Silicon-carbon powder, manufacturing equipment thereof, and dispersion adsorption process based on silicon-carbon powder

Abstract

The application provides a silicon-carbon powder, a manufacturing device thereof, and a dispersion adsorption process based on the silicon-carbon powder. The dispersion adsorption process based on the silicon-carbon powder comprises the following steps: obtaining porous carbon powder; introducing a modified gas into the porous carbon powder for fluidization treatment, wherein the modified gas at least comprises a silane compound and a hydrocarbon compound, and the flow rate of the modified gas is 10-200 sccm; and performing plasma treatment on the modified gas, and introducing the plasma gas into the porous carbon powder, so that the porous carbon powder and the plasma gas can be uniformly dispersed and mixed, the plasma power is 100-4000 W, the discharge voltage is 500-5000 V, the discharge current is 0.2-3 A, and the temperature is 50-400 DEG C. The dispersion adsorption process based on the silicon-carbon powder can better optimize the dispersion uniformity of the porous carbon and the plasma gas, and further improve the doping and coating uniformity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas and solid mixing, and in particular to a silicon-carbon powder, a manufacturing device thereof, and a dispersion adsorption process based on the silicon-carbon powder. BACKGROUND

[0002] Lithium battery active material, wherein there is more doping and coating of substances, such as the invention patent application with the application number CN202210619600.0, which is the preparation of positive material lithium iron manganese phosphate. Specifically, the surface of the lithium iron manganese phosphate material is treated by plasma to perform non-metal doping and coating. The treatment efficiency of doping and coating is high, and the performance of the lithium iron manganese phosphate is not affected. However, since the lithium iron manganese phosphate is a powder, there is agglomeration between the microparticles and accumulation between the particles, which causes insufficient mixing of the lithium iron manganese phosphate and the plasma gas, and thus the local surface of the lithium iron manganese phosphate does not undergo plasma treatment, resulting in poor uniformity of non-metal doping and coating of the lithium iron manganese phosphate. Especially for the preparation of lithium battery negative material silicon-carbon powder, the smaller the porous carbon particle size, the more difficult it is to disperse, which further affects the dispersion uniformity of the porous carbon and the plasma gas, and further affects the uniform doping and coating of silicon of the porous carbon, and has a great influence on the electrochemical performance of the lithium battery negative material silicon-carbon powder. SUMMARY

[0003] The purpose of the present application is to overcome the deficiencies in the prior art, and to provide a silicon-carbon powder, a manufacturing device thereof, and a dispersion adsorption process based on the silicon-carbon powder, which can better optimize the dispersion uniformity of the porous carbon and the plasma gas, and further improve the doping and coating uniformity.

[0004] The purpose of the present application is achieved by the following technical solutions:

[0005] A dispersion adsorption process based on a silicon-carbon powder, comprising the following steps:

[0006] Obtaining a porous carbon powder;

[0007] Introducing a modification gas into the porous carbon powder for fluidization treatment, wherein the modification gas at least includes a silane compound and a hydrocarbon compound, and the flow rate of the modification gas is 10sccm-200sccm;

[0008] Performing plasma treatment on the modification gas, and introducing the plasma gas into the porous carbon powder, so that the porous carbon powder and the plasma gas can be uniformly dispersed and mixed. The plasma power is 100W-4000W, the discharge voltage is 500V-5000V, the discharge current is 0.2A-3A, and the temperature is 50℃-400℃.

[0009] In one embodiment, the hydrocarbon compound is at least one of methane, ethane, and acetylene.

[0010] In one of the embodiments, the silane compound is monosilane and / or disilane.

[0011] In one of the embodiments, the particle size distribution of the porous carbon powder is 0.2 μm ~ 12 μm, and the D50 is 1 μm ~ 4 μm.

[0012] In one of the embodiments, the pore size distribution of the porous carbon powder is 0.2 nm ~ 3.5 nm, the pore volume is 0.25 cm 3 / g ~ 1 cm 3 / g, and the porosity is 60% ~ 95%.

[0013] In one of the embodiments, the specific surface area of the porous carbon powder is 1000 m 2 / g ~ 2500 m 2 / g.

[0014] In one of the embodiments, the bulk density of the porous carbon powder is 0.01 cm 3 / g ~ 0.2 cm 3 / g.

[0015] In one of the embodiments, before the step of passing the modification gas through the porous carbon powder for fluidization treatment, and after the step of obtaining the porous carbon powder, the dispersion adsorption process based on the silicon-carbon powder further comprises the following steps:

[0016] Passing inert gas through the porous carbon powder for fluidization treatment;

[0017] Plasma treating the inert gas.

[0018] In one of the embodiments, passing inert gas through the porous carbon powder for fluidization treatment, the flow rate of the inert gas is 5 sccm ~ 200 sccm.

[0019] In one of the embodiments, plasma treating the inert gas, the plasma power is 100 W ~ 1500 W, the discharge voltage is 500 V ~ 5000 V, the discharge current is 0.2 A ~ 3 A, and the temperature is 50 ℃ ~ 400 ℃.

[0020] In one of the embodiments, the modification gas further comprises inert gas.

[0021] In one of the embodiments, the inert gas is nitrogen and / or argon.

[0022] In one of the embodiments, plasma treating the modification gas, specifically comprising the following steps:

[0023] The modification gas is subjected to first-stage plasma treatment, wherein the flow rate of the modification gas is 10-50 sccm; the plasma power is 100-500 W, the discharge voltage is 500-1500 V, the discharge current is 0.2-0.8 A, and the temperature is 50-200℃;

[0024] The modification gas is subjected to second-stage plasma treatment, wherein the flow rate of the modification gas is 100-200 sccm; the plasma power is 2000-4000 W, the discharge voltage is 2500-5000 V, the discharge current is 1-3 A, and the temperature is 300-400℃;

[0025] The modification gas is subjected to third-stage plasma treatment, wherein the flow rate of the modification gas is 50-100 sccm; the plasma power is 500-2000 W, the discharge voltage is 1500-2500 V, the discharge current is 0.5-1.5 A, and the temperature is 100-300℃.

[0026] A silicon-carbon powder preparation device for implementing the dispersion adsorption process based on silicon-carbon powder according to any one of the above embodiments, the silicon-carbon powder preparation device comprising:

[0027] A powder fluidization system;

[0028] A feeding system in communication with the powder fluidization system, the feeding system being configured to add porous carbon powder to obtain the porous carbon powder and feed the porous carbon powder into the powder fluidization system;

[0029] A gas source system in communication with the powder fluidization system to introduce a modification gas into the porous carbon powder for fluidization treatment;

[0030] A plasma discharge system in communication with the powder fluidization system to perform plasma treatment on the modification gas;

[0031] A control system electrically connected to the gas source system and the plasma discharge system, respectively, to control the flow rate of the plasma gas, and the plasma power, the discharge voltage, the discharge current, and the temperature;

[0032] A discharging system in communication with the powder fluidization system to receive the porous carbon powder output from the powder fluidization system.

[0033] A silicon-carbon powder prepared by the silicon-carbon powder preparation device according to any one of the above embodiments.

[0034] Compared with the prior art, the present application has at least the following advantages: the dispersion adsorption process based on the silicon-carbon powder of the present application introduces a modified gas into the porous carbon powder for fluidization treatment, and uses a silane compound and a hydrocarbon compound to perform plasma surface doping and coating on the surface of the porous carbon powder, so as to promote the flow rate of the modified gas to be 10-200 sccm, reduce the agglomeration between the porous carbon powder particles, and better ensure the uniform dispersion of the porous carbon powder, which is conducive to the uniform dispersion of the plasma gas on the entire surface of the porous carbon powder particles and the full action. Then, the modified gas is subjected to plasma treatment, the plasma power is 100-4000 W, the discharge voltage is 500-5000 V, the discharge current is 0.2-3 A, and the temperature is 50-400 DEG C. On the basis of improving the uniform dispersion between the porous carbon powder particles, the plasma gas is introduced into the porous carbon powder, which effectively improves the uniform distribution of the plasma gas on the surface of the porous carbon powder particles, and further improves the uniform collision of the plasma gas on the surface of the porous carbon powder particles, so as to completely dope and coat silicon and carbon on the surface of the porous carbon powder, that is, silicon and carbon are dispersed and laid on the surface of the porous carbon powder, which effectively improves the doping and coating uniformity of the formed silicon-carbon powder, and improves the electrochemical performance of the lithium negative electrode material silicon-carbon powder. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0036] Figure 1 Flow chart of the dispersion adsorption process based on the silicon-carbon powder of an embodiment of the present application;

[0037] Figure 2 Structural schematic diagram of the production equipment of the silicon-carbon powder of an embodiment of the present application;

[0038] Figure 3 Transmission electron microscope image of the silicon-carbon powder obtained in Example 2. DETAILED DESCRIPTION

[0039] In order to facilitate the understanding of the present application, the following will comprehensively describe the present application with reference to the related drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be realized in many different forms, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0040] It should be understood that when an element as a layer, region or plate is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. In addition, it should be understood that when an element is referred to as being "connected" to or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements can be present. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0042] The application provides a dispersion adsorption process based on silicon carbon powder. The dispersion adsorption process based on silicon carbon powder comprises the following steps: obtaining porous carbon powder; introducing a modified gas into the porous carbon powder for fluidization treatment, wherein the modified gas comprises at least a silane compound and a hydrocarbon compound, and the flow rate of the modified gas is 10-200 sccm; and performing plasma treatment on the modified gas, and introducing the plasma gas into the porous carbon powder, so that the porous carbon powder and the plasma gas can be uniformly dispersed and mixed, the plasma power is 100-4000 W, the discharge voltage is 500-5000 V, the discharge current is 0.2-3 A, and the temperature is 50-400 DEG C.

[0043] The dispersion adsorption process based on the silicon-carbon powder disclosed in the above embodiment introduces the modified gas into the porous carbon powder for fluidization treatment, and uses silane compound and hydrocarbon compound to perform plasma surface doping and coating on the surface of the porous carbon powder, so as to make the flow rate of the modified gas 10-200 sccm, reduce the agglomeration between the porous carbon powder particles, better ensure the uniform dispersion of the porous carbon powder, and facilitate the uniform dispersion of the plasma gas on the entire surface of the porous carbon powder particles and the full action. Then, the modified gas is subjected to plasma treatment, the plasma power is 100-4000 W, the discharge voltage is 500-5000 V, the discharge current is 0.2-3 A, and the temperature is 50-400 ℃. On the basis of improving the uniform dispersion between the porous carbon powder particles, the plasma gas is introduced into the porous carbon powder, which effectively improves the uniform distribution of the plasma gas on the surface of the porous carbon powder particles, and further improves the uniform collision of the plasma gas on the surface of the porous carbon powder particles, so as to completely dope and coat silicon and carbon on the surface of the porous carbon powder, i.e. silicon and carbon are dispersed and laid on the surface of the porous carbon powder, which effectively improves the uniformity of doping and coating of the formed silicon-carbon powder, and improves the electrochemical performance of the lithium negative electrode material silicon-carbon powder.

[0044] In order to better understand the dispersion adsorption process based on the silicon-carbon powder of the present application, the dispersion adsorption process based on the silicon-carbon powder of the present application is further explained as follows:

[0045] Please refer to Figure 1 The dispersion adsorption process based on the silicon-carbon powder of one embodiment includes the following steps:

[0046] S100, obtaining porous carbon powder. It can be understood that the smaller the particle size of the porous carbon powder, the greater the agglomeration strength, which makes it more difficult for the porous carbon powder to be uniformly dispersed, i.e. there are more porous carbon powder particles aggregated together, which makes the surface of the porous carbon powder particles be shielded, and further makes it more difficult for the formed plasma gas to be uniformly dispersed on the surface of each porous carbon powder particle, and further makes the dispersion uniformity of the porous carbon powder particles and the plasma gas poor, which causes the plasma gas to collide only locally on the surface of the porous carbon powder particles, and makes the uniformity of the groups carried by the plasma gas dispersed and attached on the surface of the porous carbon powder poor, i.e. the doping and coating uniformity of the porous carbon powder is affected, and further has a great influence on the electrochemical performance of the lithium negative electrode material silicon-carbon powder. Therefore, the present application obtains the porous carbon powder to improve the uniformity of the groups carried by the plasma gas dispersed and attached on the surface of the porous carbon powder, and further improve the electrochemical performance of the lithium negative electrode material silicon-carbon powder.

[0047] S200, a modification gas is introduced into the porous carbon powder for fluidization treatment, the modification gas at least includes a silane compound and a hydrocarbon compound, and the flow rate of the modification gas is 10-200sccm. It can be understood that the surface of the porous carbon powder is doped and coated by using the silane compound and the hydrocarbon compound, so that the surface of the porous carbon is doped and coated with silicon and carbon, and the flow rate of the modification gas is 10-200sccm, which can better ensure the uniform dispersion of the porous carbon powder, thereby reducing the agglomeration between the porous carbon powder particles, and facilitating the uniform dispersion of the plasma gas on the entire surface of the porous carbon powder particles and sufficient action. Further, the modification gas further includes an inert gas. Further, the inert gas is nitrogen and / or argon.

[0048] S300, the modification gas is subjected to plasma treatment, and the plasma gas is introduced into the porous carbon powder, so that the porous carbon powder and the plasma gas can be uniformly dispersed and mixed, the plasma power is 100-4000W, the discharge voltage is 500-5000V, the discharge current is 0.2-3A, and the temperature is 50-400℃. It can be understood that on the basis of fluidizing the porous carbon powder and reducing the agglomeration of the porous carbon powder particles, the plasma gas is introduced into the porous carbon powder, which effectively improves the uniform distribution of the plasma gas on the surface of the porous carbon powder particles, and further improves the uniform collision of the plasma gas on the surface of the porous carbon powder particles to completely dope and coat the surface of the porous carbon powder with silicon and carbon, i.e. silicon and carbon are dispersed and laid on the surface of the porous carbon powder, which effectively improves the uniformity of the doping and coating of the formed silicon-carbon powder.

[0049] The dispersion adsorption process based on the silicon-carbon powder, in which the modified gas is introduced into the porous carbon powder for fluidization treatment, uses silane compounds and hydrocarbon compounds to perform plasma surface doping and coating on the surface of the porous carbon powder, and the flow rate of the modified gas is 10-200sccm, which reduces the agglomeration between the porous carbon powder particles, better ensures the uniform dispersion of the porous carbon powder, and is conducive to the uniform dispersion of the plasma gas on the entire surface of the porous carbon powder particles and the full action. Then, the modified gas is subjected to plasma treatment, the plasma power is 100-4000W, the discharge voltage is 500-5000V, the discharge current is 0.2-3A, and the temperature is 50-400℃. On the basis of improving the uniform dispersion between the porous carbon powder particles, the plasma gas is introduced into the porous carbon powder, which effectively improves the uniform distribution of the plasma gas on the surface of the porous carbon powder particles, and further improves the uniform collision of the plasma gas on the surface of the porous carbon powder particles, so that the surface of the porous carbon powder is completely doped and coated with silicon and carbon, i.e. silicon and carbon are dispersed and laid on the surface of the porous carbon powder, which effectively improves the doping and coating uniformity of the formed silicon-carbon powder, and improves the electrochemical performance of the lithium negative electrode material silicon-carbon powder.

[0050] In one embodiment, the hydrocarbon compound is at least one of methane, ethane and acetylene. Further, the silane compound is monosilane and / or disilane.

[0051] In one embodiment, before the step of introducing the modified gas into the porous carbon powder for fluidization treatment, and after the step of obtaining the porous carbon powder, the dispersion adsorption process based on the silicon-carbon powder further comprises the following steps:

[0052] Introducing inert gas into the porous carbon powder for fluidization treatment;

[0053] Further, the inert gas is subjected to plasma treatment, and the treatment time is 10-20min. Further, the treatment is implemented for 15min.

[0054] It can be understood that, before the plasma surface doping and coating of the silane compound and the hydrocarbon compound on the surface of the porous carbon powder, the inert gas is used to fluidize the porous carbon powder, so that the dispersion effect between the porous carbon powder particles is improved, and the inert gas is subjected to plasma treatment to form e -The collision of active particles with the surface of porous carbon powder promotes the enrichment and homogenization of active sites on the surface of the porous carbon powder. This results in a uniform amount of plasma gas being consumed by collisions on the surface of the porous carbon powder particles during further surface doping and coating with silane compounds and hydrocarbon compounds. Furthermore, the flow rate of the modification gas ensures that the plasma gas concentration on the surface of the porous carbon powder particles remains uniform after plasma consumption and replenishment. This avoids local inconsistencies in the plasma gas concentration on the surface of the porous carbon powder particles, enabling the surface of the porous carbon powder particles to uniformly disperse and adhere a doped and coated layer structure of uniform thickness. This further improves the doping and coating uniformity of silicon-carbon powder and enhances the electrochemical performance of silicon-carbon powder as a lithium battery anode material.

[0055] In one embodiment, an inert gas is introduced into the porous carbon powder for fluidization treatment. The flow rate of the inert gas is 5 sccm to 200 sccm, which effectively ensures the uniform dispersion of the porous carbon powder particles.

[0056] In one embodiment, the inert gas is subjected to plasma treatment. The plasma power supply has a power of 100W~1500W, a discharge voltage of 500V~5000V, a discharge current of 0.2A~3A, and a temperature of 50℃~400℃. Matching the flow rate of the inert gas, it can effectively generate e. - The active particles are rapidly and uniformly distributed on the outer periphery of the porous carbon powder particles, thus ensuring better dispersion uniformity of the porous carbon powder and the plasma gas. Furthermore, the inert gas is nitrogen and / or argon.

[0057] In one embodiment, the volume ratio of the silane compound, the hydrocarbon compound, and the inert gas is (0.8~1.5):(0.8~1.5):1. Further, the volume ratio of the silane compound, the hydrocarbon compound, and the inert gas is 1:1:1.

[0058] In one embodiment, the porous carbon powder has a particle size distribution of 0.2μm to 12μm and a D50 of 1μm to 4μm, which meets the particle size requirements of silicon-carbon powder for lithium battery anode materials. In addition, the flow rate of the modification gas is 10sccm to 200sccm, which better ensures the uniform dispersion between the particles of the porous carbon powder.

[0059] In one embodiment, the porous carbon powder has a pore size distribution of 0.2 nm to 3.5 nm and a pore volume of 0.25 cm³. 3 / g~1cm 3 / g, with a porosity of 60%~95%. Furthermore, the specific surface area of ​​the porous carbon powder is 1000 m² / g. 2 / g~2500m 2 / g. Further, the bulk density of the porous carbon powder is 0.01 cm 3 / g~0.2cm 3 / g, which is conducive to the effective accommodation of silicon and carbon by the porous carbon powder.

[0060] It should be noted that, on the basis of improving the dispersion effect between the porous carbon powder particles and the dispersion effect of the plasma gas on the surface of the porous carbon powder, the activity of the active sites formed on the surface of the porous carbon powder particles is different, i.e., the combination strength with silicon and carbon is different, so that the local plasma gas on the surface of the porous carbon powder particles is easily consumed quickly, and silicon and carbon are doped and coated quickly and in large quantities, and there is a problem of poor uniformity of the thickness of the layer structure formed by silicon and carbon doping and coating, so that the uniformity of the porous carbon powder and the silicon and carbon doping and coating is poor. In order to better realize the dispersion uniformity of silicon and carbon doping and coating on the surface of the porous carbon powder, in one embodiment, the modification gas is subjected to plasma treatment, specifically including the following steps:

[0061] S310, the modification gas is subjected to primary plasma treatment, wherein the flow rate of the modification gas is 10sccm~50sccm; the plasma power is 100W~500W, the discharge voltage is 500V~1500V, the discharge current is 0.2A~0.8A, and the temperature is 50℃~200℃. It can be understood that the plasma power is 100W~500W, the discharge voltage is 500V~1500V, and the discharge current is 0.2A~0.8A, mainly generating silicon active particles with a low concentration, and the combination temperature is 50℃~200℃ and the flow rate of the modification gas is 10sccm~50sccm, so that the surface of the porous carbon powder particles combines the silicon active particles slowly and mildly, reduces the uneven distribution of silicon and carbon caused by the rapid and large combination and adhesion of silicon and carbon on the local active sites of the porous carbon powder, and in view of the difference in combination strength of different active sites of the porous carbon powder, the silicon active particles will gradually combine and adhere, reducing the problem of poor uniformity of the silicon and carbon doping and coating formed on the surface of the porous carbon powder particles caused by the rapid and large local combination and adhesion of silicon and carbon on the surface of the porous carbon powder particles, and better improving the uniformity of the doping and coating of the silicon and carbon powder. Further, the treatment time is 8min~15min. Further, the treatment is realized for 10min.

[0062] S320, performing secondary plasma treatment on the modification gas, wherein the flow rate of the modification gas is 100sccm~200sccm; the plasma power is 2000W~4000W, the discharge voltage is 2500V~5000V, the discharge current is 1A~3A, and the temperature is 300℃~400℃. It can be understood that after the primary plasma treatment, that is, after the uniform formation of the silicon doping and coating layer on the surface of the porous carbon powder particles, the plasma power is then 2000W~4000W, the discharge voltage is 2500V~5000V, and the discharge current is 1A~3A, at which time the silicon active particles and carbon active particles are formed together, combined with the flow rate of the modification gas being 100sccm~200sccm and the temperature being 300℃~400℃, so that the silicon active particles and carbon active particles are quickly and combinedly attached to the surface of the porous carbon powder particles to realize the rapid doping and coating of silicon and carbon, and due to the existence of the silicon doping and coating layer structure in the early stage, the silicon active particles and carbon active particles are relatively uniformly attached to the surface of the porous carbon powder particles, which better ensures the uniformity of the doping and coating of the silicon and carbon powder, that is, the uniform thickening of the doping and coating layer structure on the surface of the porous carbon powder particles is quickly realized. Further, the treatment time is 15min~25min. Further, the treatment time is 20min.

[0063] S330, performing secondary plasma treatment on the modification gas, wherein the flow rate of the modification gas is 100sccm~200sccm; the plasma power is 2000W~4000W, the discharge voltage is 2500V~5000V, the discharge current is 1A~3A, and the temperature is 300℃~400℃. It can be understood that after the primary plasma treatment, that is, after the uniform formation of the silicon doping and coating layer on the surface of the porous carbon powder particles, the plasma power is then 2000W~4000W, the discharge voltage is 2500V~5000V, and the discharge current is 1A~3A, at which time the silicon active particles and carbon active particles are formed together, combined with the flow rate of the modification gas being 100sccm~200sccm and the temperature being 300℃~400℃, so that the silicon active particles and carbon active particles are quickly and combinedly attached to the surface of the porous carbon powder particles to realize the rapid doping and coating of silicon and carbon, and due to the existence of the silicon doping and coating layer structure in the early stage, the silicon active particles and carbon active particles are relatively uniformly attached to the surface of the porous carbon powder particles, which better ensures the uniformity of the doping and coating of the silicon and carbon powder, that is, the uniform thickening of the doping and coating layer structure on the surface of the porous carbon powder particles is quickly realized. Further, the treatment time is 15min~25min. Further, the treatment time is 20min.

[0064] The application also provides a silicon-carbon powder production device for implementing the dispersion adsorption process based on the silicon-carbon powder according to any one of the above embodiments and preparing the silicon-carbon powder. Please refer toFigure 2 The preparation device 10 of the silicon-carbon powder in an embodiment comprises a powder fluidization system 100, a feeding system 200, a gas source system 300, a plasma discharge system 400, a control system (not shown in the figure) and a discharging system 500. The feeding system 200 is in communication with the powder fluidization system 100, and the feeding system 200 is used for adding porous carbon powder to obtain the porous carbon powder and input the porous carbon powder into the powder fluidization system 100. The gas source system 300 is in communication with the powder fluidization system 100, so as to input a modification gas into the porous carbon powder for fluidization treatment. The plasma discharge system 400 is in communication with the powder fluidization system 100, so as to perform plasma treatment on the modification gas. The control system is electrically connected to the gas source system 300 and the plasma discharge system 400 respectively, so as to control the flow rate of the plasma gas, and the power of the plasma power supply, the discharge voltage, the discharge current and the temperature. The discharging system 500 is in communication with the powder fluidization system 100, and the discharging system 500 is used for adding porous carbon powder to accommodate the porous carbon powder output from the powder fluidization system 100.

[0065] The preparation device 10 of the silicon-carbon powder described above effectively realizes the implementation of the dispersion adsorption process based on the silicon-carbon powder, and ensures the effective preparation of the uniformly doped mixed coated silicon-carbon powder.

[0066] The application also provides a silicon-carbon powder prepared by the preparation device of the silicon-carbon powder described in any one of the above embodiments.

[0067] Compared with the prior art, the application has at least the following advantages:

[0068] The silicocarbide powder-based dispersion adsorption process of the present application fluidizes the porous carbon powder by introducing a modification gas, and uses a silane compound and a hydrocarbon compound to perform plasma surface doping and coating on the surface of the porous carbon powder, so as to promote the flow rate of the modification gas to be 10-200 sccm, reduce the agglomeration between the porous carbon powder particles, and better ensure the uniform dispersion of the porous carbon powder, which is conducive to the uniform dispersion of the plasma gas on the entire surface of the porous carbon powder particles and the full action. Then, the modification gas is subjected to plasma treatment, the plasma power is 100-4000 W, the discharge voltage is 500-5000 V, the discharge current is 0.2-3 A, and the temperature is 50-400℃. On the basis of improving the uniform dispersion between the porous carbon powder particles, the plasma gas is introduced into the porous carbon powder, which effectively improves the uniform distribution of the plasma gas on the surface of the porous carbon powder particles, and further improves the uniform collision of the plasma gas on the surface of the porous carbon powder particles, so as to completely dope and coat silicon and carbon on the surface of the porous carbon powder, i.e. silicon and carbon are dispersed and laid on the surface of the porous carbon powder, which effectively improves the doping and coating uniformity of the formed silicocarbide powder, and improves the electrochemical performance of the lithium negative electrode material silicocarbide powder.

[0069] Some specific examples are listed below, and if % is mentioned, it means percentage by weight. It should be noted that the following examples do not exhaust all possible cases, and the materials used in the following examples can be obtained from commercial channels if not otherwise specified.

[0070] Example 1

[0071] The porous carbon powder (D50 of 2 μm, porosity of 80%) is sucked into the feed bin by negative pressure, the feed valve is opened, and the porous carbon powder is transported to the fluidized reactor by automatic feeding;

[0072] The vacuum pump and the gas outlet valve are opened, the inert gas N2 is introduced, the gas flow rate is adjusted to 100 sccm, the plasma power is turned on, the power is adjusted to 1000 W, the discharge voltage is 2500 V, the discharge current is 2 A, the temperature is 250℃, and the treatment time is 15 min;

[0073] The modification gas including N2, silane and methane (volume ratio 1:1:1) is introduced. The modification gas flow rate is adjusted to 10 sccm. The plasma power is adjusted to 500 W, the discharge voltage is 1500 V, the discharge current is 0.8 A, the temperature is 200 ℃, and the treatment time is 6 min. Then the modification gas flow rate is adjusted to 100 sccm, the power is adjusted to 4000 W, the discharge voltage is 5000 V, the discharge current is 3 A, the temperature is 400 ℃, and the treatment time is 15 min. Then the modification gas flow rate is adjusted to 50 sccm, the power is adjusted to 2000 W, the discharge voltage is 2500 V, the discharge current is 1.5 A, the temperature is 300 ℃, and the treatment time is 10 min.

[0074] The plasma power is turned off. The modification gas is replaced by N2. The exhaust valve is closed, and the discharge valve is opened. The silicon-carbon powder is transported to the discharge bin to obtain the finished product.

[0075] Example 2

[0076] The porous carbon powder (D50 is 2 μm, and the porosity is 80%) is sucked into the feeding bin by negative pressure. The feeding valve is opened. The porous carbon powder is transported to the fluidized reactor by automatic feeding.

[0077] The vacuum pump and the exhaust valve are turned on. The inert gas N2 is introduced. The gas flow rate is adjusted to 100 sccm. The plasma power is turned on. The power is adjusted to 1000 W, the discharge voltage is 2500 V, the discharge current is 2 A, the temperature is 250 ℃, and the treatment time is 15 min.

[0078] The modification gas including N2, silane and methane (volume ratio 1:1:1) is introduced. The modification gas flow rate is adjusted to 20 sccm. The plasma power is adjusted to 200 W, the discharge voltage is 800 V, the discharge current is 0.4 A, the temperature is 100 ℃, and the treatment time is 10 min. Then the modification gas flow rate is adjusted to 140 sccm, the power is adjusted to 2800 W, the discharge voltage is 3000 V, the discharge current is 1.8 A, the temperature is 330 ℃, and the treatment time is 20 min. Then the modification gas flow rate is adjusted to 60 sccm, the power is adjusted to 900 W, the discharge voltage is 1800 V, the discharge current is 0.8 A, the temperature is 150 ℃, and the treatment time is 15 min.

[0079] The plasma power is turned off. The modification gas is replaced by N2. The exhaust valve is closed, and the discharge valve is opened. The silicon-carbon powder is transported to the discharge bin to obtain the finished product.

[0080] Example 3

[0081] The porous carbon powder (D50 of 2 μm, porosity of 80%) is sucked into the feeding bin by negative pressure, the feeding valve is opened, and the porous carbon powder is delivered into the fluidized reactor by automatic feeding;

[0082] The vacuum pump and the exhaust valve are opened, the inert gas N2 is introduced, the gas flow rate is adjusted to 100 sccm, the plasma power is adjusted to 1000 W, the discharge voltage is 2500 V, the discharge current is 2 A, the temperature is 250℃, and the treatment time is 15 min;

[0083] The modification gas is introduced, the modification gas includes N2, silane and methane (volume ratio 1:1:1); the modification gas flow rate is adjusted to 35 sccm, the plasma power is adjusted to 350 W, the discharge voltage is 1200 V, the discharge current is 0.6 A, the temperature is 150℃, and the treatment time is 15 min; then the modification gas flow rate is adjusted to 180 sccm, the power is adjusted to 3200 W, the discharge voltage is 3500 V, the discharge current is 2.5 A, the temperature is 360℃, and the treatment time is 25 min; then the modification gas flow rate is adjusted to 80 sccm, the power is adjusted to 2500 W, the discharge voltage is 2200 V, the discharge current is 0.2 A, the temperature is 220℃, and the treatment time is 20 min;

[0084] The plasma power is turned off, the modification gas is replaced by N2, the exhaust valve is closed, the discharge valve is opened, and the silicon-carbon powder is delivered into the discharge bin to obtain the finished product.

[0085] Example 4

[0086] The porous carbon powder (D50 of 2 μm, porosity of 80%) is sucked into the feeding bin by negative pressure, the feeding valve is opened, and the porous carbon powder is delivered into the fluidized reactor by automatic feeding;

[0087] The vacuum pump and the exhaust valve are opened, the inert gas N2 is introduced, the gas flow rate is adjusted to 100 sccm, the plasma power is adjusted to 1000 W, the discharge voltage is 2500 V, the discharge current is 2 A, the temperature is 250℃, and the treatment time is 15 min;

[0088] The modification gas is introduced, and the modification gas includes N2, silane and methane (volume ratio 1:1:1); the flow rate of the modification gas is adjusted to 50 sccm, the plasma power is turned on, the power is adjusted to 100 W, the discharge voltage is 500 V, the discharge current is 0.2 A, the temperature is 50°C, and the treatment time is 6 min; then the flow rate of the modification gas is adjusted to 200 sccm, the power is adjusted to 2000 W, the discharge voltage is 2500 V, the discharge current is 1 A, the temperature is 300°C, and the treatment time is 18 min; then the flow rate of the modification gas is adjusted to 50 sccm, the power is adjusted to 500 W, the discharge voltage is 1500 V, the discharge current is 0.5 A, the temperature is 100°C, and the treatment time is 22 min;

[0089] The plasma power is turned off, the modification gas is replaced with N2, the exhaust valve is closed, the discharge valve is opened, and the silicon-carbon powder is transported to the discharge bin to obtain the finished product.

[0090] Example 5

[0091] The porous carbon powder (D50 is 1 μm, and the porosity is 60%) is sucked into the feeding bin by negative pressure, the feeding valve is opened, and the porous carbon powder is transported to the fluidized reactor by automatic feeding;

[0092] The vacuum pump and the exhaust valve are turned on, the inert gas N2 is introduced, the flow rate is adjusted to 100 sccm, the plasma power is turned on, the power is adjusted to 1000 W, the discharge voltage is 2500 V, the discharge current is 2 A, the temperature is 250°C, and the treatment time is 15 min;

[0093] The modification gas is introduced, and the modification gas includes Ar, silane and ethane (volume ratio 1:1:1); the flow rate of the modification gas is adjusted to 35 sccm, the plasma power is turned on, the power is adjusted to 350 W, the discharge voltage is 1200 V, the discharge current is 0.6 A, the temperature is 150°C, and the treatment time is 8 min; then the flow rate of the modification gas is adjusted to 180 sccm, the power is adjusted to 3200 W, the discharge voltage is 3500 V, the discharge current is 2.5 A, the temperature is 360°C, and the treatment time is 15 min; then the flow rate of the modification gas is adjusted to 80 sccm, the power is adjusted to 2500 W, the discharge voltage is 2200 V, the discharge current is 0.2 A, the temperature is 220°C, and the treatment time is 22 min;

[0094] The plasma power is turned off, the modification gas is replaced with N2, the exhaust valve is closed, the discharge valve is opened, and the silicon-carbon powder is transported to the discharge bin to obtain the finished product.

[0095] Example 6

[0096] The porous carbon powder (D50 of 4 μm, porosity of 95%) is sucked into the feeding bin by negative pressure, the feeding valve is opened, and the porous carbon powder is delivered to the fluidized reactor by automatic feeding;

[0097] The vacuum pump and the exhaust valve are opened, inert gas N2 is introduced, the gas flow rate is adjusted to 100 sccm, the plasma power is adjusted to 1000 W, the discharge voltage is 2500 V, the discharge current is 2 A, the temperature is 250℃, and the treatment time is 15 min;

[0098] The modification gas is introduced, the modification gas includes Ar, silane and acetylene (volume ratio 1:1:1), the modification gas flow rate is adjusted to 35 sccm, the plasma power is adjusted to 350 W, the discharge voltage is 1200 V, the discharge current is 0.6 A, the temperature is 150℃, and the treatment time is 10 min; then the modification gas flow rate is adjusted to 180 sccm, the power is adjusted to 3200 W, the discharge voltage is 3500 V, the discharge current is 2.5 A, the temperature is 360℃, and the treatment time is 15 min; then the modification gas flow rate is adjusted to 80 sccm, the power is adjusted to 2500 W, the discharge voltage is 2200 V, the discharge current is 0.2 A, the temperature is 220℃, and the treatment time is 20 min;

[0099] The plasma power is turned off, the modification gas is replaced with N2, the exhaust valve is closed, the discharge valve is opened, and the silicon-carbon powder is delivered to the discharge bin to obtain the finished product.

[0100] Comparative Example 1

[0101] The porous carbon powder (D50 of 2 μm, porosity of 80%) is sucked into the feeding bin by negative pressure, the feeding valve is opened, and the porous carbon powder is delivered to the fluidized reactor by automatic feeding;

[0102] The vacuum pump and the exhaust valve are opened, inert gas N2 is introduced, the gas flow rate is adjusted to 100 sccm, the plasma power is adjusted to 1000 W, the discharge voltage is 2500 V, the discharge current is 2 A, the temperature is 250℃, and the treatment time is 15 min;

[0103] The modification gas is introduced, the modification gas includes N2, silane and methane (volume ratio 1:1:1), the modification gas flow rate is adjusted to 100 sccm, the plasma power is adjusted to 2000 W, the discharge voltage is 2500 V, the discharge current is 1 A, the temperature is 300℃, and the treatment time is 45 min;

[0104] The plasma power is turned off, the modification gas is replaced with N2, the exhaust valve is closed, the discharge valve is opened, and the silicon-carbon powder is delivered to the discharge bin to obtain the finished product.

[0105] Comparative Example 2

[0106] The porous carbon powder (D50 of 2 μm, porosity of 80%) was sucked into the feeding bin by negative pressure, the feeding valve was opened, and the porous carbon powder was transported into the fluidized reactor by automatic feeding;

[0107] The vacuum pump and the exhaust valve were opened, inert gas N2 was introduced, the gas flow rate was adjusted to 100 sccm, the plasma power was turned on, the power was adjusted to 1000 W, the discharge voltage was 2500 V, the discharge current was 2 A, the temperature was 250°C, and the treatment time was 15 min;

[0108] The modification gas was introduced, the modification gas included N2, silane and methane (volume ratio 1:1:1); the modification gas flow rate was adjusted to 200 sccm, the plasma power was turned on, the power was adjusted to 4000 W, the discharge voltage was 5000 V, the discharge current was 3 A, the temperature was 400°C, and the treatment time was 30 min;

[0109] The modification gas flow rate was adjusted to 60 sccm, the power was adjusted to 600 W, the discharge voltage was 1500 V, the discharge current was 1.0 A, the temperature was 200°C, and the treatment time was 15 min;

[0110] The plasma power was turned off, the modification gas was replaced with N2, the exhaust valve was closed, the discharge valve was opened, and the silicon-carbon powder was transported into the discharge bin to obtain the finished product.

[0111] Comparative Example 3

[0112] The porous carbon powder (D50 of 2 μm, porosity of 80%) was sucked into the feeding bin by negative pressure, the feeding valve was opened, and the porous carbon powder was transported into the fluidized reactor by automatic feeding;

[0113] The vacuum pump and the exhaust valve were opened, inert gas N2 was introduced, the gas flow rate was adjusted to 100 sccm, the plasma power was turned on, the power was adjusted to 1000 W, the discharge voltage was 2500 V, the discharge current was 2 A, the temperature was 250°C, and the treatment time was 15 min;

[0114] The modification gas was introduced, the modification gas included N2, silane and methane (volume ratio 1:1:1); the modification gas flow rate was adjusted to 200 sccm, the plasma power was turned on, the power was adjusted to 4000 W, the discharge voltage was 5000 V, the discharge current was 3 A, the temperature was 400°C, and the treatment time was 45 min;

[0115] The plasma power was turned off, the modification gas was replaced with N2, the exhaust valve was closed, the discharge valve was opened, and the silicon-carbon powder was transported into the discharge bin to obtain the finished product.

[0116] The silicon-carbon powder of Examples 1 to 6 and the silicon-carbon powder of Comparative Examples 1 to 3 are used to prepare a negative electrode of a lithium battery, and the lithium battery is prepared according to the following steps:

[0117] 1. In a vacuum environment, the silicon-carbon powder, polyvinylidene fluoride, conductive carbon black and sodium carboxymethyl cellulose are mixed in a mass ratio of 95:2:1.5:1.5, deionized water is added for homogeneous stirring and mixing to obtain a slurry, the slurry is coated on a copper foil with a thickness of 8 μm, dried at 85°C for 2 h, then dried at 100°C for 12 h, and rolled to a compacted density of 1.65 g / cm 3 After slicing, a negative electrode sheet is obtained;

[0118] 2. In a vacuum environment, the lithium manganese iron phosphate, polyvinylidene fluoride, carbon nanotubes and conductive carbon black are mixed in a mass ratio of 96:2:1:1, N-methyl pyrrolidone is added for homogeneous stirring and mixing to obtain a slurry, the slurry is coated on an aluminum foil with a thickness of 12 μm, dried at 100°C for 2 h, oven dried at 150°C for 12 h, and rolled to a compacted density of 4.1 g / cm 3 After slicing, a positive electrode sheet is obtained;

[0119] 3. The separator is a PE non-woven fabric separator with a thickness of 9 μm;

[0120] 4. Under N2 atmosphere, PC:EC:PP:PS:LiPF6:FEC = 12:12:47:4:15:10 are mixed in a mass ratio, stirred uniformly to obtain an electrolyte;

[0121] 5. The negative electrode sheet, the positive electrode sheet, the separator and the electrolyte are packaged in an aluminum plastic film, baked at 80°C for 12 h, then placed, charged to the upper limit of the battery voltage at a current of 0.2C, then discharged to 3.8V at a current of 0.1C, and the rest is a conventional means, which will not be described here.

[0122] The lithium battery prepared is subjected to electrochemical performance test, charged at 1.5C to 4.45V, charged at constant voltage to 0.05C, placed for 10 min, discharged at 1C to 3.0V, placed for 10 min, and the above charging and discharging steps are repeated to record the results as shown in Table 1:

[0123] Table 1

[0124]

[0125] Figure 3The transmission electron microscope image of the silicon-carbon powder obtained in Example 2 can be seen that the thickness of the coating layer formed on the surface of the silicon-carbon powder obtained by the dispersion adsorption process based on the silicon-carbon powder is uniform, and the silicon doping uniformity of the silicon-carbon powder obtained by the dispersion adsorption process based on the silicon-carbon powder is good, which makes the thickness growth of the lithium battery prepared by the silicon-carbon powder slow and the cycle performance of the lithium battery good.

[0126] The above examples only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as the limitation of the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A dispersion adsorption process based on silicon carbon powder, characterized in that, The method comprises the following steps: obtaining porous carbon powder; inputting inert gas to the porous carbon powder for fluidization treatment; plasma treatment of the inert gas; inputting modification gas to the porous carbon powder for fluidization treatment, wherein the modification gas at least comprises a silane compound and a hydrocarbon compound; plasma treatment of the modification gas, wherein the modification gas is inputted into the porous carbon powder, and the porous carbon powder and the plasma gas can be uniformly dispersed and mixed; wherein the plasma treatment of the modification gas comprises the following steps: primary plasma treatment of the modification gas, wherein the flow rate of the modification gas is 10-50 sccm, the plasma power is 100-500 W, the discharge voltage is 500-1500 V, the discharge current is 0.2-0.8 A, and the temperature is 50-200℃; secondary plasma treatment of the modification gas, wherein the flow rate of the modification gas is 100-200 sccm, the plasma power is 2000-4000 W, the discharge voltage is 2500-5000 V, the discharge current is 1-3 A, and the temperature is 300-400℃; tertiary plasma treatment of the modification gas, wherein the flow rate of the modification gas is 50-100 sccm, the plasma power is 500-2000 W, the discharge voltage is 1500-2500 V, the discharge current is 0.5-1.5 A, and the temperature is 100-300℃.

2. The dispersion adsorption process based on silicon-carbon powder according to claim 1, characterized in that, the hydrocarbon compound is at least one of methane, ethane and acetylene; and / or the silane compound is monosilane and / or disilane.

3. The dispersion adsorption process based on silicon-carbon powder according to claim 1, wherein, the particle size distribution of the porous carbon powder is 0.2-12 μm, and D50 is 1-4 μm; and / or The pore size distribution of the porous carbon powder is 0.2 nm to 3.5 nm, the pore volume is 0.25 cm 3 / g to 1 cm 3 / g, and the porosity is 60% to 95%; and / or, The specific surface area of the porous carbon powder is 1000 m 2 / g ~ 2500 m 2 / g; and / or, The bulk density of the porous carbon powder is 0.01 cm 3 / g ~ 0.2 cm 3 / g.

4. The dispersion adsorption process based on silicon-carbon powder according to claim 1, wherein, inputting inert gas to the porous carbon powder for fluidization treatment, wherein the flow rate of the inert gas is 5-200 sccm; and / or plasma treatment of the inert gas, wherein the plasma power is 100-1500 W, the discharge voltage is 500-5000 V, the discharge current is 0.2-3 A, and the temperature is 50-400℃.

5. The dispersion adsorption process based on silicon-carbon powder according to claim 1, wherein the modification gas further comprises inert gas.

6. The dispersion adsorption process based on silicon-carbon powder according to claim 1 or 5, wherein, the inert gas is nitrogen and / or argon.

7. An apparatus for producing silicon-carbon powder for carrying out the dispersion adsorption process based on silicon-carbon powder according to any one of claims 1 to 6, characterized by the manufacturing equipment of the porous carbon powder comprises: a powder fluidization system; a feeding system, which is in communication with the powder fluidization system, and is used for adding porous carbon powder to obtain the porous carbon powder and input the porous carbon powder into the powder fluidization system; a gas source system, which is in communication with the powder fluidization system, and is used for inputting modification gas to the porous carbon powder for fluidization treatment; a plasma discharge system, which is in communication with the powder fluidization system, and is used for plasma treatment of the modification gas. A control system, which is electrically connected to the powder fluidization system, the gas source system and the plasma discharge system respectively, to control the flow rate of the plasma gas, and the plasma power source power, discharge voltage, discharge current and temperature; An outlet system, which is in communication with the powder fluidization system, to receive the porous carbon powder output from the powder fluidization system.

8. A silicon carbon powder, characterized by, The porous carbon powder is prepared by the production equipment of claim 7.

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