Preparation method and apparatus for nano-silicon powder

Abstract

This application provides a method and apparatus for preparing nano-silicon powder. The method includes: placing purified silicon in a vacuum chamber and heating it to a first preset temperature to activate it; introducing hydrogen gas into the vacuum chamber; decomposing the hydrogen gas at a second preheating temperature to generate hydrogen atoms; reacting the hydrogen atoms with the activated purified silicon to obtain silane; subjecting the silane to a pyrolysis reaction at a third preset temperature to obtain a nano-silicon powder precursor; and post-processing the nano-silicon powder precursor to obtain stable and high-performance nano-silicon powder. By using purified silicon and hydrogen gas as the initial reactants, and utilizing the decomposition of hydrogen gas into hydrogen atoms to react with activated silicon to generate silane, compared with the traditional magnesium silicide method or chlorosilane reduction method, the reaction path is more direct, with fewer byproducts, significantly improving the purity of nano-silicon powder. It also avoids the transportation and storage of silane gas, thus fundamentally solving the risks associated with the transportation and storage of silane gas.

Description

Technical Field

[0001] This application relates to the field of semiconductor material preparation technology, and in particular, to a method and apparatus for preparing nano-silicon powder. Background Technology

[0002] Silicon, as a crucial semiconductor material, plays a vital role in the information revolution. Nano-silicon powder, as an emerging material, possesses enormous potential market and application prospects in fields such as lithium-ion battery anode materials, photovoltaic materials, ceramic materials, composite materials, and catalytic materials. For example, adding a certain proportion of nano-silicon powder to the carbon anode of a lithium-ion battery to create a silicon-carbon anode composite material can replace traditional carbon anode materials, exhibiting higher specific capacity and better cycle performance.

[0003] Currently, most chemical methods for preparing nano-silicon powder use silane (SiH4) as the reactant. The main technologies include plasma-enhanced chemical vapor deposition (PECVD) and laser-induced chemical vapor deposition (LICVD). PECVD utilizes plasma generated by radio frequency glow discharge as a heat source to decompose silane under vacuum conditions, thereby producing nano-silicon powder. LICVD utilizes the resonant absorption of a specific wavelength of laser light by silane gas to induce laser pyrolysis of the silane gas, thus producing nano-silicon powder.

[0004] However, the above preparation methods all use silane gas as the reactant gas. The traditional magnesium silicide method or chlorosilane reduction method has a complex reaction path, produces many by-products, and affects the purity of nano-silicon powder. Furthermore, since silane is a flammable and explosive gas, there are significant safety hazards in transportation and storage. At the same time, the above preparation process may be accompanied by strong radiation or harmful gases. Summary of the Invention

[0005] In view of this, this application provides a method and apparatus for preparing nano-silicon powder, which aims to improve the significant safety hazards of silanes during transportation and storage, while reducing production costs and improving the performance of nano-silicon powder.

[0006] On one hand, this application provides a method for preparing nano-silicon powder, the method comprising: Purified silicon is placed in a first chamber and heated to a first preset temperature to activate it. Hydrogen gas is introduced into the first chamber, and the hydrogen gas decomposes into hydrogen atoms at a second preset temperature. The hydrogen atoms react with the activated purified silicon to obtain silane. The silane undergoes a pyrolysis reaction at a third preset temperature to obtain a nano-silicon powder precursor. The nano-silicon powder precursor is placed in the second cavity for post-processing to obtain nano-silicon powder.

[0007] As a further improvement to this application, the step of placing purified silicon in a first chamber and heating it to a first preset temperature to activate it, introducing hydrogen gas into the first chamber, and decomposing the hydrogen gas into hydrogen atoms at a second preset temperature, wherein the hydrogen atoms react with the activated purified silicon to obtain silane, includes: placing purified silicon in the first chamber and using a vacuum assembly to achieve a vacuum degree of 10 in the first chamber. -5 Pa to 10 -4 Pa; The purified silicon is heated by a first heating component to a temperature of 500°C to 1400°C and activated; Hydrogen gas is introduced into the first chamber to maintain the gas pressure in the first chamber at 10 Pa to 10 kPa; The hydrogen gas is heated and decomposed by a second heating component at a temperature of 1600°C to 2500°C, so that the hydrogen gas reaches the second preset temperature and decomposes into hydrogen atoms, and the hydrogen atoms react with the activated purified silicon to obtain silane.

[0008] As a further improvement of this application, the silane undergoes a pyrolysis reaction at a third preset temperature to obtain a nano-silicon powder precursor, comprising: heating the silane through a second heating component, wherein the temperature of the second heating component is 1600°C to 2500°C, so that the temperature of the silane reaches the third preset temperature and undergoes a pyrolysis reaction to obtain the nano-silicon powder precursor.

[0009] As a further improvement of this application, the nano-silicon powder precursor is placed in a second cavity for post-processing to obtain nano-silicon powder, including: heating the nano-silicon powder precursor in an inert atmosphere or vacuum environment to a temperature of 100°C to 600°C and holding it at that temperature for 0.5h to 2h; the nano-silicon powder precursor is naturally cooled as the temperature in the second cavity decreases to obtain the nano-silicon powder.

[0010] On the other hand, this application also provides an apparatus for preparing nano-silicon powder, the apparatus comprising: The device includes a first cavity, which has an activation zone, a pyrolysis zone, and a collection zone. The activation zone is equipped with a first heating component for heating purified silicon to activate it. The pyrolysis zone is equipped with a second heating component for heating hydrogen and / or silane to decompose the hydrogen into hydrogen atoms and cause the silane to undergo a pyrolysis reaction to obtain a nano-silicon powder precursor. The collection zone is equipped with a manifold located directly below the second heating component.

[0011] As a further improvement of this application, the distance between the activation zone and the pyrolysis zone is 0.5 cm to 20 cm.

[0012] As a further improvement of this application, both the first heating component and the second heating component are hot wires.

[0013] As a further improvement of this application, the device further includes a first vacuum assembly, which is located outside the first cavity and communicates with the first cavity to achieve a vacuum level of 10 within the first cavity. -5 Pa to 10 -4 Pa.

[0014] As a further improvement of this application, the device further includes a second cavity and a second vacuum assembly; the second cavity is connected to the bottom end of the manifold to allow the nano-silicon powder precursor to enter the second cavity; a third heating assembly is provided inside the second cavity to heat the nano-silicon powder precursor to a temperature of 100°C to 600°C; the second vacuum assembly is located outside the second cavity and is connected to the second cavity to achieve a vacuum level of 10... -4 Pa to 10 -2 Pa.

[0015] As a further improvement of this application, the device further includes a second cavity and an air inlet assembly; the second cavity is connected to the bottom end of the manifold to allow the nano-silicon powder precursor to enter the second cavity; a third heating assembly is provided in the second cavity to heat the nano-silicon powder precursor to a temperature of 100°C to 600°C; the air inlet assembly is located outside the second cavity and is connected to the second cavity to introduce inert gas into the second cavity, so that the third heating assembly heats the nano-silicon powder precursor in an inert atmosphere.

[0016] According to the preparation method and apparatus for nano-silicon powder provided in this application, purified silicon and hydrogen are used as the initial reactants. Hydrogen is decomposed into hydrogen atoms, which react with activated silicon to generate silane. Compared to the traditional magnesium silicide method or chlorosilane reduction method, the reaction path is more direct, with fewer byproducts, significantly improving the purity of the nano-silicon powder. It also avoids the transportation and storage of silane gas, thus fundamentally solving the risks associated with silane gas transportation and storage. Secondly, the entire preparation process involves purifying silicon and hydrogen to obtain silane, then using pyrolysis chemical vapor deposition to pyrolyze the silane to obtain nano-silicon powder and generate hydrogen. The hydrogen and the hot filament work together as a catalyst, and the process does not produce strong radiation or harmful gases, making it green and safe. Furthermore, the post-processed nano-silicon powder has the following advantages: reduced lattice defects, adjustable crystallinity within a wide range, precise control over particle size, uniformity, and hydrogen content, resulting in high product stability and excellent performance. Attached Figure Description

[0017] It should be understood that the following figures only illustrate certain embodiments of this application and should not be construed as limiting the scope.

[0018] It should be understood that the same or similar reference numerals are used in the accompanying drawings to denote the same or similar elements.

[0019] It should be understood that the accompanying drawings are only schematic, and the dimensions and scales of the elements in the drawings are not necessarily precise.

[0020] Figure 1 This is a flowchart illustrating an exemplary method for preparing nano-silicon powder.

[0021] Figure 2 This is a schematic diagram of an exemplary apparatus for preparing nano-silicon powder.

[0022] Explanation of reference numerals in the attached drawings: 1. First cavity; 11. First air intake assembly; 12. Crucible; 13. First heating assembly; 14. Second heating assembly; 15. First vacuum assembly; 16. Manifold; 2. Second cavity; 21. Third heating assembly; 22. Second vacuum assembly; 23. Second air intake assembly. Detailed Implementation

[0023] Numerous specific details are set forth below to provide an understanding of the structure, function, and use of the embodiments described and illustrated in the specification and figures. It is to be understood that the embodiments described and illustrated herein are non-limiting examples, and thus it will be appreciated that the particular structural and functional details disclosed herein are representative and exemplary. Variations and changes may be made to these embodiments without departing from the scope of the claims.

[0024] <Exemplary Method for Preparing Nano-Silicon Powder> See Figure 1 This application provides a method for preparing nano-silicon powder, the method comprising: Purified silicon is placed in the first chamber, and the vacuum level in the first chamber is increased to 10 using a vacuum assembly. - 5 Pa to 10 -4 Pa, the purified silicon is activated by heating with the first heating component; hydrogen gas is introduced into the first chamber, and the hydrogen gas is heated and decomposed into hydrogen atoms at a second preset temperature. The hydrogen atoms react with the activated purified silicon to obtain silane; the generated silane undergoes a pyrolysis reaction at a third preset temperature to obtain a nano-silicon powder precursor; the nano-silicon powder precursor is post-processed to obtain nano-silicon powder.

[0025] In the preparation method of nano-silicon powder described in this embodiment, purified silicon and hydrogen are used as raw materials. This avoids the long-distance transportation required when using silane directly as a raw material, thus eliminating the risk of combustion or explosion of silane during transportation. Secondly, the entire preparation process involves purifying silicon and hydrogen to obtain silane, and then using a pyrolysis chemical vapor deposition process to pyrolyze the silane to obtain nano-silicon powder and generate hydrogen. The hydrogen and the hot filament work together as a catalyst, and this process does not produce strong radiation or harmful gases, making it green and safe. In addition, the post-processed nano-silicon powder has the following advantages: reduced lattice defects, adjustable crystallinity within a wide range, precise control of particle size, uniformity, and hydrogen content, resulting in high product stability and excellent performance.

[0026] For example, see Figures 1 to 2 The process of preparing silanes by purifying silicon and hydrogen may include: Purified silicon is placed in the first chamber 1, and the first vacuum assembly 15 is used to evacuate the first chamber 1, that is, to remove the gas in the first chamber 1 and make the vacuum degree in the first chamber 1 reach 10. -5 Pa to 10 -4 Pa. It is understandable that when the vacuum level inside the first cavity 1 is 10... -5 Pa to 10 -4 When the pressure is within the range of Pa, the air and / or oxygen content in the first chamber 1 is within a safe range. This prevents the hydrogen gas introduced into the first chamber 1 and the produced silane from spontaneously combusting or exploding, ensuring safety during the preparation of nano-silicon powder.

[0027] Once the gas pressure inside the first chamber 1 reaches the aforementioned range, the purified silicon is heated by the first heating component to a first preset temperature, which can be, for example, 500°C to 1400°C. When the purified silicon reaches the aforementioned temperature, it can be activated, making it easier for the purified silicon to react with hydrogen atoms to obtain silane.

[0028] Optionally, the first preset temperature can be, for example, 500℃, 600℃, 700℃, 800℃, 900℃, 1000℃, 1100℃, 1150℃, 1200℃, 1250℃, 1300℃, 1350℃, or 1400℃. In use, the first preset temperature can be adaptively adjusted according to the particle size of the purified silicon and the gas pressure in the first chamber 1, and is not limited to the temperatures listed above. For example, when the particle size of the purified silicon is small, the first preset temperature can be appropriately lowered; when the particle size of the purified silicon is large, the first preset temperature can be appropriately increased. Similarly, when the gas pressure in the first chamber 1 is low, the first preset temperature can be appropriately lowered; when the gas pressure in the first chamber 1 is high, the first preset temperature can be appropriately increased.

[0029] Once the purified silicon reaches the required temperature, hydrogen gas is introduced into the first chamber 1. For example, a certain amount of hydrogen gas can be introduced into the first chamber 1 to maintain the gas pressure in the first chamber 1 at 10 Pa to 10 kPa. This ensures that there is sufficient hydrogen gas in the first chamber 1 to react fully with the activated purified silicon to obtain silane, and also avoids waste caused by excessive hydrogen gas that cannot be fully decomposed.

[0030] Optionally, hydrogen gas is introduced into the first chamber 1, and the gas pressure inside the first chamber 1 can be 10 Pa, 20 Pa, 50 Pa, 100 Pa, 200 Pa, 300 Pa, 500 Pa, 1 kPa, 2 kPa, 5 kPa, or 10 kPa, etc. In use, the gas pressure inside the first chamber 1 can be adaptively adjusted according to factors such as the volume of the first chamber 1 and / or the flow rate of hydrogen gas, and is not limited to the pressure values ​​listed above.

[0031] After hydrogen gas is introduced into the first cavity 1, the hydrogen gas is heated and decomposed by the second heating component 14. The temperature of the second heating component 14 can be, for example, 1600°C to 2500°C, so that the hydrogen gas reaches the second preset temperature and decomposes into hydrogen atoms.

[0032] Optionally, the temperature of the second heating element 14 can be, for example, 1600℃, 1700℃, 1800℃, 1900℃, 2000℃, 2100℃, 2200℃, 2300℃, 2400℃, or 2500℃. In use, the temperature of the second heating element 14 can be adaptively adjusted according to factors such as the air pressure inside the first cavity 1, and is not limited to the temperatures listed above. For example, when the air pressure inside the first cavity 1 is low, the temperature of the second heating element 14 can be appropriately lowered; when the air pressure inside the first cavity 1 is high, the temperature of the second heating element 14 can be appropriately increased.

[0033] After purifying silicon by reacting it with hydrogen atoms to obtain silane, the resulting silane undergoes a pyrolysis reaction at a third preset temperature to obtain a precursor for nano-silicon powder. This process may include, for example, the following: The generated silane is transported to the region of the second heating element 14 due to the pressure difference. The second heating element 14 then heats the silane. The temperature of the second heating element 14 can be, for example, between 1600°C and 2500°C. When the silane is heated to a third preset temperature, it undergoes a pyrolysis reaction. The pyrolysis of the silane yields a nano-silicon powder precursor and hydrogen gas. The nano-silicon powder precursor can be, for example, silicon powder with poor lattice, particle size, and stability properties. When the second heating element 14 meets the above temperature range, it ensures that the heating temperature of the silane is high enough to allow the produced silane to be pyrolyzed promptly and completely.

[0034] Optionally, the temperature of the second heating element 14 can be, for example, 1600℃, 1700℃, 1800℃, 1900℃, 2000℃, 2100℃, 2200℃, 2300℃, 2400℃, or 2500℃. In use, the temperature of the second heating element 14 can be adaptively adjusted according to factors such as the air pressure inside the first cavity 1, and is not limited to the temperatures listed above. For example, when the air pressure inside the first cavity 1 is low, the temperature of the second heating element 14 can be appropriately lowered; when the air pressure inside the first cavity 1 is high, the temperature of the second heating element 14 can be appropriately increased.

[0035] The precursor for nano-silicon powder obtained from the pyrolysis of silane undergoes specific post-processing to produce nano-silicon powder. This post-processing may include, for example: The precursor of nano-silicon powder is heated in an inert atmosphere or vacuum environment to a temperature of 100℃ to 600℃ and held at that temperature for 0.5h to 2h. The precursor of nano-silicon powder is then naturally cooled with the temperature inside the second chamber 2 to obtain nano-silicon powder.

[0036] Specifically, a specific structure can be used to transport the nano-silicon powder precursor located in the first chamber 1 to the second chamber 2 for post-processing in the second chamber 2. The post-processing in the second chamber 2 can be carried out in a vacuum environment or in an inert atmosphere environment.

[0037] Taking post-processing in a vacuum environment as an example: for instance, the vacuum level inside chamber 2 can be maintained at 10. -4 Pa to 10 -2 Within the Pa range, the nano-silicon powder precursor located in the second cavity 2 is then heated to a temperature of 100℃ to 600℃ and held at that temperature for 0.5h to 2h. Heating is then stopped, allowing the nano-silicon powder precursor to cool naturally with the temperature within the second cavity 2. It is understood that this cooling process is relatively slow, with a corresponding cooling rate of less than 100℃ / s. This not only optimizes the lattice defects in the nano-silicon powder precursor and stabilizes the crystal form, but also inhibits abnormal grain growth, improves the consistency and stability of the nano-silicon powder structure, and is beneficial for enhancing the various properties of the nano-silicon powder.

[0038] During use, parameters such as the heating temperature of the nano-silicon powder precursor, the holding time, and the vacuum level in the second chamber 2 can be adjusted adaptively according to actual working conditions. For example, when the heating temperature of the nano-silicon powder precursor is low, the holding time and / or the vacuum level in the second chamber 2 can be appropriately extended; when the heating temperature of the nano-silicon powder precursor is high, the holding time and / or the vacuum level in the second chamber 2 can be appropriately reduced. This is as long as it ensures that the nano-silicon powder precursor does not undergo abnormal grain growth and / or secondary oxidation.

[0039] Furthermore, when it is necessary to obtain nano-silicon powder with a particle size in the range of 1 nm to 20 nm, the cooling rate of the nano-silicon powder precursor can be set, for example, to 50 °C / s to 100 °C / s; when it is necessary to obtain nano-silicon powder with a particle size in the range of 20 nm to 100 nm, the annealing heating rate can be set, for example, to 1 °C / s to 10 °C / s of the cooling rate of the nano-silicon powder precursor. In use, the cooling rate of the nano-silicon powder precursor can be set according to specific requirements.

[0040] Alternatively, when the post-processing of the nano-silicon powder precursor is carried out in an inert atmosphere, it is necessary to introduce an inert gas such as argon into the second chamber 2 to purge the air and / or oxygen inside the second chamber 2. The remaining post-processing processes can refer to the post-processing processes in the vacuum environment described above, and will not be repeated here.

[0041] <Exemplary Apparatus for Preparing Nano-Silicon Powder> See Figure 2 This application also provides an apparatus for preparing nano-silicon powder. The apparatus includes a first chamber 1, which has an activation zone, a pyrolysis zone, and a collection zone. The activation zone is equipped with a first heating component 13, which heats purified silicon to activate it and react with hydrogen atoms to obtain silane. The pyrolysis zone is equipped with a second heating component 14, which serves two purposes: first, to pyrolyze hydrogen gas to generate hydrogen atoms; and second, to heat the silane to cause it to undergo a pyrolysis reaction to obtain a nano-silicon powder precursor. The collection zone is equipped with a manifold 16, located directly below the second heating component 14. The arrangement order of the activation zone, pyrolysis zone, and collection zone can be understood, for example, as the gas flow direction within the first chamber 1.

[0042] like Figure 2 As shown, the activation region can be understood, for example, as the left-side region within the first cavity 1. The first heating component 13 located within the activation region may include, for example, a resistance wire and a crucible 12. The resistance wire may be uniformly arranged along the height direction of the crucible 12 on the outer surface of the crucible 12 to heat the purified silicon placed inside the crucible 12 and activate the purified silicon.

[0043] As an alternative implementation, a hot wire can be used instead of a resistance wire. That is, the first heating assembly 13 includes a hot wire (not shown) and a crucible 12. The hot wire can then be suspended inside the crucible 12 to heat the purified silicon within it. The hot wire can be, for example, a tungsten wire, tantalum wire, or molybdenum wire, to ensure that it does not melt at high temperatures ranging from 500°C to 1400°C. The number of hot wires can be adjusted adaptively based on factors such as the size of the crucible 12 and the diameter of the hot wire; this application does not impose a specific limitation on the number of hot wires.

[0044] The pyrolysis zone can be understood, for example, as the right-hand region of the activation zone within the first cavity 1. The second heating component 14 located in the pyrolysis zone can be, for example, multiple heating wires. The multiple heating wires can be arranged along the length of the first cavity 1 within the pyrolysis zone so that the hydrogen and silane supplied to the pyrolysis zone can be pyrolyzed in a timely and sufficient manner.

[0045] The heating wire can be one or more of tungsten wire, tantalum wire, and molybdenum wire, and its diameter can be set to, for example, 0.5 mm to 5.0 mm. This prevents the heating wire from overheating and melting. The number of heating wires and the spacing between adjacent heating wires can be adjusted according to the size of the first cavity 1. This application does not impose specific limitations on the number of heating wires or the spacing between adjacent heating wires.

[0046] Preferably, a first gas inlet assembly 11 is provided in the left-hand region of the activation zone within the first cavity 1. The first gas inlet assembly 11 may include, for example, a gas pipeline and a gas cylinder for storing hydrogen, wherein the gas cylinder is located outside the first cavity 1, and the gas pipeline connects the gas cylinder and the first cavity 1. For example, the inlet end of the gas pipeline is connected to the gas cylinder, and the outlet end of the gas pipeline is located inside the first cavity 1, thus allowing hydrogen to be delivered into the first cavity 1 via the gas pipeline.

[0047] Preferably, multiple gas channels can be provided on the side of the crucible 12 near the second heating component 14 to shorten the path of the silane to the pyrolysis zone as much as possible, so that the obtained silane can reach the pyrolysis zone in a timely and rapid manner for pyrolysis reaction. The multiple gas channels can be, for example, pores arranged on the side wall of the crucible 12, or multiple gas pipelines connecting the crucible 12 and the pyrolysis zone. In use, the arrangement of the gas channels can be adaptively adjusted according to requirements, and is not limited to the methods listed above.

[0048] The collection area can be understood, for example, as the region below the second heating component 14 within the first cavity 1. The manifold 16 located in the collection area can be positioned directly below multiple hot wires of the second heating component 14, meaning that the orthogonal projections of the multiple hot wires along their length are all within the manifold 16. This ensures that the nano-silicon powder precursor obtained after silane pyrolysis can be collected by the manifold 16. The manifold 16 can be configured as an approximate "cone," meaning that the diameter of the manifold 16 gradually decreases from the end closer to the second heating component 14 to the end farther away from the second heating component 14. Thus, when the nano-silicon powder precursor is collected within the manifold 16, it can flow towards the end farther from the second heating component 14 under the influence of the shape of the manifold 16 itself, facilitating subsequent collection of the nano-silicon powder precursor.

[0049] It should be noted that the activation zone, pyrolysis zone and collection zone in the first cavity 1 are artificially divided areas, and there is no strict boundary between two adjacent areas.

[0050] In one optional embodiment, the distance between the activation zone and the pyrolysis zone is 0.5 cm to 20 cm. This distance can be understood as the minimum distance between the activation zone and the pyrolysis zone, that is, the distance between the rightmost edge of the activation zone and the leftmost edge of the pyrolysis zone along the length of the first cavity 1. Since there is no strict boundary between the activation zone and the pyrolysis zone, in use, the outer surface of the crucible 12 closest to the pyrolysis zone can be used as the rightmost edge of the activation zone, and the hottest wire closest to the crucible 12 as the leftmost edge of the pyrolysis zone, and these can be used as a reference to adjust the distance between the activation zone and the pyrolysis zone.

[0051] The distance between the activation zone and the pyrolysis zone within the aforementioned range can avoid excessive distance between them, allowing hydrogen atoms to react with the purified silicon in the activation zone in a timely and rapid manner to generate silanes. This enables the silanes to reach the pyrolysis zone in a timely and rapid manner for pyrolysis, thereby improving the preparation efficiency of nano-silicon powder.

[0052] Optionally, the distance between the activation zone and the pyrolysis zone can be 0.5cm, 0.7cm, 1cm, 3cm, 5cm, 8cm, 9cm, 10cm, 12cm, 14cm, 15cm, 17cm, 18cm, 19cm, or 20cm, etc. In use, the distance between the activation zone and the pyrolysis zone can be adaptively adjusted according to factors such as the size of the first cavity 1 and the temperature of the hot wire, and is not limited to the distances listed above.

[0053] The first chamber 1 is equipped with a vacuum assembly, which may be, for example, a first vacuum assembly 15. The first vacuum assembly 15 maintains the vacuum level within the first chamber 1, ensuring that the purification of silicon activation, hydrogen decomposition, and silane pyrolysis are all carried out in the required vacuum environment, thereby guaranteeing the safety and stability of the entire preparation process. The first vacuum assembly 15 may also include, for example, a vacuum pump and a gas pipeline, wherein the vacuum pump is located outside the first chamber 1, and the gas pipeline connects the vacuum pump to the first chamber 1. For example, under the action of the vacuum pump, the vacuum level of the first chamber 1 can be 10. -5 Pa to 10 -4 Within the range of Pa, oxidation of the silicon surface can be avoided during the purification and activation process; it can also prevent dangerous accidents such as spontaneous combustion or explosion of hydrogen and silane in the first chamber 1.

[0054] like Figure 2As shown, the apparatus for preparing nano-silicon powder may further include a second chamber 2 and a second vacuum assembly 22. The second chamber 2 is connected to the bottom end of the manifold 16, allowing the nano-silicon powder precursor collected by the manifold 16 to be transported into the second chamber 2. A third heating assembly 21 is provided inside the second chamber 2 to heat the nano-silicon powder precursor, maintaining its temperature between 100°C and 600°C. The second vacuum assembly 22 is located outside and connected to the second chamber 2, ensuring a vacuum level of 10⁻⁶ in the second chamber. -4 Pa to 10 -2 Pa.

[0055] It is understood that the nano-silicon powder precursor is post-processed in the second chamber 2. The third heating component 21 is used to heat the nano-silicon powder precursor to a temperature of 100°C to 600°C and hold it at that temperature for 0.5 to 2 hours; heating is then stopped, allowing the nano-silicon powder precursor to cool naturally with the temperature within the second chamber 2. The second vacuum component 22 includes, for example, a vacuum pump and gas piping, wherein the vacuum pump is located outside the second chamber 2 and is connected to the second chamber via the gas piping. The second vacuum component 22 maintains the vacuum level within the second chamber 2 at 10... -4 Pa to 10 -2 Within a certain range (Pa), the entire post-processing of the nano-silicon powder precursor is carried out in a vacuum environment to avoid oxidation or agglomeration of the nano-silicon powder. This post-processing not only optimizes the lattice defects in the nano-silicon powder precursor and stabilizes the crystal form, but also inhibits abnormal grain growth, improves the consistency and stability of the nano-silicon powder structure, and is beneficial to improving the various properties of the nano-silicon powder.

[0056] Optionally, the third heating component 21 can be one or more of the following heating methods: resistance wire, infrared lamp, and induction heating. During use, the heating method of the third heating component 21 can be selected according to the actual working conditions, so that the temperature of the nano-silicon powder precursor is maintained between 100℃ and 600℃.

[0057] Alternatively, the apparatus for preparing nano-silicon powder may further include a second chamber 2 and a second air inlet assembly 23. Unlike the embodiments described above, the post-processing of the nano-silicon powder precursor within the second chamber 2 is performed in an inert atmosphere. Specifically, the second air inlet assembly 23 is used to introduce argon or other inert gases into the second chamber 2 to purge air and / or oxygen from the chamber, ensuring that the entire post-processing of the nano-silicon powder precursor is carried out in an inert atmosphere, thus preventing oxidation of the nano-silicon powder.

[0058] Furthermore, the second gas inlet assembly 23 may include, for example, a gas pipeline and a gas cylinder for storing inert gases such as argon or nitrogen, wherein the gas cylinder is located outside the second cavity 2, and the gas pipeline connects the gas cylinder and the second cavity 2. For example, the inlet end of the gas pipeline is connected to the gas cylinder, and the outlet end of the gas pipeline is located inside the second cavity 2, thus allowing the inert gas to be delivered into the second cavity 2 via the gas pipeline. The remaining post-processing procedures can refer to the post-processing procedures in the vacuum environment described above, and will not be repeated here.

[0059] It should be noted that the elements described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this application will not describe the various possible combinations separately.

[0060] It should be understood that multiple components and / or parts can be provided by a single integrated component or part. Alternatively, a single integrated component or part can be divided into multiple separate components and / or parts. The use of the public designation "a" or "an" to describe a component or part is not intended to exclude other components or parts.

[0061] It should be understood that although terms such as "first" or "second" may be used in this application to describe various elements (such as the first heating assembly and the second heating assembly), these elements are not defined by these terms, which are only used to distinguish one element from another.

[0062] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0063] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preparing nano-silicon powder, characterized in that, include: The purified silicon is placed in the first chamber and heated to a first preset temperature to activate it. Hydrogen gas is introduced into the first cavity, and the hydrogen gas is heated and decomposed into hydrogen atoms at a second preset temperature. The hydrogen atoms react with activated purified silicon to obtain silane. The silane undergoes a pyrolysis reaction at a third preset temperature to obtain a nano-silicon powder precursor; The nano-silicon powder precursor is placed in the second cavity for post-processing to obtain nano-silicon powder.

2. The preparation method according to claim 1, characterized in that, The process involves placing purified silicon in a first chamber and heating it to a first preset temperature to activate it. Hydrogen gas is then introduced into the first chamber, and the hydrogen gas decomposes into hydrogen atoms at a second preset temperature. The hydrogen atoms react with the activated purified silicon to yield silane, comprising: Purified silicon is placed in the first chamber, and the vacuum level in the first chamber is increased to 10 using a vacuum assembly. -5 Pa to 10 -4 Pa; The purified silicon is heated by the first heating component to a temperature of 500°C to 1400°C and activated. Hydrogen gas is introduced into the first cavity to maintain the gas pressure in the first cavity at 10 Pa to 10 kPa; The hydrogen gas is heated and decomposed by a second heating component, the temperature of which is 1600°C to 2500°C, so that the hydrogen gas reaches the second preset temperature and decomposes into hydrogen atoms. The hydrogen atoms react with the activated purified silicon to obtain the silane.

3. The preparation method according to claim 2, characterized in that, The silane undergoes a pyrolysis reaction at a third preset temperature to obtain a nano-silicon powder precursor, comprising: The silane is heated by the second heating component, the temperature of which is 1600°C to 2500°C, so that the silane reaches the third preset temperature and undergoes a pyrolysis reaction to obtain the nano-silicon powder precursor.

4. The preparation method according to claim 3, characterized in that, The nano-silicon powder precursor is placed in a second chamber for post-processing to obtain nano-silicon powder, including: The nano-silicon powder precursor is heated in an inert atmosphere or vacuum environment to a temperature of 100°C to 600°C and held at that temperature for 0.5h to 2h. The nano-silicon powder precursor is naturally cooled by the temperature inside the second cavity to obtain the nano-silicon powder.

5. An apparatus for preparing nano-silicon powder using the preparation method according to any one of claims 1 to 4, characterized in that, It includes a first cavity, which has an activation zone, a pyrolysis zone and a collection zone; The activation zone is provided with a first heating component, which is used to heat the purified silicon to activate it. The pyrolysis zone is equipped with a second heating component, which is used to heat hydrogen and / or silane to decompose the hydrogen to produce hydrogen atoms, and to cause the silane to undergo a pyrolysis reaction to obtain nano-silicon powder precursor. The collection area is equipped with a manifold, which is located directly below the second heating component.

6. The apparatus as claimed in claim 5, characterized in that, The distance between the activation zone and the pyrolysis zone is 0.5 cm to 20 cm.

7. The apparatus as claimed in claim 5, characterized in that, Both the first heating element and the second heating element are heating wires.

8. The apparatus as claimed in claim 5, characterized in that, It also includes a first vacuum assembly, which is located outside the first cavity and communicates with the first cavity to achieve a vacuum level of 10 within the first cavity. -5 Pa to 10 -4 Pa.

9. The apparatus as claimed in claim 5, characterized in that, It also includes a second cavity and a second vacuum assembly; The second cavity is connected to the bottom end of the busbar so that the nano-silicon powder precursor can enter the second cavity; The second cavity is provided with a third heating component, which is used to heat the nano-silicon powder precursor to a temperature of 100°C to 600°C. The second vacuum assembly is located outside the second cavity and communicates with the second cavity, so that the vacuum level of the second cavity is 10. -4 Pa to 10 -2 Pa.

10. The apparatus as claimed in claim 5, characterized in that, It also includes a second chamber and an air intake assembly; The second cavity is connected to the bottom end of the busbar so that the nano-silicon powder precursor can enter the second cavity; The second cavity is provided with a third heating component, which is used to heat the nano-silicon powder precursor to a temperature of 100°C to 600°C. The air intake assembly is located outside the second cavity and communicates with the second cavity to introduce inert gas into the second cavity, so that the third heating assembly heats the nano-silicon powder precursor in an inert atmosphere.

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