CN118888736B - Method and system for preparing carbon-encapsulated silicon nanoparticles - Google Patents
Method and system for preparing carbon-encapsulated silicon nanoparticles Download PDFInfo
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- 239000005543 nano-size silicon particle Substances 0.000 title claims abstract description 129
- 238000000034 method Methods 0.000 title claims abstract description 50
- 238000006243 chemical reaction Methods 0.000 claims abstract description 105
- 239000011852 carbon nanoparticle Substances 0.000 claims abstract description 82
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 60
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 59
- 238000002360 preparation method Methods 0.000 claims abstract description 18
- 239000007789 gas Substances 0.000 claims description 48
- 239000000843 powder Substances 0.000 claims description 22
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 18
- 238000005336 cracking Methods 0.000 claims description 16
- 239000011261 inert gas Substances 0.000 claims description 6
- 239000011863 silicon-based powder Substances 0.000 claims description 6
- 230000001133 acceleration Effects 0.000 claims description 5
- 230000007613 environmental effect Effects 0.000 claims description 4
- 230000002596 correlated effect Effects 0.000 claims description 3
- 238000000605 extraction Methods 0.000 claims description 3
- 238000012423 maintenance Methods 0.000 claims description 3
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 abstract description 12
- 238000004519 manufacturing process Methods 0.000 abstract description 7
- 230000008569 process Effects 0.000 abstract description 6
- 238000003860 storage Methods 0.000 abstract description 3
- 238000005516 engineering process Methods 0.000 abstract description 2
- 238000002156 mixing Methods 0.000 abstract description 2
- 239000007773 negative electrode material Substances 0.000 abstract description 2
- 239000002994 raw material Substances 0.000 abstract 1
- 239000002245 particle Substances 0.000 description 24
- 229910052710 silicon Inorganic materials 0.000 description 12
- 239000010703 silicon Substances 0.000 description 12
- 239000010405 anode material Substances 0.000 description 7
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 238000001000 micrograph Methods 0.000 description 4
- 238000007599 discharging Methods 0.000 description 3
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- 238000009776 industrial production Methods 0.000 description 3
- 229910052755 nonmetal Inorganic materials 0.000 description 3
- 238000012546 transfer Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000002848 electrochemical method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000000149 penetrating effect Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000002210 silicon-based material Substances 0.000 description 2
- 239000013543 active substance Substances 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 238000003776 cleavage reaction Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000000875 corresponding effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 238000005538 encapsulation Methods 0.000 description 1
- 230000003631 expected effect Effects 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
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- 238000000197 pyrolysis Methods 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 230000007017 scission Effects 0.000 description 1
- 239000011856 silicon-based particle Substances 0.000 description 1
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/362—Composites
- H01M4/366—Composites as layered products
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- B—PERFORMING OPERATIONS; TRANSPORTING
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- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
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- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
- H01M4/386—Silicon or alloys based on silicon
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- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/027—Negative electrodes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
本发明涉及硅碳负极材料制备技术领域，具体涉及一种制备碳包裹硅纳米微粒的方法及系统；其中方法包括，以碳源气作为工作气体通入等离子发生器中，裂解产生碳纳米微粒；将硅纳米微粒和碳纳米微粒通入具有高温环境的反应腔内；使硅纳米微粒和碳纳米微粒在反应腔内混合并从入料口流向出料口，形成碳包裹硅纳米微粒。本发明通过等离子发生器以碳源气作为工作气体实现对碳源气的裂解以产生碳纳米微粒，该方式附加产物少，可降低生产成本；且本发明的方法基于等离子技术处理直接获得碳纳米微粒，并通过反应腔实现结合形成碳包裹硅纳米微粒，该过程不涉及对碳纳米微粒原料的保存，有利于进一步降低生产成本。
The present invention relates to the technical field of silicon-carbon negative electrode material preparation, and specifically to a method and system for preparing carbon-wrapped silicon nanoparticles; wherein the method comprises: introducing carbon source gas as working gas into a plasma generator to crack and produce carbon nanoparticles; introducing silicon nanoparticles and carbon nanoparticles into a reaction chamber with a high temperature environment; mixing silicon nanoparticles and carbon nanoparticles in the reaction chamber and flowing from a feed inlet to a discharge outlet to form carbon-wrapped silicon nanoparticles. The present invention uses a plasma generator to use carbon source gas as working gas to crack the carbon source gas to produce carbon nanoparticles. This method has few additional products and can reduce production costs. Moreover, the method of the present invention directly obtains carbon nanoparticles based on plasma technology treatment, and combines them through a reaction chamber to form carbon-wrapped silicon nanoparticles. This process does not involve the storage of carbon nanoparticle raw materials, which is conducive to further reducing production costs.
Description
Technical Field
The invention relates to the technical field of preparation of silicon-carbon anode materials, in particular to a method and a system for preparing carbon-coated silicon nanoparticles.
Background
The silicon negative electrode is used as a choice with theoretical specific capacity far higher than that of the graphite negative electrode, related application research is being developed, and new energy automobile enterprises are using silicon materials as battery packs of the negative electrode.
The current silicon negative electrode is mostly a silicon carbon negative electrode, and the volume expansion of the silicon material can reach 300% in the charge and discharge process, so that the problems of material breakage, active substance falling, battery pack deformation and the like can be caused in one charge and discharge cycle, and the cycle stability and the service life of the battery are seriously affected. Therefore, the main stream is to adopt a silicon-carbon negative electrode, namely, nano silicon particles are wrapped in carbon particles.
Based on this, how to prepare the silicon-carbon anode material becomes a research hot spot direction. The main method for preparing the silicon-carbon negative electrode at present comprises the steps of adopting a porous carbon coating mode, namely, injecting silicon nanoparticles into the porous carbon particles through jet flow, wherein in the process of injecting the silicon nanoparticles into the porous carbon, part of the silicon nanoparticles are adhered to the surface of the porous carbon, namely, all the silicon nanoparticles cannot be coated in the porous carbon particles, and the silicon-carbon negative electrode material prepared by the scheme still has the problem of unstable charge-discharge cycle.
In order to obtain a better silicon-carbon anode material and avoid the problems of the method, the invention aims to provide a novel method and a system for preparing carbon-coated silicon nano particles.
Disclosure of Invention
The invention aims to provide a method and a system for preparing carbon-coated silicon nano particles, which are used for producing and preparing a silicon-carbon anode material with better quality by adopting a method different from the preparation method flow of the silicon-carbon anode material in the prior art.
The invention is realized by the following technical scheme:
in a first aspect, there is provided a method of preparing carbon-coated silicon nanoparticles comprising:
introducing carbon source gas serving as working gas into a plasma generator, and cracking to generate carbon nano particles;
introducing silicon nanoparticles and carbon nanoparticles into a reaction cavity with a high-temperature environment;
the silicon nano particles and the carbon nano particles are mixed in the reaction cavity and flow from the feed inlet to the discharge outlet, so that the carbon-coated silicon nano particles are formed.
Further, the silicon nanoparticles were obtained as follows:
gasifying the silicon powder by a plasma generator to generate the silicon nano particles;
The plasma flame temperature emitted by the plasma generator is higher than 2300 ℃.
Further, the method for maintaining the temperature in the reaction chamber is as follows:
and injecting plasma flame between the feed inlet and the discharge outlet of the reaction cavity to ensure that the reaction cavity maintains the required environment temperature for combining the silicon nano particles and the carbon nano particles.
Further, the introducing the silicon nanoparticles and the carbon nanoparticles into the reaction chamber with the high-temperature environment is specifically as follows:
The silicon nanoparticles and the carbon nanoparticles enter the reaction cavity through different feed inlets.
Furthermore, the silicon nano particles are provided with positive charges or negative charges by an electrochemical method before being introduced into the reaction cavity, and the carbon nano particles are provided with charges which are opposite to the electrical charges of the silicon nano particles by an electrochemical method before being introduced into the reaction cavity.
In a second aspect, based on the principle method, a method for preparing carbon-coated silicon nanoparticles is provided, which is easier to be practically applied, and includes:
the method comprises the steps of introducing silicon nanoparticles generated after silicon powder is gasified by a first plasma generator into a reaction cavity through a first feed inlet, arranging an interface of a third plasma generator between the feed inlet and a discharge outlet of the reaction cavity, and injecting plasma flame into the reaction cavity through the third plasma generator to maintain a target environmental temperature in the reaction cavity;
Introducing carbon source gas serving as working gas into a second plasma generator, cracking to generate carbon nano particles, and introducing the carbon nano particles into the reaction cavity through a second feed inlet;
negative pressure is generated at the discharge port of the reaction cavity through the air extraction equipment, so that silicon nanoparticles and carbon nanoparticles flow to the discharge port from the feed port of the reaction cavity to form carbon-coated silicon nanoparticles.
Further, before the silicon nanoparticles are introduced into the reaction cavity through the first feed inlet, the method further comprises:
The silicon nanoparticles are passed through the first high-voltage electrostatic chamber at a high speed such that the silicon nanoparticles have a positive or negative charge.
Further, before the carbon nanoparticles are introduced into the reaction cavity through the second feed inlet, the method further comprises:
The carbon nanoparticles are passed through the second high-voltage electrostatic chamber at a high speed such that the carbon nanoparticles have an opposite electrical charge to the silicon nanoparticles.
Further, the number of the third plasma generators is positively correlated with the distance from the feed inlet to the discharge outlet.
Further, the temperature of the plasma flame generated by the first plasma generator is 2600-3000 ℃, the temperature of the plasma flame generated by the second plasma generator is 800-1500 ℃, the temperature of the plasma flame generated by the third plasma generator is 800-850 ℃, and the working gas adopts inert gas.
In a third aspect, based on the implementation of the specific method, a system for preparing carbon-coated silicon nanoparticles is provided, including:
The reaction cavity comprises a first feeding port, a second feeding port, a discharge port and a flange interface, wherein the first feeding port and the second feeding port are both positioned at a first end of the reaction cavity, the discharge port is positioned at a second end far away from the first end, and the flange interface is arranged between the first end and the second end;
The device comprises silicon nano particle generating equipment, a first plasma generator, a powder feeder and a powder preparation cavity, wherein a powder outlet of the powder feeder and a flame outlet of the first plasma generator are arranged in the powder preparation cavity, the powder preparation cavity comprises a silicon nano particle outlet, and the silicon nano particle outlet is communicated to a first feeding port;
The device comprises a first plasma generator, a cracking cavity, a second plasma generator, a first plasma generator and a second plasma generator, wherein a flame outlet of the first plasma generator is arranged in the cracking cavity, the cracking cavity comprises a carbon nano particle outlet, and the carbon nano particle outlet is communicated with a first feeding port;
And the third plasma generator is arranged on the reaction cavity through the flange interface.
The silicon nanometer particle feeding device comprises a silicon nanometer particle outlet, a first feeding port, a first high-voltage electrostatic chamber, a first gas accelerating section, a second gas accelerating section and a second gas accelerating section, wherein the first high-voltage electrostatic chamber is arranged between the silicon nanometer particle outlet and the first feeding port;
a second high-voltage electrostatic chamber is arranged between the carbon nano particle outlet and the second feeding port, and a second gas acceleration section is further arranged between the carbon nano particle outlet and the second high-voltage electrostatic chamber and is used for enabling the gas flow with the carbon nano particles to pass through the second high-voltage electrostatic chamber at a second preset speed.
The technical scheme of the invention has at least the following advantages and beneficial effects:
The invention provides a novel method for producing carbon-coated silicon nanoparticles, which is easy to realize industrially, and aims to realize the cracking of carbon source gas by taking the carbon source gas as working gas through a plasma generator so as to generate carbon nanoparticles, and combine the carbon nanoparticles and silicon nanoparticles in a reaction cavity in a high-temperature environment to form the carbon-coated silicon nanoparticles.
Drawings
FIG. 1 is a schematic flow chart of a method according to embodiment 1 of the present invention;
FIG. 2 is a schematic flow chart of a method according to embodiment 2 of the present invention;
fig. 3 is a schematic diagram of a system structure according to embodiment 3 of the present invention;
FIG. 4 is an electron microscope image of carbon-coated silicon nanoparticles prepared by the technical scheme of the invention;
Fig. 5 is an edge electron microscope image of carbon-coated silicon nanoparticles prepared by the technical scheme of the invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Currently, a silicon-carbon anode material is one of the main ways of improving the battery performance, and related technical schemes for preparing the silicon-carbon anode material exist at present. The current mainstream is easy to realize by adopting a porous carbon coating mode, namely, injecting silicon nano particles into the porous carbon particles by a jet flow method and the like. However, in the process of driving the silicon nanoparticles into the porous carbon, part of the silicon nanoparticles are attached to the surface of the porous carbon, i.e. all the silicon nanoparticles cannot be wrapped in the porous carbon particles, and the silicon nanoparticles attached to the surface of the porous carbon still have a certain influence on the battery. Based on this, the present invention proposes a novel method for preparing carbon-coated silicon nanoparticles.
Example 1
The present embodiment provides a method for preparing carbon-coated silicon nanoparticles, as shown in fig. 1, according to the principle of the method, the prepared silicon nanoparticles and carbon nanoparticles are mixed in a reaction place with a high temperature environment (800-850 ℃) for a certain time, so that the silicon nanoparticles are coated with the carbon nanoparticles to form the carbon-coated silicon nanoparticles. The particle size of the silicon nanoparticles was larger than that of the carbon nanoparticles, as can be seen from fig. 4.
In the invention, in consideration of the need of easy industrial production, the carbon source gas is taken as working gas to be introduced into a plasma generator (namely a second plasma generator), the reaction temperature is about 800-1500 ℃, and the carbon nano particles are generated by pyrolysis, wherein the carbon source gas comprises methane, carbon dioxide and the like. Methane is preferred in the present invention with less additional product during the cracking process.
And mixing the silicon nanoparticles and the carbon nanoparticles in the reaction cavity and flowing from a feed inlet to a discharge outlet to form the carbon-coated silicon nanoparticles. In the scheme, the prepared silicon nanoparticles can be directly fed into a reaction cavity to be combined with carbon nanoparticles generated by cleavage of a plasma generator to form carbon-coated silicon nanoparticles. It should be noted that the silicon nanoparticles and the carbon nanoparticles enter the reaction chamber through different inlets, that is, the silicon nanoparticles and the carbon nanoparticles are performed through separate channels in the early stage.
Because the storage requirements of the silicon nanoparticles are strict, in industrial production, if the existing silicon nanoparticles are directly adopted, good storage environments are required, for example, the nanoscale silicon particles are required to be stored in inert gas to prevent agglomeration and oxidation, which increases the industrial implementation cost. Some of the preservation of the silicon micron-sized particles is easier to achieve and relatively lower in cost than the prior art.
Therefore, in order to reduce the cost of industrial production, the invention provides a preferred embodiment, namely, silicon nanometer particles are directly prepared on a production site by using silicon micron-sized particles, and the specific method is as follows:
The silicon powder (micron-sized) is vaporized by a plasma generator to generate silicon nano particles, wherein the silicon nano particles are mainly prepared by a plasma technology, and in the practical implementation process, the preparation equipment can refer to a non-metal ultrafine powder preparation system and method based on a plasma transfer arc and a powder preparation system and related working method recorded in Chinese patent No. CN 117339520A. The plasma flame temperature emitted by the plasma generator (i.e., the first plasma generator) in this part of the equipment system needs to be 2600-3000 ℃.
For the reaction cavity, the place where the silicon nano particles and the carbon nano particles are combined needs to keep higher environmental temperature, and for the conventional maintenance of the temperature in the reaction cavity, a cladding type heating mode can be adopted, such as the whole reaction cavity is wrapped in a heating cavity heated by an electric heating wire, the mode is easy to realize, but the control of the temperature in the reaction cavity is slower, because the heat follows a heat transfer path from air to a reaction cavity structure to air in the reaction cavity, the mode is insensitive to the control of the temperature, and the device is once stopped and restarted for a longer time.
In the embodiment of the invention, the flange interface penetrating the wall of the reaction cavity is arranged in the reaction cavity, then the flange interface is connected with the plasma generator (namely, the third plasma generator), and the plasma generator is used for directly heating the reaction cavity to reach the required temperature, and the temperature is 800-850 ℃.
In order to fully combine the silicon nano particles and the carbon nano particles in the reaction cavity, the reaction cavity can be increased in the length direction, and a plurality of flange interfaces for fixing the plasma generator can be arranged on the reaction cavity at equal intervals in order to maintain the required temperature in the longer reaction cavity. Regarding the matching relation between the length of the reaction cavity and the number of the plasma generators, according to the data of the current experimental practice, a set of plasma generators are configured in each 0.5-1m interval of the reaction cavity, so that the temperature stability maintenance effect of the reaction cavity is good.
The reaction time of the silicon nanoparticles and the carbon nanoparticles in the reaction cavity is influenced by two factors, namely the length of the reaction cavity and the air suction speed of negative pressure generating equipment at one end of a discharge hole of the reaction cavity. In the industrial manufacturing process, the data such as the size of the reaction cavity is cured in advance, so that in the actual preparation process, the main influencing factor is the air suction speed of the negative pressure generating equipment at one end of the discharge port of the reaction cavity, and the control of the reaction combination time of the silicon nanoparticles and the carbon nanoparticles in the reaction cavity is realized by controlling the air suction speed of the pressure generating equipment.
In order to make the silicon nanoparticles and the carbon nanoparticles combine rapidly in the reaction chamber, the present embodiment also proposes a method in which the silicon nanoparticles are electrochemically charged with positive or negative charges before being introduced into the reaction chamber, and the carbon nanoparticles are electrochemically charged with charges opposite to those of the silicon nanoparticles before being introduced into the reaction chamber. Because the silicon nano particles and the carbon nano particles enter the reaction cavity through different channels, a high-voltage electrostatic chamber (namely a first high-voltage electrostatic chamber and a second high-voltage electrostatic chamber) can be additionally arranged at the position, close to the reaction cavity, of the channel, and the silicon nano particles and the carbon nano particles are charged with opposite polarities through the high-voltage electrostatic chamber, so that the silicon nano particles and the carbon nano particles can be quickly combined together when entering the reaction cavity.
The carbon-coated silicon nano particles prepared by the technical scheme have good expected effect. As shown in fig. 4 and 5, which are electron microscope images obtained by examination of the samples manufactured by the manufacturing method of the present application, it can be seen that the complete encapsulation of the silicon nanoparticles by the carbon nanoparticles is achieved. The dark central part of fig. 4 is silicon nano-particles, the light part wrapping the dark central part is carbon nano-particles, and fig. 5 is the edge contact condition of the silicon nano-particles and the carbon nano-particles, so that good contact can be seen. From the electron microscope images, the prepared carbon-coated silicon nano particles meet the requirements of battery manufacturing.
In addition, as can be seen from fig. 4, the silicon nanoparticles are far larger than the carbon nanoparticles, and in order to enable the silicon nanoparticles to rapidly wrap the carbon nanoparticles, when the silicon nanoparticles and the carbon nanoparticles are charged, the electric charge of the silicon nanoparticles needs to be far larger than the electric charge of the carbon nanoparticles, which is opposite in electric polarity.
Example 2
This example is based on the principle of following example 1, and provides a method for preparing carbon-coated silicon nanoparticles that is easier to put into practical use. As shown in fig. 2, the specific steps are as follows:
the silicon nanometer particles generated after the silicon powder is gasified by the first plasma generator are introduced into the reaction cavity through the first feed inlet, an interface of a third plasma generator is arranged between the feed inlet and the discharge outlet of the reaction cavity, and plasma flame is injected into the reaction cavity through the third plasma generator, so that the target environmental temperature is maintained in the reaction cavity;
Introducing carbon source gas serving as working gas into a second plasma generator, cracking to generate carbon nano particles, and introducing the carbon nano particles into the reaction cavity through a second feed inlet;
negative pressure is generated at the discharge port of the reaction cavity through the air extraction equipment, so that silicon nanoparticles and carbon nanoparticles flow to the discharge port from the feed port of the reaction cavity to form carbon-coated silicon nanoparticles.
As mentioned in example 1, in order to accelerate the binding of the two kinds of particles, the silicon nanoparticles are passed through the first high-voltage electrostatic chamber at a high speed before being introduced into the reaction chamber through the first feed port, thereby causing the silicon nanoparticles to have positive or negative charges.
Before the carbon nano particles are introduced into the reaction cavity through the second feed inlet, the carbon nano particles pass through the second high-voltage electrostatic chamber at a high speed, so that the carbon nano particles have charges opposite to those of the silicon nano particles. Because the two are charged with opposite polarity, the two can be combined together quickly after entering the reaction cavity.
In the embodiment of the invention, the flange interface penetrating through the wall of the reaction cavity is arranged in the reaction cavity, the third plasma generator is connected with the flange interface, and the reaction cavity is directly heated by the third plasma generator to reach the required temperature.
In order to fully combine the silicon nano particles and the carbon nano particles in the reaction cavity, the reaction cavity can be increased in the length direction, and a plurality of flange interfaces for fixing the third plasma generator can be arranged on the reaction cavity at equal intervals in order to maintain the required temperature in the longer reaction cavity. It can be seen that the number of third plasma generators is positively correlated with the distance from the inlet to the outlet.
For the above scheme, the temperature requirements of the plasma flame of each type of plasma generator in this embodiment are as follows, the temperature of the plasma flame generated by the first plasma generator is 2600-3000 ℃, the temperature of the plasma flame generated by the second plasma generator is 800-1500 ℃, the temperature of the plasma flame generated by the third plasma generator is 800-850 ℃, and the inert gas is used as the working gas.
Example 3
The present embodiment provides a specific system design scheme based on the principles of embodiments 1, 2. As shown in fig. 3, the arrows in fig. 3 indicate the flow directions of the gas and the particles, and in particular, the third plasma generator uses the inert gas as the working gas, and the high-temperature plasma flame generated by the third plasma generator directly acts inside the reaction chamber, so that the arrows point to the reaction chamber, and the high-temperature gas can be understood to be introduced into the reaction chamber, which specifically comprises:
The reaction cavity comprises a first feeding port, a second feeding port, a discharging port and a flange interface, wherein the first feeding port and the second feeding port are both positioned at the first end of the reaction cavity, the discharging port is positioned at the second end far away from the first end, the flange interface is arranged between the first end and the second end, and the discharging port is also communicated with negative pressure generating equipment.
The device for producing the silicon nanometer particles comprises a first plasma generator, a powder feeder and a powder preparation cavity, wherein a powder outlet of the powder feeder and a flame outlet of the first plasma generator are arranged in the powder preparation cavity, the powder preparation cavity comprises a silicon nanometer particle outlet, and the silicon nanometer particle outlet is communicated to a first feeding port. The equipment can refer to a nonmetal ultrafine powder preparation system and a nonmetal ultrafine powder preparation method based on a plasma transfer arc in Chinese patent No. CN117339520A, and a related working method thereof.
The device comprises a first plasma generator and a cracking cavity, wherein a flame outlet of the first plasma generator is arranged in the cracking cavity, the cracking cavity comprises a carbon nano particle outlet, and the carbon nano particle outlet is communicated to a first feeding port.
And the third plasma generator is arranged on the reaction cavity through a flange interface.
In order to enable the silicon nanoparticles and the carbon nanoparticles to be rapidly combined in the reaction cavity, a first high-voltage electrostatic chamber is arranged between the silicon nanoparticle outlet and the first feeding port, a first gas accelerating section is further arranged between the silicon nanoparticle outlet and the first high-voltage electrostatic chamber, and the first gas accelerating section is used for enabling the gas flow with the silicon nanoparticles to pass through the first high-voltage electrostatic chamber at a first preset speed. A second high-voltage electrostatic chamber is arranged between the carbon nano particle outlet and the second feeding port, and a second gas accelerating section is arranged between the carbon nano particle outlet and the second high-voltage electrostatic chamber and is used for enabling the gas flow with the carbon nano particles to pass through the second high-voltage electrostatic chamber at a second preset speed.
The high-voltage electrostatic chamber is a cavity which only comprises a particle feeding and outputting port, the cavity is internally provided with an electrode, the electrode comprises a positive electrode (grounded or connected with a high-voltage power supply) and a negative electrode (grounded or connected with the high-voltage power supply), namely the positive electrode is grounded in the high-voltage electrostatic chamber, the negative electrode is connected with the high-voltage power supply, the positive electrode is connected with the high-voltage power supply in the other high-voltage electrostatic chamber, the negative electrode is grounded, the electrode spacing is moderate, so that the particles can pass through quickly but enough charges can be obtained, and the shape of the electrode can be a flat plate type or a net type so as to improve the uniformity of an electric field. In order to prevent the electrode from adsorbing the particles, a first gas accelerating section is further arranged between the silicon nanoparticle outlet and the first high-voltage electrostatic chamber, a second gas accelerating section is further arranged between the carbon nanoparticle outlet and the second high-voltage electrostatic chamber, and the particles pass through the high-voltage electrostatic chamber through the acceleration section by accelerating the airflow with the particles, so that the particles are not adsorbed by the electrode under the condition of realizing charge, and can smoothly enter the subsequent reaction cavity.
The gas accelerating section can reduce the diameter of the gas outlet port, so that the gas pressure of the gas outlet port is higher, and the purpose of increasing the gas flow rate is achieved, or the external high-speed gas flow equipment can directly introduce high-speed gas flow into a corresponding pipeline, which needs to be described, the high-speed gas flow introduced into the pipeline by the external equipment is adopted, inert gas is used, and the scheme in fig. 3 is that the high-speed gas flow introduced into the pipeline by the external equipment is adopted.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (12)
1. A method of preparing carbon-coated silicon nanoparticles comprising:
introducing carbon source gas serving as working gas into a plasma generator, and cracking to generate carbon nano particles;
introducing silicon nanoparticles and carbon nanoparticles into a reaction cavity with a high-temperature environment;
the silicon nano particles and the carbon nano particles are mixed in the reaction cavity and flow from the feed inlet to the discharge outlet, so that the carbon-coated silicon nano particles are formed.
2. The method of preparing carbon-coated silicon nanoparticles of claim 1, wherein the silicon nanoparticles are obtained as follows:
gasifying the silicon powder by a plasma generator to generate the silicon nano particles;
The plasma flame temperature emitted by the plasma generator is higher than 2300 ℃.
3. The method of preparing carbon-coated silicon nanoparticles according to claim 1, wherein the temperature maintenance method in said reaction chamber is as follows:
and injecting plasma flame between the feed inlet and the discharge outlet of the reaction cavity to ensure that the reaction cavity maintains the required environment temperature for combining the silicon nano particles and the carbon nano particles.
4. A method for preparing carbon-coated silicon nanoparticles according to any one of claims 1 to 3, wherein said introducing silicon nanoparticles and carbon nanoparticles into a reaction chamber having a high temperature environment is specifically:
The silicon nanoparticles and the carbon nanoparticles enter the reaction cavity through different feed inlets.
5. The method of claim 4, wherein the silicon nanoparticles are electrochemically charged with a positive or negative charge prior to being introduced into the reaction chamber, and wherein the carbon nanoparticles are electrochemically charged with a charge opposite to the electrical charge of the silicon nanoparticles prior to being introduced into the reaction chamber.
6. A method of preparing carbon-coated silicon nanoparticles comprising:
the method comprises the steps of introducing silicon nanoparticles generated after silicon powder is gasified by a first plasma generator into a reaction cavity through a first feed inlet, arranging an interface of a third plasma generator between the feed inlet and a discharge outlet of the reaction cavity, and injecting plasma flame into the reaction cavity through the third plasma generator to maintain a target environmental temperature in the reaction cavity;
Introducing carbon source gas serving as working gas into a second plasma generator, cracking to generate carbon nano particles, and introducing the carbon nano particles into the reaction cavity through a second feed inlet;
negative pressure is generated at the discharge port of the reaction cavity through the air extraction equipment, so that silicon nanoparticles and carbon nanoparticles flow to the discharge port from the feed port of the reaction cavity to form carbon-coated silicon nanoparticles.
7. The method of preparing carbon-coated silicon nanoparticles according to claim 6, further comprising, before said silicon nanoparticles are introduced into the reaction chamber through the first feed port:
The silicon nanoparticles are passed through the first high-voltage electrostatic chamber at a high speed such that the silicon nanoparticles have a positive or negative charge.
8. The method of preparing carbon-coated silicon nanoparticles according to claim 7, further comprising, before said carbon nanoparticles are introduced into the reaction chamber through the second feed port:
The carbon nanoparticles are passed through the second high-voltage electrostatic chamber at a high speed such that the carbon nanoparticles have an opposite electrical charge to the silicon nanoparticles.
9. The method of preparing carbon-coated silicon nanoparticles as recited in claim 6, wherein the number of said third plasma generators is positively correlated with the distance from the inlet to the outlet.
10. The method of preparing carbon-coated silicon nanoparticles as set forth in any one of claims 6 to 9, wherein the temperature of the plasma flame generated by the first plasma generator is 2600 to 3000 ℃, the temperature of the plasma flame generated by the second plasma generator is 800 to 1500 ℃, the temperature of the plasma flame generated by the third plasma generator is 800 to 850 ℃, and the working gas is inert gas.
11. A system for preparing carbon-coated silicon nanoparticles, comprising:
The reaction cavity comprises a first feeding port, a second feeding port, a discharge port and a flange interface, wherein the first feeding port and the second feeding port are both positioned at a first end of the reaction cavity, the discharge port is positioned at a second end far away from the first end, and the flange interface is arranged between the first end and the second end;
The device comprises silicon nano particle generating equipment, a first plasma generator, a powder feeder and a powder preparation cavity, wherein a powder outlet of the powder feeder and a flame outlet of the first plasma generator are arranged in the powder preparation cavity, the powder preparation cavity comprises a silicon nano particle outlet, and the silicon nano particle outlet is communicated to a first feeding port;
The device comprises a first plasma generator, a cracking cavity, a second plasma generator, a first plasma generator and a second plasma generator, wherein a flame outlet of the first plasma generator is arranged in the cracking cavity, the cracking cavity comprises a carbon nano particle outlet, and the carbon nano particle outlet is communicated with a first feeding port;
And the third plasma generator is arranged on the reaction cavity through the flange interface.
12. The system for preparing carbon-coated silicon nanoparticles according to claim 11, wherein a first high-voltage electrostatic chamber is further provided between said silicon nanoparticle outlet and said first inlet, and a first gas acceleration section is further provided between said silicon nanoparticle outlet and said first high-voltage electrostatic chamber, said first gas acceleration section being adapted to cause a gas flow with silicon nanoparticles to pass through said first high-voltage electrostatic chamber at a first preset speed;
a second high-voltage electrostatic chamber is arranged between the carbon nano particle outlet and the second feeding port, and a second gas acceleration section is further arranged between the carbon nano particle outlet and the second high-voltage electrostatic chamber and is used for enabling the gas flow with the carbon nano particles to pass through the second high-voltage electrostatic chamber at a second preset speed.
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