阅读说明：本技术 塑料膜基铜箔的制造方法及其铜箔 (Method for manufacturing plastic film-based copper foil and copper foil thereof ) 是由 李金明 于 2021-07-08 设计创作，主要内容包括：本发明提供一种塑料膜基铜箔的制造方法及其铜箔,其中铜箔的制造方法包括步骤：(1)于基材的上下表面通过真空溅射法形成铜镍合金层；(2)将铜镍合金层进行除油、酸洗以去除部分铜而形成镍微孔；(3)于铜镍合金层的表面上形成电镀铜层同时填充镍微孔；(4)于电镀铜层上电镀锌镍合金层以形成抗氧化层。采用电镀铜层不存在物理堆积、不结晶的现象,故导电性佳,且于电镀铜层形成前将铜镍合金层除油、酸洗以去除部分铜而形成镍微孔,在电镀铜时,不仅会于铜镍合金层上形成电镀铜层,同时还会填充镍微孔,故电镀铜层和铜镍合金层之间的结合力大大提高,于电镀铜层上电镀锌镍合金层以形成抗氧化层时,抗氧化层会随电镀铜层而附着于铜镍合金层上,故提高耐折性能。(The invention provides a method for manufacturing a plastic film-based copper foil and a copper foil thereof, wherein the method for manufacturing the copper foil comprises the following steps: (1) forming a copper-nickel alloy layer on the upper and lower surfaces of the base material by a vacuum sputtering method; (2) degreasing and pickling the copper-nickel alloy layer to remove part of copper to form nickel micropores; (3) forming an electroplated copper layer on the surface of the copper-nickel alloy layer and filling the nickel micropores; (4) and electroplating a zinc-nickel alloy layer on the electroplated copper layer to form an oxidation resistant layer. The copper-nickel alloy layer is degreased and pickled to remove partial copper to form nickel micropores before the copper electroplating layer is formed, the copper electroplating layer is formed on the copper-nickel alloy layer and the nickel micropores are filled simultaneously during copper electroplating, so that the binding force between the copper electroplating layer and the copper-nickel alloy layer is greatly improved, and the oxidation resistant layer is attached to the copper-nickel alloy layer along with the copper electroplating layer when the zinc-nickel alloy layer is electroplated on the copper electroplating layer to form the oxidation resistant layer, so that the folding resistance is improved.)

1. A method for manufacturing a plastic film-based copper foil, comprising the steps of:

(1) forming a copper-nickel alloy layer on the upper and lower surfaces of the base material by a vacuum sputtering method;

(2) degreasing and pickling the copper-nickel alloy layer to remove part of copper to form nickel micropores;

(3) forming an electroplated copper layer on the surface of the copper-nickel alloy layer and filling the nickel micropores;

(4) and electroplating a zinc-nickel alloy layer on the electroplated copper layer to form an oxidation resistant layer.

2. The process for producing a plastic film-based copper foil according to claim 1 wherein the weight percentage of copper in the layer of copper-nickel alloy is greater than 0% and not greater than 95%.

3. The method of claim 1 wherein the pickling is carried out by immersing the copper foil in 10-20% hydrochloric acid or 0.5-20% dilute sulfuric acid for 0.5-10 min.

4. The method of claim 1 wherein the copper-nickel alloy layer is acid roughened prior to the formation of the electroplated copper layer in step (3).

5. The method of manufacturing a plastic film-based copper foil according to claim 4, wherein the copper electroplating layer is formed by an electroplating process comprising: the electroplating solution comprises copper sulfate and an additive, wherein the copper content in the electroplating solution is 60-100 g/L, the acid content in the electroplating solution is 50-120 g/L, and the electroplating is carried out for 1-10 min by adopting a current density of 2-10 ASD.

6. The method of manufacturing a plastic film-based copper foil according to claim 4, wherein the copper electroplating layer is formed by an electroplating process comprising: the electroplating solution comprises copper pyrophosphate and an additive, wherein the content of copper in the electroplating solution is 20-50 g/L, the content of total pyrophosphate ions is 140-425 g/L, and the electroplating is carried out for 10-40 min by adopting a current density of 1-4A/d square meter.

7. The method of claim 1 wherein step (4) is carried out by roughening the copper plating layer, washing with water, and plating a zinc-nickel alloy layer to form a nano oxidation resistant layer.

8. The plastic film-based copper foil according to any one of claims 1 to 7, which is characterized by comprising an upper oxidation resistant layer, an upper copper-plated layer, an upper copper-nickel alloy layer, a base material, a lower copper-nickel alloy layer, a lower copper-plated layer, and a lower oxidation resistant layer in this order from the top.

9. The plastic film-based copper foil of claim 8 wherein the substrate has a thickness of 2 to 50 μm, the upper and lower copper-nickel alloy layers have a uniform thickness of 5 to 50nm, the upper and lower copper-plated layers have a uniform thickness of 0.5 to 30 μm, and the upper and lower oxidation resistant layers have a uniform thickness of 100nm to 1 μm.

10. The plastic film-based copper foil of claim 8 wherein the substrate is selected from the group consisting of PET, PO, PEN, LCP, PA, PI and PS, and the upper and lower oxidation resistant layers are zinc-nickel alloy layers.

Technical Field

The invention relates to the technical field of materials, in particular to a manufacturing method of a plastic film-based copper foil and the copper foil.

Background

With the development of a highly information-oriented society, a mobile phone is rapidly popularized as a notebook computer product, and since people pay attention to environmental protection and energy conservation, the development of electric vehicles is receiving much attention, and a lithium ion battery is the most ideal energy source as a power source of the above products. The copper foil is used as a main material of a negative current collector of the lithium ion battery, and the development of the production technology and the quality of the performance directly influence the manufacturing process, the performance and the production cost of the lithium ion battery.

At present, a common copper foil is formed by forming a metal seed layer on the upper surface and the lower surface of a plastic substrate, then forming a copper layer, and finally forming an oxidation resistant layer on the surfaces of the two copper layers, wherein the seed layer can improve the adhesion of the copper layer on the plastic substrate to a certain extent, and the oxidation resistant layer can prevent the copper layer from being corroded by electrolyte when the copper foil is used as an anode current collector, so that the service life of a battery is shortened. In the prior art, a copper layer is formed by a sputtering method generally, so that physical accumulation of particles is caused, the particles are not crystallized, the conductivity of the copper foil is poor, and the copper foil is not folding-resistant, meanwhile, the thickness of the copper layer is thicker than that of a seed layer, and the adhesion of the copper layer formed by sputtering on the seed layer is limited, so that the copper layer is easy to fall off when an anti-oxidation layer is formed on the surface of the copper layer, and the use of the copper foil is greatly limited.

In view of the above, there is a need for a new copper foil or a method for manufacturing a copper foil to solve the above-mentioned problems.

Disclosure of Invention

The invention aims to provide a method for manufacturing a plastic film-based copper foil and the copper foil thereof, wherein the plastic film-based copper foil manufactured by the method has strong adhesion of a copper layer, and the copper foil has good folding resistance and electrical conductivity.

In order to achieve the above object, according to another aspect of the present invention, there is provided a method for manufacturing a plastic film-based copper foil, comprising the steps of:

(1) forming a copper-nickel alloy layer on the upper and lower surfaces of the base material by a vacuum sputtering method;

(2) degreasing and pickling the copper-nickel alloy layer to remove part of copper to form nickel micropores;

(3) forming an electroplated copper layer on the surface of the copper-nickel alloy layer and filling the nickel micropores;

(4) and electroplating a zinc-nickel alloy layer on the electroplated copper layer to form an oxidation resistant layer.

Compared with the prior art, the manufacturing method of the invention replaces the traditional sputtered copper layer with the electroplated copper layer, so the physical accumulation and non-crystallization phenomena do not exist, and the electrical conductivity is good. Therefore, the copper foil manufactured by the manufacturing method has good electrical conductivity and folding endurance.

The invention provides a plastic film-based copper foil, which comprises an upper oxidation resistant layer, an upper copper-nickel alloy layer, a base material, a lower copper-nickel alloy layer and a lower oxidation resistant layer from top to bottom in sequence. The copper foil has strong adhesion between the upper electroplated layer and the upper copper-nickel alloy layer and strong adhesion between the lower electroplated layer and the lower copper-nickel alloy layer, so the copper foil has good folding resistance and can expand the application range.

Detailed Description

The method for manufacturing a plastic film-based copper foil of the present invention includes the steps of:

(1) forming a copper-nickel alloy layer on the upper and lower surfaces of the base material by a vacuum sputtering method;

(2) degreasing and pickling the copper-nickel alloy layer to remove part of copper to form nickel micropores;

(3) forming an electroplated copper layer on the surface of the copper-nickel alloy layer far away from the base material and filling the nickel micropores;

(4) and electroplating a zinc-nickel alloy layer on the electroplated copper layer to form an oxidation resistant layer.

The material of the base material in the step (1) can be one selected from PET, PO, PEN, LCP, PA, PI and PS, the thickness can be 2-50 μm, the porosity is less than 10%, and the thickness of the copper-nickel alloy layer is 5-50 nm. Before vacuum sputtering, the base material can be subjected to corona treatment, and then vacuum sputtering is carried out in a vacuum sputtering coating machine to form a copper-nickel alloy layer, wherein the copper-nickel alloy layer is a copper-nickel alloy layer, the weight percentage of copper in the copper-nickel alloy layer is more than 0 and less than or equal to 95%, the copper-nickel alloy layer adopts copper and nickel as targets, the weight percentage of copper is 0-95% and not equal to 0, and the weight percentage of nickel is 5-100% and not equal to 100%.

And (3) cleaning the oil removed in the step (2) by using alkali liquor, wherein the alkali liquor can be sodium carbonate or sodium bicarbonate, adding a surfactant such as sodium dodecyl benzene sulfonate and the like, cleaning for 1-5 min by using the alkali liquor, then washing by using water, and then carrying out acid washing. The pickling is to soak the copper alloy layer for 0.5 to 10min by using 10 to 20 percent hydrochloric acid or 0.5 to 20 percent dilute sulfuric acid, and the pickling can lead part of copper components on the surface of the copper-nickel alloy layer to be corroded and react to form nickel micropores.

In the step (3), the copper-nickel alloy layer is firstly subjected to acid pickling coarsening to form a rough surface, then electroplating is carried out, an electroplating solution comprises copper sulfate and an additive, the copper content in the electroplating solution is 60-100 g/L, the acid content is 50-120 g/L, and electroplating is carried out for 1-10 min by adopting a current density of 2-10 ASD. Wherein the additive can be brightener, leveling agent, etc. Specifically, the electroplating solution can be 80g/L copper sulfate, 160g/L sulfuric acid, 0.01 g/L3-mercapto-1-propyl sodium sulfonate, 0.01g/L sodium polydithio dipropyl sulfonate and 0.02g/L polyethylene glycol aqueous solution, and of course, the invention can also adopt other electroplating methods for electroplating. The electroplating technology adopted by the electroplated copper layer is as follows: the electroplating solution comprises copper pyrophosphate and an additive, wherein the content of copper in the electroplating solution is 20-50 g/L, the content of total pyrophosphate ions is 140-425 g/L, and the electroplating is carried out for 10-40 min by adopting a current density of 1-4A/d square meter. The copper layer formed by electroplating can fill the nickel micropores and form an electroplated copper layer on the surface of the nickel layer, and the thickness of the electroplated copper layer is 0.5-30 mu m.

In the step (4), the electroplated copper layer is subjected to roughening treatment and then washed, and then the nano oxidation resistant layer is formed through the zinc-nickel alloy layer. The coarsening treatment process comprises the following steps: the roughening solution is 10-50 g/L Cu²⁺30-90 g/L of H₂SO₄An appropriate amount of additive, and a current density of 10-60A/dm²The temperature is room temperature, and the plating time is 3-5 s. The nano oxidation resistant layer can prevent the copper layer from being corroded by electrolyte to reduce the service life of the battery when the copper foil is used as an anode current collector. The electroplating solution adopted by the electroplating zinc-nickel alloy layer comprises zinc chloride, nickel chloride and an auxiliary agent, and the electroplating is carried out for 5-20 seconds by adopting the current density of 2-4 ASD. Specifically, the electroplating solution can be 50-65 g/L of zinc chloride, 140g/L of nickel chloride, 220-230 g/L of ammonium chloride, 25g/L of triethanolamine and a proper amount of ammonia water, and other zinc-nickel containing solutions can be adopted for electroplating. And finally, carrying out three-stage washing and drying.

The plastic film-based copper foil comprises an upper oxidation resistant layer, an upper copper-nickel alloy layer, a base material, a lower copper-nickel alloy layer and a lower oxidation resistant layer which are arranged in sequence from top to bottom. The upper oxidation resistant layer and the lower oxidation resistant layer can prevent the upper copper plating layer and the lower copper plating layer from being corroded by electrolyte, the upper copper plating layer and the lower copper plating layer are not only respectively electroplated on the surfaces of the upper copper-nickel alloy layer and the lower copper-nickel alloy layer, but also filled in nickel micropores embedded in the upper copper plating layer and the lower copper plating layer, so that the surface adhesion of the upper copper plating layer and the lower copper plating layer on the upper copper-nickel alloy layer and the lower copper-nickel alloy layer is strong, and the binding force between the upper copper plating layer and the base material and the binding force between the lower copper plating layer and the base material can be improved by the upper copper-nickel alloy layer and the lower copper-nickel alloy layer. The base material can be selected from one of PET (polyethylene terephthalate), PO (polyolefin), PEN (polyethylene naphthalate), LCP (polyarylate), PA (polyamide), PI (polyimide) and PS (polystyrene), the thickness can be 2-50 mu m, and the porosity is less than 10%. The upper copper-nickel alloy layer and the lower copper-nickel alloy layer are consistent in thickness and 5-50 nm, and the upper copper-nickel alloy layer and the lower copper-nickel alloy layer are copper-nickel alloy layers. The thickness of the upper copper plating layer is consistent with that of the lower copper plating layer and is 0.5-30 mu m. The thickness of the upper oxidation resisting layer is consistent with that of the lower oxidation resisting layer and is 100 nm-1 mu m, and the upper oxidation resisting layer and the lower oxidation resisting layer are zinc-nickel alloy layers.

The copper foil and the method for producing the same of the present invention will be described in detail with reference to specific examples.

Example 1

A plastic film-based copper foil is used for an anode current collector of a battery and comprises an upper oxidation resisting layer, an upper copper-nickel alloy layer, a base material, a lower copper-nickel alloy layer and a lower oxidation resisting layer which are arranged from top to bottom in sequence, wherein the upper oxidation resisting layer and the lower oxidation resisting layer are zinc-nickel alloy layers and are 200nm thick, the upper copper-nickel alloy layer and the lower copper-nickel alloy layer are 5 mu m thick, the upper copper-nickel alloy layer and the lower copper-nickel alloy layer are 10nm thick, the base material is PET and is 10 mu m thick.

The preparation method of the copper foil comprises the following steps:

(1) performing corona treatment on the upper and lower surfaces of a PET (polyethylene terephthalate) base material, and then forming an upper copper-nickel alloy layer and a lower copper-nickel alloy layer by using copper and nickel (the weight ratio is 90:10) as targets through a vacuum sputtering method;

(2) soaking the upper copper-nickel alloy layer and the lower copper-nickel alloy layer for 2min by using a mixed solution of sodium carbonate (50g/L) and sodium dodecyl benzene sulfonate (1g/L) as an alkali liquor to remove oil, then washing with water, and then soaking the upper copper-nickel alloy layer and the lower copper-nickel alloy layer for 2min by using dilute sulfuric acid with the concentration of 10% to wash with acid so as to corrode part of copper components on the surfaces of the upper copper-nickel alloy layer and the lower copper-nickel alloy layer to form nickel micropores;

(3) carrying out acid washing and coarsening on the upper copper-nickel alloy layer and the lower copper-nickel alloy layer to form rough surfaces, and then carrying out electroplating, wherein an electroplating solution is an aqueous solution of 80g/L copper sulfate, 160g/L sulfuric acid, 0.01 g/L3-mercapto-1-propyl sodium sulfonate, 0.01g/L sodium polydithio-dipropyl sulfonate and 0.02g/L polyethylene glycol, the current density of 6ASD is adopted for electroplating for 2min, and an upper copper plating layer and a lower copper plating layer are formed on the surfaces of the upper copper-nickel alloy layer and the lower copper-nickel alloy layer far away from the base material and are filled with nickel micropores;

(4) carrying out roughening treatment on the upper copper plating layer and the lower copper plating layer, wherein the roughening treatment process comprises the following steps: the roughening solution was 30g/L of Cu²⁺40g/L of H₂SO₄The current density is 60A/dm²The temperature is room temperature, the plating time is 5s, the nano oxidation resistant layer is formed by performing coarsening treatment and then water washing, the nano oxidation resistant layer is formed by electroplating a zinc-nickel alloy layer, the electroplating solution comprises 65g/L of zinc chloride, 140g/L of nickel chloride, 220g/L of ammonium chloride, 25g/L of triethanolamine and a proper amount of ammonia water, the zinc-nickel alloy layer is formed on the electroplated copper layer by electroplating for 20 seconds at the temperature of 35 ℃ and the pH value of 5.35-5.60 by adopting the current density of 6ASD, and finally, three-stage water washing and drying are performed.

Example 2

A plastic film-based copper foil is used for an anode current collector of a battery and comprises an upper oxidation resisting layer, an upper copper-nickel alloy layer, a base material, a lower copper-nickel alloy layer and a lower oxidation resisting layer which are arranged from top to bottom in sequence, wherein the upper oxidation resisting layer and the lower oxidation resisting layer are zinc-nickel alloy layers and are 200nm thick, the upper copper-nickel alloy layer and the lower copper-nickel alloy layer are 5 mu m thick, the upper copper-nickel alloy layer and the lower copper-nickel alloy layer are 10nm thick, the base material is PET and is 10 mu m thick.

The preparation method of the copper foil comprises the following steps:

(1) performing corona treatment on the upper and lower surfaces of a PET (polyethylene terephthalate) base material, and then forming an upper copper-nickel alloy layer and a lower copper-nickel alloy layer by using copper and nickel (the weight ratio is 90:10) as targets through a vacuum sputtering method;

(2) soaking the upper copper-nickel alloy layer and the lower copper-nickel alloy layer for 2min by using a mixed solution of sodium carbonate (50g/L) and sodium dodecyl benzene sulfonate (1g/L) as an alkali liquor to remove oil, then washing with water, and then soaking the upper copper-nickel alloy layer and the lower copper-nickel alloy layer for 2min by using hydrochloric acid with the concentration of 15% to wash with acid so as to corrode part of copper components on the surfaces of the upper copper-nickel alloy layer and the lower copper-nickel alloy layer to form nickel micropores;

(3) carrying out acid washing and coarsening on the upper copper-nickel alloy layer and the lower copper-nickel alloy layer to form rough surfaces, and then carrying out electroplating, wherein an electroplating solution is an aqueous solution of 80g/L copper sulfate, 160g/L sulfuric acid, 0.01 g/L3-mercapto-1-propyl sodium sulfonate, 0.01g/L sodium polydithio-dipropyl sulfonate and 0.02g/L polyethylene glycol, the current density of 6ASD is adopted for electroplating for 2min, and an upper copper plating layer and a lower copper plating layer are formed on the surfaces of the upper copper-nickel alloy layer and the lower copper-nickel alloy layer far away from the base material and are filled with nickel micropores;

(4) carrying out roughening treatment on the upper copper plating layer and the lower copper plating layer, wherein the roughening treatment process comprises the following steps: the roughening solution was 30g/L of Cu²⁺40g/L of H₂SO₄The current density is 60A/dm²The temperature is room temperature, the plating time is 5s, the nano oxidation resistant layer is formed by performing coarsening treatment and then water washing, the nano oxidation resistant layer is formed by electroplating a zinc-nickel alloy layer, the electroplating solution comprises 65g/L of zinc chloride, 140g/L of nickel chloride, 220g/L of ammonium chloride, 25g/L of triethanolamine and a proper amount of ammonia water, the zinc-nickel alloy layer is formed on the electroplated copper layer by electroplating for 20 seconds at the temperature of 35 ℃ and the pH value of 5.35-5.60 by adopting the current density of 6ASD, and finally, three-stage water washing and drying are performed.

Example 3

A plastic film-based copper foil is used for an anode current collector of a battery and comprises an upper oxidation resisting layer, an upper copper-nickel alloy layer, a base material, a lower copper-nickel alloy layer and a lower oxidation resisting layer which are arranged from top to bottom in sequence, wherein the upper oxidation resisting layer and the lower oxidation resisting layer are zinc-nickel alloy layers and are 300nm thick, the upper copper-nickel alloy layer and the lower copper-nickel alloy layer are 5 mu m thick, the upper copper-nickel alloy layer and the lower copper-nickel alloy layer are 10nm thick, the base material is PET and is 12 mu m thick.

The preparation method of the copper foil comprises the following steps:

(1) performing corona treatment on the upper and lower surfaces of a PET (polyethylene terephthalate) base material, and then forming an upper copper-nickel alloy layer and a lower copper-nickel alloy layer by using copper and nickel (the weight ratio is 50:50) as targets through a vacuum sputtering method;

(2) soaking the upper copper-nickel alloy layer and the lower copper-nickel alloy layer for 3min by using a mixed solution of sodium bicarbonate (45g/L) and sodium dodecyl benzene sulfonate (1g/L) as an alkali liquor to remove oil, then washing with water, and then soaking the upper copper-nickel alloy layer and the lower copper-nickel alloy layer for 2min by using dilute sulfuric acid with the concentration of 20% to wash with acid so as to corrode part of copper components on the surfaces of the upper copper-nickel alloy layer and the lower copper-nickel alloy layer to form nickel micropores;

(3) carrying out acid washing and coarsening on the upper copper-nickel alloy layer and the lower copper-nickel alloy layer to form rough surfaces, and then carrying out electroplating, wherein an electroplating solution is an aqueous solution of 80g/L copper sulfate, 160g/L sulfuric acid, 0.01 g/L3-mercapto-1-propyl sodium sulfonate, 0.01g/L sodium polydithio-dipropyl sulfonate and 0.02g/L polyethylene glycol, the current density of 6ASD is adopted for electroplating for 2min, and an upper copper plating layer and a lower copper plating layer are formed on the surfaces of the upper copper-nickel alloy layer and the lower copper-nickel alloy layer far away from the base material and are filled with nickel micropores;

(4) carrying out roughening treatment on the upper copper plating layer and the lower copper plating layer, wherein the roughening treatment process comprises the following steps: the roughening solution was 30g/L of Cu²⁺40g/L of H₂SO₄The current density is 60A/dm²The temperature is room temperature, the plating time is 5s, the nano oxidation resistant layer is formed by performing coarsening treatment and then water washing, the nano oxidation resistant layer is formed by electroplating a zinc-nickel alloy layer, the electroplating solution comprises 60g/L of zinc chloride, 140g/L of nickel chloride, 225g/L of ammonium chloride, 25g/L of triethanolamine and a proper amount of ammonia water, the zinc-nickel alloy layer is formed on the electroplated copper layer by electroplating for 20 seconds at the temperature of 38 ℃ and the pH value of 5.35-5.60 by adopting the current density of 6ASD, and finally, three-stage water washing and drying are performed.

Example 4

A plastic film-based copper foil is used for an anode current collector of a battery and comprises an upper oxidation resisting layer, an upper copper-nickel alloy layer, a base material, a lower copper-nickel alloy layer and a lower oxidation resisting layer which are arranged from top to bottom in sequence, wherein the upper oxidation resisting layer and the lower oxidation resisting layer are zinc-nickel alloy layers and are 200nm thick, the upper copper-nickel alloy layer and the lower copper-nickel alloy layer are 3 mu m thick, the upper copper-nickel alloy layer and the lower copper-nickel alloy layer are 10nm thick, the base material is PET and is 10 mu m thick.

The preparation method of the copper foil comprises the following steps:

(1) performing corona treatment on the upper and lower surfaces of a PET (polyethylene terephthalate) base material, and then forming an upper copper-nickel alloy layer and a lower copper-nickel alloy layer by using copper and nickel (the weight ratio is 95:5) as targets through a vacuum sputtering method;

(2) soaking the upper copper-nickel alloy layer and the lower copper-nickel alloy layer for 2min by using a mixed solution of sodium carbonate (50g/L) and sodium dodecyl benzene sulfonate (1g/L) as an alkali liquor to remove oil, then washing with water, and then soaking the upper copper-nickel alloy layer and the lower copper-nickel alloy layer for 2min by using dilute sulfuric acid with the concentration of 10% to wash with acid so as to corrode part of copper components on the surfaces of the upper copper-nickel alloy layer and the lower copper-nickel alloy layer to form nickel micropores;

(3) carrying out acid washing and coarsening on the upper copper-nickel alloy layer and the lower copper-nickel alloy layer to form rough surfaces, and then carrying out electroplating, wherein an electroplating solution is an aqueous solution of 66g/L copper sulfate, 100g/L sulfuric acid, 0.01 g/L3-mercapto-1-propyl sodium sulfonate, 0.01g/L sodium polydithio-dipropyl sulfonate and 0.02g/L polyethylene glycol, the current density of 8ASD is adopted for electroplating for 2min, and an upper copper plating layer and a lower copper plating layer are formed on the surfaces of the upper copper-nickel alloy layer and the lower copper-nickel alloy layer far away from the base material and are filled with nickel micropores;

(4) carrying out roughening treatment on the upper copper plating layer and the lower copper plating layer, wherein the roughening treatment process comprises the following steps: the roughening solution is 50g/L Cu²⁺40g/L of H₂SO₄The current density is 60A/dm²The temperature is room temperature, the plating time is 3s, the nano oxidation resistant layer is formed by performing coarsening treatment and then water washing, the nano oxidation resistant layer is formed by electroplating a zinc-nickel alloy layer, the electroplating solution comprises 65g/L of zinc chloride, 140g/L of nickel chloride, 220g/L of ammonium chloride, 25g/L of triethanolamine and a proper amount of ammonia water, the zinc-nickel alloy layer is formed on the electroplated copper layer by electroplating for 20 seconds at the temperature of 35 ℃ and the pH value of 5.35-5.60 by adopting the current density of 6ASD, and finally, three-stage water washing and drying are performed.

Comparative example 1

A plastic film-based copper foil is used for an anode current collector of a battery and comprises an upper oxidation resisting layer, an upper copper-nickel alloy layer, a base material, a lower copper-nickel alloy layer, a lower copper layer and a lower oxidation resisting layer which are arranged from top to bottom in sequence, wherein the upper oxidation resisting layer and the lower oxidation resisting layer are zinc-nickel alloy layers and are 200nm thick, the upper copper layer and the lower copper layer are 5 mu m thick, the upper copper-nickel alloy layer and the lower copper-nickel alloy layer are 10nm thick, and the base material is PET and is 10 mu m thick.

The preparation method of the copper foil comprises the following steps:

1. performing corona treatment on the upper and lower surfaces of a PET (polyethylene terephthalate) base material, and then forming an upper copper-nickel alloy layer and a lower copper-nickel alloy layer by using copper and nickel (the weight ratio is 90:10) as targets through a vacuum sputtering method;

2. carrying out acid cleaning and coarsening on the upper copper-nickel alloy layer and the lower copper-nickel alloy layer to form rough surfaces, then carrying out vacuum sputtering by taking copper as a target to form an upper copper layer and a lower copper layer;

3. and then electroplating a zinc-nickel alloy layer to form a nano oxidation resistant layer, wherein the electroplating solution comprises 65g/L of zinc chloride, 140g/L of nickel chloride, 220g/L of ammonium chloride, 25g/L of triethanolamine and a proper amount of ammonia water, electroplating for 20 seconds at the temperature of 35 ℃ and the pH value of 5.35-5.60 by adopting the current density of 6ASD to form the electroplated zinc-nickel alloy layer on the electroplated copper layer, and finally carrying out three-stage washing and drying.

The copper foils of examples 1 to 4 and comparative example 1 were subjected to conductivity and folding endurance tests under the following test conditions, and the results are shown in table 1.

And (3) testing conditions are as follows: the electrical conductivity (% IACS) at 25 ℃ was measured by the 4-terminal method in accordance with JIS H0505-1975 method for measuring the electrical resistivity and conductivity of nonferrous metal materials. The folding endurance times are tested by adopting a Sacheng NZ-01 copper foil folding endurance tester.

Examples	Conductivity/% IACS	Number of times of folding
			Example 1	100	2900 times
Example 2	101	2850 times
			Example 3	95	3000 times (twice)
Example 4	90	2300 times
			Comparative example 1	84	2100 times

As can be seen from the results in table 1, the electrical conductivity of the copper layer formed by electroplating according to the present invention is higher than that of the plastic film-based copper foil formed by vacuum sputtering according to comparative example 1, and the folding endurance is better because the copper layer formed by electroplating does not have the physical accumulation and non-crystallization phenomenon, so the electrical conductivity is good, and the copper-nickel alloy layer is degreased and pickled to remove part of copper before the copper layer is electroplated to form nickel micropores.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.