WO2025232636A1 - Device and method for continuous atomic layer deposition coating of powder - Google Patents

Abstract

Disclosed in the present invention are a device and method for continuous atomic layer deposition (ALD) coating of powder. The device comprises a plurality of ALD growth cycle units connected in series. Continuous atomic layer deposition is achieved by means of multiple reactions. Each ALD cycle unit comprises a first reactor and a second reactor which can respectively implement reactions of different precursors, thereby shortening the waiting time for cleaning in the same reaction chamber. Each technological process can be conducted individually, saving time, reducing production costs, improving production efficiency, and featuring a simple structure.

Description

An apparatus and method for continuous atomic layer deposition coating powder Technical Field

This invention relates to the field of vacuum atomic deposition coating, and more specifically to an apparatus and method for continuous atomic layer deposition coating of powder.

Background Technology

Atomic layer deposition (ALD) is a thin film fabrication technique that grows thin films layer by layer at the atomic level. An ideal ALD growth process involves selectively and alternately exposing different precursors to the surface of a substrate, where they are chemically adsorbed and react to form the deposited thin film.

A complete ALD growth cycle can be divided into four steps:

1. The first precursor is exposed on the substrate surface by a pulse, and covalent bonds are formed between the first precursor and the group sites on the substrate surface. The surface sites are saturated into a monolayer. Once the surface is saturated, due to the precursor chemistry and process conditions, the excess precursor will not react further with the substrate surface.

2. Inert carrier gas blows away the remaining unreacted precursors;

3. The second precursor undergoes a chemical reaction on the surface of the monolayer formed by the first precursor to obtain the desired thin film material;

4. The remaining precursors and reaction byproducts are blown away by an inert carrier gas.

Atomic layer deposition typically involves a cycle of the above four steps, repeated multiple times as needed to achieve the desired coating thickness. During growth, the surface is alternately exposed to two complementary chemical precursors. In this case, each precursor is fed into the reactor separately. To prevent the precursors from reacting anywhere outside the surface, thus preventing chemical vapor deposition (CVD), each precursor must be purged with an inert carrier gas after forming a monolayer and becoming saturated on the substrate surface, separating the different precursor deposition steps; this means that the coating after each pulse is self-limited to a single monolayer and allows for the coating of complex shapes with atomic precision.

One ALD growth cycle can form a monolayer coating of 0.1–0.2 nm. To form a coating 10–20 nm thick, 100–200 ALD growth cycles are required. In existing atomic layer deposition (ALD) powder coating technologies, one ALD growth cycle is completed within the reaction chamber. Each purge of the inert support takes 30 seconds to remove the original precursor from the reaction chamber, and re-injecting the precursor to the target pressure also requires time. 100–200 ALD growth cycles require at least 100–200 minutes for purging the inert support and time for re-injecting the precursor to the target pressure. This makes ALD powder coating time too long, failing to improve yield per unit time.

Summary of the Invention

The technical problem to be solved by the present invention is to provide an apparatus for continuous atomic layer deposition coating of powder, which overcomes the current process problems by setting up multiple continuous reaction chambers, and has a simple structure and reasonable design.

A reactor includes: a reaction chamber and a purification chamber, the purification chamber being located below the reaction chamber, a valve device being provided between the reaction chamber and the purification chamber, the valve device being operable between an open position and a closed position, the valve device having a disc, the purification chamber being isolated from the reaction chamber by the disc when the valve device is in the closed position, the disc being configured to include flow equalization holes evenly distributed on the side of the disc facing the reaction chamber, and a fluidizing gas exhaust pipe located inside the disc and communicating with all the flow equalization holes;

The reaction chamber is equipped with a pressure detection device and a temperature sensor. The reaction chamber is equipped with a heating device outside the reaction chamber. The reaction chamber is connected to a differential electrochemical mass spectrometer and a vacuum pump in sequence through a tail gas exhaust pipe. A filter to prevent particle inhalation is provided at the inlet of the tail gas exhaust pipe. The reaction chamber is also connected to the outlet of the feed inlet pipe. The fluidizing gas exhaust pipe is connected to the inlet pipe. The inlet pipe is connected to the common inlet pipe of the reaction gas and the independent inlet pipe attached to the common inlet pipe of the inert carrier gas through a reaction gas exhaust valve and an inert carrier gas exhaust valve, respectively.

The bottom of the purification chamber is connected to the inlet of the material discharge pipe. The purification chamber is also connected to an independent inlet pipe attached to the common inlet pipe of the inert carrier gas through an inert carrier gas exhaust valve. The purification chamber is also connected to the differential electrochemical mass spectrometer and the vacuum pump in sequence through the tail gas pipe.

The disc plate has an exhaust port on the side facing the clean room. The exhaust port is connected in sequence to the inert carrier gas exhaust valve and the independent intake pipe attached to the common inert carrier gas intake pipe through another fluidizing gas exhaust pipe inside the disc plate.

A stirring device is installed in the reaction chamber.

The disc includes an opening and closing device that can operate between blocking the flow equalization orifice and not blocking the flow equalization orifice.

Preferably, the disc includes a shell, inside which a fluidizing gas exhaust pipe is arranged along the central axis of the disc. Multiple independent exhaust pipes are attached to the fluidizing gas exhaust pipe. The beginning of each independent exhaust pipe is connected to the fluidizing gas exhaust pipe, and the end of each independent exhaust pipe is away from and closed off from the fluidizing gas exhaust pipe. Each independent exhaust pipe has uniformly distributed flow equalization holes extending from inside the independent exhaust pipe to the surface of the shell. Each independent exhaust pipe is fitted with a hollow sleeve that can slide along the independent exhaust pipe, and an elastic body or magnetic body capable of applying pressure or tension to the sleeve. The pressure or tension is directed axially towards the fluidizing gas exhaust pipe along the independent exhaust pipe. The pipe is evenly provided with through holes, and the end of the sleeve near the end of the independent exhaust pipe is closed. The length of the independent exhaust pipe is greater than the length of the sleeve inside the independent exhaust pipe. When air is supplied to the independent exhaust pipe, causing the sleeve to overcome the pressure or tension and move away from the fluidized gas exhaust pipe along the axial direction of the independent exhaust pipe until it approaches the end of the independent exhaust pipe, the through holes on the sleeve are aligned one-to-one with the flow equalization holes of the independent exhaust pipe. When air supply to the independent exhaust pipe is stopped or the air pressure is lower than the threshold, the sleeve moves closer to the fluidized gas exhaust pipe along the axial direction of the independent exhaust pipe under the pressure or tension until it approaches the beginning of the independent exhaust pipe, and the sleeve blocks the flow equalization holes of the independent exhaust pipe.

Preferably, the disc includes a housing, inside which a fluidizing gas exhaust pipe is arranged along the central axis of the disc. Multiple independent exhaust pipes are attached to the fluidizing gas exhaust pipe, with the beginning of each independent exhaust pipe connected to the fluidizing gas exhaust pipe and the end of each independent exhaust pipe located away from and not closed. Each independent exhaust pipe has evenly distributed flow equalization holes. The housing has windows aligned with each independent exhaust pipe. Each independent exhaust pipe is fitted with a hollow sleeve that can slide along the independent exhaust pipe. An elastic body or magnetic body capable of applying pressure or tension to the sleeve is provided inside the housing or outside the independent exhaust pipe. The pressure or tension is directed along the axial direction of the independent exhaust pipe towards the fluidizing gas exhaust pipe. Through holes are evenly distributed on the sleeve. The length of the window along the axial direction of the independent exhaust pipe is less than the length of the sleeve and the independent exhaust pipe. The width of the window is not greater than the diameter of the sleeve. The length of the sleeve is less than the shortest distance from the beginning of the independent exhaust pipe inside the sleeve along the axial direction of the independent exhaust pipe to the shell. The length of the sleeve is greater than the length of the independent exhaust pipe inside the sleeve. The end of the sleeve near the end of the independent exhaust pipe is closed. When air is supplied to the independent exhaust pipe, causing the sleeve to overcome pressure or tension and move away from the fluidizing gas exhaust pipe along the axial direction of the independent exhaust pipe until it approaches the end of the independent exhaust pipe, the through hole on the sleeve is aligned one-to-one with the flow equalization hole of the independent exhaust pipe. When air supply to the independent exhaust pipe is stopped or the gas pressure is lower than the threshold, the sleeve moves closer to the fluidizing gas exhaust pipe along the axial direction of the independent exhaust pipe under the pressure or tension until it approaches the beginning of the independent exhaust pipe, and the sleeve blocks the flow equalization hole of the independent exhaust pipe.

An apparatus for continuous atomic layer deposition coating powder includes the reactors described above. Every two reactors form an ALD growth cycle unit. The outlet of the feed outlet of the first reactor is connected to the inlet of the feed inlet of the second reactor. The common inlet pipe of the first reactor is supplied with gas from a first reaction gas source, the common inlet pipe of the second reactor is supplied with gas from a second reaction gas source, and the common inlet pipe of the inert carrier gas is supplied with gas from an inert carrier gas source.

Multiple ALD growth cycle units are connected in series. The inlet of the feed inlet pipe of the first reactor in the first ALD growth cycle unit is connected to the feed tank. Starting from the first ALD growth cycle unit, the outlet of the feed outlet pipe of the second reactor in the ALD growth cycle unit is connected to the inlet of the feed inlet pipe of the first reactor in the next ALD growth cycle unit. The outlet of the feed outlet pipe of the second reactor in the last ALD growth cycle unit is connected to the discharge tank.

An apparatus for continuous atomic layer deposition (ALD) coating powder includes the reactors described above. Every four reactors form an ALD growth cycle unit. The outlet of the feed outlet pipe of the first reactor in the first to fourth reactors is connected to the inlet of the feed inlet pipe of the next reactor. The common inlet pipe of the reaction gas of the first reactor is supplied with gas from a first reaction gas source. The common inlet pipe of the reaction gas of the second and fourth reactors is supplied with gas from a second reaction gas source. The common inlet pipe of the reaction gas of the third reactor is supplied with gas from a third reaction gas source. The common inlet pipe of the inert carrier gas is supplied with gas from an inert carrier gas source.

Multiple ALD growth cycle units are connected in series. The inlet of the feed inlet pipe of the first reactor in the first ALD growth cycle unit is connected to the feed tank. Starting from the first ALD growth cycle unit, the outlet of the feed outlet pipe of the fourth reactor in the ALD growth cycle unit is connected to the inlet of the feed inlet pipe of the first reactor in the next ALD growth cycle unit. The outlet of the feed outlet pipe of the fourth reactor in the last ALD growth cycle unit is connected to the discharge tank.

A method for coating powder using continuous atomic layer deposition (ALD), employing the apparatus described above, includes the following steps:

S1. Using inert carrier gas, the uncoated powder is transported to the reaction chamber of the first reactor in the ALD growth cycle unit. Inert carrier gas is continuously introduced into the reaction chamber of the first reactor to heat the fluidized powder and keep the powder temperature within the preset temperature value.

S2. In the reaction chamber of the first reactor, the powder is pulsed with the first reaction gas to maintain the pressure in the reaction chamber of the first reactor within the target pressure value. The composition of the tail gas discharged from the reaction chamber of the first reactor is detected until it is determined that the first reaction gas is in excess.

S3. If it is determined that the first reaction gas is in excess, discharge the powder into the purification chamber of the first reactor and fill the purification chamber of the first reactor with inert carrier gas until the exhaust gas discharged from the purification chamber of the first reactor does not contain the first reaction gas and by-products.

S4. The powder in the purification chamber of the first reactor is transported to the reaction chamber of the second reactor using inert carrier gas. Inert carrier gas is continuously introduced into the reaction chamber of the second reactor to heat and fluidize the powder, so that the powder temperature is maintained within the preset temperature value.

S5. In the reaction chamber of the second reactor, pulse the second reaction gas into the powder, keep the pressure in the reaction chamber of the second reactor within the target pressure value, and detect the composition of the tail gas discharged from the reaction chamber of the second reactor until it is determined that the second reaction gas is in excess.

S6. When it is determined that the second reaction gas is in excess, the powder is discharged into the purification chamber of the second reactor, and inert carrier gas is introduced into the purification chamber of the second reactor until the exhaust gas discharged from the purification chamber of the second reactor does not contain the second reaction gas and by-products, that is, one ALD growth cycle is completed on the powder surface.

S7. Repeat steps S1 to S6 in the next ALD growth cycle unit to complete multiple ALD growth cycles on the powder surface partially coated in the upstream step until the coating on the powder surface reaches the target thickness.

S8. The coated powder is transported to the feeding tank for cooling using inert carrier gas;

The powder includes uncoated powder or powder partially coated from upstream steps in the coating process.

A method for coating powder using continuous atomic layer deposition (ALD), employing the apparatus described above, includes the following steps:

F1. The uncoated powder is transported to the reaction chamber of the first reactor in the ALD growth cycle unit using an inert carrier gas. The inert carrier gas is continuously introduced into the reaction chamber of the first reactor to heat the fluidized powder and keep the powder temperature within the preset temperature value.

F2. In the reaction chamber of the first reactor, the powder is pulsed with the first reaction gas, and the pressure in the reaction chamber of the first reactor is kept within the target pressure value. The composition of the exhaust gas discharged from the reaction chamber of the first reactor is detected until it is determined that the first reaction gas is in excess.

F3. If it is determined that the first reaction gas is in excess, the powder is discharged into the purification chamber of the first reactor, and inert carrier gas is introduced into the purification chamber of the first reactor until the exhaust gas discharged from the purification chamber of the first reactor does not contain the first reaction gas and by-products.

F4. The powder in the purification chamber of the first reactor is transported to the reaction chamber of the second reactor using an inert carrier gas. The inert carrier gas is continuously introduced into the reaction chamber of the second reactor to heat and fluidize the powder, so that the powder temperature is maintained within the preset temperature value.

F5. In the reaction chamber of the second reactor, pulse the second reaction gas into the powder, keep the pressure in the reaction chamber of the second reactor within the target pressure value, and detect the composition of the tail gas discharged from the reaction chamber of the second reactor until it is determined that the second reaction gas is in excess.

F6. If the second reaction gas is found to be in excess, the powder is discharged into the purification chamber of the second reactor, and inert carrier gas is introduced into the purification chamber of the second reactor until the exhaust gas discharged from the purification chamber of the second reactor does not contain the second reaction gas and by-products.

F7. The powder in the purification chamber of the second reactor is transported to the reaction chamber of the third reactor using inert carrier gas. Inert carrier gas is continuously introduced into the reaction chamber of the third reactor to heat and fluidize the powder, so that the powder temperature is maintained within the preset temperature value.

F8. In the reaction chamber of the third reactor, pulse the third reaction gas into the powder, keep the pressure in the reaction chamber of the third reactor within the target pressure value, and detect the composition of the tail gas discharged from the reaction chamber of the third reactor until it is determined that the third reaction gas is in excess.

F9. If the third reaction gas is found to be in excess, the powder is discharged into the purification chamber of the third reactor, and inert carrier gas is introduced into the purification chamber of the third reactor until the exhaust gas discharged from the purification chamber of the third reactor does not contain the third reaction gas and byproducts.

F10. The powder in the purification chamber of the third reactor is transported to the reaction chamber of the fourth reactor using inert carrier gas. Inert carrier gas is continuously introduced into the reaction chamber of the fourth reactor to heat the fluidized powder and keep the powder temperature within the preset temperature value.

F11. In the reaction chamber of the fourth reactor, the powder is pulsed with the second reaction gas to maintain the pressure in the reaction chamber of the fourth reactor within the target pressure value. The composition of the exhaust gas discharged from the reaction chamber of the fourth reactor is detected until it is determined that the second reaction gas is in excess.

F12. When it is determined that the second reaction gas is in excess, the powder is discharged into the purification chamber of the fourth reactor, and inert carrier gas is introduced into the purification chamber of the fourth reactor until the exhaust gas discharged from the purification chamber of the fourth reactor does not contain the second reaction gas and by-products, that is, one ALD growth cycle is completed on the powder surface.

F13. Repeat steps F1 to F12 in the next ALD growth cycle unit to complete multiple ALD growth cycles on the powder surface partially coated in the upstream step until the coating on the powder surface reaches the target thickness.

F14. The coated powder is transported to the feeding tank for cooling using inert carrier gas;

The powder includes uncoated powder or powder partially coated from upstream steps in the coating process.

Furthermore, the excess of the first, second, or third reaction gas is determined by the following steps:

The concentrations C1 of the first/second/third reactant gas in the exhaust gas and the concentrations C2 of the byproducts generated by the reaction of the first/second/third reactant gas with the powder are detected.

The excess of the first, second, or third reaction gas is determined based on whether C2 and C1 meet the discrimination criteria.

The criteria for determining whether the first, second, or third reactant gas is in excess include:

C1 is not less than the first threshold, but C2 is not greater than the second threshold.

The beneficial effects of the present invention are as follows: Firstly, it includes multiple ALD growth cycle units connected in series, which can complete continuous atomic layer deposition, and each ALD cycle unit is divided into multiple reactors, which can react with different precursors respectively, thereby reducing the time for replacing precursors in the same reaction chamber. In this invention, when the purification chamber of the previous reactor discharges powder to the next reaction chamber, since the gas carrying the powder into the reaction chamber is an inert gas, the powder does not need to be purged and replaced after entering the new reaction chamber. When the reaction chamber discharges powder into the purification chamber, since only inert gas permeates into the reaction chamber, it is not necessary to purge and replace the gas in the reaction chamber. Furthermore, since the process of powder falling from the reaction chamber into the purification chamber is a process of gas and powder volume exchange, the pulse reaction gas time in the reaction chamber is short, the residual reaction gas content is small, and the reaction gas carried into the purification chamber with the powder is small. The volume of the purification chamber is approximately equal to the total volume of the powder in the reaction chamber. After the powder is discharged into the purification chamber, very little gas is carried in. By introducing a small amount of inert gas to extract the residual gas, the gas in the purification chamber can be replaced in a very short time. Therefore, the entire ALD growth cycle saves the time of replacing the precursor gas in the reaction chamber, and the time saved by 100 ALD growth cycles is greater than 1 hour.

Secondly, the reaction chamber does not require repeated replacement of the precursor gas, and the volume of inert gas used for purging in the purification chamber each time is much smaller than the capacity of the reaction chamber, thus saving the amount of inert gas used for purging.

Thirdly, a valve device can be used to isolate the reaction chamber and the cleanroom, allowing powder to be discharged from the reaction chamber to the cleanroom, and also to fluidize the powder within the reaction chamber. Fluidizing the powder within the reaction chamber results in a more uniform atomic layer deposition layer on the powder surface. Currently, there is no device that can both fluidize the powder within the reaction chamber and discharge it from the reaction chamber.

Fourthly, because the valve device has multiple independent exhaust pipes attached to the fluidizing gas exhaust pipe, the beginning of each independent exhaust pipe is connected to the fluidizing gas exhaust pipe, and the end of each independent exhaust pipe is away from the fluidizing gas exhaust pipe. Each independent exhaust pipe has evenly distributed flow equalization holes. Each independent exhaust pipe has a hollow sleeve that can slide along it, either inside or outside the sleeve, and an elastic or magnetic body that can apply pressure or tension to the sleeve. This pressure or tension is directed axially towards the fluidizing gas exhaust pipe. The sleeve has evenly distributed through holes. When air is supplied to the independent exhaust pipe, causing the sleeve to overcome the pressure or tension and move axially away from the fluidizing gas exhaust pipe until it approaches the end of the independent exhaust pipe, the through holes on the sleeve and the flow equalization holes of the independent exhaust pipe... The holes are aligned one by one, and the gas is discharged into the reaction chamber through the independent exhaust pipe. When the gas supply to the independent exhaust pipe is stopped or the gas pressure is lower than the threshold, the sleeve moves along the axial direction of the independent exhaust pipe towards the fluidizing gas exhaust pipe until it reaches the beginning of the independent exhaust pipe. The through holes on the sleeve are staggered with the flow equalization holes of the independent exhaust pipe. The gas stops being discharged into the reaction chamber through the independent exhaust pipe, and the powder in the reaction chamber stops fluidizing and falls onto the surface of the valve device. The sleeve can effectively intercept the powder from entering the independent exhaust pipe or the fluidizing gas exhaust pipe, which would block the flow equalization holes and affect the powder fluidization and coating effect, or cause the powder with saturated surface sites to re-enter the reaction chamber. However, the introduction of reaction gas prevents the powder from reacting with the reaction gas, resulting in the waste of reaction gas.

Attached Figure Description

Figure 1 is a structural diagram of an apparatus for continuous atomic layer deposition coating of powder according to the present invention;

Figure 2 is another structural diagram of the apparatus for continuous atomic layer deposition coating powder according to the present invention;

Figure 3 is a structural diagram of a valve device;

Figure 4 is a magnified view of the upper part of Figure 3;

Figure 5 shows another structural diagram of the valve device.

Figure 6 is a magnified view of the upper part of Figure 5.

Embodiments of the present invention

The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

As shown in Figure 1, an apparatus for continuous atomic layer deposition coating powder includes multiple ALD growth cycle units 3 connected in series by pipes. Each ALD growth cycle unit 3 includes a first reactor 1 and a second reactor 2 connected in series. Both the first reactor 1 and the second reactor 2 include a reaction chamber 4 and a purification chamber 5, with the purification chamber 5 located below the reaction chamber 4.

Preferably, the reaction chamber 4 is also equipped with a temperature detector and a pressure detector, as well as a stirring device 7 at the top of the reaction chamber. The blades of the stirring device 7 extend to the bottom of the reaction chamber. The pressure detector can monitor the pressure value inside the reaction chamber in real time. A heating device 8 is installed on the outer side of the lower part of the reaction chamber. Each reaction chamber is connected to the inlet of a differential electrochemical mass spectrometer 10 through a tail gas exhaust pipe 9. The outlet of the differential electrochemical mass spectrometer 10 is connected to a vacuum pump 11. A filter device 12 is installed at the inlet of the tail gas exhaust pipe 9 to prevent powder from flowing out of the reaction chamber along the tail gas. The side of the reaction chamber is also connected to the inlet of the feed inlet pipe 13, and the bottom of the purification chamber is connected to the inlet of the feed outlet pipe 14. Vacuum valves, including butterfly valves or gate valves, are installed on both the feed inlet pipe 13 and the feed outlet pipe 14. Each purification chamber is also connected to the differential electrochemical mass spectrometer 10 and the vacuum pump 11 in sequence through a tail gas pipe. The capacity of the lower part of the reaction chamber is greater than the capacity of the purification chamber.

Preferably, a valve device is provided between the reaction chamber 4 and the purification chamber 5. The valve device can be operated between an open position and a closed position. The valve device has a disc 6. When the valve device is in the closed position, the purification chamber 5 and the reaction chamber 4 are isolated by the disc 6. The disc 6 includes flow equalization holes evenly distributed on the side of the disc facing the reaction chamber. Each flow equalization hole is connected to a fluidizing gas exhaust pipe inside the disc. The flow equalization holes can be used to evenly disperse the fluidizing gas and fluidized powder. The fluidizing gas exhaust pipe inside the disc 6 is connected to the inlet pipe 15. The inlet pipe 15 is connected to the independent inlet pipe attached to the common inlet pipe of the reaction gas (21a or 21b) and the common inlet pipe of the inert carrier gas 20 through the reaction gas exhaust valve 16 and the inert gas exhaust valve 17.

Preferably, the disc plate 6 is also provided with an exhaust port on the side facing the clean room 5. The exhaust port is connected in sequence to the inert carrier gas exhaust valve 18 and the independent intake pipe attached to the inert carrier gas common intake pipe 20 through another fluidizing gas exhaust pipe inside the disc plate 6.

To improve temperature uniformity, the inert gas introduced into the first reactor 1 or the second reactor 2 can be preheated. The stirring device 7, through stirring, can make the temperature of the heated powder more uniform and facilitate fluidization. Its blades can be simple rod-shaped structures, fan-shaped structures, etc. The gas pressure monitoring device is used to monitor the gas pressure value inside the reaction chamber in real time and decide whether to introduce inert gas or reaction gas from the fluidizing gas inlet pipe, and the amount of gas introduced. The heating device 8 installed outside the reaction chamber can be used to heat the fluidized powder.

Furthermore, the disc plate 6 is made of heat-resistant material, which can be a porous sintered plate made of stainless steel powder. The diameter of the flow equalization holes is selected according to the particle size of the powder to be coated. While being as large as possible to facilitate airflow, it can effectively intercept the powder and prevent the powder from entering or falling into the disc plate 6.

Preferably, the disc plate 6 includes an opening and closing device that can operate between blocking the flow equalization orifice and not blocking the flow equalization orifice.

As a preferred embodiment, as shown in Figure 3, and Figure 4 being a partial enlarged view of the upper part of Figure 3, the disc plate 6 includes a housing 64. A fluidizing gas exhaust pipe 61 is disposed within the housing along the central axis of the disc plate 6. Multiple independent exhaust pipes 62 are attached to the fluidizing gas exhaust pipe 61. The beginning of each independent exhaust pipe 62 is connected to the fluidizing gas exhaust pipe, and the end of each independent exhaust pipe is far from and closed off from the fluidizing gas exhaust pipe. Each independent exhaust pipe 62 has uniformly distributed flow equalization holes 63 extending from inside the independent exhaust pipe to the surface of the housing 64. Each independent exhaust pipe 62 is fitted with a hollow sleeve 65 that can slide along the independent exhaust pipe, and an elastic body 66 or magnetic body capable of applying pressure or tension to the sleeve 65. This pressure or tension is directed axially along the independent exhaust pipe 62 towards the fluidizing gas exhaust pipe 61. The sleeve 65 has uniformly distributed through holes 67, and the end of the sleeve 65 near the end of the independent exhaust pipe 62 is closed. The length of the independent exhaust pipe 62 is greater than that of the independent exhaust pipe. The sleeve, with a length of 65 within 62, allows air to be supplied to the independent exhaust pipe. When the sleeve overcomes pressure or tension and moves axially away from the fluidizing gas exhaust pipe until it approaches the end of the independent exhaust pipe, the through holes on the sleeve align one-to-one with the flow equalization holes of the independent exhaust pipe. Gas is discharged into the reaction chamber from the independent exhaust pipe. When air supply to the independent exhaust pipe stops or the gas pressure is below the threshold, the sleeve moves axially towards the fluidizing gas exhaust pipe until it approaches the beginning of the independent exhaust pipe under the pressure or tension. The sleeve blocks the flow equalization holes of the independent exhaust pipe outside the sleeve, and gas stops being discharged into the reaction chamber from the independent exhaust pipe. The powder in the reaction chamber stops fluidizing and falls onto the surface of the valve device. The sleeve can effectively intercept powder from entering the independent exhaust pipe or the fluidizing gas exhaust pipe, which could block the flow equalization holes, affecting powder fluidization and coating effects, or cause powder with saturated surface sites to re-enter the reaction chamber. However, the supplied reaction gas prevents the powder from reacting with the reaction gas, resulting in waste of the reaction gas.

As another preferred embodiment, as shown in Figure 5, and Figure 6 being a partial enlarged view of the upper part of Figure 5, the disc plate 6 includes a housing 64. A fluidizing gas exhaust pipe 61 is arranged inside the housing along the central axis of the disc plate 6. Multiple independent exhaust pipes 62 are attached to the fluidizing gas exhaust pipe 61. The beginning of each independent exhaust pipe is connected to the fluidizing gas exhaust pipe, and the end of each independent exhaust pipe is away from the fluidizing gas exhaust pipe and not closed. Each independent exhaust pipe has evenly distributed flow equalization holes. The housing 64 has windows 68 aligned with each independent exhaust pipe. Each independent exhaust pipe 62 is fitted with a sleeve that can be extended along... The independent exhaust pipe 62 has a sliding hollow sleeve 65. An elastic body 66 or magnetic body is provided inside the outer shell or outside the independent exhaust pipe to apply pressure or tension to the sleeve 65. This pressure or tension is directed along the axial direction of the independent exhaust pipe 62 towards the fluidizing gas exhaust pipe 61. Through holes 67 are evenly distributed on the sleeve 65. The length of the window 68 along the axial direction of the independent exhaust pipe is less than that of the sleeve 65 and the independent exhaust pipe 62. The width of the window 68 is not greater than the diameter of the sleeve 65. The length of the sleeve 65 is less than the length from the beginning of its corresponding independent exhaust pipe 62 along the axial direction of the independent exhaust pipe. The shortest distance of the shell 64, the length of the sleeve 65 is greater than the length of the independent exhaust pipe 62 inside the sleeve 65, and the end of the sleeve 65 near the end of the independent exhaust pipe is closed. When air is supplied to the independent exhaust pipe, causing the sleeve to overcome pressure or tension and move axially away from the fluidizing gas exhaust pipe until it approaches the end of the independent exhaust pipe, the sleeve blocks the flow equalization hole of the independent exhaust pipe inside the sleeve, and the gas is discharged into the reaction chamber through the independent exhaust pipe. When air supply to the independent exhaust pipe is stopped or the gas pressure is lower than the threshold, the sleeve moves axially along the independent exhaust pipe under the pressure or tension. Approaching the fluidizing gas exhaust pipe and near the beginning of the independent exhaust pipe, the through holes on the sleeve are staggered one-to-one with the flow equalization holes of the independent exhaust pipe. Gas stops flowing into the reaction chamber from the independent exhaust pipe, and the powder in the reaction chamber stops fluidizing and falls onto the surface of the valve device. The sleeve and window can effectively intercept powder from entering the independent exhaust pipe or the fluidizing gas exhaust pipe, which would block the flow equalization holes and affect the powder fluidization and coating effect, or cause powder with saturated surface sites to re-enter the reaction chamber. However, the introduction of reaction gas prevents the powder from reacting with the reaction gas, resulting in the waste of reaction gas.

Furthermore, in each ALD growth cycle unit 3, the outlet of the feed outlet pipe 14 of the first reactor 1 is connected to the inlet of the feed inlet pipe 13 of the second reactor 2. The powder undergoes separate reactions with various precursor gases during the AlD coating reaction, not within a single reaction chamber. The reaction gas exhaust valves 16 of the two reactor inlet pipes 15 in each ALD growth cycle unit 3 are respectively connected to the independent inlet pipes attached to the common reaction gas inlet pipe 21a and the common reaction gas inlet pipe 21b. The common reaction gas inlet pipe 21a of the first reactor 1 is supplied with gas from the first reaction gas source 22a, and the common reaction gas inlet pipe 21b of the second reactor 2 is supplied with gas from the second reaction gas source 22b. The common inlet pipe 20 for inert carrier gas is supplied with gas from the inert carrier gas source 23.

Specifically, multiple ALD growth cycle units 3 are connected in series via pipelines. The inlet of the feed inlet pipe 13 of the first reactor of the first ALD growth cycle unit 3 is connected to the feed tank 24. Starting from the first ALD growth cycle unit 3, the outlet of the feed outlet pipe 14 of the second reactor 2 of the ALD growth cycle unit is connected to the inlet of the feed inlet pipe 13 of the first reactor 1 of the next ALD growth cycle unit 3. The outlet of the feed outlet pipe 14 of the second reactor 2 of the last ALD growth cycle unit 3 is connected to the discharge tank 19. There are at least two ALD growth cycle units 3. The number of ALD growth cycle units 3 is set according to the number of ALD growth cycles required to form a coating on the powder surface. The number of ALD growth cycle units 3 is equal to the number of ALD growth cycles.

A method for coating powder by continuous atomic layer deposition, using the aforementioned apparatus for coating powder by continuous atomic layer deposition, includes the following steps:

Step 1: Using inert carrier gas, the uncoated powder is transported to the reaction chamber of the first reactor 1 of the ALD growth cycle unit 3. Inert carrier gas is continuously introduced into the reaction chamber 4 of the first reactor 1 to heat and fluidize the powder, so that the powder temperature is maintained within the preset temperature value; the total volume of the powder does not exceed the volume of the cleanroom.

Step 2: Pulse the first reaction gas into the reaction chamber 4 of the first reactor 1 to maintain the pressure in the reaction chamber 4 of the first reactor 1 within the target pressure value, and detect the composition of the tail gas discharged from the reaction chamber of the first reactor 1 until it is determined that the first reaction gas is in excess.

Step 3: If the first reaction gas is in excess, discharge the powder into the purification chamber 5 of the first reactor 1 and fill the purification chamber 5 of the first reactor with inert carrier gas until the exhaust gas discharged from the purification chamber 5 of the first reactor 1 does not contain the first reaction gas and byproducts.

Step 4: Use inert carrier gas to transport the powder in the purification chamber 5 of the first reactor 1 to the reaction chamber 4 of the second reactor 2. Inert carrier gas is continuously introduced into the reaction chamber 4 of the second reactor to heat and fluidize the powder, so that the powder temperature is maintained within the preset temperature value.

Step 5: Pulse the second reaction gas into the reaction chamber 4 of the second reactor 2 to maintain the pressure in the reaction chamber 4 of the second reactor 2 within the target pressure value, and detect the composition of the tail gas discharged from the reaction chamber 4 of the second reactor 2 until it is determined that the second reaction gas is in excess.

Step 6: When it is determined that the second reaction gas is in excess, the powder is discharged into the purification chamber of the second reactor, and inert carrier gas is introduced into the purification chamber 5 of the second reactor until the tail gas discharged from the purification chamber 5 of the second reactor 2 does not contain the second reaction gas and by-products, that is, one ALD growth cycle is completed on the powder surface.

Step 7: Repeat steps 1 to 6 in the next ALD growth cycle unit 3 to complete multiple ALD growth cycles on the powder surface coated in the upstream step until the coating on the powder surface reaches the target thickness.

Step 8: Use inert carrier gas to transport the coated powder to the feeding tank 19 for cooling.

Furthermore, the excess of the first or second reaction gas in steps 2 and 5 is determined by the following steps:

The concentration C1 of the first reaction gas/second reaction gas in the exhaust gas and the concentration C2 of the by-products generated by the reaction of the first reaction gas/second reaction gas with the powder are detected.

The excess of the first or second reaction gas is determined based on whether C2 and C1 meet the discrimination criteria. Specifically, the discrimination criteria for determining the excess of the first or second reaction gas include: C1 is not less than the first threshold, but C2 is not greater than the second threshold.

Furthermore, if an ALD growth cycle requires the alternating introduction of three reactive gases, for example, when coating _Li3PO4 on the powder _surface , the first reactive gas, lithium tert-butoxide, needs to be introduced into the reaction chamber first, followed by the introduction of an inert gas to replace the lithium tert-butoxide, then the second reactive gas, water vapor, followed by the introduction of an inert gas to replace the water vapor, then the third reactive gas, trimethyl phosphate, followed by the introduction of an inert gas to replace the trimethyl phosphate, and finally the introduction of the second reactive gas, water vapor, to complete one ALD growth cycle. As shown in Figure 2, each ALD growth cycle unit 3 includes two sets of reactors 1 and 2 connected in series alternately in the order of first reactor 1 to second reactor 2. The outlet of the feed outlet pipe 14 of the first reactor 1 in each ALD growth cycle unit 3 is connected to the inlet of the feed inlet pipe 13 of the second reactor 2, and the outlet of the feed outlet pipe 14 of the first second reactor 2 in each ALD growth cycle unit 3 is connected to the inlet of the feed inlet pipe 13 of the second first reactor 1.

In each ALD growth cycle unit 3, the reaction gas exhaust valve 16 of the inlet pipe 15 of the first reactor 1 is connected to an independent inlet pipe attached to the common reaction gas inlet pipe 21a; the reaction gas exhaust valve 16 of the inlet pipe 15 of the second reactor 1 is connected to an independent inlet pipe attached to the common reaction gas inlet pipe 21c; the reaction gas exhaust valve 16 of the inlet pipe 15 of the first and second reactors 2 is connected to an independent inlet pipe attached to the common reaction gas inlet pipe 21b; and the inlet pipes 15 of all reactors are also connected to an independent inlet pipe attached to the common inert carrier gas inlet pipe 20 via an inert gas exhaust valve 17. The common inlet pipe 21a of the first reactor 1 is supplied with gas from the first gas source 22a, the common inlet pipe 21b of the two second reactors 2 is supplied with gas from the second gas source 22b, the common inlet pipe 21c of the second reactor 1 is supplied with gas from the third gas source 22c, and the common inlet pipe 20 of the inert carrier gas is supplied with gas from the inert carrier gas source 23.

Multiple ALD growth cycle units 3 are connected in series via pipelines. The inlet of the feed inlet pipe 13 of the first reactor of the first ALD growth cycle unit 3 is connected to the feed tank 24. Starting from the first ALD growth cycle unit 3, the outlet of the feed outlet pipe 14 of the second reactor 2 of the ALD growth cycle unit is connected to the inlet of the feed inlet pipe 13 of the first reactor 1 of the next ALD growth cycle unit 3. The outlet of the feed outlet pipe 14 of the second reactor 2 of the last ALD growth cycle unit 3 is connected to the discharge tank 19. The number of ALD growth cycle units 3 is equal to the number of ALD growth cycles, and there are at least two ALD growth cycle units 3.

Preferably, the disc plate 6 is also provided with an exhaust port on the side facing the clean room 5. The exhaust port is connected in sequence to the inert carrier gas exhaust valve 18 and the independent intake pipe attached to the inert carrier gas common intake pipe 20 through another fluidizing gas exhaust pipe inside the disc plate 6.

A method for coating powder by continuous atomic layer deposition, using the aforementioned apparatus for coating powder by continuous atomic layer deposition, includes the following steps:

Step 1: Using inert carrier gas, the uncoated powder is transported to the reaction chamber of the first reactor 1 of the ALD growth cycle unit 3. Inert carrier gas is continuously introduced into the reaction chamber 4 of the first reactor 1 to heat the fluidized powder and keep the powder temperature within the preset temperature value.

Step 2: Pulse the first reaction gas into the reaction chamber 4 of the first reactor 1 to maintain the pressure in the reaction chamber 4 of the first reactor 1 within the target pressure value, and detect the composition of the tail gas discharged from the reaction chamber of the first reactor 1 until it is determined that the first reaction gas is in excess.

Step 3: When it is determined that the first reaction gas is in excess, the powder is discharged into the purification chamber 5 of the first reactor 1, and inert carrier gas is introduced into the purification chamber 5 of the first reactor until the exhaust gas discharged from the purification chamber 5 of the first reactor 1 does not contain the first reaction gas and by-products.

Step 4: Using inert carrier gas, the powder in the purification chamber 5 of the first reactor 1 is transported to the reaction chamber 4 of the first reactor 2. Inert carrier gas is continuously introduced into the reaction chamber 4 of the first reactor to heat and fluidize the powder, so that the powder temperature is maintained within the preset temperature value.

Step 5: Pulse the second reaction gas into the reaction chamber 4 of the first second reactor 2, keep the pressure in the reaction chamber 4 of the first second reactor 2 within the target pressure value, and detect the composition of the exhaust gas discharged from the reaction chamber 4 of the first second reactor 2 until it is determined that the second reaction gas is in excess.

Step 6: If the second reaction gas is in excess, discharge the powder into the purification chamber of the first second reactor and fill the purification chamber 5 of the first second reactor with inert carrier gas until the exhaust gas discharged from the purification chamber 5 of the first second reactor does not contain the second reaction gas and byproducts.

Step 7: Use inert carrier gas to transport the powder in the purification chamber 5 of the first second reactor 2 to the reaction chamber 4 of the second first reactor 1. Inert carrier gas is continuously introduced into the reaction chamber 4 of the second first reactor to heat and fluidize the powder, so that the powder temperature is maintained within the preset temperature value.

Step 8: Pulse the third reaction gas into the reaction chamber 4 of the second first reactor 1, keep the pressure in the reaction chamber 4 of the second first reactor 1 within the target pressure value, and detect the composition of the tail gas discharged from the reaction chamber 4 of the second first reactor 1 until it is determined that the third reaction gas is in excess.

Step 9: If the third reaction gas is in excess, discharge the powder into the purification chamber of the second first reactor and fill the purification chamber 5 of the second first reactor with inert carrier gas until the exhaust gas discharged from the purification chamber 5 of the second first reactor does not contain the third reaction gas and byproducts.

Step 10: Using inert carrier gas, the powder in the purification chamber 5 of the second first reactor 1 is transported to the reaction chamber 4 of the second second reactor 2. Inert carrier gas is continuously introduced into the reaction chamber 4 of the second second reactor to heat and fluidize the powder, so that the powder temperature is maintained within the preset temperature value.

Step 11: Pulse the second reaction gas into the reaction chamber 4 of the second reactor 2, keep the pressure in the reaction chamber 4 of the second reactor 2 within the target pressure value, and detect the composition of the exhaust gas discharged from the reaction chamber 4 of the second reactor 2 until it is determined that the second reaction gas is in excess.

Step 12: When it is determined that the second reaction gas is in excess, the powder is discharged into the purification chamber of the second reactor and inert carrier gas is introduced into the purification chamber 5 of the second reactor until the exhaust gas discharged from the purification chamber 5 of the second reactor 1 does not contain the second reaction gas and by-products, that is, one ALD growth cycle is completed on the powder surface.

Step 13: Repeat steps 1 to 12 in the next ALD growth cycle unit 3 to complete multiple ALD growth cycles on the powder surface coated in the upstream step until the coating on the powder surface reaches the target thickness.

Step 14: Use inert carrier gas to transport the coated powder to the feeding tank 19 for cooling.

Furthermore, the following steps are used to determine whether the first or third reaction gas is in excess in steps 2 and 8, or the second reaction gas is in excess in steps 5 and 11:

The concentrations C1 of the first/second/third reactant gas in the exhaust gas and the concentrations C2 of the byproducts generated by the reaction of the first/second/third reactant gas with the powder are detected.

The excess of the first reaction gas, the second reaction gas, or/and the third reaction gas is determined based on whether C2 and C1 meet the discrimination criteria. Specifically, the discrimination criteria for determining the excess of the first reaction gas, the second reaction gas, or/and the third reaction gas include: C1 is not less than the first threshold, but C2 is not greater than the second threshold.

Example 1

The powder coating method using the continuous atomic layer deposition powder coating apparatus of the present invention can achieve multilayer aluminum oxide coating on graphite powder. The specific operation steps are as follows:

Step 1: Use an inert carrier gas to transport graphite powder to the reaction chamber of the first reactor 1 of the ALD growth cycle unit 3. Inert carrier gas such as nitrogen or hydrogen is continuously introduced into the reaction chamber 4 of the first reactor 1 to heat the fluidized powder and make the powder temperature reach the required 180°C for coating.

Step 2: In the reaction chamber 4 of the first reactor 1, inert carrier gas is continuously injected into the powder through the flow equalization hole of the butterfly plate 6 to fluidize the powder. At the same time, the first reaction gas TMA (the full name of TMA is trimethylaluminum) is pulsed for 0.1 seconds at a time interval of 5 seconds. The tail gas pipe in the reaction chamber 4 of the first reactor 1 is evacuated at the same time to keep the pressure in the reaction chamber 4 of the first reactor 1 within the target pressure value. The components of the tail gas discharged from the reaction chamber of the first reactor 1 are detected by differential electrochemical mass spectrometry.

Step 3: When the concentration of TMA detected in the exhaust gas reaches the preset threshold C1 and the byproduct methane is not greater than the preset threshold C2, it indicates that methane is no longer produced as TMA increases, all oxygen-containing functional group sites on the powder surface have reacted with TMA, the powder surface sites are saturated into a monolayer, and TMA is in excess. Stop the gas supply to the reaction chamber of the first reactor 1 and wait for the powder to settle. At this time, discharge the powder into the purification chamber 5 of the first reactor 1 and fill the purification chamber 5 of the first reactor with inert carrier gas such as nitrogen or hydrogen. At the same time, evacuate the exhaust pipe in the purification chamber 5 of the first reactor 1 until the exhaust gas discharged from the purification chamber 5 of the first reactor 1 does not contain TMA and byproducts.

Step 4: Use an inert carrier gas to transport the powder in the purification chamber of the first reactor to the reaction chamber 4 of the second reactor 2. In the reaction chamber 4 of the second reactor, inert carrier gas such as nitrogen or hydrogen is continuously introduced to heat the fluidized powder and make the powder temperature reach the required 180°C for coating.

Step 5: In the reaction chamber 4 of the second reactor 2, inert carrier gas is continuously sprayed into the powder through the flow equalization hole of the butterfly plate 6 to fluidize the powder. At the same time, water vapor is pulsed into the powder for 0.1 seconds at 5-second intervals. The tail gas pipe in the reaction chamber 4 of the second reactor 2 is simultaneously evacuated to maintain the pressure in the reaction chamber 4 of the second reactor 2 within the target pressure value. The composition of the tail gas discharged from the reaction chamber 4 of the second reactor 2 is detected. Trimethylaluminum reacts with water vapor at high temperature to produce aluminum oxide and methane.

Step 6: When the water vapor concentration in the exhaust gas reaches the preset threshold C1 and the methane concentration does not exceed the preset threshold C2, stop the gas supply to the reaction chamber of the second reactor 2. After the powder settles, discharge the powder into the purification chamber of the second reactor. Inert carrier gas is introduced into the purification chamber 5 of the second reactor. At the same time, the exhaust gas pipe in the purification chamber of the second reactor 2 is evacuated until the exhaust gas discharged from the purification chamber 5 of the second reactor 2 does not contain water vapor and by-product methane, that is, the coating of aluminum oxide is completed on the powder surface.

Step 7: Repeat steps 1 to 6 in the next ALD growth cycle unit 3 to complete multiple ALD growth cycles on the powder surface coated in the upstream step until the coating on the powder surface reaches the target thickness.

Step 8: Use inert carrier gas to transport the coated powder to the feeding tank 19 for cooling.

Example 2

The continuous atomic layer deposition powder coating apparatus and method of the present invention can achieve the deposition of _{multiple Li3PO4} on graphite powder. The specific operation steps are as follows:

Step 1: Use an inert carrier gas to transport graphite powder to the reaction chamber of the first reactor 1 of the ALD growth cycle unit 3. In the reaction chamber 4 of the first reactor 1, inert carrier gas such as nitrogen or hydrogen is continuously introduced to heat the fluidized powder and make the powder temperature reach the required coating temperature of 180°C.

Step 2: In the reaction chamber 4 of the first reactor 1, inert carrier gas is continuously sprayed into the powder through the flow equalization hole of the butterfly plate 6 to fluidize the powder. At the same time, lithium tert-butoxide, the first reaction gas, is pulsed into the powder for 0.1 seconds at 5-second intervals. The tail gas pipe in the reaction chamber 4 of the first reactor is simultaneously evacuated to maintain the pressure in the reaction chamber 4 of the first reactor 1 within the target pressure value. The composition of the tail gas discharged from the reaction chamber of the first reactor 1 is detected until it is determined that the first reaction gas is in excess.

Step 3: When the concentration of lithium tert-butoxide detected in the exhaust gas reaches the preset threshold C1 and the byproduct methane is not greater than the preset threshold C2, it indicates that methane is no longer produced as lithium tert-butoxide increases, all oxygen-containing functional group sites on the powder surface have reacted with lithium tert-butoxide, the powder surface sites are saturated into a monolayer, and lithium tert-butoxide is in excess. Stop the gas supply to the reaction chamber of the first reactor 1 and wait for the powder to settle. At this time, discharge the powder into the purification chamber 5 of the first reactor 1 and fill the purification chamber 5 of the first reactor with inert carrier gas. At the same time, evacuate the exhaust pipe in the purification chamber of the first reactor until the exhaust gas discharged from the purification chamber 5 of the first reactor 1 does not contain lithium tert-butoxide and methane.

Step 4: Using inert carrier gas, the powder in the purification chamber 5 of the first reactor 1 is transported to the reaction chamber 4 of the first reactor 2. Inert carrier gas is continuously introduced into the reaction chamber 4 of the first reactor to heat and fluidize the powder, so that the powder temperature reaches the required 180°C for coating.

Step 5: In the reaction chamber 4 of the first second reactor 2, inert carrier gas is continuously sprayed into the powder through the flow equalization hole of the butterfly plate 6 to fluidize the powder. At the same time, water vapor, the second reaction gas, is pulsed into the powder for 0.1 seconds at 5-second intervals. The tail gas pipe in the reaction chamber of the first second reactor 2 is simultaneously evacuated to maintain the pressure in the reaction chamber 4 of the first second reactor 2 within the target pressure value. The composition of the tail gas discharged from the reaction chamber 4 of the first second reactor 2 is detected until it is determined that the second reaction gas is in excess. After lithium tert-butoxide reacts with water vapor at high temperature, lithium oxide and methane are generated.

Step 6: When the water vapor concentration in the exhaust gas reaches the preset threshold C1 and the methane concentration does not exceed the preset threshold C2, stop the gas supply to the reaction chamber of the first second reactor 2. After the powder settles, discharge the powder into the purification chamber of the first second reactor 5. Inert carrier gas is introduced into the purification chamber 5 of the first second reactor. At the same time, the exhaust gas pipe in the purification chamber of the first second reactor is evacuated until the exhaust gas discharged from the purification chamber 5 of the first second reactor 2 does not contain the second reaction gas and byproducts.

Step 7: Use inert carrier gas to transport the powder in the purification chamber 5 of the first second reactor 2 to the reaction chamber 4 of the second first reactor 1. Inert carrier gas is continuously introduced into the reaction chamber 4 of the second first reactor to heat and fluidize the powder, so that the powder temperature reaches the required 180°C for coating.

Step 8: In the reaction chamber 4 of the second first reactor 1, inert carrier gas is continuously sprayed into the powder through the flow equalization hole of the butterfly plate 6 to fluidize the powder. At the same time, the third reaction gas trimethyl phosphate is pulsed into the powder for 0.1 seconds at 5-second intervals. The tail gas pipe in the reaction chamber of the second first reactor is simultaneously evacuated to maintain the pressure in the reaction chamber 4 of the second first reactor 1 within the target pressure value. The composition of the tail gas discharged from the reaction chamber 4 of the second first reactor 1 is detected until it is determined that the third reaction gas is in excess.

Step 9: When the concentration of trimethyl phosphate detected in the exhaust gas reaches the preset threshold C1 and the byproduct methane is not greater than the preset threshold C2, it indicates that methane is no longer produced as trimethyl phosphate increases, all oxygen-containing functional group sites on the powder surface have reacted with trimethyl phosphate, the powder surface sites are saturated into a monolayer, and trimethyl phosphate is in excess. Stop the gas supply to the reaction chamber of the second first reactor 1 and wait for the powder to settle. At this time, discharge the powder into the purification chamber of the second first reactor 5 and fill the purification chamber 5 of the second first reactor with inert carrier gas. At the same time, evacuate the exhaust pipe in the purification chamber of the second first reactor until the exhaust gas discharged from the purification chamber 5 of the second first reactor 1 does not contain trimethyl phosphate and methane.

Step 10: Using inert carrier gas, the powder in the purification chamber 5 of the second first reactor 1 is transported to the reaction chamber 4 of the second second reactor 2. Inert carrier gas is continuously introduced into the reaction chamber 4 of the second second reactor to heat and fluidize the powder, so that the powder temperature is maintained within the preset temperature value.

Step 11: In the reaction chamber 4 of the second reactor 2, inert carrier gas is continuously sprayed into the powder through the flow equalization hole of the butterfly plate 6 to fluidize the powder. At the same time, water vapor, the second reaction gas, is pulsed into the powder for 0.1 seconds at 5-second intervals. The tail gas pipe in the reaction chamber of the second reactor 2 is evacuated at the same time to keep the pressure in the reaction chamber 4 of the second reactor 2 within the target pressure value. The composition of the tail gas discharged from the reaction chamber 4 of the second reactor 2 is detected until it is determined that the second reaction gas is in excess. After lithium oxide reacts with trimethyl phosphate and water vapor at high temperature, lithium phosphate and methane are generated.

Step 12: When the water vapor in the exhaust gas reaches the preset threshold C1 and the methane concentration does not exceed the preset threshold C2, stop the gas supply to the reaction chamber of the second reactor 2. After the powder settles, discharge the powder into the purification chamber of the second reactor 2. Inert carrier gas is introduced into the purification chamber 5 of the second reactor 2. At the same time, the exhaust gas pipe in the purification chamber of the second reactor 1 is evacuated until the exhaust gas discharged from the purification chamber 5 of the second reactor 1 does not contain the second reaction gas and by-products, that is, one ALD growth cycle is completed on the powder surface.

Step 13: Repeat steps 1 to 13 in the next ALD growth cycle unit 3 to complete multiple ALD growth cycles on the powder surface coated in the upstream step until the coating on the powder surface reaches the target thickness.

Step 14: Use inert carrier gas to transport the coated powder to the feeding tank 19 for cooling.

The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims (12)

A reactor, characterized in that it comprises: a reaction chamber and a purification chamber, the purification chamber being located below the reaction chamber, a valve device being provided between the reaction chamber and the purification chamber, the valve device being operable between an open position and a closed position, the valve device having a disc, the purification chamber being isolated from the reaction chamber by the disc when the valve device is in the closed position, the disc being constructed to include flow equalization holes evenly distributed on the side of the disc facing the reaction chamber, and a fluidizing gas exhaust pipe located inside the disc and communicating with all the flow equalization holes; The reaction chamber is equipped with a pressure detection device and a temperature sensor. The reaction chamber is equipped with a heating device outside the reaction chamber. The reaction chamber is connected to a differential electrochemical mass spectrometer and a vacuum pump in sequence through a tail gas exhaust pipe. A filter to prevent particle inhalation is provided at the inlet of the tail gas exhaust pipe. The reaction chamber is also connected to the outlet of the feed inlet pipe. The fluidizing gas exhaust pipe is connected to the inlet pipe. The inlet pipe is connected to the common inlet pipe of the reaction gas and the independent inlet pipe attached to the common inlet pipe of the inert carrier gas through a reaction gas exhaust valve and an inert carrier gas exhaust valve, respectively. The bottom of the purification chamber is connected to the inlet of the material outlet pipe. The purification chamber is also connected to an independent inlet pipe attached to the common inlet pipe of the inert carrier gas through an inert carrier gas exhaust valve. The purification chamber is also connected to the differential electrochemical mass spectrometer and the vacuum pump in sequence through the tail gas pipe. The disc plate includes a shell, and a fluidizing gas exhaust pipe is arranged along the central axis of the disc plate inside the shell. Multiple independent exhaust pipes are attached to the fluidizing gas exhaust pipe. The beginning of the independent exhaust pipe is connected to the fluidizing gas exhaust pipe, and the end of the independent exhaust pipe is away from the fluidizing gas exhaust pipe. Flow equalization holes are evenly arranged on each independent exhaust pipe. The disc also includes an opening and closing device that operates in both blocking and unblocking the flow equalization orifice. The opening and closing device is disposed within the housing as follows: The independent exhaust pipe is closed at the end, and the flow equalization hole extends from the inside of the independent exhaust pipe to the surface of the outer shell. Each independent exhaust pipe is fitted with a hollow sleeve that can slide along the independent exhaust pipe, and an elastic body or magnetic body that can apply pressure or tension to the sleeve. The pressure or tension is directed along the axial direction of the independent exhaust pipe towards the fluidizing gas exhaust pipe. The sleeve is uniformly provided with through holes, and the end of the sleeve near the end of the independent exhaust pipe is closed. The length of the independent exhaust pipe is greater than the length of the sleeve inside the independent exhaust pipe. When air is supplied to the independent exhaust pipe, causing the sleeve to overcome the pressure or tension and move axially away from the fluidizing gas exhaust pipe to near the end of the independent exhaust pipe, the through hole on the sleeve is aligned one-to-one with the flow equalization hole of the independent exhaust pipe. When air supply to the independent exhaust pipe is stopped or the gas pressure is lower than the threshold, the sleeve moves axially towards the fluidizing gas exhaust pipe to near the beginning of the independent exhaust pipe under the pressure or tension, and the sleeve blocks the flow equalization hole of the independent exhaust pipe. The reactor according to claim 1 is characterized in that the disc plate is provided with an exhaust port on the side facing the purification chamber, and the exhaust port is connected in sequence to an inert carrier gas exhaust valve and an independent air inlet pipe attached to the common air inlet pipe of the inert carrier gas through another fluidizing gas exhaust pipe inside the disc plate. The reactor according to claim 1 is characterized in that a stirring device is provided in the reaction chamber. According to claim 1, the reactor is characterized in that the opening and closing device can also be arranged inside the outer shell in another manner, the end of the independent exhaust pipe is not closed, the outer shell is provided with windows aligned with each independent exhaust pipe, each independent exhaust pipe is fitted with a hollow sleeve that can slide along the independent exhaust pipe, an elastic body or magnetic body that can apply pressure or tension to the sleeve is provided inside the outer shell or outside the independent exhaust pipe, the pressure or tension is directed along the axial direction of the independent exhaust pipe towards the fluidizing gas exhaust pipe, through holes are uniformly arranged on the sleeve, the length of the window along the axial direction of the independent exhaust pipe is less than that of the sleeve and the independent exhaust pipe, the width of the window is not greater than the diameter of the sleeve, and the length of the sleeve is less than The shortest distance from the beginning of the independent exhaust pipe inside the sleeve along the axial direction of the independent exhaust pipe to the shell. The length of the sleeve is greater than the length of the independent exhaust pipe inside the sleeve. The end of the sleeve near the end of the independent exhaust pipe is closed. When air is supplied to the independent exhaust pipe, causing the sleeve to overcome pressure or tension and move away from the fluidizing gas exhaust pipe along the axial direction of the independent exhaust pipe until it approaches the end of the independent exhaust pipe, the through hole on the sleeve is aligned one-to-one with the flow equalization hole of the independent exhaust pipe. When air supply to the independent exhaust pipe is stopped or the gas pressure is lower than the threshold, the sleeve moves closer to the fluidizing gas exhaust pipe along the axial direction of the independent exhaust pipe under the pressure or tension until it approaches the beginning of the independent exhaust pipe, and the sleeve blocks the flow equalization hole of the independent exhaust pipe. An apparatus for continuous atomic layer deposition (ALD) coating powder, characterized in that it includes a reactor as described in any one of claims 1 to 4, wherein every two reactors form an ALD growth cycle unit, the outlet of the feed outlet pipe of the first reactor is connected to the inlet of the feed inlet pipe of the second reactor, the common inlet pipe of the first reactor is supplied with gas from a first reaction gas source, the common inlet pipe of the second reactor is supplied with gas from a second reaction gas source, and the common inlet pipe of the inert carrier gas is supplied with gas from an inert carrier gas source. Multiple ALD growth cycle units are connected in series. The inlet of the feed inlet pipe of the first reactor in the first ALD growth cycle unit is connected to the feed tank. Starting from the first ALD growth cycle unit, the outlet of the feed outlet pipe of the second reactor in the ALD growth cycle unit is connected to the inlet of the feed inlet pipe of the first reactor in the next ALD growth cycle unit. The outlet of the feed outlet pipe of the second reactor in the last ALD growth cycle unit is connected to the discharge tank. A method for coating powder by continuous atomic layer deposition, characterized in that it uses the apparatus for coating powder by continuous atomic layer deposition as described in claim 5, and includes the following steps: S1. Using inert carrier gas, the uncoated powder is transported to the reaction chamber of the first reactor in the ALD growth cycle unit. Inert carrier gas is continuously introduced into the reaction chamber of the first reactor to heat the fluidized powder and keep the powder temperature within the preset temperature value. S2. In the reaction chamber of the first reactor, the powder is pulsed with the first reaction gas to maintain the pressure in the reaction chamber of the first reactor within the target pressure value. The composition of the tail gas discharged from the reaction chamber of the first reactor is detected until it is determined that the first reaction gas is in excess. S3. If it is determined that the first reaction gas is in excess, discharge the powder into the purification chamber of the first reactor and fill the purification chamber of the first reactor with inert carrier gas until the exhaust gas discharged from the purification chamber of the first reactor does not contain the first reaction gas and by-products. S4. The powder in the purification chamber of the first reactor is transported to the reaction chamber of the second reactor using inert carrier gas. Inert carrier gas is continuously introduced into the reaction chamber of the second reactor to heat and fluidize the powder, so that the powder temperature is maintained within the preset temperature value. S5. In the reaction chamber of the second reactor, pulse the second reaction gas into the powder, keep the pressure in the reaction chamber of the second reactor within the target pressure value, and detect the composition of the tail gas discharged from the reaction chamber of the second reactor until it is determined that the second reaction gas is in excess. S6. When it is determined that the second reaction gas is in excess, the powder is discharged into the purification chamber of the second reactor, and inert carrier gas is introduced into the purification chamber of the second reactor until the exhaust gas discharged from the purification chamber of the second reactor does not contain the second reaction gas and by-products, that is, one ALD growth cycle is completed on the powder surface. S7. Repeat steps S1 to S6 in the next ALD growth cycle unit to complete multiple ALD growth cycles on the powder surface partially coated in the upstream step until the coating on the powder surface reaches the target thickness. S8. The coated powder is transported to a feeding tank for cooling using an inert carrier gas; the powder includes uncoated powder or powder partially coated from an upstream step in the coating process. The method for continuous atomic layer deposition coating powder according to claim 6 is characterized in that the excess of the first reactant gas or the second reactant gas is determined by the following steps: The concentration C1 of the first reaction gas/second reaction gas in the exhaust gas and the concentration C2 of the by-products generated by the reaction of the first reaction gas/second reaction gas with the powder are detected. The excess of either the first or second reaction gas is determined based on whether C2 and C1 meet the discrimination criteria. The method for continuous atomic layer deposition coating powder according to claim 7, characterized in that the criteria for determining whether the first reactant gas or the second reactant gas is in excess include: C1 is not less than the first threshold, but C2 is not greater than the second threshold. An apparatus for continuous atomic layer deposition (ALD) coating powder, characterized in that it includes a reactor as described in any one of claims 1 to 4, wherein every four reactors form an ALD growth cycle unit, the outlet of the feed outlet pipe of the first reactor in the first to fourth reactors is connected to the inlet of the feed inlet pipe of the next reactor, the common inlet pipe of the reaction gas of the first reactor is supplied with gas from a first reaction gas source, the common inlet pipe of the reaction gas of the second and fourth reactors is supplied with gas from a second reaction gas source, the common inlet pipe of the reaction gas of the third reactor is supplied with gas from a third reaction gas source, and the common inlet pipe of the inert carrier gas is supplied with gas from an inert carrier gas source. Multiple ALD growth cycle units are connected in series. The inlet of the feed inlet pipe of the first reactor in the first ALD growth cycle unit is connected to the feed tank. Starting from the first ALD growth cycle unit, the outlet of the feed outlet pipe of the fourth reactor in the ALD growth cycle unit is connected to the inlet of the feed inlet pipe of the first reactor in the next ALD growth cycle unit. The outlet of the feed outlet pipe of the fourth reactor in the last ALD growth cycle unit is connected to the discharge tank. A method for coating powder by continuous atomic layer deposition, characterized in that it uses the apparatus for coating powder by continuous atomic layer deposition as described in claim 9, and includes the following steps: F1. The uncoated powder is transported to the reaction chamber of the first reactor in the ALD growth cycle unit using an inert carrier gas. The inert carrier gas is continuously introduced into the reaction chamber of the first reactor to heat the fluidized powder and keep the powder temperature within the preset temperature value. F2. In the reaction chamber of the first reactor, the powder is pulsed with the first reaction gas, and the pressure in the reaction chamber of the first reactor is kept within the target pressure value. The composition of the exhaust gas discharged from the reaction chamber of the first reactor is detected until it is determined that the first reaction gas is in excess. F3. If it is determined that the first reaction gas is in excess, the powder is discharged into the purification chamber of the first reactor, and inert carrier gas is introduced into the purification chamber of the first reactor until the exhaust gas discharged from the purification chamber of the first reactor does not contain the first reaction gas and by-products. F4. The powder in the purification chamber of the first reactor is transported to the reaction chamber of the second reactor using an inert carrier gas. The inert carrier gas is continuously introduced into the reaction chamber of the second reactor to heat and fluidize the powder, so that the powder temperature is maintained within the preset temperature value. F5. In the reaction chamber of the second reactor, pulse the second reaction gas into the powder, keep the pressure in the reaction chamber of the second reactor within the target pressure value, and detect the composition of the tail gas discharged from the reaction chamber of the second reactor until it is determined that the second reaction gas is in excess. F6. If the second reaction gas is found to be in excess, the powder is discharged into the purification chamber of the second reactor, and inert carrier gas is introduced into the purification chamber of the second reactor until the exhaust gas discharged from the purification chamber of the second reactor does not contain the second reaction gas and by-products. F7. The powder in the purification chamber of the second reactor is transported to the reaction chamber of the third reactor using inert carrier gas. Inert carrier gas is continuously introduced into the reaction chamber of the third reactor to heat and fluidize the powder, so that the powder temperature is maintained within the preset temperature value. F8. In the reaction chamber of the third reactor, pulse the third reaction gas into the powder, keep the pressure in the reaction chamber of the third reactor within the target pressure value, and detect the composition of the tail gas discharged from the reaction chamber of the third reactor until it is determined that the third reaction gas is in excess. F9. If the third reaction gas is found to be in excess, the powder is discharged into the purification chamber of the third reactor, and inert carrier gas is introduced into the purification chamber of the third reactor until the exhaust gas discharged from the purification chamber of the third reactor does not contain the third reaction gas and byproducts. F10. The powder in the purification chamber of the third reactor is transported to the reaction chamber of the fourth reactor using inert carrier gas. Inert carrier gas is continuously introduced into the reaction chamber of the fourth reactor to heat the fluidized powder and keep the powder temperature within the preset temperature value. F11. In the reaction chamber of the fourth reactor, the powder is pulsed with the second reaction gas to maintain the pressure in the reaction chamber of the fourth reactor within the target pressure value. The composition of the exhaust gas discharged from the reaction chamber of the fourth reactor is detected until it is determined that the second reaction gas is in excess. F12. When it is determined that the second reaction gas is in excess, the powder is discharged into the purification chamber of the fourth reactor, and inert carrier gas is introduced into the purification chamber of the fourth reactor until the exhaust gas discharged from the purification chamber of the fourth reactor does not contain the second reaction gas and by-products, that is, one ALD growth cycle is completed on the powder surface. F13. Repeat steps F1 to F12 in the next ALD growth cycle unit to complete multiple ALD growth cycles on the powder surface partially coated in the upstream step until the coating on the powder surface reaches the target thickness. F14. The coated powder is transported to a feeding tank for cooling using an inert carrier gas; the powder includes uncoated powder or powder partially coated from upstream steps in the coating process. The method for continuous atomic layer deposition coating powder according to claim 10 is characterized by determining the excess of the first reactant gas, the second reactant gas, or the third reactant gas through the following steps: The concentrations C1 of the first/second/third reactant gas in the exhaust gas and the concentrations C2 of the byproducts generated by the reaction of the first/second/third reactant gas with the powder are detected. The excess of the first, second, or third reaction gas is determined based on whether C2 and C1 meet the discrimination criteria. The method for continuous atomic layer deposition coating powder according to claim 11 is characterized in that the criteria for determining whether the first reactant gas, the second reactant gas, or the third reactant gas is in excess include: C1 is not less than the first threshold, but C2 is not greater than the second threshold.