Electrolyte for producing an extremely thin copper foil and method for producing an extremely thin copper foil

Abstract

The application discloses an electrolyte for preparing an extremely thin copper foil and a preparation method of the extremely thin copper foil. The electrolyte comprises Cu with a concentration of 50-80 g / L 2+ , H2SO4 with a concentration of 100-160 g / L, chloride ions with a concentration of 1-10 mg / L, polyethylene glycol (PEG) with a concentration of 1-10 mg / L, fatty alcohol polyoxyethylene ether with a concentration of 20-120 mg / L, polythio organic sulfonic acid with a concentration of 1-10 mg / L, mercapto alkyl imidazoline with a concentration of 1-10 mg / L and pure water. The application controls the concentrations of various components and compounding of various additives, so that the various additives are synergistic, the crystal growth is controlled, the crystal grains are refined, the surface tension is reduced, and the impurity adsorption is inhibited, thereby preparing a copper foil with excellent film forming property, high mechanical strength and extremely thin thickness, and the copper foil can be smoothly rolled without breaking.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultra-thin copper foil, in particular to an electrolyte for preparing ultra-thin copper foil and a method for preparing ultra-thin copper foil using the same. BACKGROUND

[0002] As a new emerging comprehensive economic form, the low-altitude economy has been rapidly developing in the whole industry chain in the global range in recent years. Among them, the electric vertical take-off and landing aircraft (eVTOL) has shown a rapid development momentum. In addition, the rapid development of new energy vehicles has higher requirements for the safety, stability, light weight and energy density of the battery system. As the current collector of the negative electrode of the lithium ion battery, the copper foil plays an important role in the battery. By using thinner copper foils with good quality, the energy density of the battery can be improved, the battery performance can be enhanced, and the safety of the battery can be ensured.

[0003] In the prior art, the thickness of the copper foil is developed from 8 μm to 6 μm, or even thinner than 4.5 μm. However, the thinner the copper foil, the poorer the film-forming property, the rougher the surface, the more pinholes and the lower the mechanical strength, which makes it difficult to process the subsequent process. Therefore, the existing technology of thinning the copper foil has the problems of poor film-forming property and low mechanical strength, which limits the thickness reduction and cannot achieve thinner thickness. In order to prepare ultra-thin high-strength copper foil, it is urgent to develop a new type of electrolyte formula and a method for preparing ultra-thin high-strength copper foil using the same. SUMMARY

[0004] The purpose of the embodiment of the present application is to provide an electrolyte. By compounding various additives and controlling the content of each component, the various additives are complexed and synergized with each other, the crystal growth is controlled, the grain size is refined, the surface tension is reduced, and the impurity adsorption is inhibited, so as to prepare a copper foil with excellent film-forming property, high mechanical strength and extremely thin thickness, and the copper foil can be smoothly rolled without breaking.

[0005] To achieve the above-mentioned purpose, the embodiment of the present application provides an electrolyte for preparing ultra-thin copper foil, which comprises CuSO4 with a concentration of 50-80 g / L, H2SO4 with a concentration of 100-160 g / L, chloride ions with a concentration of 1-10 mg / L, polyethylene glycol PEG with a concentration of 1-10 mg / L, fatty alcohol polyoxyethylene ether with a concentration of 20-120 mg / L, polysulfur organic sulfonic acid with a concentration of 1-10 mg / L, mercaptoalkylimidazoline with a concentration of 1-10 mg / L and pure water. 2+

[0006] As an improvement of the above-mentioned scheme, the carbon chain length of the fatty alcohol polyoxyethylene ether is C16-C18.

[0007] As an improvement of the above-mentioned scheme, the number of ethylene oxide addition of the fatty alcohol polyoxyethylene ether is 7-10. ​

[0008] As an improvement of the above scheme, the polythio organic sulfonic acid is sodium polydithiopropyl sulfonate.

[0009] As an improvement of the above scheme, the conductivity of the pure water is ≤0.2 μS / cm.

[0010] As an improvement of the above scheme, the mass ratio of the chloride ion, the polyethylene glycol and the mercapto alkyl imidazoline is (1-1.8):(1-3):(1.5-2).

[0011] As an improvement of the above scheme, the Cu 2+ The concentration of H2SO4 is 110-140 g / L, the concentration of chloride ion is 3-6 mg / L, the concentration of polyethylene glycol PEG is 3-6 mg / L, the concentration of fatty alcohol polyoxyethylene ether is 40-100 mg / L, the concentration of polythio organic sulfonic acid is 3-6 mg / L, and the concentration of mercapto alkyl imidazoline is 2-6 mg / L.

[0012] The application also provides a manufacturing method of the ultra-thin copper foil, which adopts the electrolyte of any one of the above embodiments and comprises the following steps:

[0013] 1) preparing an additive concentrated solution;

[0014] 2) adding the metal copper into a copper dissolving tank containing sulfuric acid to dissolve the copper and prepare a copper sulfate solution;

[0015] 3) filtering the copper sulfate solution, cooling, mixing the additive concentrated solution with the copper sulfate solution to obtain the electrolyte, and pumping the electrolyte into an anode tank;

[0016] 4) preparing the copper foil by a cathode titanium roller in the electrolytic tank.

[0017] As an improvement of the above scheme, the current density of the step 4) is 5-20 A / dm 2 .

[0018] As an improvement of the above scheme, an anti-oxidation treatment is performed after the step 4), wherein the medicine solution of the anti-oxidation treatment comprises a benzotriazole aqueous solution with a concentration of 0.5-1.5 g / L.

[0019] Compared with the prior art, the electrolyte for preparing an ultra-thin copper foil provided by the application has the beneficial effects that: by compounding and controlling the content of various additives, the various additives are combined and synergized with each other, the grain growth is controlled, the grain is refined, the grain size reaches the nanometer level, the surface tension can be reduced, the impurity adsorption can be inhibited, and thus an ultra-thin copper foil with excellent film-forming property, high mechanical strength and extremely thin thickness can be prepared, and the copper foil can be successfully rolled without breaking. The problems of poor film-forming property, low mechanical strength, difficulty in subsequent process, limited thickness reduction and inability to achieve thinner thickness in the prior art are solved. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a manufacturing process diagram of an ultra-thin copper foil provided by an embodiment of the application.

[0021] Figure 2 is a scanning electron microscope photo (5000x) of an ultra-thin copper foil obtained by an electrolyte provided by an embodiment of the application. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments of the application. The purpose of providing these embodiments is to make the disclosure of the application more thorough and comprehensive. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0023] In the description of the present application, the terms "first", "second", "third" and the like are only used for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second", "third" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0024] In the description of the application, it is necessary to point out that, unless otherwise explicitly defined and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. The terms "vertical", "horizontal", "left", "right", "up", "down" and similar expressions used herein are for the purpose of illustration only, and are not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application. The term "and / or" used herein includes any and all combinations of one or more related listed items. The specific meanings of the above terms in the application can be understood by the person skilled in the art.

[0025] In the description of the application, it is necessary to point out that, unless otherwise defined, all technical and scientific terms used in the application are the same as the meanings commonly understood by the person skilled in the art. The terms used in the specification of the application are only for the purpose of describing the specific embodiments, and are not intended to limit the application. The specific meanings of the above terms in the application can be understood by the person skilled in the art.

[0026] The first aspect of the embodiment of the application provides an electrolyte for preparing an ultra-thin copper foil, characterized in that it comprises Cu 2+ with a concentration of 50-80 g / L, H2SO4 with a concentration of 100-160 g / L, chloride ions with a concentration of 1-10 mg / L, polyethylene glycol PEG with a concentration of 1-10 mg / L, fatty alcohol polyoxyethylene ether with a concentration of 20-120 mg / L, polysulfur organic sulfonic acid with a concentration of 1-10 mg / L, mercaptoalkylimidazoline with a concentration of 1-10 mg / L and pure water.

[0027] In the embodiment of the application, Cu 2+ is the raw material of the electrochemical reaction, realizes metal deposition, controls grain growth, and by limiting the concentration of Cu 2+ to 50-80 g / L, the coarse grains caused by too high Cu 2+ concentration are avoided, so that the copper foil surface is rough and the thickness is thick; at the same time, the copper foil is not uniform and pinholes are produced due to too low Cu 2+ concentration and insufficient Cu 2+ supply and slow deposition rate. Therefore, by limiting the concentration of Cu 2+ to 50-80 g / L, the grain growth of the copper foil can be better controlled, and a copper foil with uniform thickness can be prepared. Alternatively, Cu 2+The concentration can be any one of 50 g / L, 55 g / L, 60 g / L, 65 g / L, 70 g / L, 75 g / L, 80 g / L or an interval formed by any two of them.

[0028] In the embodiment of the present application, H2SO4 controls the conductivity of the electrolyte, maintains the stability of Cu 2+ , and has a synergistic effect with the additive. By limiting the concentration of H2SO4 to 100-160 g / L, the electrolyte conductivity is not too low to affect the deposition of copper foil, and the electrolyte conductivity is not too high to inhibit the migration of Cu 2+ and reduce the deposition efficiency. Therefore, by limiting the concentration of H2SO4 to 100-160 g / L, the effect of Cu 2+ can be better played. Alternatively, the concentration of H2SO4 can be any one of 100 g / L, 110 g / L, 120 g / L, 130 g / L, 140 g / L, 150 g / L, 160 g / L or an interval formed by any two of them.

[0029] It is worth noting that the chloride ion, polyethylene glycol and mercaptoalkylimidazoline in the embodiment of the present application have a synergistic effect on each other, which can refine the crystal grains and prepare high-strength copper foil. By limiting the concentrations of chloride ion, polyethylene glycol PEG and mercaptoalkylimidazoline to 1-10 mg / L, 1-10 mg / L and 1-10 mg / L respectively, the synergistic effect can be achieved. If the concentrations are too low, the synergistic effect cannot be achieved, or if the concentrations are too high, it is difficult to control the grain size. Therefore, by limiting the concentrations of chloride ion, polyethylene glycol PEG and mercaptoalkylimidazoline to 1-10 mg / L, 1-10 mg / L and 1-10 mg / L respectively, the crystal grains with a size of nanometer can be prepared, and high-strength copper foil can be achieved. Alternatively, the concentration of chloride ion can be any one of 1 mg / L, 2 mg / L, 5 mg / L, 7 mg / L, 10 mg / L or an interval formed by any two of them, the concentration of polyethylene glycol PEG can be any one of 1 mg / L, 2 mg / L, 5 mg / L, 7 mg / L, 10 mg / L or an interval formed by any two of them, and the concentration of mercaptoalkylimidazoline can be any one of 1 mg / L, 2 mg / L, 5 mg / L, 7 mg / L, 10 mg / L or an interval formed by any two of them.

[0030] Further, in the embodiment of the present application, the fatty alcohol polyoxyethylene ether is added, by limiting the concentration of the fatty alcohol polyoxyethylene ether to 20-120 mg / L, the copper foil cannot be formed due to poor wettability caused by too low concentration, and the deposition efficiency is reduced due to the formation of an adsorption film on the cathode surface caused by too high concentration. Therefore, by limiting the concentration of the fatty alcohol polyoxyethylene ether to 20-120 mg / L, the copper foil can be easily formed, and the mechanical properties are enhanced. Alternatively, the concentration of the fatty alcohol polyoxyethylene ether can be any one of 20 mg / L, 40 mg / L, 60 mg / L, 80 mg / L, 100 mg / L, and 120 mg / L or an interval formed by any two of them.

[0031] Further, in the embodiment of the present application, the polysulfur organic sulfonic acid is added, by limiting the concentration of the polysulfur organic sulfonic acid to 1-10 mg / L, too low concentration will cause too many coarse crystals, affecting the surface quality of the copper foil, and too high concentration will form an adsorption film, reducing the deposition efficiency. Therefore, by limiting the concentration of the polysulfur organic sulfonic acid to 1-10 mg / L, the crystal grains can be further refined, and a high flatness copper foil can be prepared. Preferably, the polysulfur organic sulfonic acid is sodium polydithiopropyl sulfone, which can inhibit burrs and is beneficial to the formation of an ultra-thin copper foil, and can produce excellent synergistic effect with chloride ions and polyethylene glycol to form an ultra-thin copper foil with a smooth surface and high brightness.

[0032] Further, pure water is a solvent in the electrolyte, which plays a role in dissolving electrolytes, adjusting ion concentration, and maintaining the stability of the electrolyte. At the same time, the conductivity of pure water directly determines the quality of the copper foil. The higher the conductivity of pure water, the more impurities in the electrolyte, which is easy to cause abnormal copper foil quality. Preferably, the conductivity of the pure water is ≤0.2 μS / cm.

[0033] In the embodiment, by compounding various additives and controlling the content of each component, the various additives are complexed and synergized with each other, the crystal growth is controlled, the crystal grains are refined, the surface tension is reduced, and the impurity adsorption is inhibited, so that an ultra-thin copper foil with excellent film-forming property, high mechanical strength, and smooth rolling is prepared. The problems of poor film-forming property and low mechanical strength of the copper foil in the prior art are solved, and the copper foil can be easily processed in the subsequent process, the thickness reduction is limited, and the copper foil can be made thinner.

[0034] As a preferred scheme, the Cu 2+ The concentration of H2SO4 is 55-70 g / L, the concentration of H2SO4 is 110-140 g / L, the concentration of chloride ions is 3-6 mg / L, the concentration of polyethylene glycol PEG is 3-6 mg / L, the concentration of fatty alcohol polyoxyethylene ether is 40-100 mg / L, the concentration of polysulfur organic sulfonic acid is 3-6 mg / L, and the concentration of mercaptoalkylimidazoline is 2-6 mg / L.

[0035] It is worth mentioning that the embodiment of the present application further limits the concentration of each component of the electrolyte, so that the synergistic effect between each component is optimized, and a copper foil with excellent film-forming property, high mechanical strength, extremely thin and uniform thickness, smooth and flat surface, and high brightness can be prepared.

[0036] As a preferred solution, the carbon chain length of the fatty alcohol polyoxyethylene ether is C16-C18.

[0037] It is worth mentioning that the embodiment of the present application further limits the carbon chain length of the fatty alcohol polyoxyethylene ether to C16-C18, for example, the carbon chain length is C16, C17, or C18. The fatty alcohol polyoxyethylene ether molecules are more easily attracted to each other and aggregated, and can form a copper foil with a more compact structure and excellent mechanical properties.

[0038] As a preferred solution, the number of ethylene oxide additions of the fatty alcohol polyoxyethylene ether is 7-10.

[0039] It is worth mentioning that the embodiment of the present application further limits the number of ethylene oxide additions of the fatty alcohol polyoxyethylene ether to 7-10, preferably 9. The surface activity is extremely strong, which can better reduce the surface tension of the electrolyte, make the electrolyte uniformly spread on the electrode surface, and be conducive to forming a thin and uniform copper foil with excellent mechanical properties.

[0040] As a preferred solution, the mass ratio of the chloride ion to the polyethylene glycol and the mercaptoalkylimidazoline is (1-1.8):(1-3):(1.5-2).

[0041] It is worth mentioning that the embodiment of the present application further limits the mass ratio of the chloride ion to the polyethylene glycol and the mercaptoalkylimidazoline to (1-1.8):(1-3):(1.5-2), and the preferred ratio is (1.3-1.5):(1.5-2):(1.7-1.8). The chloride ion, the polyethylene glycol, and the mercaptoalkylimidazoline have a strong synergistic effect, which can prepare a fine-grained, flat, and high-brightness copper foil, and the deposition rate of the copper foil is greatly improved.

[0042] The second aspect of the embodiment of the present application provides a method for manufacturing an extremely thin copper foil, as shown in Figure 1 , Figure 1 is a flow chart of the manufacturing process of the extremely thin copper foil according to the embodiment of the present application. The specific steps include the following steps:

[0043] S1: preparing an additive concentrate;

[0044] S2: adding the metal copper into a copper dissolving tank containing sulfuric acid to dissolve the copper and prepare a copper sulfate solution;

[0045] S3: filtering the copper sulfate solution, cooling it, mixing the additive concentrate with the copper sulfate solution to obtain an electrolyte, and pumping it into an electrolytic anode tank.

[0046] S4: producing copper foil in the electrolytic cell by cathode titanium roller.

[0047] It is worth mentioning that the additive of step S1 refers to the components including polyethylene glycol PEG 1~10 mg / L, fatty alcohol polyoxyethylene ether 20~120 mg / L, polysulfur organic sulfonic acid 1~10 mg / L, and mercaptoalkyl imidazoline 1~10 mg / L; the copper dissolving temperature of step 2 is preferably 60~80℃; the cooling temperature of step 3 is 25~40℃, preferably 30~35℃.

[0048] As a preferred solution, the current density of step S4 is 5~20 A / dm 2 , preferably 8~15 A / dm 2 .

[0049] As a preferred solution, a method for producing an ultra-thin copper foil comprises a step S5 of anti-oxidation treatment after step S4, wherein the anti-oxidation treatment solution comprises a benzotriazole aqueous solution with a concentration of 0.5~1.5 g / L. Figure 2 As shown in Figure 2 , it is a scanning electron microscope photo (5000x) of an ultra-thin copper foil obtained by an electrolyte provided by an embodiment of the present application.

[0050] The electrolyte for producing an ultra-thin copper foil and the method for producing an ultra-thin copper foil provided by the embodiments of the present application have the beneficial effects that: the electrolyte for producing an ultra-thin copper foil provided by the present application, through the compounding and content control of multiple additives, makes the various additives synergize with each other, controls the crystal growth, refines the grains, reduces the surface tension, and inhibits the impurity adsorption, so as to produce a copper foil with excellent film-forming property, high mechanical strength, extremely thin thickness, and smooth and high-brightness surface, which can be successfully rolled without breaking. Meanwhile, the electrolyte of the present application can produce a high-brightness copper foil with smooth and delicate surface. The problems of poor film-forming property, rough surface, and low mechanical strength of the copper foil in the prior art, which lead to the difficulty in subsequent process, thickness reduction limitation, and the inability to achieve thinner thickness, are solved.

[0051] In order to embody the beneficial effects of the electrolyte for producing an ultra-thin copper foil and the method for producing an ultra-thin copper foil provided by the embodiments of the present application, the following will be described in combination with several examples and comparative examples.

[0052] Example 1

[0053] The method for producing an ultra-thin copper foil comprises the steps of copper dissolving, electrolytic foil production, and anti-oxidation treatment. Before the electrolytic foil production step, the electrolyte obtained in the copper dissolving step is added with the additive combination.

[0054] The copper dissolving solution step is as follows: copper raw material is added to a copper dissolving tank for copper dissolving, the copper ion content is controlled at 67 g / L, the sulfuric acid content is controlled at 125 g / L, and the chloride ion content is controlled at 3 mg / L.

[0055] Further, impurities are removed through a filter; 60 mg / L of fatty alcohol polyoxyethylene ether, 5 mg / L of sodium polydithiobis propane sulfonate, 3 mg / L of mercapto alkyl imidazoline, and 3 mg / L of polyethylene glycol are added to form an electrolyte solution, which is pumped to an electrolytic anode tank for electrolytic foil production.

[0056] The process conditions of the electrolytic foil production step are as follows: the electrolyte solution is heated to 35℃, the current density is 15 A / dm 2 Then, the original copper foil is prepared through electrolysis by a cathode roller.

[0057] Further, the anti-oxidation treatment is performed in 0.5-1.5 g / L of benzotriazole aqueous solution.

[0058] Example 2

[0059] The preparation method of the ultra-thin copper foil comprises a copper dissolving solution step, an electrolytic foil production step, and an anti-oxidation treatment step, and the additive combination is added to the electrolyte solution obtained in the copper dissolving solution step before the electrolytic foil production step.

[0060] The copper dissolving solution step is as follows: copper raw material is added to a copper dissolving tank for copper dissolving, the copper ion content is controlled at 63 g / L, the sulfuric acid content is controlled at 128 g / L, and the chloride ion content is controlled at 3 mg / L.

[0061] Further, impurities are removed through a filter; 80 mg / L of fatty alcohol polyoxyethylene ether, 5 mg / L of sodium polydithiobis propane sulfonate, 4 mg / L of mercapto alkyl imidazoline, and 3 mg / L of polyethylene glycol are added to form an electrolyte solution, which is pumped to an electrolytic anode tank for electrolytic foil production.

[0062] The process conditions of the electrolytic foil production step are as follows: the electrolyte solution is heated to 35℃, the current density is 12 A / dm 2 Then, the original copper foil is prepared through electrolysis by a cathode roller.

[0063] Further, the anti-oxidation treatment is performed in 0.5-1.5 g / L of benzotriazole aqueous solution.

[0064] Example 3

[0065] The preparation method of the ultra-thin copper foil comprises a copper dissolving solution step, an electrolytic foil production step, and an anti-oxidation treatment step, and the additive combination is added to the electrolyte solution obtained in the copper dissolving solution step before the electrolytic foil production step.

[0066] The copper dissolving step is as follows: copper raw material is added to a copper dissolving tank for copper dissolving, the copper ion content is controlled at 60 g / L, the sulfuric acid content is controlled at 113 g / L, and the chloride ion content is controlled at 6 mg / L.

[0067] Further, impurities are removed through a filter; 100 mg / L of fatty alcohol polyoxyethylene ether, 6 mg / L of sodium polydithiobis propane sulfonate, 6 mg / L of mercapto alkyl imidazoline, and 6 mg / L of polyethylene glycol are added to form an electrolyte solution, which is pumped to an electrolysis anode tank for electrolytic foil production.

[0068] The process conditions of the electrolytic foil production step are as follows: the electrolyte solution is heated to 35°C, the current density is 10 A / dm 2 Next, the original copper foil is prepared through electrolysis by a cathode roller.

[0069] Further, the anti-oxidation treatment is performed in 0.5-1.5 g / L of benzotriazole aqueous solution.

[0070] Example 4

[0071] The method for preparing the extremely thin copper foil comprises the steps of copper dissolving, electrolytic foil production, and anti-oxidation treatment, and the additive combination described above is added to the electrolyte solution obtained in the copper dissolving step before the electrolytic foil production step.

[0072] The copper dissolving step is as follows: copper raw material is added to a copper dissolving tank for copper dissolving, the copper ion content is controlled at 52 g / L, the sulfuric acid content is controlled at 118 g / L, and the chloride ion content is controlled at 6 mg / L.

[0073] Further, impurities are removed through a filter; 100 mg / L of fatty alcohol polyoxyethylene ether, 6 mg / L of sodium polydithiobis propane sulfonate, 6 mg / L of mercapto alkyl imidazoline, and 6 mg / L of polyethylene glycol are added to form an electrolyte solution, which is pumped to an electrolysis anode tank for electrolytic foil production.

[0074] The process conditions of the electrolytic foil production step are as follows: the electrolyte solution is heated to 35°C, the current density is 8 A / dm 2 , and the original copper foil is prepared through electrolysis by a cathode roller.

[0075] Further, the anti-oxidation treatment is performed in 0.5-1.5 g / L of benzotriazole aqueous solution.

[0076] Comparative Example 1

[0077] Copper raw material is added to a copper dissolving tank for copper dissolving, the copper ion content is controlled at 60 g / L, the sulfuric acid content is controlled at 113 g / L, and the chloride ion content is controlled at 6 mg / L.

[0078] Further, impurities are removed by filter; then 150 mg / L fatty alcohol polyoxyethylene ether, 6 mg / L sodium polydithiobis propane sulfonate, 6 mg / L mercapto alkyl imidazoline, 6 mg / L polyethylene glycol are added to form electrolyte, which is pumped to the anode tank for electrolysis of green copper foil.

[0079] The process conditions of the electrolysis of green copper foil step are: the electrolyte is heated to 35℃, the current density is 10 A / dm 2 Then, the original copper foil is prepared by electrolysis through cathode roller.

[0080] Comparative Example 2

[0081] The copper raw material is added to the copper dissolving tank for copper dissolution, the copper ion content is controlled at 60 g / L, the sulfuric acid content is controlled at 113 g / L, and the chloride ion content is controlled at 6 mg / L.

[0082] Further, impurities are removed by filter; then 150 mg / L fatty alcohol polyoxyethylene ether, 6 mg / L sodium polydithiobis propane sulfonate, 6 mg / L mercapto alkyl imidazoline, 6 mg / L polyethylene glycol are added to form electrolyte, which is pumped to the anode tank for electrolysis of green copper foil.

[0083] The process conditions of the electrolysis of green copper foil step are: the electrolyte is heated to 35℃, the current density is 10 A / dm 2 Then, the original copper foil is prepared by electrolysis through cathode roller.

[0084] Comparative Example 3

[0085] The copper raw material is added to the copper dissolving tank for copper dissolution, the copper ion content is controlled at 90 g / L, the sulfuric acid content is controlled at 125 g / L, and the chloride ion content is controlled at 3 mg / L.

[0086] Further, impurities are removed by filter; then 150 mg / L fatty alcohol polyoxyethylene ether, 6 mg / L sodium polydithiobis propane sulfonate, 6 mg / L mercapto alkyl imidazoline, 6 mg / L polyethylene glycol are added to form electrolyte, which is pumped to the anode tank for electrolysis of green copper foil.

[0087] The electrolyte temperature for electrolysis of green copper foil is 52℃, and the current density is 15 A / dm 2 Then, the original copper foil is prepared by electrolysis through cathode roller.

[0088] Comparative Example 4

[0089] The copper raw material is added to the copper dissolving tank for copper dissolution, the copper ion content is controlled at 90 g / L, the sulfuric acid content is controlled at 125 g / L, and the chloride ion content is controlled at 6 mg / L.

[0090] Further, impurities are removed by a filter; 6 mg / L of polydithiopropane sulfonic acid sodium, 6 mg / L of mercaptoalkyl imidazoline, 100 mg / L of collagen, and 20 mg / L of modified hydroxyethyl fiber are added to form an electrolyte, which is pumped to the anode tank for electrolysis.

[0091] The electrolyte temperature for electrolytic copper foil is 52°C, and the current density is 10 A / dm 2 The original copper foil is prepared by electrolysis through a cathode roller.

[0092] As shown in Table 1 below, the process parameters for preparing the ultra-thin copper foil of Examples 1-4 and Comparative Examples 1-4 are as follows.

[0093] Table 1. Process parameters for preparing the ultra-thin copper foil of Examples 1-4 and Comparative Examples 1-4

[0094]

[0095] As shown in Table 2 below, the performance tests of the ultra-thin copper foil of Examples 1-4 and Comparative Examples 1-4 are as follows.

[0096] Table 2. Performance tests of the ultra-thin copper foil of Examples 1-4 and Comparative Examples 1-4

[0097]

[0098] As shown in the summary table above, the copper foils prepared in Examples 1-4 have smooth and high-brightness surfaces, extremely thin thickness, and excellent mechanical strength, and can be successfully rolled without breaking in applications. However, the copper foils of Comparative Examples 1-2 have rough surfaces and low mechanical strength due to the improper concentration of the additives, which cannot be used in production; the copper foils of Comparative Examples 3-4 have poor flatness and brightness, and poor film-forming property due to the lack of fatty alcohol polyoxyethylene ether and polyethylene glycol, and the addition of collagen and modified hydroxyethyl fiber, which makes the copper foil soft and the mechanical strength poor, and cannot be used to prepare ultra-thin copper foils below 4 μm.

[0099] The above is a preferred embodiment of the present application. It should be noted that, for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which are also considered within the scope of protection of the present application.

Claims

1. An electrolyte for producing an extremely thin copper foil, characterized by comprising: Cu at a concentration of 50 to 80 g / L 2+ H2SO4 at a concentration of 100 to 160 g / L, chloride ions at a concentration of 1 to 10 mg / L, polyethylene glycol PEG at a concentration of 1 to 10 mg / L, fatty alcohol polyoxyethylene ether at a concentration of 20 to 120 mg / L, polythio organic sulfonic acid at a concentration of 1 to 10 mg / L, mercaptoalkylimidazoline at a concentration of 1 to 10 mg / L, and pure water; the polythio organic sulfonic acid is polydithiodipropyl sulfone sodium; The mass ratio of the chloride ion, the polyethylene glycol and the mercaptoalkyl imidazoline is (1-1.8):(1-3):(1.5-2).

2. The electrolyte of claim 1, wherein The carbon chain length of the fatty alcohol polyoxyethylene ether is C16-C18.

3. The electrolyte of claim 1, wherein The number of ethylene oxide addition of the fatty alcohol polyoxyethylene ether is 7-10.

4. The electrolyte of claim 1, wherein The conductivity of the pure water is less than or equal to 0.2 μS / cm.

5. The electrolyte according to any one of claims 1 to 3, wherein The Cu 2+ The concentration of H2SO4 is 110-140 g / L, the concentration of chloride ion is 3-6 mg / L, the concentration of polyethylene glycol (PEG) is 3-6 mg / L, the concentration of fatty alcohol polyoxyethylene ether is 40-100 mg / L, the concentration of polysulfur organic sulfonic acid is 3-6 mg / L, and the concentration of mercaptoalkylimidazoline is 5-6 mg / L.

6. A method for producing an extremely thin copper foil, characterized by The manufacturing method adopts the electrolyte of any one of claims 1-5, and comprises the following steps: 1) preparing an additive concentrate; 2) adding copper into a copper dissolving tank containing sulfuric acid to dissolve the copper into copper sulfate solution; 3) filtering the copper sulfate solution, cooling, mixing the additive concentrate with the copper sulfate solution to obtain the electrolyte, and pumping the electrolyte into an anode tank; 4) preparing copper foil by a cathode titanium roller in the electrolysis tank.

7. The method of claim 6, wherein the copper foil is formed to a thickness of 5 to 50 μm. The current density of the step 4) is 5-20 A / dm 2 .

8. The method of claim 6, wherein the copper foil is formed to a thickness of 5 to 50 μm. After the step 4), an anti-oxidation treatment is performed, wherein the medicine solution of the anti-oxidation treatment comprises a benzotriazole aqueous solution with a concentration of 0.5-1.5 g / L.

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