KR20230097312A - Porous copper three-dimensional current collector and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a method for manufacturing a porous copper three-dimensional current collector and a porous copper three-dimensional current collector manufactured therefrom. The method includes the following steps of: (a) producing ink by dissolving polymer resin in a mixture solvent comprising water, an aqueous miscible polar solvent miscible with water, having a boiling point below 100℃ and a vapor pressures of no less than 10 ㎪ at 25℃, and a non-aqueous miscible non-polar solvent dissolved in water to no more than 5 g/L, having a boiling point above 100℃ and having a vapor pressure of less than 10 ㎪ at 25℃; (b) forming a nonconductive structure by coating the ink on copper foil, and then drying the ink; (c) electrolytically copper-plating the surface of the copper foil on which the nonconductive structure has been formed; and (d) manufacturing a porous copper three-dimensional current collector having a surface shape of a dimple structure by removing the nonconductive structure. Therefore, the present invention is capable of improving productivity by enabling process automation and mass production.

Description

Porous copper three-dimensional current collector and manufacturing method thereof {Porous copper three-dimensional current collector and manufacturing method thereof}

The present invention relates to a porous copper three-dimensional current collector and a method for manufacturing the same.

A secondary battery is a device that converts external electrical energy into chemical energy and stores it to generate electricity when needed. There are lead acid batteries, nickel-cadmium batteries (NiCd), nickel hydrogen (NiMH), lithium ion (Li-ion) batteries, and lithium ion polymer batteries (Li-ion polymer).

A lithium secondary battery uses a material capable of reversibly intercalating and deintercalating lithium ions as an anode and a cathode, and inserts an organic electrolyte or a polymer electrolyte solution between the anode and the cathode to enable smooth movement of lithium ions. /A battery in which electrons generated by electrochemical oxidation and reduction reactions that occur when desorbed generate electrical energy.

Lithium secondary battery is the battery with the best performance among commercially available secondary batteries, and is mainly used for large products that require limited volume and light weight, such as smartphones and laptops, that is, portable products. Accordingly, it is applied to electric vehicles and energy storage systems and is being used as a high-output energy source.

On the other hand, the current collector collects electrons generated from the active material (anode and cathode material) of the lithium ion secondary battery (LIB) and transfers them to the external circuit, and at the same time serves as an electrode matrix for electrode active materials, so it is used in electric vehicles and energy storage systems (ESS). It is a key component that can dramatically improve the rapid charging performance of lithium-ion secondary batteries used in mid- to large-sized electronic devices.

There are electrodeposited copper foils and rolled copper foils as current collectors for the negative electrode of secondary batteries. Rolled copper foils were used until the early 1990s, but since then, electrodeposited copper foils with excellent characteristics have been developed and used as current collectors for negative electrodes of secondary batteries.

Electrolytic copper foil is manufactured by electroplating and has a vertical crystal structure, whereas rolled copper foil is manufactured by melting injection (roller/slow cooling) and has a horizontal crystal structure. Accordingly, the electrodeposited copper foil has advantages such as easy thickness control, low price, and high adhesive strength with polyimide, but has disadvantages such as low flexibility and difficulty in various applications. In the case of rolled copper foil, it has the advantage of having a dense crystal structure and high flexibility, but has the disadvantage of being expensive, requiring an oxidation treatment process to create roughness, and making it difficult to manufacture a copper foil having a thin thickness of 1/2 Oz or less.

In addition, electrodeposited copper foil has a wide range of production compared to rolled copper foil and is easy to adjust thickness and physical properties, so it is economically viable and its use as various materials is expanding. However, although rapid charging performance can be greatly improved by efficient transfer of electrons generated in the current collector, research and development and commercialization of fast charging technology for the current collector are still insufficient.

The core characteristics of electrodeposited copper foil used as a current collector for lithium secondary batteries are thickness and surface roughness, and it can be said that it is especially important to reduce the thickness of copper foil. Because the capacity is increased. Key challenges to be overcome when reducing the thickness of electrodeposited copper foil are mechanical strength and wrinkle deformation problems, and recently, the thickness of electrodeposited copper foil for secondary batteries has been developed up to 6 micrometers.

Therefore, the development and application of a three-dimensional current collector can minimize the resistance at the interface by increasing the contact area and binding force between the current collector and the active material, and through this, long lithium ion diffusion distance and low electron transfer, which affect rapid charging performance problem can be overcome.

A foam structure in the form of a film with nano-sized pores is required to be applied to applications such as actual sensors and catalysts. unsuitable for

Recently, attempts have been made to manufacture a porous thin film using an electrolytic plating method in order to overcome the limitations of the conventional metal foam manufacturing method, and during electroplating, high overvoltage accompanied by copper electrodeposition and hydrogen generation reaction Various attempts have been made, such as manufacturing copper foam by an electrolytic plating method by applying copper.

As part of this research, Korean Patent Registration Publication No. 10-2032265 discloses organic porous bodies of polyurethane foam using electroless plating, electrolytic plating, heat treatment to remove organic porous bodies (unsafe combustion-oxidation-sintering heat treatment), partial copper plating or overlapping Porous copper produced through rolling and final rolling has been proposed, but there are problems in productivity due to complexity of the manufacturing process, high process temperature, and inability to automate.

In addition, Korean Patent Registration Publication No. 10-2176482 suggests a method of forming porous copper through a foaming method using plating on the copper surface, but oxidation characteristics of the copper surface structure occur during plating, resulting in additional high temperature and dangerous A reduction process that requires the use of hydrogen gas is required, and this also has a problem in that mass production is difficult.

Therefore, there is an urgent need for a manufacturing method capable of securing a large amount of a porous copper three-dimensional current collector for a negative electrode having uniform porosity.

Republic of Korea Patent Registration No. 10-2032265 (2019.10.08) Republic of Korea Patent Registration No. 10-2176482 (2020.11.03)

In order to solve the above problems, an object of the present invention is to provide a porous copper three-dimensional collector and a method for manufacturing the same, which have uniform porosity and can be mass-produced.

However, the above purpose is exemplary, and the technical spirit of the present invention is not limited thereto.

One aspect of the present invention for achieving the above object is a) water, a water-miscible polar solvent that is completely miscible with water, has a boiling point of less than 100 ° C, and has a vapor pressure of 10 kPa or more at 25 ° C., and 5 Preparing an ink by dissolving a polymer resin in a mixed solvent composed of a non-water miscible non-polar solvent having a boiling point of greater than 100 ° C and a vapor pressure of less than 10 kPa at 25 ° C.; b) forming a non-conductive structure by coating the ink on a copper foil and then drying the ink; c) electroplating the surface of the copper foil on which the non-conductive structure is formed; and d) manufacturing a porous copper three-dimensional current collector having a surface shape of a dimple structure by removing the non-conductive structure.

In the above aspect, the water-miscible polar solvent may be acetone, and the water-miscible non-polar solvent may be toluene.

In the above aspect, the weight ratio of water: water-miscible polar solvent: non-water-miscible non-polar solvent may be 1:2 to 5:0.5 to 1.5.

In the above aspect, the polymer resin may be dissolved in an amount of 0.5 to 5% by weight of the total weight of the ink.

In the above aspect, step b) may be characterized in that the (wet) coating is coated with a thickness of 300 μm or less.

In addition, another aspect of the present invention relates to a porous copper three-dimensional current collector having a surface shape of a dimple structure.

In the other aspect, the average diameter of the dimples may be 10 to 300 μm.

The manufacturing method of the porous copper three-dimensional current collector according to the present invention can effectively manufacture a porous copper three-dimensional current collector having a uniform dimple structure surface structure through a simple method of surface treatment of copper foil with ink and then electrolytic copper plating. It has the advantage of improving productivity by enabling process automation and mass production.

In addition, the porous copper three-dimensional current collector having a surface shape of a dimple structure manufactured through this can increase the contact area and binding force between the current collector and the active material to minimize resistance at the interface, thereby affecting fast charging performance It can overcome the problems of long lithium ion diffusion distance and low electron transport.

1 is a manufacturing process diagram briefly showing a manufacturing method of a porous copper three-dimensional current collector according to the present invention.
2 is a scanning electron microscope (SEM) image of the surface of a porous copper three-dimensional current collector having a surface shape of a dimple structure.
3 is a real picture of copper foil before and after ink coating.
4 is a SEM image of a non-conductive structure.
5 is a rapid charging performance evaluation result of secondary batteries manufactured using the copper current collectors of Example 3 and Comparative Example 1, respectively.

Hereinafter, a porous copper three-dimensional current collector and a manufacturing method thereof according to the present invention will be described in detail. The drawings introduced below are provided as examples so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art. Therefore, the present invention may be embodied in other forms without being limited to the drawings presented below, and the drawings presented below may be exaggerated to clarify the spirit of the present invention. At this time, unless there is another definition in the technical terms and scientific terms used, they have meanings commonly understood by those of ordinary skill in the art to which this invention belongs, and the gist of the present invention in the following description and accompanying drawings Descriptions of well-known functions and configurations that may be unnecessarily obscure are omitted.

One aspect of the present invention is a) water, a water-miscible polar solvent that is completely miscible with water, has a boiling point of less than 100 ° C, and a vapor pressure at 25 ° C of 10 kPa or more, and dissolves in water to 5 g / L or less preparing an ink by dissolving a polymer resin in a mixed solvent composed of a non-water-miscible non-polar solvent having a boiling point of greater than 100° C. and a vapor pressure of less than 10 kPa at 25° C.; b) forming a non-conductive structure by coating the ink on a copper foil and then drying the ink; c) electroplating the surface of the copper foil on which the non-conductive structure is formed; and d) manufacturing a porous copper three-dimensional current collector having a surface shape of a dimple structure by removing the non-conductive structure.

As such, the method for manufacturing a porous copper three-dimensional current collector according to the present invention can effectively manufacture a porous copper three-dimensional current collector having a uniform dimple structure surface structure through a simple method of surface treatment of copper foil with ink and then electrolytic copper plating, As a result, process automation and mass production are possible, which has the advantage of improving productivity.

Hereinafter, each step of the method for manufacturing a porous copper three-dimensional current collector according to an example of the present invention will be described in detail.

First, a) water, a water-miscible polar solvent that is completely miscible with water, has a boiling point of less than 100 ° C, and has a vapor pressure of 10 kPa or more at 25 ° C., and dissolves in water at 5 g / L or less and has a boiling point A step of preparing an ink may be performed by dissolving a polymer resin in a mixed solvent composed of a non-water miscible non-polar solvent having a vapor pressure of less than 10 kPa at 25 °C and higher than 100 °C.

In this way, by using a mixed solvent composed of water, a water-miscible polar solvent, and a water-miscible non-polar solvent, the polymer resin can be well dissolved, and after coating and drying on the copper foil, a non-conductive surface having a fine and uniform surface pattern structure can be formed.

In one example of the present invention, it is preferable to use a water-miscible polar solvent that is easily volatilized while being well soluble in water. Through this, when the ink is coated on the copper foil and then dried, the water-miscible polar solvent is well volatilized, and a non-conductive structure having a size of a micron level can be formed on the surface of the copper foil.

As a specific example, the water-miscible polar solvent is completely miscible with water, has a boiling point of less than 100 ° C, and may have a vapor pressure of 10 kPa or more at 25 ° C., and more preferably a boiling point of 40 to 80 ° C. , The vapor pressure at 25 ° C. may be 15 to 50 kPa, and more preferably, the boiling point may be 50 to 60 ° C., and the vapor pressure at 25 ° C. may be 25 to 40 kPa. A preferred water-miscible polar solvent that satisfies this may be acetone. By using this, it is possible to form a non-conductive structure having a more uniform fine pattern by volatilizing acetone at an appropriate rate at room temperature.

In one embodiment of the present invention, it is preferable to use the water-miscible, non-polar solvent that is not miscible with water, can dissolve the polymer resin well, and has low volatility. Through this, after coating the ink on the copper foil, when the water-miscible polar solvent is volatilized and removed, a non-conductive structure having a size of a micron level can be formed on the surface of the copper foil.

As a specific example, the non-water miscible non-polar solvent is soluble in water at 5 g/L or less, has a boiling point greater than 100°C, and may have a vapor pressure at 25°C of less than 10 kPa, and more preferably 3 g in water. /L or less, boiling point greater than 105 ° C, vapor pressure at 25 ° C may be less than 6 kPa, more preferably soluble in water at 0.1 to 1 g / L, boiling point 105 to 140 ° C, It may have a vapor pressure of 1 to 3.5 kPa at 25 ° C. In this case, the solubility in water may be based on a value measured at 20 ° C. A preferred water-miscible non-polar solvent that satisfies this may be toluene. By using this, polystyrene can be effectively dissolved, and a non-conductive structure having a uniform fine pattern can be formed.

In addition, the ratio of water, water-miscible polar solvent, and water-non-water-miscible non-polar solvent in the mixed solvent is particularly important in order to improve the solubility of the polymer resin and to have a more uniform and fine-sized pattern of the non-conductive structure. If the ratio of the non-polar solvent, which is miscible with water in the mixed solvent, is too low, the polymer resin is not completely dissolved, and the shape and size of the pattern may become irregular. Accordingly, a non-conductive structure having a desired micropattern may not be formed, and finally, it may be difficult to manufacture a porous copper three-dimensional current collector having a surface shape of a dimple structure.

As a preferred example, the weight ratio of water: water-miscible polar solvent: non-water-miscible non-polar solvent may be 1: 2 to 5: 0.5 to 1.5, more preferably the water: water-miscible polar solvent: non-water-miscible non-polar solvent. The weight ratio of may be 1: 3 to 4: 0.8 to 1.2. In this range, a non-conductive structure having a desired micropattern is effectively formed, so that a porous copper three-dimensional current collector having a surface shape of a dimple structure can be manufactured later.

On the other hand, in one example of the present invention, it is preferable to use a non-platable material that is not electrolytically plated because the polymer resin dissolves well in a non-water miscible non-polar solvent and does not conduct electricity, and as a specific example, polystyrene is used. During electrolytic copper plating, it is preferable to form a dimple structure having an average diameter of 10 to 300 μm. More specifically, the polystyrene may have a weight average molecular weight of 10,000 to 150,000 g/mol.

The polymer resin may be dissolved in 0.5 to 5% by weight of the total weight of the ink, more preferably 1 to 4% by weight, and more preferably 2 to 3% by weight. In this range, after the water-miscible polar solvent is volatilized, the remaining ink has an appropriate viscosity, so that a non-conductive structure having a desired micropattern can be effectively formed, and a dimple structure having an average diameter of 10 to 300 μm during electrolytic copper plating. can form

Next, b) coating the ink on the copper foil and then drying it to form a non-conductive structure may be performed.

As a more specific example, step b) may be characterized in that the (wet) coating is coated with a thickness of 300 μm or less. Through this, it is possible to form a non-conductive structure having a desired micropattern. More specifically, the (wet) coating thickness may be 0.1 to 300 μm, more preferably 0.3 to 200 μm, more preferably 0.5 to 100 μm, and particularly preferably 1 to 50 μm.

At this time, the method of coating the ink is not particularly limited as long as it is a method commonly used in the art, and specifically, for example, bar coating, spray coating, ultrasonic spray coating, comma coating, gravure coating, microgravure coating, slit die One or more methods selected from coating, roller coating, inkjet printing, pad printing, screen printing, rotary screen printing, gravure printing, gravure offset printing, reverse offset printing, flexographic printing, dispensing coating, and airgel deposition may be used.

Next, c) electrolytic copper plating of the surface of the copper foil on which the non-conductive structure is formed may be performed, and the electrolytic copper plating method may be performed according to a conventional method.

As a preferred example, CuSO ₄ 5H ₂ O 20 ~ 80 g / ℓ (based on Cu), sulfuric acid (H ₂ SO ₄ ) 120 ~ 140 g / ℓ, hydrochloric acid (HCl) 10 ~ 30 ppm and gelatin additives 1 ~ 5 After immersing the copper foil on which the non-conductive structure is formed in a copper plating bath containing ppm, electrolytic copper plating may be performed by applying a current of 1 to 10 A for 1 to 10 minutes, preferably a current of 3 to 6 A Electrolytic copper plating may be performed by applying for 2 to 5 minutes. By performing the electrolytic copper plating within this range, it is possible to manufacture a porous copper three-dimensional current collector having a surface shape of a desired dimple structure and having a tensile strength of 20 kgf/mm 2 or more.

Thereafter, d) manufacturing a porous copper three-dimensional current collector having a surface shape of a dimple structure by removing the non-conductive structure may be performed.

The non-conductive structure may be removed using a solvent. At this time, the solvent may be used without particular limitation as long as it can be removed by dissolving the previously used polymer resin. Specifically, for example, the solvent may be any one or two or more selected from the group consisting of alcohol-based solvents such as methanol, ethanol, and isopropanol, and aromatic hydrocarbon-based solvents such as toluene and xylene, but are not necessarily limited thereto. .

In addition, another aspect of the present invention relates to a porous copper three-dimensional current collector prepared from the method of manufacturing a porous copper three-dimensional current collector described above, and in detail, to a porous copper three-dimensional current collector having a surface shape of a dimple structure it's about

As described in the manufacturing method above, the porous copper three-dimensional current collector having a dimple structure surface shape manufactured through the above manufacturing method increases the contact area and binding force between the current collector and the active material, thereby minimizing resistance at the interface, , it can overcome the problems of long lithium ion diffusion distance and low electron transfer that affect fast charging performance.

More specifically, in the porous copper three-dimensional current collector according to one embodiment of the present invention, the average diameter of the dimples may be 10 to 300 μm, which may be controlled by a coating method.

In addition, the tensile strength of the porous copper three-dimensional current collector may be 20 kgf/mm 2 or more, more specifically 20 to 50 kgf/mm 2 , and more specifically 25 to 35 kgf/mm 2 . Furthermore, the surface roughness (Rz) of the porous copper three-dimensional current collector may be 4 μm or less, more preferably 3 μm or less, and even more preferably 2 μm or less, and the elongation is 3% or more, more preferably 4% or more, still more may be 5% or more, and the specific surface area increase rate compared to the flat current collector (copper foil base material that has not been treated) may be 5% or more, more preferably 10% or more, and even more preferably 15% or more. Within this range, the secondary battery When used as an anode current collector for a battery, better battery performance can be realized. In this case, the lower limit of the surface roughness may be greater than 0, the upper limit of the elongation rate may be 10%, and the upper limit of the specific surface area increase rate may be 30%.

Hereinafter, a porous copper three-dimensional current collector and a manufacturing method thereof according to the present invention will be described in more detail through examples. However, the following examples are only one reference for explaining the present invention in detail, but the present invention is not limited thereto, and may be implemented in various forms.

Also, unless defined otherwise, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description herein is merely to effectively describe specific embodiments and is not intended to limit the present invention. In addition, the unit of additives not specifically described in the specification may be % by weight.

[Example 1]

After immersing the copper foil in a solution of 40 parts by weight of Ace Clean (base degreaser/OKUNO chemical) dissolved in 1000 parts by weight of water, degreased at 50°C for 2 minutes, washed with water, and then 75 parts by weight of top acid (acid degreaser/OKUNO chemical) 1000 parts by weight of water. Copper foil was prepared by washing with a solution dissolved in parts by weight for 1 minute at room temperature, washing with water, and drying water at 60 ° C.

Separately, a mixed solvent was prepared by mixing 550 parts by weight of acetone and 100 parts by weight of toluene with respect to 100 parts by weight of water, and then 30 parts by weight of polystyrene (weight average molecular weight 31,200 g/mol (n = 300)) was dissolved in the mixed solvent. A non-conductive ink was prepared.

The non-conductive ink was bar-coated on the pretreated copper foil to have a wet coating thickness of 16 μm, and then dried in an oven at 80° C. for 20 minutes to form a non-conductive structure.

Next, the non-conductive structure is placed in a copper plating bath containing 50 g/ℓ of CuSO ₄ 5H ₂ O (based on Cu), 130 g/ℓ of sulfuric acid (H ₂ SO ₄ ), 20 ppm of hydrochloric acid (HCl), and 3 ppm of gelatin. After immersing the formed copper foil, electrolytic copper plating was performed by applying a current of 4 A for 3 minutes, followed by washing with water and drying.

Finally, a porous copper three-dimensional current collector having a surface shape of a dimple structure was prepared by dissolving and removing the non-conductive structure with toluene and ethanol.

[Examples 2 to 12]

All processes were performed in the same manner as in Example 1 except that the amount of the mixed solvent and the polystyrene resin was changed as shown in Table 1 below.

[Comparative Example 1]

After immersing the copper foil in a solution of 40 parts by weight of Ace Clean (base degreaser/OKUNO chemical) dissolved in 1000 parts by weight of water, degreased at 50°C for 2 minutes, washed with water, and then 75 parts by weight of top acid (acid degreaser/OKUNO chemical) 1000 parts by weight of water. Copper foil was prepared by washing with a solution dissolved in parts by weight for 1 minute at room temperature, washing with water, and drying water at 60 ° C.

[Comparative Example 2]

All processes were performed in the same manner as in Example 1 except that ethanol (vapor pressure 7.9 kPa at 25 ° C.) was used as a water-miscible polar solvent.

[Comparative Example 3]

All processes were performed in the same manner as in Example 1 except that chloroform (water solubility: 8.09 g/L at 20 °C, vapor pressure: 25.9 kPa at 25 °C) was used as the non-water miscible, non-polar solvent.

parts by weight water water miscible polar solvent Non-water miscible non-polar solvent polystyrene acetone ethanol toluene chloroform Example 1 100 550 - 100 - 30 Example 2 100 550 - 100 - 55 Example 3 100 550 - 100 - 78 Example 4 120 550 - 100 - 78 Example 5 154 550 - 100 - 78 Example 6 165 550 - 100 - 78 Example 7 100 100 - 100 - 78 Example 8 100 350 - 100 - 78 Example 9 100 670 - 100 - 78 Example 10 100 670 - 30 - 78 Example 11 100 670 - 53 - 78 Example 12 100 670 - 89 - 78 Comparative Example 1 - - - - - - Comparative Example 2 100 - 550 - 100 78 Comparative Example 3 100 - 550 - 100 78

[Attribute evaluation]

1) Dimple structure analysis: The presence or absence of the dimple structure was confirmed through a scanning electron microscope (SEM), and the average diameter was randomly measured by measuring the diameters of 20 dimples in the SEM image, and the average values are shown in Table 2 below.

2) Tensile strength: When a tensile test was performed on the manufactured porous copper three-dimensional current collector (thickness: 0.015 mm, width: 15 mm) using a universal testing machine (UTM) under conditions of a speed of 50 mm/min and a gauge length of 61.94 mm Tensile strength (kgf/mm2) was measured, and the results are shown in Table 2 below.

parts by weight dimple structure
presence or absence of formation dimple mean diameter
(μm) tensile strength
(kgf/㎟) Example 1 ○ 32.3 26.2 Example 2 ○ 35.8 26.4 Example 3 ○ 44.5 27.6 Example 4 ○ 67.3 26.3 Example 5 ○ 84.7 28.1 Example 6 ○ 120.3 27.5 Example 7 ○ 134.8 26.2 Example 8 ○ 156.3 26.7 Example 9 ○ 189.7 27.3 Example 10 ○ 211.2 26.4 Example 11 ○ 245.6 25.9 Example 12 ○ 280.3 26.7 Comparative Example 1 X - 25.9 Comparative Example 2 X - 26.0 Comparative Example 3 X - 26.1

Referring to Tables 1 and 2, when water, acetone, and toluene were mixed in appropriate ratios, a copper current collector having a dimple structure surface shape could be manufactured, and the dimple size could be adjusted by adjusting the ratio of the mixed solvent And it was found.

On the other hand, when the content of the polymer resin is small compared to the mixed solvent or the mixing amount of toluene is too small compared to acetone, the dimple structure is not properly formed.

3) Secondary battery fast charging performance evaluation:

The copper current collectors of Example 3 and Comparative Example 1 were used as the negative current collector, respectively, and a negative electrode was formed by mixing 97% by weight of artificial graphite and 3% by weight of a binder on the copper current collector to improve the fast charging performance of the secondary battery. evaluated.

As confirmed in FIG. 5, in the case of using a porous copper three-dimensional current collector (test sample) having a surface shape of a dimple structure of Example 3 compared to the copper current collector of Comparative Example 1, which is an existing flat copper foil (REF), The C-rate characteristics were more excellent, and in particular, it was confirmed that the C-rate characteristics were improved by about 10% or more at 0.5 C or higher.

Although the present invention has been described through specific details and limited examples as described above, this is only provided to help a more general understanding of the present invention, the present invention is not limited to the above examples, and the present invention belongs Various modifications and variations from these descriptions are possible to those skilled in the art.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and it will be said that not only the claims to be described later, but also all modifications equivalent or equivalent to these claims belong to the scope of the present invention. .

Claims (12)

a) water, water-miscible polar solvents miscible with water, boiling point less than 100°C, vapor pressure at 25°C greater than 10 kPa, and water-soluble at less than 5 g/L, boiling point greater than 100°C preparing an ink by dissolving a polymer resin in a mixed solvent composed of a water-non-miscible non-polar solvent having a vapor pressure of less than 10 kPa at 25° C.;
b) forming a non-conductive structure by coating the ink on a copper foil and then drying the ink;
c) electroplating the surface of the copper foil on which the non-conductive structure is formed; and
d) manufacturing a porous copper three-dimensional current collector having a surface shape of a dimple structure by removing the non-conductive structure;
A method for producing a porous copper three-dimensional current collector comprising a. According to claim 1,
The water-miscible polar solvent is acetone, and the water-miscible non-polar solvent is toluene. According to claim 1,
The weight ratio of the water: water-miscible polar solvent: non-water-miscible non-polar solvent is 1: 2 to 5: 0.5 to 1.5, a method for producing a porous copper three-dimensional current collector. According to claim 1,
The polymer resin is dissolved in 0.5 to 5% by weight of the total weight of the ink, a method for producing a porous copper three-dimensional current collector. According to claim 1,
The step b) is a method for manufacturing a porous copper three-dimensional current collector, characterized in that the coating is coated with a Ÿ‡ (wet) coating thickness of 300 μm or less. A porous copper three-dimensional current collector manufactured according to the manufacturing method of claim 1 and having a surface shape of a dimple structure. According to claim 6,
The average diameter of the dimples is 10 to 300 ㎛, the porous copper three-dimensional current collector. According to claim 6,
The tensile strength of the porous copper three-dimensional current collector is 20 kgf / ㎟ or more, the porous copper three-dimensional current collector. According to claim 6,
The surface roughness (Rz) of the porous copper three-dimensional current collector is 4 μm or less, the porous copper three-dimensional current collector. According to claim 6,
The elongation of the porous copper three-dimensional current collector is 3% or more, the porous copper three-dimensional current collector. According to claim 6,
The porous copper three-dimensional current collector has a specific surface area increase rate of 5% or more compared to the flat copper current collector. A secondary battery comprising the porous copper three-dimensional current collector of claim 6.

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