CN105648422A - Gaseous phase atomic layer deposition device for electrode powder material coating and application - Google Patents

Abstract

The invention discloses a gaseous phase atomic layer deposition device for electrode powder material coating and a method for electrode powder material coating. The gaseous phase atomic layer deposition device comprises a vacuum reaction cavity and a monitoring system. A stirring device is arranged in the vacuum reaction cavity. The stirring device is in electric connection or in signal connection with the monitoring system and is controlled to operate through the monitoring system. According to the gaseous phase atomic layer deposition device, the stirring device is added in the reaction cavity, an electrode powder material is fully dispersed through the stirring device, aggregation of the electrode powder material is reduced, precursor adsorption and reaction are facilitated, the coating uniformity and efficiency are improved, and a foundation for mass production of the high-quality battery electrode powder coating material is laid.

Description

A gas phase atomic layer deposition device and application for electrode powder material coating

technical field

The present application relates to the field of electrode material processing for lithium-ion batteries, in particular to a gas-phase atomic layer deposition device for covering electrode powder materials of lithium-ion batteries and its application.

Background technique

Lithium-ion batteries have been widely used in small mobile digital electronic products, including mobile phones, cameras, and notebook computers, due to their excellent performance such as high specific capacity, high cycle performance, high energy density, and high power density. With the rapid development of lithium-ion battery technology, lithium-ion batteries are also recognized as the most promising power storage batteries for electric vehicles. The performance of electrode powder materials for lithium-ion batteries largely determines the performance of lithium-ion batteries. Studies have shown that the performance of lithium-ion batteries can be effectively improved by coating and modifying electrode powder materials.

The existing coating methods of electrode powder materials for lithium-ion batteries mainly include solid-phase method, liquid-phase method and gas-phase method. Among them, atomic layer deposition technology is a special chemical vapor deposition technology, and the prepared film has the advantages of uniformity, compactness, precise and controllable thickness, and high conformality. The use of atomic layer deposition technology to coat electrode powder materials refers to obtaining a very uniform nanometer-thick film layer on the surface of electrode powder materials through self-limiting chemical adsorption reactions.

However, the electrode powder materials of lithium-ion batteries have a large specific surface area and high specific surface energy, which leads to serious particle agglomeration, affects the uniformity and efficiency of coating, and then affects the coating modified electrode powder. The properties of materials and the performance of lithium-ion batteries. This is especially serious when a large amount of powder coating is carried out in industrial production; it seriously restricts the further development of coating modification of lithium ion battery electrode powder materials and large-scale industrial application. Therefore, it is necessary to improve the traditional device for atomic layer deposition on the surface of the substrate to meet the production requirements of coating modification of special powder materials such as lithium-ion battery electrode powder materials.

Contents of the invention

The purpose of this application is to provide an improved vapor phase atomic layer deposition device and its application, which are especially used for electrode powder material coating of lithium ion batteries.

The application adopts the following technical solutions:

One aspect of the present application discloses a vapor phase atomic layer deposition device for electrode powder material coating, including a vacuum reaction chamber and a monitoring system, a stirring device is arranged in the vacuum reaction chamber, and the stirring device is electrically connected to the monitoring system Or signal connection, control the operation of the stirring device through the monitoring system.

The gas-phase atomic layer deposition device of the present application is a device that realizes gas-solid alternating reaction. Specifically, solid particles are placed in the reaction chamber, and then the gas-phase precursor is fed into the gas-phase precursor. The gas-phase precursor is in contact with the solid particles. A device that adsorbs and reacts on the surface of solid particles to form a coating. Because gas-phase precursors are adsorbed and reacted on the surface of solid particles in the form of molecules or atoms, and are coated layer by layer on the surface of solid particles in the form of monoatomic films, it is called gas-phase atomic layer deposition.

It should be noted that the key point of this application is that, based on the existing gas-phase atomic layer deposition device, a stirring device is installed in the vacuum reaction chamber, and the electrode powder material is fully dispersed by the stirring device to reduce the amount of electrode powder material. Agglomeration is conducive to the adsorption and reaction of precursors, so that the vapor phase atomic layer deposition is more uniform, and high-quality electrode coating materials are produced; moreover, the vapor phase atomic layer deposition device of the present application is particularly suitable for the processing of large quantities of electrode powder materials, It can meet the needs of industrialized mass production. In addition, the connection between the stirring device and the monitoring system is mainly for the convenience of real-time monitoring and control of the rotation speed of the stirring device. The key to this application is to add a stirring device. As for others, such as vacuum system, precursor system, heating system, and monitoring system, etc., you can refer to the existing vapor phase atomic layer deposition device, and will not repeat it here.

Therefore, in one implementation of the present application, the vapor phase atomic layer deposition device also includes a vacuum system, a precursor system and a heating system; the vacuum system is used to evacuate the vacuum reaction chamber, and the precursor system is used to pump the vacuum reaction chamber The precursor is provided, the heating system is used to heat the vacuum reaction chamber, and the monitoring system is used to detect the pressure and temperature in the vacuum reaction chamber, and control the opening or closing of the vacuum system, the precursor system and the heating system.

Preferably, the stirring device is at least one of paddle stirring, turbine stirring and frame stirring.

It should be noted that the purpose of the stirring device of the present application is to raise the electrode powder material and make it fully dispersed so as to facilitate the adsorption and reaction of the precursor; therefore, as long as the electrode powder material can be raised, as for The specific structure to be adopted can be determined according to different production conditions. In the preferred solution of the present application, at least one of paddle stirring, turbine stirring and frame stirring is used to realize the stirring function. It can be understood that, when production conditions permit or in some special cases, a structure and method similar to the rotation of a washing machine drum can even be used to raise the electrode powder material, such as the vacuum reaction chamber itself rotating. In this case, the vacuum reaction chamber The structure itself is equivalent to the stirring device of the present application.

Preferably, the vacuum reaction chamber is composed of an upper chamber and a lower chamber, one end of the stirring device is fixed on the top of the upper chamber, and the other end extends into the lower chamber.

Another aspect of the present application discloses the application of the vapor phase atomic layer deposition device of the present application in the surface coating of powder materials.

It should be noted that although the vapor-phase atomic layer deposition device of the present application is designed for the coating of electrode powder materials, the vapor-phase atomic layer deposition device of the present application is not limited to the coating of electrode powder materials. Any particle that needs to be coated can use the vapor phase atomic layer deposition device of the present application.

Another aspect of the application discloses a method for coating electrode powder materials, wherein the electrode powder materials are positive electrode powder materials for lithium-ion batteries or negative electrode powder materials for lithium-ion batteries, and the method uses the gas phase atomic layer of the application The deposition device coats and modifies the electrode powder material.

In a specific implementation of the present application, the method includes the following steps,

(a) loading the electrode powder material to be processed into the vacuum reaction chamber of the vapor phase atomic layer deposition device;

(b) Vacuumize the vacuum reaction chamber to maintain effective isolation between the vacuum reaction chamber and the external air environment;

(c) Use a stirring device to raise the electrode powder material to fully disperse it;

(d) Passing the first gas phase precursor into the vacuum reaction chamber to make it adsorb on the surface of the electrode powder material;

(e) feed carrier gas to remove excess first gas phase precursor in the vacuum reaction chamber;

(f) introducing a second gas-phase precursor into the vacuum reaction chamber to react with the first gas-phase precursor adsorbed on the surface of the electrode powder material to form a coating layer;

(g) feed the carrier gas to remove the redundant second gas phase precursor in the vacuum reaction chamber;

Steps (d) to (g) are repeated until a coating of a defined thickness or structure is obtained.

It should be noted that steps (d) to (g) can actually complete one layer of vapor-phase atomic layer deposition coating, but in order to obtain a thicker coating layer, it is usually necessary to perform multiple depositions, so the steps need to be repeated (d) to (g) until the cladding layer of the desired thickness is obtained; as for how many times it needs to be repeated, it depends on the specific first gas phase precursor and the second gas phase precursor used, and the specific required The thickness of the coating layer is not specifically limited here.

It should also be noted that, using the vapor phase atomic layer deposition device and method of the present application, one, two, or even multiple materials can be used to coat the electrode powder materials to form coating layers with different structures, as long as the corresponding The first gas-phase precursor and the second gas-phase precursor are sufficient. In addition, the first gas-phase precursor and the second gas-phase precursor actually assume that the coating layer can be obtained by reacting the two precursors. This is a relatively conventional reaction mode for obtaining the coating layer, so this assumption is made.

It can be understood that if the first gas-phase precursor is adsorbed on the surface of the electrode powder material, and then the coating layer can be formed after some special conditions, of course there is no need to feed the second gas-phase precursor, that is, the step (f ) and (g). Or, if more gas-phase precursors are needed to react to form the cladding layer, for example, a third gas-phase precursor, a fourth gas-phase precursor, or even more precursors are required, correspondingly increase the gas-phase precursor Clean the excess gas-phase precursor with the carrier gas, then pass in another gas-phase precursor, and then clean with the carrier gas, and so on.

Preferably, the stirring speed of the stirring device is 100-1000 revolutions per minute.

It should be noted that the stirring speed is adjusted according to the original particle size and quality of the electrode powder material particles of the lithium-ion battery; if the speed is too low, the accumulated electrode powder material cannot be fully dispersed; if the speed is too high, the electrode powder Due to the effect of centrifugal force, the material particles will move closer to the wall of the reaction chamber, which is contrary to the original intention of electrode powder material dispersion. For this reason, a large number of experiments have confirmed that for electrode powder materials with primary particle size and mass of micron-sized particles, adjusting the stirring speed at 500-1000 rpm can achieve a more ideal powder dispersion effect; Electrode powder materials with nano-sized particles with small diameter and mass, and adjusting the stirring speed at 100-500 rpm can achieve a more ideal powder dispersion effect.

Preferably, in the vacuum reaction chamber, the reaction temperature of the first gas-phase precursor and the second gas-phase precursor is 50-300°C.

It should be noted that the reaction temperature of the first gas-phase precursor and the second gas-phase precursor is actually the temperature in the vacuum reaction chamber, which is controlled by the monitoring system to heat the heating system to keep it at the required temperature ; Wherein, the specific reaction temperature is determined according to the specific precursor used and its required reaction temperature, and is not specifically limited here; generally speaking, according to the coating material used for the electrode powder material, The reaction temperature is all between 50-300°C.

Preferably, the carrier gas is an inert gas. More preferably, the carrier gas is nitrogen or argon.

Preferably, the temperature of the carrier gas is 50-300°C.

It should be noted that one of the main purposes of the carrier gas is to clean the first gas-phase precursor and the second gas-phase precursor. However, in order to avoid affecting the temperature in the vacuum reaction chamber, a temperature of 50- 300°C carrier gas; it can be understood that the specific carrier gas temperature is consistent with the reaction temperature in the vacuum reaction chamber, and is not specifically limited here.

Preferably, the temperature of the first gas-phase precursor and the second gas-phase precursor is 50-200°C.

It should be noted that the higher the melting point of the precursor, the lower its saturated vapor pressure, and the less the amount of precursor that can participate in the reaction obtained under the same conditions; therefore, for common precursors, the temperature is controlled at 50-100 degrees Celsius; For solid precursors with very high melting points, the temperature can reach 200 degrees Celsius. It can be understood that, in order to prevent the precursor from condensing in the delivery pipeline, it is necessary to heat the pipeline so that its temperature is controlled at 50-200 degrees Celsius.

The beneficial effect of this application is:

The gas-phase atomic layer deposition device of the present application is specially designed for the coating and modification of lithium-ion battery electrode powder. A stirring device is added in the reaction chamber, and the stirring device is used to stir the electrode powder material of the lithium-ion battery, and, by adjusting The rotation speed and direction of the stirring device can fully disperse electrode powder materials of different quality and particle size, effectively reduce the degree of powder agglomeration, facilitate the adsorption and reaction of precursors, and improve the coating uniformity and coating efficiency. The industrialized large-scale production of high-quality lithium-ion battery electrode powder coating materials has laid the foundation.

Description of drawings

Fig. 1 is a schematic structural diagram of a vapor phase atomic layer deposition device in an embodiment of the present application;

Fig. 2 is a schematic block diagram of the process flow of the electrode powder material coating method in the embodiment of the present application;

Fig. 3 is a transmission electron microscope image of the electrode powder material before and after coating in the embodiment of the present application, (a) is the scanning result before coating, and (b) is the scanning result after coating.

detailed description

The gas-phase atomic layer deposition device of the present application is especially improved for the coating of lithium-ion battery electrode powder materials. Specifically, a stirring device is installed in the vacuum reaction chamber, and the electrode powder material is raised by the stirring device to make it Dispersion, which facilitates the uniform and effective adsorption of the precursor on the surface of the electrode powder material particles, making the vapor phase atomic layer deposition coating more uniform.

It can be understood that although the gas-phase atomic layer deposition device used for electrode powder material coating of the present application is specially improved for the coating of lithium-ion battery electrode powder materials, the gas-phase atomic layer deposition device is not limited to use It can be used for the coating of lithium-ion battery electrode powder materials, and can also be used in various other situations where a coating layer needs to be formed on the particle surface.

It should be noted that the coating method of the electrode powder material in this application is the situation where two precursors react to form a coating layer; the vapor phase atomic layer deposition device or coating method in this application is not only Limited to two precursors, three or more precursors can also be used in a certain order to realize the preparation of multilayer film structures. Correspondingly, in the coating method, after the second gas phase precursor is cleaned, the third One gas-phase precursor, then the third gas-phase precursor is cleaned with carrier gas, the fourth gas-phase precursor is introduced, carrier gas is cleaned, and so on.

In addition, after the precursor is introduced, pressure-holding adsorption or non-pressure-holding adsorption can be used. Pressure-holding adsorption means that when the precursor is introduced, the vacuum system is turned off to maintain a certain air pressure in the vacuum reaction chamber to facilitate the adsorption of the precursor. After a period of time, turn on the vacuum system to extract the precursor; without pressure-holding adsorption, the vacuum system is turned on when the precursor is introduced, so that the air pressure in the vacuum reaction chamber is always maintained at the initial air pressure. The specific use of pressure-holding adsorption or no-pressure-holding adsorption can be determined according to the difficulty of adsorption of each precursor, and is not specifically limited here.

The present application will be described in further detail below through specific examples. The following examples only further illustrate the present application, and should not be construed as limiting the present application.

Example

The vapor phase atomic layer deposition device used for electrode powder material coating in this example consists of a vacuum reaction chamber, a vacuum system, a precursor system, a heating system, and a monitoring system. Among them, the precursor system is used to input carrier gas and gas phase precursor into the vacuum reaction chamber. The heating system is used to heat the vacuum reaction chamber, precursor container and connecting pipelines. The vacuum system is used to maintain the vacuum of the vacuum reaction chamber, adjust the internal pressure of the vacuum reaction chamber, and discharge residual precursors and by-products in the vacuum reaction chamber. The monitoring system is used to monitor and display the pressure inside the vacuum reaction chamber, the temperature of the reaction area, the outer wall temperature of the vacuum reaction chamber, the temperature of the precursor container, the temperature of the connecting pipeline, etc.; and control the pulse time and flow rate of the precursor in the precursor system , cycle times, carrier gas cleaning time and flow rate, control the switch of heating system and vacuum system.

In this example, the vacuum reaction chamber is shown in Figure 1. The entire vacuum reaction chamber rests on the support frame 15. The vacuum reaction chamber is composed of a lower chamber 1 and an upper chamber 2, and the lower chamber 1 is fixed on the support frame. 15, the upper cavity 2 is connected to the support frame 15 through the guide wheel 14, and the upper cavity 2 can move up and down along the support frame 15 through the guide wheel 14; one end of the stirring device 4 is fixed on the top of the upper cavity 2, through the seal 3 sealing, when the upper cavity 2 and the lower cavity 1 are closed, the other end of the stirring device 4 extends into the lower cavity 1. In addition, the vacuum reaction chamber is also provided with a filling port 5, an air inlet 6, an air outlet 7, a lower chamber hot oil inlet 8, a lower chamber hot oil outlet 9, an upper chamber hot oil inlet 10 and an upper chamber hot oil inlet 10. Hot oil outlet 11.

Wherein, the filling port 5 is arranged on the top of the upper cavity 2 for adding the material of the electrode body. The air inlet 6 is opened at the bottom of the lower cavity 1, and is used to connect the precursor system; in this example, the precursor system includes two parallel precursor delivery branches, respectively providing the first gas phase precursor and the second The precursor raw material of a gas phase precursor, the precursor raw material is passed into the vacuum reaction chamber through the air inlet 6. The air outlet is opened on the top of the upper chamber 2, next to the filling port 5, and is used to connect the vacuum system. The vacuum pump 13 of the vacuum system pumps air through the air outlet 7 to the vacuum reaction chamber to maintain the vacuum of the vacuum reaction chamber. Adjust the internal pressure of the vacuum reaction chamber and the discharge of residual precursors and/or by-products in the vacuum reaction chamber; and, in one implementation of the application, a dust filter is also provided between the vacuum pump 13 and the gas outlet 7 The device 12 is used to filter residual precursors and/or by-products and a small amount of dust brought by the carrier gas from the reaction chamber. The lower chamber hot oil inlet 8 and the lower chamber hot oil outlet 9 are opened on the lower chamber 1, the lower chamber hot oil inlet 8 is opened on the lower side of the lower chamber 1, and the lower chamber hot oil outlet 9 is opened on the lower side of the lower chamber. The upper side of the cavity 1 is used to connect the heating system. The heated hot oil enters through the hot oil inlet 8 of the lower cavity, and then is discharged from the hot oil outlet 9 of the lower cavity. During this process, the heat is transferred to the lower cavity 1, in order to realize the heating of the lower chamber 1. Similarly, the upper chamber hot oil inlet 10 and the upper chamber hot oil outlet 11 opened in the upper chamber 2 are also used to connect the heating system, and the upper chamber 2 is heated by the hot oil.

The method for coating the electrode powder material by using the vapor phase atomic layer deposition device of this example, as shown in Figure 2, includes the following steps:

(a) loading the electrode powder material to be processed into the vacuum reaction chamber of the vapor phase atomic layer deposition device;

(b) Turn on the vacuum system to evacuate the vacuum reaction chamber to maintain effective isolation between the vacuum reaction chamber and the external air environment;

(c) Turn on the stirring device, and use the stirring device to raise the electrode powder material to fully disperse the electrode powder material;

(d) introducing the first gas phase precursor into the vacuum reaction chamber, so that the first gas phase precursor is adsorbed on the surface of the electrode powder material; the pulse time is 1-10 seconds, preferably 1-5 seconds;

(e) Pass the carrier gas to clean the excess first gas phase precursor in the reaction chamber, that is, remove the first gas phase precursor that is not adsorbed on the surface of the electrode powder material particles; during the cleaning process, it is usually not necessary to stop Stirring, the air suction port is equipped with a filter with a small pore size, so the electrode powder will not be sucked away;

(f) feed the second gas phase precursor into the vacuum reaction chamber, the pulse time is 1-10 seconds, preferably 1-5 seconds, so that the second gas phase precursor and the first gas phase precursor adsorbed on the surface of the electrode powder material A gas-phase precursor reacts to form a monoatomic layer film;

(g) Passing the carrier gas to clean the excess second gas-phase precursor in the reaction chamber, that is, to remove the second gas-phase precursor that did not participate in the reaction and the side effects of the reaction between the first gas-phase precursor and the second gas-phase precursor product;

Steps (d) to (g) are repeated until a cladding layer of a set thickness is obtained.

Wherein, in step (d) or (f), the rotational speed of the stirring device is adjusted according to the particle size and mass of the electrode powder material to be processed. Specifically, for micron-sized particles with a large original particle size and mass, adjust the rotation speed of the stirring device to 500-1000 revolutions per minute, which can effectively disperse the electrode powder material; for nano-sized particles with a small original particle size and mass, adjust the stirring The rotation speed of the device is 100-500 revolutions per minute, which can effectively disperse the electrode powder material.

For the pulse time of the first gas-phase precursor and the second gas-phase precursor, since the deposition process requires a certain amount of time for the precursor to be completely adsorbed on the particle surface, if the pulse time is less than 1 second, the amount of precursor provided by a single injection If it is too small, the electrode powder material particles that have been fully dispersed cannot be effectively coated; if the pulse time of the precursor is greater than 5 seconds, the incoming precursor will be sucked away by the vacuum pump, resulting in waste of the precursor; therefore, the pulse time of the precursor is 1 - 10 seconds, preferably 1-5 seconds.

In step (d) or (f), specifically, according to the degree of difficulty of different precursors on the surface of different lithium-ion battery powder particles, adjust the number of precursor pulses, preferably 10-20 times, usually If the number of injections is too small, the ratio of adsorption is not high; if the number of injections is too large, the increase in the number of injections will not contribute much to the adsorption of the precursor, and the precursor is sucked away by the vacuum pump, resulting in waste of the precursor. In this example, the precursor pulse refers to, for example, feeding the first precursor for 5 seconds, then stopping the feeding, and then feeding it for 5 seconds, stopping and feeding it for 5 seconds, and repeating this 10 times. It should be noted that, since the precursor is contained in the precursor container, and has a certain saturated vapor pressure; pass through for 5 seconds, stop; wait for the pressure in the precursor container to return to the saturated vapor pressure, and then pass through for 5 seconds; this can Increase the loading amount of the precursor; 5 seconds each time, 10 pulses, which is much larger than the loading amount of a single pass of 50 seconds. In addition, the pause time is usually about 2 seconds. In the process of introducing the precursor, if the pressure is maintained, the vacuum pump is turned off, and if the pressure is not maintained, the vacuum pump is turned on; whether to use pressure-maintaining adsorption or not to maintain pressure adsorption can be determined according to the difficulty of adsorption of each precursor.

The heating system in this example heats the wall of the vacuum reaction chamber, and heats the interior of the vacuum reaction chamber through the heat radiation of the wall, so that the electrode powder material particles therein reach the temperature required by the reaction conditions. The reaction conditions, That is, the reaction temperature of the first gas-phase precursor and the second gas-phase precursor, usually the temperature is between 50-300 degrees Celsius, and the specific reaction temperature depends on the specific first gas-phase precursor and the second gas-phase precursor. Certainly.

In addition, for the precursor itself that is passed into the vacuum reaction chamber, its temperature is controlled at 25-200 degrees Celsius. The higher the melting point of the precursor, the lower its saturated vapor pressure, and the less the amount of precursor that can participate in the reaction obtained under the same conditions. For ordinary precursors, the temperature is controlled at 25-100 degrees Celsius; for solid precursors with high melting points, the temperature can reach 200 degrees Celsius. The temperature of the precursor pipeline is controlled at 25-200 degrees Celsius to prevent condensation of the precursor in the delivery pipeline.

In this application, the precursor may be in gaseous, liquid, solid or plasma state. Liquid or solid precursors can be brought into the vacuum reaction chamber with carrier gas, and then cleaned with pure carrier gas; gaseous or plasma state precursors can be brought into the reaction chamber with carrier gas, or directly into the vacuum reaction chamber.

The carrier gas in this example is an inert gas, preferably nitrogen. The temperature of the carrier gas is 50-300 degrees Celsius. Generally speaking, the temperature of the carrier gas is equivalent to the reaction temperature in the vacuum reaction chamber to reduce the influence on the temperature uniformity of the reaction area inside the vacuum reaction chamber.

test 1

In this experiment, trimethylaluminum (abbreviated as TMA) and water are used as the first precursor and the second precursor respectively, and the lithium-ion battery powder material is coated and modified according to the steps shown in Figure 2 introduced above. ,specific:

Step 1: The lithium-ion battery powder material loaded into the reaction chamber is LiNiMnCoO ₂ ternary cathode material, and the particle size of the cathode material is about 10 microns.

The second step: the reaction chamber is vacuumed to maintain the effective isolation of the reaction chamber from the external air environment. Wherein, the degree of vacuum can reach 100-300mTorr, specifically 200mTorr in this example.

Step 3: Turn on the stirring device, and the rotating speed of the stirring device is 500 revolutions per minute, so that the lithium-ion battery powder materials of different masses and particle sizes are fully dispersed.

Step 4: The first gas-phase precursor, trimethylaluminum TMA, is fed into the reaction chamber with the aid of carrier gas _N2 , and the pulse time is 1 second. TMA is physically adsorbed on the surface of lithium-ion battery powder particles, and the TMA precursor is fed 10 times, the process does not pump the reaction chamber, and provides a higher pressure dwell time of 100-300 seconds. In this example, the specific dwell time is 200 seconds, increasing the contact time between the precursor TMA and the surface of the powder particles, so as to Improve coating uniformity and coating efficiency.

Step 5: Pass the carrier gas _N2 to clean the excess first gas-phase precursor in the reaction chamber, and remove the first gas-phase precursor that is not adsorbed on the surface of the lithium-ion battery powder particles, and the purge time is 30 seconds.

Step 6: The second gas-phase precursor water is the same as the method for depositing TMA in the fourth step. The water vapor is assisted by the carrier gas nitrogen into the reaction chamber, and the pressure is also maintained for 200 seconds. The water is adsorbed on the lithium-ion battery powder The surface of the particle reacts chemically with the precursor TMA previously adsorbed on the surface to form a monoatomic layer film.

The seventh step: the same cleaning method as the fifth step, removing the precursor water that has not reacted with the precursor TMA and the by-products of the reaction between the precursor TMA and the precursor water. Because the viscosity of water is stronger, the cleaning time can be extended appropriately. In this example, the specific extended cleaning time is 2 minutes.

Step 8: Repeat steps 4 to 7 according to the thickness of the coating modification layer required, and the coating modification layer of the desired thickness can be accurately obtained. This example was specifically repeated 10 times, and finally a coated modified layer with a thickness of about 3 nanometers was prepared.

The morphology of the particles before and after coating was observed with a transmission electron microscope (TEM), as shown in Figure 3. In Figure 3, (a) is the scanning result before coating, and (b) is the scanning result after coating. It can be seen that the coating layer is clearly visible, uniform in thickness, and has high shape retention.

test 2

In this experiment, diethyl zinc (abbreviated as DEZ) and water are used as the first precursor and the second precursor respectively, and the lithium-ion battery powder material is coated and modified according to the steps shown in Figure 2 introduced above. ,specific:

Step 1: The lithium-ion battery powder material loaded into the reaction chamber is LiNiMnCoO ₂ ternary cathode material, and the particle size of the cathode material is about 10 microns.

The second step: the reaction chamber is vacuumed to maintain the effective isolation of the reaction chamber from the external air environment. Wherein, the degree of vacuum can reach 100-300mTorr, specifically 200mTorr in this example.

Step 3: Turn on the stirring device, and the rotating speed of the stirring device is 500 revolutions per minute, so that the lithium-ion battery powder materials of different masses and particle sizes are fully dispersed.

Step 4: The first gas phase precursor, diethylzinc DEZ, is assisted by the carrier gas N ₂ into the reaction chamber, and the pulse time is 1 second. DEZ is physically adsorbed on the surface of the lithium-ion battery powder particles, and the DEZ precursor is introduced In this process, the reaction chamber is not evacuated, and a higher pressure holding time of 100-300 seconds is provided. In this example, the specific holding pressure is 200 seconds, and the contact time between the precursor DEZ and the surface of the powder particle is increased to increase the contact time between the precursor DEZ and the powder particle surface. Improve coating uniformity and coating efficiency.

Step 5: Pass the carrier gas _N2 to clean the excess first gas-phase precursor in the reaction chamber, and remove the first gas-phase precursor that is not adsorbed on the surface of the lithium-ion battery powder particles, and the purge time is 30 seconds.

Step 6: The second gas phase precursor, water H ₂ O, is the same as the method for depositing DEZ in the fourth step. The pressure is also kept for 200 seconds. A chemical reaction occurs to form a monoatomic layer of film.

The seventh step: the same cleaning method as the fifth step, removing the precursor water that failed to react with the precursor DEZ and the by-products of the reaction between the precursor DEZ and the precursor water. Because the viscosity of water is stronger, the cleaning time can be extended appropriately. In this example, the specific extended cleaning time is 2 minutes.

Step 8: Repeat steps 4 to 7 according to the thickness of the coating modification layer required, and the coating modification layer of the desired thickness can be accurately obtained. This example was specifically repeated 10 times, and finally a coated modified layer with a thickness of about 3 nanometers was prepared.

Using a transmission electron microscope (TEM) to observe the morphology of the particles before and after coating, it can be seen that the coating layer is clearly visible, the thickness is uniform, the coating uniformity is good, and it has high shape retention; moreover, the particle size before and after coating is uniform, and there is almost no agglomeration phenomenon .

Test 3

In this experiment, tetrakis(dimethylamino)titanium (abbreviated TDMAT) and water were used as the first precursor and the second precursor respectively, and the lithium-ion battery powder material was packaged according to the steps shown in Figure 2 introduced above. Modified, specifically:

Step 1: The lithium-ion battery powder material loaded into the reaction chamber is LiNiMnCoO ₂ ternary cathode material, and the particle size of the cathode material is about 10 microns.

The second step: the reaction chamber is vacuumed to maintain the effective isolation of the reaction chamber from the external air environment. Wherein, the degree of vacuum can reach 100-300mTorr, specifically 200mTorr in this example.

Step 3: Turn on the stirring device, and the rotating speed of the stirring device is 500 revolutions per minute, so that the lithium-ion battery powder materials of different masses and particle sizes are fully dispersed.

The fourth step: the first gaseous phase precursor tetrakis(dimethylamino)titanium TDMAT is assisted by the carrier gas N ₂ into the reaction chamber, the pulse time is 1 second, and TDMAT is physically adsorbed on the surface of the lithium-ion battery powder particles. Inject the TDMAT precursor 10 times. During this process, the reaction chamber is not pumped, and a higher pressure holding time of 100-300 seconds is provided. In this example, the specific holding pressure is 200 seconds to increase the contact between the precursor TDMAT and the surface of the powder particles. Time to improve coating uniformity and coating efficiency.

Step 5: Pass the carrier gas _N2 to clean the excess first gas-phase precursor in the reaction chamber, and remove the first gas-phase precursor that is not adsorbed on the surface of the lithium-ion battery powder particles, and the purge time is 30 seconds.

Step 6: The second gas phase precursor, water H ₂ O, is the same as the method for depositing TDMAT in the fourth step, and the pressure is also maintained for 200 seconds. A chemical reaction occurs to form a monoatomic layer of film.

The seventh step: the same cleaning method as the fifth step, removing the precursor water that failed to react with the precursor TDMAT and the by-products of the reaction between the precursor TDMAT and the precursor water. Because the viscosity of water is stronger, the cleaning time can be extended appropriately. In this example, the specific extended cleaning time is 2 minutes.

Step 8: Repeat steps 4 to 7 according to the thickness of the coating modification layer required, and the coating modification layer of the desired thickness can be accurately obtained. This example was repeated 60 times, and finally a coated modified layer with a thickness of about 3 nanometers was prepared.

Using a transmission electron microscope (TEM) to observe the morphology of the particles before and after coating, it can be seen that the coating layer is clearly visible, the thickness is uniform, the coating uniformity is good, and it has high shape retention; moreover, the particle size before and after coating is uniform, and there is almost no agglomeration phenomenon .

Test 4

In this experiment, tantalum tris(diethylamino)tert-butyramide (abbreviated TBTDET) and water were used as the first precursor and the second precursor respectively. Coating modification of body materials, specifically:

Step 1: The lithium-ion battery powder material loaded into the reaction chamber is LiNiMnCoO ₂ ternary cathode material, and the particle size of the cathode material is about 10 microns.

The second step: the reaction chamber is vacuumed to maintain the effective isolation of the reaction chamber from the external air environment. Wherein, the degree of vacuum can reach 100-300mTorr, specifically 200mTorr in this example.

Step 3: Turn on the stirring device, and the rotating speed of the stirring device is 500 revolutions per minute, so that the lithium-ion battery powder materials of different masses and particle sizes are fully dispersed.

Step 4: The first gaseous precursor tris(diethylamino)tert-butyramide tantalum TBTDET is assisted by the carrier gas N ₂ into the reaction chamber, the pulse time is 1 second, and TBTDET is physically adsorbed on the lithium-ion battery powder particles The surface of the TBTDET precursor is injected 10 times. In this process, the reaction chamber is not pumped, and a higher pressure holding time of 100-300 seconds is provided. In this example, the specific holding pressure is 200 seconds, and the precursor TBTDET and powder are added. The contact time of the particle surface to improve coating uniformity and coating efficiency.

Step 5: Pass the carrier gas _N2 to clean the excess first gas-phase precursor in the reaction chamber, and remove the first gas-phase precursor that is not adsorbed on the surface of the lithium-ion battery powder particles, and the purge time is 30 seconds.

Step 6: The second gas phase precursor, water H ₂ O, is the same as the method for depositing TBTDET in the fourth step, and the pressure is also maintained for 200 seconds. A chemical reaction occurs to form a monoatomic layer of film.

The seventh step: the same cleaning method as the fifth step, removing the precursor water that failed to react with the precursor TBTDET and the by-products of the reaction between the precursor TBTDET and the precursor water. Because the viscosity of water is stronger, the cleaning time can be extended appropriately. In this example, the specific extended cleaning time is 2 minutes.

Step 8: Repeat steps 4 to 7 according to the thickness of the coating modification layer required, and the coating modification layer of the desired thickness can be accurately obtained. This example was specifically repeated 10 times, and finally a coated modified layer with a thickness of about 1 nanometer was prepared.

Using a transmission electron microscope (TEM) to observe the morphology of the particles before and after coating, it can be seen that the coating layer is clearly visible, the thickness is uniform, the coating uniformity is good, and it has high shape retention; moreover, the particle size before and after coating is uniform, and there is almost no agglomeration phenomenon .

Test 5

In this experiment, four (ethylmethylamino) hafnium (abbreviated as TEMAH) and water were used as the first precursor and the second precursor respectively. The material is coated and modified, specifically:

Step 1: The lithium-ion battery powder material loaded into the reaction chamber is LiNiMnCoO ₂ ternary cathode material, and the particle size of the cathode material is about 10 microns.

The second step: the reaction chamber is vacuumed to maintain the effective isolation of the reaction chamber from the external air environment. Wherein, the degree of vacuum can reach 100-300mTorr, specifically 200mTorr in this example.

Step 3: Turn on the stirring device, and the rotating speed of the stirring device is 500 revolutions per minute, so that the lithium-ion battery powder materials of different masses and particle sizes are fully dispersed.

Step 4: The first gas phase precursor tetrakis (ethylmethylamino) hafnium TEMAH is assisted by the carrier gas N ₂ into the reaction chamber, the pulse time is 1 second, and TEMAH is physically adsorbed on the lithium-ion battery powder particles On the surface, the TEMAH precursor is injected 10 times. During this process, the reaction chamber is not pumped, and a relatively high pressure holding time of 100-300 seconds is provided. In this example, the specific holding pressure is 200 seconds, and the precursor TEMAH and powder particles are added. Surface contact time to improve coating uniformity and coating efficiency.

Step 5: Pass the carrier gas _N2 to clean the excess first gas-phase precursor in the reaction chamber, and remove the first gas-phase precursor that is not adsorbed on the surface of the lithium-ion battery powder particles, and the purge time is 30 seconds.

Step 6: The second gas phase precursor, water H ₂ O, is the same as the method for depositing TEMAH in the fourth step, and the pressure is also maintained for 200 seconds. A chemical reaction occurs to form a monoatomic layer of film.

The seventh step: the same cleaning method as the fifth step, remove the precursor water that has not reacted with the precursor TEMAH and the by-products of the reaction between the precursor TEMAH and the precursor water. Because the viscosity of water is stronger, the cleaning time can be extended appropriately. In this example, the specific extended cleaning time is 2 minutes.

Step 8: Repeat steps 4 to 7 according to the thickness of the coating modification layer required, and the coating modification layer of the desired thickness can be accurately obtained. This example was repeated 50 times, and finally a coating modification layer with a thickness of about 3 nanometers was prepared.

Using a transmission electron microscope (TEM) to observe the morphology of the particles before and after coating, it can be seen that the coating layer is clearly visible, the thickness is uniform, the coating uniformity is good, and it has high shape retention; moreover, the particle size before and after coating is uniform, and there is almost no agglomeration phenomenon .

The vapor phase atomic layer deposition device used for the coating and modification of lithium-ion battery electrode powder materials in this example introduces a stirring device and independently adjusts the rotation speed of the stirring device to achieve sufficient particle size and quality of lithium-ion battery electrode powder materials. Dispersion can effectively reduce the degree of powder agglomeration, facilitate the adsorption and reaction of precursors, improve the coating uniformity and coating efficiency, and is suitable for large-scale high-quality deposition.

The above content is a further detailed description of the present application in conjunction with specific implementation modes, and it cannot be considered that the specific implementation of the present application is limited to these descriptions. For those of ordinary skill in the technical field to which this application belongs, some simple deduction or substitutions can be made without departing from the concept of this application, which should be deemed to belong to the protection scope of this application.

Claims (10)

1. A vapor phase atomic layer deposition device for electrode powder material coating, comprising a vacuum reaction chamber and a monitoring system, characterized in that: a stirring device is arranged in the vacuum reaction chamber, and the stirring device and the The monitoring system is electrically connected or signal connected, and the operation of the stirring device is controlled through the monitoring system. 2. The vapor phase atomic layer deposition device according to claim 1, characterized in that: it also includes a vacuum system, a precursor system and a heating system; the vacuum system is used to evacuate the vacuum reaction chamber, and the precursor system Used to provide precursors to the vacuum reaction chamber, the heating system is used to heat the vacuum reaction chamber, the monitoring system is used to detect the temperature and pressure inside and outside the vacuum reaction chamber, and control the vacuum system, precursor system and Turning on or off of the heating system. 3. The vapor phase atomic layer deposition device according to claim 1, wherein the stirring device is at least one of paddle stirring, turbine stirring and frame stirring. 4. The vapor phase atomic layer deposition device according to any one of claims 1-3, characterized in that: the vacuum reaction chamber is composed of an upper chamber and a lower chamber, and one end of the stirring device is fixed on the upper chamber The top of the body, and the other end extends into the lower cavity. 5. The application of the vapor phase atomic layer deposition device according to any one of claims 1-4 in the surface coating of powder materials. 6. A method for coating an electrode powder material, the electrode powder material being a positive electrode powder material for a lithium ion battery or a negative electrode powder material for a lithium ion battery, characterized in that: the method comprises the steps of claim 1-4 The gas-phase atomic layer deposition device described in any one of the above-mentioned devices can coat and modify electrode powder materials. 7. The method according to claim 6, characterized in that: said method comprises the following steps, (a) loading the electrode powder material to be processed into the vacuum reaction chamber of the vapor phase atomic layer deposition device; (b) vacuumize the vacuum reaction chamber; (c) using the stirring device to raise the electrode powder material to fully disperse it; (d) Passing the first gas phase precursor into the vacuum reaction chamber to make it adsorb on the surface of the electrode powder material; (e) feed carrier gas to remove excess first gas phase precursor in the vacuum reaction chamber; (f) introducing a second gas-phase precursor into the vacuum reaction chamber to react with the first gas-phase precursor adsorbed on the surface of the electrode powder material to form a coating layer; (g) feed the carrier gas to remove the redundant second gas phase precursor in the vacuum reaction chamber; Steps (d) to (g) are repeated until a coating of a defined thickness or structure is obtained. 8. The method according to claim 7, characterized in that: the stirring speed of the stirring device is 100-1000 revolutions per minute. 9. The method according to claim 7, characterized in that: in the vacuum reaction chamber, the reaction temperature of the first gas-phase precursor and the second gas-phase precursor is 50-300°C. 10. The method according to claim 7, characterized in that: the temperature of the carrier gas is 50-300°C, the carrier gas is an inert gas, preferably, the carrier gas is argon or nitrogen.