High-adhesion nano-coated copper current collector and method of making same

Abstract

The application relates to the technical field of copper current collectors, and particularly discloses a high-adhesion nano-coated copper current collector and a preparation method thereof. The conductive agent, the binder, the cross-linking agent and the anchoring agent are mixed and then coated on the copper current collector, the method is simple, the manufacturing cost is low, the peeling performance of the negative electrode material and the current collector is remarkably improved, the prepared high-adhesion nano-coated copper current collector has high water resistance, peeling strength, conductivity and safety, after rolling, the peeling strength of the high-adhesion nano-coated copper current collector is further enhanced, and the further processing of the electrode material is facilitated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of copper current collector, in particular to a high-adhesion nano-coated copper current collector and a preparation method thereof. BACKGROUND

[0002] Lithium ion batteries have gradually begun to be applied in the fields of consumer electronics, electric vehicles, etc., and the market has also put forward higher requirements for the energy density, cycle life, use safety, etc. of lithium ion batteries. The current collector is an important component of a lithium ion battery, which plays a role in collecting electrons, supporting active materials and stabilizing the structure of the battery. In the negative electrode system, the conductive primer technology of the current collector can effectively improve the rate performance of the battery, increase the adhesion between the electrode material and the current collector, and prolong the service life of the battery.

[0003] In the prior art, copper foil is usually used as the negative electrode current collector material of a lithium ion battery. For the negative electrode, the negative electrode material is mostly a water-based system, and the nano-coated copper current collector has good water and electrolyte resistance and strong adhesion during the preparation process. However, the commonly used nano-coating is a water-based adhesive, which can cause partial dissolution and slippage of the nano-coating during the coating of the negative electrode material, affecting the peeling performance of the negative electrode material and the current collector. On the other hand, the impact is further amplified during the rolling process after the coating of the negative electrode material, which further aggravates the slippage of the nano-coating. This is the reason why the peeling strength of the nano-coated copper current collector after rolling is lower than that before rolling in the prior art, thereby affecting the overall performance of the electrode. SUMMARY

[0004] The purpose of the present application is to provide a high-adhesion nano-coated copper current collector and a preparation method thereof. By increasing the water resistance of the nano-coating and improving the anti-slippage ability of the nano-coating, the penetration ability of water in the coating film is reduced, the adhesion between the nano-coating and the negative electrode material is improved, and the overall conductivity of the current collector is not affected, thereby solving the problem of the influence of the existing adhesive on the peeling strength between the negative electrode material and the current collector.

[0005] In order to solve the above technical problems, the present application provides the following technical solutions:

[0006] A high-adhesion nano-coated copper current collector, comprising a copper current collector and a nano-coating coated on the surface of the copper current collector, wherein the amount of each component in the nano-coating is as follows: 6-22 parts of a conductive agent, 0.05-4 parts of an anchoring agent, 0.5-1.5 parts of a modified polyacrylic acid adhesive, and 0.01-0.1 parts of a crosslinking agent.

[0007] As a limitation of the present application, the conductive agent comprises a conductive agent A and a conductive agent B, the conductive agent A is at least one of conductive carbon black and carbon nanotubes, the conductive agent B is at least one of conductive graphite and graphene, the particle size of the conductive agent B is 1-2 μm, and the mass ratio of the conductive agent A to the conductive agent B is (5-10):1.

[0008] As a limitation of the present application, the cross-linking agent is at least one of isocyanate, aziridine type curing agent and epoxy type curing cross-linking agent; the anchoring agent is at least one of alumina ceramic particles and boehmite.

[0009] A preparation method of a high-adhesion nano-coated copper current collector, the preparation method being:

[0010] The conductive agent A, the conductive agent B, the anchoring agent, the modified polyacrylic acid binder and deionized water are mixed, the cross-linking agent is added, and stirring is uniformly performed to obtain a nano-coating slurry, the nano-coating slurry is coated on a copper current collector to obtain a high-adhesion nano-coated copper current collector.

[0011] As a limitation of the present application, the modified polyacrylic acid binder has the following specific preparation steps:

[0012] Sodium hydroxide and deionized water are mixed and stirred uniformly to obtain a sodium hydroxide solution, acrylic acid is mixed with the sodium hydroxide solution at 0-10 DEG C to obtain a sodium acrylate solution, acrylamide is added to the sodium acrylate solution and stirred uniformly to obtain a sodium acrylate-acrylamide mixed solution, methyl alkenyl polyoxyethylene ether and deionized water are mixed and stirred uniformly until completely dissolved, the sodium acrylate-acrylamide mixed solution, acrylonitrile and ammonium persulfate are added under nitrogen protection, and reaction is carried out at 65-75 DEG C and 250-350 rpm for 8-10 h, after the reaction is completed, the temperature is lowered, freeze-drying is performed, anhydrous ethanol is used for washing, and suction filtration is performed to obtain the modified polyacrylic acid binder.

[0013] As a limitation of the present application, the copper current collector is a cuprous bromide surface modified copper current collector, and the preparation method is:

[0014] The copper current collector is washed with ethanol and deionized water to remove dust and impurities on the surface, and is dried at room temperature to obtain a pretreated copper current collector, copper sulfate pentahydrate and deionized water are mixed and stirred uniformly, dodecyltrimethylammonium bromide is added, and ultrasonic dispersion is performed to form a mixed solution, the pretreated copper current collector is placed in the mixed solution, and is immersed at room temperature for 5-20 min, after the immersion is completed, the copper current collector is taken out, washed with deionized water, and dried to obtain a cuprous bromide surface modified copper current collector.

[0015] As a limitation of the present application, the copper current collector is a cuprous iodide surface modified copper current collector, and the preparation method is:

[0016] The copper current collector is washed with ethanol and deionized water to remove dust and impurities on the surface, and dried at room temperature to obtain a pretreated copper current collector; copper sulfate pentahydrate and deionized water are mixed and stirred uniformly, 1-butyl-3-methyl imidazole iodide is added and ultrasonically dispersed to form a mixed solution; the pretreated copper current collector is placed in the mixed solution and immersed at room temperature for 5-20 min; after the immersion is completed, the copper current collector is taken out, washed with deionized water and dried to obtain a cuprous iodide surface modified current collector.

[0017] As a limitation of the application, the modified polyacrylic acid binder is a polydopamine-modified polyacrylic acid binder, and the preparation method is as follows:

[0018] Dopamine is mixed with a tris-hydroxymethyl aminomethane hydrochloride buffer solution, stirred at room temperature for 6-10 h to obtain a polydopamine solution; the polydopamine solution and the modified polyacrylic acid binder are mixed uniformly to obtain a polydopamine-modified polyacrylic acid binder.

[0019] Application of a high-adhesion nano-coated current collector in a negative material of a lithium ion battery.

[0020] Compared with the prior art, the application has the following beneficial effects:

[0021] By depositing a layer of cuprous halide film on the surface of the copper current collector, the roughness of the surface of the copper current collector is increased, and the adhesion between the binder and the copper current collector is enhanced.

[0022] By modifying the acrylic acid binder, the modified binder has active groups such as carboxyl and amide groups or has an o-benzoquinone structure and an amine group, which can improve the dispersibility and adhesion of the binder. In addition, the cyano and amide groups can promote the conduction of ions or electrons, thereby improving the rate performance of the battery, and the polyoxyethylene ether chain segment can provide elasticity and ionic conductivity to the binder, thereby preventing the active material from falling off during deformation.

[0023] By cross-linking and adding an anchoring agent, the water resistance and compaction resistance of the traditional nano-coated copper current collector are improved, the nano-coated copper current collector has high water resistance, peel strength, high conductivity and safety, and has low manufacturing cost and simple method. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the application will be described below in a clear and complete manner. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0025] Conductive carbon black (50 nm), conductive graphite (2 pm) were supplied by Sigma-Aldrich (Shanghai), copper current collector (6 pm) was supplied by Far East Copper Foil, methallyl polyoxyethylene ether (molecular weight 2400), aziridine crosslinking agent (Sac100, 1.08 kg / L) were supplied by Jinjile Chemical, polyacrylic acid (molecular weight 2000), tris-hydroxymethyl aminomethane hydrochloride buffer (pH = 8) were supplied by Shanghai Yinn Chemical.

[0026] Example 1: A method for preparing a high-adhesion nano-coated copper current collector, specifically:

[0027] Mix 10 kg of conductive carbon black, 1 kg of conductive graphite, 1 kg of aluminum oxide, 40 kg of 25 wt% modified polyacrylic acid binder, and 168 kg of deionized water, add 0.1 kg of aziridine crosslinking agent, stir uniformly to obtain a nano-coating slurry, coat the obtained nano-coating slurry on a 6 pm copper current collector, the coating thickness is 1 pm, thus obtaining a high-adhesion nano-coated copper current collector.

[0028] The preparation method of the modified acrylic acid binder is:

[0029] Mix 8.5 kg of sodium hydroxide and 42.5 kg of deionized water, stir uniformly to obtain a sodium hydroxide solution, mix 15 kg of acrylic acid with the sodium hydroxide solution at 5°C to obtain a sodium acrylate solution, add 4 kg of acrylamide to the sodium acrylate solution, stir uniformly to obtain a sodium acrylate-acrylamide mixed solution, mix 0.75 kg of methallyl polyoxyethylene ether and 20 kg of deionized water, stir uniformly to completely dissolve, under nitrogen protection, add the sodium acrylate-acrylamide mixed solution, 6 kg of acrylonitrile, and 1.25 kg of ammonium persulfate, react at 70°C and 300 rpm for 9 h, after the reaction is completed, cool down, freeze-dry, wash with anhydrous ethanol, and suction-filter to obtain a modified acrylic acid binder, dissolve in 75 kg of deionized water to obtain a 25 wt% modified acrylic acid binder.

[0030] Example 2: A method for preparing a high-adhesion nano-coated copper current collector, specifically:

[0031] Mix 10 kg of conductive carbon black, 2 kg of conductive graphite, 1 kg of aluminum oxide, 40 kg of 25 wt% modified polyacrylic acid binder, and 168 kg of deionized water, add 0.1 kg of aziridine crosslinking agent, stir uniformly to obtain a nano-coating slurry, coat the obtained nano-coating slurry on a 6 pm copper current collector, the coating thickness is 1 pm, thus obtaining a high-adhesion nano-coated copper current collector.

[0032] The preparation method of the modified acrylic acid binder is:

[0033] Mix 8.5 kg of sodium hydroxide and 42.5 kg of deionized water to obtain a sodium hydroxide solution, mix 15 kg of acrylic acid with the sodium hydroxide solution at 5°C to obtain a sodium acrylate solution, add 4 kg of acrylamide to the sodium acrylate solution, and stir until uniform to obtain a sodium acrylate-acrylamide mixed solution, mix 0.75 kg of methallyl polyoxyethylene ether and 20 kg of deionized water, stir until uniform, and completely dissolve, under nitrogen protection, add the sodium acrylate-acrylamide mixed solution, 6 kg of acrylonitrile, and 1.25 kg of ammonium persulfate, and react at 70°C and 300 rpm for 9 h, after the reaction is completed, cool down, freeze-dry, wash with anhydrous ethanol, and suction-filter to obtain a modified acrylic acid binder, and dissolve in 75 kg of deionized water to obtain a 25 wt% modified acrylic acid binder.

[0034] Example 3: A method for preparing a high-adhesion nano-coated copper current collector, specifically comprising:

[0035] Mix 10 kg of conductive carbon black, 1 kg of conductive graphite, 1 kg of aluminum oxide, 40 kg of 25 wt% modified polyacrylic acid binder, and 168 kg of deionized water, add 1 kg of aziridine crosslinking agent, and stir until uniform to obtain a nano-coating slurry, coat the obtained nano-coating slurry onto a 6 μm copper current collector to a thickness of 1 μm to obtain a high-adhesion nano-coated copper current collector.

[0036] The method for preparing the modified acrylic acid binder comprises:

[0037] Mix 8.5 kg of sodium hydroxide and 42.5 kg of deionized water to obtain a sodium hydroxide solution, mix 15 kg of acrylic acid with the sodium hydroxide solution at 5°C to obtain a sodium acrylate solution, add 4 kg of acrylamide to the sodium acrylate solution, and stir until uniform to obtain a sodium acrylate-acrylamide mixed solution, mix 0.75 kg of methallyl polyoxyethylene ether and 20 kg of deionized water, stir until uniform, and completely dissolve, under nitrogen protection, add the sodium acrylate-acrylamide mixed solution, 6 kg of acrylonitrile, and 1.25 kg of ammonium persulfate, and react at 70°C and 300 rpm for 9 h, after the reaction is completed, cool down, freeze-dry, wash with anhydrous ethanol, and suction-filter to obtain a modified acrylic acid binder, and dissolve in 75 kg of deionized water to obtain a 25 wt% modified acrylic acid binder.

[0038] Example 4: A method for preparing a high-adhesion nano-coated copper current collector, specifically comprising:

[0039] Mix 10 kg of conductive carbon black, 1 kg of conductive graphite, 1 kg of aluminum oxide, 40 kg of 25 wt% modified polyacrylic acid binder and 168 kg of deionized water, add 0.1 kg of aziridine type crosslinking agent, stir uniformly to obtain a nano coating slurry, coat the obtained nano coating slurry on the cuprous bromide surface modified copper current collector, and the coating thickness is 1 μm, thereby obtaining a high adhesion nano coating copper current collector.

[0040] The preparation method of the cuprous bromide surface modified copper current collector is:

[0041] The 6 μm copper current collector is washed with ethanol and deionized water to remove dust and impurities on the surface, and dried at room temperature to obtain a pretreated copper current collector.

[0042] Mix 15 kg of copper sulfate pentahydrate and 100 kg of deionized water, stir uniformly, add 0.46 kg of dodecyl trimethyl ammonium bromide, ultrasonic dispersion to form a mixed solution, put the pretreated copper current collector into the mixed solution, immerse at room temperature for 10 min, take out after the immersion is completed, wash with deionized water, dry to obtain a cuprous bromide surface modified copper current collector.

[0043] The preparation method of the modified acrylic acid binder is:

[0044] Mix 8.5 kg of sodium hydroxide and 42.5 kg of deionized water, stir uniformly to obtain a sodium hydroxide solution, mix 15 kg of acrylic acid with the sodium hydroxide solution at 5 ℃ to obtain a sodium acrylate solution, add 4 kg of acrylamide to the sodium acrylate solution, stir uniformly to obtain a sodium acrylate-acrylamide mixed solution, mix 0.75 kg of methyl allyl polyoxyethylene ether and 20 kg of deionized water, stir uniformly to completely dissolve, under nitrogen protection, add the sodium acrylate-acrylamide mixed solution, 6 kg of acrylonitrile, 1.25 kg of ammonium persulfate, react at 70 ℃ for 9 h under 300 rpm, cool down after the reaction is completed, freeze-dry, wash with anhydrous ethanol, and suction filter to obtain a modified acrylic acid binder, dissolve in 75 kg of deionized water to obtain a 25 wt% modified acrylic acid binder.

[0045] Example 5: A preparation method of a high adhesion nano coating copper current collector, specifically:

[0046] Mix 10 kg of conductive carbon black, 1 kg of conductive graphite, 1 kg of aluminum oxide, 40 kg of 25 wt% modified polyacrylic acid binder and 168 kg of deionized water, add 0.1 kg of aziridine type crosslinking agent, stir uniformly to obtain a nano coating slurry, coat the obtained nano coating slurry on the cuprous bromide surface modified copper current collector, and the coating thickness is 1 μm, thereby obtaining a high adhesion nano coating copper current collector.

[0047] The preparation method of the cuprous iodide surface modified copper current collector is as follows:

[0048] The 6-micron copper current collector was washed with ethanol and deionized water to remove dust and impurities on the surface, and dried at room temperature to obtain a pretreated copper current collector.

[0049] The 15 kg of copper sulfate pentahydrate and 100 kg of deionized water were mixed and stirred uniformly, 0.3 kg of 1-butyl-3-methyl-imidazole iodide was added and ultrasonically dispersed to form a mixed solution, the pretreated copper current collector was put into the mixed solution and immersed at room temperature for 10 min, then taken out, washed with deionized water and dried to obtain a cuprous iodide surface modified copper current collector.

[0050] The preparation method of the modified acrylic acid binder is as follows:

[0051] The 8.5 kg of sodium hydroxide and 42.5 kg of deionized water were mixed and stirred uniformly to obtain a sodium hydroxide solution, 15 kg of acrylic acid was mixed with the sodium hydroxide solution at 5℃ to obtain a sodium acrylate solution, 4 kg of acrylamide was added to the sodium acrylate solution and stirred uniformly to obtain a sodium acrylate-acrylamide mixed solution, 0.75 kg of methyl allyl polyoxyethylene ether and 20 kg of deionized water were mixed and stirred uniformly to completely dissolve, the sodium acrylate-acrylamide mixed solution, 6 kg of acrylonitrile and 1.25 kg of ammonium persulfate were added under nitrogen protection, and the reaction was carried out at 70℃ and 300 rpm for 9 h, then the reaction was cooled, freeze-dried, washed with anhydrous ethanol and suction filtered to obtain a modified acrylic acid binder, which was dissolved in 75 kg of deionized water to obtain a 25wt% modified acrylic acid binder.

[0052] Example 6: A preparation method of a high-adhesion nano-coated copper current collector, specifically as follows:

[0053] The 10 kg of conductive carbon black, 1 kg of conductive graphite, 1 kg of aluminum oxide, 40 kg of polydopamine-modified polyacrylic acid binder and 168 kg of deionized water were mixed, 0.1 kg of aziridine crosslinking agent was added and stirred uniformly to obtain a nano-coating slurry, the obtained nano-coating slurry was coated on the 6-micron copper current collector with a coating thickness of 1 micron to obtain a high-adhesion nano-coated copper current collector.

[0054] The preparation method of the cuprous bromide surface modified copper current collector is as follows:

[0055] The 6-micron copper current collector was washed with ethanol and deionized water to remove dust and impurities on the surface, and dried at room temperature to obtain a pretreated copper current collector.

[0056] Mixing 15 kg of copper sulfate pentahydrate and 100 kg of deionized water, stirring evenly, adding 0.46 kg of dodecyl trimethyl ammonium bromide, ultrasonic dispersion, forming a mixed solution, putting the pretreated copper current collector into the mixed solution, dipping at room temperature for 10 min, taking out after the dipping is completed, washing with deionized water, drying, and obtaining a cuprous iodide surface modified copper current collector.

[0057] The preparation method of the polydopamine-modified polyacrylic acid binder is:

[0058] Mixing 8.5 kg of sodium hydroxide and 42.5 kg of deionized water, stirring evenly, obtaining a sodium hydroxide solution, mixing 15 kg of acrylic acid with the sodium hydroxide solution at 5℃, obtaining a sodium acrylate solution, adding 4 kg of acrylamide to the sodium acrylate solution, stirring evenly, obtaining a sodium acrylate-acrylamide mixed solution, mixing 0.75 kg of methyl allyl polyoxyethylene ether and 20 kg of deionized water, stirring evenly, and making it completely dissolved, adding the sodium acrylate-acrylamide mixed solution, 6 kg of acrylonitrile, and 1.25 kg of ammonium persulfate under nitrogen protection, reacting at 70℃ for 9 h at 300 rpm, cooling after the reaction is completed, freeze-drying, washing with anhydrous ethanol, and suction filtering, obtaining a modified acrylic acid binder, dissolving in 75 kg of deionized water, and obtaining a 25 wt% modified acrylic acid binder.

[0059] Mixing 0.5 kg of dopamine with 9.5 kg of tris-hydroxymethyl aminomethane hydrochloride buffer, stirring at room temperature for 8 h, obtaining a polydopamine solution, mixing the polydopamine solution with 30 kg of 25 wt% modified acrylic acid binder, stirring evenly, and obtaining a polydopamine-modified polyacrylic acid binder.

[0060] Example 7: A preparation method of a high-adhesion nano-coated copper current collector, specifically:

[0061] Mixing 10 kg of conductive carbon black, 1 kg of conductive graphite, 1 kg of aluminum oxide, 40 kg of polydopamine-modified polyacrylic acid binder, and 168 kg of deionized water, adding 0.1 kg of aziridine crosslinking agent, stirring evenly, obtaining a nano-coating slurry, coating the obtained nano-coating slurry on a 6 μm copper current collector, and obtaining a high-adhesion nano-coated copper current collector with a coating thickness of 1 μm.

[0062] The preparation method of the cuprous iodide surface modified copper current collector is:

[0063] Washing the 6 μm copper current collector with ethanol and deionized water to remove dust and impurities on the surface, drying at room temperature, and obtaining a pretreated copper current collector.

[0064] Mix 15 kg of copper sulfate pentahydrate and 100 kg of deionized water, stir evenly, add 0.3 kg of 1-butyl-3-methyl-imidazole iodide, ultrasonic dispersion, form a mixed solution, put the pretreated copper current collector into the mixed solution, immerse at room temperature for 10 min, take out after the immersion is completed, wash with deionized water, dry, and obtain the cuprous iodide surface modified copper current collector.

[0065] The preparation method of the polydopamine-modified polyacrylic acid binder is:

[0066] Mix 8.5 kg of sodium hydroxide and 42.5 kg of deionized water, stir evenly, and obtain a sodium hydroxide solution. At 5°C, mix 15 kg of acrylic acid with the sodium hydroxide solution to obtain a sodium acrylate solution. Add 4 kg of acrylamide to the sodium acrylate solution, stir evenly, and obtain a sodium acrylate-acrylamide mixed solution. Mix 0.75 kg of methyl allyl polyoxyethylene ether and 20 kg of deionized water, stir evenly, and make it completely dissolved. Under nitrogen protection, add the sodium acrylate-acrylamide mixed solution, 6 kg of acrylonitrile, and 1.25 kg of ammonium persulfate. React at 70°C for 9 h at 300 rpm. After the reaction is completed, cool down, freeze-dry, wash with anhydrous ethanol, and suction filter to obtain a modified acrylic acid binder. Dissolve in 75 kg of deionized water to obtain a 25 wt% modified acrylic acid binder.

[0067] Mix 0.5 kg of dopamine with 9.5 kg of tris-hydroxymethyl aminomethane hydrochloride buffer solution, stir at room temperature for 8 h, and obtain a polydopamine solution. Mix the polydopamine solution with 30 kg of 25 wt% modified acrylic acid binder, stir evenly, and obtain a polydopamine-modified polyacrylic acid binder.

[0068] The following control experiments are based on Example 1, specifically Comparative Example 1 and Comparative Example 2, as described below:

[0069] Comparative Example 1: This comparative example relates to a preparation method of a high-adhesion nano-coated copper current collector. The difference from Example 1 is only that no anchoring agent alumina is added in the nano-coating slurry. Specifically:

[0070] Mix 10 kg of conductive carbon black, 1 kg of conductive graphite, 40 kg of 25 wt% modified polyacrylic acid binder, and 168 kg of deionized water, add 0.1 kg of aziridine type crosslinking agent, stir evenly, and obtain a nano-coating slurry. Coat the obtained nano-coating slurry on a 6 μm copper current collector, and the coating thickness is 1 μm, to obtain a high-adhesion nano-coated copper current collector.

[0071] Comparative Example 2: This comparative example relates to a preparation method of a high-adhesion nano-coated copper current collector. The difference from Example 1 is only that no aziridine type crosslinking agent is added in the nano-coating slurry. Specifically:

[0072] 10 kg of conductive carbon black, 1 kg of conductive graphite, 1 kg of alumina, 40 kg of 25 wt% modified polyacrylic acid binder and 168 kg of deionized water were mixed and stirred uniformly to obtain a nano-coating slurry. The obtained nano-coating slurry was coated on a 6 μm copper current collector to a thickness of 1 μm to obtain a high-adhesion nano-coating copper current collector.

[0073] Comparative Example 3: This comparative example relates to a method for preparing a high-adhesion nano-coating copper current collector, which differs from Example 1 only in that a polyacrylic acid binder is used in the nano-coating slurry. Specifically:

[0074] 10 kg of conductive carbon black, 1 kg of conductive graphite, 1 kg of alumina, 40 kg of 25 wt% polyacrylic acid binder and 168 kg of deionized water were mixed and stirred uniformly to obtain a nano-coating slurry. The obtained nano-coating slurry was coated on a 6 μm copper current collector to a thickness of 1 μm to obtain a high-adhesion nano-coating copper current collector.

[0075] Test experiments:

[0076] High-adhesion nano-coating copper current collectors were prepared according to the processes in Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, Example 7, Comparative Example 1, Comparative Example 2, Comparative Example 3, and a 6 μm copper current collector without nano-coating slurry was used as Comparative Example 4 for testing.

[0077] Peeling strength test:

[0078] The prepared 10 kinds of high-adhesion nano-coating copper current collectors and the 6 μm copper current collector without nano-coating slurry were coated with 90 μm thick negative electrode material, dried, and 20 mm wide and 200 mm long samples were taken from the center part of the electrode sheet. A 3M tape with a width of 20 mm was adhered to the center of a 50 mm x 100 mm steel plate. The sample and the tape were aligned and attached together at one end of the sample, the sample was reversed 180° at the other end and left a certain distance from the lower clamp of the universal material testing machine. The other end of the sample was attached to the upper clamp of the universal material testing machine. The sample was pulled at a speed of 100 mm / min until it was detached from the tape, the test was stopped, and the peeling strength of the sample was recorded.

[0079] After rolling the sample (the compaction density of the negative electrode material: 1.4 g / cm 3 ), the peeling strength was measured again using the above method.

[0080]

[0081] Conclusion: According to the test data, it can be seen that the peel strength of the high adhesion nano-coated copper current collector prepared by the preparation method of Example 1 is better than that of Comparative Example 1, Comparative Example 2 and Comparative Example 3 before and after rolling, and the peel strength of the copper current collector with high adhesion nano-coating is further enhanced after rolling.

[0082] It is apparent to a person skilled in the art that the present application is not limited to the details of the above-described exemplary embodiments, but can be implemented in other concrete forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, the scope of the present application being defined by the appended claims rather than the above description, and it is intended to embrace all changes and modifications that fall within the meaning and scope of equivalents of the claims.

Claims

1. A high-adhesion nano-coated copper current collector, characterized by: The copper current collector, the nanometer coating coated on the surface of the copper current collector, and a cuprous halide film deposited on the surface of the copper current collector; the nanometer coating comprises, by mass fraction, 6-22 parts of a conductive agent, 0.05-4 parts of an anchoring agent, 0.5-1.5 parts of a modified polyacrylic acid binder, and 0.01-0.1 parts of a crosslinking agent; The crosslinking agent is at least one of isocyanate, aziridine type curing agent, and epoxy type curing crosslinking agent; the anchoring agent is at least one of alumina ceramic particles and boehmite; The modified polyacrylic acid binder is prepared by the following steps: Sodium hydroxide and deionized water are mixed and stirred to obtain a sodium hydroxide solution, acrylic acid is mixed with the sodium hydroxide solution at 0-10°C to obtain a sodium acrylate solution, acrylamide is added to the sodium acrylate solution and stirred to obtain a sodium acrylate-acrylamide mixed solution, methyl alkenyl polyoxyethylene ether and deionized water are mixed and stirred to completely dissolve, the sodium acrylate-acrylamide mixed solution, acrylonitrile, and ammonium persulfate are added under nitrogen protection, and the mixture is reacted at 65-75°C and 250-350 rpm for 8-10 hours, after the reaction is completed, the mixture is cooled, freeze-dried, washed with anhydrous ethanol, and filtered to obtain the modified polyacrylic acid binder.

2. A high adhesion nano-coated copper current collector according to claim 1, characterized in that: The copper current collector is a cuprous bromide surface modified copper current collector, and the preparation method is as follows: The copper current collector is washed with ethanol and deionized water to remove dust and impurities on the surface, and dried at room temperature to obtain a pretreated copper current collector, copper sulfate pentahydrate and deionized water are mixed and stirred, dodecyltrimethylammonium bromide is added and ultrasonically dispersed to form a mixed solution, the pretreated copper current collector is placed in the mixed solution, and immersed at room temperature for 5-20 min, after the immersion is completed, the copper current collector is taken out, washed with deionized water, and dried to obtain the cuprous bromide surface modified copper current collector.

3. The high-adhesion nano-coated copper current collector of claim 1, wherein: The copper current collector is a cuprous iodide surface modified copper current collector, and the preparation method is as follows: The copper current collector is washed with ethanol and deionized water to remove dust and impurities on the surface, and dried at room temperature to obtain a pretreated copper current collector, copper sulfate pentahydrate and deionized water are mixed and stirred, 1-butyl-3-methyl imidazole iodide is added and ultrasonically dispersed to form a mixed solution, the pretreated copper current collector is placed in the mixed solution, and immersed at room temperature for 5-20 min, after the immersion is completed, the copper current collector is taken out, washed with deionized water, and dried to obtain the cuprous iodide surface modified copper current collector.

4. The high-adhesion nano-coated copper current collector of claim 1, wherein: The modified polyacrylic acid binder is a polydopamine-modified polyacrylic acid binder, and the preparation method is as follows: Dopamine and tris-hydroxymethyl aminomethane hydrochloride buffer solution are mixed and stirred at room temperature for 6-10 hours to obtain a polydopamine solution, the polydopamine solution and the modified polyacrylic acid binder are mixed to obtain the polydopamine-modified polyacrylic acid binder.

5. A method of making a high-adhesion nano-coated copper current collector according to claim 1, characterized in that: The preparation method is as follows: The conductive agent A, the conductive agent B, the anchoring agent, the modified polyacrylic acid binder, and deionized water are mixed, and the crosslinking agent is added and stirred to obtain a nanometer coating slurry, the nanometer coating slurry is coated on the copper current collector to obtain a high-adhesion nanometer coating copper current collector. The conductive agent includes a conductive agent A and a conductive agent B, the conductive agent A is at least one of conductive carbon black and carbon nanotube, the conductive agent B is at least one of conductive graphite and graphene, the particle size of the conductive agent B is 1-2 μm, and the mass ratio of the conductive agent A to the conductive agent B is (5-10):

1.

6. Use of the high-adhesion nano-coated copper current collector according to any one of claims 1-4 as a negative electrode material for a lithium ion battery.

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