High-tensile copper foil electrolyte additive composition, copper electrolyte and preparation method of electrolytic copper foil

Abstract

The invention provides a high-tensile copper foil electrolyte additive composition, a copper electrolyte and a preparation method of an electrolytic copper foil, and belongs to the technical field of electrolytic copper foils. The high-tensile copper foil electrolyte additive composition provided by the invention comprises the sulfur-containing compound and ethylene thiourea, and a complex formed by copper ions and ethylene thiourea can provide a binding site for a sulfur-containing organic matter, so that the mechanical property of an electrolytic copper foil can be improved. By means of polyethylene glycol and chlorine salt, original uneven copper plating distribution becomes uniform, and the flattening capacity of the electrolytic copper foil is improved; a nitrogen-containing compound is used for improving the flatness of the electrolytic copper foil and improving the tensile strength of the electrolytic copper foil; the hydroxyethyl cellulose is added, so that the roughness of the electrolytic copper foil is reduced, the compactness is improved, the generation of holes is reduced, and the tensile strength of the electrolytic copper foil is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic copper foil, and in particular to a preparation method of a high-tensile-strength copper foil electrolyte additive composition, a copper electrolyte and an electrolytic copper foil. Background Art

[0002] Copper foil, as the current collector for the negative electrode of lithium-ion batteries, carries the responsibility of electron transport. To ensure close contact between the active material and the current collector, maintain battery capacity, and improve safety, copper foil must be ultra-thin, have low roughness, and possess high tensile strength and elongation.

[0003] Currently, the most common method for producing copper foil is electrolysis, which requires the addition of additives to the electrolyte to improve its properties. However, commonly used electrolyte additives include sulfur-containing compounds and nitrogen-containing compounds, but the tensile strength of electrolytic copper foil produced using existing techniques is below 400 MPa.

[0004] Therefore, it is urgent to provide an electrolyte additive composition that can obtain high tensile strength copper foil, which has become a difficult problem in the field. Summary of the Invention

[0005] The object of the present invention is to provide a high-tensile strength copper foil electrolyte additive composition, a copper electrolyte and a preparation method of electrolytic copper foil. After electrolysis of the copper electrolyte prepared by the copper foil electrolyte additive composition provided by the present invention, a copper foil with high tensile strength can be obtained.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a high-tensile copper foil electrolyte additive composition, which comprises, by weight, 1 to 10 parts of a sulfur-containing compound, 1 to 5 parts of ethylene thiourea, 0.5 to 5 parts of polyethylene glycol, 0.5 to 5 parts of a chloride salt, 1 to 10 parts of hydroxyethyl cellulose, and 10 to 30 parts of a nitrogen-containing compound;

[0008] The sulfur-containing compound includes one or more of a sulfonic acid compound containing a thiol group and a sulfonic acid compound containing a disulfide bond;

[0009] The nitrogen-containing compound includes one or more of gelatin, aminopyridine, pyridine, fatty amine ethoxy sulfonate and bipyridine.

[0010] Preferably, the sulfonic acid compound containing a thiol group includes 2-mercaptoethanesulfonic acid or 3-mercaptopropanesulfonic acid.

[0011] Preferably, the disulfide bond-containing sulfonic acid compound includes dithiodiethanesulfonic acid or taurine disulfide.

[0012] Preferably, the weight average molecular weight of the polyethylene glycol is 6000 to 12000 g / mol.

[0013] Preferably, the viscosity of the hydroxyethyl cellulose at 25° C. is 3000 to 6000 mPa·s.

[0014] The present invention also provides a copper electrolyte comprising copper sulfate, sulfuric acid, an additive composition and water;

[0015] The copper electrolyte has a copper sulfate concentration of 60 to 120 g / L; a sulfuric acid concentration of 100 to 120 g / L; and an additive composition concentration of 0.1 to 10 g / L.

[0016] The additive composition is the high tensile strength copper foil electrolyte additive composition described in the above technical solution.

[0017] The present invention also provides a method for preparing an electrolytic copper foil, comprising: electrolyzing the copper electrolyte described in the above technical solution to obtain the electrolytic copper foil.

[0018] Preferably, the electrolysis temperature is 40-60°C.

[0019] Preferably, the current density of the electrolysis is 50 to 80 A / dm 2 .

[0020] Preferably, the thickness of the electrolytic copper foil is 5 to 10 μm.

[0021] The invention provides a high-tensile copper foil electrolyte additive composition. The components include, by weight, 1 to 10 parts of a sulfur-containing compound, 1 to 5 parts of ethylene thiourea, 0.5 to 5 parts of polyethylene glycol, 0.5 to 5 parts of a chloride salt, 1 to 10 parts of hydroxyethyl cellulose and 10 to 30 parts of a nitrogen-containing compound. The sulfur-containing compound includes one or more of a sulfonic acid compound containing a thiol group and a sulfonic acid compound containing a disulfide bond. The nitrogen-containing compound includes one or more of gelatin, aminopyridine, pyridine, fatty amine ethoxysulfonate and bipyridine. The high-tensile copper foil electrolyte additive composition provided by the present invention includes sulfur-containing compounds and ethylenethiourea, and the sulfur-containing compounds include one or more of sulfonic acid compounds containing thiol groups and sulfonic acid compounds containing disulfide bonds. The complex formed by copper ions and ethylenethiourea can provide binding sites for sulfur-containing organic matter, which is conducive to its formation of an adsorption layer on the (220) crystal surface of copper. The sulfur-containing compound can be adsorbed on the (220) crystal surface of copper, inhibiting the growth of the (220) surface. The slow-growing crystal surface will be retained, so that the (220) texture of copper is improved, and the mechanical properties of the electrolytic copper foil are improved; the present invention uses polyethylene glycol and chloride salts to make the originally uneven distribution of copper plating more uniform, thereby improving the flatness of the electrolytic copper foil; uses nitrogen-containing compounds to improve the flatness of the electrolytic copper foil and improve the tensile strength of the electrolytic copper foil; the present invention adds hydroxyethyl cellulose to reduce the roughness of the electrolytic copper foil, improve the density, reduce the generation of holes, and thus improve the tensile strength of the electrolytic copper foil. The results of the examples show that after electrolysis of the copper electrolyte prepared by the copper foil electrolyte additive composition provided by the present invention, the high tensile strength of the obtained copper foil is above 644 MPa. DETAILED DESCRIPTION

[0022] The present invention provides a high-tensile copper foil electrolyte additive composition, which comprises, by weight, 1 to 10 parts of a sulfur-containing compound, 1 to 5 parts of ethylene thiourea, 0.5 to 5 parts of polyethylene glycol, 0.5 to 5 parts of a chloride salt, 1 to 10 parts of hydroxyethyl cellulose, and 10 to 30 parts of a nitrogen-containing compound;

[0023] The sulfur-containing compound includes one or more of a sulfonic acid compound containing a thiol group and a sulfonic acid compound containing a disulfide bond;

[0024] The nitrogen-containing compound includes one or more of gelatin, aminopyridine, pyridine, fatty amine ethoxy sulfonate and bipyridine.

[0025] In the present invention, unless otherwise specified, the chemical reagents used in the present invention are all commercially available products well known to those skilled in the art.

[0026] The high-tensile copper foil electrolyte additive composition provided by the present invention includes 1 to 10 parts by weight of a sulfur-containing compound. As an embodiment of the present invention, the sulfur-containing compound can be present in 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts by weight.

[0027] In the present invention, the sulfur-containing compound comprises one or more of a sulfonic acid compound containing a thiol group and a sulfonic acid compound containing a disulfide bond. In the present invention, the sulfonic acid compound containing a thiol group preferably comprises 2-mercaptoethanesulfonic acid or 3-mercaptopropanesulfonic acid; and the sulfonic acid compound containing a disulfide bond preferably comprises dithiodiethanesulfonic acid or taurine disulfide. The use of these sulfur-containing compounds in the present invention is more conducive to adsorption on the (220) crystal plane of copper.

[0028] The high-tensile strength copper foil electrolyte additive composition provided by the present invention includes 1 to 5 parts of ethylene thiourea, based on 1 to 10 parts by weight of the sulfur-containing compound. As one embodiment of the present invention, the weight of the ethylene thiourea can be 1 part, 2 parts, 3 parts, 4 parts, or 5 parts. The addition of ethylene thiourea in the present invention forms a complex between copper ions and ethylene thiourea, providing binding sites for sulfur-containing organic matter, thereby facilitating its formation of an adsorption layer on the (220) crystal plane of copper.

[0029] The high-tensile copper foil electrolyte additive composition provided by the present invention includes 0.5 to 5 parts of polyethylene glycol, based on 1 to 10 parts by weight of the sulfur-containing compound. In one embodiment of the present invention, the polyethylene glycol may be present in an amount of 0.5, 1, 2, 3, 4, or 5 parts by weight. The addition of polyethylene glycol and a chloride salt can improve the flatness of the electrolytic copper foil.

[0030] In the present invention, the weight-average molecular weight of the polyethylene glycol is preferably 6,000 to 12,000 g / mol. As one embodiment of the present invention, the weight-average molecular weight of the polyethylene glycol can be 6,000 g / mol, 7,000 g / mol, 8,000 g / mol, 9,000 g / mol, 10,000 g / mol, 11,000 g / mol, or 12,000 g / mol. The use of polyethylene glycol with such a weight-average molecular weight in the present invention is more conducive to grain refinement and improved flatness of the electrolytic copper foil.

[0031] The high-tensile copper foil electrolyte additive composition provided by the present invention includes 0.5 to 5 parts of a chloride salt, based on 1 to 10 parts by weight of the sulfur-containing compound. As one embodiment of the present invention, the chloride salt may be present in an amount of 0.5, 1, 2, 3, 4, or 5 parts by weight. The addition of the chloride salt, in conjunction with polyethylene glycol, can improve the flattening ability of the electrolytic copper foil. In the present invention, the chloride salt preferably includes sodium chloride and / or potassium chloride.

[0032] The high-tensile-strength copper foil electrolyte additive composition provided by the present invention includes 1 to 10 parts by weight of hydroxyethyl cellulose, based on 1 to 10 parts by weight of the sulfur-containing compound. As one embodiment of the present invention, the hydroxyethyl cellulose can be present in 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts by weight. The addition of hydroxyethyl cellulose reduces the roughness of the electrolytic copper foil, improves its density, and reduces void formation, thereby increasing the tensile strength of the electrolytic copper foil.

[0033] In the present invention, the viscosity of the hydroxyethyl cellulose at 25°C is preferably 3000 to 6000 mPa·s. As one embodiment of the present invention, the viscosity of the hydroxyethyl cellulose at 25°C may be 3000 mPa·s, 4000 mPa·s, 5000 mPa·s, or 6000 mPa·s. The hydroxyethyl cellulose of the above viscosity is used in the present invention to achieve better fluidity.

[0034] The high-tensile-strength copper foil electrolyte additive composition provided by the present invention includes 10 to 30 parts of a nitrogen-containing compound, based on 1 to 10 parts by weight of the sulfur-containing compound. In one embodiment of the present invention, the nitrogen-containing compound may be present in an amount of 10, 12, 15, 20, 25, or 30 parts by weight. The addition of the nitrogen-containing compound can improve the flatness of the electrolytic copper foil.

[0035] In the present invention, the nitrogen-containing compound preferably includes one or more of gelatin, aminopyridine, pyridine, fatty amine ethoxy sulfonate and bipyridine, and more preferably gelatin, aminopyridine, pyridine or fatty amine ethoxy sulfonate.

[0036] The present invention also provides a copper electrolyte comprising copper sulfate, sulfuric acid, an additive composition and water.

[0037] In the present invention, the mass concentration of copper sulfate in the copper electrolyte is 60 to 120 g / L. As an embodiment of the present invention, the mass concentration of copper sulfate in the copper electrolyte can be 60 g / L, 70 g / L, 80 g / L, 90 g / L, 100 g / L, 110 g / L or 120 g / L. In the present invention, the copper sulfate provides copper ions, which are deposited to form copper foil through a cathode reduction reaction. The present invention controls the content of copper sulfate within the above range, which can refine the grains, while making the copper deposition uniform, avoiding the formation of microscopic protrusions due to rapid deposition caused by excessive content, reducing surface roughness, and thereby improving the tensile strength of the electrolytic copper foil.

[0038] In the present invention, the mass concentration of sulfuric acid in the copper electrolyte is 100-120 g / L. As an embodiment of the present invention, the mass concentration of sulfuric acid in the copper electrolyte can be 100 g / L, 105 g / L, 110 g / L, 115 g / L, or 120 g / L. In the present invention, the sulfuric acid dissociates into hydrogen ions, improving the conductivity of the electrolyte while maintaining an acidic environment to prevent the formation of copper hydroxide precipitation. It can also inhibit the disordered deposition of copper ions, reduce dendrites, improve surface smoothness, and prevent the oxidation of sulfur-containing compounds. The present invention controls the content of sulfuric acid within the above range, which can further improve the tensile strength of the electrolytic copper foil.

[0039] In the present invention, the mass concentration of the additive composition in the copper electrolyte is 0.1 to 10 g / L. As one embodiment of the present invention, the mass concentration of the additive composition in the copper electrolyte can be 0.1 g / L, 0.5 g / L, 1 g / L, 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L or 10 g / L. In the present invention, the additive composition is the high-tensile copper foil electrolyte additive composition described in the above technical solution, and will not be described in detail here. The present invention significantly improves the tensile strength of the electrolytic copper foil by adding the high-tensile copper foil electrolyte additive composition and utilizing the synergistic effect of each component.

[0040] The present invention also provides a method for preparing an electrolytic copper foil, comprising: electrolyzing the copper electrolyte described in the above technical solution to obtain the electrolytic copper foil.

[0041] In the present invention, the electrolysis temperature is preferably 40-60°C. As one embodiment of the present invention, the electrolysis temperature may be 40°C, 45°C, 50°C, 55°C, or 60°C. The present invention does not particularly limit the electrolysis time, and can be adjusted to achieve a desired thickness of the electrolytic copper foil.

[0042] In the present invention, the current density of the electrolysis is preferably 50 to 80 A / dm 2 As an embodiment of the present invention, the current density of the electrolysis can be 50A / dm 2 、60A / dm 2 , 70A / dm 2 or 80A / dm 2 .

[0043] In the present invention, the thickness of the electrolytic copper foil is 4 to 8 μm. By controlling the electrolysis time, the thickness of the electrolytic copper foil can be kept within the above range. By controlling the electrolysis temperature and current density within the above ranges, the tensile strength of the electrolytic copper foil can be further improved.

[0044] The present invention controls the composition of the copper electrolyte and adds a high-tensile-strength copper foil electrolyte additive composition into the copper electrolyte, thereby improving the tensile strength of the electrolytic copper foil.

[0045] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0046] Example 1

[0047] A high-tensile copper foil electrolyte additive composition comprises, by weight, 3 parts of 2-mercaptoethanesulfonic acid, 2 parts of ethylenethiourea, 1 part of polyethylene glycol (6000 g / mol), 0.5 parts of sodium chloride, 4 parts of hydroxyethyl cellulose (viscosity at 25° C. is 4000 mPa·s), and 10 parts of gelatin.

[0048] Example 2

[0049] A high-tensile copper foil electrolyte additive composition comprises, by weight, 3 parts of 3-mercaptoethanesulfonic acid, 2 parts of ethylenethiourea, 1 part of polyethylene glycol (6000 g / mol), 0.5 part of sodium chloride, 4 parts of hydroxyethyl cellulose (viscosity at 25° C. is 4000 mPa·s), and 10 parts of aminopyridine.

[0050] Example 3

[0051] A high-tensile copper foil electrolyte additive composition comprises, by weight, 5 parts of diethylenetriamine disulfonic acid, 4 parts of ethylenethiourea, 3 parts of polyethylene glycol (6000 g / mol), 1 part of sodium chloride, 5 parts of hydroxyethyl cellulose (viscosity at 25° C. is 4000 mPa·s), and 12 parts of bipyridine.

[0052] Example 4

[0053] A high-tensile copper foil electrolyte additive composition comprises, by weight, 6 parts of taurine disulfide, 4 parts of ethylenethiourea, 4 parts of polyethylene glycol (6000 g / mol), 1 part of sodium chloride, 6 parts of hydroxyethyl cellulose (viscosity at 25°C is 4000 mPa·s), and 15 parts of bipyridine.

[0054] Comparative Example 1

[0055] A copper foil electrolyte additive composition comprises, by weight, 3 parts of 2-mercaptoethanesulfonic acid, 1 part of polyethylene glycol (6000 g / mol), 0.5 part of sodium chloride, 4 parts of hydroxyethyl cellulose (viscosity at 25° C. is 4000 mPa·s), and 10 parts of gelatin.

[0056] Comparative Example 2

[0057] A copper foil electrolyte additive composition comprises, by weight, 2 parts of ethylene thiourea, 1 part of polyethylene glycol (6000 g / mol), 0.5 parts of sodium chloride, 4 parts of hydroxyethyl cellulose (viscosity at 25° C. is 4000 mPa·s), and 10 parts of gelatin.

[0058] Comparative Example 3

[0059] A copper foil electrolyte additive composition comprises, by weight, 3 parts of 2-mercaptoethanesulfonic acid, 2 parts of ethylenethiourea, 1 part of polyethylene glycol (6000 g / mol), 0.5 parts of sodium chloride, and 4 parts of hydroxyethyl cellulose (viscosity at 25° C. is 4000 mPa·s).

[0060] Example 5

[0061] A copper electrolyte comprising copper sulfate, sulfuric acid, the high-tensile strength copper foil electrolyte additive composition provided in Example 1, and water;

[0062] The mass concentration of copper sulfate in the copper electrolyte is 65 g / L; the mass concentration of sulfuric acid is 100 g / L; and the mass concentration of the additive composition is 0.1 g / L.

[0063] Example 6

[0064] A copper electrolyte comprising copper sulfate, sulfuric acid, the high-tensile strength copper foil electrolyte additive composition provided in Example 2, and water;

[0065] The mass concentration of copper sulfate in the copper electrolyte is 65 g / L; the mass concentration of sulfuric acid is 100 g / L; and the mass concentration of the additive composition is 0.1 g / L.

[0066] Example 7

[0067] A copper electrolyte comprising copper sulfate, sulfuric acid, the high-tensile strength copper foil electrolyte additive composition provided in Example 3, and water;

[0068] The mass concentration of copper sulfate in the copper electrolyte is 65 g / L; the mass concentration of sulfuric acid is 100 g / L; and the mass concentration of the additive composition is 0.1 g / L.

[0069] Example 8

[0070] A copper electrolyte comprising copper sulfate, sulfuric acid, the high-tensile strength copper foil electrolyte additive composition provided in Example 4, and water;

[0071] The mass concentration of copper sulfate in the copper electrolyte is 65 g / L; the mass concentration of sulfuric acid is 100 g / L; and the mass concentration of the additive composition is 0.1 g / L.

[0072] Example 9

[0073] A copper electrolyte comprising copper sulfate, sulfuric acid, the high-tensile strength copper foil electrolyte additive composition provided in Example 1, and water;

[0074] The mass concentration of copper sulfate in the copper electrolyte is 80 g / L; the mass concentration of sulfuric acid is 110 g / L; and the mass concentration of the additive composition is 2 g / L.

[0075] Example 10

[0076] A copper electrolyte comprising copper sulfate, sulfuric acid, the high-tensile strength copper foil electrolyte additive composition provided in Example 1, and water;

[0077] The mass concentration of copper sulfate in the copper electrolyte is 100 g / L; the mass concentration of sulfuric acid is 120 g / L; and the mass concentration of the additive composition is 3 g / L.

[0078] Comparative Example 4

[0079] A copper electrolyte, comprising copper sulfate, sulfuric acid, the high-tensile strength copper foil electrolyte additive composition provided in Comparative Example 1, and water;

[0080] The mass concentration of copper sulfate in the copper electrolyte is 100 g / L; the mass concentration of sulfuric acid is 120 g / L; and the mass concentration of the additive composition is 3 g / L.

[0081] Comparative Example 5

[0082] A copper electrolyte, comprising copper sulfate, sulfuric acid, the high-tensile strength copper foil electrolyte additive composition provided in Comparative Example 2, and water;

[0083] The mass concentration of copper sulfate in the copper electrolyte is 100 g / L; the mass concentration of sulfuric acid is 120 g / L; and the mass concentration of the additive composition is 3 g / L.

[0084] Comparative Example 6

[0085] A copper electrolyte, comprising copper sulfate, sulfuric acid, the high-tensile strength copper foil electrolyte additive composition provided in Comparative Example 3, and water;

[0086] The mass concentration of copper sulfate in the copper electrolyte is 100 g / L; the mass concentration of sulfuric acid is 120 g / L; and the mass concentration of the additive composition is 3 g / L.

[0087] Example 11

[0088] A method for preparing electrolytic copper foil: electrolyzing the copper electrolyte provided in Example 5 at a temperature of 50°C and a current density of 50A / dm 2 The thickness of the electrolytic copper foil is 5 μm, and an electrolytic copper foil is obtained.

[0089] Example 12

[0090] A method for preparing electrolytic copper foil: electrolyzing the copper electrolyte provided in Example 6 at a temperature of 50°C and a current density of 50A / dm 2 The thickness of the electrolytic copper foil is 5 μm, and an electrolytic copper foil is obtained.

[0091] Example 13

[0092] A method for preparing electrolytic copper foil: electrolyzing the copper electrolyte provided in Example 7 at a temperature of 50°C and a current density of 50A / dm 2 The thickness of the electrolytic copper foil is 5 μm, and an electrolytic copper foil is obtained.

[0093] Example 14

[0094] A method for preparing electrolytic copper foil: electrolyzing the copper electrolyte provided in Example 8 at a temperature of 50°C and a current density of 50A / dm 2 The thickness of the electrolytic copper foil is 5 μm, and an electrolytic copper foil is obtained.

[0095] Example 15

[0096] A method for preparing electrolytic copper foil: electrolyzing the copper electrolyte provided in Example 9 at a temperature of 50°C and a current density of 50A / dm 2 The thickness of the electrolytic copper foil is 5 μm, and an electrolytic copper foil is obtained.

[0097] Example 16

[0098] A method for preparing electrolytic copper foil: electrolyzing the copper electrolyte provided in Example 10 at a temperature of 50°C and a current density of 50A / dm 2 The thickness of the electrolytic copper foil is 5 μm, and an electrolytic copper foil is obtained.

[0099] Comparative Example 7

[0100] A method for preparing electrolytic copper foil: electrolyze the copper electrolyte provided in Comparative Example 4 at a temperature of 50°C and a current density of 50A / dm 2 The thickness of the electrolytic copper foil is 5 μm, and an electrolytic copper foil is obtained.

[0101] Comparative Example 8

[0102] A method for preparing electrolytic copper foil: electrolyze the copper electrolyte provided in Comparative Example 5 at a temperature of 50°C and a current density of 50A / dm 2 The thickness of the electrolytic copper foil is 5 μm, and an electrolytic copper foil is obtained.

[0103] Comparative Example 9

[0104] A method for preparing electrolytic copper foil: electrolyze the copper electrolyte provided in Comparative Example 6 at a temperature of 50°C and a current density of 50A / dm 2 The thickness of the electrolytic copper foil is 5 μm, and an electrolytic copper foil is obtained.

[0105] The tensile strength of the electrolytic copper foils prepared in Examples 11 to 16 and Comparative Examples 7 to 9 was tested according to GB / T 5230-1995. The results are shown in Table 1.

[0106] Table 1 Tensile strength of electrolytic copper foil prepared in Examples 11 to 16 and Comparative Examples 7 to 9

[0107]

[0108] As can be seen from Table 1, there is a synergistic effect between the sulfur-containing compound and ethylenethiourea, which can improve the tensile strength of the electrolytic copper foil. This is because the complex formed by copper ions and ethylenethiourea can provide binding sites for sulfur-containing organic matter, which is conducive to its formation of an adsorption layer on the (220) crystal plane of copper. The sulfur-containing compound can be adsorbed on the (220) crystal plane of copper, inhibiting the growth of the (220) plane. The slow-growing crystal plane will be retained, so that the (220) texture of copper is improved, and the tensile strength of the electrolytic copper foil is improved. The present invention uses polyethylene glycol and chloride salt to make the originally uneven distribution of copper plating more uniform, thereby improving the flatness of the electrolytic copper foil.

[0109] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A high tensile strength copper foil electrolyte additive composition, comprising, by weight: 1-10 parts of sulfur-containing compound, 1-5 parts of ethylenethiourea, 0.5-5 parts of polyethylene glycol, 0.5-5 parts of chloride salt, 1-10 parts of hydroxyethyl cellulose and 10-30 parts of nitrogen-containing compound; The sulfur-containing compound includes one or more of a sulfonic acid compound containing a thiol group and a sulfonic acid compound containing a disulfide bond; The nitrogen-containing compound includes one or more of gelatin, aminopyridine, pyridine, fatty amine ethoxy sulfonate and bipyridine.

2. The high tensile strength copper foil electrolyte additive composition according to claim 1, characterized in that: The sulfonic acid compound containing a thiol group includes 2-mercaptoethanesulfonic acid or 3-mercaptopropanesulfonic acid.

3. The high tensile strength copper foil electrolyte additive composition according to claim 1, characterized in that: The sulfonic acid compound containing a disulfide bond includes dithiodiethanesulfonic acid or taurine disulfide.

4. The high tensile strength copper foil electrolyte additive composition according to claim 1, characterized in that: The weight average molecular weight of the polyethylene glycol is 6000 to 12000 g / mol.

5. The high tensile strength copper foil electrolyte additive composition according to claim 1, characterized in that: The viscosity of the hydroxyethyl cellulose at 25° C. is 3000 to 6000 mPa·s.

6. A copper electrolyte comprising copper sulfate, sulfuric acid, an additive composition and water; The copper electrolyte has a copper sulfate concentration of 60 to 120 g / L; a sulfuric acid concentration of 100 to 120 g / L; and an additive composition concentration of 0.1 to 10 g / L. The additive composition is the high tensile strength copper foil electrolyte additive composition according to any one of claims 1 to 5.

7. A method for preparing an electrolytic copper foil, comprising: The copper electrolyte according to claim 6 is electrolyzed to obtain an electrolytic copper foil.

8. The preparation method according to claim 7, characterized in that The electrolysis temperature is 40-60°C.

9. The preparation method according to claim 7, characterized in that The current density of the electrolysis is 50 to 80 A / dm 2 .

10. The preparation method according to claim 7, characterized in that The thickness of the electrolytic copper foil is 5 to 10 μm.

Images