High-performance silicon-based composite anode material coated with conductive polymer and graphene or reduced graphene oxide, and manufacturing method thereof

Abstract

To provide a high-performance silicon-based composite anode material that can exhibit high performance such as high capacity, high efficiency, high-speed charging, and high stability, which suppresses expansion, and a method for manufacturing the same.SOLUTION: There is provided a high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide, which is then coated with graphene or reduced graphene oxide after coating the silicon-based powder with a conductive polymer to stabilize the silicon-based powder and suppress expansion during charging and discharging, or by simultaneously coating the silicon-based powder with a conductive polymer and graphene or reduced graphene oxide, thereby improving the adhesion of graphene and the stability of silicon, and there is also provided a manufacturing method thereof.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide, and a manufacturing method thereof. More specifically, the present invention relates to a high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide, which can exhibit high performance in suppressing expansion, such as high capacity, high efficiency, fast charging, and high stability, by coating a silicon-based powder with a conductive polymer and then coating it with graphene or reduced graphene oxide, or by simultaneously coating a silicon-based powder with a conductive polymer and graphene or reduced graphene oxide, thereby improving the adhesion of graphene and the stability of silicon, and by suppressing expansion, and a manufacturing method thereof. [Background technology]

[0002] The proliferation of social demands such as portable electronic devices, power tools, and electric vehicles has increased the need for high-performance secondary batteries. In particular, the emergence of electric vehicles has created a demand for fast-charging lithium-ion batteries with high electrical capacity and low weight.

[0003] Currently, commercially available graphite powders are the main raw material for lithium-ion battery anode materials, but they have low maximum capacity and slow charge / discharge speeds, meaning they cannot meet the essential requirements of the battery market, which require high capacity and high performance. Therefore, there is an urgent need to develop new anode materials that can meet these requirements.

[0004] To increase the charging capacity and speed up charging of secondary batteries, silicon anode materials, which have a capacity per unit weight that is more than 10 times higher than that of existing graphite anode materials, can be used instead of graphite-based materials, allowing the thickness of the electrode to be reduced and more lithium ions to be stored and released more quickly.As a result, the use of silicon anode materials can increase driving distance and speed up charging, and in recent years, attempts to use silicon anode materials as an alternative and research into adding silicon to existing graphite anode materials are being conducted competitively both domestically and internationally.

[0005] However, in the case of silicon anode materials, when lithium moves from the positive electrode to the negative electrode, it reacts with silicon, causing a volume expansion of approximately 400%, which leads to cracking of the silicon powder, and repeated charge and discharge causes the silicon powder to pulverize. This causes the electrode to structurally deform and lose its function as an electrode, or the solid electrolyte interphase (SEI) peels off and a heterogeneous interface is created, requiring the consumption of more lithium ions and significantly reducing efficiency.

[0006] As a result of the above, lithium-ion batteries are experiencing serious performance degradation (reduction in initial energy capacity when repeatedly charged and discharged) and shortened lifespan, delaying their practical commercial application.

[0007] To address these issues, current attempts have been made to use nanostructured silicon, such as nanopowder, nanowires, and various nanoporous materials. However, most nanostructured silicon manufacturing methods involve expensive, high-temperature chemical vapor deposition, a complex series of chemical reactions, or templates, which are incompatible with existing battery manufacturing methods and cannot be scaled up for mass production. Furthermore, the cost of nanomaterials is about 10 times higher than that of micron-sized silicon, making practical application difficult.

[0008] Current methods for using silicon-based materials include the use of SiOx composite oxides, SiC, or silicon alloys. However, they suffer from drawbacks such as low initial capacity, non-uniformity, poor conductivity due to insulating properties, reduced electrochemical performance, and high material costs. Another approach involves adding a small amount of silicon to existing graphite-based anode materials to improve stability and capacity, but the limited silicon content of less than 10 wt% and the high process costs are obstacles to commercialization.

[0009] In recent years, a method of coating or wrapping silicon with graphene to reduce volume expansion and increase conductivity has been gaining attention. However, due to the weak adhesive strength between graphene and silicon, the two materials are attached and detached as charging and discharging occur, so the actual effect is limited.

[0010] In addition, all of the currently proposed solutions are effective only when applied to expensive nanosilicon powder having a uniform shape and a size of about 100 nm or less, and there have been no successful cases of applying them to relatively inexpensive, irregularly shaped micron-sized silicon.

[0011] A related prior art document is Korean Patent Publication No. 10-2023-0154397 (published on November 8, 2023), which describes a composite negative electrode material of nano-silicon aggregates and a method for manufacturing the same. Summary of the Invention [Problem to be solved by the invention]

[0012] An object of the present invention is to provide a high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide, which can exhibit high performance in terms of suppressing expansion, such as high capacity, high efficiency, fast charging, and high stability, by coating a silicon-based powder with a conductive polymer and then coating it with graphene or reduced graphene oxide, or by simultaneously coating a silicon-based powder with a conductive polymer and graphene or reduced graphene oxide, thereby improving the adhesion of graphene and the stability of silicon, and thereby providing a method for producing the same. [Means for solving the problem]

[0013] To achieve the above object, a method for manufacturing a high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide according to an embodiment of the present invention includes: a surface treatment step of surface-treating a silicon-based powder; a composite solution preparation step of coating the surface-treated silicon-based powder with a conductive polymer and then compositing it with graphene or reduced graphene oxide, or simultaneously compositing the conductive polymer and graphene or reduced graphene oxide on the surface-treated silicon-based powder, thereby manufacturing a silicon-based composite solution; and a composite powder preparation step of washing, filtering, and drying the silicon-based composite solution, thereby manufacturing a silicon-based composite anode material.

[0014] The surface treatment step includes a surface modification process for forming hydroxyl radicals on the surface of the silicon-based powder.

[0015] The silicon-based powder includes at least one selected from the group consisting of pure Si (pure Si), SiOx (0.5≦x≦1.5), SiC, and Si alloys, each having an average diameter of 1 nm to 100 μm.

[0016] The conductive polymer includes at least one selected from the group consisting of polypyrrol, polythiophene, polyacetylene, polyaniline, poly(3,4-ethylenedioxythiophene), PEDOT:PSS, polyparaphenylene, and polyparaphenylene vinylene.

[0017] The graphene is graphene or reduced graphene oxide having 1 to 6 layers and an average diameter of 1 to 10 μm.

[0018] The composite solution is prepared by adding the conductive polymer to a solution of the silicon-based powder that has been put into distilled water and surface-treated, and then stirring to prepare a silicon-based powder-conductive polymer composite solution, and then mixing the graphene or reduced graphene oxide into the silicon-based powder-conductive polymer composite solution to react with it.

[0019] The composite solution is prepared by simultaneously adding the conductive polymer and the graphene or reduced graphene oxide to a solution of the silicon-based powder that has been surface-treated in distilled water, and stirring the mixture to react.

[0020] The filtering, washing, and drying steps are performed by filtering the silicon-based powder-conductive polymer-graphene composite solution to remove the solvent, washing with purified distilled water to remove impurities, excess ions, and oligomers adsorbed on the surface of the silicon-based composite powder, and then drying to remove residual moisture, thereby coating the surface of the silicon-based powder with the conductive polymer and graphene or reduced graphene oxide to form a structure that stably wraps the surface of the silicon-based powder.

[0021] The silicon-based composite powder includes a silicon-based powder located at an internal center, graphene or reduced graphene oxide coated to surround the silicon-based powder, and a conductive polymer disposed in a space between the silicon-based powder and the graphene or reduced graphene oxide and coated to surround the silicon-based powder.

[0022] The silicon-based composite powder includes a silicon-based powder located at the center and a mixed composite coating the silicon-based powder. The mixed composite includes a conductive polymer and graphene, and the graphene is graphene or reduced graphene oxide having 1 to 6 layers and an average diameter of 1 to 10 μm.

[0023] To achieve the above object, according to one embodiment of the present invention, there is provided a high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide, the anode material including: a silicon-based powder located at a center portion thereof; graphene or reduced graphene oxide coated to surround the silicon-based powder; and a conductive polymer disposed in a space between the silicon-based powder and the graphene or reduced graphene oxide, the conductive polymer being coated to surround the silicon-based powder.

[0024] To achieve the above object, according to another embodiment of the present invention, there is provided a high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide, which comprises a silicon-based powder located at an internal center and a mixed composite coated to surround the silicon-based powder, wherein the mixed composite comprises a conductive polymer and graphene, and the graphene is graphene or reduced graphene oxide having 1 to 6 layers and an average diameter of 1 to 10 μm. [Effects of the Invention]

[0025] The high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide, and its manufacturing method, according to the present invention, form a structure in which the surface of a silicon-based powder is coated and wrapped with a conductive polymer and graphene or reduced graphene oxide, thereby increasing the conductivity of the silicon-based composite anode material, enhancing the adhesiveness of graphene, and achieving maximum suppression of volume expansion of the silicon-based composite anode material during charge and discharge, while maintaining electrode properties even when the silicon-based powder is pulverized.

[0026] As a result, the high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide according to the present invention, and its manufacturing method, can not only induce long-term battery stability, but also maximize the effect when the size of the silicon-based powder is not limited to nano-size but is as large as micron-size, or is not spherical but has an irregular shape.

[0027] As described above, the high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide according to the present invention, and its manufacturing method, can increase the conductivity of the silicon-based composite anode material, inhibit volume expansion of the silicon-based composite anode material during charging and discharging, and maintain electrode properties even when the powder is pulverized, thereby not only inducing long-term battery stability but also maximizing the effects of the high-capacity silicon-based composite anode material regardless of the size or shape of the silicon-based powder, and completely replacing existing graphite-based anode materials that have disadvantages of low capacity and slow charging, and current nanosilicon anode materials that are expensive and uncertain in terms of mass production and applicability.

[0028] As a result, the high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide according to the present invention, and its manufacturing method, provide an ideal silicon-based composite anode material with high capacity, high efficiency, fast charging, and high stability, and can be perfectly applied to the anode of high-performance secondary batteries, thereby making a significant contribution to the development and commercialization of the battery industry. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a process flow diagram illustrating a method for manufacturing a high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide according to an embodiment of the present invention. [Figure 2] 1 is a process diagram illustrating a method for manufacturing a high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide according to an embodiment of the present invention. [Figure 3] FIG. 1 is a schematic diagram illustrating a high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide, prepared by a method according to an embodiment of the present invention. [Figure 4] 1 is a transmission electron microscope (TEM) photograph showing the state of the silicon-based composite negative electrode material prepared according to Example 1 before charging and discharging. [Figure 5] 1 is a transmission electron microscope (TEM) photograph showing the state of the silicon-based composite negative electrode material prepared according to Example 1 after charging and discharging. [Figure 6] 1 is a graph showing the results of measuring the cycle characteristics of charge and discharge capacities of a half coin cell using pure silicon powder according to Comparative Example 1 as a silicon-based negative electrode material and a half coin cell using a silicon powder-conductive polymer-graphene composite powder according to Example 1 as a silicon-based composite negative electrode material. DETAILED DESCRIPTION OF THE INVENTION

[0030] The advantages and features of the present invention, as well as methods for achieving them, will become clearer with reference to the following detailed examples in conjunction with the accompanying drawings. However, the present invention is not limited to the examples disclosed below, and may be embodied in various different forms. However, these examples are provided to complete the disclosure of the present invention and to fully convey the scope of the invention to those skilled in the art to which the present invention pertains, and the present invention is defined only by the scope of the claims. The same reference symbols throughout the specification refer to the same elements.

[0031] Hereinafter, a high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide, and a manufacturing method thereof, according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0032] FIG. 1 is a process flow diagram illustrating a method for manufacturing a high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide according to an embodiment of the present invention. FIG. 2 is a process schematic diagram illustrating a method for manufacturing a high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide according to an embodiment of the present invention. FIG. 3 is a schematic diagram illustrating a high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide manufactured by a method according to an embodiment of the present invention.

[0033] Referring to FIGS. 1 to 3, a method for manufacturing a high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide according to an embodiment of the present invention includes a step of surface treating a silicon-based powder (S110), a step of preparing a composite solution (S120), and a step of preparing a composite powder (S130).

[0034] Surface treatment of silicon powder In the step of surface treating the silicon-based powder (S110), the silicon-based powder is surface treated.

[0035] Here, the silicon-based powder includes at least one selected from the group consisting of pure Si (pure Si), SiOx (0.5≦x≦1.5), SiC, and Si alloys, each having an average diameter of 1 nm to 100 μm.

[0036] These silicon-based powders preferably have an average diameter of 1 nm to 100 μm, more preferably 100 nm to 50 μm, and most preferably 1 to 30 μm. If the average diameter of the silicon-based powder is less than 1 nm, there is a problem that the charging and discharging of lithium ions is not carried out in sufficient amounts. Conversely, if the average particle diameter of the silicon-based powder exceeds 100 μm, the silicon-based powder may be prone to cracking due to continuous charging and discharging of lithium ions, which is undesirable.

[0037] In the surface treatment step (S110) of these silicon-based powders, the conductive polymer is uniformly coated on the silicon-based powder, and the surface treatment is performed to form hydroxyl radicals (-OH) on the surface of the silicon-based powder in order to enhance adhesion between the silicon-based powder, the conductive polymer, and the graphene.

[0038] Thus, the surface treatment step (S110) of the silicon-based powder includes a surface modification process for forming hydroxyl radicals on the surface of the silicon-based powder.

[0039] The surface treatment step (S110) of the silicon-based powder will be described in more detail below.

[0040] First, the silicon-based powder is weighed out and mixed with distilled water, followed by stirring with a stirrer. Next, a reactive additive (dopant) that can form hydroxyl groups on the surface of the silicon-based powder, such as phytic acid or formic acid, and a reagent that acts as a cross-linker are weighed out and added, followed by stirring. Next, a small amount of initiator or partial oxidizing agent is added to increase the conductivity of the conductive polymer, and the mixture is stirred.

[0041] Preparation of complex solutions In the step of preparing a composite solution (S120), a conductive polymer is coated on the surface-treated silicon-based powder, and then the conductive polymer is composited with graphene or reduced graphene oxide, or the conductive polymer and graphene or reduced graphene oxide are simultaneously composited with the surface-treated silicon-based powder to prepare a silicon-based composite solution.

[0042] In the step of preparing a solution of these composites (S120), it is preferable to weigh out the surface-treated silicon-based powder and graphene or reduced graphene oxide according to the mixing ratio, and then mix and stir them.

[0043] In this case, the conductive polymer includes at least one selected from the group consisting of polypyrrol, polythiophene, polyacetylene, polyaniline, poly(3,4-ethylenedioxythiophene), PEDOT:PSS, polyparaphenylene, and polyparaphenylene vinylene.

[0044] In this stage, stirring is preferably carried out at a speed of 200 to 600 rpm, more preferably 300 to 500 rpm. If the stirring speed is less than 200 rpm, there is a risk of uniform mixing being impossible due to viscosity imbalance between the silicon-based powder, the conductive polymer, and the graphene. Conversely, high-speed stirring at a speed exceeding 600 rpm can actually reduce uniformity, so caution is required.

[0045] The preparation of these composite solutions (S121) involves adding a conductive polymer to a surface-treated silicon-based powder solution in distilled water, stirring the mixture to produce a silicon-based powder-conductive polymer composite solution, and then mixing graphene or reduced graphene oxide into the silicon-based powder-conductive polymer composite solution to allow the reaction to occur.

[0046] Alternatively, the preparation of the composite solution (S122) can be performed by simultaneously adding the conductive polymer and graphene or reduced graphene oxide to a surface-treated silicon-based powder solution in distilled water, and then stirring the mixture to react.

[0047] Production of composite powder In the composite powder preparation step (S130), the silicon-based composite solution is washed, filtered and dried to prepare a silicon-based composite negative electrode material.

[0048] In this step, the filtering, washing, and drying are carried out by filtering the solution of the silicon-based powder-conductive polymer-graphene composite to remove the solvent, washing with purified distilled water to remove impurities, excess ions, and oligomers adsorbed on the surface of the silicon-based composite powder, and then drying to remove residual moisture, thereby coating the surface of the silicon-based powder with the conductive polymer and graphene or reduced graphene oxide to form a structure that stably encases the surface of the silicon-based powder.

[0049] Drying is preferably carried out at 60 to 120°C for 3 to 12 hours, and more preferably at 80 to 100°C for 5 to 10 hours. If the drying temperature is below 60°C or the drying time is less than 3 hours, residual moisture may not be completely removed. Conversely, if the drying temperature exceeds 120°C or the drying time exceeds 12 hours, excessive heat energy and time may be consumed, which is uneconomical.

[0050] In this step, the silicon-based composite powder may include a silicon-based powder located at the inner center, graphene or reduced graphene oxide coated to surround the silicon-based powder, and a conductive polymer disposed in a space between the silicon-based powder and the graphene or reduced graphene oxide and coated to surround the silicon-based powder.

[0051] In this case, the conductive polymer is preferably formed as a layer having a thickness of 10 nm to 1 μm, and more preferably 30 to 500 nm depending on the size of the silicon-based powder. If the thickness of the conductive polymer layer is less than 10 nm, it is difficult to effectively improve conductivity. Conversely, if the thickness of the conductive polymer layer exceeds 1 μm, the process time may be lengthened and the coating uniformity may be reduced, rather than further improving the properties.

[0052] Furthermore, the graphene or reduced graphene oxide is preferably formed as a layer having a thickness of 1 to 100 nm, more preferably 5 to 50 nm. If the thickness of the graphene or reduced graphene oxide layer is less than 1 nm, it may not be possible to effectively suppress the volume expansion of the silicon-based composite negative electrode material during charge and discharge. Conversely, if the thickness of the graphene or reduced graphene oxide layer exceeds 100 nm, the adhesion between the silicon-based powder and the conductive polymer and graphene may be reduced.

[0053] Alternatively, the silicon-based composite powder may include a silicon-based powder located at the center and a mixed composite coating the silicon-based powder. The mixed composite may include a conductive polymer and graphene, and the graphene may be graphene or reduced graphene oxide having 1 to 6 layers and an average diameter of 1 to 10 μm.

[0054] In this case, the mixed composite is preferably formed as a layer having a thickness of 10 nm to 1 μm, and more preferably as a layer having a thickness of 30 to 500 nm. If the mixed composite layer is less than 10 nm thick, it may not be able to effectively suppress the volume expansion of the silicon-based composite anode material during charge and discharge. Conversely, if the mixed composite layer is more than 1 μm thick, it may result in longer processing time and reduced coating uniformity, rather than further improving performance.

[0055] In this way, silicon-based composite anode materials coated with a conductive polymer and graphene or reduced graphene oxide have excellent adhesive strength between the materials, suppress the expansion of silicon powder during charge and discharge, and maintain electrode properties even when pulverized. Because they are effective anode materials regardless of the size or shape of the silicon-based powder, when applied to secondary batteries, they exhibit high capacity, fast charging, and stable charge and discharge cycle characteristics.

[0056] Furthermore, the manufacturing method of the present invention is simple, suitable for existing battery processes, and allows for mass production at low production costs. Therefore, by providing a method for manufacturing ideal high-performance anode materials, it is expected to have a significant impact on the development and commercialization of the battery industry.

[0057] As discussed above, the high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide according to the embodiments of the present invention and its manufacturing method form a structure in which the surface of a silicon-based powder is coated and wrapped with a conductive polymer and graphene or reduced graphene oxide, thereby increasing the conductivity of the silicon-based composite anode material, enhancing the adhesiveness of graphene, and achieving maximum suppression of volumetric expansion of the silicon-based composite anode material during charge and discharge, while maintaining electrode properties even when the silicon-based powder is pulverized.

[0058] As a result, the high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide according to the embodiment of the present invention, and the manufacturing method thereof, can not only induce long-term stability of the battery, but also maximize the effect when the size of the silicon-based powder is not limited to nano-size but is as large as micron-size, or is not spherical but has an irregular shape.

[0059] As described above, the high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide according to the embodiments of the present invention, and the manufacturing method thereof, can increase the conductivity of the silicon-based composite anode material, suppress volume expansion of the silicon-based composite anode material due to charge and discharge, and maintain electrode properties even when the powder is pulverized, thereby not only inducing long-term battery stability but also maximizing the effects of the high-capacity silicon-based composite anode material regardless of the size or shape of the silicon-based powder, and completely replacing existing graphite-based anode materials that have disadvantages of low capacity and slow charging, and current nanosilicon anode materials that are expensive and uncertain in terms of mass production and applicability.

[0060] As a result, the high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide according to the embodiments of the present invention, and the manufacturing method thereof, provide an ideal silicon-based composite anode material with high capacity, high efficiency, fast charging, and high stability, and can be perfectly applied to the anode of high-performance secondary batteries, thereby making a significant contribution to the development and commercialization of the battery industry.

[0061] Example The following provides a more detailed explanation of the structure and operation of the present invention by way of preferred examples, which are presented as preferred examples of the present invention and are not to be construed as limiting the present invention in any way.

[0062] The contents not described here will not be explained here because they can be fully inferred by those skilled in the art.

[0063] 1. Sample Preparation Example 1 Purity (>99%) and particle size (D 50 30 g of pure silicon powder (particle size = 2 μm) was mixed with 100 ml of distilled water and stirred at a stirring speed of 500 rpm.

[0064] Next, 10 g of phytic acid was further added, and stirring was carried out at a speed of 500 rpm.

[0065] Next, 3 g of aniline, which is a conductive polymer, was added to the stirred mixed solution, and then 0.5 g of ammonium persulfate was added to carry out a reaction.

[0066] Next, 0.9 g of graphene powder was further added, and then the coating process was carried out at a stirring speed of 400 rpm to prepare a composite solution.

[0067] Next, the composite solution was washed with distilled water and filtered using a 5 μm qualitative filter paper to remove the solvent and impurities. After that, it was dried in a drying oven at 110°C for 7 hours to produce a powdered silicon-based composite anode material in which the surface of the silicon powder was sequentially coated with a conductive polymer and graphene.

[0068] Comparative Example 1 Purity (>99%) and particle size (D 50 Pure silicon powder (fine particle size = 2 μm) was prepared.

[0069] 2. Observation of microstructure FIG. 4 is a transmission electron microscope (TEM) photograph showing the state of the silicon-based composite anode material prepared according to Example 1 before charging and discharging, and FIG. 5 is a transmission electron microscope (TEM) photograph showing the state of the silicon-based composite anode material prepared according to Example 1 after charging and discharging.

[0070] As shown in Figures 4 and 5, the silicon-based composite anode material prepared according to Example 1 was observed using a transmission electron microscope, and it was confirmed that even when silicon pulverization occurred, the coating structure was not lost and the coated conductive polymer and graphene successfully enveloped and protected the silicon powder. As such, it was confirmed that the silicon-based composite anode material prepared according to Example 1 has a structure in which the silicon powder is coated with the conductive polymer and graphene, uniformly enveloping the periphery.

[0071] 3. Evaluation of Electrochemical Properties FIG. 6 is a graph showing the results of measuring the charge / discharge capacity cycle characteristics of a half coin cell using the pure silicon powder according to Comparative Example 1 as a silicon-based negative electrode material and a half coin cell using the silicon powder-conductive polymer-graphene composite powder according to Example 1 as a silicon-based composite negative electrode material.

[0072] As shown in FIG. 6, after 100 charge-discharge cycles, the remaining capacity was only about 15% of that when the uncoated pure silicon powder according to Comparative Example 1 was used as the silicon-based anode material.

[0073] On the other hand, when the silicon powder-conductive polymer-graphene composite powder according to Example 1, in which the conductive polymer and graphene are uniformly coated, is used as a silicon-based composite anode material, it is confirmed that a high capacity of 1600 mAh / g or more and a residual capacity of 90% or more are maintained even after 100 charge / discharge cycles.

[0074] As can be seen from the above experimental results, it is possible to manufacture a high-performance secondary battery anode material that has high capacity and can maintain stable cycle life characteristics by using the resultant product of the present invention. Furthermore, since the manufacturing method allows for a series of uniform coatings through a simple mixing and reaction process, it is easy to mass-produce and manufacture a high-performance secondary battery anode at an efficient cost, and it has been confirmed that mass productivity and commercialization can be ensured.

[0075] Although the present invention has been described above with reference to its preferred embodiments, various modifications and variations may be made by those skilled in the art. These modifications and variations are within the scope of the present invention as long as they do not deviate from the scope of the technical concept provided by the present invention. Therefore, the scope of the present invention should be determined by the following claims. [Explanation of symbols]

[0076] S110 Surface treatment stage of silicon powder S120 Complex solution preparation stage S130 Composite powder manufacturing stage

Claims

1. a surface treatment step of surface-treating the silicon-based powder; a step of preparing a silicon-based composite solution by coating the surface-treated silicon-based powder with a conductive polymer and then compositing the conductive polymer with graphene or reduced graphene oxide, or by simultaneously compositing the conductive polymer and graphene or reduced graphene oxide on the surface-treated silicon-based powder; and a step of preparing a powder of the silicon-based composite by washing, filtering, and drying the silicon-based composite solution to prepare a silicon-based composite negative electrode material; characterized in that it comprises A method for manufacturing high-performance silicon-based composite anode materials coated with conductive polymer and graphene or reduced graphene oxide.

2. The surface treatment step includes: The method includes a surface modification process for forming hydroxyl radicals on the surface of the silicon-based powder. A method for producing a high-performance silicon-based composite negative electrode material coated with the conductive polymer of claim 1 and graphene or reduced graphene oxide.

3. The silicon-based powder is The present invention is characterized in that the material contains at least one selected from the group consisting of pure Si (pure Si), SiOx (0.5≦x≦1.5), SiC, and Si alloys having an average diameter of 1 nm to 100 μm. A method for producing a high-performance silicon-based composite negative electrode material coated with the conductive polymer of claim 1 and graphene or reduced graphene oxide.

4. The conductive polymer is The polymerizable composition includes at least one polymer selected from the group consisting of polypyrrol, polythiophene, polyacetylene, polyaniline, poly(3,4-ethylenedioxythiophene), PEDOT:PSS, polyparaphenylene, and polyparaphenylene vinylene. A method for producing a high-performance silicon-based composite negative electrode material coated with the conductive polymer of claim 1 and graphene or reduced graphene oxide.

5. The graphene is Graphene or reduced graphene oxide having 1 to 6 layers and an average diameter of 1 to 10 μm, A method for producing a high-performance silicon-based composite negative electrode material coated with the conductive polymer of claim 1 and graphene or reduced graphene oxide.

6. The preparation of the solution of the complex comprises: The conductive polymer is added to the silicon-based powder solution that has been surface-treated in distilled water, and the mixture is stirred to produce a silicon-based powder-conductive polymer composite solution. The graphene or reduced graphene oxide is mixed with the silicon-based powder-conductive polymer composite solution and reacted with the silicon-based powder-conductive polymer composite solution. A method for producing a high-performance silicon-based composite negative electrode material coated with the conductive polymer of claim 1 and graphene or reduced graphene oxide.

7. The preparation of the solution of the complex comprises: The conductive polymer and the graphene or reduced graphene oxide are simultaneously added to the silicon-based powder solution that has been put into distilled water and surface-treated, and the mixture is stirred to react with each other. A method for producing a high-performance silicon-based composite negative electrode material coated with the conductive polymer of claim 1 and graphene or reduced graphene oxide.

8. The above filtering, washing and drying are carried out by The silicon-based powder-conductive polymer-graphene composite solution is filtered to remove the solvent, washed with purified distilled water to remove impurities, excess ions, and oligomers adsorbed on the surface of the silicon-based composite powder, and then dried to remove residual moisture, thereby coating the surface of the silicon-based powder with the conductive polymer and graphene or reduced graphene oxide to form a structure that stably encases the surface of the silicon-based powder. A method for producing a high-performance silicon-based composite negative electrode material coated with the conductive polymer of claim 1 and graphene or reduced graphene oxide.

9. The silicon-based composite powder is the silicon-based powder is located at the center of the silicon-based powder; graphene or reduced graphene oxide is coated to surround the silicon-based powder; and a conductive polymer is disposed in a space between the silicon-based powder and the graphene or reduced graphene oxide and coated to surround the silicon-based powder. A method for producing a high-performance silicon-based composite negative electrode material coated with the conductive polymer of claim 1 and graphene or reduced graphene oxide.

10. The silicon-based composite powder is The composite material includes a silicon-based powder located at a center thereof, and a mixed composite coated on the silicon-based powder, the mixed composite including a conductive polymer and graphene, the graphene being graphene or reduced graphene oxide having 1 to 6 layers and an average diameter of 1 to 10 μm. A method for producing a high-performance silicon-based composite negative electrode material coated with the conductive polymer of claim 1 and graphene or reduced graphene oxide.

11. A high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide, the anode material being manufactured by the method according to any one of claims 1 to 10, The silicon-based composite negative electrode material is Silicon-based powder located in the inner core; Graphene or reduced graphene oxide coated in a form that surrounds the silicon-based powder; and a conductive polymer disposed in a space between the silicon-based powder and the graphene or reduced graphene oxide, and coated to encase the silicon-based powder; characterized in that it comprises A high-performance silicon-based composite anode material coated with conductive polymer and graphene or reduced graphene oxide.

12. A high-performance silicon-based composite anode material coated with a conductive polymer and graphene or reduced graphene oxide, the anode material being manufactured by the method according to any one of claims 1 to 10, The silicon-based composite negative electrode material is Silicon powder located at the center of the interior, a mixed composite coated in a form that surrounds the silicon-based powder, The mixed composite includes a conductive polymer and graphene, The graphene is characterized in that it is graphene or reduced graphene oxide having 1 to 6 layers and an average diameter of 1 to 10 μm. A high-performance silicon-based composite anode material coated with conductive polymer and graphene or reduced graphene oxide.

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