KR20240018049A - Silicon anode having a three-dimensional porous structure and method for manufacturing the same - Google Patents

Abstract

The present invention relates to a silicon anode with a three-dimensional porous structure and a method of manufacturing the same. The silicon anode of the three-dimensional porous structure is made by preparing a slurry containing silicon, a pore former, porous carbon as a conductive material, and a binder, coating the slurry on a substrate to form a coating layer, and then forming pores through heat treatment. It is manufactured. The silicon anode with the three-dimensional porous structure has a simple manufacturing process and reduces costs by simultaneously adding silicon and a pore-forming agent to form a slurry. In addition, by forming spherical pores, it has a three-dimensional porous structure, which increases the reaction area and improves long-term stability by being less affected by changes in the volume of the electrode and mechanical stress.

Description

Silicon anode having a three-dimensional porous structure and method for manufacturing the same}

The present invention relates to a silicon anode having a three-dimensional porous structure in which pores are formed through a pore former and a method of manufacturing the same.

Recently, as the demand for devices with high energy density has increased, large-capacity energy storage devices have become important. Therefore, lithium-ion capacitors are attracting attention as a next-generation hybrid energy storage device that combines the advantages of existing electric double layer capacitors with excellent output and lithium-ion batteries with high energy density.

Lithium metal anodes, which are generally used to manufacture large-capacity energy storage devices, have a theoretical capacity of 3,860 mAh/g, low redox potential, and fast oxidation/reduction reaction rates. However, the lithium metal anode had difficulty in commercialization due to its high chemical reactivity and low battery life and stability due to dendrite formation due to uneven electrodeposition/desorption. In addition, when using a generally planar lithium metal anode, there is a problem in that the output characteristics are disadvantageous because it has a small reaction area compared to a commercial electrode with a three-dimensional structure.

Therefore, to solve this problem, a silicon cathode capable of insertion/detachment of lithium ions was used in the lithium ion capacitor. The silicon cathode has a theoretical capacity of about 4,200 mAh/g and has high energy density and power density. However, electrode cracks are easily formed in the silicon anode due to volume change and mechanical stress during the insertion/desorption of lithium ions during charge/discharge. In addition, a problem occurred in which the electrode collapsed due to the phenomenon of the electrode being peeled off from the current collector, resulting in a decrease in cycle life. Therefore, a technology that can solve electrode collapse caused by volume expansion/contraction of the silicon cathode is needed.

The first technical problem to be achieved by the present invention is to provide a silicon anode having a three-dimensional porous structure using a pore forming agent.

The second technical problem to be achieved by the present invention is to provide a method of manufacturing a silicon anode having a three-dimensional porous structure in order to achieve the first technical problem.

In order to achieve the first technical problem described above, the present invention provides a silicon anode having a three-dimensional porous structure in which pores are formed. The silicon anode is composed of a silicon anode having spherical pores through a pore forming agent.

In order to achieve the second technical problem described above, the present invention provides a method for manufacturing a silicon anode with a three-dimensional porous structure. For the silicon anode, a slurry containing silicon, conductive carbon as a conductive material, a binder, and a pore former is prepared and coated on a substrate to produce a three-dimensional silicon anode, and then heated to remove the pore former. It can be obtained by forming pores in the silicon anode.

In the present invention, by including a pore-forming agent during slurry production, the electrode active material and the pore-forming agent can be applied simultaneously, simplifying the electrode manufacturing process and reducing costs.

By forming an electrode with a three-dimensional porous structure, output characteristics can be improved by increasing the reaction area compared to electrodes with a flat structure and electrodes without pores. In addition, due to the presence of pores, the influence of volume change and mechanical stress is small, so electrode cracks are not easily formed, which can increase cycle life.

1 is a three-dimensional diagram exemplarily showing the manufacturing process of an electrode according to a manufacturing example of the present invention.
Figure 2 is a flowchart of a method for manufacturing a silicon anode with a three-dimensional porous structure.
Figure 3 is a schematic diagram of equipment for synthesizing pore forming agents.
Figure 3 4 is a SEM (Scanning Electron Microscopy) image of the pore former formed through Preparation Example 1.
Figure 5 is a graph of the thermogravimetric analysis results of the pore forming agent.
Figure 6 is an SEM image of the manufacturing example and comparative example of the present invention.
Figure 7 is an SEM image according to a comparative example of the present invention.
Figure 8 is a graph showing the results of analysis of cycle life characteristics of production examples and comparative examples of the present invention.
Figure 9 is a Ragone plot of a lithium ion capacitor including manufacturing examples and comparative examples of the present invention.
Figure 10 is a graph of half-cell test results for cycles according to discharge capacity of the manufacturing examples and comparative examples of the present invention.

Since the present invention can be subject to various changes and have various forms, specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless explicitly defined in the present application, should not be interpreted in an ideal or excessively formal sense. No.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the attached drawings.

Example

1 is a schematic diagram illustrating the manufacturing process of an electrode according to a preferred embodiment of the present invention.

Referring to FIG. 1, the schematic diagram on the left is a schematic diagram of an electrode composed of silicon 20, a pore former 30, conductive carbon 40 as a conductive material, and binder 50 in a three-dimensional structure on a substrate 10. When the electrode is heat treated, the pore forming agent 30 is removed and a spherical pore 51 is formed in its place, taking the form shown in the schematic diagram on the right.

The pore forming agent includes one or more selected from the group consisting of polystyrene, polymethylmethacrylate, polyvinylpyrrolidone, and polytetrafluoroethylene. It is more preferable to use polystyrene as the pore forming agent. Since the polystyrene has a spherical shape, when heated, pores with a large surface area can be formed to increase the efficiency of the electrode.

The pore forming agent preferably has a diameter of 100 nm to 10 um. If the diameter is less than 100 nm, the pores formed are very small, making it difficult to improve the performance of the electrode, and if the diameter is greater than 10 um, the pores formed are very large, which may make it difficult to maintain the three-dimensional structure.

The binder is polyimide, poly(amide imide) (PAI), polyvinylidene fluoride (PVDF), vinylidene fluoride/hexafluoropropylene copolymer (Hexafluoropropylenevinylidenefluoride copolymer) , Polyacrylonitrile (PAN), Poly (methyl methacrylate), PMMA), Polytetrafluoroethylene (PTFE), Polyvinyl Pyrrolidone (PVP), Carboxymethyl cellulose (CMC), Hydroxypropyl Cellulose (HPMC), regenerated cellulose, starch, polyethylene (PE), polypropylene (PP), polyacrylic acid, ethylene- It is at least one selected from the group consisting of propylene-diene monomer (ethylene propylene diene monomer, EPDM) and styrene butadiene rubber (SBR).

The conductive carbon as the conductive material is Super C, Ketjen Black, Carbon Nanotube, Super P, Acetylene Black, Denka Black, and Meso. One or more types selected from the group consisting of ordered mesoporous carbon and vapor-grown carbon nanofibers (VGCF).

Figure 2 is a flowchart showing a method of manufacturing a silicon anode with a three-dimensional porous structure.

According to Figure 2, a first step of preparing a slurry by mixing silicon, a pore former, conductive carbon, and a binder (S100), a second step of coating the slurry on a substrate to form a coating layer (S200), and the coating layer The process proceeds to the third step (S300) in which pores are formed by heat treatment.

According to the first step (S100), a slurry containing silicon, a pore former, conductive carbon, and a binder is prepared to manufacture a silicon anode. The slurry contains 10 wt% to 93 wt% of silicon relative to the total weight of the slurry, 1 wt% to 40 wt% of conductive carbon relative to the total weight of the slurry, and 1 wt% of the binder relative to the total weight of the slurry. wt% to 40 wt%, and the pore former is preferably included in 5 wt% to 80 wt% based on the total weight of the slurry. At this time, the binder is diluted with distilled water.

Silicon, which is a negative electrode active material, and a pore-forming agent are added simultaneously to the slurry, and the weight ratio of the silicon and the pore-forming agent is preferably 7:3 to 7:5. If the pore former compared to the silicon is less than 7:3, it is difficult to increase the electrochemical performance of the anode because sufficient pores are not created in the silicon anode, and if the pore former compared to the silicon is contained more than 7:5, the silicon anode is not sufficiently pore-forming. As the amount of active material decreases, electrical conductivity decreases and electrochemical performance may deteriorate.

The second step (S200) is a step of forming a coating layer by coating the slurry prepared in the first step (S100) on a substrate.

The third step (S300) is a step of forming pores by heat treating the substrate on which the coating layer was formed through the second step (S200). When the pore former included in the coating layer is heat treated at high temperature in an inert gas atmosphere, the pore former is decomposed and pores are formed in its place, thereby obtaining a silicon anode with a three-dimensional porous structure.

The heat treatment is preferably performed at a temperature of 200 ℃ to 800 ℃, and more preferably, the heat treatment is performed at a temperature of 400 ℃ to 800 ℃. If the temperature during heat treatment is less than 200 ℃, the pore former may not be removed. At a temperature of 800 ℃ or lower, the weight of the pore former becomes 0% and can be removed, so it is sufficient even if the temperature does not exceed 800 ℃.

Preparation Example 1: Preparation of pore forming agent

Figure 3 is a schematic diagram of equipment for synthesizing pore forming agents.

Referring to FIG. 3, the pore forming agent is added to the first reactor (60) by adding 2 g of polyvinylpyrrolidone (PVP) as a dispersant and 95 mL of ethanol as a solvent, and then using a magnetic stirrer (61) while raising the temperature to 70°C. The first mixture was created by mixing at a speed of 250 rpm. While the temperature of the mixture was rising, 0.1 g of initiator Azobisisobutyronitrile (AIBN) and 11 mL of styrene monomer were added to the second reactor 70 and then gently shaken for about 10 seconds to prepare a second mixture. When the temperature of the first reactor reached 70°C, the second mixture of the second reactor was added dropwise to the first mixture of the first reactor. The reaction proceeded for 24 hours while maintaining an argon gas atmosphere through the inert gas inlet 62 and operating the reflux cooler 63 using the water inlet 64 and water outlet 65. After time elapsed, the solution containing polystyrene and ethanol was centrifuged twice at 6000 rpm for 5 minutes each to settle precipitates containing unreacted styrene and impurities, and then dried in an oven to finally produce polystyrene with a size of 2 um. Particles were obtained.

The pore forming agent can be manufactured by adjusting the size depending on the amount of sample input. The particle size of the pore-forming agent increases as the concentration of the monomer, the initiator, or the ratio of the solvent increases. However, as the particle size increases, the uniformity of the generated particle size decreases. On the other hand, when the concentration of the dispersant is high, the particle size decreases and the uniformity of the particle size increases.

In the present invention, polystyrene particles of the target size were obtained by controlling the amount of ethanol. As the proportion of the ethanol solvent in the slurry phase increases, the particle size of the pore forming agent increases, and as the proportion of the ethanol solvent decreases, the particle size of the pore forming agent decreases.

Figure 4 is an SEM image of the pore former formed through Preparation Example 1.

Referring to FIG. 4, it can be seen from the SEM image that the spherical pore former is uniformly formed with a size of about 2 um.

Figure 5 is a graph showing the results of thermogravimetric analysis of the pore forming agent.

Referring to FIG. 5, the relative weight of the pore-forming agent rapidly decreases to 0% starting at about 400°C, so it can be seen that the pore-forming agent is removed when heated to a temperature of about 400°C or higher. Therefore, when manufacturing an electrode in the present invention, pores can be formed by performing heat treatment at a temperature of 400 ° C to 800 ° C.

Production example 2

In order to make a silicon anode with a three-dimensional porous structure, polystyrene, a pore forming agent, was prepared according to Preparation Example 1 above.

A slurry was prepared including polystyrene and silicon as pore formers prepared by the above method, conductive carbon Super C as a conductive material, and poly(amide imide) (PAI) as a binder. At this time, silicon, Super C, PAI, and polystyrene were added at a weight ratio of 7:1:2:4, and the diameter of polystyrene was 2 um. At this time, the PAI was diluted to 9.6 wt % using distilled water. The slurry was put into a kneader mixer (Non Bubbling Kneader NBK-1) containing zirconia balls, mixed at 1,200 rpm for 15 minutes, and then coated on a copper current collector to form a coating layer. The copper current collector on which the coating layer was formed was heated at a temperature of 450° C. for 1 hour under an argon atmosphere to obtain a silicon anode with a three-dimensional porous structure with a loading level of 0.93 mgcm ^-2 .

Comparative Example 1

A negative electrode was manufactured in the same manner as in Preparation Example 2, except that polystyrene, a pore forming agent, was not used. At this time, the PAI was diluted to 10 wt % using distilled water.

Comparative Example 2

A commercial circular lithium cathode foil (MTI Korea) with a thickness of 0.45 mm and a diameter of 16 mm was used as the cathode.

Comparative Example 3

It is composed of graphite, conductive carbon Super C as a conductive material, Styrene Butadiene Rubber (SBR) as a binder, and sodium Carboxy Methyl Cellulose (CMC) as a thickener at a weight ratio of 96:1:1.5:1.5. A slurry was prepared. At this time, SBR was diluted to 5 wt % using distilled water. The slurry was put into a kneader mixer (Non Bubbling Kneader NBK-1) containing zirconia balls, mixed at 1,200 rpm for 15 minutes, and then coated on a copper current collector to form a coating layer. The copper current collector on which the coating layer was formed was dried in a vacuum oven at 60° C. for 12 hours and then rolled to obtain a graphite anode with a loading level of 6.18 mgcm ^-2 .

Comparative Example 4

A negative electrode was manufactured in the same manner as in Preparation Example 2, except that the amount of ethanol was changed to 54 mL and 125 mL, respectively, to prepare polystyrene with a diameter of 1 um and 3 um. At this time, 1 um and 3 um polystyrene were added at a weight ratio of 1:5.

Comparative Example 5

A negative electrode was manufactured in the same manner as in Preparation Example 2, except that the weight ratio of silicon, Super C, PAI, and polystyrene was 7:1:2:8. At this time, the PAI was diluted to 9.2 wt % using distilled water.

Experimental Example 1

Figure 6 is an SEM image of Preparation Example 2 and Comparative Example 1. Figures 6 (a) and (c) are SEM images of Comparative Example 1, and no pores were observed because it was a pure silicon cathode without a pore-forming agent. On the other hand, Figures 6 (b) and (d) are SEM images of Preparation Example 1. Looking at (b), it can be observed that spherical pores of uniform size were formed. Also, looking at (d), it can be seen that pores are formed evenly.

Figure 7 is an SEM image of Comparative Example 4 and Comparative Example 5. Figures 7 (a) and (c) are SEM images of Comparative Example 4. Since pore forming agents with diameters of 1 um and 3 um were used, the size and distribution of pores were not uniform and had a perfectly spherical shape. It wasn't noticeable. Figures 7 (b) and (d) are SEM images of Comparative Example 5, which is a cathode formed at a weight ratio of silicon and pore former of 7:8, and the size of the formed pores is uniformly spherical, but on the cathode It was formed in an excessively dense manner.

Experimental Example 2

Figure 8 is a graph showing the results of a cycle performance test of the lithium ion capacitor containing Preparation Example 2 and Comparative Example 1.

The lithium ion capacitor was manufactured using a carbon anode and a 2032 coin cell.

The carbon anode was prepared as a slurry composed of activated carbon (MSC-30), Super C, and polyvinylidene fluoride (PVDF) at a weight ratio of 8:5:15, and the PVDF powder was mixed with N-Methyl, an organic solvent. It was used by dispersing it in -2-pyrrolidone (NMP) at 2.87 wt %. The slurry was put into a kneader mixer (Non Bubbling Kneader NBK-1) containing zirconia balls and mixed at 1,200 rpm for 15 minutes, then coated on aluminum foil to form a coating layer to form a carbon anode with a loading level of 3.5 mgcm ^-2 was obtained.

The lithium ion capacitor was assembled as a full cell inside a glove box in an argon atmosphere. At this time, the silicon cathode was used after assembling a half cell and performing activation and prelithiation before assembling the lithium ion capacitor. In the coin cell, a spring and a spacer are arranged in that order on the lower case, and an aluminum foil coated with the carbon anode is placed on the spacer. A coin cell was manufactured by placing a separator on the carbon anode, placing the cathodes of Preparation Example 1 and Preparation Example 3, and Comparative Example 1 and Comparative Example 3 on the separator, respectively, and assembling the upper case.

The cathode and positive electrode used to manufacture the coin cell have an active material weight ratio of 1:3.5 to 1:4.0, and the electrolyte inside the coin cell is EC (Ethylene Carbonate):DEC (Diethyl Carbonate) containing 1 M LiPF ₆ salt. (1:1, v/v) 200 uL was used.

Referring to FIG. 8, as a result of charging/discharging for 500 cycles under the condition of a current density of 1 mAcm ^-2 , Preparation Example 2 slightly decreased until 500 cycles, and the lifespan maintenance rate compared to the initial period was about 80%, and after 500 cycles, the lifespan maintenance rate was 196%. The capacity of mAhg ^-1 was maintained. In contrast, in Comparative Example 1, as the cycle was repeated, the capacity decreased significantly compared to the initial period, and the life maintenance rate was measured to be about 25.3%, and the capacity of 55 mAhg ^-1 was maintained after 500 cycles. Therefore, it can be seen that Preparation Example 2, in which pores are formed in the silicon anode, slows down cell deterioration due to charge/discharge.

Experimental Example 3

Figure 9 is a Ragone plot of the lithium ion capacitor including Preparation Example 2 and Comparative Examples 1 to 3. Preparation Example 2 and Comparative Examples 1 to 3 were performed for 5 cycles at a current density of 1 mAcm ^-2 , 2 mAcm ^-2 , 5 mAcm ^-2 , 10 mAcm ^-2 , and 20 mAcm ^{-2 ,} respectively, to produce a cell. The speed characteristics were compared.

Comparative Example 2 showed superior performance compared to Preparation Example 2, Comparative Example 1, and Comparative Example 3 at low current densities of 1 mAcm ^-2 and 2 mAcm ^-2 , but when the current density increased to 2 mAcm ^-2 or more, the capacity decreased. This decreased sharply. This is because Comparative Example 2 is a flat electrode and has a small reaction area, making high-speed charge/discharge difficult.

In Comparative Example 3, the decrease in capacity due to increase in current density was measured to be less than that in Preparation Example 2, Comparative Example 1, and Comparative Example 2. This is because the speed at which graphite moves internally is faster than that of silicon, and the reaction area of Comparative Example 3 is larger than that of Comparative Example 2 because Comparative Example 3 is arranged in three dimensions. However, because the theoretical capacity of graphite was smaller than that of silicon, the overall energy density was low.

Preparation Example 2 and Comparative Example 1 show a high energy density of 150 Whkg ^-1 at low current density. However, at high current densities, the energy density of Comparative Example 1 rapidly decreased due to the effects of volume change and mechanical stress. On the other hand, in Preparation Example 2, even at a high current density of 20 mAcm ^-2 , the effect of volume change and mechanical stress due to pores was small, suppressing electrode cracks, so efficiency did not decrease, and an excellent energy density of about 50 Whkg ^-1 was observed. It has been done.

Experimental Example 4

Figure 10 is a graph of half-cell test results for cycles according to discharge capacity of Preparation Example 2, Comparative Example 4, and Comparative Example 5. The half cell used in the experiment has a spring, a spacer, and a lithium metal electrode arranged in that order on the lower case, a separator is placed on the lithium metal electrode, and Preparation Example 2, Comparative Example 4, and Comparative Example 5 was placed and the upper case was placed to assemble the cell and then used in the experiment. The above experiment is the result of charging/discharging at a current density of 2A/g _si . Preparation Example 2, which contains a pore former of 2 um and has a weight ratio of silicon and pore former of 7:4, has a shorter cycle time than Comparative Example 4, which has a different size of the pore former, and Comparative Example 5, which has a different weight ratio. As it repeats, the discharge capacity gradually decreases. In Comparative Example 4, the initial capacity was measured to be higher than that of Preparation Example 2 because pores of various sizes were formed, but the capacity dropped sharply after about 20 cycles, so the cell performance was not excellent. Comparative Example 5 draws a graph in which the initial capacity is similar to Preparation Example 2 and the capacity is maintained, but the capacity rapidly decreases after about 70 cycles. This can be seen as a decrease in capacity because the pore-forming agent was added in excess compared to silicon, and the reaction was not smooth due to a lack of active material in the electrode. Therefore, it is most desirable to manufacture the cell under the conditions of Production Example 2.

In the present invention, in a negative electrode having a three-dimensional porous structure, a pore-forming agent is included during slurry production, so that the electrode active material and the pore-forming agent are applied simultaneously. Therefore, the electrode manufacturing process is simple and manufacturing costs can be reduced. In addition, by forming an electrode with a three-dimensional porous structure, the output characteristics can be improved by increasing the reaction area compared to electrodes with a flat structure and electrodes without pores. In addition, due to the presence of pores, the influence of volume change and mechanical stress is small, so electrode cracks are not easily formed, ensuring long-term stability and increasing cycle life.

10: base material 20: silicone
30: pore former 40: conductive carbon
50: Binder 51: Pores
60: First reactor 61: Magnetic stirrer
62: inert gas inlet 63: reflux cooler
64: water inlet 65: water outlet
70: second reactor

Claims (14)

write; and
A silicon anode with a three-dimensional porous structure comprising a coating layer applied on the substrate, wherein the coating layer includes pores therein after heat treatment of the slurry applied on the substrate. According to paragraph 1,
The slurry is a silicon anode with a three-dimensional porous structure, characterized in that it is composed of silicon, a pore former, conductive carbon, and a binder. According to paragraph 2,
The pore forming agent is a three-dimensional porosity, characterized in that at least one selected from the group consisting of polystyrene, polymethylmethacrylate, polyvinylpyrrolidone, and polytetrafluoroethylene. Structure of silicon cathode. According to paragraph 2,
A silicon anode with a three-dimensional porous structure, wherein the pore forming agent has a spherical shape. According to paragraph 2,
A silicon anode with a three-dimensional porous structure, wherein the pore forming agent has a size of 100 nm to 10 um. According to paragraph 2,
The slurry is a silicon anode with a three-dimensional porous structure, characterized in that the silicon and the pore former are contained in a weight ratio of 7:3 to 7:5. According to paragraph 2,
The binder is polyimide, poly(amide imide) (PAI), polyvinylidene fluoride (PVDF), vinylidene fluoride/hexafluoropropylene copolymer (Hexafluoropropylenevinylidenefluoride copolymer) , Polyacrylonitrile (PAN), Poly (methyl methacrylate), PMMA), Polytetrafluoroethylene (PTFE), Polyvinyl Pyrrolidone (PVP), Carboxymethyl cellulose (CMC), Hydroxypropyl Cellulose (HPMC), regenerated cellulose, starch, polyethylene (PE), polypropylene (PP), polyacrylic acid, ethylene- A silicon anode with a three-dimensional porous structure comprising at least one selected from the group consisting of propylene-diene monomer (ethylene propylene diene monomer, EPDM) and styrene butadiene rubber (SBR). Preparing a slurry by mixing silicon, a pore former, conductive carbon as a conductive material, and a binder;
Forming a coating layer by coating the slurry on a substrate; and
A method of manufacturing a silicon anode with a three-dimensional porous structure, comprising: heat-treating the coating layer to remove the pore-forming agent to form pores within the electrode. According to clause 8,
The slurry contains 10 wt% to 93 wt% of silicon relative to the total weight of the slurry, 1 wt% to 40 wt% of conductive carbon relative to the total weight of the slurry, and 1 wt% of the binder relative to the total weight of the slurry. wt% to 40 wt%, and the pore former is 5 wt% to 80 wt% based on the total weight of the slurry. According to clause 8,
A method of manufacturing a silicon anode with a three-dimensional porous structure, characterized in that the slurry contains the silicon and the pore former in a weight ratio of 7:3 to 7:5. According to clause 8,
A method of manufacturing a silicon anode with a three-dimensional porous structure, characterized in that the heat treatment is performed at a temperature of 200 ℃ to 800 ℃. According to clause 8,
The pore forming agent,
Generating a first mixture by adding a dispersant and a solvent to a first reactor;
setting the temperature of the first reactor and stirring the first mixture;
adding an initiator and a monomer to a second reactor to produce a second mixture;
forming a reactant by dropping the second mixture drop by drop when the temperature of the first reactor reaches the target; and
A method of manufacturing a silicon anode with a three-dimensional porous structure, comprising the step of removing and drying impurities in the reactant. According to clause 8,
A method of manufacturing a silicon anode with a three-dimensional porous structure, characterized in that the pore forming agent is applied on the substrate simultaneously with the silicon. According to clause 8,
The pore forming agent has a spherical shape and is at least one selected from the group consisting of polystyrene, polymethylmethacrylate, polyvinylpyrrolidone, and polytetrafluoroethylene. A method of manufacturing a silicon anode with a three-dimensional porous structure.