A multi-walled carbon nanotube additive for double-sided smooth high-strength ultra-thin electrolytic copper foil

Abstract

The application discloses a kind of double-sided smooth high-strength ultra-thin electrolytic copper foil with multi-walled carbon nanotube additive, the concentration of each component in copper sulfate solution is as follows: multi-walled carbon nanotube 0.22-0.48 g / L, hydrochloric acid 28-35 mg / L, polydithiopropane sulfonic acid sodium 2.6-5.2 mg / L, collagen 6-12 mg / L, polyethylene glycol 4.5-6.8 mg / L, hydroxyethyl cellulose 3.5-4.8 mg / L;Among them, the number of walls of the multi-walled carbon nanotube is an integer in 3-9;The length:diameter of the multi-walled carbon nanotube=(110-125):(1-1.5).The copper foil prepared by using the additive of the application significantly improves the surface roughness, effectively improves the electrical conductivity and mechanical strength.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrolytic copper foil production and preparation, and particularly relates to a multi-walled carbon nanotube additive for double-sided smooth high-strength ultra-thin electrolytic copper foil. BACKGROUND

[0002] As an important component of the lithium ion battery negative current collector, the performance of the electrolytic copper foil directly affects the performance of the lithium ion battery [1,2] . By reducing the thickness of the electrolytic copper foil, the weight of the lithium ion battery can be reduced, and the mass energy density can be improved, thereby reducing the consumption of copper, alleviating the resource crisis, and meeting the demand for green and low-carbon development [3,4] . For electrolytic copper foils with a thickness of less than 10 μm, the tensile strength and elongation are insufficient, and cracks are easily generated during the coating and assembly stages of battery manufacturing, making it difficult to meet the high performance requirements of lithium ion batteries.

[0003] The development of single / multi-walled carbon nanotube composites with uniform dispersion of carbon nanotubes (CNTs) has attracted widespread attention as excellent thermal and electrical conductors [5,6] . As a carbon nanomaterial, CNTs generally have excellent mechanical properties, electrical conductivity, and thermal conductivity [7] . When carbon nanotubes are used as additives for electrolytic copper foil, they can be uniformly distributed on the copper foil substrate, effectively inhibiting the generation and expansion of cracks on the copper foil surface, thereby enhancing the mechanical properties.

[0004] However, due to the low purity of carbon nanotubes themselves, the strong van der Waals interaction induces CNTs to aggregate, making CNTs prone to aggregation and stratification in electrolyte, with a small migration rate and low deposition efficiency. During the electrodeposition process, copper ions will preferentially nucleate and deposit on the surface of carbon nanotubes, easily causing uneven thickness of the copper foil, which seriously restricts the application of carbon nanotubes in the field of electrolytic copper foil.

[0005] REFERENCES

[0006] [1] Fan Binfeng, Wang Xujun, Wang Qingfu, et al. Effect of Additives on the Electrodeposition Process of Ultra-thin Lithium Battery Copper Foil [J]. Electroplating and Finishing, 2023, 45(05): 85-89.

[0007] [2] Zhang Xiaohong, Zhang Haijun, Zhang Jinlong. Lithium Battery Copper Foil Station on the "Hot Spot" [J]. China Nonferrous Metals, 2022, (03): 46-47.

[0008] [3] Fan Binfeng, Wang Lina, Wang Qingfu, et al. Study on New Additives for Improving High Temperature Elongation of Lithium Battery Copper Foil [J]. Electroplating and Finishing, 2024, 46(03): 108-113.

[0009] [4] ZHAO Z, HU H, SONG K, et al. Effects of PEG and MPS on structure and mechanical properties of electrolytic copper foil[J]. Electroplating and Coating, 2023, 42(21): 54-64.

[0010] [5] XU S, WANG Y, LI W, et al. Preparation, microstructure and properties of CNTs / Cu laminated composite[J]. Hot Working Technology, 2024, (14): 69-72.

[0011] [6] ZHANG H. Preparation of laminated high-strength and high-conductivity carbon nanotube / copper-based composite materials by composite electrodeposition[D]. Kunming University of Science and Technology, 2022.

[0012] [7] FU J, MAN T, WANG J, et al. Effect of CNTs / MXene on the conductivity of composite coating[J]. Chemical Reaction Engineering and Technology, 2023, 39(06): 519-524. SUMMARY

[0013] The purpose of the present application is to overcome at least one of the deficiencies of the prior art and provide a multi-walled carbon nanotube additive for double-sided smooth high-strength ultra-thin electrolytic copper foil.

[0014] The technical solution adopted by the present application is:

[0015] In a first aspect, the present application provides a multi-walled carbon nanotube additive for double-sided smooth high-strength ultra-thin electrolytic copper foil, the concentrations of the components of the additive in the copper sulfate solution are: multi-walled carbon nanotubes 0.22-0.48 g / L, hydrochloric acid 28-35 mg / L, polydithiopropane sulfonic acid sodium 2.6-5.2 mg / L, collagen 6-12 mg / L, polyethylene glycol 4.5-6.8 mg / L, and hydroxyethyl cellulose 3.5-4.8 mg / L.

[0016] The number of walls of the multi-walled carbon nanotubes is an integer between 3 and 9.

[0017] The length:diameter of the multi-walled carbon nanotubes is (110-125):(1-1.5).

[0018] In some examples, the mass ratio of polyethylene glycol to polydithiopropane sulfonic acid sodium in the additive is (1-1.5):(1-1.25).

[0019] In some examples, the length:diameter of the multi-walled carbon nanotubes is 118:1.

[0020] In some examples, the number of walls of the multi-walled carbon nanotubes is 6.

[0021] In some examples, the mass ratio of polyethylene glycol to polydithiopropane sulfonic acid sodium in the additive is 1.47:1.

[0022] In some examples, the concentrations of each component of the additive in the copper sulfate solution are: multi-walled carbon nanotubes 0.35 g / L, hydrochloric acid 32 mg / L, sodium polydithiopropane sulfonate 3.6 mg / L, collagen 9 mg / L, polyethylene glycol 5.3 mg / L, and hydroxyethyl cellulose 4.0 mg / L.

[0023] The above features can be combined arbitrarily without conflict.

[0024] In a second aspect, the present application provides a method for preparing a double-sided smooth high-strength ultra-thin electrolytic copper foil, comprising the following steps: adding the additive of the first aspect into a copper sulfate solution, and sequentially performing electrolytic foil formation, roughening treatment, solidification treatment, acid pickling, and silanization treatment to obtain the double-sided smooth high-strength ultra-thin electrolytic copper foil.

[0025] In some examples, the concentration of copper sulfate in the copper sulfate solution is 85-140 g / L.

[0026] In some examples, the current density of the electrolytic foil formation is 4.0-5.0 A / dm 2 .

[0027] In some examples, the anode for electrolysis is graphite, and the cathode is a pure titanium plate.

[0028] The above features can be combined arbitrarily without conflict.

[0029] The present application has the following beneficial effects:

[0030] The additive of the present application significantly improves the surface roughness of the prepared copper foil, the C element is uniformly distributed on the surface of the copper foil, and the electrical conductivity is effectively improved.

[0031] In some examples, the copper foil prepared by the present application has a roughness of the rough surface of less than 1.5 μm, the rough surface is uniform and spherical, the thickness of the copper foil is 6 μm, the tensile strength is greater than 480 MPa, the elongation is greater than 5%, and the electrical conductivity is greater than 62.3 MS / m. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is an SEM image of the electrolytic copper foil product obtained in Example 3.

[0033] Figure 2 is an AFM image of the rough surface roughness of the electrolytic copper foil product of Example 7.

[0034] Figure 3 is an SEM image of the electrolytic copper foil product of Comparative Example 2. DETAILED DESCRIPTION

[0035] The disclosure below provides many different embodiments or examples for implementing different aspects of the present application.

[0036] The process for each example of electrolytic copper foil in the present application is as follows:

[0037] The mixed multi-walled carbon nanotube copper sulfate electrolyte is added to the electrolytic cell, graphite is used as the anode plate, pure titanium is used as the cathode plate, direct current is used as the electrolysis power source, and a circulating pump is added to the electrolytic cell. In the following examples, the process of electrolytic green foil-roughening treatment-curing treatment-acid pickling-siliconization treatment is the same unless otherwise specified.

[0038] Example 1

[0039] Graphite is used as the anode plate, pure titanium is used as the cathode plate, direct current is applied, copper sulfate 90 g / L, multi-walled carbon nanotubes (4 walls, 114 nm long, 1 nm in diameter) 0.3 g / L, hydrochloric acid 29 mg / L, sodium polydithiopropane sulfonate 3.0 mg / L, collagen 7 mg / L, polyethylene glycol 5.2 mg / L, and hydroxyethyl cellulose 4.0 mg / L are added to the electrolyte, and the current density of the electrolytic green foil is 4.0 A / dm 2 The preparation process flow is electrolytic green foil-roughening treatment-curing treatment-acid pickling-siliconization treatment, and 6.0 μm double-sided light high-strength ultra-thin electrolytic copper foil is obtained.

[0040] Example 2

[0041] Graphite is used as the anode plate, pure titanium is used as the cathode plate, direct current is applied, copper sulfate 110 g / L, multi-walled carbon nanotubes (6 walls, 118 nm long, 1.1 nm in diameter) 0.32 g / L, hydrochloric acid 30 mg / L, sodium polydithiopropane sulfonate 3.0 mg / L, collagen 7 mg / L, polyethylene glycol 5.2 mg / L, and hydroxyethyl cellulose 4.0 mg / L are added to the electrolyte, and the current density of the electrolytic green foil is 4.2 A / dm 2 The preparation process flow is electrolytic green foil-roughening treatment-curing treatment-acid pickling-siliconization treatment, and 6.0 μm double-sided light high-strength ultra-thin electrolytic copper foil is obtained.

[0042] Example 3

[0043] Graphite is used as the anode plate, pure titanium is used as the cathode plate, direct current is applied, copper sulfate 110 g / L, multi-walled carbon nanotubes (6 walls, 118 nm long, 1.1 nm in diameter) 0.32 g / L, hydrochloric acid 30 mg / L, sodium polydithiopropane sulfonate 3.0 mg / L, collagen 7 mg / L, polyethylene glycol 5.2 mg / L, and hydroxyethyl cellulose 4.0 mg / L are added to the electrolyte, and the current density of the electrolytic green foil is 4.2 A / dm 2The preparation process includes electrolytic foil production, roughening treatment, solidification treatment, acid pickling and silanization treatment, and 6.0 μm double-sided light high-strength ultra-thin electrolytic copper foil is obtained.

[0044] Example 4

[0045] Graphite is used as an anode plate, pure titanium is used as a cathode plate, a direct current power supply is connected, 110 g / L of copper sulfate, 0.32 g / L of multi-walled carbon nanotubes (6 walls, 118 nm long, 1.1 nm in diameter), 30 mg / L of hydrochloric acid, 3.0 mg / L of polydithiopropane sulfonic acid sodium, 7 mg / L of collagen, 6.5 mg / L of polyethylene glycol, and 4.0 mg / L of hydroxyethyl cellulose are added to an electrolyte, and the current density of electrolytic foil production is 4.2 A / dm 2 The preparation process includes electrolytic foil production, roughening treatment, solidification treatment, acid pickling and silanization treatment, and 6.0 μm double-sided light high-strength ultra-thin electrolytic copper foil is obtained.

[0046] Example 5

[0047] Graphite is used as an anode plate, pure titanium is used as a cathode plate, a direct current power supply is connected, 125 g / L of copper sulfate, 0.48 g / L of multi-walled carbon nanotubes (9 walls, 115 nm long, 1.5 nm in diameter), 32 mg / L of hydrochloric acid, 3.6 mg / L of polydithiopropane sulfonic acid sodium, 9 mg / L of collagen, 5.3 mg / L of polyethylene glycol, and 4.0 mg / L of hydroxyethyl cellulose are added to an electrolyte, and the current density of electrolytic foil production is 4.2 A / dm 2 The preparation process includes electrolytic foil production, roughening treatment, solidification treatment, acid pickling and silanization treatment, and 6.0 μm double-sided light high-strength ultra-thin electrolytic copper foil is obtained.

[0048] Example 6

[0049] Graphite is used as an anode plate, pure titanium is used as a cathode plate, a direct current power supply is connected, 125 g / L of copper sulfate, 0.48 g / L of multi-walled carbon nanotubes (9 walls, 115 nm long, 1.5 nm in diameter), 32 mg / L of hydrochloric acid, 3.6 mg / L of polydithiopropane sulfonic acid sodium, 9 mg / L of collagen, 5.3 mg / L of polyethylene glycol, and 4.0 mg / L of hydroxyethyl cellulose are added to an electrolyte, and the current density of electrolytic foil production is 4.2 A / dm 2 The preparation process includes electrolytic foil production, roughening treatment, solidification treatment, acid pickling and silanization treatment, and 6.0 μm double-sided light high-strength ultra-thin electrolytic copper foil is obtained.

[0050] Example 7

[0051] Graphite is used as anode plate, pure titanium is used as cathode plate, direct current power is input, copper sulfate 125 g / L, multi-walled carbon nanotube (wall number 6, length 118 nm, diameter 1 nm) 0.22-0.48 g / L, hydrochloric acid 28-35 mg / L, polydithiopropane sulfonic acid sodium 2.6-5.2 mg / L, collagen 6-12 mg / L, polyethylene glycol 4.5-6.8 mg / L, hydroxyethyl cellulose 3.5-4.8 mg / L are added into electrolyte, and the current density of electrolytic foil is 4.2 A / dm 2 The preparation process is through electrolytic foil-roughening treatment-curing treatment-acid pickling-silanization treatment, and 6.0 μm double-sided light high-strength ultra-thin electrolytic copper foil is obtained.

[0052] Example 8

[0053] Graphite is used as anode plate, pure titanium is used as cathode plate, direct current power is input, copper sulfate 125 g / L, multi-walled carbon nanotube (wall number 6, length 118 nm, diameter 1 nm) 0.22-0.48 g / L, hydrochloric acid 28-35 mg / L, polydithiopropane sulfonic acid sodium 2.6-5.2 mg / L, collagen 6-12 mg / L, polyethylene glycol 4.5-6.8 mg / L, hydroxyethyl cellulose 3.5-4.8 mg / L are added into electrolyte, and the current density of electrolytic foil is 4.2 A / dm 2 The preparation process is through electrolytic foil-roughening treatment-curing treatment-acid pickling-silanization treatment, and 6.0 μm double-sided light high-strength ultra-thin electrolytic copper foil is obtained.

[0054] Example 9

[0055] Graphite is used as anode plate, pure titanium is used as cathode plate, direct current power is input, copper sulfate 125 g / L, multi-walled carbon nanotube (wall number 6, length 118 nm, diameter 1 nm) 0.22-0.48 g / L, hydrochloric acid 28-35 mg / L, polydithiopropane sulfonic acid sodium 2.6-5.2 mg / L, collagen 6-12 mg / L, polyethylene glycol 4.5-6.8 mg / L, hydroxyethyl cellulose 3.5-4.8 mg / L are added into electrolyte, and the current density of electrolytic foil is 4.2 A / dm 2 The preparation process is through electrolytic foil-roughening treatment-curing treatment-acid pickling-silanization treatment, and 6.0 μm double-sided light high-strength ultra-thin electrolytic copper foil is obtained.

[0056] Example 10

[0057] Graphite is used as anode plate, pure titanium is used as cathode plate, direct current power is input, copper sulfate 125 g / L, multi-walled carbon nanotube (wall number 6, length 118 nm, diameter 1 nm) 0.22-0.48 g / L, hydrochloric acid 28-35 mg / L, polydithiopropane sulfonic acid sodium 2.6-5.2 mg / L, collagen 6-12 mg / L, polyethylene glycol 4.5-6.8 mg / L, hydroxyethyl cellulose 3.5-4.8 mg / L are added into electrolyte, and the current density of electrolytic foil is 4.2 A / dm2 The preparation process includes electrolytic foil production, roughening treatment, solidification treatment, acid pickling and silanization treatment, and 6.0 μm double-sided light high-strength ultra-thin electrolytic copper foil is obtained.

[0058] Comparative Example 1

[0059] Graphite was used as the anode plate, pure titanium was used as the cathode plate, a direct current power supply was passed, copper sulfate 140 g / L, multi-walled carbon nanotubes (9 walls, 115 nm long, 1.5 nm in diameter) 0.48 g / L, hydrochloric acid 30 mg / L, polydithiopropane sulfonic acid sodium 3.6 mg / L, collagen 12 mg / L, polyethylene glycol 5.5 mg / L, hydroxyethyl cellulose 4.0 mg / L were added to the electrolyte, and the current density of the electrolytic foil was 15.0 A / dm 2 The preparation process includes electrolytic foil production, roughening treatment, solidification treatment, acid pickling and silanization treatment, and 6.0 μm double-sided light high-strength ultra-thin electrolytic copper foil is obtained.

[0060] Comparative Example 2

[0061] Graphite was used as the anode plate, pure titanium was used as the cathode plate, a direct current power supply was passed, copper sulfate 140 g / L, multi-walled carbon nanotubes (15 walls, 135 nm long, 7.5 nm in diameter) 1.5 g / L, hydrochloric acid 30 mg / L, polydithiopropane sulfonic acid sodium 3.6 mg / L, collagen 12 mg / L, polyethylene glycol 5.5 mg / L, hydroxyethyl cellulose 4.0 mg / L were added to the electrolyte, and the current density of the electrolytic foil was 5.0 A / dm 2 The preparation process includes electrolytic foil production, roughening treatment, solidification treatment, acid pickling and silanization treatment, and 6.0 μm double-sided light high-strength ultra-thin electrolytic copper foil is obtained.

[0062] Comparative Example 3

[0063] Graphite was used as the anode plate, pure titanium was used as the cathode plate, a direct current power supply was passed, copper sulfate 140 g / L, multi-walled carbon nanotubes (9 walls, 115 nm long, 1.5 nm in diameter) 0.48 g / L, hydrochloric acid 30 mg / L, polydithiopropane sulfonic acid sodium 3.6 mg / L, collagen 12 mg / L, polyethylene glycol 10.5 mg / L, hydroxyethyl cellulose 4.0 mg / L were added to the electrolyte, and the current density of the electrolytic foil was 5.0 A / dm 2 The preparation process includes electrolytic foil production, roughening treatment, solidification treatment, acid pickling and silanization treatment, and 6.0 μm double-sided light high-strength ultra-thin electrolytic copper foil is obtained.

[0064] Comparative Example 4

[0065] Graphite as anode plate, pure titanium as cathode plate, direct current power supply is passed, copper sulfate 140g / L, multi-walled carbon nanotubes (wall number 9, length 115nm, diameter 1.5nm) 0.48g / L, hydrochloric acid 30mg / L, polydithiopropane sulfonic acid sodium 3.6mg / L, collagen 12mg / L, polyethylene glycol 5.5mg / L, hydroxyethyl cellulose 4.0mg / L are added into electrolyte, and the current density of electrolytic foil is 5.0 A / dm 2 The preparation process is through electrolytic foil - solidification treatment - pickling - silanization treatment, and 6.0μm double-sided light high-strength ultra-thin electrolytic copper foil is obtained.

[0066] Comparative example 5

[0067] Graphite as anode plate, pure titanium as cathode plate, direct current power supply is passed, copper sulfate 180g / L, multi-walled carbon nanotubes (wall number 9, length 115nm, diameter 1.5nm) 0.48g / L, hydrochloric acid 30mg / L, polydithiopropane sulfonic acid sodium 3.6mg / L, collagen 12mg / L, polyethylene glycol 5.5mg / L, hydroxyethyl cellulose 4.0mg / L are added into electrolyte, and the current density of electrolytic foil is 5.0 A / dm 2 The preparation process is through electrolytic foil - roughening treatment - solidification treatment - pickling - silanization treatment, and 6.0μm double-sided light high-strength ultra-thin electrolytic copper foil is obtained.

[0068] Performance detection

[0069] According to the national standard GB / T15970.7-2000 tensile test, the prepared electrolytic copper foil material is detected, and the conductivity, tensile strength and elongation of the 6.0μm double-sided light high-strength ultra-thin electrolytic copper foil material in the above embodiment are shown in Table 1.

[0070] Table 1, performance test results of different electrolytic copper foils

[0071] No. Tensile strength (MPa) Ra roughness (pm) Electrical conductivity (MS / m) Elongation (%) Example 1 482 1.5 62.4 5.1 Example 2 493 1.4 62.8 5.0 Example 3 490 1.4 62.3 5.1 Example 4 502 1.3 62.7 5.2 Example 5 509 1.4 62.8 5.4 Example 6 508 1.3 63.0 5.3 Example 7 512 1.2 63.2 5.4 Example 8 506 1.3 63.2 5.0 Example 9 502 1.4 62.9 5.1 Example 10 504 1.2 63.0 5.1 Comparative Example 1 475 3.0 61.9 4.3 Comparative Example 2 477 2.6 60.8 4.6 Comparative Example 3 465 2.8 61.2 4.3 Comparative Example 4 467 2.1 62.0 4.7 Comparative Example 5 479 1.9 60.8 4.6

[0072] From the data in Table 1, it can be seen that:

[0073] 1) In the embodiment 7 of the application, copper sulfate 125g / L, multi-walled carbon nanotubes (wall number 9, length 115nm, diameter 1.5nm) 0.48g / L, hydrochloric acid 32mg / L, polydithiopropane sulfonic acid sodium 3.6mg / L, collagen 9mg / L, polyethylene glycol 5.3mg / L, hydroxyethyl cellulose 4.0mg / L have the best performance in each example.

[0074] 2) In comparative examples 2, 3 and 5, the multi-walled carbon nanotubes, polyethylene glycol and copper sulfate exceed the limited range, resulting in the decrease of tensile strength, elongation, conductivity and surface roughness.

[0075] Figure 1 is an SEM image of the finished electrolytic copper foil product obtained in Example 3. It can be seen from Figure 1 that, with suitable electrolyte additives, the surface grain distribution of the copper foil is uniform, without obvious void defects, and is relatively smooth and flat.

[0076] Figure 2 is an AFM image of the rough surface of the finished electrolytic copper foil product of Example 7. It can be seen from Figure 2 that the surface roughness of the local rough surface of the electrolytic copper foil is within 1 μm, the surface is smooth, and the electrical conductivity of the copper foil can be significantly improved.

[0077] Figure 3 is an SEM image of the finished electrolytic copper foil product of Comparative Example 2. It can be seen from Figure 3 that the aspect ratio, number, and concentration of the multi-walled carbon nanotubes exceed the limited range, resulting in local void defects on the surface of the copper foil, and significantly reducing the mechanical properties and electrical conductivity.

[0078] The above is a further detailed description of the present application, which cannot be considered as a limitation on the specific implementation of the present application. For those of ordinary skill in the art to which the present application belongs, simple deductions or substitutions without departing from the concept of the present application are within the protection scope of the present application.

Claims

1. A multi-walled carbon nanotube additive for double-sided smooth high-strength ultra-thin electrolytic copper foil, characterized by, The concentration of each component of the additive in the copper sulfate solution is: multi-walled carbon nanotubes 0.22-0.48 g / L, hydrochloric acid 28-35 mg / L, sodium polydithiopropane sulfonate 2.6-5.2 mg / L, collagen 6-12 mg / L, polyethylene glycol 4.5-6.8 mg / L, and hydroxyethyl cellulose 3.5-4.8 mg / L. The multi-walled carbon nanotubes have an integer number of 3-9 walls. The length:diameter of the multi-walled carbon nanotubes is (110-125):(1-1.5).

2. The additive of claim 1, wherein The mass ratio of polyethylene glycol to sodium polydithiopropane sulfonate in the additive is (1-1.5):(1-1.25).

3. The additive of claim 1, wherein The length:diameter of the multi-walled carbon nanotubes is 118:

1.

4. The additive of claim 1, wherein The multi-walled carbon nanotubes have 6 walls.

5. The additive according to any one of claims 1 to 4, characterized in that, The mass ratio of polyethylene glycol to sodium polydithiopropane sulfonate in the additive is 1.47:

1.

6. The additive of claim 1, wherein, The concentration of each component of the additive in the copper sulfate solution is: multi-walled carbon nanotubes 0.35 g / L, hydrochloric acid 32 mg / L, sodium polydithiopropane sulfonate 3.6 mg / L, collagen 9 mg / L, polyethylene glycol 5.3 mg / L, and hydroxyethyl cellulose 4.0 mg / L.

7. A method for preparing a double-sided smooth high-strength ultra-thin electrolytic copper foil, characterized in that The method comprises the following steps: adding the additive of any one of claims 1-6 into a copper sulfate solution, mixing, sequentially performing electrolytic foil production, roughening treatment, solidification treatment, acid pickling, and silanization treatment to obtain the double-sided smooth high-strength ultra-thin electrolytic copper foil.

8. The preparation method according to claim 7, characterized in that, The concentration of copper sulfate in the copper sulfate solution is 85-140 g / L.

9. The preparation method according to claim 7, characterized in that, The current density of the electrolytic foil is 4.0-5.0 A / dm 2 .

10. The method of claim 7, wherein, The anode for electrolysis is graphite, and the cathode is a pure titanium plate. The anode for electrolysis is graphite, and the cathode is a pure titanium plate.

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