A metal foil, a porous copper foil, a method for manufacturing the same, and a lithium ion battery using the same

Abstract

This invention relates to a metal foil, a porous copper foil, a method for preparing the same, and a lithium-ion battery using the material. This method allows for the preparation of relatively thin metal foils, including copper foil, through a simple, low-cost, and easily industrially scalable approach. Furthermore, the pore size and thickness of the porous copper foil can be controlled based on the screen printing pattern, the height difference between the screen printing plate and the titanium plate, and the electrolysis time. This effectively solves the problems of complex pore size control and excessively thick foils in current metal foil, especially porous copper foil, preparation methods.

Description

Technical Field

[0001] This invention relates to the field of new energy batteries, and in particular to a metal foil, a porous copper foil, a method for preparing the same, and a lithium-ion battery using the same material. Background Technology

[0002] With the booming development of the new energy industry, people have increasingly higher requirements for devices such as power batteries, 3C digital batteries, and large-scale energy storage power supplies. Higher energy density, good fast-charging performance, higher safety, and lower cost are the future development directions for energy storage devices. Electrolytic copper foil, as the most commonly used negative electrode current collector in lithium-ion batteries, mainly plays the role of loading the negative electrode active material and collecting charge. To further improve the energy density of lithium-ion batteries, electrolytic copper foil is currently mainly developing towards thinner and lighter designs. Currently, the thinnest lithium-ion battery copper foil that can be mass-produced is 4μm, but its yield is low and its production cost is high.

[0003] Compared to traditional dual-sided lithium-ion battery copper foil, porous copper foil has a unique hollow structure, making it significantly lighter per unit area (including pore area) for the same thickness – a substantial advantage. The larger surface area of ​​porous copper foil, when used as a current collector in the negative electrode of lithium-ion batteries, allows for a significant increase in the coating amount of the negative electrode active material. The unique hollow structure of porous copper foil also makes it easier for the double-sided coated electrode material to be wetted by the electrolyte. During battery charging and discharging, the transport path of lithium ions in the electrolyte is reduced, enabling faster ion insertion / extraction in the negative electrode material. This improves the fast-charging performance of lithium-ion batteries and extends their lifespan.

[0004] Currently, there are many reported methods for preparing porous copper foil, including hydrogen bubble template method, dealloying method, powder sintering method, and organic template method. Porous copper foil prepared by these methods suffers from defects such as loose structure, low mechanical strength, difficulty in controlling pore size, and relatively thick foil. Furthermore, these methods are costly to produce porous copper foil but pose significant environmental pollution risks.

[0005] Therefore, it is of great significance to invent a convenient and low-cost method for preparing porous copper foil. Summary of the Invention

[0006] In view of the above problems, this application provides a metal foil, including a porous copper foil, a preparation method, and a lithium-ion battery using the material. This method can prepare thin metal foils, including copper foils, through a simple, low-cost, and easily industrialized approach. Furthermore, the pore size and thickness of the porous copper foil can be controlled according to the screen pattern, the height difference between the screen printing plate and the titanium plate, and the electrolysis time. This effectively solves the problems of complex pore size control and thick foils in current metal foil, especially porous copper foil, preparation methods. S1: An insulating coating is screen printed onto a titanium plate with a titanium content ≥99.8% to obtain an electrodeposition template containing an insulating array.

[0007] S2: The electrodeposition template is placed in an electrolytic cell as the cathode and a tantalum-titanium plate is placed as the anode. An electrolyte containing metal ions is added to the electrodeposition template to perform electrodeposition, thereby obtaining an electrodeposition composite. The electrodeposition composite includes the electrodeposition template and the deposited metal attached to the electrodeposition template. The deposited metal is peeled off from the electrodeposition template to obtain the metal foil.

[0008] Unlike existing technologies, this technical solution obtains metal foils with controllable thickness and patterns through screen printing and electrodeposition. By screen printing, an insulating array pattern is designed, and the hollow pattern on the metal foil can be refined. The metal foil is prepared by electrochemical deposition using an electrodeposition template containing an insulating array as a substrate. During electrolysis, metal ions are deposited in the non-insulating areas to obtain a one-piece metal foil with controllable structure, uniformity, and high mechanical strength.

[0009] Furthermore, a method for preparing porous copper foil is also provided, comprising the following steps:

[0010] S11: The insulating coating is screen-printed onto a titanium plate with a titanium content ≥99.8% to obtain an insulating array template;

[0011] S21: Place the electrodeposition template as the cathode and the tantalum-titanium plate as the anode in an electrolytic cell, and add Cu. 2+ Electrodeposition is performed on the electrodeposition template using an electrolyte with a concentration of 80-100 g / L to obtain an electrodeposition composite; the electrodeposition composite includes the electrodeposition template and deposited copper attached to the electrodeposition template; the deposited copper is peeled off the electrodeposition template to obtain the porous copper foil.

[0012] Unlike existing technologies, this technical solution obtains porous copper foil through screen printing and electrodeposition. The screen printing method refines the insulating array pattern, allowing the copper foil to have uniform pores. The porous copper foil is prepared by electrochemical deposition using an electrodeposition template containing an insulating array as a substrate. During electrodeposition, copper ions are deposited in the non-insulating areas to obtain a one-piece porous copper foil with controllable pore structure, uniform pores, and high mechanical strength.

[0013] Furthermore, in step S11, the surface roughness Rz of the titanium plate is 0.5-3 μm.

[0014] Furthermore, in step S11, the insulating coating includes one or more of polyacrylic coating, epoxy coating, insulating ink, and PRTV composite coating.

[0015] Furthermore, in step S11, the screen printing stencil is 50-500 mesh, and the height difference between the screen printing stencil and the titanium plate is 1-4 mm.

[0016] Furthermore, in step S21, the concentration of H2SO4 in the electrolyte is 100-130 g / L.

[0017] Furthermore, in step S21, the electrolyte also includes 5-40 mg / L of leveling agent, 1-20 mg / L of brightener, 5-30 mg / L of leveling agent and 5-35 mg / L of chloride ions.

[0018] Furthermore, in step S21, during the electrodeposition process, the electrolyte temperature is 40-60℃ and the current density is 10-100 A / dm³. 2 .

[0019] The second aspect of this application provides a porous copper foil, which is prepared using the preparation method described in the first aspect of this application.

[0020] Unlike existing technologies, the porous copper foil prepared by this method has a larger surface area. Using it as a current collector in the negative electrode of a lithium-ion battery significantly increases the coating amount of the negative electrode active material. The unique hollow structure of the porous copper foil makes it easier for the double-sided coated electrode material to be wetted by the electrolyte. During battery charging and discharging, the transport path of lithium ions in the electrolyte is reduced, allowing for faster ion insertion / extraction in the negative electrode material. This improves the fast-charging performance of lithium-ion batteries and extends their lifespan.

[0021] Furthermore, the thickness of the porous copper foil is 4-100 μm. The thickness of the copper foil can be controlled by the electrolysis time.

[0022] A third aspect of this application provides a lithium-ion battery, wherein the lithium-ion battery uses the porous copper foil described in Part II of this application as the negative electrode current collector.

[0023] The above description of the invention is merely an overview of the technical solution of this application. In order to enable those skilled in the art to better understand the technical solution of this application and to implement it based on the textual description, and to make the above-mentioned objectives and other objectives, features and advantages of this application easier to understand, the following description is provided in conjunction with the specific embodiments and accompanying drawings of this application. Attached Figure Description

[0024] The accompanying drawings are only used to illustrate the principles, implementation methods, applications, features, and effects of specific embodiments of this application and other related content, and should not be considered as limitations on this application.

[0025] In the accompanying drawings of the instruction manual:

[0026] Figure 1 A schematic diagram of the process for preparing porous copper foil;

[0027] Figure 2 This is a photograph of the deposition template under an optical microscope in Example 1;

[0028] Figure 3 This is an optical microscope image of the porous copper foil prepared in Example 1. Detailed Implementation

[0029] To illustrate the possible application scenarios, technical principles, implementable specific solutions, and achievable objectives and effects of this application in detail, the following description, in conjunction with the listed specific embodiments and accompanying drawings, provides a detailed explanation. The embodiments described herein are merely illustrative of the technical solutions of this application and are therefore intended to limit the scope of protection of this application.

[0030] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0031] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0032] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.

[0033] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order relationship between these entities or operations.

[0034] Unless otherwise specified, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a list of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.

[0035] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.

[0036] The first aspect of this application provides a method for preparing a metal foil, comprising the following steps:

[0037] S1: The insulating coating is screen-printed onto a titanium plate with a titanium content ≥99.8% to obtain an electrodeposition template containing an insulating array;

[0038] S2: The electrodeposition template is placed in an electrolytic cell as the cathode and a tantalum-titanium plate is placed as the anode. An electrolyte containing metal ions is added to the electrodeposition template to perform electrodeposition, thereby obtaining an electrodeposition composite. The electrodeposition composite includes the electrodeposition template and the deposited metal attached to the electrodeposition template. The deposited metal is peeled off from the electrodeposition template to obtain the metal foil.

[0039] Unlike existing technologies, this technical solution obtains metal foils with controllable thickness and patterns through screen printing and electrodeposition. By screen printing, an insulating array pattern is designed, and the hollow pattern on the metal foil can be refined. The metal foil is prepared by electrochemical deposition using an electrodeposition template containing an insulating array as a substrate. During electrolysis, metal ions are deposited in the non-insulating areas to obtain a one-piece metal foil with controllable structure, uniformity, and high mechanical strength.

[0040] Furthermore, a method for preparing porous copper foil is also provided, comprising the following steps:

[0041] S11: The insulating coating is screen-printed onto a titanium plate with a titanium content ≥99.8% to obtain an insulating array template;

[0042] S21: Place the electrodeposition template as the cathode and the tantalum-titanium plate as the anode in an electrolytic cell, and add Cu. 2+ Electrodeposition is performed on the electrodeposition template using an electrolyte with a concentration of 80-100 g / L to obtain an electrodeposition composite; the electrodeposition composite includes the electrodeposition template and deposited copper attached to the electrodeposition template; the deposited copper is peeled off the electrodeposition template to obtain the porous copper foil.

[0043] Unlike existing technologies, this technical solution obtains porous copper foil through screen printing and electrodeposition. The screen printing method refines the insulating array pattern, allowing the copper foil to have uniform pores. The porous copper foil is prepared by electrochemical deposition using an electrodeposition template containing an insulating array as a substrate. During electrodeposition, copper ions are deposited in the non-insulating areas to obtain a one-piece porous copper foil with controllable pore structure, uniform pores, and high mechanical strength.

[0044] Furthermore, in step S11, the surface roughness Rz of the titanium plate is 0.5-3 μm.

[0045] Furthermore, in step S11, the insulating coating includes one or more of polyacrylic coating, epoxy coating, insulating ink, and PRTV composite coating.

[0046] Furthermore, the insulating ink contains insulating fillers such as PP and PE.

[0047] Furthermore, in step S11, the screen printing stencil is 50-500 mesh, and the height difference between the screen printing stencil and the titanium plate is 1-4 mm.

[0048] Furthermore, in step S21, the concentration of H2SO4 in the electrolyte is 100-130 g / L.

[0049] Furthermore, in step S21, the electrolyte also includes 5-40 mg / L of leveling agent, 1-20 mg / L of brightener, 5-30 mg / L of leveling agent and 5-35 mg / L of chloride ions.

[0050] The positioning agents include, but are not limited to, collagen, gelatin, and hydroxyethyl cellulose.

[0051] The brighteners include, but are not limited to, sodium polydithiopropane sulfonate, sodium 3-mercapto-1-propanesulfonate, and thiourea.

[0052] The leveling agent includes, but is not limited to, polyethylene glycol and phenylethylamine.

[0053] The chloride ions include, but are not limited to, hydrochloric acid and copper chloride.

[0054] Furthermore, in step S21, during the electrodeposition process, the electrolyte temperature is 40-60℃ and the current density is 10-100 A / dm³. 2 .

[0055] The second aspect of this application provides a porous copper foil, which is prepared using the preparation method described in the first aspect of this application.

[0056] Unlike existing technologies, the porous copper foil prepared by this method has a larger surface area. Using it as a current collector in the negative electrode of a lithium-ion battery significantly increases the coating amount of the negative electrode active material. The unique hollow structure of the porous copper foil makes it easier for the double-sided coated electrode material to be wetted by the electrolyte. During battery charging and discharging, the transport path of lithium ions in the electrolyte is reduced, allowing for faster ion insertion / extraction in the negative electrode material. This improves the fast-charging performance of lithium-ion batteries and extends their lifespan.

[0057] Furthermore, the thickness of the porous copper foil is 4-100 μm. The thickness of the copper foil can be controlled by the electrolysis time.

[0058] A third aspect of this application provides a lithium-ion battery, wherein the lithium-ion battery uses the porous copper foil described in Part II of this application as the negative electrode current collector.

[0059] The titanium plate in this embodiment is a TA1 titanium plate with a titanium content ≥99.8%, Fe<0.06, O<0.06, C<0.02, and N<0.02.

[0060] Example 1:

[0061] 1. Use sandpaper to polish the titanium plate until Rz = 0.5-3μm. After polishing, clean the titanium plate with anhydrous ethanol and pure water.

[0062] 2. Place the titanium plate on a horizontal platform. Position the screen printing stencil (300 mesh) 2mm above the titanium plate. Add the insulating coating (polyacrylic coating) to the stencil. First, spread the insulating coating evenly on the surface of the screen, and then use a scraper to spread the insulating coating onto the surface of the titanium plate.

[0063] 3. The titanium plate coated with the insulating array is air-dried naturally to obtain an electrodeposition template containing the insulating array.

[0064] 4. Configure Cu 2+ An electrolyte with a concentration of 90 g / L, H2SO4 concentration of 120 g / L, chloride ion concentration of 20 mg / L, sodium polydisulfide dipropane sulfonate concentration of 3 mg / L, collagen concentration of 15 mg / L, and polyethylene glycol concentration of 20 mg / L.

[0065] 5. Stir the electrolyte in the electrolytic cell until homogeneous and heat it to 50±2℃.

[0066] 6. Place the electrodeposition template containing the insulating array and the tantalum-titanium plate into the electrolytic cell. Use the electrodeposition template containing the insulating array as the cathode and the tantalum-titanium plate as the anode for electrodeposition. The current density is 10-100 A / dm³. 2 .

[0067] 7. Prepare a porous copper foil with a thickness of 8 μm by adjusting the electrodeposition time according to the current density. After electrodeposition, peel the porous copper foil off the surface of the titanium plate with the insulating array.

[0068] Example 2

[0069] The difference from Example 1 is that the screen printing stencil is 100 mesh, and the height difference between the screen printing stencil and the titanium plate is 1 mm. All other parameters are the same as in Example 1.

[0070] Example 3

[0071] The difference from Example 1 is that the screen printing stencil is 200 mesh, and the height difference between the screen printing stencil and the titanium plate is 2 mm. All other parameters are the same as in Example 1.

[0072] Example 4

[0073] The difference from Example 1 is that the additives in the electrolyte and their concentrations are: chloride ions (20 mg / L), thiourea (5 mg / L), hydroxyethyl cellulose (15 mg / L), and polyethylene glycol (20 mg / L). All other parameters are the same as in Example 1.

[0074] Example 5

[0075] The difference from Example 1 is that the additives in the electrolyte and their concentrations are: chloride ions (10 mg / L), sodium 3-mercapto-1-propanesulfonate and thiourea (8 mg / L), gelatin (10 mg / L), and Janus Green (15 mg / L). All other parameters are the same as in Example 1.

[0076] Example 6

[0077] The difference from Example 1 is that the additives in the electrolyte and their concentrations are: chloride ions (10 mg / L), sodium 3-mercapto-1-propanesulfonate and thiourea (8 mg / L), gelatin (20 mg / L), and polyethylene glycol (25 mg / L). All other parameters are the same as in Example 1.

[0078] Example 7

[0079] The difference from Example 1 is that the height difference between the screen printing plate and the titanium plate is 1 mm. All other parameters are the same as in Example 1.

[0080] Example 8

[0081] The difference from Example 2 is that a 200-mesh screen printing plate is used, while all other parameters remain the same as in Example 2.

[0082] Example 9

[0083] The difference from Example 1 is that the sodium polydisulfide dipropane sulfonate in the electrolyte is replaced with thiourea, while all other parameters remain the same as in Example 1.

[0084] The basic physical properties of the porous copper foils prepared in each embodiment are shown in Table 1.

[0085] Table 1 Performance Test Table

[0086] Example Tensile strength (MPa) Elongation (%) Warp (mm) Pore ​​diameter (μm) Example 1 393.5 12.6 6 52 Example 2 362.5 13.2 5 143 Example 3 345.2 14.8 6 72 Example 4 288.6 8.9 10 52 Example 5 362.7 12.6 7 54 Example 6 329.1 13.9 6 54 Example 7 371.2 14.2 7 47 Example 8 378.8 13.7 6 68 Example 9 306.9 9.6 14 53

[0087] The tensile strength and elongation of the porous copper foil were tested according to IPC-TM-6502.4.18.1A, the warpage was measured according to IPC-TM-6502.4.22, and the pore diameter was tested according to the method in GB / T 13453.1-2012.

[0088] As can be seen from the test results in Table 1, the preparation method provided by the present invention can produce porous copper foil with uniform distribution, consistent pore size, and high mechanical strength, thus solving the problems mentioned in the technical background, such as loose structure, low mechanical strength, difficulty in controlling pore size, and thick foil material.

[0089] This embodiment prepares porous copper foil using the same method. This method can also be applied to prepare porous nickel, porous zinc, and other foils. The preparation method of the electrodeposition template containing the insulating array is the same as that in this embodiment, but the electrolyte system is different.

[0090] Finally, it should be noted that although the above embodiments have been described in the text and drawings of this application, this should not limit the scope of patent protection of this application. Any technical solutions that are based on the essential concept of this application and utilize the content described in the text and drawings of this application, resulting in equivalent structural or procedural substitutions or modifications, as well as the direct or indirect application of the technical solutions of the above embodiments to other related technical fields, are all included within the scope of patent protection of this application.

Claims

1. A method for preparing a metal foil, characterized in that, Includes the following steps: S1: The insulating coating is screen-printed onto a titanium plate with a titanium content ≥99.8% to obtain an electrodeposition template containing an insulating array; S2: The electrodeposition template is placed in an electrolytic cell as the cathode and a tantalum-titanium plate is placed as the anode. An electrolyte containing metal ions is added to the electrodeposition template to perform electrodeposition, thereby obtaining an electrodeposition composite. The electrodeposition composite includes the electrodeposition template and the deposited metal attached to the electrodeposition template. The deposited metal is peeled off from the electrodeposition template to obtain the metal foil.

2. A method for preparing porous copper foil, characterized in that, Includes the following steps: S11: The insulating coating is screen-printed onto a titanium plate with a titanium content ≥99.8% to obtain an insulating array template; S21: Place the electrodeposition template as the cathode and the tantalum-titanium plate as the anode in an electrolytic cell, and add Cu. 2+ Electrodeposition is performed on the electrodeposition template using an electrolyte with a concentration of 80-100 g / L to obtain an electrodeposition composite; the electrodeposition composite includes the electrodeposition template and deposited copper attached to the electrodeposition template; the deposited copper is peeled off the electrodeposition template to obtain the porous copper foil.

3. The preparation method according to claim 2, characterized in that, In step S11, the surface roughness Rz of the titanium plate is 0.5-3 μm.

4. The preparation method according to claim 2, characterized in that, In step S11, the insulating coating includes one or more of polyacrylic coating, epoxy coating, insulating ink, and PRTV composite coating.

5. The preparation method according to claim 2, characterized in that, In step S11, the screen printing stencil is 50-500 mesh, and the height difference between the screen printing stencil and the titanium plate is 1-4 mm.

6. The preparation method according to claim 2, characterized in that, In step S21, the concentration of H2SO4 in the electrolyte is 100-130 g / L; the electrolyte also includes 5-40 mg / L of leveling agent, 1-20 mg / L of brightener, 5-30 mg / L of leveling agent and 5-35 mg / L of chloride ions.

7. The preparation method according to claim 2, characterized in that, In step S21, during electrodeposition, the electrolyte temperature is 40-60℃ and the current density is 10-100 A / dm³. 2 .

8. A porous copper foil, characterized in that, The porous copper foil is prepared using any one of the preparation methods described in claims 2-7.

9. The porous copper foil according to claim 8, characterized in that, The thickness of the porous copper foil is 4-100 μm.

10. A lithium-ion battery, characterized in that, The lithium-ion battery uses the porous copper foil described in claim 8 or 9 as the negative electrode current collector.

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