Preparation system and preparation method of battery negative electrode material and prepared negative electrode material

Abstract

The invention provides a preparation system and a preparation method of a battery negative electrode material and the prepared negative electrode material. The system comprises an electrostatic separation device, an eddy current control device and a gas pulse distribution device, the electrostatic separation device and the gas pulse distribution device are respectively communicated with the vortex control device; carrier gas is introduced into the gas pulse distribution device, and carbon source gas is introduced into the vortex control device; the gas pulse distribution device is used for carrying out reduction reaction on the silicon powder loaded with the catalyst precursor to generate a pretreatment product; the carrier gas enables the pretreated product to enter the vortex control device; the vortex control device is used for enabling the pretreated product to react with the carbon nano tube in a carbon source gas atmosphere, so that the carbon nano tube grows in situ, and a negative electrode material and a product gas are generated; the negative electrode material enters the electrostatic separation device through the product gas; and the electrostatic separation device is used for collecting the negative electrode material and discharging the product gas. The reaction raw materials can be uniformly distributed, and the growth orientation of the carbon nanotubes can be better regulated and controlled.

Description

Technical Field

[0001] The present application relates to the technical field of battery negative electrode material preparation, and in particular to a battery negative electrode material preparation system, preparation method and prepared negative electrode material. Background Art

[0002] With the rapid development of new energy vehicles and portable electronic devices, the requirements for the energy density of lithium-ion batteries are constantly increasing. Due to its high theoretical specific capacity, silicon-based negative electrode materials are considered to be the most promising next-generation lithium-ion battery negative electrode materials.

[0003] However, silicon-based negative electrode materials have a serious volume expansion effect during the charging and discharging process. The volume change during the charging and discharging process can reach more than 300%. This huge volume change will cause material pulverization and electrode structure destruction, thereby affecting the battery's charge and discharge rate performance.

[0004] To solve the above problems, the more common method includes constructing a conductive network to obtain a silicon / carbon nanotube composite negative electrode material. Through reasonable design, carbon nanotubes can form a network structure on the surface of silicon balls. However, during the preparation process of existing silicon / carbon nanotube composite negative electrode materials, there are problems such as difficulty in regulating the growth orientation of carbon nanotubes and uneven distribution of reaction raw materials. Summary of the invention

[0005] The present application provides a preparation system and method of a negative electrode material for a battery, and the prepared negative electrode material, which are used to solve the technical problems in the prior art that the growth orientation of carbon nanotubes is difficult to control and the distribution of reaction raw materials is uneven.

[0006] In a first aspect, the present application provides a system for preparing a negative electrode material for a battery, comprising: an electrostatic separation device, an eddy current control device, and a gas pulse distribution device;

[0007] The electrostatic separation device and the gas pulse distribution device are respectively connected to the vortex control device; the carrier gas is introduced into the gas pulse distribution device, and the carbon source gas is introduced into the vortex control device;

[0008] The gas pulse distribution device is used to carry out a reduction reaction on silicon powder loaded with a catalyst precursor to generate a pre-treated product; and the carrier gas causes the pre-treated product to enter the vortex control device;

[0009] The vortex control device is used to react the pre-treated product with the carbon nanotubes in the carbon source gas atmosphere, so that the carbon nanotubes grow in situ to generate negative electrode materials and product gas; and the product gas causes the negative electrode material to enter the electrostatic separation device;

[0010] The electrostatic separation device is used to collect the negative electrode material and discharge the product gas.

[0011] In one possible implementation, the gas pulse distribution device includes a reactor, a plurality of brackets, and a plurality of honeycomb distribution plates;

[0012] The multiple supports are arranged in the reactor to divide the reactor into multiple reaction chambers, and the multiple reaction chambers are interconnected;

[0013] The plurality of honeycomb distribution plates are respectively arranged on the plurality of brackets, and the honeycomb distribution plates are provided with a plurality of through holes; the bottom end of the reactor is also provided with a gas inlet, and the gas inlet is used to introduce the carrier gas.

[0014] In a possible implementation manner, the gas pulse distribution device further includes a temperature sensor and a gas preheater;

[0015] The temperature sensor is arranged on one side of the reactor, and is used to detect the temperature inside the reactor;

[0016] The gas preheater is arranged on one side of the reactor and close to the bottom end of the reactor, and is used to adjust the temperature in the reactor.

[0017] In a possible implementation manner, the eddy current control device includes an eddy current controller, a housing, and an eddy current intensity detector;

[0018] The eddy current controller is arranged in the housing, and the bottom end of the eddy current controller is connected to the gas pulse distribution device; the eddy current intensity detector is arranged on one side of the eddy current controller, and the eddy current intensity detector is used to detect the eddy current intensity in the housing;

[0019] The bottom end of the shell is also provided with a communication port, and the communication port is used to introduce the carbon source gas.

[0020] In a possible implementation manner, the vortex controller includes a gas outlet and a spiral guide groove;

[0021] The gas outlet is arranged at the top of the vortex controller and is connected to the electrostatic separation device;

[0022] The spiral guide groove is arranged on the vortex controller, and the spiral guide groove is used to guide the carrier gas and the pre-treated product to react with the carbon nanotubes and the carbon source gas, thereby increasing the reaction time to allow them to fully react;

[0023] A plurality of gas nozzles and a plurality of vortex control blades are arranged on the side wall of the vortex controller; the plurality of gas nozzles are used to spray the carbon source gas into the vortex control device so that the vortex control device generates a rotating airflow, and the plurality of vortex control blades control the intensity and direction of the vortex by adjusting the angle of the vortex control blades.

[0024] In one possible implementation, the electrostatic separation device includes a gas rectifier and a product collector;

[0025] The gas rectifier is arranged at the bottom end of the electrostatic separation device and is connected to the vortex control device. The gas rectifier is used to convert the vortex airflow flowing in from the vortex control device into a laminar airflow;

[0026] The product collector is arranged at the top of the electrostatic separation device, and the product collector is used to collect the negative electrode material.

[0027] In a possible implementation manner, a ring-shaped electrode plate is provided on at least one side of the electrostatic separation device;

[0028] The plurality of annular electrode plates are used to separate the product gas and the negative electrode material so that the product gas can be discharged.

[0029] In a second aspect, the present application provides a method for preparing a negative electrode material for a battery, using the system described in any one of the embodiments of the first aspect of the present application, comprising the following steps:

[0030] Adding the silicon powder loaded with the catalyst precursor into the gas pulse distribution device, setting the reaction temperature and reaction pressure to generate the pre-treated product; and introducing the carrier gas to allow the pre-treated product to flow into the vortex control device;

[0031] The carbon source gas is introduced into the vortex control device to react the pre-treated product with the carbon nanotubes added into the vortex control device to generate the product gas and the negative electrode material;

[0032] The product gas flowing into the electrostatic separation device is discharged, and the negative electrode material, ie, the silicon / carbon nanotube composite material, is collected.

[0033] In a possible implementation manner, the carrier gas is selected from one or any proportion of argon, nitrogen or helium;

[0034] And / or, the carbon source gas is selected from one or any combination of methane, ethylene, ethane, propylene or butene;

[0035] And / or, the reaction temperature is 400-1200° C., and the reaction pressure is 0.1-5 MPa;

[0036] And / or, the catalyst precursor includes a hydroxide corresponding to a transition metal;

[0037] And / or, the diameter of the carbon nanotubes in the negative electrode material is 20 to 80 nm;

[0038] And / or, the length of the carbon nanotubes in the negative electrode material is 5 to 20 μm;

[0039] And / or, the particle size of the silicon powder in the negative electrode material is 50 to 200 nm.

[0040] In a third aspect, the present application provides a negative electrode material prepared by the method described in any one of the embodiments provided in the second aspect of the present application.

[0041] The preparation system, preparation method and prepared negative electrode material of battery provided by the present application are passed through an electrostatic separation device, an eddy current control device and a gas pulse distribution device; the electrostatic separation device and the gas pulse distribution device are respectively connected to the eddy current control device; a carrier gas is introduced into the gas pulse distribution device, and a carbon source gas is introduced into the eddy current control device; the gas pulse distribution device is used for reducing silicon powder loaded with a catalyst precursor to generate a pretreated product; and the carrier gas causes the pretreated product to enter the eddy current control device; the eddy current control device is used for reacting the pretreated product with carbon nanotubes under the atmosphere of the carbon source gas, so that the carbon nanotubes are grown in situ to generate negative electrode materials and product gases; and the product gas causes the negative electrode materials to enter the electrostatic separation device; the electrostatic separation device is used for collecting the negative electrode materials and discharging the product gases. Specifically, silicon powder loaded with a catalyst precursor is placed in a gas pulse distribution device 300, and a carrier gas is introduced from the bottom of the gas pulse distribution device 300 to cause the silicon powder loaded with a catalyst precursor to undergo a reduction reaction, so that the catalyst is reduced from an oxidized state to a metallic state to obtain catalytic activity, and a silicon powder loaded with a catalyst, i.e., a pre-treated product, is obtained. Driven by the carrier gas, the pre-treated product is introduced into the vortex control device 200, and the pre-treated product, carbon nanotubes, and the carbon source gas in the vortex state react to make the carbon nanotubes grow in situ, generate negative electrode materials and product gases, and flow into the electrostatic separation device 100 with the vortex gas flow, and the electrostatic separation device 100 converts the vortex gas flow into a laminar gas flow, and separates the negative electrode materials and the product gases, collects the negative electrode materials, and discharges the product gases. In the system of the present application, the gas pulse distribution device 300 can fully distribute the reaction raw materials evenly for reaction, and then make each reaction raw material and the carbon source gas in the vortex control device 200 fully contact and react, so as to better regulate the growth orientation of the carbon nanotubes. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0043] Figure 1 A schematic diagram of the structure of a battery negative electrode material preparation system provided in an embodiment of the present application;

[0044] Figure 2 A schematic diagram of the structure of a gas pulse distribution device for a battery negative electrode material preparation system provided in an embodiment of the present application;

[0045] Figure 3 A schematic diagram of the structure of a honeycomb distribution plate in a gas pulse distribution device of a battery negative electrode material preparation system provided in an embodiment of the present application;

[0046] Figure 4 A schematic diagram of the structure of an eddy current control device for a battery negative electrode material preparation system provided in an embodiment of the present application;

[0047] Figure 5 A schematic diagram of the structure of an electrostatic separation device of a battery negative electrode material preparation system provided in an embodiment of the present application;

[0048] Figure 6 A process flow chart of a method for preparing a negative electrode material for a battery provided in an embodiment of the present application;

[0049] Figure 7 To adopt Figure 1 System and / or Figure 5 Scanning electron microscope image of the negative electrode material prepared by the method;

[0050] Figure 8 To adopt Figure 1 System and / or Figure 5 The first charge and discharge curve of the negative electrode material prepared by the method;

[0051] Fig. 9 To adopt Figure 1 System and / or Figure 5 Rate performance diagram of the negative electrode material prepared by the method.

[0052] Description of reference numerals:

[0053] 100————Electrostatic separation device;

[0054] 110————Gas rectifier;

[0055] 120————annular electrode plate;

[0056] 130————Product collector;

[0057] 200————eddy current control device;

[0058] 210————eddy current controller;

[0059] 211————Gas outlet;

[0060] 212————Gas nozzle;

[0061] 213————Vortex control blades;

[0062] 214————Spiral guide groove;

[0063] 220————housing;

[0064] 230————eddy current intensity detector;

[0065] 300————Gas pulse distribution device;

[0066] 310————reaction chamber;

[0067] 320————honeycomb distribution plate;

[0068] 330————Temperature sensor;

[0069] 340————gas preheater;

[0070] 350————gas inlet;

[0071] 360————Stand;

[0072] 370————reactor.

[0073] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0074] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0075] With the rapid development of new energy vehicles and portable electronic devices, the requirements for the energy density of lithium-ion batteries are constantly increasing. Silicon-based negative electrode materials are considered to be the most promising next-generation lithium-ion battery negative electrode materials because of their theoretical specific capacity of up to 4200mAh / g. However, silicon materials have a serious volume expansion effect during the charging and discharging process, and the volume change during the charging and discharging process can reach more than 300%. This huge volume change will cause material pulverization and electrode structure damage. At the same time, the intrinsic conductivity of silicon materials is poor, which seriously affects the charge and discharge rate performance of the battery. In addition, as the charge and discharge cycle proceeds, the solid electrolyte interface film on the electrode surface will continue to break and regenerate, continuously consuming the electrolyte, further reducing the battery's cycle stability.

[0076] To solve these key problems, researchers have proposed a variety of modification strategies. Among them, the more common methods include nano-sizing, carbon material composites, and conductive network construction. Although nano-sizing can alleviate volume expansion to a certain extent, the specific surface area of ​​nanomaterials is significantly increased, which in turn aggravates side reactions such as electrolyte decomposition. Although simple carbon coating or carbon matrix embedding can improve the conductivity of the material, this composite structure is often destroyed during the cycle process. In recent years, the strategy of constructing a three-dimensional conductive network has received widespread attention, especially the method of composite silicon spheres with carbon nanotubes has shown unique advantages.

[0077] Carbon nanotubes are ideal materials for constructing conductive networks due to their excellent mechanical strength, electrical conductivity and chemical stability. Through reasonable design, carbon nanotubes can form a network structure on the surface of silicon spheres, which not only provides an efficient electron transmission channel, but also the gaps in the network structure can effectively buffer the volume change of silicon materials. However, the preparation of silicon sphere carbon nanotube composites still faces many technical difficulties. Traditional catalyst loading methods, such as impregnation, are difficult to achieve uniform distribution of catalysts, while improved methods such as spraying or electrostatic spraying have the disadvantages of complex equipment and high cost. More importantly, the agglomeration of catalysts will lead to uneven growth of carbon nanotubes, affecting the performance of the final product.

[0078] In terms of the control of the carbon nanotube growth process, the existing technology also has obvious shortcomings. The growth orientation of carbon nanotubes is relatively random, and it is difficult to form an ideal conductive network structure. The unevenness of growth density and length, as well as the entanglement between carbon nanotubes, will affect the comprehensive performance of the composite material. In addition, the existing equipment also faces severe challenges in the control of process parameters. Problems such as uneven temperature field distribution, difficulty in accurately controlling the reducing atmosphere, and difficulty in optimizing the reaction time all restrict the improvement of product quality. The currently commonly used fixed bed reactor has low gas-solid contact efficiency, while the simple fluidized bed cannot achieve precise control of process parameters and is difficult to meet the requirements of large-scale production.

[0079] The present application provides a preparation system and method for a negative electrode material for a battery, and the prepared negative electrode material, which are intended to solve the technical problems in the prior art that the growth orientation of carbon nanotubes is difficult to control and the distribution of reaction raw materials is uneven.

[0080] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0081] Figure 1 This is a schematic diagram of the structure of the battery negative electrode material preparation system provided in the embodiment of the present application. Figure 1 As shown, the system includes: an electrostatic separation device 100, a vortex control device 200 and a gas pulse distribution device 300; the electrostatic separation device 100 and the gas pulse distribution device 300 are respectively connected to the vortex control device 200; a carrier gas is introduced into the gas pulse distribution device 300, and a carbon source gas is introduced into the vortex control device 200. The gas pulse distribution device 300 is used to carry out a reduction reaction on silicon powder loaded with a catalyst precursor to generate a pre-treated product; and the carrier gas causes the pre-treated product to enter the vortex control device 200; the vortex control device 200 is used to react the pre-treated product with carbon nanotubes under the atmosphere of the carbon source gas, so that the carbon nanotubes grow in situ to generate negative electrode materials and product gas; and the product gas causes the negative electrode materials to enter the electrostatic separation device 100; the electrostatic separation device 100 is used to collect the negative electrode materials and discharge the product gas.

[0082] The gas pulse distribution device 300 can be configured as a conical reactor, and a gas inlet is provided at the bottom end thereof for introducing a carrier gas. The bottom diameter of the gas pulse distribution device 300 is smaller than the top diameter, so that the gas pulse distribution device 300 can generate a higher gas flow rate at the bottom, thereby fully fluidizing the reactants. At the same time, in order to ensure that the gas pulse distribution device 300 can operate stably in a high temperature environment, the gas pulse distribution device 300 is made of high temperature resistant alloy materials, such as alloy GH3030, alloy GH3044, alloy GH3536, alloy GH2036 and alloy K4169, which have excellent heat resistance and mechanical strength.

[0083] When the carrier gas enters from the bottom of the gas pulse distribution device 300, it carries the reactants in the device into the vortex control device 200 to carry out the next chemical reaction. For the reactants with uneven particle sizes in the gas pulse distribution device 300, the design of the bottom can produce a larger carrier gas flow rate to ensure sufficient fluidization and mixing of the reactants. At the same time, the conical structure of the device makes the gas flow rate at the top relatively small, which helps to extend the residence time of the reactants, so that the reactants at the top can flow into the vortex control device 200 more evenly, ensuring the efficiency and uniformity of the subsequent reactions.

[0084] The vortex control device 200 can be used to process the reaction raw materials introduced from the gas pulse distribution device 300, and to chemically react with other reaction raw materials and carbon source gas placed in the vortex control device 200. In order to ensure the sufficiency and efficiency of the reaction, the vortex control device 200 can be designed with structures such as spiral grooves and vortex controllers, which can generate complex vortex airflow inside the device, thereby enhancing the mixing and contact between the reaction raw materials and the carbon source gas.

[0085] By introducing a spiral groove in the vortex control device 200, the gas flow will be guided into a spiral path, which can increase the contact area and contact time between the gas and the solid reactant, thereby improving the efficiency of the reaction. In addition, the setting of the vortex controller can further adjust and optimize the speed and direction of the gas flow, so that the carbon source gas forms a stable and strong vortex inside the device, which not only helps the uniform distribution of the reactants, but also promotes the full contact between the reactants and the carbon source gas, thereby ensuring the high purity and high quality of the reaction products. The vortex control device 200 can adapt to the needs of different chemical reactions, provide greater operational flexibility and reaction efficiency, not only improve the overall performance of the reaction, but also effectively reduce the generation of by-products, and ensure the purity and consistency of the final product.

[0086] The electrostatic separation device 100 separates various reaction products and product gases generated from the vortex control device 200. The reaction products mainly include the cathode material, and the product gas includes the carrier gas, the unreacted carbon source gas, and other gases generated after the reaction. The electrostatic separation device 100 is mainly used to effectively separate these reaction products from the product gas, ensure that the product gas is discharged from the system, and efficiently collect the reaction products.

[0087] Since the airflow flowing from the vortex control device 200 into the electrostatic separation device 100 carries the reaction products, and the airflow usually presents a chaotic vortex state, it is possible to effectively separate the reaction products and the product gas by directly separating them. Therefore, the vortex control device 200 adjusts the airflow entering the electrostatic separation device 100 so that it gradually changes from a vortex state to a laminar state, which can significantly reduce the degree of turbulence of the airflow, make the airflow more stable and orderly, and create more ideal conditions for the subsequent separation process. By changing the airflow state from vortex to laminar flow, the electrostatic separation device 100 can more effectively use electrostatic force to separate the reaction products and product gases, which not only improves the separation efficiency, but also reduces energy consumption and equipment wear, and extends the service life of the equipment. In addition, the airflow in the laminar state helps to improve the accuracy of separation and ensure that the collected reaction products have a high purity.

[0088] The catalyst precursor includes the hydroxides corresponding to transition metal iron, cobalt, nickel and transition metal oxides, such as cobalt hydroxide, nickel hydroxide, etc. The carrier gas is an inert gas, such as nitrogen, helium, argon, etc. The carbon source gas is an organic gas containing carbon, such as methane, ethane, ethylene, propylene, etc. The product gas includes the carbon source gas and carrier gas that do not participate in the reaction in the vortex control device 200, and other gases generated by the reaction in the vortex control device 200.

[0089] In the specific implementation process, silicon powder loaded with a catalyst precursor is placed in a gas pulse distribution device 300, and a carrier gas is introduced from the bottom of the gas pulse distribution device 300 to cause the silicon powder loaded with a catalyst precursor to undergo a reduction reaction, so that the catalyst is reduced from an oxidized state to a metallic state to obtain catalytic activity, and silicon powder loaded with a catalyst, i.e., a pretreated product, is obtained. Driven by the carrier gas, the pretreated product is introduced into the vortex control device 200, and the pretreated product, carbon nanotubes and the carbon source gas in a vortex state react to make the carbon nanotubes grow in situ to generate negative electrode materials and product gases, and the carbon nanotubes are introduced into the electrostatic separation device 100 along with the vortex airflow. The electrostatic separation device 100 converts the vortex airflow into a laminar airflow, separates the negative electrode materials and the product gases, collects the negative electrode materials, and discharges the product gases.

[0090] The embodiment of the present application provides a preparation system of negative electrode materials for batteries, through an electrostatic separation device, an eddy current control device and a gas pulse distribution device; the electrostatic separation device and the gas pulse distribution device are respectively connected to the eddy current control device; a carrier gas is introduced into the gas pulse distribution device, and a carbon source gas is introduced into the eddy current control device; the gas pulse distribution device is used for a reduction reaction of silicon powder loaded with a catalyst precursor to generate a pretreated product; and the carrier gas causes the pretreated product to enter the eddy current control device; the eddy current control device is used to react the pretreated product with carbon nanotubes under the atmosphere of the carbon source gas, so that the carbon nanotubes grow in situ to generate negative electrode materials and product gases; and the product gas causes the negative electrode materials to enter the electrostatic separation device; the electrostatic separation device is used to collect negative electrode materials and discharge product gases. The system provided by the embodiment of the present application can fully distribute the reaction raw materials evenly, so that each reaction raw material is fully contacted and reacted, thereby better regulating the growth orientation of carbon nanotubes.

[0091] Further, based on the above embodiment, the gas pulse distribution device 300 is described in detail, such as Figure 2 and Figure 3 As shown, the gas pulse distribution device 300 includes a reactor 370, a plurality of brackets 360 and a plurality of honeycomb distribution plates 320; the plurality of brackets 360 are arranged in the reactor 370 to divide the reactor 370 into a plurality of reaction chambers 310, and the plurality of reaction chambers 310 are interconnected; the plurality of honeycomb distribution plates 320 are respectively arranged on the plurality of brackets 360, and a plurality of through holes are arranged on the honeycomb distribution plates 320; a gas inlet 350 is also arranged at the bottom end of the reactor 370, and the gas inlet 350 is used to introduce a carrier gas.

[0092] In order to optimize the gas distribution and fluidization effect of the reaction materials during the reaction process, the reactor 370 is provided with a plurality of brackets 360 and a plurality of honeycomb distribution plates 320. The plurality of brackets 360 are used to support and fix the plurality of honeycomb distribution plates 320. The plurality of honeycomb distribution plates 320 divide the interior of the gas pulse distribution device 300 into a plurality of independent but interconnected reaction chambers 310, so that multiple reaction environments are formed inside the device, thereby improving the overall reaction efficiency.

[0093] Multiple brackets 360 play a supporting and partitioning role in the reactor 370, which not only provides structural stability for the device, but also ensures effective connectivity between the various reaction chambers 310, allowing the carrier gas and reaction materials to flow freely between different reaction chambers, thereby promoting uniform distribution and sufficient reaction of the materials.

[0094] One or more honeycomb distribution plates 320 can be installed on each bracket 360. The distribution plate is covered with multiple through holes, such as rheological through holes 321. The geometric structure of the honeycomb distribution plate 320 can effectively adjust the direction and rate of gas flow. The setting of the through holes not only enhances the uniformity of gas distribution, but also improves the fluidization degree of the reactants, ensuring sufficient contact between the reactants and the carrier gas.

[0095] In addition, the bottom of the reactor 370 is provided with a gas inlet 350, which is used to introduce carrier gas. By precisely controlling the flow rate and pressure of the gas inlet 350, the distribution and flow state of the gas inside the device can be further optimized, ensuring the efficient operation of the reactor 370 under different operating conditions and being able to adapt to a variety of reaction requirements. For example, a larger gas velocity at the bottom of the reactor 370 is conducive to full fluidization of the particles, while a smaller gas velocity at the top can extend the residence time of the material. In combination with the honeycomb distribution plate and the directional micropores, uniform distribution of the reducing atmosphere and sufficient gas-solid contact can be achieved.

[0096] For further reference, Figure 2 The gas pulse distribution device 300 also includes a temperature sensor 330 and a gas preheater 340; the temperature sensor 330 is arranged on one side of the reactor 370, and the temperature sensor 330 is used to detect the temperature inside the reactor 370; the gas preheater 340 is arranged on one side of the reactor 370 and close to the gas inlet 350 end, and the gas preheater 340 is used to adjust the temperature inside the reactor 370.

[0097] In order to ensure that the reduction reaction in the gas pulse distribution device 300 is sufficient, a temperature sensor 330 and a gas preheater 340 are provided on the gas pulse distribution device 300 to perform temperature monitoring and regulation.

[0098] The temperature sensor 330 is disposed on one side of the gas pulse distribution device 300, and is mainly used to detect the temperature change inside the temperature sensor 330 in real time. Through accurate temperature monitoring, the temperature sensor 330 can provide real-time temperature data, so that the operator can understand the thermal state inside the device in time, and ensure the stability and safety of the reaction.

[0099] The gas preheater 340 is disposed at the side end of the gas pulse distribution device 300, near the gas inlet 350, for the purpose of preheating the carrier gas before it enters the temperature sensor 330, so as to ensure that the gas has reached the required temperature when entering the reaction chamber, which not only helps to increase the reaction rate, but also ensures the consistency and controllability of the reaction conditions. By adjusting the heating power of the gas preheater 340, the temperature in the gas pulse distribution device 300 can be accurately controlled, thereby optimizing the reaction conditions.

[0100] The combined use of the temperature sensor 330 and the gas preheater 340 enables the gas pulse distribution device 300 to have a high degree of temperature control capability, thereby improving the efficiency of the reaction and the quality of the product, and providing a more ideal operating environment for complex chemical reactions.

[0101] For further reference, Figure 4 The vortex control device 200 includes a vortex controller 210, a shell 220 and a vortex intensity detector 230; the vortex controller 210 is arranged in the shell 220, and the bottom end of the vortex controller 210 is connected to the gas pulse distribution device 300; an vortex intensity detector 230 is arranged on one side of the vortex controller 210, and the vortex intensity detector 230 is used for the vortex intensity in the shell 220; a connecting port is also arranged at the bottom of the shell 220, and the connecting port is used to introduce the carbon source gas.

[0102] The vortex controller 210 is disposed inside the housing 220 of the vortex control device 200, and its bottom end is connected to the gas pulse distribution device 300, so that the reaction raw materials introduced from the gas pulse distribution device 300 can smoothly enter the vortex control device 200. The vortex controller 210 can effectively adjust the flow path and speed of the gas, form a stable and strong vortex, and enhance the mixing and contact between the reactants and the carbon source gas, thereby improving the reaction efficiency and product quality.

[0103] The eddy current intensity detector 230 is arranged on one side of the eddy current controller 210, and can monitor the eddy current intensity inside the eddy current control device 200 in real time and provide accurate eddy current intensity data. The eddy current intensity detector 230 enables the operator to understand and adjust the state of the eddy current in time to ensure the stability and controllability of the reaction process.

[0104] A connecting port is provided at the bottom end of the shell 220 for introducing the carbon source gas. The gas flow rate of the connecting port can be controlled, which can further optimize the gas mixing and reaction conditions in the vortex control device 200, ensure the effective introduction and full utilization of the carbon source gas, and promote the reaction.

[0105] For further reference, Figure 4The vortex controller 210 includes a gas outlet 211 and a spiral guide groove 214; the gas outlet 211 is arranged at the top of the vortex controller 210 and is connected to the electrostatic separation device 100; the spiral guide groove 214 is arranged on the vortex controller 210, and the spiral guide groove 214 is used to guide the carrier gas and the pretreatment product to react with the carbon nanotubes and the carbon source gas, thereby increasing the reaction time and allowing them to fully react; a plurality of gas nozzles 212 and a plurality of vortex control blades 213 are arranged on the side wall of the vortex controller 210; the plurality of gas nozzles 212 are used to spray the carbon source gas into the vortex control device 200, so that the vortex control device 200 generates a rotating airflow, and the plurality of vortex control blades 213 control the vortex intensity and direction by adjusting their angles.

[0106] As one of the important components in the vortex control device 200, the vortex controller 210 is mainly used to optimize the gas flow and reaction process to improve the reaction efficiency and product quality. The vortex controller 210 is provided with a gas outlet 211, a spiral guide groove 214, a plurality of gas nozzles 212 and a vortex control blade 213. The gas outlet 211 is located at the top of the vortex controller 210 and is connected to the electrostatic separation device 100. The reacted gas and product can be smoothly transferred from the vortex control device 200 to the electrostatic separation device 100 for further processing.

[0107] The spiral guide groove 214 is used to guide the flow path of the carrier gas and the pretreatment product inside the device, wherein, for example, carbon nanotubes can be placed in the spiral guide groove 214. When the carbon source gas and the pretreatment product (silicon powder loaded with a catalyst) are guided by the spiral guide groove 214 to form a spiral flow and can fully react with the reactants such as carbon nanotubes, the contact time between the pretreatment product and the carbon nanotubes and the carbon source gas is increased, thereby promoting full reaction, which not only improves the reaction efficiency, but also ensures the high purity of the reaction product.

[0108] A plurality of gas nozzles 212 are provided on the side wall of the vortex controller 210, and these nozzles are used to spray carbon source gas into the vortex control device 200. By accurately controlling the gas flow rate and injection angle of the nozzle, a strong rotating airflow can be generated inside the device, the mixing and contact of the reactants are enhanced, and the reaction efficiency is further improved. In addition, the vortex control blade 213 can accurately control the intensity and direction of the vortex by adjusting its angle, so that the vortex controller 210 can adapt to different reaction conditions and requirements, and provide greater operational flexibility. By adjusting the angle of the vortex control blade 213, the gas flow and reaction conditions can be optimized.

[0109] For further reference, Figure 5The electrostatic separation device 100 includes a gas rectifier 110 and a product collector 130; the gas rectifier 110 is arranged at the bottom end of the electrostatic separation device 100 and is connected to the vortex control device 200, and the gas rectifier 110 is used to convert the vortex airflow flowing in from the vortex control device 200 into a laminar airflow; the product collector 130 is arranged at the top end of the electrostatic separation device 100, and the product collector 130 is used to collect negative electrode materials.

[0110] The gas rectifier 110 is located at the bottom of the electrostatic separation device 100 and is connected to the vortex control device 200, and is used to convert the vortex airflow flowing in from the vortex control device 200 into a laminar airflow. Through this conversion, the gas rectifier 110 can significantly reduce the turbulence of the airflow, making the airflow inside the electrostatic separation device 100 more stable and orderly, which not only improves the efficiency of electrostatic separation, but also creates favorable conditions for subsequent product collection.

[0111] The product collector 130 is disposed at the top of the electrostatic separation device 100 and is used to collect reaction products such as negative electrode materials. By controlling the strength and direction of the electrostatic field, the product collector 130 can effectively capture and collect solid particles separated from the airflow, ensuring that the collected products have a high purity. The combined use of the gas rectifier 110 and the product collector 130 enables the electrostatic separation device 100 to have a high degree of separation and collection capabilities, which not only improves the quality of the reaction products, but also effectively reduces energy consumption and system damage, and extends the service life of the system. In addition, by optimizing the airflow state and the control of the electrostatic field, the electrostatic separation device 100 can adapt to changes in different reaction conditions and product characteristics, providing greater operational flexibility and efficiency.

[0112] For further reference, Figure 5 An annular electrode plate 120 is disposed on at least one side of the electrostatic separation device; the annular electrode plate 120 is used to separate the product gas and the negative electrode material, so that the product gas is discharged outside the electrostatic separation device 100.

[0113] The multiple annular electrode plates 120 are mainly used to utilize the electrostatic force field to achieve effective separation of the product gas and the negative electrode material. When the mixed gas flow enters the electrostatic separation device 100, the multiple electrode plates can apply different electrostatic forces to particles of different properties by applying an electric field. Due to the different charge characteristics of the negative electrode material and the product gas, the annular electrode plate 120 can effectively separate them. Under the action of the electrostatic force, the negative electrode material is attracted and deposited near the electrode plate, while the product gas is discharged to the outside of the electrostatic separation device 100 under the promotion of the electric field, which improves the separation efficiency, ensures the rapid discharge of the product gas, and reduces the gas residence time inside the device.

[0114] The present application also provides a method for preparing a negative electrode material for a battery, using any of the above embodiments, such as Figure 6 As shown, the following steps are included:

[0115] S601, adding silicon powder loaded with catalyst precursor into the gas pulse distribution device 300, setting the reaction temperature and reaction pressure to generate a pre-treated product; and introducing a carrier gas to allow the pre-treated product to flow into the vortex control device 200.

[0116] S602 , introducing a carbon source gas into the vortex control device 200 to allow the pre-treated product to react with the carbon nanotubes to generate a product gas and a negative electrode material.

[0117] S603, discharging the product gas flowing into the electrostatic separation device 100, and collecting the negative electrode material, that is, the silicon / carbon nanotube composite material.

[0118] Furthermore, the carrier gas is selected from one of argon, nitrogen or helium or any combination thereof.

[0119] And / or, the carbon source gas is selected from one or any combination of methane, ethylene, ethane, propylene or butene.

[0120] And / or, the reaction temperature is 400-1200° C., and the reaction pressure is 0.1-5 MPa.

[0121] And / or, the catalyst precursor includes a hydroxide corresponding to the transition metal.

[0122] And / or, the particle size of the silicon powder in the negative electrode material is 50 to 200 nm.

[0123] And / or, the diameter of the carbon nanotubes in the negative electrode material is 20 to 80 nm.

[0124] And / or, the length of the carbon nanotubes in the negative electrode material is 5 to 20 μm.

[0125] The embodiment of the present application also provides a negative electrode material, which is obtained by using the preparation method in any of the above embodiments.

[0126] Furthermore, the present application also uses the system provided in the above embodiment to carry out specific implementation of preparing negative electrode materials, namely silicon / carbon nanotube composite materials, and at the same time, performs performance testing on the prepared negative electrode materials.

[0127] Example 1

[0128] This embodiment adopts Figure 1The multi-segment reaction preparation system shown in the figure is made of GH3030 high-temperature alloy with a wall thickness of 8mm, which has good high-temperature strength and oxidation resistance. The reaction system is in a vertical cylindrical shape with a total height of 2000mm and is divided into three functional areas: the gas pulse distribution device is the catalyst reduction area, the vortex control device is the carbon nanotube growth area, and the electrostatic separation device is the product separation area.

[0129] The gas pulse distribution device adopts a conical structure, with an inner diameter of 100mm at the bottom, gradually expanding to 200mm at the top, and a height of 600mm. The device is equipped with three layers of honeycomb gas distribution plates made of high-purity alumina ceramic material. The distribution plate has a hexagonal honeycomb structure, with a single channel side length of 3mm, a wall thickness of 0.8mm, and an opening rate of 15%. The aperture uniformly opened on each layer of the distribution plate is 100μm, with an inclination angle of 15°, forming a rotating flow field.

[0130] The vortex control device adopts a constant diameter cylinder structure with an inner diameter of 200mm and a height of 800mm. The inner wall is provided with a spiral guide groove with a pitch of 100mm, a groove depth of 5mm and a groove width of 10mm. Four sets of adjustable vortex control blades are installed in the area. The blades are made of high temperature resistant stainless steel, with a chrome-plated surface and a blade angle of 30°. Six tangentially arranged secondary airflow nozzles are set with a diameter of 1mm.

[0131] The inner diameter of the electrostatic separation device is expanded to 300mm and the height is 600mm. It is equipped with an electrostatic separator, including 4 pairs of titanium alloy electrode plates arranged in a ring, with an operating voltage of 20kV. The surface of the electrode plate is treated with a special anti-adhesion coating, and the coating material is a polytetrafluoroethylene modified carbon nanotube composite material with a thickness of 50μm. The temperature in this area is controlled at 200±1℃ to prevent product agglomeration.

[0132] The piezoelectric pulse generator installed in the gas pulse distribution device can generate a frequency-adjustable pulse gas flow of 0.5 to 2 Hz. The system includes a gas preheating device, which adopts electric heating and the preheating temperature can reach 800°C. It is equipped with a mass flow meter and a pressure sensor, and is automatically controlled by a PLC system.

[0133] The temperature control of the whole system adopts zoned electric heating, and each zone is equipped with two sets of heating elements with a power density of 5W / cm 2 The temperature control system uses a PLC controller and a K-type thermocouple to achieve a control accuracy of ±1°C. The outer wall of the reactor is coated with a thermally conductive uniform coating made of an alumina-based nanocomposite material with a thickness of 200μm.

[0134] The above system is used to prepare the material, with nano-silicon powder with a particle size of 100nm and loaded with catalyst as raw material, and the composite material is prepared in a multi-segment reaction device. The carrier gas and carbon source gas in the reaction device are argon and methane respectively, the reaction temperature is 900℃, the reaction pressure is 0.1Mpa, and the reaction time is 15min.

[0135] Figure 7 This is a scanning electron microscope photograph of the silicon / carbon nanotube composite negative electrode material prepared in Example 1 of the present invention. The carbon nanotubes in the obtained product grow evenly, with an average length of 2-3μm, and are intertwined and entangled on the surface of the silicon powder, and the directional growth rate reaches more than 85%.

[0136] like Figure 8 As shown, after the electrode performance of the silicon / carbon nanotube composite negative electrode material prepared in this embodiment was measured by a charge and discharge tester, the first discharge specific capacity reached 3503mAh / g, the first coulomb efficiency reached 90.0%, and after 600 cycles at a current of 1A / g, the capacity retention rate was 89%.

[0137] Example 2

[0138] The system used in this embodiment can refer to the embodiment 1, except that:

[0139] The gas pulse distribution device adopts a conical structure, with an inner diameter of 100mm at the bottom, an inner diameter gradually expanding to 200mm at the top, and a height of 600mm. Three layers of honeycomb gas distribution plates are set in this area, made of high-purity alumina ceramic material. The distribution plate has a hexagonal honeycomb structure, with a single channel side length of 3mm, a wall thickness of 0.8mm, and an opening rate of 20%. The pore size uniformly opened on each layer of the distribution plate is 100μm, with an inclination angle of 15°, forming a rotating flow field. The rest of the device is consistent with Example 1.

[0140] The above system is used to prepare the material, with nano-silicon powder with a particle size of 100nm and loaded with catalyst as raw material, and the composite material is prepared in a multi-segment reaction device. The carrier gas and carbon source gas in the reaction device are argon and methane respectively, the reaction temperature is 900℃, the reaction pressure is 0.1Mpa, and the reaction time is 15min.

[0141] The silicon / carbon nanotube composite negative electrode material prepared in this embodiment was tested for electrode performance by a charge and discharge tester. The first discharge specific capacity reached 3610 mAh / g, the first coulomb efficiency reached 91.6%, and after 600 cycles at a current of 1 A / g, the capacity retention rate was 87.6%.

[0142] Example 3

[0143] The system used in this embodiment can refer to the embodiment 1, except that:

[0144] The gas pulse distribution device adopts a conical structure, with an inner diameter of 100mm at the bottom, an inner diameter gradually expanding to 200mm at the top, and a height of 600mm. Three layers of honeycomb gas distribution plates are set in this area, made of high-purity alumina ceramic material. The distribution plate has a hexagonal honeycomb structure, with a single channel side length of 3mm, a wall thickness of 0.8mm, and an opening rate of 20%. The pore size uniformly opened on each layer of the distribution plate is 150μm, with an inclination angle of 15°, forming a rotating flow field. The rest of the device is consistent with Example 1.

[0145] The above system is used to prepare the material, with nano-silicon powder with a particle size of 100nm and loaded with catalyst as raw material, and the composite material is prepared in a multi-segment reaction device. The carrier gas and carbon source gas in the reaction device are argon and methane respectively, the reaction temperature is 900℃, the reaction pressure is 0.1Mpa, and the reaction time is 15min.

[0146] The silicon / carbon nanotube composite negative electrode material prepared in this embodiment was tested for electrode performance by a charge and discharge tester, and the first discharge specific capacity reached 3586mAh / g, the first coulomb efficiency reached 91.8%, and after 600 cycles at a current of 1A / g, the capacity retention rate was 88.5%.

[0147] Example 4

[0148] The device used in this embodiment can refer to the embodiment 1, the difference is:

[0149] The vortex control device adopts a constant diameter cylinder structure with an inner diameter of 200mm and a height of 800mm. A spiral guide groove is set on the inner wall with a pitch of 100mm, a groove depth of 5mm and a groove width of 10mm. Four sets of adjustable vortex control blades are installed in the area. The blades are made of high-temperature resistant stainless steel, chrome-plated on the surface, and the blade angle is 45°. Six tangentially arranged secondary airflow nozzles are set with a diameter of 1mm. The rest of the device is consistent with Example 1.

[0150] The above system is used to prepare the material, with nano-silicon powder with a particle size of 100nm and loaded with catalyst as raw material, and the composite material is prepared in a multi-segment reaction device. The carrier gas and carbon source gas in the reaction device are argon and methane respectively, the reaction temperature is 900℃, the reaction pressure is 0.1Mpa, and the reaction time is 15min.

[0151] like Fig. 9 As shown, the silicon / carbon nanotube composite negative electrode material prepared in this embodiment is tested by a charge and discharge tester for electrode performance. The rate performance is as follows Figure 8As shown, the capacities at currents of 0.2, 0.3 and 1 A / g are 3153, 2920 and 2100 mAh / g, respectively. After 500 cycles at a current density of 2 A / g, the capacity retention rate is 91.3%.

[0152] Example 5

[0153] The device used in this embodiment can refer to the embodiment 1, the difference is:

[0154] The vortex control device adopts a constant diameter cylinder structure with an inner diameter of 200mm and a height of 800mm. A spiral guide groove is set on the inner wall with a pitch of 100mm, a groove depth of 5mm and a groove width of 10mm. Four sets of adjustable vortex control blades are installed in the area. The blades are made of high-temperature resistant stainless steel, chrome-plated on the surface, and the blade angle is 45°. Six tangentially arranged secondary airflow nozzles are set with a diameter of 1mm. The rest of the device is consistent with Example 1.

[0155] The above system is used to prepare the material, with nano-silicon powder with a particle size of 100nm and loaded with catalyst as raw material, and the composite material is prepared in a multi-segment reaction device. The carrier gas and carbon source gas in the reaction device are argon and methane respectively, the reaction temperature is 900℃, the reaction pressure is 0.1Mpa, and the reaction time is 15min.

[0156] The silicon / carbon nanotube composite negative electrode material prepared in this embodiment was tested for electrode performance by a charge and discharge tester. The capacities at currents of 0.2, 0.3 and 1 A / g were 3089, 2878 and 2113 mAh / g, respectively. After 500 cycles at a current density of 2 A / g, the capacity retention rate was 92.1%.

[0157] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily required by the present application.

[0158] The various embodiments or implementation methods in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referenced to each other.

[0159] It should be noted that the phrases "in specific implementation", "in some embodiments", "in this embodiment", "exemplarily" and the like mentioned in the specification indicate that the described embodiment may include specific features, structures or characteristics, but not every embodiment may include the specific features, structures or characteristics. In addition, such phrases do not necessarily refer to the same embodiment. In addition, when describing specific features, structures or characteristics in conjunction with an embodiment, it is within the knowledge of those skilled in the art to implement such features, structures or characteristics in conjunction with other embodiments that are explicitly or not explicitly described.

[0160] In general, terms should be understood, at least in part, by the context in which they are used. For example, the term "one or more" as used herein may be used to describe any feature, structure, or characteristic in a singular sense, or may be used to describe a combination of features, structures, or characteristics in a plural sense, depending, at least in part, on the context. Similarly, terms such as "a," "an," or "the" may also be understood to convey singular usage or to convey plural usage, depending, at least in part, on the context.

[0161] It should be easily understood that “on,” “above,” and “over” in the present disclosure should be interpreted in the broadest manner, so that “on” not only means “directly on something,” but also includes the meaning of “on something” with intervening features or layers therebetween, and “above” or “over” not only includes the meaning of “above” or “over,” but also may include the meaning of “above” or “over something” with no intervening features or layers therebetween (i.e., directly on something).

[0162] In addition, spatially relative terms may be used herein for ease of explanation, for example, "below", "below", "below", "above", "above", etc., to describe the relationship of one element or feature relative to other elements or features as shown in the figure. Spatially relative terms are intended to include different orientations of the device in use or operation other than the orientation shown in the drawings. The device may have other orientations (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein may also be interpreted accordingly. In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0163] Furthermore, in the description of the present invention, it should be noted that the terms "front", "rear", etc. indicate positions or positional relationships based on positions or positional relationships, or the positions or positional relationships in which the invention product is usually placed when in use, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used to distinguish descriptions, and cannot be understood as indicating or implying relative importance.

[0164] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0165] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A system for preparing a negative electrode material for a battery, characterized in that: include: An electrostatic separation device (100), a vortex control device (200) and a gas pulse distribution device (300); The electrostatic separation device (100) and the gas pulse distribution device (300) are respectively connected to the vortex control device (200); a carrier gas is introduced into the gas pulse distribution device (300), and a carbon source gas is introduced into the vortex control device (200); The gas pulse distribution device (300) is used to carry out a reduction reaction on silicon powder loaded with a catalyst precursor to generate a pre-treated product; and the carrier gas allows the pre-treated product to enter the vortex control device (200); The vortex control device (200) is used to react the pre-treated product with the carbon nanotubes in the carbon source gas atmosphere, so that the carbon nanotubes grow in situ to generate negative electrode materials and product gas; and the product gas allows the negative electrode material to enter the electrostatic separation device (100); The electrostatic separation device (100) is used to collect the negative electrode material and discharge the product gas.

2. The system according to claim 1, characterized in that The gas pulse distribution device (300) comprises a reactor (370), a plurality of brackets (360) and a plurality of honeycomb distribution plates (320); The multiple supports (360) are arranged in the reactor (370) to divide the reactor (370) into multiple reaction chambers (310), and the multiple reaction chambers (310) are interconnected; The honeycomb distribution plates (320) are respectively arranged on the brackets (360), and a plurality of through holes are arranged on the honeycomb distribution plates (320); a gas inlet (350) is also arranged at the bottom end of the reactor (370), and the gas inlet (350) is used to introduce the carrier gas.

3. The system according to claim 2, characterized in that The gas pulse distribution device (300) further includes a temperature sensor (330) and a gas preheater (340); The temperature sensor (330) is disposed on one side of the reactor (370), and the temperature sensor (330) is used to detect the temperature inside the reactor (370); The gas preheater (340) is disposed on one side of the reactor (370) and close to the bottom end of the reactor (370). The gas preheater (340) is used to adjust the temperature inside the reactor (370).

4. The system according to claim 1, characterized in that The eddy current control device (200) comprises an eddy current controller (210), a housing (220) and an eddy current intensity detector (230); The vortex controller (210) is arranged in the housing (220), and the bottom end of the vortex controller (210) is connected to the gas pulse distribution device (300); the vortex intensity detector (230) is arranged on one side of the vortex controller (210), and the vortex intensity detector (230) is used to detect the vortex intensity in the housing (220); The bottom end of the shell (220) is also provided with a communication port, and the communication port is used to introduce the carbon source gas.

5. The system according to claim 4, characterized in that The vortex controller (210) is provided with a gas outlet (211) and a spiral guide groove (214); The gas outlet (211) is arranged at the top of the vortex controller (210) and is connected to the electrostatic separation device (100); The spiral guide groove (214) is used to guide the carrier gas and the pre-treated product to react with the carbon nanotubes and the carbon source gas, thereby increasing the reaction time to allow them to fully react; A plurality of gas nozzles (212) and a plurality of vortex control blades (213) are arranged on the side wall of the vortex controller (210); the plurality of gas nozzles (212) are used to spray the carbon source gas into the shell (220) so as to generate a rotating airflow in the shell (220); and the plurality of vortex control blades (213) control the intensity and direction of the vortex by adjusting the angle of the vortex control blades (213).

6. The system according to claim 1, characterized in that The electrostatic separation device (100) comprises a gas rectifier (110) and a product collector (130); The gas rectifier (110) is connected to the vortex control device (200), and the gas rectifier (110) is used to convert the vortex airflow flowing in from the vortex control device (200) into a laminar airflow; The product collector (130) is arranged at the top of the electrostatic separation device (100), and the product collector (130) is used to collect the negative electrode material.

7. The system according to claim 6, characterized in that An annular electrode plate (120) is provided on at least one side of the electrostatic separation device (100); The annular electrode plate (120) is used to separate the product gas and the negative electrode material so that the product gas can be discharged.

8. A method for preparing a negative electrode material for a battery, using the system according to any one of claims 1 to 7, characterized in that: The steps include: Adding silicon powder loaded with a catalyst precursor into a gas pulse distribution device (300), setting a reaction temperature and a reaction pressure, and generating the pretreated product; and introducing a carrier gas to allow the pre-treated product to flow into the vortex control device (200); A carbon source gas is introduced into the vortex control device (200) to allow the pre-treated product to react with the carbon nanotubes added to the vortex control device (200) to generate the product gas and the negative electrode material; The product gas flowing into the electrostatic separation device (100) is discharged, and the negative electrode material, namely the silicon / carbon nanotube composite material, is collected.

9. The method according to claim 8, characterized in that The carrier gas is selected from one or more of argon, nitrogen or helium in any proportion; And / or, the carbon source gas is selected from one or any combination of methane, ethylene, ethane, propylene or butene; And / or, the reaction temperature is 400-1200° C., and the reaction pressure is 0.1-5 MPa; And / or, the catalyst precursor includes a hydroxide corresponding to a transition metal; And / or, the diameter of the carbon nanotubes in the negative electrode material is 20 to 80 nm; And / or, the length of the carbon nanotubes in the negative electrode material is 5 to 20 μm; And / or, the particle size of the silicon powder in the negative electrode material is 50 to 200 nm.

10. A negative electrode material, characterized in that: The method according to claim 8 or 9 is used for preparation.

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