75℃ for 24h to obtain polyurea oligomer. S2: Under a nitrogen atmosphere, 20g of polyurea oligomer was added to 150mL of N,N-dimethylacetamide. The mixture was stirred until completely dissolved at 70℃. 29.42g of 4,4'-biphenyl dianhydride was added, and the reaction was allowed to proceed for 0.5h. Then, 21.68g of 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and 100mL of N,N-dimethylacetamide were added, and the mixture was stirred until completely dissolved. The reaction was allowed to proceed for 22h at 70℃. After cooling, a polyimide solution was obtained. The modified hexagonal boron nitride dispersion and the polyimide solution were mixed thoroughly to obtain an organic solution. S3: Take copper foil with a thickness of 10µm, clean it, blow it dry, and thin the middle area on both sides of the copper foil to obtain an H-shaped copper foil; take an organic solution, coat it evenly on the thinned middle area of ​​the H-shaped copper foil, dry it, cure it, and cool it to obtain an organic layer with a thickness of 2µm. Step 2: Preparation of current collectors with high structural stability First, copper is deposited on the organic layer by magnetron sputtering, and then electrodeposition is performed on its surface. The anode sample is 1 cm². 2For copper sheets, add 50g of copper sulfate pentahydrate to 800mL of deionized water and stir until completely dissolved. Add 55mL of concentrated sulfuric acid, 0.08g of sodium chloride, 0.45g of polyethylene glycol, 0.5g of dodecyltrimethylammonium bromide, and 0.1g of 2-aminobenzothiazole. Mix well and bring the volume to 1L. Let stand, filter, and obtain the electrodeposition solution. At a current density of 2.5A / cm², [the solution is prepared]. 2 At a deposition temperature of 25°C, deposition was carried out for 15 seconds, followed by vacuum drying to obtain a metal layer with a thickness of 1µm.

[0030] Comparative Example 7: No thinning treatment was performed; all other aspects are the same as in Example 2. Step 1: Preparation of modified hexagonal boron nitride dispersion S1: Take 3g of hexagonal boron nitride and add it to 60mL of 2mol / L sodium hydroxide aqueous solution. Add 210g of grinding balls and ball mill at 250rpm for 24h. Wash, vacuum dry, add to 150mL of anhydrous toluene, sonicate for 1.5h, add 4.5g of 3-glycidyl etheroxypropyltrimethoxysilane, purge with nitrogen, react at 83℃ for 24h, wash, vacuum dry, add to 90mL of N,N-dimethylformamide, add 2.5g of p-aminobenzoic acid and 2mL of triethylamine, purge with nitrogen, react at 95℃ for 12h, wash, vacuum dry to obtain modified hexagonal boron nitride; S2: Take modified hexagonal boron nitride, sieve it to obtain modified hexagonal boron nitride A and modified hexagonal boron nitride B. The particle size of modified hexagonal boron nitride A is 50-100nm and the particle size of modified hexagonal boron nitride B is 200-400nm. Take modified hexagonal boron nitride A and modified hexagonal boron nitride B at a mass ratio of 1:1, mix them evenly to obtain a modified hexagonal boron nitride mixture; take 2g of the modified hexagonal boron nitride mixture and add it to 50mL of N,N-dimethylacetamide, sonicate for 1.5h to obtain a modified hexagonal boron nitride dispersion; Step 2: Preparation of the organic layer S1: Take 140g of polyetheramine, pass carbon dioxide through it, and react for 12h under the conditions of 8MPa pressure, 180℃ temperature and 200rpm rotation speed. After cooling and removing impurities, dry under vacuum at 75℃ for 24h to obtain polyurea oligomer. S2: Under a nitrogen atmosphere, 20g of polyurea oligomer was added to 150mL of N,N-dimethylacetamide. The mixture was stirred until completely dissolved at 70℃. 29.42g of 4,4'-biphenyl dianhydride was added, and the reaction was allowed to proceed for 0.5h. Then, 21.68g of 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and 100mL of N,N-dimethylacetamide were added, and the mixture was stirred until completely dissolved. The reaction was allowed to proceed for 22h at 70℃. After cooling, a polyimide solution was obtained. The modified hexagonal boron nitride dispersion and the polyimide solution were mixed thoroughly to obtain an organic solution. S3: Take a copper foil with a thickness of 10µm, clean it, blow it dry, take an organic solution, coat it evenly on the copper foil, dry it, cure it, cool it to obtain an organic layer with a thickness of 2µm; Step 2: Preparation of current collectors with high structural stability First, copper is deposited on the organic layer by magnetron sputtering, and then electrodeposition is performed on its surface. The anode sample is 1 cm². 2 For copper sheets, add 50g of copper sulfate pentahydrate to 800mL of deionized water and stir until completely dissolved. Add 55mL of concentrated sulfuric acid, 0.08g of sodium chloride, 0.45g of polyethylene glycol, 0.5g of dodecyltrimethylammonium bromide, 0.15g of benzotriazole, and 0.1g of 2-aminobenzothiazole. Mix well and bring the volume to 1L. Let stand, filter, and obtain the electrodeposition solution. At a current density of 2.5A / cm², [the solution is prepared]. 2 At a deposition temperature of 25°C, deposition was carried out for 15 seconds, followed by vacuum drying to obtain a metal layer with a thickness of 1µm.

[0031] experiment: The high structural stability current collectors prepared in Examples 1-3 and Comparative Examples 1-7 were tested. (1) Electrochemical performance measurement A positive electrode slurry was prepared using 96% lithium iron phosphate, 2.5% polyvinylidene fluoride, 1.1% carbon nanotubes, and 0.4% carbon black. A negative electrode slurry was then prepared using 66.2% graphite, 28.4% hard carbon, 2.1% styrene-butadiene rubber, 1.8% carbon black, and 1.5% sodium carboxymethyl cellulose. Aluminum foil and the high-structural-stability current collectors prepared in Examples 1-3 and Comparative Examples 1-7 were uniformly coated onto the positive and negative electrode slurries, respectively. The coatings were then dried, rolled, cut, and dried again to obtain the electrode sheets. The cells are stacked, assembled, and baked. Ethyl carbonate and diethyl carbonate are mixed evenly at a volume ratio of 1:1. 1 mol / L lithium hexafluorophosphate is added to obtain a mixed solution as a liquid electrolyte. The solution is injected and packaged to obtain a 20Ah soft-pack stacked battery. The 20Ah soft-pack stacked battery is activated at 0.2C for two cycles. Under the conditions of temperature 25℃ and charge / discharge voltage 2.5-4.2V, a 1C constant current charge / discharge cycle test is performed. The discharge specific capacity before and after 500 cycles is recorded, and the capacity retention rate is calculated. (2) Corrosion resistance test Select a current collector with high structural stability with a size of 14mm×14mm, immerse it completely in a 3.5mol / L sodium chloride aqueous solution, and observe the shedding of the surface metal layer. Once metal fragments are shed, record the time immediately. The data obtained from the above experiment are shown in Table 1 below: Table 1

[0032] Conclusion: Based on the analysis of the above experimental data, the current collectors with high structural stability prepared in Examples 1-3 of this invention have high capacity retention and corrosion time, excellent structural stability, and superior performance; while the current collectors with high structural stability prepared in Comparative Examples 1-7 have low capacity retention and corrosion time, poor structural stability, and poor performance.

[0033] Comparative analysis of Comparative Example 1 (without 3-glycidoxypropyltrimethoxysilane) and Example 2 shows that, through the shear force generated by the friction between the grinding balls and hexagonal boron nitride during ball milling, the interlayer of hexagonal boron nitride is peeled off and exposed to sodium hydroxide solution, resulting in edge hydroxylation, the introduction of hydroxyl groups, and the reaction with silanols formed by the hydrolysis of trimethoxysilane of 3-glycidoxypropyltrimethoxysilane, introducing epoxy groups. Under the catalysis of triethylamine, a ring-opening reaction occurs with the amino group of p-aminobenzoic acid, introducing carboxyl groups, thus obtaining modified hexagonal boron nitride, which improves the dispersibility of hexagonal boron nitride in the organic layer and the interfacial bonding strength of the polyimide matrix.

[0034] Comparative analysis of Comparative Example 2 (without sieving) and Example 2 shows that sieving yields modified hexagonal boron nitride A and modified hexagonal boron nitride B. The particle size of modified hexagonal boron nitride A is 50-100 nm, and the particle size of modified hexagonal boron nitride B is 200-400 nm. On the one hand, the combination of smaller and larger particle sizes of modified hexagonal boron nitride constructs a multi-sized rough surface, which improves the interfacial bonding strength between the organic layer and the metal foil, and between the metal layers, through mechanical interlocking. On the other hand, by dispersing in the organic layer, it suppresses the generation of microcracks and improves structural stability.

[0035] Comparative analysis of Comparative Example 3 (without polyurea oligomers) and Example 2 shows that under high temperature and high pressure conditions, the amino groups of polyetheramine react with carbon dioxide to form urea bonds, resulting in polyurea oligomers. The long-chain polyether structure of polyetheramine improves the flexibility of the organic layer, buffers the volume expansion and contraction of the active material during charging and discharging, and improves structural stability.

[0036] Comparative Example 4, in which 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was replaced with 4,4'-diaminodiphenyl ether, was compared with Example 2. It was found that adding 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane for chain extension to form a polyimide solution, introducing hydroxyl and hexafluoropropane groups, improved the interfacial bonding strength between the polyimide and the metal foil and metal layer, and enhanced the structural stability.

[0037] Comparative analysis of Comparative Example 5 (without electrodeposition) and Example 2 shows that polyethylene glycol is used as a leveling agent, dodecyltrimethylammonium bromide as a grain refiner and surfactant, and benzotriazole and 2-aminobenzothiazole as corrosion inhibitors. Electrodeposition of three-dimensional micro / nano porous copper on a copper layer has several advantages. First, the three-dimensional micro / nano porous structure has numerous pores and a large internal space, which buffers the volume expansion stress during battery charging and discharging, improving structural stability. Second, it reduces current density, suppresses lithium dendrite formation, and improves structural stability, safety, and battery performance.

[0038] Comparative analysis of Comparative Example 6 (without benzotriazole) and Example 2 shows that benzotriazole and 2-aminobenzothiazole act as corrosion inhibitors, improving the corrosion resistance of the current collector and thus improving battery performance.

[0039] Comparative analysis of Comparative Example 7 (without thinning treatment) and Example 2 shows that thinning the middle layer on both sides of the copper foil to obtain an H-shaped copper foil, and constructing an organic layer and a metal layer on the H-shaped copper foil, on the one hand, increases the contact area between the organic layer and the metal foil and metal layer, and improves the interfacial bonding strength and structural stability through the mechanical interlocking effect; on the other hand, it reduces the thickness of the current collector, increases the energy density of the battery, and improves the battery performance.

[0040] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A current collector with high structural stability, characterized in that: The current collector includes a metal foil, an organic layer, and a metal layer. The metal foil is an H-shaped copper foil prepared by thinning the middle area on both sides of a copper foil. An organic layer and a metal layer are sequentially placed on the metal foil. The thickness of the copper foil is 6-12µm, the thickness of the organic layer is 1-3µm, and the thickness of the metal layer is 0.5-2µm.

2. A method for preparing a current collector with high structural stability, characterized in that: Includes the following steps: Step 1: Take copper foil, clean it, dry it, and thin the middle area on both sides of the copper foil to obtain an H-shaped copper foil, i.e., a metal foil. Step 2: Take an organic solution and apply it evenly to the thinned area in the middle of the H-shaped copper foil. Dry, cure, and cool to obtain an organic layer. Step 3: First, deposit copper on the organic layer by magnetron sputtering, then add electrodeposition solution for electrodeposition, and vacuum dry to obtain the metal layer; The organic solution is prepared by taking modified hexagonal boron nitride dispersion and polyimide solution, mixing them evenly to obtain the organic solution.

3. The method for preparing a high structural stability current collector according to claim 2, characterized in that: The preparation method of the modified hexagonal boron nitride dispersion is as follows: take modified hexagonal boron nitride, sieve it to obtain modified hexagonal boron nitride A and modified hexagonal boron nitride B, take modified hexagonal boron nitride A and modified hexagonal boron nitride B, mix them evenly to obtain a modified hexagonal boron nitride mixture; add the modified hexagonal boron nitride mixture to N,N-dimethylacetamide, sonicate for 1-2 hours to obtain the modified hexagonal boron nitride dispersion.

4. The method for preparing a high structural stability current collector according to claim 2, characterized in that: The polyimide solution is prepared as follows: Under a nitrogen atmosphere, polyurea oligomer is added to N,N-dimethylacetamide and stirred until completely dissolved at 70-80°C. Then, 4,4'-biphenyl dianhydride is added and reacted for 0.5-1.5 h. Next, 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and N,N-dimethylacetamide are added and stirred until completely dissolved. The mixture is then reacted at 70-80°C for 22-26 h and cooled to obtain the polyimide solution.

5. The method for preparing a high structural stability current collector according to claim 3, characterized in that: The modified hexagonal boron nitride A has a particle size of 50-100 nm, the modified hexagonal boron nitride B has a particle size of 200-400 nm, and the mass ratio of modified hexagonal boron nitride A to modified hexagonal boron nitride B is (0.8-1.2):(0.8-1.2).

6. The method for preparing a high structural stability current collector according to claim 3, characterized in that: The modified hexagonal boron nitride is prepared as follows: Hexagonal boron nitride is added to an aqueous sodium hydroxide solution, grinding balls are added, and the mixture is ball-milled for 22-26 hours at a speed of 200-300 rpm. After washing and vacuum drying, the mixture is added to anhydrous toluene and sonicated for 1-2 hours. Then, 3-glycidyl etheroxypropyltrimethoxysilane is added, nitrogen gas is introduced, and the mixture is reacted for 22-26 hours at a temperature of 80-85℃. After washing and vacuum drying, the mixture is added to N,N-dimethylformamide, p-aminobenzoic acid and triethylamine are added, nitrogen gas is introduced, and the mixture is reacted for 10-14 hours at a temperature of 90-100℃. After washing and vacuum drying, the modified hexagonal boron nitride is obtained.

7. The method for preparing a high structural stability current collector according to claim 4, characterized in that: The preparation method of the polyurea oligomer is as follows: take polyetheramine, introduce carbon dioxide, react for 10-14 hours under the conditions of pressure 6-10 MPa, temperature 150-200℃ and rotation speed 200-300 rpm, cool, remove impurities, and vacuum dry for 22-26 hours under the conditions of temperature 70-80℃ to obtain polyurea oligomer.

8. The method for preparing a high structural stability current collector according to claim 2, characterized in that: The electrodeposition solution uses deionized water as a solvent and includes the following components, listed in terms of concentration: 40-60 g / L copper sulfate pentahydrate, 80-120 g / L concentrated sulfuric acid, 50-100 mg / L sodium chloride, 0.4-0.5 g / L polyethylene glycol, 0.4-0.6 g / L dodecyltrimethylammonium bromide, 0.1-0.2 g / L benzotriazole, and 0.05-0.2 g / L 2-aminobenzothiazole.

9. The method for preparing a high structural stability current collector according to claim 2, characterized in that: The electrodeposition solution is prepared as follows: copper sulfate pentahydrate is added to deionized water and stirred until completely dissolved. Concentrated sulfuric acid, sodium chloride, polyethylene glycol, dodecyltrimethylammonium bromide, benzotriazole, and 2-aminobenzothiazole are added, mixed evenly, brought to a final volume, allowed to stand, and filtered to obtain the electrodeposition solution.

Images