TWI845820B - Electrode structural material, method for preparing electrode structural material, and electrolytic capacitor - Google Patents

Abstract

The present invention proposes an electrode structural material and a method for preparing the electrode structural material, and an electrolytic capacitor. The method comprises: providing a substrate, and placing the substrate on a movable operating table; using a laser to melt a metal raw material in a melting furnace to form a metal melt, wherein the bottom of the melting furnace has a nozzle, the nozzle is located above the substrate, and allows the metal melt to be continuously deposited on the substrate; after the metal melt contacts the substrate, the operating table is moved along a predetermined trajectory to form a fiber layer formed by metal fibers on the substrate, wherein the inner diameter of the nozzle and the speed of moving the operating table can be adjusted to make the diameter D of the metal fiber meet 0.1 μm ≤ D ≤ 20 μm. The method can simply and quickly obtain the electrode structural material, and the electrode structural material has good bending strength and large specific capacity after being made into chemically formed foil, and is suitable for preparing the anode of the electrolytic capacitor.

Description

Electrode structural material, method for preparing electrode structural material, and electrolytic capacitor

The present invention relates to the field of materials, and in particular, to an electrode structural material and a method for preparing the electrode structural material, and an electrolytic capacitor.

Electrolytic capacitors are widely used in consumer electronic products due to their unique performance. In recent years, in order to meet the needs of integrated electronic products, miniaturization, high capacity and low cost have become the main development direction of electrolytic capacitors. Therefore, electrolytic capacitors are required to have better mechanical properties and larger specific capacity. Anode foil is a key raw material for electrolytic capacitors. In order to meet the above performance requirements of electrolytic capacitors, anode foil is also required to have higher specific capacity and better bending strength. At present, the main methods for forming anode foil are electrochemical corrosion technology and powder lamination technology.

However, current electrode structural materials, methods for preparing electrode structural materials, and electrolytic capacitors still need to be improved.

This application is made based on the inventor's discovery and understanding of the following facts and problems:

At present, the electrolytic foil used in electrolytic capacitors is mostly obtained by treating a flat metal substrate. Specifically, the electrochemical corrosion technology is to apply direct current to the aluminum foil in a chlorine-containing high-temperature acidic electrolyte, thereby forming a large number of tunnel holes on the surface of the aluminum foil. Therefore, in order to obtain a high-specific-volume corrosion-formed foil, the electrolytic corrosion needs to be carried out at a relatively low temperature and for a relatively long time, which results in the electrode foil having a low bending strength and is difficult to meet the miniaturization requirements. In addition, the acidic waste liquids generated by electrochemical corrosion, such as sulfuric acid, hydrochloric acid, and nitric acid, are difficult to handle, which increases environmental protection costs. In addition, electrochemical corrosion technology also has certain requirements for the type of metal substrate. The current electrochemical corrosion technology is mainly based on aluminum foil, which is difficult to produce precious metal electrolytic capacitors such as tantalum and niobium. The powder layering technology forms a layered electrode foil by coating metal powder on a metal carrier and then sintering it. Therefore, the layered foil has very high requirements for metal powder (particle size distribution, powder shape) and sintering technology. It is difficult to obtain powder with uniform particle size with existing equipment, and more VOC gas will be generated during the sintering process. In addition, the metal powder is accumulated in the form of particles, which is easy to crack after formation, resulting in low bending strength of the electrode foil. Therefore, if a new formed foil electrode structure and preparation method that can maintain high bending strength and high specific capacitance can be developed, it will be helpful to alleviate or even solve the above problems.

The present invention aims to solve one of the technical problems in the above-mentioned related technologies to at least a certain extent. To this end, the present invention proposes a method for preparing an electrode structural material. The method comprises: providing a substrate, and placing the substrate on a movable operating table; using a laser to melt the metal raw material in the furnace to form a metal melt, the bottom of the furnace has a nozzle, the nozzle is located above the substrate, and the metal melt is continuously deposited on the substrate; after the metal melt contacts the substrate, the operating table is moved according to a predetermined trajectory to form a fiber layer formed by metal fibers on the substrate; wherein, adjusting the inner diameter of the nozzle and the speed of moving the operating table can make the diameter D of the metal fiber meet the following conditions: 0.1 μm ≤ D ≤ 20 μm. The method can simply and quickly obtain the electrode structural material, and the electrode structural material has good bending strength and large specific capacity after being made into chemically formed foil, and is suitable for preparing the anode of the electrolytic capacitor.

According to an embodiment of the present invention, the melting furnace is a ceramic melting furnace, and the laser light source is configured to melt the metal raw material by irradiation, thereby obtaining a metal melt in a simple manner.

According to an embodiment of the present invention, the inner diameter of the nozzle is 0.5-1000 μm, and the speed at which the operating platform moves relative to the nozzle is 50-150 mm/s. Thus, the diameter of the metal fiber can be better controlled to obtain an electrode structure material with a relatively ideal specific capacity.

According to an embodiment of the present invention, the melting furnace is further connected to a fluid control thruster, and the fluid control thruster can control the melt flow rate of the metal melt to 1-20 mL/h. Thus, the flow rate of the metal melt can be easily controlled.

According to an embodiment of the present invention, the predetermined track includes a first predetermined pattern and a second predetermined pattern; the first predetermined pattern includes a plurality of parallel lines extending along a first direction; the second predetermined pattern includes a plurality of parallel lines extending along a second direction; the distance between two adjacent parallel lines in the first predetermined pattern is 0.1-1000 μm; the distance between two adjacent parallel lines in the second predetermined pattern is 0.1-1000 μm. Thus, the metal fibers in the formed fiber layer are arranged regularly, and are conducive to improving the specific capacity of the electrode structure material.

According to an embodiment of the present invention, at least one of the following operations is further included: repeatedly moving the operating stage according to the first predetermined pattern and the second predetermined pattern to form the fiber layer formed by stacking multiple sublayers formed by metal fibers on the substrate; and the substrate has a first surface and a second surface opposite to each other. After the fiber layer is formed on the first surface, the second surface of the substrate is placed relative to the furnace and the operation of forming the fiber layer is repeated to form the fiber layer on the second surface. In this way, fiber layers can be formed on both sides of the substrate to form a sandwich structure, which is beneficial to further improve the specific capacity of the electrode structure material.

According to an embodiment of the present invention, the material forming the substrate and the metal raw material includes valve metals, and the valve metals independently include aluminum, tantalum, niobium, titanium, zirconium or tantalum. This is conducive to further improving the performance of the electrode structure material obtained by the method.

In another aspect of the present invention, an electrode structural material is provided. The electrode structural material comprises: a substrate; a fiber layer, wherein the fiber layer comprises a plurality of regularly arranged metal fibers, and the diameter D of the metal fibers satisfies 0.1 μm ≤ D ≤ 20 μm. The electrode structural material has advantages such as high specific capacity and good bending performance, and is more suitable for preparing anode foil of electrolytic capacitors.

According to an embodiment of the present invention, the electrode structural material is obtained by the method described above. Therefore, the electrode structural material has at least one of the advantages of low preparation cost and environmental friendliness.

In another aspect of the present invention, an electrolytic capacitor is provided. The electrolytic capacitor comprises: an anode, the anode comprises the electrode structural material described above; and a cathode, the cathode comprises an electrolyte and a conductive electrode. Thus, the electrolytic capacitor has all the characteristics and advantages of the electrode structural material described above, which will not be elaborated here. In general, the electrolytic capacitor has at least one of the advantages of high specific capacity, low electrochemical impedance, and good anode mechanical properties.

The following describes in detail embodiments of the present invention, examples of which are shown in the drawings. The embodiments described below with reference to the drawings are exemplary and intended to be used to explain the present invention, and should not be construed as limiting the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meanings as those commonly understood by those with ordinary knowledge in the technical field to which the present invention belongs. All patents and publications related to the present invention are incorporated herein by reference as a whole. The term "comprising" or "including" is an open expression, that is, including the contents specified in the present invention, but does not exclude other aspects of the content.

In one aspect of the present invention, a method for preparing an electrode structural material is provided. The method uses a laser to heat a metal powder or a block to melt to form a metal melt, and uses a movable operating table to move a substrate along a predetermined path so that the metal melt forms regularly arranged metal fibers on the substrate. A plurality of metal fibers are stacked to form a fiber layer, thereby obtaining the electrode structural material.

As mentioned above, the performance of the chemically-formed foil formed based on the planar foil, whether by electrochemical corrosion technology or powder lamination technology, needs to be improved. The electrode structural material obtained according to the embodiment of the present invention has a fiber layer on a planar metal substrate, and the fibers are stacked in a certain arrangement, thereby providing the electrode structural material with a surface morphology that is more suitable for forming an anode foil of an electrolytic capacitor. Specifically, on the one hand, the fiber layer formed by the metal fibers can have a higher surface area, and the surface area of the chemically-formed foil after chemical formation is also larger. On the other hand, the chemical formation can be based only on the fiber layer, thereby providing good mechanical support for the chemically-formed foil finally obtained by using a substrate with less damaged surface morphology or even uncorroded. Moreover, the fiber layer formed by the accumulation of metal fibers becomes the decisive factor in determining the pore size range and pore size distribution uniformity of the anode foil surface. Therefore, compared with the structure formed by electrochemical corrosion or sintering, the surface morphology of the fiber layer is more controllable, and the same batch of products or different batches of products have better repeatability. In addition, the method uses laser heating of metal materials, does not involve complex sintering processes or environmentally unfriendly acid corrosion processes, and therefore has lower environmental costs. The material of the electrode structure is no longer limited to aluminum, and can be formed by any one of aluminum, tantalum, and niobium, including but not limited to aluminum.

The following is a detailed description of each step of the method according to a specific embodiment of the present invention. Specifically, referring to FIG1 , the method comprises:

Step S100: providing a substrate;

According to an embodiment of the present invention, a substrate is first provided in step S100. As mentioned above, the specific material of the substrate is not particularly limited, for example, it can be a valve metal, specifically including but not limited to aluminum, tantalum, niobium, titanium, zirconium or tantalum. The thickness of the substrate is also not particularly limited, and a person with ordinary knowledge in the relevant technical field can design it according to the specific requirements of the required chemical foil. Since the "sandwich" thickness of the electrode structure material obtained according to the method of the present invention after chemical formation is basically provided by the substrate, and the thickness of the substrate will not be significantly reduced during the chemical formation process, the sandwich thickness of the chemical foil can be controlled by selecting the thickness of the substrate. For example, according to a specific embodiment of the present invention, the thickness of the substrate can be 5-80 μm, for example, 10-50 μm. The inventors have found that if the thickness of the substrate is too thin, the tensile strength of the electrode material formed by the chemical foil will be insufficient when the anode foil is prepared, while if the thickness of the substrate is too thick, the bending strength of the electrode material will be reduced. When the thickness of the substrate is within the above range, it can meet the requirements of most electrolytic capacitor electrodes. According to some specific embodiments of the present invention, the thickness of the substrate can be 10-40 μm, specifically 20-30 μm, for example, 25 μm, 28 μm, etc. Thereby, the mechanical properties of the electrode structural material can be further improved. It can be understood by those with ordinary knowledge in the relevant technical field that the step of providing the substrate may include the step of forming a planar substrate, and may also include cutting, grinding, cleaning and other operations on the planar substrate.

Step S200: using laser to form a metal melt to form a fiber layer on the substrate;

According to an embodiment of the present invention, a metal melt is formed by laser in step S200 and a fiber layer is formed. Specifically, in step S200, a metal raw material in a furnace is melted by laser to form a metal melt, and the metal melt is continuously deposited on a substrate. After the metal melt contacts the substrate, an operating table is moved along a predetermined trajectory to form metal fibers on the substrate. The regularly arranged metal fibers are stacked to form a fiber layer.

Specifically, referring to FIG. 2 , the operation of forming the metal melt may be performed in a sealed container, such as a sealed operation box 7, which may be filled with a protective gas. The metal raw material may be placed in a melting furnace 2, and irradiated with a laser 1 so that the metal is completely melted and ready for use. The metal raw material may also be a valve metal, such as aluminum, tantalum, niobium, titanium, zirconium or tantalum, and the specific material is not particularly limited. The metal raw material may be a powder or a block, and the morphology of the metal raw material is not particularly limited, as long as the metal melt can be formed using the laser 1. The melting furnace 2 may be a high-temperature resistant melting furnace, such as a ceramic melting furnace. The mass of the metal raw material in the melting furnace 2 can be 0.1-100 kg, in order to prevent the formation of too little metal melt to affect the subsequent metal fiber direct writing process, or the melted metal is too much, such as the melt re-condenses and blocks the drain 8 at the bottom of the melting furnace 2. The protective gas can be one or a combination of argon, nitrogen, and argon-hydrogen mixed gas. The power of the laser 1 is not particularly limited, as long as the metal raw material can be melted. Those with ordinary knowledge in the relevant technical field can select it according to the specific material of the metal raw material. According to some embodiments of the present invention, the power range of the laser 1 can be 10 ⁶ ~10 ⁸ W/cm ³ .

Before forming the metal melt, the substrate 100 is placed on an operating table. The operating table can be an x-y dual-axis control slide 9 equipped with a liftable base 6. After the metal melt is formed, the direct writing operation of the metal fiber can be performed on the substrate 100 using the melting furnace 2 and the operating table that can move relative to the nozzle 8. The nozzle 8 can be connected to a fluid propulsion control pump 3 to control the flow rate of the metal melt. By setting appropriate metal melt direct writing parameters, a fiber layer formed by 3D metal fibers with an ordered structure can be obtained on the surface of the metal substrate.

According to a specific embodiment of the present invention, the metal melt direct writing parameters may include the moving path of the operating platform, the inner diameter of the nozzle 8 at the bottom of the melting furnace 2, the metal melt supply rate, the operating platform moving rate and the direct writing distance (i.e., the distance from the nozzle 8 to the surface of the substrate 100), etc. By designing the above parameters, a continuous metal fiber with a moderate diameter and arrangement spacing can be obtained on the substrate 100. Multiple layers of regularly arranged metal fibers are stacked to form a regular network structure, and a 3D fiber layer can be obtained. Therefore, the fiber layer can provide a larger specific surface area for the electrode structural material, so that the formed foil can have a larger specific capacity after being formed, and is suitable for application as an electrode material for electrolytic capacitors.

According to a specific embodiment of the present invention, the diameter D of the metal fiber formed in this step can satisfy 0.1 μm ≤ D ≤ 20 μm. Specifically, it can also be 0.3-20 μm, or can be no greater than 10 μm, for example, it can be 0.5 μm, 0.8 μm, 1 μm, 2 μm, 3 μm, 5 μm, 7 μm, 8 μm, 15 μm, etc. The inventors have found that the fiber with a diameter within the above range can effectively increase the specific surface area of the electrode structure material, thereby improving the specific capacity of the formed foil obtained using the electrode structure material, and the specific surface area will not be effectively increased due to the excessively large fiber diameter, nor will it be consumed in the formation process due to the excessively small fiber diameter.

Specifically, the diameter of the metal fiber on the substrate 100 can be controlled by the inner diameter of the nozzle 8, the moving speed of the operating table, and the flow rate of the metal melt. As mentioned above, after the metal raw material in the melting furnace 2 forms a metal melt, it is continuously deposited downward from the nozzle 8. When the metal melt contacts the substrate 100 below, a "meniscus" type contact surface is formed on the surface of the substrate 100. At this time, the operating table can be moved according to a predetermined path to realize the metal fiber. The direction of movement of the operating table determines the arrangement of the metal fiber, and during the movement of the operating table, the metal melt falling on the substrate 100 will be stretched, thereby forming a metal fiber with a diameter slightly smaller than the diameter of the nozzle 8. Therefore, the diameter of the metal fiber formed on the substrate 100 can be controlled by controlling the inner diameter of the nozzle 8, the moving speed of the operating table, and the flow rate of the metal melt. Specifically, the inner diameter of the nozzle 8 can be 0.5-1000 μm. For example, it can be 0.5-10 μm, and specifically can be 0.5-2 μm. The speed at which the operating table moves relative to the nozzle 8 can be 50-150 mm/s, and specifically can be 50-100 mm/s. In this way, the diameter of the metal fiber can be better controlled to obtain an electrode structure material with a more ideal specific capacity. The melt flow rate can be controlled to be 1-20 mL/h, for example, 3 mL/h, 5 mL/h, 6 mL/h, 8 mL/h, 10 mL/h, 15 mL/h, etc. The direct writing distance is 0.5-3 mm, that is, the distance between the nozzle 8 and the substrate 100 can be 0.5-3 mm. Specifically, it can be 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.5 mm, etc. Thus, a continuous metal fiber layer with an ideal specific capacity can be formed.

There is no particular restriction on the predetermined trajectory of the operation table movement, and it can be designed according to the 3D arrangement of the fiber layer to be obtained as needed. Specifically, the movement path of the operation table can be a 3D movement path, which can be pre-programmed by including but not limited to Auto CAD, Origin, Excel or C language and imported into the operating system, and realized by controlling the x-y double-axis control slide 9. Specifically, with reference to Figures 5 and 6, the predetermined trajectory can include a first predetermined figure 210' and a second predetermined figure 220'. Specifically, the first predetermined figure 210' can include a plurality of parallel lines extending along the first direction, and two adjacent parallel lines are connected end to end to form a bow-shaped curve. The operating platform may first move according to the first predetermined pattern 210', thereby forming metal fibers of the shape shown in 210' on the substrate 100. The distance D1 between two adjacent parallel lines is 0.1-1000 μm. Subsequently, the operating platform may first move according to the second predetermined pattern 220', thereby forming metal fibers of the shape shown in 220' on the substrate 100. The angle between the first predetermined direction and the second predetermined direction is the angle between the metal fibers of two adjacent sublayers in the formed fiber layer. The first predetermined direction and the second predetermined direction may be perpendicular to each other, that is, they may be the x direction and y direction of the x-y dual-axis control slide 9. The distance D2 between two adjacent parallel lines in the second predetermined pattern 220' may also be 0.1-1000 μm. According to a preferred embodiment of the present invention, the distance D1 between two parallel lines in the first predetermined pattern 210' and the distance D2 between two parallel lines in the second predetermined pattern 220' may be equal. Thus, a metal fiber network with a regular tic-tac-toe arrangement may be finally formed on the substrate 100. According to some examples of the present invention, the ranges of the distance D1 and the distance D2 may be 0.05-5 μm, 0.1-1 μm, respectively, or may be 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 30 μm, 40 μm, 60 μm, 100 μm, etc., respectively, or may be 200 μm, 300 μm, or greater than 500 μm, etc. It is understood by those skilled in the art that the distance between two adjacent lines in the predetermined pattern in this step is the distance between two adjacent metal fibers in the obtained fiber layer.

Subsequently, the operating table can be moved multiple times according to the first predetermined pattern 210' and the second predetermined pattern 220' to form a fiber layer formed by stacking multiple sublayers. According to an embodiment of the present invention, the thickness of the fiber layer, the number of sublayers, etc. are not particularly limited. For example, the total thickness of the fiber layer can be 20-80 μm. In this way, the performance of the electrode structure material can be further improved. For example, a fiber layer that is too thin can hardly provide a sufficient specific surface area for the electrode structure material, and the specific capacity of the resulting formed foil is not ideal. A fiber layer that is too thick may cause undesirable phenomena such as the sublayer falling off from the substrate 100, thereby making the electrode structure unstable. According to some other examples of the present invention, the above-mentioned fiber layer can be formed on both opposite surfaces of the substrate 100. Specifically, referring to FIG. 4 , after the fiber layer 200A is formed on the first surface of the substrate 100, the second surface of the substrate 100 can be placed relative to the melting furnace 2, and the operation of forming the fiber layer is repeated to form the second fiber layer 200B. The fiber layer 200A and the second fiber layer 200B can both have a plurality of stacked sublayers 210, 220 structures. Thus, the specific capacity of the electrode structure material can be further improved.

It should be particularly noted that the electrode structural material prepared by the method may also have an oxide film, which covers at least part of the surface of the metal fiber. The oxide film may be formed by chemical formation. In other words, the electrode structural material may be chemically formed. The electrode structural material obtained by the method includes but is not limited to medium-voltage, high-voltage and ultra-high-voltage chemical foils. The electrode structural material obtained by the method has a high specific capacity characteristic that is difficult to achieve by electrochemical corrosion technology, which is conducive to the miniaturization of electrolytic capacitors. Moreover, the electrode structural material is suitable for any one of valve metal (such as aluminum, tantalum, niobium, titanium, zirconium or niobium, etc.) electrolytic capacitors. The surface layer of the electrode structure material of the present invention has a metal fiber structure, so it has better toughness than the powder structure formed by powder lamination technology, and the bending strength of the electrode material is also higher. The upper and lower layers of metal fibers in the fiber layer are cross-stacked at a certain angle, which can effectively avoid the electrolyte from bypassing between the metal fibers, so the electrode material has lower loss and can be used to prepare electrolytic capacitors with low ESR.

In another aspect of the present invention, an electrode structural material is provided. Referring to FIG. 3 and FIG. 4 , the electrode structural material includes a substrate 100 and a fiber layer 200, wherein the fiber layer 200 includes a plurality of regularly arranged metal fibers, and the diameter D of the metal fibers satisfies 0.1 μm ≤ D ≤ 20 μm. The electrode structural material has advantages such as high specific capacity and good bending performance, and is more suitable for preparing anode foil of an electrolytic capacitor.

According to an embodiment of the present invention, the electrode structural material can be obtained by the method described above. The specific structure of the electrode structural material has been described in detail above and will not be repeated here. In general, the electrode structural material has at least one of the advantages of low preparation cost and environmental friendliness. Specifically, the substrate 100 and the fiber layer 200 are both formed of metal. The materials forming the substrate 100 and the metal fiber are independently valve metals, which may specifically include aluminum, tantalum, niobium, titanium, zirconium or tantalum. The electrode structural material has the advantage of being suitable for preparing anode foil of an electrolytic capacitor. The prepared anode foil has a high specific capacity and high bending strength, and can alleviate the bypass of electrolyte, thereby being beneficial to reducing the impedance of the electrolytic capacitor.

The electrode structural material may also have an oxide film, which covers at least part of the surface of the metal fiber. The oxide film may be formed by chemical treatment and used in applications such as electrodes of electrolytic capacitors. The electrode structural material may include but is not limited to medium voltage, high voltage and ultra-high pressure chemical foils. The electrode structural material has a high specific capacity characteristic that is difficult to achieve through electrochemical corrosion technology, which is conducive to the miniaturization of electrolytic capacitors. Moreover, the electrode structural material is suitable for any one of electrolytic capacitors such as aluminum, tantalum and niobium. The surface of the electrode structural material of the present invention has a metal fiber structure, so it has better toughness than the powder structure formed by powder lamination technology, and the bending strength of the electrode material is also higher. The upper and lower layers of metal fibers in the fiber layer 200 are cross-stacked at a certain angle, which can effectively prevent the electrolyte from bypassing between the metal fibers. Therefore, the electrode material has lower loss and can be used to prepare an electrolytic capacitor with low ESR.

In another aspect of the present invention, an electrolytic capacitor is provided. According to an embodiment of the present invention, the electrolytic capacitor includes: an anode and a cathode, wherein the anode includes the electrode structural material described above. The cathode may include an electrolyte and a conductive electrode. The electrolytic capacitor has all the characteristics and advantages of the electrode structural material described above, which will not be elaborated here. In general, the electrolytic capacitor has at least one of the advantages of high specific capacity, low electrochemical impedance, and good anode mechanical properties.

In the examples described below, unless otherwise stated, all temperatures are in degrees Celsius. The reagents used can be purchased from the market or prepared by the methods described in the present invention.

Embodiment 1:

A molten metal micro-nanofiber direct writing device was built. The main accessories include: a sealed operating box, a laser, a melting furnace, a nozzle, a fluid propulsion pump, and a dual-axis moving collector. The device structure diagram is shown in Figure 2.

First, 100 g of aluminum powder was added to the ceramic melting furnace, argon was selected as the protective atmosphere of the sealed box, the laser power was set to 10 ⁷ W/cm ³ , and the aluminum powder was heated until it was completely molten; then, a 30 μm thick aluminum substrate was placed on the surface of the mobile collector, the inner diameter of the nozzle was selected to be 1 μm, and the melt feed rate was controlled by a fluid propulsion pump. When the melt reached the surface of the aluminum substrate, it would quickly form a "meniscus" contact surface at the junction with the substrate. The program-controlled xy biaxial mobile collector pulled the substrate to move and directionally collect the formed molten metal fibers. The melt feed rate is 5 mL/h, the receiving distance between the tip of the nozzle and the substrate is 1 mm, the trajectory of the biaxial moving collector is set to an equidistant bow-shaped return path (as shown in Figure 2), the program sets the metal fiber spacing on the substrate to 4.0 μm, and the slide movement speed is 100 mm/s. Bow-shaped metal fibers are formed in both the x-direction and the y-direction of the biaxial moving collector, and the above steps are repeated many times until the thickness of the fiber layer formed by the metal fiber stacking is 50 μm. The same step is used on the other side of the aluminum substrate, and the final electrode material thickness is 130 μm. The SEM (scanning electron microscope) image of the electrode structural material prepared in Example 1 is shown in Figure 7. The aluminum fibers formed have a diameter of about 1 μm and are arranged in parallel on the substrate at a programmed interval of 4.0 μm in the same direction. The aluminum fibers are evenly and continuously distributed without obvious breaks.

Embodiment 2:

The remaining operations are the same as those in Example 1, except that the distance between the metal fibers on the substrate is set to 0.8 μm in the bow-shaped return path program, and the sliding speed is 80 mm/s. The diameter of the aluminum fiber is about 1.8 μm. The other side of the aluminum substrate is subjected to the same step, and the thickness of the electrode material is finally 130 μm.

Embodiment 3:

The remaining operations are the same as those in Example 1, except that the distance between the metal fibers on the substrate is set to 0.8 μm in the bow-shaped return path program, and the sliding speed is reduced to 70 mm/s, resulting in an aluminum fiber diameter of about 2.0 μm. The same step is used on the other side of the aluminum substrate, and the final electrode material thickness is 130 μm.

Embodiment 4:

The remaining operations are the same as those in Example 1, except that the distance between the metal fibers on the substrate is set to 1.0 μm in the bow-shaped return path program, and the sliding speed is 80 mm/s, so that the diameter of the aluminum fiber is about 1.8 μm. The stacking thickness of the metal fiber is controlled to be 50 μm. The same step is used on the other side of the aluminum substrate, and the thickness of the electrode material is finally obtained to be 130 μm.

Embodiment 5:

The remaining operations are the same as those in Example 1, except that the distance between the metal fibers on the substrate is set to 1.0 μm in the bow-shaped return path program, and the sliding speed is 80 mm/s. The stacking thickness of the metal fibers is controlled to be 50 μm. The diameter of the aluminum fibers obtained is about 2.0 μm. The other side of the aluminum substrate adopts the same step, and the thickness of the electrode material is finally obtained to be 130 μm.

Comparative Example 1:

Using hydrochloric acid and sulfuric acid as the pore bath solution, the temperature was controlled at 68°C, and a 130 μm thick aluminum foil with a purity of 99.99% was subjected to 6-level DC corrosion with an average current density of 0.42 A/ ^cm2 for 25 seconds to make the sandwich layer thickness about 7 μm. The pore size was then expanded in a nitric acid solution at 72°C with a current density and time of 0.15 A/ ^cm2 and 480 seconds, respectively.

Performance Test:

The samples obtained in Examples 1 to 5 and Comparative Example 1 were anodic-formed in a boric acid aqueous solution by applying a voltage of 520 V, and the specific volume, bending strength and residual thickness of the formed foil were tested. The test results are shown in Table 1 below: Table 1 520V specific capacitance (μF/cm ² ) R3.5 bending strength (return) Residual thickness (μm) Fiber diameter (μm) Pitch (μm) Embodiment 1 0.41 62 30 1.0 4.0 Embodiment 2 1.28 59 30 1.8 0.8 Embodiment 3 1.21 63 30 2.0 0.8 Embodiment 4 0.95 65 30 1.8 1.0 Embodiment 5 0.81 55 30 2.0 1.0 Comparative Example 1 1.02 35 7 - -

As can be seen from Table 1, controlling the metal fiber spacing and metal fiber diameter on the aluminum substrate can effectively adjust the 520V formation voltage capacity of the formed foil. The metal fiber spacing is precisely controlled by a programmed double-axis slide. The smaller the metal fiber spacing, the higher the specific surface area of the formed foil, and the higher its 520 V formation specific capacity. The metal fiber diameter is mainly determined by the inner diameter of the nozzle and is appropriately modified by the traction of the slide. When the fiber diameter is controlled at about 1.8 μm, the 520 V formed foil has a more ideal specific capacity. It can be seen from the embodiments and comparative examples that based on the molten aluminum metal forming technology, a high specific capacity and high bending formed foil can be obtained.

In the description of this specification, the descriptions with reference to the terms "one embodiment", "another embodiment", "embodiment", "example", etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in an appropriate manner. In addition, where there is no contradiction, a person of ordinary skill in the art may combine and combine different embodiments or examples described in this specification and features of different embodiments or examples.

Although the embodiments and examples of the present invention have been shown and described above, it can be understood that the above embodiments and examples are exemplary and cannot be understood as limitations of the present invention. A person having ordinary knowledge in the relevant technical field can change, modify, replace and modify the above embodiments and examples within the scope of the present invention.

1: Laser 2: Furnace 3: Fluid propulsion control pump 6: Base 7: Sealed operating box 8: Nozzle 9: x-y dual-axis control slide 100: Substrate 200: Fiber layer 200A: Fiber layer 200B: Second fiber layer 210,220: Sublayer 210’: First predetermined pattern 220’: Second predetermined pattern S100,S200: Steps D1,D2: Distance

[Figure 1] is a schematic diagram of a process for preparing an electrode structural material according to an embodiment of the present invention. [Figure 2] is a schematic diagram of an apparatus for preparing an electrode structural material according to another embodiment of the present invention. [Figure 3] is a schematic diagram of the structure of an electrode structural material according to an embodiment of the present invention. [Figure 4] is a schematic diagram of the structure of an electrode structural material according to another embodiment of the present invention. [Figure 5] is a schematic diagram of the structure of a first predetermined pattern according to an embodiment of the present invention. [Figure 6] is a schematic diagram of the structure of a second predetermined pattern according to an embodiment of the present invention. [Figure 7] is a scanning electron microscope photograph of the electrode structural material prepared according to Embodiment 1 of the present invention.

S100,S200: Steps

Claims (9)

A method for preparing an electrode structural material comprises: providing a substrate and placing the substrate on a movable operating table; using a laser to melt a metal raw material in a furnace to form a metal melt, wherein the bottom of the furnace has a nozzle, the nozzle is located above the substrate, and allows the metal melt to be continuously deposited on the substrate; after the metal melt contacts the substrate, the operating table is moved along a predetermined trajectory to form a fiber layer formed of metal fibers on the substrate; wherein the inner diameter of the nozzle and the speed of moving the operating table are adjusted so that the diameter D of the metal fiber meets: 0.1 μm

D

20μm; wherein the furnace is a ceramic furnace, and the laser light source is configured to melt the metal raw material by irradiation. The method as described in claim 1, wherein the inner diameter of the nozzle is 0.5-1000μm; the speed at which the operating table moves relative to the nozzle is 50-150mm/s. The method as described in claim 1, wherein the melting furnace is further connected to a fluid control thruster, and the fluid control thruster can control the melt flow rate of the metal melt to 1-20mL/h. A method as described in any one of claims 1 to 3, wherein the predetermined trajectory includes a first predetermined pattern and a second predetermined pattern; the first predetermined pattern includes a plurality of parallel lines extending along a first direction; the second predetermined pattern includes a plurality of parallel lines extending along a second direction; the distance between two adjacent parallel lines in the first predetermined pattern is 0.1-1000μm; the distance between two adjacent parallel lines in the second predetermined pattern is 0.1-1000μm. The method as described in claim 4 further comprises at least one of the following operations: Repeating the step of moving the operating table according to the first predetermined pattern and the second predetermined pattern multiple times to form the fiber layer formed by stacking multiple sublayers formed by metal fibers on the substrate; and the substrate has a first surface and a second surface opposite to each other, after the fiber layer is formed on the first surface, the second surface of the substrate is placed relative to the furnace, and the operation of forming the fiber layer is repeated to form the fiber layer on the second surface. The method as described in claim 1, wherein the substrate and the metal raw material include valve metals, and the valve metals independently include aluminum, tantalum, niobium, titanium, zirconium or tantalum. An electrode structure material obtained by using the method described in any one of claims 1 to 6. The electrode structural material as described in claim 7, wherein the fiber layer includes a plurality of regularly arranged metal fibers. An electrolytic capacitor, comprising: an anode, the anode comprising the electrode structural material as described in claim 7 or 8; a cathode, the cathode comprising an electrolyte and a conductive electrode.