Method and device for continuously depositing atomic layer and molecular layer

Abstract

The invention provides a method and a device for continuously depositing an atomic layer and a molecular layer, the device can perform different deposition reactions at different stations through a reactor structure and a telescopic mechanism, and the atomic layer deposition technology is sequentially performed to coat a conductive ceramic layer; and then the process of coating the carbon material through molecular deposition and high-temperature carbonization is carried out, and intermediate products do not need to be taken out midway, so that continuous operation is realized, intermediate equipment and space occupied by the equipment are reduced, and energy consumption of an intermediate process is also reduced.

Description

Technical Field

[0001] The present invention relates to the field of lithium ion battery materials and nano-preparation technology, and in particular to a method and device for continuous atomic layer and molecular layer deposition, in particular to a silicon-carbon negative electrode coating method using molecular layer deposition. Background Art

[0002] The application of silicon-based materials in lithium-ion battery negative electrodes has extremely high specific capacity, and its theoretical capacity can reach 4200mAh g -1 , so silicon-based materials have received increasing attention as negative electrode materials for lithium-ion batteries. However, the electrode cycle life is limited by cracking and pulverization caused by its large volume change (up to 311%) during charge and discharge.

[0003] At present, the carbon coating of silicon oxide particles mainly includes: liquid phase coating method and gas phase coating method, and atomic layer deposition + molecular layer deposition method disclosed in CN118016835A.

[0004] The liquid phase coating method has the problem of difficulty in fully dispersing the particles; the surface valence bond polarity of silicon oxide particles is large, and the compatibility with certain liquid phase coating agents is poor, resulting in uneven coating layer. The liquid phase coating method usually requires a long reaction time and complex operating conditions, which may also affect the uniformity of the coating layer, making it difficult to achieve mass production scale. The chemical vapor deposition (CVD) method can prepare composite particles more conveniently. That is, the raw materials are placed in a rotary furnace, rotary furnace and other equipment, set to 700-1050°C, and carbon-containing gas or steam is directly introduced to form a continuous carbon layer on the surface of the silicon oxide particles through pyrolysis, polycondensation and other reactions in the same reaction chamber. However, the CVD method causes carbon and silicon to react at high temperature to form silicon carbide, increasing resistance. Lowering the reaction temperature leads to a low degree of carbonization of the carbon coating layer, and the resistance of the coating layer cannot be reduced to the expected target.

[0005] Therefore, CN118016835A discloses that an atomic layer deposition technology is used to coat a conductive ceramic layer on the surface of silicon particles, and then a molecular deposition coating carbon material is performed. The TiN coating layer isolates the metal organic coating layer and the silicon-based negative electrode material, so that the conductive carbon layer can be carbonized at a higher temperature, making the structure denser and reducing the resistivity.

[0006] At present, the method disclosed in CN118016835A requires the use of atomic layer deposition equipment for conductive ceramic layer coating, then the use of CVD equipment for organic coating, and then the use of a rotary kiln for carbonization of organic matter. More equipment is required, the cost is high, and the particles need to be heated to a suitable temperature in each device for coating, and then cooled to room temperature to take out the product, resulting in additional energy consumption. Summary of the invention

[0007] In order to solve the above problems, the present invention proposes and adopts the following technical solution.

[0008] A device for continuous atomic layer and molecular layer deposition, comprising a heating sleeve and a reactor arranged on a bottom plate, wherein bearing supports are arranged at the left and right ends of the heating sleeve, and the reactor comprises a rotating drum and left and right reducing tubes, wherein the rotating drum sleeve is arranged inside the heating sleeve, and when the rotating drum sleeve is sleeved, the two sleeves are clearance-matched, and the left and right ends of the rotating drum are connected to the left and right reducing tubes, and the left and right reducing tubes extend from the rotating drum and are rotatably connected to the bearing supports;

[0009] One end of the left-side reduced diameter tube extending out of the heating jacket is connected to the air intake hood. A flow equalizing plate is provided on the side of the air intake hood away from the rotary drum. The flow equalizing plate divides the air intake hood into a fluidizing chamber close to the rotary drum and an air intake chamber away from the rotary drum. Atomic layer deposition precursor gas and inert gas are introduced into the air intake chamber.

[0010] The end of the rotary drum close to the air intake hood is constructed as a tapered cavity that gradually expands from the reduced diameter pipe to the rotary drum. The cross-sectional areas of the middle section of the rotary drum are equal at different distances from the air intake hood. The left reduced diameter pipe is a cylindrical body with equal diameter along the axial direction.

[0011] One end of the right-side reducing tube extending out of the heating sleeve is connected to the rotating sleeve, a sleeve is arranged inside the right reducing tube, one end of the sleeve extends out of the right reducing tube and is rotatably connected to the rotating sleeve, and the other end of the sleeve extends into the rotary cylinder, an exhaust pipe and an air inlet pipe are arranged inside the sleeve, and molecular layer deposition precursor gas and inert gas are introduced into the air inlet pipe;

[0012] The bottom plate is equipped with a driving device for driving the rotating drum to rotate; the side of the bottom plate close to the air inlet hood is connected to the base through a hinge, and the bottom plate is also connected to a telescopic mechanism, and the telescopic mechanism can be used to drive the bottom plate to rotate relative to the hinge. When the central axis of the rotating drum is perpendicular to the horizontal plane, the rotating drum is in a position for the atomic layer deposition process, and when the central axis of the rotating drum is parallel to the horizontal plane, the rotating drum is in a position for the molecular deposition and carbonization process.

[0013] A stirring paddle is installed in the fluidizing chamber, and a motor is installed at one end of the air inlet hood facing away from the rotating drum. The output shaft of the motor passes through the flow equalizing plate and the air inlet chamber to drive the stirring paddle to rotate; the air inlet chamber is connected to the air inlet joint, and the air inlet joint is detachably connected to the reaction gas pipeline, and the reaction gas pipeline is used to input atomic layer deposition precursor gas and inert gas.

[0014] The inner wall of the rotating drum is evenly provided with lifting plates along the circumferential direction. The lifting plates are parallel to the axis of the rotating drum so as not to hinder the atomic layer deposition precursor gas from fluidizing the reaction raw materials in the rotating drum. The height of the lifting plates is lower than the distance between the outlet of the air inlet pipe and the inner wall of the rotating drum.

[0015] One end of the exhaust pipe located inside the rotating drum 3 is provided with a filter, and the other end of the exhaust pipe located outside the rotating drum is connected to the differential electrochemical mass spectrometer and the vacuum pump in sequence; the end of the inlet pipe located inside the rotating drum is bent toward the bottom plate side, and the other end located outside the rotating drum is connected in parallel with different precursor gas supply pipelines, which are used to input molecular layer deposition precursor gas and inert gas.

[0016] One end of the telescopic mechanism is connected to the lower part of the base, and the other end is connected to the part of the bottom plate close to the rotating sleeve. The side of the bottom plate close to the air intake cover is connected to the upper part of the base through a hinge. The telescopic mechanism is used to drive the bottom plate (8) to rotate relative to the hinge.

[0017] When the rotary drum is in the station for the atomic layer deposition process, the fluidizing chamber of the left reducing tube is filled with particles Q to be coated, and the rotary drum is used to allow particles B that have reached the expected size after coating to settle back into the fluidizing chamber, wherein:

[0018] The diameter D3 of the rotary drum shall not be less than Fv is the design volume flow rate of fluidizing gas at the operating temperature and pressure of the device, d B and ρ B are the expected diameter of particle B and the density of particle B when it reaches the expected diameter, ρ and μ are the density and viscosity of the fluidizing gas containing the reaction precursor output from the reaction gas pipeline at the operating temperature and pressure of the device, respectively. The diameter D4 of the fluidizing chamber is smaller than D', and the density of particle Q is ρ Q , the diameter of particle Q before coating is d Q , ε=0.33~0.5, the sum of the axial height h1 of the fluidizing chamber and the left reducing tube and the axial height h2 of the conical chamber is set to be not less than h1 is set to be less than The sum of the volumes of the fluidizing chamber and the conical chamber is designed to be 1 / ε times the bulk volume of the particles Q loaded in the fluidizing chamber, A = 0.25 × π × (D4) 2 , m is the mass of particles Q loaded in the fluidizing chamber.

[0019] A method for continuously performing atomic layer and molecular layer deposition, based on the device for continuously performing atomic layer and molecular layer deposition, comprises the following steps:

[0020] S1. When the rotary drum is in the atomic layer deposition process station, the particles Q with a mass of m are loaded into the fluidizing chamber of the disassembled inlet hood, and then the inlet hood is installed back on the left reducing tube, the rotary drum is evacuated and the inert gas is replaced at least three times, the pressure of the fluidizing chamber is controlled to reach the ALD operating pressure, and then the temperature of the heating jacket is controlled to make the rotary drum reach the ALD operating temperature. The ALD operation process is repeated multiple times, and the inert gas containing the atomic layer deposition precursor gas with a volume flow rate of Fv is input into the fluidizing chamber through the reaction gas pipeline, so that the particles Q are coated with the coating layer to form a desired diameter d B Particle B settles back into the fluidization chamber;

[0021] In step S1, on the one hand, the gaps between particles B in the fluidized chamber are small, and particles B agglomerate with each other, so it is not easy to react with the atomic layer deposition precursor gas to form a coating layer, and the size continues to increase. On the other hand, the temperature in the fluidized chamber is lower than the ALD operating temperature, and the atomic layer deposition precursor gas is difficult to react with the particle surface, thereby increasing the particle size.

[0022] S2. After the atomic layer deposition is completed, the telescopic mechanism is operated to make the central axis of the rotary drum parallel to the horizontal plane, the rotary drum is in the position for the molecular deposition and carbonization process, the inert gas is input into the fluidization chamber through the reaction gas pipeline, the particles B are blown into the rotary drum, and then the connection between the reaction gas pipeline and the air inlet joint is disconnected, and the air inlet joint is blocked;

[0023] S3. According to the type of particles B obtained in step S1, select the first molecular layer deposition precursor and the second molecular layer deposition precursor to react, and set the deposition process parameters;

[0024] S4. Introducing the first molecular layer deposition precursor vapor from the air inlet pipe into the rotary drum under the inert gas, the first molecular layer deposition precursor vapor is adsorbed on the particle B powder for a holding time of 10 to 120 seconds;

[0025] S5. Purge the rotary drum with an inert gas, introduce the second molecular layer deposition precursor into the rotary drum under the inert gas, react the second molecular layer deposition precursor with the first molecular layer deposition precursor to obtain an organic coating layer, and the reaction time is 10 to 120 seconds;

[0026] S6. Purge the rotary drum with inert gas;

[0027] S7. Repeat the process S4 to S6 until the desired organic coating layer thickness is 10 to 50 nm;

[0028] S8. The rotary drum is evacuated, and the temperature of the heating jacket is increased to the carbonization temperature. After the particles B coated with the organic coating layer are carbonized in a vacuum, the organic coating layer is carbonized to form a conductive carbon layer, thereby obtaining a coated material.

[0029] An ALD operation process includes:

[0030] 1. Pulse the first atomic layer deposition precursor gas from the reaction gas pipeline to expose it to the surface of the particle Q. At the same time, covalent bonds are formed with the first atomic layer deposition precursor gas at the group sites on the surface of the particle Q. The surface sites are saturated into a single layer. Once the surface is saturated, due to the precursor chemistry and process conditions, the excess first atomic layer deposition precursor gas will not react further with the surface of the particle Q.

[0031] 2. The inert carrier gas blows away the remaining unreacted first atomic layer deposition precursor gas and discharges it from the exhaust pipe;

[0032] 3. The pulsed second atomic layer deposition precursor gas chemically reacts on the monolayer surface formed by the first atomic layer deposition precursor gas to obtain the required thin film material;

[0033] 4. The inert carrier gas blows away the remaining second atomic layer deposition precursor gas and reaction byproducts and discharges them from the exhaust pipe.

[0034] The ALD operation process is repeated as many times as needed to allow particle Q to reach the desired coating thickness and become particle B.

[0035] The particle Q is a silicon-based negative electrode material powder, the silicon-based negative electrode material is porous pure silicon or porous silicon monoxide, the first molecular layer deposition precursor is any one of adipoyl chloride, 1,6-hexanediamine, 1,10-diaminodecane, 1,4-dihydroxy-2-butyne, ethylene glycol, propylene glycol or 1,4-benzenediol; the coating layer is a conductive ceramic layer; the conductive carbon layer includes metal oxide and carbon, and the thickness of the conductive ceramic layer is 1 to 10 nm.

[0036] The reactor in step S1 is sized according to the following steps:

[0037] S11. The density of the particles Q coated as required Q and diameter d Q , and the coating density is ρ x The expected diameter d of the particle B formed after the coating layer B , calculate the expected density ρ of particle B B ;

[0038] S12. Obtain the density ρ and viscosity μ of the fluidizing gas containing the reaction precursor at the ALD operating temperature and pressure by looking up the table, and calculate the settling velocity of particle B

[0039] S13. Calculate the lower limit of the diameter D3 of the rotary drum based on the design volume flow rate Fv of the fluidizing gas at the ALD operating temperature and pressure

[0040] S14. Determine the value range of the fluidizing cavity diameter D4, the fluidizing cavity height h1 and the conical cavity height h2 according to the following conditions:

[0041] D4 is less than

[0042] A=0.25×π×(D4) 2 , m is the mass of particles Q loaded in the fluidizing chamber;

[0043]

[0044] ε=0.33~0.5;

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention can sequentially carry out atomic layer deposition technology to coat the conductive ceramic layer, then carry out molecular deposition to coat the carbon material, and high-temperature carbonization process in the device, without the need to remove the intermediate product in the middle, thus realizing continuous operation, reducing the space occupied by intermediate equipment and equipment, and also reducing the energy consumption of the intermediate process. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A half-section view of the overall structure of the device of the present invention;

[0047] Figure 2 This is a schematic diagram of the structure of the feed end during the atomic layer deposition reaction;

[0048] Figure 3 Schematic diagram of the gas generation device during molecular layer deposition reaction. DETAILED DESCRIPTION

[0049] The drawings are only used for illustrative purposes and cannot be understood as limiting the present invention; in order to better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted; the positional relationships described in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. The present invention is further described in detail below in conjunction with specific embodiments.

[0050] like Figure 1-3As shown, a device for continuous atomic layer and molecular layer deposition includes a heating sleeve 2 and a reactor arranged on a bottom plate 8, bearing supports 7 are installed on the left and right ends of the heating sleeve 2, and the reactor includes a rotating cylinder 3 and a left-side reducing tube 4a and a right-side reducing tube 4b, wherein the rotating cylinder 3 is sleeved inside the heating sleeve 2, and when sleeved, the two are clearance-matched, and the left and right ends of the rotating cylinder 3 are connected to the reducing tube 4a / 4b, and the two reducing tubes 4a / 4b pass through the two ends of the heating sleeve 2 respectively and are rotatably connected to the bearing supports 7.

[0051] Preferably, one end of the left-side reduced diameter tube 4a extending out of the heating sleeve 2 is connected to one end of the air inlet hood 5, and a flow equalizing plate 13 is provided at the other end of the air inlet hood 5 away from the rotating drum 2. The flow equalizing plate 13 divides the air inlet hood 5 into a fluidizing chamber 14 close to the rotating drum 3 and an air inlet chamber 15 away from the rotating drum 3. A stirring paddle 16 is installed in the fluidizing chamber 14, and a motor 17 is installed at the end of the air inlet hood 5 facing away from the rotating drum 3. The output shaft of the motor 17 passes through the flow equalizing plate 13 and the air inlet chamber 15 to drive the stirring paddle 16 to rotate. The stirring paddle 16 can make the reaction raw materials and the settled particles B flow, thereby not hindering the input of atomic layer deposition precursor gas. The air inlet chamber 15 is also connected to a plurality of air inlet connectors 18, and the air inlet connectors 18 are detachably connected to the reaction gas pipelines, and the reaction gas pipelines are used to input atomic layer deposition precursor gas and inert gas.

[0052] Preferably, one end of the rotating drum 3 close to the air inlet hood 5 is constructed as a conical cavity 24 which gradually expands from the reducing tube 4a toward the rotating drum 3. The cross-sectional areas of the middle section of the rotating drum 3 at different distances relative to the air inlet hood 5 are equal. The reducing tube 4a is a columnar body of equal diameter along the axial direction. The inner wall of the rotating drum 3 is evenly provided with lifting plates 19 along the circumferential direction. The lifting plates 19 are parallel to the axis of the rotating drum 3, so as not to hinder the atomic layer deposition precursor gas from fluidizing the reaction raw materials in the rotating drum 3. The height of the lifting plates 19 is lower than the distance between the outlet of the air inlet pipe 11 and the inner wall of the rotating drum 3.

[0053] Preferably, one end of the right-side reducer 4b extending out of the heating sleeve 2 is connected to the rotating sleeve 6, and a sleeve 9 is provided inside the reducer 4b. One end of the sleeve 9 extends out from the reducer 4b and is rotatably connected to the rotating sleeve 6, and the other end of the sleeve 9 extends into the rotating cylinder 3; the sleeve 9 is assembled in the rotating sleeve 6, and a shaft seal assembly is arranged between the two. The shaft seal assembly is a common sealing assembly in the prior art, which prevents the gas in the reaction chamber from leaking from the rotating shaft. The sleeve 9 is wrapped around the outer periphery of the exhaust pipe 10 and the intake pipe 11. A filter 12 is provided at one end of the exhaust pipe 10 located in the rotating cylinder 3, and the end of the exhaust pipe 10 located outside the rotating cylinder 3 is connected to the differential electrochemical mass spectrometer and the vacuum pump in sequence; one end of the intake pipe 11 located in the rotating cylinder 3 is bent toward the bottom plate 8, and the other end located outside the rotating cylinder 3 is connected in parallel with different precursor gas supply pipes 25, and the precursor gas supply pipe 25 is used to input molecular layer deposition precursor gas and inert gas.

[0054] Preferably, the bottom plate 8 is equipped with a driving device for driving the rotating drum 3 to rotate; the side of the bottom plate 8 close to the rotating sleeve 6 is connected to the bottom of the base 21 through a telescopic mechanism 20, and the side of the bottom plate 8 close to the air inlet hood 5 is connected to the upper part of the base 21 through a hinge 22. The telescopic mechanism 20 can be used to drive the bottom plate 8 to rotate relative to the hinge 22. When the central axis of the rotating drum 3 is perpendicular to the horizontal plane, the rotating drum 3 is in a position for the atomic layer deposition process. When the central axis of the rotating drum 3 is parallel to the horizontal plane, the rotating drum 3 is in a position for the molecular deposition and carbonization process.

[0055] Furthermore, when the rotary drum 3 is in the working position for the atomic layer deposition process, the central axis of the reactor is perpendicular to the horizontal plane. At this time, the fluidizing chamber 14 and the reducing tube 4a of the air inlet hood 5 are used to fill the particles Q to be coated; the conical chamber 24 is used to provide a larger space to accommodate the coating of the fluidized particles. The conical structure of the conical chamber 24 increases the gap between the particles Q in the conical chamber 24, and the particles Q are more dispersed, and it is not easy to form a system of secondary particle agglomeration, thereby increasing the contact area between the particles Q and the precursor carried by the fluidizing gas, which is conducive to the formation of a uniform coating layer on the surface of the particles Q; the rotary drum 2 is located at the upper end of the lower conical chamber 24, and the fluidizing gas carrying the reaction gas enters the fluidizing chamber 14 from the air inlet joint 18 to the rotary drum 3, and fluidizes and coats the particles Q filled in the fluidizing chamber 14 and the reducing tube 4a. After the coating layer is coated, the particles B that reach the expected size settle back to the fluidizing chamber 4a along the side wall.

[0056] The diameter of particle Q is d Q , the density is ρ Q , the diameter of particle B is d B , the density is ρ B , ρ is the density ρ of the fluidizing gas in the fluidizing chamber 14 and the reducing tube 4a, the conical chamber 24, and the middle section of the rotary drum 3. The fluidizing gas is N2, and the fluidizing gas carries the reaction gas TiCl4 / NH3. The reaction gas reacts with the particles Q to form a coating on the surface of the particles Q. The flow rate of the fluidizing gas in the fluidizing zone 4 is q4, and the cross-sectional area of ​​the fluidizing chamber 14 and the reducing tube 4a is A.

[0057] The empty bed velocity of the fluidizing gas in the fluidizing chamber 14 and the reducing tube 4 is The flow rate of the fluidizing gas in the fluidizing chamber 14 and the reducing tube 4a is u4, ε is the void ratio of the bed when the initial fluidization is formed, ε=0.333~0.5 (the height of the designed fluidized bed is generally 1 / 3~1 / 2 of the volume of the container occupied by mg powder material), u4>u0, u0 is the sedimentation velocity of particle Q, u B is the sedimentation velocity of particle B, u4 B ​The particles Q to be coated are carried out to the conical cavity 24 by the fluidizing gas in the fluidizing cavity 14 and the reducing tube 4, and the particles B coated with the coating layer can settle back to the fluidizing cavity 14 and the reducing tube 4a. μ is the viscosity of the fluidizing gas containing the reaction gas.

[0058] The diameters of the fluidizing chamber 14 and the reducing tube 4a are D4, the diameter of the lower end of the conical chamber 24 is equal to the diameter of the reducing tube 4a, and the diameter of the upper end of the conical chamber 24 is D3, so the empty bed velocity of the fluidizing gas at the upper end of the conical chamber 24 is

[0059] u mf1 <u4, is the initial fluidization velocity of particle Q, is the initial fluidization velocity of particle B, u mf2 >u mf1 .

[0060] The diameter D3 of the conical cavity 24 is not less than Fv is the volume flow rate of the fluidizing gas at the operating temperature and pressure. D4 is the set diameter of the fluidizing chamber 14 and the reducing tube 4, and A is the cross-sectional area of ​​the fluidizing chamber 14 and the reducing tube 4a.

[0061] During the design, the viscosity of the fluidizing gas can be obtained by looking up the table according to the geometric mean diameter and apparent density of the particles Q, the expected diameter and expected density of the particles B after coating, and the temperature and pressure of the ALD atomic layer deposition reaction, and the settling velocity of the particles B and the settling velocity of the particles Q can be calculated. Then, the minimum value of the diameter of the middle section of the rotary drum 3 can be calculated according to the operating flow rate of the fluidizing gas in the atomic layer deposition reaction. Finally, the initial height of the bed layer in which the particles Q form an initial fluidized state from the fluidizing chamber 14 to the rotary drum 3 can be calculated according to the porosity range of the bed when the particles Q form the initial fluidization, the mass of the particles Q loaded in the rotary drum 3, and the set diameters of the fluidizing chamber 14 and the reducing tube 4a.

[0062] The sum of the height h1 of the fluidizing chamber 14 and the reducing tube 4a and the height h2 of the conical chamber 24 is set to be not less than h1 is set to be less than m is the preset mass of the particles Q loaded in the rotary drum 3, A = 0.25 × π × (D4) 2 , m is the mass of particles Q loaded in the fluidizing chamber 14;

[0063] and

[0064] A deposition device within the determined value range of D3, D4, h1, and h2 is selected, and when the rotary drum 3 is in the station for the atomic layer deposition process, atomic layer deposition (ALD) is performed. Specifically, the particle Q to be coated is porous silicon oxide with a pore size of 10 to 50 nm. The particle Q is placed in the fluidizing chamber 14, and then the air inlet hood 5 is installed on the reducing tube 4a. The rotary drum 3 is evacuated and nitrogen is replaced at least three times to remove oxygen and water between the particles Q or in the pores to avoid reaction between residues and reaction gases. The rotary drum 3 is heated to 150°C and maintained at a pressure of 10 torr. TiCl4 vapor is introduced into the rotary drum 3 under the N2 flow rate of 50 sccm. The TiCl4 vapor is adsorbed on the surface of the porous silicon oxide and the inner wall surface of the pores until the air pressure of the rotary drum 3 reaches 10 torr and is maintained for 60 seconds. Then, 50 sccm is used to heat the rotary drum 3. N2 is purged and takes away the remaining TiCl4, and the N2 purging time is 30 seconds. Similarly, NH3 is pulsed into the rotary drum 3 under the influence of 50sccm N2 until the gas pressure reaches 10torr and is maintained for 60 seconds, and reacts with the TiCl4 that has been chemically adsorbed on the particles for 60 seconds. Subsequently, the excess NH3 and by-products are purged out of the rotary drum 3 by 50sccmN2, and the purging time is 30 seconds. In this way, an ALD deposition cycle is completed; the above ALD deposition cycle is repeated to form a 3nm thick TiN coating layer. When the coating thickness reaches the expected size, the silicon-based negative electrode material powder coated with the TiN layer settles back to the fluidizing chamber 14, and the stirring blades 16 in the fluidizing chamber 14 stir the particles, and the fluidizing gas is evenly distributed.

[0065] In the atomic layer deposition step, on the one hand, the gaps between particles B in the fluidized chamber are small, and particles B agglomerate with each other, so it is not easy to react with the atomic layer deposition precursor gas to form a coating layer, and continue to increase in size. On the other hand, the temperature in the fluidized chamber is lower than the ALD operating temperature, and the atomic layer deposition precursor gas is difficult to react with the particle surface, thereby increasing the particle size.

[0066] After completing the atomic layer deposition, operate the telescopic mechanism 20 to rotate the bottom plate 8 around the hinge 22 until the central axis of the rotating drum 3 is parallel to the horizontal plane. At this time, the rotating drum 3 is in the working position for the molecular deposition and carbonization process. The inert gas is input into the fluidizing chamber through the reaction gas pipeline to blow the particles B into the rotating drum. Then, the connection between the reaction gas pipeline and the air inlet connector 18 is disconnected, and the air inlet connector 18 is sealed. The silicon-based negative electrode material powder coated with the TiN layer obtained above is subjected to molecular layer deposition and carbonization treatment.

[0067] Specifically, in a preferred embodiment, when performing molecular layer deposition (MLD), the rotary drum 3 is evacuated and nitrogen is replaced at least three times to remove oxygen and water between particles or in pores to avoid reaction between residues and precursor gases; the rotary drum 3 is heated to 150°C, the rotary drum 3 is maintained at a pressure of 10 torr, and the rotary drum 3 is kept rotating by a driving device, and the first precursor trimethylaluminum for molecular layer deposition is pulsed into the rotary drum 3 from the air inlet pipe 11 under the N2 flow rate of 50 sccm, and adsorbed on the silicon-based negative electrode material powder coated with the TiN layer until the air pressure of the rotary drum 3 reaches 10 torr and is maintained for 60 seconds, and then 50 sccm N2 is used to purge and take away the remaining trimethylaluminum, and the N2 purge time is 30 s. Similarly, the second precursor hydroquinone is carried at a flow rate of 50 sccm The N2 pulse enters the rotary drum 3 from the air inlet pipe until the pressure reaches 10torr and is maintained for 60 seconds, and reacts with the trimethylaluminum on the silicon-based negative electrode material powder coated with the TiN layer for 60 seconds. Then, the excess hydroquinone and by-products are purged out of the rotary drum 3 by 50sccm N2 for 30 seconds, thus completing an MLD deposition cycle; the above MLD deposition cycle is repeated 8 times. During the molecular layer deposition process, the rotary drum 3 is kept rotating by the driving device, and the powder in the fluidized chamber enters the rotary drum. The lifting plate 19 can make the particles uniformly contact with the precursor to react to form a coated silicon-based @TiN negative electrode material.

[0068] The silicon-based @TiN negative electrode material finally obtained after molecular layer deposition (MLD) is subjected to high-temperature carbonization treatment: the rotary drum 3 is evacuated, the temperature of the heating sleeve 2 is increased, the temperature of the rotary drum 3 is raised to 800°C, and the rotary drum 3 is kept rotating by a driving device. The silicon-based @TiN negative electrode material after molecular layer deposition is placed in a vacuum and uniformly contacts the inner wall of the rotary drum 3. It is carbonized at 800°C for 4 hours, and the organic coating layer is carbonized to form a mixture layer of conductive carbon and aluminum oxide. The silicon-based @TiN negative electrode material layer is covered with a mixture of conductive carbon and aluminum oxide.

[0069] The temperature of the heating jacket 2 is lowered, and the rotating drum 3 is kept rotating, so that the high-temperature particles are in uniform contact with the rotating drum 3 for heat transfer until the rotating drum 3 is cooled to room temperature. Then the telescopic mechanism 20 is operated to rotate the bottom plate 8 around the hinge 22, and the central axis of the rotating drum 3 is vertical relative to the horizontal plane. The air inlet cover 5 is removed, and the particles coated by atomic layer deposition and molecular layer deposition are taken out.

[0070] This embodiment is only an example and should not be regarded as limiting the scope of protection of the claims of the present invention. Without departing from the principle and spirit of the present invention, any modification, equivalent substitution and improvement should be regarded as within the scope of protection of the claims of the present invention. For example, different organic coating materials, organic-inorganic composite coating materials can be selected according to specific requirements, and parameters such as the temperature and time of the high-temperature carbonization treatment can be adjusted.

Claims

1. A device for continuous atomic layer and molecular layer deposition, characterized in that: The invention comprises a heating jacket (2) and a reactor arranged on a bottom plate (8), wherein the left and right ends of the heating jacket (2) are provided with bearing supports (7), and the reactor comprises a rotating drum (3) and a reducing tube (4a, 4b), wherein the rotating drum (3) is sleeved inside the heating jacket (2), and when the rotating drum (3) and the reducing tube (4a, 4b) are sleeved together, the left and right ends of the rotating drum (3) are connected to the reducing tube (4a, 4b), and the reducing tube (4a, 4b) extends from the heating jacket (2) and is rotatably connected to the bearing supports (7); One end of the left-side reduced diameter tube (4a) extending out of the heating jacket (2) is connected to the air intake hood (5); a flow equalizing plate (13) is provided on the side of the air intake hood (5) away from the rotary drum (3); the flow equalizing plate (13) divides the air intake hood (5) into a fluidizing chamber (14) close to the rotary drum (3) and an air intake chamber (15) away from the rotary drum (3); and atomic layer deposition precursor gas and inert gas are introduced into the rotary drum (3) through the air intake chamber (15); One end of the rotary drum (3) close to the air inlet hood (5) is constructed as a tapered cavity (24) that gradually expands from the reduced diameter pipe (4a) toward the rotary drum (3); the cross-sectional areas of the middle section of the rotary drum (3) at different distances relative to the air inlet hood (5) are equal; and the reduced diameter pipe (4a) is a cylindrical body with equal diameter along the axial direction; One end of the right-side reducing tube (4b) extending out of the heating sleeve (2) is connected to the rotating sleeve (6); a sleeve (9) is provided inside the reducing tube (4b); one end of the sleeve (9) extends out of the reducing tube (4b) and is rotatably connected to the rotating sleeve (6); the other end of the sleeve (9) extends into the rotating cylinder (3); a shaft seal assembly is provided between the sleeve (9) and the rotating sleeve (6); an exhaust pipe (10) and an air inlet pipe (11) are provided inside the sleeve (9); molecular layer deposition precursor gas and inert gas are introduced into the rotating cylinder (3) through the air inlet pipe (11); The bottom plate (8) is provided with a driving device for driving the rotating drum (3) to rotate; the bottom plate (8) is connected to the base (21) via a hinge (22) on a side close to the air inlet hood (5); the bottom plate (8) is also connected to a telescopic mechanism (20); the telescopic mechanism (20) can be used to drive the bottom plate (8) to rotate relative to the hinge (22); when the central axis of the rotating drum (3) is perpendicular to a horizontal plane, the rotating drum (3) is in a position for an atomic layer deposition process; when the central axis of the rotating drum (3) is parallel to a horizontal plane, the rotating drum (3) is in a position for a molecular deposition and carbonization process.

2. The device for continuous atomic layer and molecular layer deposition according to claim 1, characterized in that: A stirring paddle (16) is installed in the fluidizing chamber (14); a motor (17) is installed at one end of the air intake hood (5) facing away from the rotary drum (3); an output shaft of the motor (17) passes through the flow equalizing plate (13) and the air intake chamber (15) and is used to drive the stirring paddle (16) to rotate; the air intake chamber (15) is connected to an air intake connector (18); the air intake connector (18) is detachably connected to a reaction gas pipeline; the reaction gas pipeline is used to input atomic layer deposition precursor gas and inert gas.

3. The device for continuous atomic layer and molecular layer deposition according to claim 1, characterized in that: The inner wall of the rotating drum (3) is evenly provided with lifting plates (19) in the circumferential direction. The lifting plates (19) are parallel to the axis of the rotating drum (3) so as not to hinder the atomic layer deposition precursor gas from fluidizing the reaction raw materials in the rotating drum (3). The height of the lifting plates (19) is lower than the distance between the outlet of the air inlet pipe (11) and the inner wall of the rotating drum (3).

4. The device for continuous atomic layer and molecular layer deposition according to claim 1, characterized in that: The end of the exhaust pipe (10) located inside the rotating drum 3 is provided with a filter (12), and the end of the exhaust pipe (10) located outside the rotating drum (3) is connected to the differential electrochemical mass spectrometer and the vacuum pump in sequence; the end of the inlet pipe (11) located inside the rotating drum (3) is bent toward the bottom plate (8), and the end located outside the rotating drum (3) is connected in parallel to different precursor gas supply pipelines (25), and the precursor gas supply pipelines (25) are used to input molecular layer deposition precursor gas and inert gas.

5. The device for continuous atomic layer and molecular layer deposition according to claim 1, characterized in that: One end of the telescopic mechanism (20) is connected to the lower part of the base (21), and the other end is connected to the part of the bottom plate (8) close to the rotating sleeve (6). The side of the bottom plate (8) close to the air intake cover (5) is connected to the upper part of the base (21) via a hinge (22). The telescopic mechanism (20) is used to drive the bottom plate (8) to rotate relative to the hinge (22).

6. The device for continuous atomic layer and molecular layer deposition according to claim 1, characterized in that: When the rotating drum (3) is in a working position for an atomic layer deposition process, the fluidizing chamber (14) of the reducing tube (4a) is filled with particles Q to be coated, and the rotating drum (3) is used to allow particles B that have reached a desired size after being coated with a coating layer to settle back into the fluidizing chamber (14); wherein: The diameter D3 of the rotary drum (3) is not less than Fv is the design volume flow rate of fluidizing gas at the operating temperature and pressure of the device, d B and ρ B are the expected diameter of particle B and the density of particle B when it reaches the expected diameter, respectively; ρ and μ are the density and viscosity of the fluidizing gas containing the reaction precursor output from the reaction gas pipeline at the operating temperature and pressure of the device, respectively; the diameter D4 of the fluidizing chamber (14) is smaller than D'; the density of particle Q is ρ Q , the diameter of particle Q before coating is d Q , ε=0.33-0.5, the sum of the axial height h1 of the fluidizing chamber (14) and the reducing tube (4a) and the axial height h2 of the tapered chamber (24) is set to be not less than h1 is set to be less than The sum of the volumes of the fluidizing chamber (14) and the conical chamber (24) is designed to be 1 / ε times the bulk volume of the particles Q filled in the fluidizing chamber (14), A = 0.25 × π × (D4) 2 , m is the mass of particles Q loaded in the fluidizing chamber (14).

7. A method for continuous atomic layer and molecular layer deposition, based on the device for continuous atomic layer and molecular layer deposition according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. When the rotary drum (3) is in the working position of the atomic layer deposition process, the particles Q with a mass of m are loaded into the fluidizing chamber (14) of the disassembled inlet hood (5), and then the inlet hood (5) is installed on the retracting tube (4a), and the rotary drum (3) is evacuated and the inert gas is replaced at least three times, and the pressure of the fluidizing chamber (14) is controlled to reach the ALD operating pressure, and then the temperature of the heating jacket (2) is controlled to make the rotary drum (3) reach the ALD operating temperature, and the ALD operation process is repeated multiple times to input the inert gas with a volume flow rate of Fv and containing the atomic layer deposition precursor gas into the fluidizing chamber (14) through the reaction gas pipeline, so that the particles Q are coated with the coating layer to form a desired diameter d B Particles B are deposited back into the fluidizing chamber (14); S2. After the atomic layer deposition is completed, the telescopic mechanism (20) is operated to make the central axis of the rotary drum (3) parallel to the horizontal plane, the rotary drum (3) is in a position for the molecular deposition and carbonization process, an inert gas is input into the fluidizing chamber (14) through the reaction gas pipeline, the particles B are blown into the rotary drum (3), and then the connection between the reaction gas pipeline and the air inlet joint (18) is disconnected, and the air inlet joint (18) is blocked; S3. According to the type of particles B obtained in step S1, select the first molecular layer deposition precursor and the second molecular layer deposition precursor to react, and set the deposition process parameters; S4. Introducing the first molecular layer deposition precursor vapor from the air inlet pipe (11) into the rotary drum (3) under the inert gas, the first molecular layer deposition precursor vapor is adsorbed on the particle B powder for a retention time of 10 to 120 seconds; S5. Purge the rotary drum (3) with an inert gas, introduce the second molecular layer deposition precursor into the rotary drum (3) under the inert gas, and react the second molecular layer deposition precursor with the first molecular layer deposition precursor to obtain an organic coating layer, and the reaction time is 10 to 120 seconds; S6. Purge the rotary drum (3) with an inert gas; S7. Repeat the process S4 to S6 until the desired organic coating layer thickness is 10 to 50 nm; S8. The rotary drum (3) is evacuated, and the temperature of the heating jacket (2) is increased to the carbonization temperature. After the particles B coated with the organic coating layer are carbonized in a vacuum, the organic coating layer is carbonized to form a conductive carbon layer, thereby obtaining a coated material.

8. The method for continuous atomic layer and molecular layer deposition according to claim 7, characterized in that: The particle Q is a silicon-based negative electrode material powder, the silicon-based negative electrode material is porous pure silicon or porous silicon monoxide, the first molecular layer deposition precursor is any one of adipoyl chloride, 1,6-hexanediamine, 1,10-diaminodecane, 1,4-dihydroxy-2-butyne, ethylene glycol, propylene glycol or 1,4-benzenediol; the coating layer is a conductive ceramic layer; the conductive carbon layer includes metal oxide and carbon, and the thickness of the conductive ceramic layer is 1 to 10 nm.

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