Corrosion-resistant copper foil anode coating and method of making same

Abstract

The present application relates to a kind of corrosion-resistant copper foil anode coating and its preparation method, belong to electrolytic copper foil technical field.The coating is attached to the surface of titanium matrix, including three-layer structure: bottom layer is composed of and NiO;Intermediate layer is composed of and with form solid solution network pinning lattice, diffuse filling aperture makes porosity less than 5%;Surface layer is composed of and ternary solid solution and nitrogen-doped graphene.The present application realizes interface chemical bonding, intermediate layer dense barrier and surface layer high activity cooperation by three-layer functional gradient design, significantly improves the corrosion resistance and electrocatalytic activity of anode.

Description

Technical Field

[0001] This invention belongs to the field of electrolytic copper foil technology, and relates to a corrosion-resistant copper foil anodic coating and its preparation method. Background Technology

[0002] Electrolytic copper foil is a key basic material for the electronic information industry. In the process of preparing copper foil by electrolysis, the anode not only needs to have good electrocatalytic activity to reduce cell voltage and save energy, but also needs to have extremely strong corrosion resistance to resist the erosion of strong acidic copper sulfate electrolyte and the strong oxidizing environment brought about by oxygen evolution reaction under high current density.

[0003] While traditional ruthenium-based or iridium-based titanium anodes in the prior art have high electrocatalytic activity, they suffer from problems such as insufficient adhesion between the oxide coating and the titanium substrate, easy hydrolysis failure of the active layer, and difficulty in achieving both surface activity and corrosion resistance during long-term electrolysis.

[0004] Therefore, there is an urgent need to develop a corrosion-resistant copper foil anodic coating and its preparation method. Summary of the Invention

[0005] The purpose of this invention is to provide a corrosion-resistant copper foil anolyte coating and its preparation method, which has the characteristics of good electrocatalytic activity and corrosion resistance.

[0006] The objective of this invention can be achieved through the following technical solutions: A corrosion-resistant copper foil anodic coating, wherein the coating is adhered to the surface of a titanium substrate, and the coating has a three-layer structure, comprising, from bottom to top: The bottom layer is composed of IrO2 and NiO; An intermediate layer is composed of IrO2, Ta2O5, and ZrO2; wherein, Ta2O5 and IrO2 form a solid solution. The surface layer is composed of IrO2, RuO2, SnO2 and nitrogen-doped graphene; The method for preparing the nitrogen-doped graphene is as follows: Graphene oxide was placed in a plasma device and treated under a nitrogen atmosphere for 80-120 seconds at a nitrogen pressure of 120-150 Pa and a plasma power of 80-100 W to obtain graphene with a nitrogen doping content of 2-8 at%.

[0007] As a preferred embodiment of the present invention, the molar ratio of Ir to Ni in the bottom layer is 1:(0.3~0.8).

[0008] As a preferred embodiment of the present invention, the porosity of the intermediate layer is less than 5%, wherein the molar ratio of Ir, Ta and Zr is (5~7):(2~3):1.

[0009] As a preferred embodiment of the present invention, IrO2, RuO2 and SnO2 form a ternary solid solution in the surface layer, wherein the molar ratio of Ir, Ru and Sn is 1:(0.3~0.5):(0.1~0.2), and the mass of the nitrogen-doped graphene accounts for 0.1~3% of the total mass of the surface layer.

[0010] As a preferred embodiment of the present invention, the titanium matrix is ​​TA1 with a grain size of 6-9 and a Rockwell hardness of HRC50-60.

[0011] As a preferred embodiment of the present invention, the thickness ratio of the bottom layer, the intermediate layer and the top layer is (1~2):(2~3):1, and the total coating thickness is 5~20μm.

[0012] A method for preparing a corrosion-resistant copper foil anodic coating includes the following steps: S1: The titanium substrate was acid etched for 1-3 hours at a temperature of 70-80℃ using a solution of 0.5M oxalic acid and 0.5M hydrochloric acid mixed in a 1:1 volume ratio. The substrate was then washed with deionized water and dried to obtain the pretreated titanium substrate. S2: A precursor salt solution containing Ir and Ni is coated onto the surface of the pretreated titanium substrate, dried at 80~100℃, and then subjected to gradient heating heat treatment to form the bottom layer. S3: Coat the surface of the bottom layer with a precursor salt solution containing Ir, Ta and Zr, dry it at 80~100℃, and then heat treat it at 500~600℃ for 30~90min to form an intermediate layer. S4: Nitrogen-doped graphene is added to a precursor salt solution containing Ir, Ru and Sn, and reduced by ultraviolet light under a nitrogen atmosphere for 30-60 min. The resulting mixed solution is then coated onto the surface of the intermediate layer, dried at 80-100℃, heated to 380-480℃ at a rate of 10-20℃ / min, held for 5-15 min, and then cooled to room temperature at a rate of 5-10℃ / min to form the surface layer.

[0013] As a preferred embodiment of the present invention, the gradient heating heat treatment process parameters in S2 are set as follows: first, the temperature is increased to 300-350℃ at a rate of 2-5℃ / min and held for 10-20min; then, the temperature is increased to 450-550℃ at a rate of 1-2℃ / min and held for 30-60min.

[0014] As a preferred embodiment of the present invention, the light source used for ultraviolet light reduction in S4 is a mercury lamp with a power of 100~500W, an ultraviolet light wavelength of 254~365nm, and a controlled temperature of 20~40℃.

[0015] The bottom layer of this invention is composed of IrO2 and NiO. During heat treatment, NiO undergoes an in-situ solid-phase reaction with the naturally formed TiO2 layer on the titanium substrate surface, generating a solid solution transition layer. This eliminates the macroscopic physical interface between the traditional coating and the substrate, achieving chemical bonding and compositional gradient transition from metallic titanium to the oxide coating. This significantly reduces interfacial stress and substantially improves bonding strength. Furthermore, the molar ratio of Ir to Ni in the bottom layer is 1:0.3~0.8, ensuring sufficient electrocatalytic activity to support the upper layer while also ensuring sufficient NiO content to form a complete solid solution transition layer. The dense microstructure of the bottom layer effectively prevents electrolyte penetration into the titanium substrate, preventing passivation or hydrogen embrittlement during long-term operation. Simultaneously, the strong bonding and chemical stability of the bottom layer guarantee the functionality of the intermediate and surface layers, a prerequisite for the long-life operation of the coating.

[0016] The intermediate layer consists of , and Composition, in which, and Forming a solid solution Ion Occupation Lattice position effectively pins grain boundaries and defects, fundamentally suppressing... Hydrolysis failure occurs under acidic conditions. The molar ratio of Ir, Ta, and Zr is set to (5~7):(2~3):1. A continuous three-dimensional network framework is formed in the coating, spanning the entire thickness of the intermediate layer, to activate... Nanocrystals encapsulated within the network mesh physically block the entry channels of the electrolyte; further introducing Dispersed in nanocrystal form Porosity of the network skeleton and At grain boundaries, a pinning effect forms, which not only inhibits grain growth but also fills the tiny pores in the network framework, reducing the porosity of the intermediate layer to below 5%. This structure, combined with... Its extremely high chemical stability blocks the diffusion path of corrosive ions, thereby significantly extending the service life of the anode.

[0017] Surface layer uses It is a ternary system, and nitrogen-doped graphene has been introduced. , and With similar lattice constants, they can form a stable ternary solid solution under heat treatment conditions. The molar ratio of Ir, Ru, and Sn is controlled at 1:(0.3~0.5):(0.1~0.2), which balances... High initial activity and The long-term stability of SnO2; the coefficient of thermal expansion of SnO2 is different from that of the bottom and middle layers. By controlling its content and heat treatment temperature, the width and density of mud-crack-like microcracks formed on the surface during the cooling process can be precisely controlled. These controllable microcracks not only do not cause coating failure, but also greatly increase the electrochemical active specific surface area of ​​the electrode, providing more active sites for the oxygen evolution reaction.

[0018] The introduction of nitrogen-doped graphene further enhances surface performance. Graphene's high conductivity reduces surface resistance, while nitrogen doping strengthens the bonding with metal oxides. Its two-dimensional sheet structure covers the crack edges, preventing excessive crack propagation and protecting the underlying active material. Ultraviolet light reduction allows some Ir and Ru ions to be in situ loaded onto the graphene surface as 2-5 nm metal nanoparticles, forming a metal-graphene composite structure, further improving catalytic activity. The synergistic effect of the surface, intermediate, and bottom layers enables the anode to maintain high activity while achieving a longer lifespan.

[0019] The beneficial effects of this invention are: This invention achieves a comprehensive improvement in interfacial bonding strength, corrosion resistance, and electrocatalytic activity through the synergistic design of a three-layer functionally graded coating: the bottom layer utilizes NiO and the surface of the titanium substrate... A solid solution transition layer is generated, transforming the insulating passivation layer that causes coating peeling in traditional anodes into a chemically bonded gradient interface, thus solving the interface failure problem; the intermediate layer uses... , and Composite system, through and The formation of a solid solution pinning lattice inhibits hydrolysis, while Construct a continuous three-dimensional network skeleton. It disperses and fills the network pores in the form of nanocrystals, forming a dense layer with a porosity of less than 5%, thereby effectively blocking the diffusion path of corrosive ions and significantly improving lifespan; surface construction A ternary solid solution was formed and nitrogen-doped graphene was introduced, through... Controlled network cracks are formed to increase the active area. Nitrogen-doped graphene improves conductivity and protects crack edges. Combined with ultraviolet light reduction, metal nanoparticles are loaded in situ onto the graphene surface, further enhancing catalytic activity. Detailed Implementation

[0020] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0021] It should be noted that, unless otherwise specified, the present invention does not specifically limit the source of the raw materials used in the following embodiments. Commercially available products or products prepared by conventional preparation methods that are well known to those skilled in the art can be used. Experimental methods that do not specify specific conditions are all conventional methods and conventional conditions well known in the art.

[0022] Example 1

[0023] A method for preparing a corrosion-resistant copper foil anodic coating includes the following steps: S1: Select TA1 industrial pure titanium plate (grain size grade 7, Rockwell hardness HRC55), use a solution of 0.5M oxalic acid and 0.5M hydrochloric acid mixed in a 1:1 volume ratio, acid etch the titanium substrate at 75℃ for 2 hours, wash with deionized water and dry to obtain the pretreated titanium substrate. S2: Dissolve chloroiridic acid and nickel nitrate in a mixed solvent of n-butanol and isopropanol (volume ratio 1:1), with a molar ratio of Ir to Ni of 1:0.55. Apply the coating solution uniformly to the pretreated titanium substrate surface using a brush coating method, dry at 90℃ for 10 min, and then perform gradient heating heat treatment: first, heat to 320℃ at a rate of 3℃ / min and hold for 15 min; then heat to 500℃ at a rate of 1.5℃ / min and hold for 45 min. Repeat the coating-drying-heat treatment steps until the bottom layer thickness reaches approximately 4 μm. S3: Dissolve chloroiridic acid, tantalum pentachloride, and zirconium oxychloride octahydrate in a mixed solvent of n-butanol and isopropanol (volume ratio 1:1). The molar ratio of Ir, Ta, and Zr is 6:2.5:1. Apply the coating solution to the bottom layer surface using a brush coating method. After drying at 90°C, heat treat at 550°C for 60 min. Repeat the coating-drying-heat treatment steps until the intermediate layer thickness reaches approximately 8 μm and the intermediate layer porosity is 3.8%. S4: Dissolve chloroiridic acid, ruthenium trichloride, and tin tetrachloride in a mixed solvent of n-butanol and isopropanol (volume ratio 1:1), with a molar ratio of Ir, Ru, and Sn of 1:0.4:0.15. Add nitrogen-doped graphene to the above solution at a ratio of 1.5% of the total mass of the surface layer. Disperse ultrasonically for 30 min. Under a nitrogen atmosphere, perform ultraviolet light reduction for 45 min using a mercury lamp (300W light source power, 365nm ultraviolet wavelength) at a controlled temperature of 30℃. Then, coat the resulting mixed solution onto the surface of the intermediate layer. After drying at 90℃, heat to 430℃ at a rate of 15℃ / min and hold for 10 min. Then, cool to room temperature at a rate of 8℃ / min. Repeat the coating-drying-heat treatment steps until the surface layer thickness reaches approximately 4μm.

[0024] The preparation steps for nitrogen-doped graphene are as follows: 1g of graphene oxide was placed in a plasma device and treated for 100s under a nitrogen atmosphere with a nitrogen pressure of 135Pa and a plasma power of 90W to obtain graphene with a nitrogen doping content of 5at%.

[0025] Example 2

[0026] A method for preparing a corrosion-resistant copper foil anodic coating includes the following steps: S1: Select TA1 industrial pure titanium plate (grain size grade 7, Rockwell hardness HRC55), use a solution of 0.5M oxalic acid and 0.5M hydrochloric acid mixed in a 1:1 volume ratio, acid etch the titanium substrate at 78℃ for 2.5h, wash with deionized water and dry to obtain the pretreated titanium substrate. S2: Dissolve chloroiridic acid and nickel nitrate in a mixed solvent of n-butanol and isopropanol (volume ratio 1:1), with a molar ratio of Ir to Ni of 1:0.8. Apply the coating solution uniformly to the pretreated titanium substrate surface using a brush coating method. Dry at 90℃ for 10 min, followed by gradient heating heat treatment: first, heat to 350℃ at a rate of 5℃ / min and hold for 10 min; then heat to 550℃ at a rate of 2℃ / min and hold for 30 min. Repeat the coating-drying-heat treatment steps until the substrate thickness reaches approximately [missing value]. ; S3: Dissolve chloroiridic acid, tantalum pentachloride, and zirconium oxychloride octahydrate in a mixed solvent of n-butanol and isopropanol (volume ratio 1:1). The molar ratio of Ir, Ta, and Zr is 7:3:1. Apply the coating solution to the bottom layer surface using a brush coating method. After drying at 90°C, heat-treat at 600°C for 90 minutes. Repeat the coating-drying-heat-treatment steps until the intermediate layer thickness reaches approximately [missing value]. The porosity of the intermediate layer is 2.5%; S4: Dissolve chloroiridic acid, ruthenium trichloride, and tin tetrachloride in a mixed solvent of n-butanol and isopropanol (volume ratio 1:1), with a molar ratio of Ir, Ru, and Sn of 1:0.5:0.2. Add nitrogen-doped graphene at a ratio of 3% of the total surface layer mass to the above solution, and ultrasonically disperse for 30 min. Under a nitrogen atmosphere, perform ultraviolet light reduction for 60 min using a mercury lamp (light source power 500W, ultraviolet wavelength 365nm) at a controlled temperature of 40℃. Then, coat the resulting mixed solution onto the surface of the intermediate layer, dry at 90℃, and then heat to 480℃ at a rate of 20℃ / min, hold for 15 min, and then cool to room temperature at a rate of 10℃ / min. Repeat the coating-drying-heat treatment steps until the surface layer thickness reaches approximately [missing value]. .

[0027] The preparation steps for nitrogen-doped graphene are as follows: 1g of graphene oxide was placed in a plasma device and treated for 120s under a nitrogen atmosphere with a nitrogen pressure of 150Pa and a plasma power of 100W to obtain graphene with a nitrogen doping content of 8at%.

[0028] Example 3

[0029] A method for preparing a corrosion-resistant copper foil anodic coating includes the following steps: S1: Select TA1 industrial pure titanium plate (grain size grade 7, Rockwell hardness HRC55), use a solution of 0.5M oxalic acid and 0.5M hydrochloric acid mixed in a 1:1 volume ratio, acid etch the titanium substrate at 70℃ for 1h, wash with deionized water and dry to obtain the pretreated titanium substrate. S2: Dissolve chloroiridic acid and nickel nitrate in a mixed solvent of n-butanol and isopropanol (volume ratio 1:1), with a molar ratio of Ir to Ni of 1:0.3. Apply the coating solution uniformly to the pretreated titanium substrate surface using a brush coating method. Dry at 90℃ for 10 min, followed by gradient heating heat treatment: first, heat to 300℃ at a rate of 2℃ / min and hold for 20 min; then, heat to 450℃ at a rate of 1℃ / min and hold for 60 min. Repeat the coating-drying-heat treatment steps until the substrate thickness reaches approximately [missing value]. ; S3: Dissolve chloroiridic acid, tantalum pentachloride, and zirconium oxychloride octahydrate in a mixed solvent of n-butanol and isopropanol (volume ratio 1:1). The molar ratio of Ir, Ta, and Zr is 5:2:1. Apply the coating solution to the substrate surface using a brush coating method. After drying at 90°C, heat-treat at 500°C for 30 minutes. Repeat the coating-drying-heat-treatment steps until the intermediate layer thickness reaches approximately [missing value]. The porosity of the intermediate layer is 4.5%; S4: Dissolve chloroiridic acid, ruthenium trichloride, and tin tetrachloride in a mixed solvent of n-butanol and isopropanol (volume ratio 1:1), with a molar ratio of Ir, Ru, and Sn of 1:0.3:0.1. Add nitrogen-doped graphene to the above solution at a ratio of 0.1% of the total surface layer mass. Disperse ultrasonically for 30 min. Under a nitrogen atmosphere, perform ultraviolet light reduction for 30 min using a mercury lamp (100W light source, 365nm ultraviolet wavelength) at a controlled temperature of 20℃. Then, coat the resulting mixed solution onto the surface of the intermediate layer. After drying at 90℃, heat to 380℃ at a rate of 10℃ / min and hold for 5 min. Then cool to room temperature at a rate of 5℃ / min. Repeat the coating-drying-heat treatment steps until the surface layer thickness reaches approximately [missing value]. .

[0030] The preparation steps for nitrogen-doped graphene are as follows: 1g of graphene oxide was placed in a plasma device and treated for 80s under a nitrogen atmosphere with a nitrogen pressure of 120Pa and a plasma power of 80W to obtain graphene with a nitrogen doping content of 2at%.

[0031] Example 4

[0032] The difference between this embodiment and Embodiment 1 is that the molar ratio of Ir to Ni in the bottom coating liquid is 1:0.4, while the rest is the same as in Embodiment 1.

[0033] Example 5

[0034] The difference between this embodiment and Embodiment 1 is that the molar ratio of Ir, Ta, and Zr in the intermediate coating solution is 6:2:1, while the rest are the same as in Embodiment 1.

[0035] Example 6

[0036] The difference between this embodiment and Embodiment 1 is that the molar ratio of Ir, Ru, and Sn in the surface coating liquid is 1:0.35:0.12, while the rest are the same as in Embodiment 1.

[0037] Example 7

[0038] The difference between this embodiment and Embodiment 1 is that the amount of nitrogen-doped graphene added to the surface layer is adjusted to 0.5% of the total mass of the surface layer, while the rest is the same as in Embodiment 1.

[0039] Example 8

[0040] The difference between this embodiment and Embodiment 1 is that the amount of nitrogen-doped graphene added to the surface layer is adjusted to 2% of the total mass of the surface layer, while the rest is the same as in Embodiment 1.

[0041] Comparative Example 1 The difference between this comparative example and Example 1 is that nickel nitrate is not added to the bottom layer; otherwise, they are the same as in Example 1.

[0042] Comparative Example 2 The difference between this comparative example and Example 1 is that zirconium oxychloride octahydrate is not added to the intermediate layer; otherwise, they are the same as in Example 1.

[0043] Comparative Example 3 The difference between this comparative example and Example 1 is that no nitrogen-doped graphene is added to the surface layer; otherwise, they are the same as in Example 1.

[0044] Comparative Example 4 The difference between this comparative example and Example 1 is that tin tetrachloride is not added to the surface layer; otherwise, they are the same as in Example 1.

[0045] Comparative Example 5 The difference between this comparative example and Example 1 is that untreated graphene is used instead of nitrogen-doped graphene in the surface layer, while the rest is the same as in Example 1.

[0046] Comparative Example 6 The difference between this comparative example and Example 1 is that the ultraviolet light reduction step is omitted, while the rest is the same as Example 1.

[0047] Bonding force test Use a grid cutter to cut a grid on the coating surface with a blade spacing of 1mm, cutting to the depth penetrating the coating to the substrate. After cutting, gently sweep away the chips with a soft brush. Apply 3M 600 tape to the grid area and press it flat with an eraser to ensure full contact. Hold the free end of the tape at a 60° angle to the coating surface and peel it off smoothly within 0.5 to 1.0 seconds. Observe the coating peeling in the grid area under a magnifying glass and rate it.

[0048] Oxygen evolution overpotential test The test system is a three-electrode system: the working electrode is the anode sample to be tested, the counter electrode is a platinum sheet electrode, the reference electrode is a saturated calomel electrode, and the electrolyte is... Solution. The test procedure involves immersing the electrode under test in the electrolyte for 30 minutes to achieve a stable state, connecting it to an electrochemical workstation, and setting the scanning parameters as follows: scan range: 0.8~1.5 V vs. SCE, scan rate: 5 mV / s, test temperature: 25±1℃. The polarization curve is recorded, and the current density is read. The corresponding potential value is determined, and the oxygen evolution overpotential is calculated.

[0049] Enhanced lifespan testing Test conditions: Electrolyte: Solution, current density: Temperature: 40±1℃, Anode-cathode distance: 20 mm, Counter electrode: Stainless steel plate. Test procedure: Fix the anode sample to be tested relative to the stainless steel cathode, immerse it in the electrolyte, connect the DC power supply, and adjust the current to the set value. ), continuously record the change curve of the cell pressure over time, replace the electrolyte regularly (once every 24 hours), keep the test conditions stable, when the cell pressure increases by 5V from the initial value, it is considered that the anode has failed, and record the cumulative energization time.

[0050]

[0051] As can be seen from the examples and comparative data, the anodic coating prepared by the present invention has good adhesion, superior electrochemical activity and corrosion resistance, and has a longer enhanced life in strong acid and high current density environments.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention are still within the scope of the present invention.

Claims

1. A corrosion-resistant copper foil anodic coating, characterized in that, The coating is adhered to the surface of the titanium substrate, and the coating has a three-layer structure, comprising, from bottom to top: The bottom layer is composed of IrO2 and NiO, wherein NiO undergoes an in-situ solid-phase reaction with the TiO2 layer naturally formed on the surface of the titanium substrate during heat treatment to generate a solid solution transition layer. The intermediate layer is composed of IrO2, Ta2O5 and ZrO2; wherein, Ta2O5 and IrO2 form a solid solution, and ZrO2 is dispersed in the pores of the Ta2O5 network skeleton and at the grain boundaries of IrO2 in the form of nanocrystals, forming a pinning effect; The surface layer is composed of IrO2, RuO2, SnO2 and nitrogen-doped graphene, wherein IrO2, RuO2 and SnO2 form a stable ternary solid solution under heat treatment; The method for preparing the nitrogen-doped graphene is as follows: Graphene oxide was placed in a plasma device and treated under a nitrogen atmosphere for 80-120 seconds at a nitrogen pressure of 120-150 Pa and a plasma power of 80-100 W to obtain graphene with a nitrogen doping content of 2-8 at%.

2. The corrosion-resistant copper foil anodic coating according to claim 1, characterized in that, The molar ratio of Ir to Ni in the bottom layer is 1:(0.3~0.8).

3. The corrosion-resistant copper foil anodic coating according to claim 1, characterized in that, The porosity of the intermediate layer is less than 5%, wherein the molar ratio of Ir, Ta and Zr is (5~7):(2~3):

1.

4. The corrosion-resistant copper foil anodic coating according to claim 1, characterized in that, The surface layer contains IrO2, RuO2 and SnO2 forming a ternary solid solution, wherein the molar ratio of Ir, Ru and Sn is 1:(0.3~0.5):(0.1~0.2), and the nitrogen-doped graphene accounts for 0.1~3% of the total mass of the surface layer.

5. The corrosion-resistant copper foil anodic coating according to claim 1, characterized in that, The titanium matrix is ​​TA1 with a grain size of 6-9 and a Rockwell hardness of HRC50-60.

6. The corrosion-resistant copper foil anodic coating according to claim 1, characterized in that, The thickness ratio of the bottom layer, intermediate layer and top layer is (1~2):(2~3):1, and the total coating thickness is 5~20μm.

7. A method for preparing a corrosion-resistant copper foil anodic coating as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1: The titanium substrate was acid etched for 1-3 hours at a temperature of 70-80℃ using a solution of 0.5M oxalic acid and 0.5M hydrochloric acid mixed in a 1:1 volume ratio. The substrate was then washed with deionized water and dried to obtain the pretreated titanium substrate. S2: A precursor salt solution containing Ir and Ni is coated onto the surface of the pretreated titanium substrate, dried at 80~100℃, and then subjected to gradient heating heat treatment to form the bottom layer. S3: Coat the surface of the bottom layer with a precursor salt solution containing Ir, Ta and Zr, dry it at 80~100℃, and then heat treat it at 500~600℃ for 30~90min to form an intermediate layer. S4: Nitrogen-doped graphene is added to a mixed solvent of n-butanol and isopropanol containing precursor salts of Ir, Ru and Sn, and subjected to ultraviolet light reduction for 30-60 min under nitrogen atmosphere protection. The resulting mixed solution is then coated onto the surface of the intermediate layer, dried at 80-100℃, heated to 380-480℃ at a rate of 10-20℃ / min, held for 5-15 min, and then cooled to room temperature at a rate of 5-10℃ / min to form the surface layer.

8. The method for preparing a corrosion-resistant copper foil anodic coating according to claim 7, characterized in that, The gradient heating heat treatment process parameters in S2 are set as follows: first, the temperature is increased to 300-350℃ at a rate of 2-5℃ / min and held for 10-20min; then, the temperature is increased to 450-550℃ at a rate of 1-2℃ / min and held for 30-60min.

9. The method for preparing a corrosion-resistant copper foil anodic coating according to claim 7, characterized in that, The light source used for ultraviolet light reduction in S4 is a mercury lamp with a power of 100~500W, an ultraviolet wavelength of 254~365nm, and a controlled temperature of 20~40℃.

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