Processing technology of negative material of fast charge-discharge lithium battery

Abstract

This application relates to the field of battery material preparation, specifically disclosing a processing technology for a fast-charging and discharging lithium battery anode material, including the following steps: S1, weighing natural graphite and crushing it to obtain natural graphite flakes; the natural graphite flakes are then subjected to ultra-fine crushing to obtain natural graphite particles; the natural graphite particles are then subjected to surface treatment to obtain natural graphite powder; S2, the natural graphite powder and asphalt powder are mixed and stirred evenly, with the asphalt powder accounting for 10-15% of the weight of the natural graphite powder, and after granulation, shaping, graphitization, deagglomeration, sieving, and demagnetization, the finished anode material is obtained; it has the advantages of fast charging and discharging capacity and high charging and discharging efficiency.

Description

Technical Field

[0001] This application relates to the field of battery material preparation, and more specifically, it relates to a processing technology for a fast-charging and discharging lithium battery anode material. Background Technology

[0002] The negative electrode materials in lithium-ion batteries can be graphite-based materials, non-graphite carbon materials, silicon-based materials, silicon suboxide materials, tin-based materials, titanium-based materials, etc.

[0003] Graphite materials have advantages such as low lithium potential, high initial efficiency, good cycle stability, and low cost, making them a commonly used anode material for lithium batteries. Graphite is mainly divided into natural graphite and artificial graphite. Natural graphite often needs to be modified to improve its electrochemical performance due to problems such as many surface defects, large specific surface area, and low initial efficiency.

[0004] Therefore, how to prepare a new anode material that has both fast charge and discharge capacity and high charge and discharge efficiency is a problem that needs to be solved. Summary of the Invention

[0005] In order to prepare a new anode material that has both fast charge and discharge capacity and high charge and discharge efficiency, this application provides a processing technology for a fast charge and discharge lithium battery anode material.

[0006] This application provides a processing technology for a fast-charging and discharging lithium battery negative electrode material, which adopts the following technical solution:

[0007] A processing technology for a fast-charging and discharging lithium battery anode material includes the following steps:

[0008] S1. Weigh natural graphite and crush it to obtain natural graphite flakes; crush the natural graphite flakes into natural graphite particles; and surface treat the natural graphite particles to obtain natural graphite powder.

[0009] S2. Natural graphite powder and asphalt powder are mixed and stirred evenly, with the weight of asphalt powder accounting for 10-15% of the weight of natural graphite powder. After granulation, shaping, graphitization, deagglomeration, sieving, and demagnetization, the finished negative electrode material is obtained.

[0010] By adopting the above technical solution, natural graphite is crushed to obtain natural graphite flakes with relatively uniform particle size, so as to ensure that the natural graphite flakes are uniformly crushed by ultra-fine crushing. After ultra-fine crushing, more micro-scratches and micro-channels are generated on the surface of the natural graphite flakes. Combined with the micro-gaps on the surface of the asphalt powder and the limited amount of asphalt powder added, the surface of the negative electrode material forms multi-directional interconnected channels, which can not only improve the charging and discharging efficiency, but also improve the charging and discharging capacity, so that the finished negative electrode material has a faster charging and discharging speed.

[0011] Preferably, the crushing process in S1 is layered crushing. After the first crushing, the material is passed through an 8-15 mesh sieve, and then the material on the sieve is crushed a second time until it all passes through an 8-15 mesh sieve.

[0012] By adopting the above technical solution, which involves two crushing and screening processes, the particle size of natural graphite flakes can be kept relatively uniform. This prevents the simultaneous ultrafine crushing of small-diameter powder and large-diameter particles. If small-diameter and large-diameter particles coexist, the particle size of the ultrafine crushed products will also be uneven, which will not only reduce the utilization rate of raw materials but also easily affect the charging and discharging efficiency of the negative electrode material.

[0013] Preferably, the natural graphite flakes are subjected to ultrafine crushing once to a particle size of 20-50 μm, then dispersed and stirred in a hydrogen peroxide solution, the particles are filtered out and washed with water, then treated with ozone oxidation, and finally ultrafine crushed again to a particle size of 2-5 μm.

[0014] By adopting the above technical solution, after the natural graphite flakes are first ultra-finely crushed, they are then oxidized with hydrogen peroxide solution. After oxidation, hydroxyl groups and other groups exist between the layers of natural graphite flakes, which facilitates the contact and bonding of natural graphite powder and asphalt, and increases the interlayer spacing. Then, ozone oxidation treatment is carried out to further increase the interlayer spacing, thereby facilitating the deposition of asphalt powder on the surface and inside of natural graphite powder, making the flake graphite tend to have a spherical structure. As a result, the negative electrode material has a high density, high charge and discharge efficiency, and large capacity.

[0015] Preferably, the hydrogen peroxide solution is composed of hydrogen peroxide and silicon dioxide in a weight ratio of 1:0.1-0.3.

[0016] By adopting the above technical solution, hydrogen peroxide and silicon dioxide are combined. When natural graphite sheets are dispersed and stirred in a hydrogen peroxide solution, the hydrogen peroxide oxidizes the graphite while stirring, and the high strength of silicon dioxide causes the silicon dioxide to create slits on the surface of the natural graphite sheets. The creation of slits not only improves the crushing efficiency of ultrafine crushing, but also improves the multidirectionality of electron channels, thereby improving the charging and discharging speed and charging and discharging efficiency of the finished negative electrode material.

[0017] Preferably, the silica is composed of silica microspheres, polyurethane liquid and silica whiskers in a weight ratio of 1:0.05-0.2:0.1-0.4.

[0018] By adopting the above technical solution, silica microspheres, polyurethane liquid, and silica whiskers are combined. The viscosity of the polyurethane liquid facilitates the adhesion of silica whiskers to the surface of silica microspheres. The spherical microparticles carry needle-like whiskers. During the stirring process, the toughness of the polyurethane makes the silica whiskers relatively stable on the surface of silica microspheres. Furthermore, the large specific surface area of ​​silica microspheres, combined with the needle-like structure of silica, makes it easy to scratch the surface of natural graphite flakes, thereby creating more micro-gaps. This not only facilitates the crushing of natural graphite flakes to a particle size of 3-5μm, but the presence of micro-gaps also improves the charging and discharging efficiency.

[0019] Both silica and polyurethane are resistant to hydrogen peroxide and do not readily react with hydrogen peroxide. This allows natural graphite sheets to improve interlayer spacing through oxidation during the hydrogen peroxide treatment, while also creating scratches and deeper grooves on the surface of the natural graphite sheets. When natural graphite powder comes into contact with asphalt powder, it facilitates the deposition of asphalt powder on the surface and in the layer structure of the natural graphite powder, thereby increasing the density of the finished negative electrode material and improving the charge and discharge efficiency.

[0020] Preferably, the surface treatment involves mixing and stirring natural graphite particles with abrasive materials, wherein the weight ratio of natural graphite particles to abrasive materials is 1:1-2.

[0021] By adopting the above technical solution, natural graphite particles and abrasives are combined, and the abrasives are used to scratch the surface of the natural graphite particles, so that more microchannels are generated on the surface of the natural graphite particles. By utilizing the multidirectional electron channels, the charge and discharge efficiency and charge and discharge capacity of the finished negative electrode material are improved.

[0022] Preferably, the abrasive is prepared by loading polyurethane liquid and tetra-needle zinc oxide whiskers sequentially with silicon carbide whiskers in a weight ratio of 1:0.2-0.5:1-2.

[0023] By adopting the above technical solution, silicon carbide whiskers, polyurethane liquid, and tetrapter zinc oxide whiskers are combined. The viscosity of the polyurethane liquid allows the tetrapter zinc oxide whiskers to be loaded onto the surface of the silicon carbide whiskers. The spiky structure of the silicon carbide whiskers, combined with the four-sided spiky structure of the tetrapter zinc oxide whiskers, further scratches the small-sized natural graphite particles, thereby creating multi-directional channels on the surface of the natural graphite powder, improving the charging and discharging speed and efficiency.

[0024] Both silicon carbide whiskers and tetra-needle zinc oxide whiskers have high strength, ensuring that the abrasive can scratch the natural graphite flakes. Moreover, by utilizing the toughness and viscosity of polyurethane, the abrasive can scratch the natural graphite particles while minimizing the dispersion of silicon carbide whiskers and tetra-needle zinc oxide whiskers. This improves the charge and discharge efficiency of the finished negative electrode material and allows the abrasive to be reused.

[0025] Preferably, the abrasive particle size is 10-20 μm.

[0026] By adopting the above technical solution, the particle size of the abrasive is larger than that of the graphite powder, thus facilitating separation.

[0027] Preferably, the asphalt powder is ultra-finely crushed to a particle size of 3-5 μm.

[0028] By adopting the above technical solution, the ultrafine particle size of asphalt can not only make uniform contact with natural graphite powder, but also further realize the multidirectional function of electron channels during the deposition process, thereby improving the charging and discharging speed and charging and discharging efficiency.

[0029] Preferably, the graphitization temperature is 2400-2550℃.

[0030] By adopting the above technical solution, the graphitization treatment temperature of 2400-2500℃ is lower than the existing graphitization treatment temperature of 3000℃. This not only improves the yield but also ensures the graphitization deposition effect of the asphalt. After deposition, it can ensure the multidirectional nature of the electron channels, improve the charging and discharging efficiency, and increase the tap density. This gives the negative electrode material processing process the advantages of high yield and simple processing.

[0031] In summary, this application has the following beneficial effects:

[0032] 1. After being crushed, natural graphite is made into natural graphite flakes with relatively uniform particle size to ensure that the natural graphite flakes are uniformly crushed by ultra-fine crushing. After ultra-fine crushing, more micro-scratches and micro-channels are generated on the surface of the natural graphite flakes. Combined with the micro-gaps on the surface of the asphalt powder and the limited amount of asphalt powder added, the surface of the negative electrode material forms multi-directional interconnected channels, which can not only improve the charging and discharging efficiency, but also improve the charging and discharging capacity, so that the finished negative electrode material has a faster charging and discharging speed.

[0033] 2. The combination of silica microspheres, polyurethane liquid, and silica whiskers utilizes the viscosity of the polyurethane liquid to facilitate the adhesion of silica whiskers to the surface of silica microspheres. The spherical microparticles support needle-like whiskers. During stirring, the large specific surface area of ​​the silica microspheres, combined with the needle-like structure of silica, facilitates scratching the surface of natural graphite flakes, thereby creating more micro-gaps. This not only facilitates the crushing of natural graphite flakes to a particle size of 3-5μm, but the presence of micro-gaps also improves the charging and discharging efficiency.

[0034] 3. Silicon carbide whiskers, polyurethane liquid, and tetrapter zinc oxide whiskers are combined. The viscosity of the polyurethane liquid allows the tetrapter zinc oxide whiskers to be loaded onto the surface of the silicon carbide whiskers. The spiky structure of the silicon carbide whiskers, combined with the four-sided spiky structure of the tetrapter zinc oxide whiskers, further scratches the small-sized natural graphite particles, thereby creating multi-directional channels on the surface of the natural graphite powder, improving the charging and discharging speed and efficiency. Detailed Implementation

[0035] The present application will be further described in detail below with reference to the embodiments.

[0036] Example of silicon dioxide preparation

[0037] Preparation Example 1: Silica was prepared by the following method:

[0038] Weigh out polyurethane resin and heat it to 180°C until it is completely melted to obtain polyurethane liquid.

[0039] 0.2 kg of polyurethane liquid was uniformly sprayed onto the surface of 1 kg of silica microspheres, followed by uniform spraying of 0.8 kg of silica whiskers. After mixing evenly, the mixture was dried and dispersed to obtain the finished silica product, which passed through a 150-mesh sieve. The silica microspheres had a particle size of 60 μm, and the silica whiskers had a length of 10 μm and a diameter of 100 nm.

[0040] Preparation Example 2: The difference between this preparation example and Preparation Example 1 is that:

[0041] 0.1 kg of polyurethane liquid was uniformly sprayed onto the surface of 1 kg of silica microspheres, followed by uniform spraying of 0.5 kg of silica whiskers. After mixing evenly and drying and dispersing, the finished silica product was obtained.

[0042] Preparation Example 3: The difference between this preparation example and Preparation Example 1 is that:

[0043] 0.4 kg of polyurethane liquid was uniformly sprayed onto the surface of 1 kg of silica microspheres, followed by uniform spraying of 1 kg of silica whiskers. After mixing evenly, the mixture was dried and dispersed to obtain the finished silica product.

[0044] Example of hydrogen peroxide solution preparation

[0045] Preparation Example 4: Hydrogen peroxide solution was prepared by the following method:

[0046] Weigh 1 kg of hydrogen peroxide and 0.2 kg of silicon dioxide prepared in Example 1, mix and stir evenly to obtain a hydrogen peroxide solution; the hydrogen peroxide concentration is 10%.

[0047] Preparation Example 5: Hydrogen peroxide solution was prepared by the following method:

[0048] Weigh 1 kg of hydrogen peroxide and 0.1 kg of silicon dioxide prepared in Example 2, mix and stir evenly to obtain a hydrogen peroxide solution; the hydrogen peroxide concentration is 10%.

[0049] Preparation Example 6: Hydrogen peroxide solution was prepared by the following method:

[0050] Weigh 1 kg of hydrogen peroxide and 0.3 kg of silicon dioxide prepared in Example 3, mix and stir evenly to obtain a hydrogen peroxide solution; the hydrogen peroxide concentration is 10%.

[0051] Example of abrasive preparation

[0052] Preparation Example 7: The abrasive was prepared using the following method:

[0053] Polyurethane is weighed and heated to 180°C until it is completely melted to obtain polyurethane liquid;

[0054] 32g of polyurethane liquid was uniformly sprayed onto the surface of 100g of silicon carbide whiskers, and then 150g of tetra-needle zinc oxide whiskers were uniformly sprayed on. After mixing evenly and drying and dispersing, the finished abrasive was obtained. The particle size of the finished abrasive was 15μm, and the needle length of the tetra-needle zinc oxide whiskers was 3μm.

[0055] Preparation Example 8: The difference between this preparation example and Preparation Example 7 is that:

[0056] 20g of polyurethane liquid was uniformly sprayed onto the surface of 100g of silicon carbide whiskers, followed by uniform spraying of 100g of tetra-needle zinc oxide whiskers. The mixture was then dried and dispersed to obtain the finished abrasive. The particle size of the abrasive was 10μm.

[0057] Preparation Example 9: The difference between this preparation example and Preparation Example 7 is that:

[0058] 50g of polyurethane liquid was uniformly sprayed onto the surface of 100g of silicon carbide whiskers, followed by uniform spraying of 200g of tetra-needle zinc oxide whiskers. The mixture was then dried and dispersed to obtain the finished abrasive. The particle size of the abrasive was 20μm.

[0059] Example

[0060] Example 1: A processing technology for a fast-charging and discharging lithium battery negative electrode material:

[0061] S1. Weigh natural graphite and place it in a crusher for the first crushing treatment, then pass it through a 10-mesh sieve. The material remaining on the sieve is then crushed a second time until all of it passes through a 10-mesh sieve to obtain natural graphite flakes. The natural graphite flakes are then subjected to a first ultrafine crushing in an airflow vortex crusher, resulting in a particle size of 40 μm. They are then dispersed in the hydrogen peroxide solution prepared in Preparation Example 4 and stirred at 500 r / min for 20 min. The particles are then filtered out and washed three times with water to remove the hydrogen peroxide. After ozone oxidation treatment for 20 min, they are subjected to ultrafine crushing again until the particle size is 3-5 μm to obtain natural graphite particles. The natural graphite particles are mixed with the abrasive prepared in Preparation Example 7 and surface treated. The mixture is stirred at 1000 r / min for 15 min, with a weight ratio of natural graphite particles to abrasive of 1:1.5, to obtain natural graphite powder.

[0062] S2. The asphalt is placed in an air jet crusher for ultra-fine crushing to a particle size of 3-5μm to obtain asphalt powder. Natural graphite powder is weighed and mixed with the asphalt powder evenly, with the weight of the asphalt powder accounting for 12% of the weight of the natural graphite powder. The mixture is extruded and granulated under a temperature of 240℃ and a pressure of 2MPa. After shaping, graphite particles are obtained. The graphite particles are graphitized at 2500℃. After deagglomeration, sieving, and demagnetization, the finished negative electrode material is obtained. The D50 of the negative electrode material is 14.8μm.

[0063] Example 2: The difference between this example and Example 1 is that:

[0064] S1. Weigh natural graphite and place it in a crusher for the first crushing treatment, then pass it through an 8-mesh sieve. The material remaining on the sieve is then crushed a second time until all of it passes through an 8-mesh sieve to obtain natural graphite flakes. The natural graphite flakes are then subjected to a first ultrafine crushing in an airflow vortex crusher, resulting in a particle size of 50 μm. They are then dispersed in the hydrogen peroxide solution prepared in Preparation Example 5 and stirred at 500 r / min for 20 min. The particles are then filtered out and washed three times with water to remove the hydrogen peroxide. After ozone oxidation treatment for 20 min, they are finally subjected to ultrafine crushing again until the particle size is 3-5 μm to obtain natural graphite particles. The natural graphite particles are mixed with the abrasive prepared in Preparation Example 8 and surface treated. The mixture is stirred at 1000 r / min for 15 min, with a weight ratio of natural graphite particles to abrasive of 1:1, to obtain natural graphite powder.

[0065] S2. The asphalt is placed in an air jet crusher for ultra-fine crushing until the particle size is 3-5μm to obtain asphalt powder. Natural graphite powder is weighed and mixed with the asphalt powder evenly, with the weight of the asphalt powder accounting for 10% of the weight of the natural graphite powder. The mixture is extruded and granulated under the conditions of 240℃ and 2MPa. After shaping, graphite particles are obtained. The graphite particles are graphitized at 2400℃. After deagglomeration, sieving, and demagnetization, the finished negative electrode material is obtained.

[0066] Example 3: The difference between this example and Example 1 is that:

[0067] S1. Weigh natural graphite and place it in a crusher for the first crushing treatment, then pass it through a 15-mesh sieve. The material remaining on the sieve is then crushed a second time until all of it passes through a 15-mesh sieve to obtain natural graphite flakes. The natural graphite flakes are then subjected to a first ultrafine crushing in an airflow vortex crusher, resulting in a particle size of 20 μm. They are then dispersed in the hydrogen peroxide solution prepared in Preparation Example 6 and stirred at 500 r / min for 20 min. The particles are then filtered out and washed three times with water to remove the hydrogen peroxide. After ozone oxidation treatment for 20 min, they are subjected to ultrafine crushing again until the particle size is 3-5 μm to obtain natural graphite particles. The natural graphite particles are mixed with the abrasive prepared in Preparation Example 9 and surface treated. The mixture is stirred at 1000 r / min for 15 min, with a weight ratio of natural graphite particles to abrasive of 1:2, to obtain natural graphite powder.

[0068] S2. The asphalt is placed in an air jet crusher for ultra-fine crushing until the particle size is 3-5μm to obtain asphalt powder. Natural graphite powder is weighed and mixed with asphalt powder evenly, with the weight of asphalt powder accounting for 15% of the weight of natural graphite powder. The mixture is extruded and granulated under the conditions of 240℃ and 2MPa, and after shaping, graphite particles are obtained. The graphite particles are graphitized at 2550℃, and then deagglomerated, sieved, and demagnetized to obtain the finished negative electrode material.

[0069] Example 4: The difference between this example and Example 1 is that:

[0070] S1. Weigh natural graphite and place it in a crusher for crushing. Then pass it through a 4-mesh sieve to obtain natural graphite flakes. 30%-40% of the flakes pass through a 10-mesh sieve, while the rest cannot pass through the 10-mesh sieve.

[0071] Example 5: The difference between this example and Example 1 is that:

[0072] Natural graphite flakes in S1 are subjected to ultra-fine crushing using an airflow vortex crusher to a particle size of 3-5μm, thus producing natural graphite particles.

[0073] Example 6: The difference between this example and Example 1 is that:

[0074] In S1, the natural graphite flakes were subjected to the first ultrafine crushing using an airflow vortex crusher, resulting in a particle size of 40 μm. They were then dispersed in the hydrogen peroxide solution prepared in Preparation Example 4 and stirred at 500 r / min for 20 min. The particles were then filtered out, washed three times with water to remove the hydrogen peroxide, and subjected to ultrafine crushing again until the particle size was 3-5 μm, thus obtaining natural graphite particles.

[0075] Example 7: The difference between this example and Example 1 is that:

[0076] Natural graphite flakes in S1 undergo a first ultrafine crushing process using an airflow vortex crusher, resulting in a particle size of 40 μm. After ozone oxidation treatment for 20 minutes, they are then subjected to another ultrafine crushing process to reduce the particle size to 3-5 μm, thus producing natural graphite particles.

[0077] Example 8: The difference between this example and Example 1 is that:

[0078] No silica was added to the S1 hydrogen peroxide solution.

[0079] Example 9: The difference between this example and Example 1 is that:

[0080] The silica in the S1 hydrogen peroxide solution is silica microspheres, meaning that the silica microspheres have not been treated with polyurethane liquid and silica whiskers.

[0081] Example 10: The difference between this example and Example 1 is that:

[0082] The abrasive in S1 is silicon carbide whiskers, meaning that the surface of the silicon carbide whiskers has not been treated with polyurethane liquid and four-needle zinc oxide whiskers.

[0083] Comparative Example

[0084] Comparative Example 1: The difference between this comparative example and Example 1 is that:

[0085] S1. Natural graphite is crushed to obtain natural graphite powder with a particle size of 8-10μm.

[0086] Comparative Example 2: This comparative example differs from Example 1 in that:

[0087] S1. Weigh natural graphite and place it in a crusher for the first crushing treatment, then pass it through a 10-mesh sieve. The material remaining on the sieve is then crushed a second time until all of it passes through a 10-mesh sieve to obtain natural graphite flakes. The natural graphite flakes are then subjected to a first ultrafine crushing in an airflow vortex crusher, resulting in a particle size of 40 μm. They are then dispersed in the hydrogen peroxide solution prepared in Preparation Example 4 and stirred at 500 r / min for 20 min. The particles are then filtered out and washed three times with water to remove the hydrogen peroxide. After ozone oxidation treatment for 20 min, they are finally subjected to ultrafine crushing again until the particle size is 3-5 μm to obtain natural graphite powder.

[0088] Performance testing

[0089] 1. Performance Testing

[0090] Anode materials were prepared using the methods described in Examples 1-10 and Comparative Examples 1-2, respectively. The anode material, an N-methylpyrrolidone solution containing 6-7% polyvinylidene fluoride (PVDF), and 2% conductive carbon black were mixed uniformly and coated onto copper foil. The coated electrode was then vacuum-dried in a vacuum drying oven at 110°C for 4 hours. Simulated battery assembly was conducted in an argon-filled Braun glove box (Germany). The electrolyte was 1M LiPF6 + EC:DEC = 1:1 (volume ratio), and a lithium metal sheet was used as the counter electrode. Electrochemical performance tests were performed using an Arbin BT2000 battery tester (USA), with a charge / discharge voltage range of 0.005 to 1.0V and a charge / discharge rate of 0.1C.

[0091] The compaction density of Examples 1-3, the first charge specific capacity and first discharge specific capacity of Examples 1-10 and Comparative Examples 1-2, and the charge and discharge efficiency of Examples 1-10 and Comparative Examples 1-2 were tested and the data were recorded.

[0092] Table 1 Performance Test Table

[0093]

[0094] As can be seen from Examples 1-3 and Table 1, the finished negative electrode material prepared in this application has a high compaction density, a high charge-discharge capacity, and a high charge-discharge efficiency.

[0095] Combining Examples 1 and 4-10 with Table 1, it can be seen that the natural graphite in Example 4, without ultrafine crushing and surface treatment, contains particles with large differences in particle size. Compared with Example 1, the charge / discharge capacity and charge / discharge efficiency of the negative electrode material prepared in Example 4 are smaller than those in Example 1. This indicates that small and large particle sizes coexist, and the particle size of the ultrafine crushing products is easily uneven, which affects the particle size of the negative electrode material. The smaller the particle size of the negative electrode material, the smaller the van der Waals forces that need to be overcome when lithium ions are inserted, enabling rapid and sufficient insertion, resulting in a higher charge / discharge capacity and charge / discharge efficiency of the finished negative electrode material.

[0096] In Example 5, the natural graphite particles were prepared without treatment with hydrogen peroxide solution and ozone. In Example 6, the natural graphite particles were prepared without treatment with ozone. In Example 7, the natural graphite particles were prepared without treatment with hydrogen peroxide solution. In Example 8, no silicon dioxide was added to the hydrogen peroxide solution. Compared with Example 1, the charge / discharge capacity and charge / discharge efficiency of the negative electrode materials prepared in Examples 5, 6, 7, and 8 are smaller than those in Example 1. This indicates that the oxidation treatment with hydrogen peroxide solution and ozone can increase the interlayer spacing, facilitate contact with asphalt, promote the graphite to become spherical, and increase the density of the negative electrode material. Furthermore, the silicon dioxide in the hydrogen peroxide solution can create slits on the graphite surface, which not only improves the crushing efficiency of ultrafine fragmentation but also improves the multidirectionality of electron channels, thereby increasing the charge / discharge speed and charge / discharge efficiency of the finished negative electrode material.

[0097] In Example 9, the silica in the hydrogen peroxide solution was silica microspheres. Compared to Example 1, the charge / discharge capacity and charge / discharge efficiency of the negative electrode material prepared in Example 9 were smaller than those in Example 1. This indicates that the combination of silica microspheres, polyurethane liquid, and silica whiskers, utilizing the larger specific surface area of ​​the silica microspheres and the needle-like whisker structure of silica, facilitates scratching the surface of natural graphite sheets, thereby generating more micro-gaps. This not only facilitates the crushing of natural graphite sheets to a particle size of 3-5 μm, but the presence of micro-gaps also improves the charge / discharge efficiency.

[0098] In Example 10, the abrasive was silicon carbide whiskers. Compared to Example 1, the charge / discharge capacity and charge / discharge efficiency of the negative electrode material prepared in Example 10 were smaller than those in Example 1. This indicates that the combination of silicon carbide whiskers, polyurethane liquid, and tetrapter-shaped zinc oxide whiskers, utilizing the spiky structure of the silicon carbide whiskers and the four-sided spiky structure of the tetrapter-shaped zinc oxide whiskers, further slits the small-sized natural graphite particles, thereby creating multi-directional channels on the surface of the natural graphite powder, improving the charge / discharge speed and efficiency.

[0099] Combining Example 1 and Comparative Examples 1-2 with Table 1, it can be seen that in Comparative Example 1, natural graphite was crushed to obtain natural graphite powder with a particle size of 8-10 μm. Compared with Example 1, the charge / discharge capacity and charge / discharge efficiency of the negative electrode material prepared in Comparative Example 1 are smaller than those in Example 1. This indicates that the natural graphite flakes after ultrafine crushing not only have more micro-scratches and microchannels on the surface, but also the smaller particle size of the powder formed into the negative electrode material facilitates lithium ion insertion, thereby improving the charge / discharge efficiency and charge / discharge capacity of the finished negative electrode material.

[0100] In Comparative Example 2, no surface treatment was performed during the preparation of natural graphite powder. Compared with Example 1, the charge-discharge capacity and charge-discharge efficiency of the negative electrode material prepared in Comparative Example 2 were smaller than those in Example 1. This indicates that the combination of natural graphite particles and abrasives, and the use of abrasives to create slits on the surface of natural graphite particles, generates more microchannels on the surface of natural graphite particles. By utilizing multidirectional electron channels, the charge-discharge efficiency and charge-discharge capacity of the finished negative electrode material are improved.

[0101] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A processing technology of fast charge-discharge lithium battery negative electrode material, characterized in that, It comprises the following steps: S1, taking natural graphite after crushing treatment to prepare natural graphite sheet; the natural graphite sheet is once ultra-micro broken to have a particle size of 20-50 μm, then is dispersed and stirred in hydrogen peroxide solution, the hydrogen peroxide solution is composed of hydrogen peroxide and silicon dioxide with a weight ratio of 1:0.1-0.3; after filtering out the particles, water washing, the silicon dioxide is composed of silicon dioxide microspheres, polyurethane liquid and silicon dioxide whiskers with a weight ratio of 1:0.1-0.4:0.5-1; then is treated by ozone oxidation, and finally is ultra-micro broken again to have a particle size of 2-5 μm to prepare natural graphite particles; the natural graphite particles are mixed and stirred with abrasive to prepare natural graphite powder, the weight ratio of natural graphite particles to abrasive is 1:1-2; the abrasive is prepared by sequentially loading polyurethane liquid and four acicular zinc oxide whiskers on silicon carbide whiskers with a weight ratio of 1:0.2-0.5:1-2; S2, the natural graphite powder is mixed and stirred with asphalt powder, the weight of asphalt powder accounts for 10-15% of the weight of natural graphite powder, after granulation, shaping, graphitization, depolymerization, screening and magnetic removal, the finished negative electrode material is prepared.

2. The processing technology of a fast charge-discharge lithium battery negative material according to claim 1, characterized in that: The crushing treatment in S1 is layered crushing, after the first crushing, the sieve residue is twice crushed until all the sieve residue is passed through an 8-15 mesh sieve.

3. The process for processing negative material of fast charge-discharge lithium battery according to claim 1, characterized in that, The abrasive has a particle size of 10-20 μm.

4. The process for processing negative material of fast charge-discharge lithium battery according to claim 1, characterized in that, The asphalt powder is ultra-micro broken to have a particle size of 3-5 μm.

5. The process for processing of fast charge-discharge lithium battery anode material as claimed in claim 1 wherein, The graphitization temperature is 2400-2550 ℃.

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