Additive applied to electrolytic copper foil production

Abstract

The invention discloses an additive applied to electrolytic copper foil production. The additive comprises the following components in an electrolyte: 20-40ppm of a hydroxyethyl cellulose mixture; the hydroxyethyl cellulose mixture is formed by mixing hydroxyethyl cellulose with different viscosities. According to the method, hydroxyethyl cellulose is creatively matched with different viscosities, the technical prejudice that hydroxyethyl cellulose with single physicochemical property is adopted for treatment in the conventional technology is overcome, the compactness of the copper foil obtained through corresponding electrolysis is remarkably improved, and then the tensile strength, the ductility and other mechanical properties of the copper foil are improved; therefore, the mechanical performance is further improved. The invention creatively provides a new additive regulation and control direction, which is beneficial to promoting the performance development of the ultrathin copper foil on the basis of the new additive regulation and control direction. When the copper foil is applied to an ultrathin material, such as a composite current collector, sufficient physical properties and support can be provided, and the performance characteristics required by the corresponding composite current collector are guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic copper foil production, and more specifically, to an additive applied to the production of electrolytic copper foil. Background Art

[0002] Electrolytic copper foil is a copper foil produced by electrolysis and is an important material for manufacturing products such as batteries. At the same time, in order to improve various properties of electrolytic copper foil (such as thickness, roughness, tensile strength, elongation, etc.), corresponding additives are usually added during electrolysis in the prior art, and the additives have an important impact on the properties of electrolytic copper foil products.

[0003] The additive regulates the properties of the copper foil by changing the microstructure of the coating. However, although there are various additive formulations proposed in the prior art, such as using brighteners, leveling agents, etc. But in specific use, the usage mode of the additive formulation components is usually relatively single, and the improvement of the tensile strength or elongation of the copper foil is relatively limited, and it is difficult to achieve further performance improvement, etc.

[0004] Therefore, there is an urgent need for a new additive to further improve the mechanical properties of electrolytic copper foil in a new regulation direction and also facilitate the improvement of the overall performance in combination with other components. Summary of the Invention

[0005] The present invention aims to overcome at least one of the above-mentioned deficiencies in the prior art and provides an additive applied to the production of electrolytic copper foil, which is convenient for improving the mechanical properties of electrolytic copper foil.

[0006] The technical solution adopted by the present invention is an additive applied to the production of electrolytic copper foil, and the components of the additive in the electrolyte include: Hydroxyethyl cellulose mixture 20 - 40 ppm; The hydroxyethyl cellulose mixture is formed by mixing hydroxyethyl celluloses with different viscosities.

[0007] The viscosity is the viscosity b, with the unit of mPa·s; the corresponding viscosity is that of a 2% aqueous solution of the corresponding hydroxyethyl cellulose, measured by a Brook viscometer at 25 °C. And the molecular weight of hydroxyethyl cellulose is positively correlated with the viscosity, that is, the hydroxyethyl cellulose mixture can also be considered to be formed by mixing hydroxyethyl celluloses with different molecular weights. The present inventors found that in the specific production process, when adding a hydroxyethyl cellulose mixture with different viscosities to an electrolyte containing copper ions, the compactness and breaking strength of the electrolytically produced copper foil are significantly enhanced. It is speculated that this may be because the hydroxyethyl cellulose mixture contains hydroxyethyl celluloses with different molecular weights. As the hydroxyethyl cellulose binds to copper ions, the hydroxyethyl celluloses with different molecular weights achieve the binding between copper ions in different directions and at different distances. Through the hydroxycelluloses with different molecular weights, a more complex copper ion distribution network can be formed by bridging and bonding, forming a complex structure with a wide distribution and dense copper ions. Thereby significantly improving the compactness of the electrolytically obtained copper foil, reducing pinholes, lowering the light transmittance, etc., and significantly enhancing the breaking strength. At the same time, the mechanical properties such as elongation are also significantly improved. The additive of the present application utilizes the cooperation of different molecular weights of hydroxyethyl cellulose to overcome the improvement bottleneck of the additives in the prior art. Further, the proportion of the different viscosity hydroxyethyl celluloses in the hydroxyethyl cellulose mixture can be adjusted according to requirements. The component content of the additive in the electrolyte at least includes the concentration presented in the overall electrolytic solution after the additive is added to the electrolyte.

[0008] Further, the hydroxyethyl cellulose mixture at least includes different viscosity hydroxyethyl celluloses with a viscosity difference of more than 1000 mPa·s. Even further, the hydroxyethyl cellulose mixture at least includes different viscosity hydroxyethyl celluloses with a viscosity difference of more than 3000 mPa·s. When there is a certain degree of viscosity / molecular weight difference between different hydroxyethyl celluloses, it is convenient to cross-bind copper ions in a wider distance range, forming a complex and wide cross-network, further improving the compactness and stability of the corresponding obtained foil.

[0009] Further, the hydroxyethyl cellulose mixture is formed by mixing at least two different viscosity hydroxyethyl celluloses within the viscosity range of 15000 - 100000 mPa·s. Further, the hydroxyethyl cellulose mixture can be formed by mixing two or more of the hydroxyethyl celluloses with viscosities of 20000 mPa·s, 24000 mPa·s, 30000 mPa·s, and 90000 mPa·s. In more than one embodiment of the present invention, through the combination and mixing of the above several viscosity hydroxyethyl celluloses, the mechanical properties of the copper foil are significantly improved during the production process of electrolytic copper foil.

[0010] Further, the copper foil is an ultra-thin copper foil with a thickness of 1.5 to 15 μm. The additive of the present application can achieve the treatment of ultra-thin copper foil, so as to have strong mechanical properties on the premise of ensuring its ultra-thinness; thus, it is suitable for specific downstream products, especially for a type of ultra-thin materials with requirements for mechanical properties, such as composite current collectors, etc.

[0011] Further, the components of the additive in the electrolyte also include: Brightener: 5 to 20 ppm; And / or, wetting agent: 5 to 20 ppm; The brightener includes one or more of the group consisting of sulfur-containing organic brighteners, 4-phenylimidazole, 2-benzylimidazoline, hexylbenzylamine salt, or diphenylvinylpyridine. The sulfur-containing organic brighteners include one or more of the group consisting of sodium polydithiopropanesulfonate, sodium thiazolinyl dithiopropanesulfonate, sodium trimethylformamide sulfonate, N,N-dimethyldithiocarboxamide propane sulfonate, 3-mercapto-1-propane sulfonate, sodium diphenylamine sulfonate, L-dithiothreitol, 3-(benzothiazole-2-mercapto) propane sulfonate, 2-hydroxy-3-mercapto sodium sulfonate, tetrahydrothiazolethione, phenyl polydithiopropane sulfonate, alcohol mercapto propane sulfonate, sodium ethyl dithiocarbonate propyl sulfonate, thiourea, polyisothiourea propanesulfonic acid inner salt, or 2-hydroxy phenylthiourea.

[0012] The wetting agent includes one or more of the group consisting of polyethylene glycol (PEG), octylphenol polyethylene glycol ether (OP), or polypropylene glycol (PPG).

[0013] Based on the brightener and the wetting agent, the brightener can at least be used to regulate the brightness of the copper foil surface, inhibit the generation of impurities, and ensure the weather resistance of the coating; the wetting agent is beneficial to better covering the surface of the workpiece with the electroplating liquid, reducing the production of bubbles, and promoting the uniform distribution of the electroplating solution, thereby improving the uniformity and quality of the coating.

[0014] Further, the brightener is sodium polydithiopropanesulfonate, and the wetting agent is polyethylene glycol. In one or more embodiments of the present invention, using sodium polydithiopropanesulfonate as the brightener and polyethylene glycol as the wetting agent can promote the process of electrolytic production of copper foil.

[0015] Further, the components of the additive in the electrolyte solution further include a leveling agent, and the leveling agent includes one or more selected from the group consisting of nitrogen-containing organic leveling agents or agarose; the nitrogen-containing organic compound leveling agent includes one or more selected from the group consisting of diaminopolyethylene glycol or amine-based organic compounds; the amine-based organic compounds include one or more selected from the group consisting of Janus green, polyethyleneimine compounds, 1,1-dimethylpropyneamine, alkylated polyethyleneimine, quaternary ammonium salts, benzotriazole or arginine; further, the polyethyleneimine compounds include one or more selected from the group consisting of polyethyleneimine, polyethyleneimine alkyl compounds, N-acetyl ethyleneimine, polyethyleneimine alkane or ethoxy polyethyleneimine. The component content range of the leveling agent in the electrolyte solution is 0.01-20 ppm.

[0016] An electrolytic solution for preparing a copper foil (i.e., an electrolyte solution for generating an electrolytic copper foil), comprising: An electrolyte mother liquor, and the aforementioned additive; The electrolyte mother liquor includes: Cu 2+ 65-90 g / L; H2SO4 75-100 g / L; Cl - 20-30 ppm.

[0017] Through the electrolytic solution containing the aforementioned additive, as the electrolysis process proceeds, an electrolytic copper foil with improved mechanical properties in all aspects can be formed. And the overall system is relatively stable, which can effectively exert the effects of the electrolyte mother liquor and the additive. It is also convenient to further improve the electrolytic solution based on this.

[0018] Another object of the present invention is to provide an electrolytic copper foil production process, including the steps of: A1. Prepare the aforementioned electrolytic solution and supply the electrolytic solution between the anode structure and the cathode structure; A2. Circulate the electrolytic solution at 45-55 °C and an anode structure current density of 40-70 A / dm² for electrolytic copper foil production to obtain the corresponding electrolytic copper foil.

[0019] That is, a production process adapted to the aforementioned electrolytic solution, within this temperature range and current density, to obtain a correspondingly enhanced electrolytic copper foil. Further, the anode structure can be an anode plate, and the cathode structure can be a cathode plate or a cathode roll. The electrolytic copper foil production process can be a continuous plating process.

[0020] Further, in step A1, first prepare the electrolytic mother liquor, and then add the additive to the electrolytic mother liquor. After the components reach the expected concentration, the corresponding electrolytic solution is formed; the electrolytic mother liquor is the aforementioned electrolytic mother liquor.

[0021] Another object of the present invention is to provide a copper foil prepared by electroplating with the aforementioned electroplating solution or obtained by the aforementioned electrolytic copper foil production process. Further, the application of the copper foil in the preparation of a composite current collector is provided.

[0022] Another object of the present invention is to provide the application of a hydroxyethyl cellulose mixture in the preparation of a copper foil production additive or an electrolytic solution, wherein the hydroxyethyl cellulose mixture is formed by mixing hydroxyethyl celluloses with different viscosities. Further, the hydroxyethyl cellulose mixture is formed by mixing hydroxyethyl celluloses within the viscosity range of 15,000 to 100,000 mPa·s. Further, the copper foil production additive is an electrolytic copper foil production additive.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: Creatively, hydroxyethyl celluloses with different viscosities / molecular weights are combined, and hydroxyethyl celluloses with different physical and chemical properties (such as molecular weight) act synergistically to overcome the technical prejudice of using hydroxyethyl cellulose with a single physical and chemical property (such as molecular weight) in the conventional technology, significantly improving the compactness of the copper foil obtained by electrolysis, and further improving its mechanical properties such as tensile strength and elongation; so as to achieve further improvement in mechanical properties. Moreover, the present application creatively proposes a new direction for additive regulation, which is conducive to promoting the performance development of ultra-thin copper foils based on this. And when the hydroxyethyl cellulose mixture is combined with other components to form the final electrolytic solution, the properties of the copper foil obtained by electrolysis can be improved in many aspects, including flatness, tensile strength, elongation, compactness, and surface brightness. When such a copper foil is applied to ultra-thin materials, such as composite current collectors, it can provide sufficient physical properties and support to ensure the performance characteristics required by the corresponding composite current collectors. Detailed Embodiments

[0024] The technical solutions of the present invention will be clearly and completely described below in conjunction with the specific embodiments. However, those skilled in the art will understand that the following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention. Those not specified in the embodiments are carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments not specified by the manufacturer are all conventional products that can be obtained through commercial purchase. Example 1

[0025] This embodiment discloses an additive applied to the production of electrolytic copper foil. The components of the additive in the electrolyte include: 20-40 ppm of hydroxyethyl cellulose mixture; the hydroxyethyl cellulose mixture is formed by mixing hydroxyethyl celluloses with different viscosities. The component content of the additive in the electrolyte at least includes the concentration presented in the overall electrolytic solution after the additive is added to the electrolyte. The proportion of different viscosity hydroxyethyl celluloses in the hydroxyethyl cellulose mixture can be adjusted according to requirements. In this embodiment, the hydroxyethyl cellulose mixture at least includes hydroxyethyl celluloses with viscosities differing by more than 1000 mPa.s.

[0026] The hydroxyethyl cellulose mixture is formed by mixing hydroxyethyl celluloses with different viscosities in the viscosity range of 15000-100000 mPa.s. Specifically, the hydroxyethyl cellulose mixture is formed by mixing two or more of hydroxyethyl celluloses with viscosities of 20000 mPa.s, 24000 mPa.s, 30000 mPa.s, and 90000 mPa.s. It should be noted that the specific values listed are examples of the main viscosities of hydroxyethyl cellulose. Specifically, when achieving similar effects, an error of ±2000 mPa.s is allowed for the corresponding required viscosity of hydroxyethyl cellulose.

[0027] The target product of this application is an ultra-thin copper foil with a thickness of 1.5-15 μm. The additive of this application is mainly used in the process of electrolytic production of ultra-thin copper foil.

[0028] In the process of cooperating with the production of electrolytic copper foil, the components of the additive in the electrolyte may further include: Brightening agent 5-20 ppm; And / or, wetting agent 5-20 ppm; The brightening agent includes: one or more of sulfur-containing organic brightening agents, 4-phenylimidazole, 2-benzylimidazoline, hexylbenzylamine salt, or diphenylvinylpyridine. The sulfur-containing organic brightening agents include: one or more of sodium polydithiopropane sulfonate (SPS), sodium thiazolinyl dithiopropane sulfonate, sodium trimethylformamide sulfonate, sodium N,N-dimethyldithiocarboxamide propane sulfonate, 3-mercapto-1-propane sulfonate, sodium diphenylamine sulfonate, L-dithiothreitol, 3-(benzothiazole-2-mercapto)propane sulfonate, 2-hydroxy-3-mercapto sodium sulfonate, tetrahydrothiazolethione, phenyl polydithiopropane sulfonate, alcohol thiopropane sulfonate, sodium ethyl dithiocarbonate propyl sulfonate, thiourea, polyisothiourea propanesulfonic acid inner salt, or 2-hydroxy phenylthiourea.

[0029] The wetting agent includes: polyethylene glycol (PEG), octylphenol polyoxyethylene ether (OP), polypropylene glycol (PPG), etc.

[0030] In this embodiment, a brightening agent and a wetting agent can be included simultaneously. The brightening agent is sodium polydithiopropane sulfonate, and the wetting agent is polyethylene glycol. In addition, the components of the additive in the electrolyte solution can further include a leveling agent at 0.01 - 20 ppm. The leveling agent includes one or more of the group consisting of nitrogen-containing organic leveling agents or agarose; the nitrogen-containing organic compound leveling agent includes one or more of the group consisting of diaminopolyethylene glycol or amine-based organic compounds; the amine-based organic compounds include one or more of the group consisting of Janus green, polyethyleneimine compounds, 1,1-dimethylpropargylamine, alkylated polyethyleneimine, quaternary ammonium salts, benzotriazole, or arginine. Further, the polyethyleneimine compounds include one or more of the group consisting of polyethyleneimine, polyethyleneimine alkyl compounds, N-acetyl ethyleneimine, polyethyleneimine alkane, or ethoxylated polyethyleneimine. Example 2

[0031] This embodiment discloses an electrolytic solution for preparing copper foil. Based on the additive in the previous embodiment, it specifically includes: The electrolyte mother liquor and the additive in the previous Embodiment 1; The electrolyte mother liquor includes: Cu 2+ 65 - 90 g / L; H2SO4 75 - 100 g / L; Cl - 20 - 30 ppm.

[0032] Through the electrolytic solution containing the aforementioned additive, with the progress of the electrolysis process, an electrolytic copper foil with improved mechanical properties in all aspects can be formed. And the overall system is relatively stable, and can effectively exert the effects of the electrolyte mother liquor and the additive. Example 3

[0033] This embodiment discloses an electrolytic copper foil production process, including the steps: A1. Prepare the aforementioned electrolytic solution and supply the electrolytic solution between the anode structure and the cathode structure; A2. Circulate the electrolytic solution at 45 - 55 °C and an anode structure current density of 40 - 70 A / dm² for electrolytic copper foil production to obtain the corresponding electrolytic copper foil. Among them, in step A1, first prepare the electrolytic mother liquor, and then add the additive to the electrolytic mother liquor. After the components reach the expected concentration, the corresponding electrolytic solution is formed; the electrolytic mother liquor is the aforementioned electrolytic mother liquor.

[0034] That is, a production process adapted to the electrolytic solution of the foregoing Example 2. In this temperature range and current density, electrolytic copper foils that can correspondingly reflect the efficiency increase of the electrolytic solution can be obtained. The anode structure can be an anode plate, and the cathode structure can be a cathode plate or a cathode roll. The electrolytic copper foil production process can be a continuous plating process. Example 4

[0035] Based on Example 1 and Example 2, this example constructs multiple electrolytic solutions as described in the following table. Taking an experimental electrolytic cell as an example, a corresponding circulating electrolytic solution is formed, and electroplated copper foils are produced using this electrolytic solution. During the production process, the temperature is 45 - 55 °C, and the current density is 40 - 70 A / dm² to produce ultra-thin copper foils with a thickness specification of 4.5 μm.

[0036] In this example, the (viscosity of the first hydroxyethyl cellulose, viscosity of the second hydroxyethyl cellulose) represents the hydroxyethyl cellulose mixture formed by mixing the corresponding two hydroxyethyl celluloses, with the unit of mPa·s. In the mixing ratio, the first hydroxyethyl cellulose : the second hydroxyethyl cellulose is 1:1.

[0037] Test Group 1 Test Group 2 Test Group 3 Test Group 4 Test Group 5 Test Group 6 Test Group 7 Test Group 8 Hydroxyethyl Cellulose (Single Viscosity) / / / 25 ppm (20000) 30 ppm (30000) 40 ppm (24000) Hydroxyethyl Cellulose Mixture 20 ppm (20000,24000) 28 ppm (24000,30000) 39 ppm (24000,30000) 28 ppm (20000,24000) 28 ppm (24000,90000) / / / SPS 12 ppm 12 ppm 12 ppm 12 ppm 12 ppm 12 ppm 12 ppm 12 ppm PEG 12 ppm 12 ppm 12 ppm 12 ppm 12 ppm 12 ppm 12 ppm 12 ppm <![CDATA[Cu 2+ > 78 g / L 78 g / L 78 g / L 78 g / L 78 g / L 78 g / L 78 g / L 78 g / L <![CDATA[H2SO4]]> 85 g / L 85 g / L 85 g / L 85 g / L 85 g / L 85 g / L 85 g / L 85 g / L <![CDATA[Cl - > 25 ppm 25 ppm 25 ppm 25 ppm 25 ppm 25 ppm 25 ppm 25 ppm

[0038] Then, performance tests are conducted on the obtained electrolytic copper foils, and the performance test results of each group are as follows.

[0039] Pinholes (pieces / m²) Breaking Strength (Mpa) Elongation at Break (%) Glossiness (GU) Test Group 1 0 409.1 4.19 523 Test Group 2 0 422.5 4.38 519 Test Group 3 0 410.52 4.2 525 Test Group 4 0 417.35 4.25 528 Test Group 5 0 426.82 4.46 521 Test Group 6 0 372.13 3.55 529 Test Group 7 1 375.33 3.67 516 Test Group 8 0 377.26 3.76 517

[0040] The test results show that compared with the conventional hydroxyethyl cellulose with a single viscosity / molecular weight, the hydroxyethyl cellulose mixture formed by mixing different viscosities / molecular weights of hydroxyethyl cellulose in this application can significantly enhance the compactness, and is manifested as a significant increase in the tensile strength (breaking strength), and there is also an improvement in the elongation rate. In addition, the molecular weight mixing viscosity and mixing ratio in this example are only examples. When the inventor uses other different viscosity mixtures of hydroxyethyl cellulose and different ratios, the above similar conclusions are also shown. Example 5

[0041] In order to further verify the influence of the additive addition content and other components of the formula on the electrolytic copper foil, this example conducts further tests and constructs an electrolytic solution with the formula shown in the following table.

[0042] Test Group 9 Test Group 10 Test Group 11 Test Group 12 Test Group 13 Test Group 14 Test Group 15 Hydroxyethyl Cellulose Mixture 28 ppm (24000,30000) 0 ppm (24000,30000) 60 ppm (24000,30000) 28 ppm (24000,30000) 28 ppm (24000,30000) 20 ppm (24000,30000) 40 ppm (24000,30000) (SPS) 15 ppm 15 ppm 15 ppm 12 ppm 12 ppm 1 ppm 25 ppm (PEG) 15 ppm 15 ppm 15 ppm 0 ppm 12 ppm 15 ppm 16 ppm <![CDATA[Cu 2+ > 75 g / L 75 g / L 75 g / L 45 g / L 95 g / L 66 g / L 90 g / L <![CDATA[H2SO4]]> 85 g / L 85 g / L 85 g / L 70 g / L 120 g / L 75 g / L 98 g / L <![CDATA[Cl - > 25 ppm 25 ppm 25 ppm 15 ppm 35 ppm 22 ppm 30 ppm

[0043] Then, performance tests are conducted on the obtained electrolytic copper foils, and the performance test results of each group are as follows.

[0044] Pinholes (pieces / m²) Breaking Strength (Mpa) Elongation at Break (%) Glossiness (GU) Electrolyte Solution Stability Test Group 9 0 425.33 4.27 517 Yes Test Group 10 2 371.42 3.52 512 Yes Test Group 11 0 405.27 4.19 526 Yes Test Group 12 1 401.2 4.04 521 No Test Group 13 0 402.79 4.11 519 Yes Test Group 14 0 405.3 4.10 450 Yes Test Group 15 0 411.77 4.16 538 Yes

[0045] The test results show that, based on the electroplating solution formulation provided in this application, it not only has stable properties, but also can fully cooperate with other components to exert the functions of the hydroxyethyl cellulose mixture, enabling the corresponding electroplated copper foil to be improved in multiple mechanical properties. Example 6

[0046] This example discloses a copper foil, which is prepared by electroplating with the electrolytic solution of the previous example or obtained by the electrolytic copper foil production process of the previous example. This copper foil can be applied in the preparation process of composite current collectors. Example 7

[0047] This example discloses a composite current collector, which includes a middle support layer and the copper foil described in Example 6 on both sides of the support layer. Example 8

[0048] This example discloses the application of a hydroxyethyl cellulose mixture in the preparation of copper foil production additives or electrolytic solutions. The hydroxyethyl cellulose mixture is formed by mixing hydroxyethyl celluloses with different viscosities / molecular weights. The hydroxyethyl cellulose mixture is formed by mixing hydroxyethyl celluloses with different viscosities within the viscosity range of 15,000 to 100,000 mPa·s. The copper foil production additive is an electrolytic copper foil production additive.

[0049] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the technical solutions of the present invention, rather than limitations on the specific implementation manners of the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the claims of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. An additive applied to the production of electrolytic copper foil, characterized in that, The components of the additive in the electrolyte include: Hydroxyethyl cellulose mixture 20 - 40 ppm; The hydroxyethyl cellulose mixture is formed by mixing hydroxyethyl celluloses with different viscosities.

2. The additive according to claim 1, characterized in that, The hydroxyethyl cellulose mixture includes at least hydroxyethyl celluloses with viscosities differing by more than 1000 mPa·s.

3. The additive according to claim 1, wherein The hydroxyethyl cellulose mixture is formed by mixing hydroxyethyl celluloses with different viscosities within the viscosity range of 15000 - 100000 mPa·s.

4. The additive according to claim 1, wherein The copper foil is an ultra-thin copper foil with a thickness of 1.5 - 15 μm.

5. The additive according to any one of claims 1 to 4, characterized in that, The components of the additive in the electrolyte further include: Brightener 5 - 20 ppm; And / or, wetting agent 5 - 20 ppm; The brightener includes one or more of the group consisting of sulfur-containing organic brighteners, 4-phenylimidazole, 2-benzylimidazoline, hexylbenzylamine salt, or diphenylvinylpyridine; The wetting agent includes one or more of the group consisting of polyethylene glycol, octylphenol polyethylene glycol ether, or polypropylene glycol.

6. The additive according to claim 5, characterized in that, The brightener is sodium poly(dithiopropane sulfonate), and the wetting agent is polyethylene glycol.

7. An electrolytic solution for preparing copper foil, characterized in that, It includes: Electrolyte mother liquor, and the additive according to any one of claims 1 - 6; The electrolyte mother liquor includes: Cu 2+ 65~90 g / L; H2SO4 75 - 100 g / L; Cl - 20 - 30 ppm.

8. An electrolytic copper foil production process, characterized in that, It includes steps: A1. Prepare the electrolytic solution according to claim 7, and supply the electrolytic solution between the anode structure and the cathode structure; A2. Circulate the electrolytic solution at 45 - 55 °C and an anode structure current density of 40 - 70 A / dm² for electrolytic copper foil production to obtain the corresponding electrolytic copper foil.

9. A copper foil, characterized in that, Prepared by electroplating with the electrolytic solution according to claim 7 or obtained by the electrolytic copper foil production process according to claim 8.

10. Use of a hydroxyethyl cellulose mixture in the preparation of a copper foil production additive or an electrolytic solution, wherein the hydroxyethyl cellulose mixture is formed by mixing hydroxyethyl celluloses with different viscosities.