Device and method for continuously preparing silicon-carbon composite negative electrode material based on multiple fluidized beds

Abstract

The invention relates to a device and a method for continuously preparing a silicon-carbon composite negative electrode material based on multiple fluidized beds. The device comprises a carbon activation fluidized bed, a passivation fluidized bed and a silicon deposition and carbon coating fluidized bed which are sequentially connected in series, a first loop gas sealer is arranged between the carbon activation fluidized bed and the passivation fluidized bed; a second loop gas sealer is arranged between the silicon deposition and carbon coating fluidized bed and the passivation fluidized bed; the two ends of the first loop gas sealer and the two ends of the second loop gas sealer are each independently provided with a double-end inert gas sealing nozzle. A top gas outlet of the silicon deposition and carbon coating fluidized bed is connected with a bottom gas inlet of the passivation fluidized bed; the carbon activation fluidized bed is independently provided with a gas inlet and a feeding hole respectively; a gas inlet and a discharge hole are formed in the bottom of the silicon deposition and carbon coating fluidized bed. The device disclosed by the invention can realize continuous production of the silicon-carbon composite negative electrode material, and the production efficiency and the process safety are greatly improved.

Description

Technical Field

[0001] This invention relates to the field of silicon-carbon anode material preparation technology, and in particular to an apparatus and method for continuous preparation of silicon-carbon composite anode materials based on multi-fluidized beds. Background Technology

[0002] With the increasing demand for high-energy-density lithium-ion batteries, traditional graphite anodes (theoretical capacity 372 mAh·g) are becoming increasingly important. -1 Silicon is no longer sufficient to meet the energy density requirements of next-generation energy storage devices. Silicon, due to its high theoretical specific capacity (approximately 4200 mAh·g), is no longer suitable. -1 Silicon is a promising next-generation anode material due to its abundant reserves and low cost. However, silicon undergoes volume expansion of up to 300% or more during charge and discharge, leading to particle pulverization, damage to the conductive network, and repeated formation of the solid electrolyte interphase (SEI) film, resulting in severely degraded cycle performance.

[0003] To alleviate the aforementioned problems, researchers have proposed preparing silicon-carbon (Si / C) composite anode materials by combining silicon and carbon. The carbon phase (graphite, amorphous carbon, activated carbon, petroleum coke, biomass carbon, etc.) can provide a conductive network and buffer silicon volume changes. Currently, the main methods for preparing silicon-carbon materials include mechanical mixing, sol-gel methods, polymerization coating methods, and chemical vapor deposition (CVD). Mechanical mixing involves mixing silicon powder and carbon powder through ball milling and ultrasonic dispersion. While simple, this method suffers from low bonding strength, uneven dispersion, and an inability to achieve nanoscale composites. It also struggles to produce large-scale, batch-uniform products with poor performance. Sol-gel and polymer coating methods use organic carbon sources as precursors, forming a carbon coating layer through pyrolysis. Although these methods offer better carbon coating uniformity, they are complex, have low yields, and are costly, making them unsuitable for large-scale production. Chemical vapor deposition (CVD) uses silicon sources such as SiH4, SiCl4, and SiH2Cl2, which are pyrolyzed at high temperatures in an inert or hydrogen atmosphere to deposit silicon in situ on the carbon material surface. Subsequent secondary carbon coating is achieved using carbon sources such as acetylene or methane. CVD effectively controls the dispersion morphology and film thickness of silicon, resulting in high-performance silicon-carbon materials, making it the most promising mainstream process currently.

[0004] CN120662212A designs a multi-stage variable-diameter fluidized bed series system, combining the continuous coupling of silane pyrolysis deposition and acetylene carbon coating processes, to achieve automated continuous production from silicon deposition to carbon coating. However, it has not yet achieved continuous production under a completely closed atmosphere. There is a lack of independent isolation structure between the oxidizing and reducing reaction environments, which poses gas cross-flow and safety risks. At the same time, the system structure is complex, the consumption of inert gas is large, the energy consumption is high, and the carbon material activation stage is not covered, so it is impossible to complete the entire continuous process from raw carbon to silicon-carbon composite materials.

[0005] CN120039880A uses a multi-step process of esterification-carbonization-KOH activation-vapor phase deposition to transform natural starch into a porous carbon framework that maintains a spherical morphology, and then uses fluidized bed CVD to prepare silicon-carbon materials. However, the process involves many steps and complex operations, and does not have the potential for continuous preparation. The activation and deposition processes are energy-intensive and time-consuming. Fluidized bed deposition only achieves single-bed reaction and does not consider atmosphere isolation and safety interlock control. In addition, the material properties mainly depend on laboratory conditions and lack industrial scale-up verification and cost assessment.

[0006] CN120393868A proposes a continuous preparation system combining a fluidized bed reactor and a vapor deposition rotary furnace. It adopts a multi-segment spouted fluidized bed structure to achieve internal circulation fluidization of particles, improve gas-solid contact efficiency, and make the process flow of "silicon deposition – carbon coating – deep carbonization" smooth, significantly improving product uniformity and production efficiency. However, the process is still a sequential stepwise reaction and does not achieve independent isolation between oxidizing and reducing atmospheres. It relies on a multi-stage heating and conveying system, which leads to complex equipment and high investment. The system has extremely high requirements for powder fluidization and combustible gas safety control, does not form an inherently safe dual-atmosphere closed system, and lacks a porous carbon activation process.

[0007] However, the current CVD method for preparing silicon-carbon materials has many limitations:

[0008] (1) The process steps are fragmented and it is difficult to achieve continuous production: The existing process usually prepares porous carbon through chemical activation, then washes, purifies and dries it, and then deposits silicon to coat carbon in another reactor. The steps are cumbersome and the process is lengthy, making it impossible to achieve large-scale continuous production.

[0009] (2) High energy consumption and poor scalability: Traditional CVD reactors are mostly single-bed intermittent operation, with low output per unit time and significant energy consumption during system heating and cooling processes; when scaled up to the kilogram level, gas stagnation and temperature gradients are likely to occur, making it difficult to maintain product consistency.

[0010] (3) Incompatible reaction atmospheres pose significant safety hazards: The carbon activation process using a fluidized bed requires oxidizing gases such as CO2 or H2O, while SiH4 and C2H2 deposition require an oxygen-free flammable atmosphere. These two atmospheres are difficult to reconcile within the same system, and incomplete switching can lead to the risk of deflagration.

[0011] (4) Unstable fluidization state and poor deposition uniformity: Class C particles in activated fluidized bed are difficult to fluidize stably under simple flow field, making it difficult to obtain porous carbon with uniform surface and pore structure. In subsequent fluidized bed CVD process, the powder is prone to agglomeration and wall adhesion, resulting in uneven deposition distribution and uneven coating, which leads to local stress concentration and product instability in the obtained silicon-carbon material.

[0012] To overcome the above problems, this invention proposes a method for the continuous preparation of silicon-carbon composite anode materials based on multi-fluidized beds. By connecting a carbon material activation bed and a silane deposition bed in series and setting up a loop sealer with double-ended N2 gas seal to achieve atmosphere isolation, continuous particle transport is achieved while ensuring that the atmospheres do not interfere with each other. The method achieves partitioned synergy and continuous preparation of porous carbon activation and silicon / carbon deposition processes, overcoming the problems of process fragmentation, high energy consumption and pollution, poor batch consistency, poor industrial scalability, and poor safety in the prior art. Summary of the Invention

[0013] To address the aforementioned technical problems, this invention provides an apparatus and method for the continuous preparation of silicon-carbon composite anode materials based on a multi-fluidized bed. This invention connects a carbon material activation bed and a silane deposition bed in series, and uses a loop sealer with double-ended N2 gas to achieve atmosphere isolation. While ensuring that the atmospheres do not interfere with each other, continuous particle transport is achieved. This allows for the zoned synergy and continuous preparation of porous carbon activation and silicon / carbon deposition processes, overcoming the problems of process fragmentation, high energy consumption and pollution, poor batch consistency, poor industrial scalability, and poor safety in existing technologies.

[0014] To achieve this objective, the present invention adopts the following technical solution:

[0015] In a first aspect, the present invention provides an apparatus for the continuous preparation of silicon-carbon composite anode materials based on multiple fluidized beds, the apparatus comprising a carbon-activated fluidized bed, a passivation fluidized bed, and a silicon deposition and carbon coating fluidized bed connected in series.

[0016] A first loop gas seal is provided between the carbon-activated fluidized bed and the passivation fluidized bed; a second loop gas seal is provided between the silicon deposition and carbon-coated fluidized bed and the passivation fluidized bed; each of the first loop gas seal and the second loop gas seal is independently provided with a double-ended inert gas seal nozzle at both ends;

[0017] The top air outlet of the silicon deposition and carbon coating fluidized bed is connected to the bottom air inlet of the passivation fluidized bed; the carbon activation fluidized bed is independently provided with an air inlet and a feed inlet; the bottom of the silicon deposition and carbon coating fluidized bed is provided with an air inlet and a feed outlet.

[0018] The device of this invention employs a dual-bed series structure design. The front bed (carbon-activated fluidized bed) enables online physical activation of carbon materials, while the rear bed (silicon deposition and carbon coating fluidized bed) enables SiH4 deposition and C2H2 coating. The two are continuously transferred through a loop gas sealer, achieving continuous solid flow and continuous process operation, significantly improving production efficiency. The loop gas sealer in this invention, by setting double-ended inert gas seal nozzles, only allows material-to-material transfer. The gas curtain forms a gas isolation layer at both ends, preventing oxidizing gases (CO2 / H2O) and combustible gases (SiH4, C2H2) from flowing into each other, achieving unidirectional solid transport and bidirectional gas blocking, thereby ensuring system operation safety. The device of this invention is suitable for the large-scale production of silicon-carbon anode materials for lithium-ion batteries.

[0019] As a preferred embodiment of the present invention, an annular gas distributor is provided at the bottom of the carbon-activated fluidized bed.

[0020] Preferably, the carbon-activated fluidized bed is further equipped with a temperature control heating system, a pressure detection system, a safety valve, and a gas flow control system.

[0021] Preferably, the upper part of the carbon-activated fluidized bed is provided with an air hammer, a backflush air inlet, and a filter tube.

[0022] Preferably, an air hammer is provided at the upper part of the passivation fluidized bed; and an annular gas distributor is provided at the bottom of the passivation fluidized bed.

[0023] In this invention, by setting an air hammer and a backflush air inlet on the carbon-activated fluidized bed, particulate materials can be prevented from adhering to the top wall of the device.

[0024] As a preferred technical solution of the present invention, the bottom of the silicon deposition and carbon coating fluidized bed is provided with a stirring drive device and a gas distributor.

[0025] Preferably, the top outlet of the silicon deposition and carbon coating fluidized bed is also connected to an exhaust gas treatment device.

[0026] Preferably, the silicon deposition and carbon coating fluidized bed is further equipped with a temperature control heating system, a pressure detection system, a safety valve, and a gas flow control system.

[0027] Preferably, the upper part of the silicon deposition and carbon coating fluidized bed is provided with a filter tube, an air hammer, and a backflush air inlet.

[0028] As a preferred embodiment of the present invention, the apparatus further includes a gas storage device and a raw material storage device.

[0029] Preferably, the gas storage device includes an activation gas storage device, a silicon source gas storage device, and a carbon source gas storage device.

[0030] Preferably, the activation gas storage device and the raw material storage device are each independently connected to the air inlet and feed inlet of the carbon-activated fluidized bed through a gas flow control system; the silicon source gas storage device and the carbon source gas storage device are each independently connected to the air inlet of the silicon deposition and carbon coating fluidized bed through a gas flow control system.

[0031] As a preferred embodiment of the present invention, the device includes a PCL or DCS control system; each of the PCL or DCS control systems is independently connected to the temperature control heating system, the pressure detection system, the safety valve, and the gas flow control system.

[0032] As a preferred embodiment of the present invention, a heating device is further provided on the connecting pipeline between the activation gas storage device and the inlet of the carbon activation fluidized bed.

[0033] Preferably, the activated gas storage device is also connected to a driving device.

[0034] In a second aspect, the present invention provides a method for the continuous preparation of silicon-carbon composite anode materials based on multi-fluidized beds, the method being carried out using the apparatus described in the first aspect.

[0035] As a preferred embodiment of the present invention, the method includes: activating gas and raw materials entering the device through the inlet and feed inlet of the carbon-activated fluidized bed, respectively, to perform a carbon activation reaction and generate porous carbon; the porous carbon entering the passivation fluidized bed through a first loop gas sealer; the tail gas generated during the silicon deposition process flowing from the top outlet of the silicon deposition and carbon coating fluidized bed into the bottom inlet of the passivation fluidized bed, and serving as fluidizing gas to perform a passivation reaction, exchanging heat with the porous carbon to reduce the temperature to that required for silicon deposition; subsequently, the product entering the silicon deposition and carbon coating fluidized bed through a second loop gas sealer, and the silicon source gas entering the device through the inlet of the silicon deposition and carbon coating fluidized bed to perform a silicon deposition reaction; subsequently, the carbon source gas is switched to perform a carbon coating reaction to obtain a silicon-carbon composite anode material, and the tail gas entering the passivation fluidized bed as fluidizing gas.

[0036] The method of the present invention involves a carbon activation reaction in a carbon-activated fluidized bed to generate a porous carbon framework with well-developed micropores and mesopores; a passivation reaction is then carried out in a passivation fluidized bed to complete the gas replacement and passivation of the porous carbon surface, effectively suppressing the silane deposition side reaction; finally, a silicon chemical vapor deposition reaction and a carbon coating reaction are carried out in a silicon deposition and carbon coating fluidized bed to form a stable outer carbon shell, thereby obtaining the silicon-carbon composite anode material.

[0037] As a preferred embodiment of the present invention, the activating gas includes CO2 and / or H2O.

[0038] Preferably, the raw material includes any one or a combination of at least two of resin-based charcoal, biochar, pitch charcoal, coal-based charcoal, and petroleum coke. Typical but non-limiting examples of such combinations include: resin-based charcoal and biocharcoal, biocharcoal and pitch charcoal, pitch charcoal and coal-based charcoal, coal-based charcoal and petroleum coke, etc.

[0039] Preferably, the silicon source gas includes N2 and SiH4.

[0040] Preferably, the carbon source gas includes acetylene.

[0041] As a preferred technical solution of the present invention, the temperature of the carbon activation reaction is 800-900℃, such as 800℃, 820℃, 840℃, 860℃, 880℃, 900℃, etc., but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0042] Preferably, the temperature of the silicon deposition reaction is 500-600℃, such as 500℃, 520℃, 540℃, 560℃, 580℃, 600℃, etc., but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0043] Preferably, the temperature of the carbon coating reaction is 500-600℃, such as 500℃, 520℃, 540℃, 560℃, 580℃, 600℃, etc., but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0044] Preferably, the porous carbon is passivated and heat-exchanged in a passivated fluidized bed, and small porous carbon particles with a particle size of <2μm are removed by sieving.

[0045] Preferably, the porous carbon is screened in a passivated fluidized bed to remove small porous carbon particles with a particle size <1μm.

[0046] Preferably, the heat exchange with the porous carbon is reduced to the temperature required for silicon deposition in the range of 500-600°C, such as 500°C, 520°C, 540°C, 560°C, 580°C, 600°C, etc., but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0047] Preferably, the exhaust gas is the exhaust gas from the silicon deposition process, with a portion entering the exhaust gas treatment device and a portion entering the passivation fluidized bed.

[0048] Preferably, the exhaust gas is a mixture of H2 and N2 or pure H2 gas.

[0049] In this invention, the exhaust gas generated during silicon deposition is introduced into the passivation fluidized bed. On the one hand, the gas is purified to remove oxidizing gases; on the other hand, the sieving effect is used to screen qualified products and remove fine carbon powder with a particle size of <1μm, thereby removing fine powder and passivating the surface, significantly reducing the specific surface area of ​​the subsequent silicon-carbon composite material; at the same time, it can also play a cooling role, reaching the temperature required for delivery to the silicon deposition and carbon coating fluidized bed.

[0050] Compared with the prior art, the present invention has at least the following beneficial effects:

[0051] (1) The device of the present invention adopts a dual-bed series structure design. The front bed (carbon activation fluidized bed) realizes the online physical activation of carbon materials, and the rear bed (silicon deposition and carbon coating fluidized bed) realizes SiH4 deposition and C2H2 coating. The two are continuously transferred through a loop gas sealer to realize continuous solid flow and continuous process operation, which greatly improves production efficiency.

[0052] (2) Since the two beds are in different reaction atmospheres (CO2 / water vapor and H2 / SiH4 / C2H2), by setting up a loop gas sealer, the double-ended inert gas seal nozzles are used to allow only the transfer between materials. The gas curtain forms a gas isolation layer at the upper and lower ends to prevent oxidizing gas (CO2 / H2O) and combustible gas (SiH4, C2H2) from flowing into each other, realizing unidirectional solid transport and bidirectional gas blocking, thereby ensuring the safe operation of the system; the device of the present invention is suitable for the large-scale production of silicon-carbon anode materials for lithium-ion batteries;

[0053] (3) The fluidized bed structure of the present invention combines fluidized reaction with mechanical stirring and multi-point gas distribution design to make the powder particles uniformly distributed and fully contacted with the reaction gas in the two beds. By changing the activation fluidized bed atmosphere, temperature, time, etc., porous carbon with different specific surface areas and pore structures can be obtained. By changing the deposition and coating fluidized bed atmosphere, temperature, time, etc., silicon-carbon materials with different deposition amounts and coating amounts can be obtained. The final silicon-carbon composite material has uniform silicon distribution, controllable pore structure and high specific capacity stability.

[0054] (4) The device of the present invention can operate continuously, reducing the need for multiple heating, cooling, vacuuming and gas replacement steps; the introduction of gas circulation and waste heat recovery units effectively reduces energy consumption; the closed system such as air hammer and backflushing prevents dust and SiH4 from escaping, which meets the requirements of green manufacturing; the dual-bed design can be modularly scaled up to adapt to different production needs; the system can be integrated with automatic feeding, dust removal and tail gas purification units, and is suitable for large-scale production of silicon-carbon anode materials for lithium-ion batteries. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of a device for the continuous preparation of silicon-carbon composite anode materials based on multi-fluidized beds, provided by the present invention.

[0056] Among them, 1-carbon activated fluidized bed, 1.1-air inlet, 1.2-feed inlet, 1.3-air hammer, 1.4-backflush air inlet, 1.5-filter tube, 2-passivating fluidized bed, 2.1-bottom air inlet, 2.2-air hammer, 3-silicon deposition and carbon coating fluidized bed, 3.1-top air outlet, 3.2-air inlet, 3.3 stirring drive device, 3.4-discharge outlet, 3.5-filter tube, 3.6-air hammer, 3.7-backflush air inlet, 4-first loop sealer, 5-second loop sealer, 6-tail gas treatment device, 7-activation gas storage device, 8-raw material storage device, 9-heating device, 10-drive device. Detailed Implementation

[0057] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0058] Example 1

[0059] This embodiment provides an apparatus for the continuous preparation of silicon-carbon composite anode materials based on multiple fluidized beds. The apparatus includes a carbon-activated fluidized bed 1, a passivation fluidized bed 2, and a silicon deposition and carbon coating fluidized bed 3 connected in series.

[0060] A first loop sealer 4 is provided between the carbon-activated fluidized bed 1 and the passivation fluidized bed 2; a second loop sealer 5 is provided between the silicon deposition and carbon coating fluidized bed 3 and the passivation fluidized bed 2; and each of the first loop sealer 4 and the second loop sealer 5 is independently provided with a double-ended inert gas seal nozzle.

[0061] The top air outlet 3.1 of the silicon deposition and carbon coating fluidized bed 3 is connected to the bottom air inlet 2.1 of the passivation fluidized bed 2; the carbon activation fluidized bed 1 is independently provided with an air inlet 1.1 and a feed inlet 1.2; the bottom of the silicon deposition and carbon coating fluidized bed 3 is provided with an air inlet 3.2 and a feed outlet 3.4;

[0062] The bottom of the carbon-activated fluidized bed 1 is provided with an annular gas distributor; the carbon-activated fluidized bed 1 is also provided with a temperature control heating system, a pressure detection system, a safety valve and a gas flow control system; the upper part of the carbon-activated fluidized bed 1 is provided with an air hammer 1.3, a backflush air inlet 1.4 and a filter tube 1.5; the upper part of the passivation fluidized bed 2 is provided with an air hammer 2.2; the bottom of the passivation fluidized bed is provided with an annular gas distributor.

[0063] The bottom of the silicon deposition and carbon coating fluidized bed 3 is equipped with a stirring drive device 3.3 and a gas distributor; the top gas outlet 3.1 of the silicon deposition and carbon coating fluidized bed 3 is also connected to the tail gas treatment device 6; the silicon deposition and carbon coating fluidized bed 3 is also equipped with a temperature control heating system, a pressure detection system, a safety valve and a gas flow control system; the upper part of the silicon deposition and carbon coating fluidized bed 3 is equipped with a filter tube 3.5, an air hammer 3.6 and a backflush air inlet 3.7;

[0064] The apparatus further includes a gas storage device and a raw material storage device 8; the gas storage device includes an activation gas storage device 7, a silicon source gas storage device, and a carbon source gas storage device; the activation gas storage device 7 and the raw material storage device 8 are each independently connected to the air inlet 1.1 and the feed inlet 1.2 of the carbon activation fluidized bed 1 through a gas flow control system; the silicon source gas storage device and the carbon source gas storage device are each independently connected to the air inlet 3.2 of the silicon deposition and carbon coating fluidized bed 3 through a gas flow control system;

[0065] The device includes a PCL control system; each PCL control system is independently connected to a temperature control heating system, a pressure detection system, a safety valve, and a gas flow control system.

[0066] A heating device 9 is also provided on the connecting pipeline between the activation gas storage device 7 and the carbon activation fluidized bed inlet 1.1; the activation gas storage device 7 is also connected to the driving device 10.

[0067] Application Example 1

[0068] This application example provides a method for the continuous preparation of silicon-carbon composite anode materials based on a multi-fluidized bed, using the apparatus described in Example 1. The method includes: activation gas and raw materials entering the apparatus through the inlet 1.1 and feed inlet 1.2 of the carbon-activated fluidized bed 1, respectively, to undergo a carbon activation reaction, generating porous carbon; the porous carbon entering the passivation fluidized bed 2 through a first loop sealer 4; and tail gas generated during silicon deposition flowing into the apparatus through the top outlet 3.1 of the silicon deposition and carbon-coated fluidized bed 3. The passivation fluidized bed 2 has a bottom inlet 2.1, which serves as the fluidizing gas for the passivation reaction. The gas exchanges heat with the porous carbon to lower the temperature to the level required for silicon deposition. The product then enters the silicon deposition and carbon coating fluidized bed 3 through the second loop sealer 5. The silicon source gas enters the device through the inlet 3.2 of the silicon deposition and carbon coating fluidized bed 3 for the silicon deposition reaction. Subsequently, the carbon source gas is switched to perform a carbon coating reaction, yielding a silicon-carbon composite anode material. The byproduct enters the passivation fluidized bed 2 as the fluidizing gas.

[0069] The activation gas includes CO2 and / or H2O; the raw materials include resin-based carbon and biochar; the silicon source gas includes N2 and SiH4; the carbon source gas includes acetylene; the carbon activation reaction temperature is 800℃; the silicon deposition reaction temperature is 500℃; the carbon coating reaction temperature is 500℃; the porous carbon undergoes passivation and heat exchange in a passivation fluidized bed, and small porous carbon particles with a particle size <2μm are sieved out; the temperature is reduced to 500℃, which is the temperature required for silicon deposition, through heat exchange with the porous carbon; the exhaust gas is the exhaust gas from the silicon deposition process, part of which enters the exhaust gas treatment device 6, and part of which enters the passivation fluidized bed 2; the exhaust gas is a mixture of H2 and N2.

[0070] In summary, this invention provides an apparatus and method for the continuous preparation of silicon-carbon composite anode materials based on multi-fluidized beds. The apparatus employs a dual-bed series structure design: the front bed (carbon-activated fluidized bed) enables online physical activation of the carbon material, while the rear bed (silicon deposition and carbon coating fluidized bed) achieves SiH4 deposition and C2H2 coating. The two beds are continuously transferred via a loop gas sealer, achieving continuous solid flow and continuous process operation, significantly improving production efficiency. Since the two beds are in different reaction atmospheres (CO2 / water vapor and H2 / SiH4 / C2H2), the loop gas sealer, with its double-ended inert gas-sealed nozzles, allows only material transfer. A gas curtain forms a gas isolation layer at both ends, preventing cross-flow of oxidizing gases (CO2 / H2O) and combustible gases (SiH4, C2H2), achieving unidirectional solid transport and bidirectional gas blocking, thus ensuring system safety. The apparatus of this invention is suitable for the large-scale production of silicon-carbon anode materials for lithium-ion batteries.

[0071] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. An apparatus for continuous preparation of silicon-carbon composite anode materials based on multi-fluidized beds, characterized in that, The device includes a carbon-activated fluidized bed, a passivation fluidized bed, and a silicon deposition and carbon-coated fluidized bed connected in series. A first loop gas seal is provided between the carbon-activated fluidized bed and the passivation fluidized bed; a second loop gas seal is provided between the silicon deposition and carbon-coated fluidized bed and the passivation fluidized bed; each of the first loop gas seal and the second loop gas seal is independently provided with a double-ended inert gas seal nozzle at both ends; The top air outlet of the silicon deposition and carbon coating fluidized bed is connected to the bottom air inlet of the passivation fluidized bed; the carbon activation fluidized bed is independently provided with an air inlet and a feed inlet; the bottom of the silicon deposition and carbon coating fluidized bed is provided with an air inlet and a feed outlet.

2. The apparatus according to claim 1, characterized in that, An annular gas distributor is provided at the bottom of the carbon-activated fluidized bed; Preferably, the carbon-activated fluidized bed is further equipped with a temperature control heating system, a pressure detection system, a safety valve, and a gas flow control system; Preferably, the upper part of the carbon-activated fluidized bed is provided with an air hammer, a backflush air inlet, and a filter tube; Preferably, an air hammer is provided at the upper part of the passivation fluidized bed; and an annular gas distributor is provided at the bottom of the passivation fluidized bed.

3. The apparatus according to claim 1 or 2, characterized in that, The bottom of the silicon deposition and carbon coating fluidized bed is equipped with a stirring drive device and a gas distributor. Preferably, the top outlet of the silicon deposition and carbon coating fluidized bed is also connected to a tail gas treatment device; Preferably, the silicon deposition and carbon coating fluidized bed is further equipped with a temperature control heating system, a pressure detection system, a safety valve, and a gas flow control system; Preferably, the upper part of the silicon deposition and carbon coating fluidized bed is provided with a filter tube, an air hammer, and a backflush air inlet.

4. The apparatus according to any one of claims 1-3, characterized in that, The device also includes a gas storage device and a raw material storage device; Preferably, the gas storage device includes an activation gas storage device, a silicon source gas storage device, and a carbon source gas storage device; Preferably, the activation gas storage device and the raw material storage device are each independently connected to the air inlet and feed inlet of the carbon-activated fluidized bed through a gas flow control system; the silicon source gas storage device and the carbon source gas storage device are each independently connected to the air inlet of the silicon deposition and carbon coating fluidized bed through a gas flow control system.

5. The apparatus according to any one of claims 1-4, characterized in that, The device includes a PCL or DCS control system; each of the PCL or DCS control systems is independently connected to the temperature control heating system, pressure detection system, safety valve, and gas flow control system.

6. The apparatus according to any one of claims 1-5, characterized in that, A heating device is also provided on the connecting pipeline between the activation gas storage device and the inlet of the carbon activation fluidized bed; Preferably, the activated gas storage device is also connected to a driving device.

7. A method for continuous preparation of silicon-carbon composite anode materials based on multi-fluidized bed, characterized in that, The method is performed using the apparatus as described in any one of claims 1-6.

8. The method according to claim 7, characterized in that, The method includes: activating gas and raw materials enter the device through the inlet and feed inlet of the carbon-activated fluidized bed, respectively, to carry out a carbon activation reaction and generate porous carbon; the porous carbon enters the passivation fluidized bed through a first loop gas sealer; the tail gas generated during silicon deposition flows from the top outlet of the silicon deposition and carbon coating fluidized bed into the bottom inlet of the passivation fluidized bed, and serves as fluidizing gas to carry out a passivation reaction, exchanging heat with the porous carbon to reduce the temperature to the level required for silicon deposition; subsequently, the product enters the silicon deposition and carbon coating fluidized bed through a second loop gas sealer, and the silicon source gas enters the device through the inlet of the silicon deposition and carbon coating fluidized bed to carry out a silicon deposition reaction; subsequently, the carbon source gas is switched to carry out a carbon coating reaction to obtain a silicon-carbon composite anode material, and the tail gas enters the passivation fluidized bed as fluidizing gas.

9. The method according to claim 7 or 8, characterized in that, The activating gas includes CO2 and / or H2O; Preferably, the raw material includes any one or a combination of at least two of resin-based charcoal, biochar, pitch charcoal, coal-based charcoal, and petroleum coke. Preferably, the silicon source gas includes N2 and SiH4; Preferably, the carbon source gas includes acetylene.

10. The method according to claim 9, characterized in that, The temperature for the carbon activation reaction is 800-900℃; Preferably, the temperature of the silicon deposition reaction is 500-600°C; Preferably, the temperature of the carbon coating reaction is 500-600℃; Preferably, the porous carbon is passivated and heat-exchanged in a passivated fluidized bed, and small porous carbon particles with a particle size <2μm are removed by sieving. Preferably, the porous carbon is screened in a passivated fluidized bed to remove small porous carbon particles with a particle size <1μm; Preferably, the heat exchange with the porous carbon is reduced to the temperature required for silicon deposition at 500-600°C. Preferably, the exhaust gas is the exhaust gas from the silicon deposition process, with a portion entering the exhaust gas treatment device and a portion entering the passivation fluidized bed. Preferably, the exhaust gas is a mixture of H2 and N2 or pure H2 gas.

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