A multilayer lithium-based metal composite powder, a preparation method and application thereof

Abstract

The application provides a multilayer lithium-based metal composite powder and a preparation method and application thereof, and belongs to the technical field of lithium-based material development. The multilayer lithium-based metal composite powder provided by the application has a multilayer structure in a single particle microstructure, which comprises a lithium-based metal layer and inert material layers located on both sides of the lithium-based metal layer. The structure overcomes the poor stability problem of lithium-based metal powder materials in the prior art. In the multilayer lithium-based metal composite powder provided by the application, the inert material layers located on both sides of the lithium-based metal layer play a coating role, so that the lithium-based metal powder not only has the lithium-based metal properties, but also can exist stably in an atmospheric environment, the application limitation caused by the instability of the lithium-based metal material is solved, and a new product is provided for popularizing and applying the lithium-based metal material.

Description

Technical Field

[0001] This invention relates to the field of lithium-based material development technology, and in particular to a multilayer lithium-based metal composite powder, its preparation method, and its application. Background Technology

[0002] Lithium metal powder and lithium alloy powder are widely used in applications such as alkyl lithium, catalysts, polymers, lithium batteries, and aerospace. However, due to the high reactivity, high viscosity, and low melting point (180.5℃) of lithium metal, it is difficult to prepare lithium metal powder and lithium alloy powder by conventional methods such as mechanical crushing.

[0003] Existing technologies employ a melt dispersion method to prepare potassium metal powder and potassium alloy powder. This method involves heating potassium metal or potassium alloy to a melt and then atomizing it into droplets through high-speed stirring or atomization, followed by cooling to form powder. This method requires the use of high-boiling-point hydrocarbon oils and low-boiling-point hydrocarbon oils for washing, resulting in high production costs, low production efficiency, and uneven product structure. Chinese patent CN113319286B discloses a lithium powder production method that uses high-pressure equipment to collide molten lithium metal with a baffle in the form of a jet to obtain lithium metal powder. However, the potassium metal or potassium alloy powder prepared in the above manner is still not stable in the environment, exhibiting defects such as easy oxidation, easy moisture absorption, easy chemical reaction with environmental media, and the formation of lithium dendrites during charging and discharging when used as a negative electrode in capacitor manufacturing. Summary of the Invention

[0004] The purpose of this invention is to provide a multilayer lithium-based metal composite powder to solve the problem of poor stability of lithium-based metal powder materials in the prior art.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a multilayer lithium-based metal composite powder, which is a composite powder prepared from lithium-based metal and inert materials.

[0007] The single-particle microstructure of the multilayer lithium-based metal composite powder is a multilayer structure, which includes a lithium-based metal layer and inert material layers located on both sides of the lithium-based metal layer.

[0008] Preferably, the inert material is selected from one or more of carbon materials, titanium, chromium, nickel, metal oxides, metal nitrides, metal carbides, stainless steel, or ceramics.

[0009] Preferably, the lithium-based metal is metallic lithium or a lithium-based alloy.

[0010] Preferably, the lithium content of the lithium-based alloy is 0.1% to 99.9% by mass.

[0011] Preferably, the thickness of the lithium-based metal layer and the inert material layer is 0.1 nm to 10 μm.

[0012] The present invention also provides a method for preparing the above-mentioned multilayer lithium-based metal composite powder, comprising the following steps:

[0013] S1. An inert material is coated onto the substrate surface using vapor deposition technology to obtain an inert material layer;

[0014] S2. A lithium-based metal layer is obtained by coating the surface of an inert material layer with a vapor deposition technique;

[0015] S3. An inert material is coated onto the surface of a lithium-based metal layer using vapor deposition technology to obtain an inert material layer. The inert material layer is formed on both sides of the lithium-based metal layer on the substrate surface.

[0016] S4. Repeat S2 to S3, the number of repetitions being 0 to 1000 times, to obtain a composite film layer on the substrate surface;

[0017] S5. The composite film layer on the surface of the substrate is pulverized to obtain multilayer lithium-based metal composite powder.

[0018] Preferably, the vapor deposition technology includes physical vapor deposition, chemical vapor deposition, and a combination of physical and chemical vapor deposition.

[0019] The physical vapor deposition techniques include vacuum evaporation, magnetron sputtering, ion beam sputtering, arc plasma deposition, pulsed laser deposition, atomic layer deposition, or electron beam evaporation.

[0020] The chemical vapor deposition technology includes thermal CVD, plasma-assisted CVD, or MOCVD.

[0021] Preferably, steps S1 to S4 are performed under vacuum conditions;

[0022] The vacuum level of the vacuum condition is 5 × 10⁻⁶. -4 ~5×10 4 Pa.

[0023] Preferably, steps S1 to S4 are performed in the presence of process gas;

[0024] The process gas is one or more of argon, nitrogen, oxygen, carbon-containing gas, or lithium-containing gas.

[0025] The present invention also provides the application of the above-mentioned multilayer lithium-based metal composite powder and the multilayer lithium-based metal composite powder obtained by the above preparation method in the preparation of capacitors, ceramics, glass, lubricants, refrigerants, nuclear industry materials or fillers.

[0026] The beneficial effects of this invention are:

[0027] In the multilayer lithium-based metal composite powder provided by this invention, the inert material layers located on both sides of the lithium-based metal layer play a coating role, enabling the lithium-based metal powder to not only have the basic properties of lithium but also to exist stably in the atmospheric environment. This removes the application limitations caused by the instability of lithium-based metal materials and provides a new product for the promotion and application of lithium-based metal materials. Attached Figure Description

[0028] Figure 1 Characteristic image of lithium-based metal composite powder, scale bar: 30μm;

[0029] Figure 2 Characteristic image of lithium-based metal composite powder, scale bar: 8μm;

[0030] Figure 3 This is a characteristic image of lithium-based metal composite powder, scale bar: 2μm. Detailed Implementation

[0031] This invention provides a multilayer lithium-based metal composite powder, which is a composite powder prepared from lithium-based metal and inert materials. The single-particle microstructure of the multilayer lithium-based metal composite powder is a multilayer structure, which includes a lithium-based metal layer and inert material layers located on both sides of the lithium-based metal layer. The inert material is preferably one or more of carbon materials, titanium, chromium, nickel, metal oxides, metal nitrides, metal carbides, stainless steel, or ceramics. The lithium-based metal is preferably lithium metal or a lithium-based alloy. The lithium content of the lithium-based alloy is preferably 0.1-99.9% by mass. The thickness of the lithium-based metal layer and the inert material layer is preferably 0.1 nm-10 μm, and more preferably 100-300 nm.

[0032] The present invention also provides a method for preparing the above-mentioned multilayer lithium-based metal composite powder, comprising the following steps:

[0033] S1. An inert material is coated onto the substrate surface using vapor deposition technology to obtain an inert material layer;

[0034] S2. A lithium-based metal layer is obtained by coating the surface of an inert material layer with a vapor deposition technique;

[0035] S3. An inert material is coated onto the surface of a lithium-based metal layer using vapor deposition technology to obtain an inert material layer;

[0036] S4. Repeat S2 to S3, the number of repetitions being 0 to 1000 times, to obtain a composite film layer on the substrate surface;

[0037] S5. The composite film layer on the surface of the substrate is pulverized to obtain multilayer lithium-based metal composite powder.

[0038] In this invention, the vapor deposition technology includes physical vapor deposition, chemical vapor deposition, and physical-chemical vapor deposition; the physical vapor deposition technology includes vacuum evaporation, magnetron sputtering, ion beam sputtering, arc plasma deposition, pulsed laser deposition, atomic layer deposition, or electron beam evaporation; the chemical vapor deposition technology includes thermal CVD, plasma-assisted CVD, or MOCVD.

[0039] Steps S1 to S4 are preferably performed under vacuum conditions, wherein the vacuum degree is 5 × 10⁻⁶. -5 ~5×10 4 Pa, wherein S1 to S4 are preferably carried out in the presence of a process gas, which is one or more of argon, nitrogen, oxygen, lithium-containing gas or carbon-containing gas.

[0040] Prior to step S1, it is preferable to pre-treat the substrate. The pre-treatment includes uniformly spraying a liquid reagent onto the substrate surface to form a dry solid layer that is easy to peel off, vaporizes, and has no significant impact on the composition of the composite film in subsequent processes, thus facilitating the subsequent peeling of the composite film. When the surface hardness of the substrate is low (e.g., when graphite, flexible plastic, or other materials are used), pre-treatment is not required.

[0041] The present invention also provides the application of the above-mentioned multilayer lithium-based metal composite powder and the multilayer lithium-based metal composite powder obtained by the above preparation method in the preparation of capacitors, ceramics, glass, lubricants, refrigerants, nuclear industry materials or fillers.

[0042] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0043] Example 1

[0044] The equipment used to prepare lithium-based metal composite powder is characterized by a single-chamber system with a vacuum chamber diameter of 1m and a height of 1m.

[0045] Vacuuming is performed using a combination of mechanical and molecular pumps, achieving an ultimate vacuum of 10. -4 Pa; The deposition source is a rectangular magnetron sputtering deposition source with a height of 900 mm and a width of 100 mm, which is vertically fixed on the wall of the vacuum chamber. There are 3 such sources, each with a graphite target, a lithium-magnesium alloy target, and a metallic nickel target.

[0046] The process gas used is argon, which is precisely measured and introduced into the vacuum chamber by a gas mass flow meter during the process.

[0047] The substrate is a mirror-finished stainless steel cylinder, 800mm high and 800mm in diameter, and is connected to a rotating frame located at the top of the vacuum chamber. When the rotating frame rotates, it drives the substrate to rotate.

[0048] At a location separated from the deposition source by the substrate, a steel brush with a length of 800 mm and a width of 100 mm is used as a lithium-based metal composite powder stripping mechanism. The steel brush is non-rotatable and fixed to the wall of the vacuum chamber. It can be in two states: with a gap or in close contact with the substrate, which can be selected according to the process requirements. At the bottom of the steel brush, a disc with a depth of 100 mm is placed as a collector for the prepared powder.

[0049] Preparation process:

[0050] 1. Open the vacuum chamber, the deposition source target and substrate are in place, and check that the substrate is rotating properly;

[0051] 2. Close the vacuum chamber and start the vacuum system. The vacuum chamber should reach a vacuum level of 5 × 10⁻⁶. -3 Pa;

[0052] 3. Drive the substrate to rotate at a speed of 5 r / min;

[0053] 4. Input process gas Ar until the vacuum level is 0.5 Pa;

[0054] 5. Start the magnetron sputtering source for the graphite target, with a process voltage of 600V and a current density of 10mA / cm². 2 Turn off after 1 minute;

[0055] 6. Start the magnetron sputtering source for the lithium-magnesium alloy target, with a process voltage of 600V and a current density of 10mA / cm². 2 Turn off after 5 minutes;

[0056] 7. Start the magnetron sputtering source for the nickel target, with a process voltage of 600V and a current density of 10mA / cm². 2 Turn off after 1 minute;

[0057] 8. Adjust the distance between the steel brush and the substrate so that the steel brush is pressed tightly against the substrate. After 1 minute, separate the steel brush from the substrate.

[0058] 9. Stop process gas input, stop substrate rotation, and stop vacuum system operation;

[0059] 10. Allow the vacuum chamber to cool, then introduce dry air at a flow rate of 1 L / min until the internal pressure of the vacuum chamber reaches one atmosphere.

[0060] 11. Open the vacuum chamber and take out the prepared lithium-based metal composite powder.

[0061] The single-particle microstructure of the prepared lithium-based metal composite powder is a three-layer structure, consisting of a graphite layer (99.99%), a lithium-magnesium alloy layer (LiMg), and a pure nickel layer (99.9%), with thicknesses of 20 nm, 100 nm, and 20 nm, respectively.

[0062] Example 2

[0063] The equipment used to prepare lithium-based metal composite powder is characterized by a single-chamber system with a vacuum chamber diameter of 1m and a height of 1m.

[0064] Vacuuming is performed using a combination of mechanical and molecular pumps, achieving an ultimate vacuum of 10. -4 Pa; The deposition source is a rectangular arc deposition source with a height of 900 mm and a width of 100 mm, which is vertically fixed on the wall of the vacuum chamber. There are 3 such sources, each with a titanium metal target, a pure lithium target, and a chromium metal target.

[0065] The process gas used is argon, which is precisely measured and introduced into the vacuum chamber by a gas mass flow meter during the process.

[0066] The substrate is a mirror-finished stainless steel cylinder, 800mm high and 800mm in diameter, and is connected to a rotating frame located at the top of the vacuum chamber. When the rotating frame rotates, it drives the substrate to rotate.

[0067] At a location separated from the deposition source by the substrate, a steel brush with a length of 800 mm and a width of 100 mm is used as a lithium-based metal composite powder stripping mechanism. The steel brush is non-rotatable and fixed to the wall of the vacuum chamber. It can be in two states: with a gap or in close contact with the substrate, which can be selected according to the process requirements. At the bottom of the steel brush, a disc with a depth of 100 mm is placed as a collector for the prepared powder.

[0068] Preparation process:

[0069] 1. Open the vacuum chamber, the deposition source target and substrate are in place, and check that the substrate is rotating properly;

[0070] 2. Close the vacuum chamber and start the vacuum system. The vacuum chamber should reach a vacuum level of 5 × 10⁻⁶. -3 Pa;

[0071] 3. Drive the substrate to rotate at a speed of 5 r / min;

[0072] 4. Input process gas Ar until the vacuum level is 0.5 Pa;

[0073] 5. Start the magnetron sputtering source for the titanium target, with a process power of 2kW, and turn it off after 1 minute;

[0074] 6. Start the pure lithium target magnetron sputtering source, with a process power of 2kW, and turn it off after 5 minutes;

[0075] 7. Start the magnetron sputtering source for the chromium metal target. The process power is 2kW. Turn it off after 1 minute.

[0076] 8. Adjust the distance between the steel brush and the substrate so that the steel brush is pressed tightly against the substrate. After 1 minute, separate the steel brush from the substrate.

[0077] 9. Stop process gas input, stop substrate rotation, and stop vacuum system operation;

[0078] 10. Allow the vacuum chamber to cool, then introduce dry air at a flow rate of 1 L / min until the internal pressure of the vacuum chamber reaches one atmosphere.

[0079] 11. Open the vacuum chamber and take out the prepared lithium-based metal composite powder.

[0080] The prepared lithium-based metal composite powder has a single-particle microstructure of three layers, consisting of a titanium layer, a pure lithium layer, and a pure chromium layer, with thicknesses of 40 nm, 200 nm, and 40 nm, respectively.

[0081] Example 3

[0082] The equipment used to prepare lithium-based metal composite powder is characterized by a single-chamber system with a vacuum chamber diameter of 1m and a height of 1m.

[0083] Vacuuming is performed using a combination of mechanical and molecular pumps, achieving an ultimate vacuum of 10. -4 Pa; The deposition source is a rectangular radio frequency plasma CVD coating source with a height of 900 mm and a width of 100 mm, which is vertically fixed on the wall of the vacuum chamber, with a total of 3 units;

[0084] The process gases used are acetylene, which is used as a raw material for carbon film, and methyl lithium (a vaporizable lithium salt carried by a carrier gas), which is used as a raw material for metallic lithium. During the process, the gases are accurately measured by a gas mass flow meter and input into the vacuum chamber.

[0085] The substrate is a mirror-finished stainless steel cylinder, 800mm high and 800mm in diameter, and is connected to a rotating frame located at the top of the vacuum chamber. When the rotating frame rotates, it drives the substrate to rotate.

[0086] At a location separated from the deposition source by the substrate, a steel brush with a length of 800 mm and a width of 100 mm is used as a lithium-based metal composite powder stripping mechanism. The steel brush is non-rotatable and fixed to the wall of the vacuum chamber. It can be in two states: with a gap or in close contact with the substrate, which can be selected according to the process requirements. At the bottom of the steel brush, a disc with a depth of 100 mm is placed as a collector for the prepared powder.

[0087] Preparation process:

[0088] 1. Open the vacuum chamber, the substrate is in place, and check that the substrate rotation is in good condition;

[0089] 2. Close the vacuum chamber and start the vacuum system. The vacuum chamber should reach a vacuum level of 5 × 10⁻⁶. -3 Pa;

[0090] 3. Drive the substrate to rotate at a speed of 5 r / min;

[0091] 4. Input process gas acetylene to a vacuum level of 0.5 Pa;

[0092] 5. Start the RF CVD operation with a process power supply of 2kW. After 2 minutes, the process gas and RF power supply will be turned off.

[0093] 6. Start the process gas lithium methyl gas to a vacuum level of 0.5 Pa, start the RF CVD operation, and the power supply during the process is 2kW. After 10 minutes, the process gas and RF power supply are turned off.

[0094] 7. Start the process gas acetylene input until the vacuum degree is 0.5Pa, start the RF CVD operation, the RF power supply power is 2kW during the process, and it is turned off after 2 minutes;

[0095] 8. Adjust the distance between the steel brush and the substrate so that the steel brush is pressed tightly against the substrate. After 1 minute, separate the steel brush from the substrate.

[0096] 9. Stop process gas input, stop substrate rotation, and stop vacuum system operation;

[0097] 10. Allow the vacuum chamber to cool, then introduce dry air at a flow rate of 1 L / min until the internal pressure of the vacuum chamber reaches one atmosphere.

[0098] 11. Open the vacuum chamber and take out the prepared lithium-based metal composite powder.

[0099] The single-particle microstructure of the prepared lithium-based metal composite powder is a three-layer structure, consisting of a graphite layer (99.99%), a lithium metal layer, and another graphite layer (99.99%), with thicknesses of 10 nm, 50 nm, and 10 nm, respectively.

[0100] Experimental Example 1

[0101] The lithium-based metal composite powder obtained in Example 1 was observed, and the results are as follows: Figures 1-3 As shown in the figure, the lithium-based metal composite powder provided by this invention can be measured in micrometers or sub-millimeters in length and width, while its thickness is only in the nanometer range.

[0102] A 72-hour high-temperature and high-humidity test was conducted under environmental conditions of 95% humidity and 50℃. The results are shown in Table 1 below.

[0103] Table 1. Results of High Temperature and High Humidity Tests

[0104]

[0105] As shown in Table 1, all composite powders obtained by this invention have excellent resistance to high temperature and high humidity, achieving performance improvement over pure metallic lithium or lithium alloys. It can be seen that, since the composite powders obtained by this invention are protected by inner and outer inert material layers, the lithium-based metals therein will not oxidize in the air. When applied to, for example, lithium replenishment of lithium battery anode materials, it will significantly improve the lithium storage capacity of the anode material, while avoiding the lithium plating phenomenon that occurs when traditional metallic lithium is used as an anode.

[0106] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A multilayer lithium-based metal composite powder, characterized in that, The multilayer lithium-based metal composite powder is a composite powder prepared from lithium-based metal and inert materials. The single-particle microstructure of the multilayer lithium-based metal composite powder is a multilayer structure, which includes a lithium-based metal layer and inert material layers located on both sides of the lithium-based metal layer. The preparation method of the multilayer lithium-based metal composite powder includes the following steps: S1. An inert material is coated onto the substrate surface using vapor deposition technology to obtain an inert material layer; S2. A lithium-based metal layer is obtained by coating the surface of an inert material layer with a vapor deposition technique; S3. An inert material is coated onto the surface of a lithium-based metal layer using vapor deposition technology to obtain an inert material layer. The inert material layer is formed on both sides of the lithium-based metal layer on the substrate surface. S4. Repeat S2 to S3, the number of repetitions being 0 to 1000 times, to obtain a composite film layer on the substrate surface; S5. The composite film layer on the surface of the substrate is pulverized to obtain multilayer lithium-based metal composite powder; The vapor deposition technique is physical vapor deposition or a combination of physical and chemical vapor deposition. The physical vapor deposition techniques include vacuum evaporation, magnetron sputtering, ion beam sputtering, arc plasma deposition, pulsed laser deposition, atomic layer deposition, or electron beam evaporation. The inert material is selected from one or more of carbon materials, titanium, chromium, nickel, metal oxides, metal nitrides, metal carbides, or stainless steel; The lithium-based metal is metallic lithium or a lithium-based alloy; S1 to S4 are performed under vacuum conditions; The vacuum level of the vacuum condition is 5 × 10⁻⁶. -4 ~5×10 4 Pa; S1 to S4 are carried out in the presence of process gas; The process gas is argon or nitrogen; The thickness of the lithium-based metal layer and the inert material layer is 0.1 nm to 10 μm.

2. The multilayer lithium-based metal composite powder according to claim 1, characterized in that, The lithium-based alloy contains 0.1% to 99.9% lithium by mass.

3. The method for preparing the multilayer lithium-based metal composite powder according to any one of claims 1 to 2, characterized in that, Includes the following steps: S1. An inert material is coated onto the substrate surface using vapor deposition technology to obtain an inert material layer; S2. A lithium-based metal layer is obtained by coating the surface of an inert material layer with a vapor deposition technique; S3. An inert material is coated onto the surface of a lithium-based metal layer using vapor deposition technology to obtain an inert material layer. The inert material layer is formed on both sides of the lithium-based metal layer on the substrate surface. S4. Repeat S2 to S3, the number of repetitions being 0 to 1000 times, to obtain a composite film layer on the substrate surface; S5. The composite film layer on the surface of the substrate is pulverized to obtain multilayer lithium-based metal composite powder; The vapor deposition technique is physical vapor deposition or a combination of physical and chemical vapor deposition. The physical vapor deposition techniques include vacuum evaporation, magnetron sputtering, ion beam sputtering, arc plasma deposition, pulsed laser deposition, atomic layer deposition, or electron beam evaporation. S1 to S4 are performed under vacuum conditions; The vacuum level of the vacuum condition is 5 × 10⁻⁶. -4 ~5×10 4 Pa; S1 to S4 are carried out in the presence of process gas; The process gas is argon or nitrogen.

4. The application of the multilayer lithium-based metal composite powder according to any one of claims 1 to 2 or the multilayer lithium-based metal composite powder obtained by the preparation method according to claim 3 in the preparation of capacitors, ceramics, glass, lubricants, refrigerants, nuclear industry materials or fillers.

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