Powder material and method for producing the same, electrode material

Abstract

The application discloses a powder material, a preparation method of the powder material, and an electrode material, and the powder material comprises raw materials and a refining agent; the refining agent comprises at least one of silicon, di-aluminum oxide, cerium oxide, titanium dioxide, lanthanum oxide, silicon dioxide, zirconium dioxide, nickel oxide, iron oxide, silver, aluminum and iron; the raw materials comprise silicon; or a combination of silicon and aluminum; and the adding amount of the refining agent is 0.01% to 2% of the mass of the raw materials. The new refining agent is used, the grain size of the powder material can be effectively refined, and the refining agent is easy to obtain.

Description

Technical Field

[0001] This application relates to the field of inorganic materials technology, specifically to powder materials and their preparation methods, and electrode materials. Background Technology

[0002] Powder metallurgy possesses unique chemical compositions and mechanical and physical properties that cannot be achieved using traditional casting methods. Due to its advantages, powder metallurgy technology is widely used in transportation, machinery, electronics, aerospace, weaponry, biology, new energy, information technology, and nuclear industries, becoming a key to solving new materials problems and playing a crucial role in the development of new materials. To meet the needs of various fields, the requirements for powder materials are becoming increasingly stringent, especially the standards for particle size and morphology, which are receiving significant attention.

[0003] Grain size has a significant impact on the properties of powder materials. Taking alloy powder as an example, at room temperature, the smaller the grain size, the higher the strength and hardness of the metal, and the better its plasticity and toughness. Currently, common methods for refining grain size include: (1) increasing the degree of supercooling; (2) grain refinement treatment; and (3) vibration treatment. Among these, the grain refinement treatment mainly involves adding a certain chemical element or compound (modifier) ​​to the liquid metal. Commonly used grain refiners include titanium bulk grain refiners, salt grain refiners, and intermediate alloy grain refiners. These grain refiners have the problem of being difficult to synthesize. In addition, grain refiners containing phosphorus can cause significant corrosion to equipment. Therefore, developing suitable grain refiners is of great significance for the preparation of high-performance alloy powders. Summary of the Invention

[0004] This application aims to at least partially solve one of the technical problems in the related art. Therefore, one objective of this application is to provide powder materials and their preparation methods, as well as electrode materials. The powder materials of this application employ novel grain refiners that can effectively refine the grain size of the powder materials, and these grain refiners are readily available.

[0005] The first aspect of this application discloses a powder material. According to an embodiment of this application, the powder material comprises: a raw material and a refining agent; The refining agent includes at least one of silicon, aluminum oxide, cerium oxide, titanium dioxide, lanthanum oxide, silicon dioxide, zirconium dioxide, nickel oxide, iron oxide, silver, aluminum, and iron; The raw materials include: silicon; or a combination of silicon and aluminum; The amount of finer agent added is 0.01% to 2% of the mass of the raw material.

[0006] The powder material proposed in this application uses silicon-containing materials as raw materials, specifically two types: one is silicon; the other is a combination of silicon and aluminum. When preparing the powder material using the above raw materials, during the heating process to prepare the melt, the silicon in the raw materials first precipitates out and becomes solid. By adding a grain refiner, which mainly acts on the silicon, it can serve as a nucleation site for the precipitated silicon, promoting the refinement of silicon grains and obtaining nanoscale ultrafine powder materials.

[0007] The refining agent provided in this application possesses high-temperature resistance and chemical inertness. It will not melt in the high-temperature environment of powder material preparation, providing stable seed crystals. Its chemical inertness ensures that no chemical reactions occur during the preparation process or in the finished material, thus preventing any impact on the performance of the powder material. Furthermore, the refining agent provided in this embodiment facilitates processing into ultrafine powders at the nanoscale, such as below 50 nm, which is beneficial for effectively refining the powder material.

[0008] In addition, the refining agent provided in this application is easy to obtain and has virtually no corrosive effect on equipment.

[0009] In some embodiments of this application, at least one of the following is satisfied: (i) The refining agent includes at least one of silicon and silicon dioxide; (ii) Raw materials include: a combination of silicon and aluminum.

[0010] In some embodiments of this application, the amount of the refining agent added is 0.5% to 1% of the mass of the raw material; and / or, the average particle size of the refining agent is 5 nm to 20 nm.

[0011] In some embodiments of this application, the raw material is a combination of silicon and aluminum, with the silicon content being 10% to 50% by mass.

[0012] The second aspect of this application discloses a method for preparing a powder material, comprising the steps of: The raw materials are heat-treated to obtain a melt; the raw materials include: silicon; or, a combination of silicon and aluminum; The melt is mixed with a refining agent to obtain a mixture; the refining agent includes at least one selected from silicon, aluminum oxide, cerium oxide, titanium dioxide, lanthanum oxide, silicon dioxide, zirconium dioxide, nickel oxide, iron oxide, silver, aluminum, and iron; the amount of refining agent added is 0.01% to 2% of the mass of the raw material; The mixture is cooled to obtain a powder material.

[0013] The powder material preparation method provided in this application uses a new refining agent, which is used in combination with silicon-containing raw materials to achieve a good refining effect on silicon-containing materials.

[0014] This application provides a method for preparing powder materials, using silicon-containing materials as raw materials, specifically two types: one is silicon; the other is a combination of silicon and aluminum. When preparing powder materials using the above raw materials, during the heating process to prepare the melt, the silicon in the raw materials first precipitates out and becomes solid. By adding a grain refiner, which mainly acts on the silicon, it can serve as a nucleation site for the precipitated silicon, promoting the refinement of silicon grains and obtaining nanoscale ultrafine powder materials.

[0015] The refining agent used in the preparation method provided in this application has the characteristics of high temperature resistance and chemical inertness. It will not melt in the high-temperature environment of powder material preparation, providing stable seed crystals. Its chemical inertness ensures that no chemical reaction occurs during the preparation process or in the finished material, thus preventing any impact on the performance of the powder material. Furthermore, the refining agent provided in this embodiment facilitates processing into nanoscale ultrafine powders, such as those below 50 nm, which is beneficial for effectively refining the powder material.

[0016] Furthermore, the refining agent used in the preparation method provided in this application is relatively easy to obtain and has virtually no corrosive effect on equipment.

[0017] In some embodiments of this application, at least one of the following is satisfied: (i) The refining agent includes at least one of silicon and silicon dioxide; (ii) Raw materials include: a combination of silicon and aluminum.

[0018] In some embodiments of this application, the amount of the refining agent added is 0.5% to 1% of the mass of the raw material; and / or, the average particle size of the refining agent is 5 nm to 20 nm.

[0019] In some embodiments of this application, the raw material is a combination of silicon and aluminum, with the silicon content being 10% to 50% by mass.

[0020] In some embodiments of this application, the D50 of the powder material is 20 μm to 40 μm, and / or the grain size of the powder material is less than 70 nm.

[0021] In some embodiments of this application, the preparation method satisfies at least one of the following: (i) In the step of heat treating the raw materials, the controlled parameters include: temperature of 680 ℃~1200 ℃; (ii) In the step of heat treating the raw materials, the heat treatment temperature is within 150 °C higher than the melting temperature of the raw materials; (iii) In the step of mixing the melt with the refining agent, the temperature after mixing is maintained at the heat treatment temperature, and the holding time is 10 min to 5 h.

[0022] A third aspect of this application provides an electrode material, the raw materials of which include the powder material described above, or the powder material prepared by the preparation method described above.

[0023] The electrode material provided in this application is prepared from the powder material described above, or from the powder material prepared by the method described above. The powder material has a small grain size and small particle diameter, which is beneficial for obtaining electrodes with good electrical performance. Specifically, for example, a smaller grain size can increase the specific surface area of ​​the material, thereby increasing the contact area with the electrolyte, which helps to improve the charge / discharge efficiency and rate capability of the battery. Furthermore, fine grains can reduce volume expansion and contraction during charge and discharge, thereby improving the structural stability and cycle life of the negative electrode material.

[0024] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 The image shows a TEM image of the powder material obtained in Example 1 of this application, with a scale bar of 20 nm.

[0026] Figure 2 The image shows a TEM image of the powder material obtained in Example 1 of this application, with a scale bar of 50 μm. Detailed Implementation

[0027] The embodiments of this application are described in detail below. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0028] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more.

[0029] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this application.

[0030] In this application, the terms "comprising" or "including" are open-ended expressions, meaning they include the content specified in this application but do not exclude other aspects.

[0031] Grain size has a significant impact on the performance of powder materials. Taking alloy powder as an example, at room temperature, the smaller the grain size, the higher the strength and hardness of the metal, and the better its plasticity and toughness. Currently, common methods for refining grain size include: (1) increasing the degree of supercooling; (2) grain refining treatment; and (3) vibration treatment. Among these, the grain refining treatment mainly involves adding a certain chemical element or compound (modifier) ​​to the liquid metal. Commonly used grain refining agents include titanium bulk agents, salt-based grain refining agents, and intermediate alloy-type grain refining agents. These grain refining agents have the problem of being difficult to synthesize. In addition, for example, phosphorus-containing grain refining agents cause significant corrosion to equipment. Therefore, developing suitable grain refining agents is of great significance for the preparation of high-performance alloy powders. For this purpose, the embodiments of this application use a new grain refining agent for silicon-containing powders, which can replace the original grain refining agent, as shown below.

[0032] The first aspect of this application provides a powder material, including raw materials and a refining agent; The refining agent includes at least one of silicon, aluminum oxide, cerium oxide, titanium dioxide, lanthanum oxide, silicon dioxide, zirconium dioxide, nickel oxide, iron oxide, silver, aluminum, and iron; The raw materials include: silicon; or a combination of silicon and aluminum; The amount of finer agent added is 0.01% to 2% of the mass of the raw material.

[0033] The powder material proposed in this application uses silicon-containing materials as raw materials, specifically two types: one is silicon; the other is a combination of silicon and aluminum. When preparing the powder material using the above raw materials, during the heating process to prepare the melt, the silicon in the raw materials first precipitates out and becomes solid. By adding a grain refiner, which mainly acts on the silicon, it can serve as a nucleation site for the precipitated silicon, promoting the refinement of silicon grains and obtaining nanoscale ultrafine powder materials.

[0034] The refining agent provided in this application has the characteristics of high temperature resistance and chemical inertness. It will not melt in the high-temperature environment of powder material preparation, providing stable seed crystals. Moreover, its chemical inertness ensures that no chemical reaction will occur during the preparation process or in the finished material, thus affecting the performance of the powder material. Furthermore, the refining agent provided in this embodiment is easy to process into nanoscale ultrafine powders, such as those below 50 nm, which is beneficial for effectively refining the powder material.

[0035] In this embodiment, the amount of refining agent added meets the above conditions, which is beneficial for promoting the refinement of powder materials and ensuring low production costs. If too little refining agent is added, the number of nucleation sites will be small, and the grain size of the resulting powder material will be larger; if too much refining agent is added, other refining agents besides silicon will lead to an increase in the impurity content or oxygen content in the material, and the use of large amounts of nano-silicon in high-temperature environments can easily lead to safety issues and excessively high usage costs. In specific examples, the amount of refining agent added is 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2% of the raw material mass, etc.

[0036] Furthermore, the refining agent provided in this application embodiment is relatively easy to obtain and has virtually no corrosive effect on the equipment.

[0037] In some embodiments of this application, the refining agent includes at least one of silicon, silicon dioxide, aluminum oxide, and zirconium oxide.

[0038] In this embodiment, at least one of silicon, silicon dioxide, aluminum oxide and zirconium oxide is selected as a grain refiner for silicon-containing powder materials, which is beneficial to promote grain refinement of powder materials and obtain powder materials with small grain size and small particle size.

[0039] In some embodiments of this application, in the combination of silicon and aluminum, the mass percentage of silicon is 10% to 50% of the total mass of the combination.

[0040] In this embodiment, the silicon content meets the above conditions. Using the above raw materials to prepare powder materials, heating the raw materials to prepare a melt helps maintain a low viscosity, thus ensuring good heat dissipation during cooling and preventing excessively large grains. Specifically, the silicon mass percentage is 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50% of the total combined mass.

[0041] In some embodiments of this application, in the combination of silicon with at least one of aluminum, magnesium, iron, calcium, cobalt, nickel, copper, zinc, tin and phosphorus, the mass percentage of silicon is 20% to 30% of the total mass of the combination.

[0042] In the embodiments of this application, the silicon content meets the above conditions, which is beneficial for forming powder materials with smaller grains. In specific examples, the mass percentage of silicon is 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30% of the total mass of the combination, etc.

[0043] In some embodiments of this application, the D50 of the powder material is 20 μm to 40 μm, and / or the grain size of the powder material is less than 70 nm.

[0044] The embodiments of this application employ a grain refiner and control its dosage, which can serve as nucleation sites for precipitated silicon, promoting silicon grain refinement and yielding nanoscale ultrafine powder materials.

[0045] As an example, the D50 of the powder material is 20 μm, 22 μm, 24 μm, 26 μm, 28 μm, 30 μm, 32 μm, 34 μm, 36 μm, 38 μm, 40 μm, etc.

[0046] As an example, the grain size of the powder material is 70 nm, 65 nm, 60 nm, 55 nm, 50 nm, 45 nm, 40 nm, 35 nm, 30 nm, 25 nm, 20 nm, 15 nm, 10 nm, etc.

[0047] In some embodiments of this application, at least one of the following is satisfied: (i) The refining agent includes at least one of silicon and silicon dioxide; (ii) Raw materials include: a combination of silicon and aluminum.

[0048] In this embodiment, at least one of silicon and silicon dioxide is used as a refining agent. Furthermore, silicon is used as the refining agent because it possesses high-temperature resistance and chemical inertness. It will not melt in the high-temperature environment of powder material preparation, providing stable seed crystals. Its chemical inertness ensures that no chemical reactions occur during the preparation process or in the finished material, thus preventing any impact on the performance of the powder material. Moreover, the refining agent provided in this embodiment facilitates processing into nanoscale ultrafine powders, such as those below 50 nm, which is beneficial for effectively refining the powder material. In addition, silicon, in particular, as a refining agent, can reduce the introduction of impurities, avoiding contamination of the powder material and preventing any impact on its performance.

[0049] In this embodiment, the raw materials used are a combination of silicon and aluminum.

[0050] Using a combination of silicon and aluminum as raw materials, with aluminum as the base material, the silicon and aluminum alloy phases are simple, with clear distinction between the silicon and aluminum phases, making it difficult to form other aluminum-silicon compounds; and the effect is better when used in combination with refining agents, resulting in smaller crystal grain size and smaller powder particles.

[0051] In some embodiments of this application, the amount of the refining agent added is 0.5% to 1% of the mass of the raw material; and / or, the average particle size of the refining agent is 5 nm to 20 nm.

[0052] In this embodiment, the amount of refining agent added meets the above conditions, which can effectively refine the powder material and ensure low production costs. In specific examples, the amount of refining agent added is 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1% of the mass of the raw material, etc.

[0053] In this embodiment, the average particle size of the grain refiner meets the above conditions; the smaller the particle size of the grain refiner, the more beneficial it is for refining the raw material grains. Simultaneously, it avoids increasing the preparation and storage costs of the grain refiner, and prevents problems such as agglomeration and diffusion difficulties when the grain refiner with excessively small particle size is added to the melt. For example, if nano-silicon with excessively small particle size has high activity, it may actually increase the difficulty of production. In specific examples, the average particle size of the grain refiner is 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, etc.

[0054] In some embodiments of this application, the average particle size of the refining agent is 5 nm to 15 nm.

[0055] In this embodiment, the average particle size of the refining agent meets the above conditions, which is beneficial to achieve effective refining of powder materials and avoids increasing production difficulty.

[0056] In some embodiments of this application, the raw material is a combination of silicon and aluminum, with the silicon content being 10% to 50% by mass.

[0057] In this embodiment, the silicon content meets the above conditions. Using the above raw materials to prepare powder materials, heating the raw materials to prepare a melt helps maintain a low viscosity, thus ensuring good heat dissipation during cooling and preventing excessively large grains. Specifically, the silicon mass percentage is 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50% of the total combined mass.

[0058] In some embodiments of this application, in the combination of silicon and aluminum, the mass percentage of silicon is 20% to 30% of the total mass of the combination.

[0059] In the embodiments of this application, the silicon content meets the above conditions, which is beneficial for forming powder materials with smaller grains. In specific examples, the mass percentage of silicon is 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30% of the total mass of the combination, etc.

[0060] The second aspect of this application provides a method for preparing a powder material, including the following steps: The raw materials are heat-treated to obtain a melt; the raw materials include: silicon; or, a combination of at least one of silicon and aluminum; The melt is mixed with a refining agent to obtain a mixture; the refining agent includes at least one selected from silicon, aluminum oxide, cerium oxide, titanium dioxide, lanthanum oxide, silicon dioxide, zirconium dioxide, nickel oxide, iron oxide, silver, aluminum, and iron; the amount of refining agent added is 0.01% to 2% of the mass of the raw material; The mixture is cooled to obtain a powder material.

[0061] The powder material preparation method provided in this application uses a new refining agent, which is used in combination with silicon-containing raw materials to achieve a good refining effect on silicon-containing materials.

[0062] This application provides a method for preparing powder materials, using silicon-containing materials as raw materials, specifically two types: one is silicon; the other is a combination of silicon and aluminum. When preparing powder materials using the above raw materials, during the heating process to prepare the melt, the silicon in the raw materials first precipitates out and becomes solid. By adding a grain refiner, which mainly acts on the silicon, it can serve as a nucleation site for the precipitated silicon, promoting the refinement of silicon grains and obtaining nanoscale ultrafine powder materials.

[0063] The refining agent used in the preparation method provided in this application has the characteristics of high temperature resistance and chemical inertness. It will not melt in the high-temperature environment of powder material preparation, providing stable seed crystals. Its chemical inertness ensures that no chemical reaction occurs during the preparation process or in the finished material, thus preventing any impact on the performance of the powder material. Furthermore, the refining agent provided in this embodiment facilitates processing into nanoscale ultrafine powders, such as those below 50 nm, which is beneficial for effectively refining the powder material.

[0064] In this embodiment, the amount of refining agent added meets the above conditions, which is beneficial for promoting the refinement of powder materials and ensuring low production costs. If too little refining agent is added, the number of nucleation sites will be small, and the grain size of the resulting powder material will be larger; if too much refining agent is added, other refining agents besides silicon will lead to an increase in the impurity content or oxygen content in the material, and the use of large amounts of nano-silicon in high-temperature environments can easily lead to safety issues and excessively high usage costs. In specific examples, the amount of refining agent added is 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2% of the raw material mass, etc.

[0065] Furthermore, the refining agent used in the preparation method provided in this application is relatively easy to obtain and has virtually no corrosive effect on equipment.

[0066] In some embodiments of this application, at least one of the following is satisfied: (i) The refining agent includes at least one of silicon and silicon dioxide; (ii) Raw materials include: a combination of silicon and aluminum.

[0067] In this embodiment, at least one of silicon and silicon dioxide is used as a refining agent, and more specifically, silicon is used. Silicon possesses high-temperature resistance and chemical inertness, meaning it will not melt in the high-temperature environment of powder material preparation, providing stable seed crystals. Its chemical inertness ensures that no chemical reactions occur during the preparation process or in the finished material, thus preventing any impact on the performance of the powder material. Furthermore, the refining agent provided in this embodiment facilitates processing into ultrafine powders at the nanoscale, such as below 50 nm, which is beneficial for effectively refining the powder material. In addition, silicon, in particular, as a refining agent, can reduce the introduction of impurities, avoiding contamination of the powder material and preventing any impact on its performance.

[0068] In this embodiment, the raw materials used are a combination of silicon and aluminum.

[0069] Using a combination of silicon and aluminum as raw materials, with aluminum as the base material, the silicon-aluminum alloy phase is simple, with clear distinction between the silicon and aluminum phases, making it difficult to form other aluminum-silicon compounds; and the effect is better when used in combination with refining agents, resulting in smaller crystal grain size, smaller powder particles, and very small silicon particles.

[0070] In some embodiments of this application, the amount of the refining agent added is 0.5% to 1% of the mass of the raw material; and / or, the average particle size of the refining agent is 5 nm to 20 nm.

[0071] In this embodiment, the amount of refining agent added meets the above conditions, which can effectively refine the powder material and ensure low production costs. In specific examples, the amount of refining agent added is 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1% of the mass of the raw material, etc.

[0072] In this embodiment, the average particle size of the grain refiner meets the above conditions; the smaller the particle size of the grain refiner, the more beneficial it is for refining the raw material grains. Simultaneously, it avoids increasing the preparation and storage costs of the grain refiner, and prevents problems such as agglomeration and diffusion difficulties when the grain refiner with excessively small particle size is added to the melt. For example, if nano-silicon with excessively small particle size has high activity, it may actually increase the difficulty of production. In specific examples, the average particle size of the grain refiner is 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, etc.

[0073] In some embodiments of this application, the average particle size of the refining agent is 5 nm to 15 nm.

[0074] In this embodiment, the average particle size of the refining agent meets the above conditions, which is beneficial to achieve effective refining of powder materials and avoids increasing production difficulty.

[0075] In some embodiments of this application, the raw material is a combination of silicon and aluminum, with the silicon content being 10% to 50% by mass.

[0076] In this embodiment, the silicon content meets the above conditions. Using the above raw materials to prepare powder materials, heating the raw materials to prepare a melt helps maintain a low viscosity, thus ensuring good heat dissipation during cooling and preventing excessively large grains. Specifically, the silicon mass percentage is 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50% of the total combined mass.

[0077] In some embodiments of this application, in the combination of silicon and aluminum, the mass percentage of silicon is 20% to 30% of the total mass of the combination.

[0078] In the embodiments of this application, the silicon content meets the above conditions, which is beneficial for forming powder materials with smaller grains. In specific examples, the mass percentage of silicon is 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30% of the total mass of the combination, etc.

[0079] In some embodiments of this application, the preparation method satisfies at least one of the following: (i) In the step of heat treating the raw materials, the controlled parameters include: temperature of 680 ℃~1200 ℃; (ii) In the step of heat treating the raw materials, the heat treatment temperature is within 150 °C higher than the melting temperature of the raw materials; (iii) In the step of mixing the melt with the refining agent, the temperature after mixing is maintained at the heat treatment temperature, and the holding time is 10 min to 5 h.

[0080] In this embodiment of the application, in the step of heat treatment of raw materials, based on the melting phase diagram of silicon-aluminum alloy, the temperature is controlled at 680 ℃~1200 ℃, which can realize the heat treatment of silicon and aluminum combined raw materials to at least partially melted state. In a specific example, the controlled temperatures are 680℃, 700℃, 710℃, 720℃, 730℃, 740℃, 750℃, 760℃, 770℃, 780℃, 790℃, 800℃, 810℃, 820℃, 830℃, 840℃, 850℃, 860℃, 870℃, 880℃, 890℃, 900℃, 910℃, 920℃, 930℃, 940℃, 950℃, 960℃, 970℃, 980℃, 990℃, 1000℃, 1010℃, 1020℃, 1030℃, 1040℃, 1050℃, 1060℃, and 1070℃. ℃, 1080 ℃, 1090 ℃, 1100 ℃, 1200 ℃, etc.

[0081] In this embodiment, the heat treatment temperature is controlled to be within 150°C above the melting temperature of the raw material. This ensures the raw material is fully melted and avoids the heat treatment temperature being too high above the melting temperature, which would prolong the cooling time and cause grain growth; it would also increase costs. Specifically, the heat treatment temperature is controlled to be 150°C, 140°C, 130°C, 120°C, 110°C, 100°C, 90°C, 80°C, 70°C, 60°C, 50°C, 40°C, 30°C, 20°C, etc., above the melting temperature of the raw material. Further, the heat treatment temperature is controlled to be 100°C to 150°C above the melting temperature of the raw material.

[0082] In this embodiment, after the grain refiner is added to the melt, it is maintained at a temperature that prevents the melt from solidifying for 10 min to 5 h. This promotes full contact between the powdered grain refiner and the melt, resulting in uniform grain growth while maintaining high production efficiency. Specific examples show maintenance times of 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, and 5 h.

[0083] Furthermore, in the step of mixing the melt with the refining agent, the temperature after mixing is maintained at the heat treatment temperature, i.e., 700 ℃~1100 ℃, and the holding time is 30 min~120 min. In specific examples, the holding times are 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, 95 min, 100 min, 105 min, 110 min, 115 min, 120 min, etc.

[0084] In some embodiments of this application, the cooling method used in the step of cooling the mixture includes air atomization, water atomization, or centrifugal atomization.

[0085] Furthermore, the cooling gas medium for gas atomization includes an inert gas, such as nitrogen or argon, and even further, the cooling gas medium for gas atomization is nitrogen.

[0086] Furthermore, the airflow sweep velocity of the atomized cooling gas medium is greater than 10 m / s. 3 / min.

[0087] Furthermore, the cooling method employed is gas atomization. Gas atomization is less likely to cause material oxidation, and the cooling process can be controlled by adjusting the airflow speed and flow rate, offering strong controllability and facilitating the acquisition of finer powder materials.

[0088] In some embodiments of this application, the method for preparing the powder material includes the following steps: S1000. The raw material is heat-treated to obtain a melt. The raw material includes silicon; or a combination of silicon and aluminum. Specifically, the raw material can be placed in a heating furnace and heated to a set temperature to a molten state.

[0089] S2000. The melt is mixed with a grain refiner to obtain a mixture; the grain refiner includes at least one of silicon, aluminum oxide, cerium oxide, titanium dioxide, lanthanum oxide, silicon dioxide, zirconium dioxide, nickel oxide, iron oxide, silver, aluminum, and iron. The grain refiner is added to the melt, and the above temperature is maintained for a certain period of time until the mixture is uniform and the grains grow uniformly before proceeding to the next step.

[0090] S3000. Cool the mixture to obtain a powder material. Use a cooling device to cool the melt into a powder material.

[0091] A third aspect of this application provides an electrode material, the raw materials of which include the powder material described above, or the powder material prepared by the preparation method described above.

[0092] The electrode material provided in this application embodiment is prepared from the powder material described above, or from the powder material prepared by the method described above. The powder material has a small grain size and small particle size, which is beneficial for obtaining an electrode with good electrical performance. Specifically, for example, a smaller grain size can increase the specific surface area of ​​the material, thereby increasing the contact area with the electrolyte, which helps to improve the charge and discharge efficiency and rate capability of the battery. In addition, fine grains can reduce volume expansion and contraction during charge and discharge, thereby improving the structural stability and cycle life of the negative electrode material.

[0093] In some embodiments of this application, the electrode material is a negative electrode active material. Specifically, silicon-aluminum alloy powder material, as a negative electrode active material, does indeed play a role in lithium-ion batteries in both lithium delithiation and lithium intercalation.

[0094] It should be noted that the features and advantages described above regarding the preparation methods of the powder materials in the first and second aspects of this application also apply to the electrode materials in the third aspect of this application, and will not be repeated here.

[0095] The following will explain the solution of this application with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0096] Example 1 The preparation method of powder materials is as follows: Step 1: In a nitrogen atmosphere, aluminum ingots and silicon ingots (both commercially available) with a mass ratio of 4:1 are placed in a medium-frequency induction furnace, i.e., the silicon and aluminum combination raw materials have a silicon mass percentage of 20%, and heated to 800 ℃ to a molten state to obtain a melt.

[0097] Step 2: Add 0.5% of the raw material mass of the refining agent (silicon powder with an average particle size of 10 nm) to the melt obtained in Step 1, stir and mix evenly, and keep at the heating temperature of Step 1 for 1 h to obtain the melt (the refining agent remains solid).

[0098] Step 3: In the atomization equipment (using the experimental atomization powder making equipment from Zhuzhou Shuangling Technology Co., Ltd.), nitrogen is used as the cooling gas medium, and the airflow purging velocity is 12 m / s. 3 / min, the molten metal is blown into metal powder.

[0099] Example 2-Example 32 The powder materials in Examples 2-32 were prepared using the same method as in Example 1. The specific composition, dosage, and parameters are shown in Table 1.

[0100] Comparative Examples 1-5 The powder materials in Comparative Examples 1-5 were prepared using the method described in Example 1. The specific composition, dosage, and parameters are shown in Table 1.

[0101]

[0102] Note: The refining agents used in Comparative Examples 1-3 in Table 1 are shown below: Titanium-boron composite modifier: Sichuan Lande High-Tech Industry Co., Ltd., titanium-boron refining agent AX201.

[0103] Phosphate salt composite modifier: Xuzhou Siyuan Aluminum Co., Ltd., phosphate salt composite modifier, SY-PB1.

[0104] Aluminum-copper alloy modifier: Sichuan Lande High-Tech Industry Co., Ltd., copper additive - Cu75.

[0105] Performance testing I. Testing Method: 1. Particle size D of powder material 50 (D) 50 This refers to the particle size corresponding to a cumulative particle size distribution percentage of 50% for a sample: measured using a particle size analyzer, the equipment automatically outputs D. 50 size.

[0106] 2. Powder material grain size: In-situ transmission electron microscopy was used for characterization and analysis of particle size.

[0107] II. Test Results: The performance test results of Examples 1-32 and Comparative Examples 1-5 are shown in Table 2.

[0108]

[0109] The refining agent provided in this embodiment facilitates the processing of nanoscale ultrafine alloy powders, and the grain size can reach below 70 nm, which is beneficial for effectively refining powder materials.

[0110] As shown in Table 2, in the embodiments of this application, the amount of refining agent added meets the above conditions, which is beneficial to promoting the refining of powder materials and ensuring low production costs. If too little refining agent is added, the number of nucleation sites will be small, and the grain size of the powder material will become larger; if too much refining agent is added, other refining agents besides silicon will cause the impurity content or oxygen content in the material to increase, and the use of a large amount of nanoscale refining agent (i.e., nano-silicon) in a high-temperature environment is prone to safety problems and excessively high usage costs.

[0111] like Figure 1 and Figure 2 As shown, the addition of a silicon refiner during the preparation of silicon-aluminum alloy powder materials results in smaller grain sizes. Figure 1 As shown), and the particle size of the powder is relatively small ( Figure 2 As shown in the figure, it effectively achieves the effect of refining powder materials.

[0112] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A powder material, characterized in that, Including raw materials and refining agents; The refining agent includes at least one of elemental silicon and silicon dioxide; The raw materials include a combination of silicon and aluminum, wherein the silicon content is 10% to 50% by mass. The amount of the refining agent added is 0.01% to 2% of the mass of the raw material; The grain size of the powder material is below 70 nm.

2. The powder material according to claim 1, characterized in that, The amount of the refining agent added is 0.5% to 1% of the mass of the raw material; and / or, the average particle size of the refining agent is 5 nm to 20 nm.

3. The powder material according to claim 1, characterized in that, The D50 of the powder material is 20 μm to 40 μm.

4. A method for preparing a powder material, characterized in that, Including the following steps: The raw materials are heat-treated to obtain a melt; the raw materials include a combination of silicon and aluminum, with the silicon content ranging from 10% to 50% by mass. The melt is mixed with a refining agent to obtain a mixture; the refining agent includes at least one of elemental silicon and silicon dioxide; the amount of the refining agent added is 0.01% to 2% of the mass of the raw material; The mixture is cooled to obtain a powder material with a grain size of less than 70 nm.

5. The method for preparing powder material according to claim 4, characterized in that, The amount of the refining agent added is 0.5% to 1% of the mass of the raw material; and / or, the average particle size of the refining agent is 5 nm to 20 nm.

6. The method for preparing powder material according to claim 4, characterized in that, The preparation method satisfies at least one of the following: (i) In the step of heat treating the raw materials, the control parameters include: the temperature is 680 ℃~1200 ℃; (ii) In the step of heat treating the raw material, the heat treatment temperature is within 150 °C higher than the melting temperature of the raw material; (iii) In the step of mixing the melt with the refining agent, the temperature after mixing is maintained at the temperature of heat treatment, and the holding time is 10 min to 5 h.

7. An electrode material, characterized in that, The raw materials include the powder material as described in any one of claims 1 to 3, or the powder material prepared by the preparation method as described in any one of claims 4 to 6.

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