Electrolytic cathode and method for its production, porous current collector production device

Abstract

The application provides an electrolytic cathode and a preparation method thereof, and a porous current collector preparation device. The preparation method of the electrolytic cathode comprises the following steps: forming a mask layer with a patterned area on the surface of an electrode base; etching the electrode base with the mask layer to form etching holes at positions corresponding to the patterned area of the electrode base; filling the etching holes with insulating material; and removing the mask layer to obtain the electrolytic cathode. The preparation method of the electrolytic cathode is not prone to damage the insulating area on the surface of the electrolytic cathode, and the surface quality of the electrolytic cathode is good, which is beneficial to improving the production efficiency and quality of the porous current collector.

Description

Technical Field

[0001] This application relates to the field of battery manufacturing technology, and in particular to an electrolytic cathode and its preparation method, and a porous current collector preparation device. Background Technology

[0002] In recent years, as the application scope of secondary batteries has become increasingly wide, they have been widely used in energy storage power systems such as hydropower, thermal power, wind power and solar power plants, as well as in many fields such as power tools, electric bicycles, electric motorcycles and electric vehicles.

[0003] Using porous current collectors in the electrodes of secondary batteries is beneficial for increasing the specific surface area of ​​the current collector, mitigating the volume expansion effect caused by the embedding of active materials on the electrode, and improving the interfacial bonding between the active material and the current collector, thereby improving the cycle performance of the battery. Currently, the main methods for preparing porous current collectors include template methods (such as sol-gel methods, laser etching methods, deposition methods, etc.) and dealloying methods. Among these, electrolytic deposition is currently the most commonly used process for preparing porous current collectors, and the electrolytic cathode is the key component in the preparation of porous current collectors using electrolytic deposition. An insulating region needs to be formed on the surface of the electrolytic cathode. When depositing the current collector foil on the surface of the electrolytic cathode, the insulating region on the surface of the electrolytic cathode enables the current collector to form a porous structure.

[0004] However, due to the gradual oxidation of the electrolytic cathode surface during use, the gloss of the porous current collector prepared by the electrolytic deposition method decreases and the roughness increases. Therefore, the surface of the electrolytic cathode needs to be polished regularly. However, polishing can easily damage the insulating area on the surface of the electrolytic cathode prepared by traditional methods. In addition, traditional methods can easily cause oxidation of the electrode surface during the preparation of the electrolytic cathode, affecting the quality of the electrode surface and thus affecting the quality of the produced porous current collector.

[0005] Therefore, traditional electrolytic cathode preparation technology still needs further improvement. Summary of the Invention

[0006] This application is made in view of the above-mentioned problems, and one of its objectives is to provide an electrolytic cathode and its preparation method, as well as a porous current collector preparation device, wherein the insulating region on the surface of the electrolytic cathode prepared by the method is not easily damaged and the surface quality of the electrolytic cathode is good.

[0007] To achieve the above objectives, the first aspect of this application provides a method for preparing an electrolytic cathode, comprising the following steps:

[0008] A mask layer with patterned regions is formed on the surface of the electrode substrate;

[0009] The electrode substrate on which the mask layer is formed is etched to form etch holes at the positions of the electrode substrate corresponding to the patterned area;

[0010] The etched holes are filled with insulating material;

[0011] Remove the mask layer to obtain the electrolytic cathode.

[0012] The above-described method for fabricating an electrolytic cathode involves first forming a mask layer with patterned regions on the surface of an electrode substrate; then etching the electrode substrate to form etched holes corresponding to the patterned regions; filling the etched holes with insulating material and then removing the remaining mask layer. In this method, the insulating material is filled into the etched holes on the surface of the electrode substrate; after surface polishing of the electrolytic cathode, the insulating material in the etched holes is retained, eliminating the need to re-fabricate the insulating region on the electrode substrate surface after each polishing process.

[0013] Furthermore, filling the etched holes with insulating material can increase the contact area between the insulating material and the electrode substrate, improve the bonding force between the insulating material and the electrode substrate, and prevent the insulating material from being misaligned, which is beneficial to improving the uniformity of the pore distribution of the produced porous current collector.

[0014] Etching creates etched holes on the surface of the electrode substrate. Compared to mechanical drilling and laser drilling, wet etching has lower equipment requirements, is easier to process, and has lower costs. It is less likely to generate residual stress and burrs. Furthermore, the metal material on the electrode substrate surface does not melt or solidify during the process, and the processed surface is less prone to defects such as remelted layers and microcracks. This helps to give the electrolytic cathode a better surface quality, which in turn helps to improve the quality of the porous current collector produced.

[0015] In any embodiment, the etching includes one or more of electrochemical etching and chemical etching. Electrochemical or chemical etching processes can effectively form etched holes of a certain depth on the surface of the electrode substrate, facilitating the subsequent filling of the etched holes with insulating material.

[0016] In any embodiment, the electrochemical etching includes the following steps: using the electrode substrate as the anode to form an electrode pair with the cathode, etching the electrode substrate at the position corresponding to the patterned area in an electrochemical etching solution; the electrochemical etching solution includes a sodium chloride solution or a sodium bromide solution with a mass fraction of 0.1%~3%, and the current density of the electrochemical etching is 500 A / dm³. 2 ~10000A / dm 2The etching depth is 10μm~200μm. Using the above electrochemical etching method, etched holes of a predetermined depth can be formed on the electrode substrate at locations corresponding to the patterned areas.

[0017] In any embodiment, the power supply for the electrochemical etching is a pulsed power supply; optionally, the voltage of the pulsed power supply is 22V~28V, the pulse frequency is 500Hz~1000Hz, and the duty cycle is 30%~50%. This facilitates the full removal of the electrochemically etched products from the electrode substrate surface during pulse intervals, resulting in higher current density and smaller processing gaps, thereby effectively improving the concentrated material removal capability within the pulse width.

[0018] In any embodiment, the chemical etching includes the following steps: immersing the electrode substrate in a chemical etching solution and etching at a temperature of 50°C to 90°C for 0.5 to 3 hours. Through the above chemical etching process, etched holes can also be formed on the surface of the electrode substrate at locations corresponding to the patterned areas.

[0019] In any embodiment, the chemical etching solution includes one or more of nitric acid solution, hydrofluoric acid solution, sulfuric acid solution, hydrochloric acid solution, acetic acid solution, oxalic acid solution and tartaric acid solution.

[0020] In any embodiment, the electrode substrate is rotated during the etching process; optionally, the rotational speed of the electrode substrate is 0.5 m / min to 2 m / min. Thus, the rotation of the electrode substrate helps to remove reaction byproducts from the etched holes, which is beneficial for ensuring the etching rate.

[0021] In any embodiment, forming a mask layer with patterned regions on the surface of an electrode substrate includes the following steps: forming a mask layer on the surface of the electrode substrate; and sequentially performing patterned exposure and development on the mask layer. This allows for the convenient formation of a mask layer with patterned regions on the surface of the electrode substrate.

[0022] In any embodiment, the material of the mask layer includes one or more of photoresist and phenolic resin; the electrode substrate includes one or more of titanium, copper, iron, nickel and their corresponding alloys; the electrode substrate is roller-shaped; and the insulating material includes one or more of epoxy resin, vinyl resin, phenolic resin and polyketone resin.

[0023] In any embodiment, after removing the mask layer, the preparation method further includes a step of polishing the surface of the electrode substrate. By polishing the surface of the electrode substrate, excess insulating material can be removed, making the insulating material in the etched holes flush with the surface of the electrode substrate, thereby improving the surface quality of the electrolytic cathode.

[0024] In any embodiment, polishing the surface of the electrode substrate includes the following steps: polishing the electrode substrate with a 600-1000 mesh grinding wheel at a rotation speed of 1000 r / min to 1800 r / min. Thus, polishing removes excess insulating material from the surface of the electrode substrate.

[0025] The second aspect of this application provides an electrolytic cathode, prepared by the method for preparing the electrolytic cathode of the first aspect of this application. This electrolytic cathode does not require re-preparation of the insulating region after each polishing process; the bonding between the insulating material and the electrode substrate is good; and the surface quality of the electrolytic cathode is good. Using this electrolytic cathode is beneficial for improving the quality of the produced porous current collector.

[0026] A third aspect of this application provides a porous current collector preparation apparatus, including an electrolytic cell, a cathode, and an anode, wherein both the cathode and the anode are placed in the electrolytic cell, and the cathode is the electrolytic cathode of the second aspect of this application. Using this porous current collector preparation apparatus, porous current collectors with good pore distribution uniformity and good surface quality can be obtained.

[0027] In any embodiment, the electrolytic cell has arc-shaped sidewalls, the anode is arc-shaped and attached to the sidewalls, and the cathode is roller-shaped and rotatably placed in the arc-shaped groove of the anode. This rotation of the roller-shaped cathode within the arc-shaped groove of the anode allows for the simultaneous electrolytic deposition of a porous current collector on the cathode and the removal of the porous current collector from the cathode by a stripping roller, facilitating continuous operation and improving production efficiency.

[0028] Details of one or more embodiments of this application are set forth in the following drawings and description. Other features, objects, and advantages of this application will become apparent from the specification, drawings, and claims. Attached Figure Description

[0029] To better describe and illustrate the embodiments or examples provided in this application, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described embodiments or examples, or the best mode of conduct of these applications as currently understood. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0030] Figure 1 This is a process flow diagram of an embodiment of the electrolytic cathode preparation method of this application;

[0031] Figure 2 This is a cross-sectional schematic diagram of the electrolytic cathode preparation method according to an embodiment of this application after a mask layer is formed on the electrode substrate;

[0032] Figure 3 This is a schematic cross-sectional view of the mask layer after patterning in the electrolytic cathode preparation method according to an embodiment of this application;

[0033] Figure 4 This is a schematic cross-sectional view of the electrode substrate after etching in the electrolytic cathode preparation method according to an embodiment of this application.

[0034] Figure 5 This is a cross-sectional schematic diagram of the electrolytic cathode preparation method according to an embodiment of this application after filling the etched holes with insulating material;

[0035] Figure 6 This is a cross-sectional schematic diagram of the electrode substrate after polishing in the electrolytic cathode preparation method according to an embodiment of this application.

[0036] Figure 7 A schematic diagram of the structure of an electrolytic cathode according to an embodiment of this application;

[0037] Figure 8 A schematic diagram of the porous current collector preparation apparatus according to one embodiment of this application.

[0038] Explanation of reference numerals in the attached figures:

[0039] 10. Electrolytic cathode; 11. Electrode substrate; 12. Mask layer; 13. Insulating material; 111. Etched hole; 121. Patterned area; 100. Porous current collector preparation device; 101. Cathode; 102. Anode. Detailed Implementation

[0040] The following describes in detail, with appropriate reference to the accompanying drawings, the embodiments of the electrolytic cathode and its preparation method, and the porous current collector preparation apparatus of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0041] The "range" disclosed in this application can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints. Any endpoint can be independently included or excluded, and they can be combined arbitrarily; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are also listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0" and "5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥ 2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, when a parameter is described as an integer selected from "2~10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0042] In this application, the terms "multiple" or "various" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0043] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0044] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. The term "implementation" as used herein has a similar understanding.

[0045] Those skilled in the art will understand that the order in which the steps are written in the methods of various embodiments or examples does not imply a strict execution order and does not constitute any limitation on the implementation process. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0046] In this application, open-ended technical features or solutions described using terms such as "containing," "including," or "comprising" do not exclude additional members beyond those listed unless otherwise specified. They can be considered as providing both closed-ended features or solutions comprised of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, if A includes a1, a2, and a3, it may also include other members or exclude additional members unless otherwise specified. This can be considered as providing both the feature or solution that "A consists of a1, a2, and a3" and the feature or solution that "A includes not only a1, a2, and a3, but also other members." In this application, unless otherwise specified, A (e.g., B) indicates that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0047] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0048] Currently, electrolytic cathodes prepared by traditional methods are prone to damage to the insulating area on their surface during surface polishing, causing the insulating material to fall off. After each polishing, the insulating area needs to be re-prepared on the surface of the electrolytic cathode. In addition, traditional methods are prone to oxidation of the electrode surface during the preparation of electrolytic cathodes, affecting the quality of the electrode surface and thus affecting the quality of the porous current collector produced.

[0049] Based on this, please refer to Figure 1 One embodiment of this application provides a method for preparing an electrolytic cathode 10, the method comprising the following steps S100 to S400:

[0050] Step S100: A mask layer 12 with patterned regions 121 is formed on the surface of the electrode substrate 11;

[0051] Step S200: Etch the electrode substrate 11 on which the mask layer is formed to form an etch hole 111 at the position of the patterned area 121 on the electrode substrate 11;

[0052] Step S300: Fill the etched hole 111 with insulating material 13;

[0053] Step S400: Remove mask layer 12.

[0054] Traditional methods for preparing electrolytic cathodes for producing porous current collectors typically involve directly printing or spraying dot-shaped insulating material onto the surface of the electrode substrate. After curing, insulating bumps form on the surface of the electrode substrate. However, as the electrode substrate gradually oxidizes during use, forming an oxide layer, the surface gloss of the produced porous current collector decreases while its roughness increases. Therefore, the electrolytic cathode needs to be polished periodically. During polishing, the insulating bumps on the electrode substrate surface are damaged, requiring the re-fabrication of insulating bumps after each polishing. Furthermore, because the electrode substrate surface is relatively smooth, the adhesion between it and the insulating slurry is poor. Before curing, the insulating material is prone to fine flow on the electrode substrate surface, causing misalignment of the insulating material after curing and affecting the uniformity of the pore distribution in the produced porous current collector.

[0055] The method for preparing the electrolytic cathode 10 described above in this application first forms a mask layer 12 with a patterned region 121 on the surface of an electrode substrate 11; then the electrode substrate 11 is etched to form an etching hole 111 at the position corresponding to the patterned region 121 on the electrode substrate 11; after filling the etching hole 111 with insulating material 13, the remaining mask layer 12 is removed.

[0056] In the electrolytic cathode 10 prepared by this method, the insulating material 13 is filled in the etched holes 111 on the surface of the electrode substrate 11. After the electrolytic cathode 10 is surface polished, the insulating material 13 in the etched holes 111 can still be retained, eliminating the need to re-prepare the insulating area on the surface of the electrode substrate 11 after each polishing. Furthermore, by forming etched holes 111 on the surface of the electrode substrate 11 and filling the etched holes 111 with the insulating material 13, the contact area between the insulating material 13 and the electrode substrate 11 can be increased, improving the bonding force between the insulating material 13 and the electrode substrate 11. After polishing the electrode substrate 11, the insulating material 13 in the etched holes 111 will not experience positional deviation, which is beneficial for improving the pore distribution uniformity of the produced porous current collector.

[0057] In addition, traditional hole-forming methods include mechanical drilling and laser drilling. Mechanical drilling requires sophisticated equipment, is difficult to process, and can generate residual stress and burrs, affecting the surface quality of the electrolytic cathode 10, and has high production costs. Laser drilling is prone to melting, oxidation, or sintering of the surface material of the electrode substrate 11, resulting in a thick remelted layer near the laser-drilled area. The oxygen content of the remelted layer is significantly higher than that of the electrode substrate 11, causing oxidation of the electrode substrate 11 surface. At the same time, due to the uneven solidification and shrinkage of the material during the cooling process of laser drilling, tensile stress can be generated, which can easily cause microcracks on the processed surface, affecting the surface quality.

[0058] This application forms etched holes 111 on the surface of the electrode substrate 11 by etching. Compared with other hole-forming methods such as mechanical drilling and laser drilling, wet etching process has lower equipment requirements, lower processing difficulty, and lower cost. It is less likely to form residual stress and processing burrs. Furthermore, the surface material of the electrode substrate 11 will not melt and solidify during the processing, and the processed surface is less likely to produce defects such as remelted layers and microcracks. This is beneficial to give the electrolytic cathode 10 a better surface quality, which in turn helps to improve the quality of the porous current collector produced.

[0059] In some embodiments, before forming the mask layer 12 with patterned regions 121 on the surface of the electrode substrate 11, the method further includes degreasing and ultrasonic cleaning of the electrode substrate 11 to further improve the cleanliness of the electrode substrate 11 surface. Further, the ultrasonic cleaning time can be 10 min to 30 min, and the electrode substrate 11 is dried after ultrasonic cleaning.

[0060] In some embodiments, step S100, forming a mask layer 12 with patterned regions 121 on the surface of the electrode substrate 11, includes the following steps: first, forming the mask layer 12 on the surface of the electrode substrate 11, such as... Figure 2 As shown; then the mask layer 12 is sequentially patterned and developed to remove a portion of the mask layer 12 on the surface of the electrode substrate 11, thereby forming a mask layer 12 with patterned regions 121, as shown. Figure 3 As shown.

[0061] By employing the aforementioned methods of forming the mask layer 12, patterned exposure, and development, a mask layer 12 with patterned regions 121 can be conveniently formed on the surface of the electrode substrate 11. Furthermore, the material of the mask layer 12 can be one or more of, but not limited to, photoresist and phenolic resin. For example, the material of the mask layer 12 can be SU-8 3010 photoresist. The aforementioned mask layer 12 can be formed on the surface of the electrode substrate 11 by coating or deposition.

[0062] In some embodiments, etching includes one or more of electrochemical etching and chemical etching. Electrochemical or chemical etching processes can effectively form etched holes 111 of a certain depth on the surface of the electrode substrate 11, facilitating subsequent filling of the etched holes 111 with insulating material 13. The etched electrode substrate 11 is as follows: Figure 4 As shown.

[0063] Electrochemical etching involves placing the metal workpiece as the anode in a solution containing a specific electrolyte. When a DC power source is applied, the anode metal undergoes an oxidation reaction, losing electrons and becoming metal ions that enter the electrolyte. This dissolves and removes the metal surface, achieving the etching effect. Chemical etching, on the other hand, typically involves immersing the workpiece in a container of chemical etching solution. The etching solution comes into full contact with the workpiece surface, triggering a chemical reaction that also achieves the etching effect.

[0064] In some embodiments, the electrochemical etching includes the following steps: using the electrode substrate 11 as the anode to form an electrode pair with the cathode, etching the position of the patterned region 121 corresponding to the electrode substrate 11 in an electrochemical etching solution; the electrochemical etching solution is a sodium chloride solution or sodium bromide solution with a mass fraction of 0.1%~3%, and the current density of the electrochemical etching is 500 A / dm³. 2 ~10000A / dm 2 The etching depth is 10μm~200μm. Through the above electrochemical etching method, an etched hole 111 of a predetermined depth can be formed at the position of the electrode substrate 11 corresponding to the patterned area 121.

[0065] In some embodiments, the power supply used for electrochemical etching is a pulsed power supply. Using a pulsed power supply for electrochemical etching of the electrode substrate 11 surface facilitates the full removal of the etched products during pulse intervals, resulting in higher current density and smaller processing gaps, thereby effectively improving the material removal efficiency within the pulse width. Furthermore, the voltage of the pulsed power supply can be 22V~28V, the pulse frequency can be 500Hz~1000Hz, and the duty cycle can be 30%~50%, optionally 40%.

[0066] In some embodiments, the cathode material for electrochemical etching can be titanium, nickel, copper, graphite, stainless steel, etc., and the cathode shape can be a plate.

[0067] In some embodiments, chemical etching includes the following steps: immersing the electrode substrate 11 in a chemical etching solution and etching at a temperature of 50°C to 90°C for 0.5 to 3 hours. Through the above chemical etching process, etched holes 111 can also be formed on the surface of the electrode substrate 11 at positions corresponding to the patterned area 121.

[0068] Further, the chemical etching solution includes one or more of the following: nitric acid solution, hydrofluoric acid solution, sulfuric acid solution, hydrochloric acid solution, acetic acid solution, oxalic acid solution, and tartaric acid solution. In some specific examples, the chemical etching solution is a mixed acid solution of nitric acid and hydrofluoric acid, wherein the mass fraction of nitric acid is 10%~40% and the mass fraction of hydrofluoric acid is 5%~15%. After chemical etching, the electrode substrate 11 is ultrasonically cleaned for 30 min~60 min, and then dried at 40℃~80℃.

[0069] In some embodiments, the electrode substrate 11 is kept rotating during the etching process described above. This rotation of the electrode substrate 11 assists in the removal of reaction byproducts from the etched holes 111, thus helping to maintain the etching rate. In some specific examples, the rotational speed of the electrode substrate 11 is 0.5 m / min to 2 m / min. Understandably, the rotational speed of the electrode substrate 11 can be 0.5 m / min, 0.6 m / min, 0.7 m / min, 0.8 m / min, 0.9 m / min, 1.0 m / min, 1.1 m / min, 1.2 m / min, 1.3 m / min, 1.4 m / min, 1.5 m / min, 1.6 m / min, 1.7 m / min, 1.8 m / min, 1.9 m / min, 2 m / min, or any value within the range formed by any two of the above values.

[0070] In some embodiments, the electrode substrate 11 is roller-shaped. By setting the electrode substrate 11 into a roller shape, when the electrolytic cathode 10 is rotated to prepare porous current collectors, it is possible to electrolytically deposit porous current collectors on the electrolytic cathode 10 while simultaneously peeling the porous current collectors off the rotating electrolytic cathode 10. This facilitates continuous operation and improves the production efficiency of porous current collectors.

[0071] Furthermore, the electrode substrate 11 can be a hollow structure; the material of the electrode substrate 11 includes one or more of titanium, copper, iron, nickel, and their corresponding alloys. Titanium or titanium alloys can be selected. Titanium or titanium alloys have high strength and good corrosion resistance, exhibiting good stability in acidic and corrosive electrolyte environments, and are not easily corroded, which helps ensure the structural stability and service life of the electrolytic cathode 10.

[0072] In some embodiments, in step S300, insulating material 13 is filled into the etched holes 111 by means of dip coating or spraying, such as... Figure 5 As shown. The insulating material 13 may be one or more of epoxy resin, vinyl resin, phenolic resin and polyketone resin.

[0073] In some embodiments, after removing the mask layer 12, the preparation method further includes a polishing step on the surface of the electrode substrate 11. By polishing the surface of the electrode substrate 11, excess insulating material 13 can be removed, making the insulating material 13 in the etched holes 111 flush with the surface of the electrode substrate 11, thereby improving the surface quality of the electrolytic cathode 10.

[0074] Further, the surface polishing of the electrode substrate 11 includes the following steps: polishing the electrode substrate 11 with a 600-1000 mesh grinding wheel at a rotation speed of 1000 r / min to 1800 r / min. Polishing removes excess insulating material 13 from the surface of the electrode substrate 11. The polished electrode substrate 11 is as follows: Figure 6 As shown.

[0075] Please see Figure 7 This application provides an electrolytic cathode 10, which is prepared by the method described above. This electrolytic cathode 10 does not require re-preparation of the insulating region after each polishing process; the bonding force between the insulating material 13 and the electrode substrate 11 is strong; and the surface quality of the electrolytic cathode 10 is good. Using this electrolytic cathode 10 is beneficial for improving the quality of the produced porous current collector. Figure 7 The insulating material in the etched hole 111 is not shown.

[0076] Please see Figure 8 This application provides a porous current collector preparation apparatus 100, which includes an electrolytic cell, a cathode 101, and an anode 102. Both the cathode 101 and the anode 102 are placed in the electrolytic cell, and the cathode 101 is the electrolytic cathode 10 described above. Using the above-described porous current collector preparation apparatus 100, porous current collectors with good pore distribution uniformity and good surface quality can be obtained. Figure 8 The insulating material in the electrolytic cell and the etched hole 111 is not shown.

[0077] Please see Figure 8 In some embodiments, the electrolytic cell has arc-shaped walls, the anode 102 is arc-shaped and attached to the walls, and the cathode 101 is roller-shaped and rotatably placed in the arc-shaped groove of the anode 102. Thus, when producing porous current collectors using this porous current collector preparation apparatus 100, rotating the roller-shaped cathode 101 in the arc-shaped groove of the anode 102 allows for simultaneous electrolytic deposition of porous current collectors on the cathode 101 and simultaneous peeling of the porous current collectors from the cathode 101 by a peeling roller. This facilitates continuous operation, improves production efficiency, and is advantageous for producing thinner porous current collectors.

[0078] One embodiment of this application provides a method for preparing a porous current collector, which includes the following steps: An electrolyte solution is introduced into the electrolytic cell of the porous current collector preparation apparatus 100 described above, immersing the cathode 101 and anode 102 in the electrolyte solution; an electric current is applied to the cathode 101 and anode 102, thereby depositing a porous current collector on the cathode 101. During the electrolytic deposition process, the electrolyte solution in the electrolytic cell is continuously circulated, and the cathode 101 is kept rotating.

[0079] During electrolysis, metal ions in the electrolyte solution are electron-deposited at the cathode 101 to form a metal foil. Since the etched holes 111 on the surface of the cathode 101 (i.e., electrolytic cathode 10) are filled with insulating material 13, metal ions will not deposit onto the insulating material 13, thus forming a porous metal foil. The porous metal foil deposited on the surface of the cathode 101 is peeled off by a peeling roller to obtain a porous current collector.

[0080] Understandably, the electrolyte solution is a salt solution containing metal ions, wherein the type of metal ions can be determined based on the type of metal material of the porous current collector to be prepared. In some specific examples, when the porous current collector is a copper foil current collector, the electrolyte solution used can be an electrolyte solution containing 90 g / L to 110 g / L of sulfuric acid and 70 g / L to 90 g / L of copper sulfate.

[0081] It should be noted that the porous current collector can be either a positive electrode current collector or a negative electrode current collector. When the porous current collector is a positive electrode current collector, non-limiting examples of its metallic material may include one or more of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. When the porous current collector is a negative electrode current collector, non-limiting examples of its metallic material may include one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys.

[0082] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for preparing an electrolytic cathode, characterized in that, Includes the following steps: A mask layer with patterned regions is formed on the surface of the electrode substrate; The electrode substrate on which the mask layer is formed is etched to form etch holes at the positions of the electrode substrate corresponding to the patterned area; The etched holes are filled with insulating material; Remove the mask layer to obtain the electrolytic cathode.

2. The method for preparing an electrolytic cathode according to claim 1, characterized in that, The etching includes one or more of electrochemical etching and chemical etching.

3. The method for preparing an electrolytic cathode according to claim 2, characterized in that, The electrochemical etching includes the following steps: Using the electrode substrate with the mask layer formed thereon as the anode, an electrode pair is formed with the cathode, and etching is performed in an electrochemical etching solution; the electrochemical etching solution includes a sodium chloride solution or a sodium bromide solution with a mass fraction of 0.1% to 3%, and the current density of the electrochemical etching is 500 A / dm³. 2 ~10000A / dm 2 The etching depth is 10μm~200μm.

4. The method for preparing an electrolytic cathode according to claim 3, characterized in that, The power source for the electrochemical etching is a pulsed power source.

5. The method for preparing an electrolytic cathode according to claim 2, characterized in that, The chemical etching includes the following steps: immersing the electrode substrate in a chemical etching solution and etching at a temperature of 50°C to 90°C for 0.5h to 3h; the chemical etching solution includes one or more of nitric acid solution, hydrofluoric acid solution, sulfuric acid solution, hydrochloric acid solution, acetic acid solution, oxalic acid solution and tartaric acid solution.

6. The method for preparing an electrolytic cathode according to any one of claims 1 to 5, characterized in that, The electrode substrate is rotated during the etching process.

7. The method for preparing an electrolytic cathode according to any one of claims 1 to 6, characterized in that, The electrode substrate includes one or more of titanium, copper, iron, nickel, and their corresponding alloys.

8. The method for preparing an electrolytic cathode according to any one of claims 1 to 7, characterized in that, After removing the mask layer, the preparation method further includes a step of polishing the surface of the electrode substrate.

9. An electrolytic cathode, characterized in that, It is prepared by the method of any one of claims 1 to 8.

10. A porous current collector preparation device, characterized in that, It includes an electrolytic cell, a cathode, and an anode, wherein the cathode and the anode are both placed in the electrolytic cell, and the cathode is the electrolytic cathode as described in claim 9.

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