Negative electrode material, battery

Abstract

This application provides a negative electrode material and a battery. The negative electrode material includes graphite, and the surface and / or interior of the graphite have pores. The pore volume of the negative electrode material is V cm³. 3 / kg, true density is D g / cm³ 3 Specific surface area is S m 2 / g, graphitization degree is G%, where 0.7≤V S / D≤3.95, while 89≤G≤93. The negative electrode material and battery provided in this application can improve the rate performance and cycle performance of graphite negative electrode materials at high rate currents.

Description

Anode materials, batteries

[0001] This application is a divisional application of Chinese patent application No. 202380009570.4, filed on June 28, 2023, entitled "Negative Electrode Material, Battery". Technical Field

[0002] This application relates to the field of negative electrode material technology, specifically to negative electrode materials and batteries. Background Technology

[0003] Lithium-ion batteries, due to their excellent performance, have shown promising application prospects in portable consumer electronics, power tools, new energy vehicles, and energy storage. Since the commercialization of lithium-ion batteries, graphite-based anode materials have been the most mature. The current main development direction for lithium-ion batteries is high capacity, high rate capability, and high safety; therefore, the development of high-performance graphite anodes is crucial for achieving high-rate performance and good cycle performance in lithium-ion batteries.

[0004] From a technical perspective, the unique layered structure of graphite determines the properties of Li. ＋ Lithium ions can only be embedded from the end face of the material and gradually diffuse into the interior of the particles, resulting in a low diffusion rate and poor rate performance. At the same time, lithium embedding at high rates can easily cause lithium ion enrichment on the surface of the graphite anode. When the lithium ion concentration at the interface reaches saturation, lithium ions will be deposited in the form of metal, which will prevent the diffusion channels and electrochemical reaction area from being fully utilized.

[0005] Therefore, at the current stage where graphite materials have been developed to a high degree of maturity, simply improving one parameter is no longer sufficient to meet the market demand for graphite anode materials with high rate performance and good cycle performance. It is necessary to explore the mechanism of action of multiple factors working together to develop graphite anode materials that meet market demands. Summary of the Invention

[0006] In view of this, this application addresses the shortcomings of the prior art by providing a new negative electrode material and battery. This negative electrode material achieves precise control over the internal and / or surface pore volume, specific surface area, and true density, keeping them within a reasonable range, thereby improving the capacity and rate performance of the negative electrode material.

[0007] In a first aspect, this application provides a negative electrode material comprising graphite, wherein the surface and / or interior of the graphite have pores, and the pore volume of the negative electrode material is V cm³. 3 / kg, true density is D g / cm³ 3 Specific surface area is S m 2 / g, graphitization degree is G%, where 0.7≤V S / D≤3.95, and 89≤G≤93; the pore volume was tested using an ASAP2460 instrument from Micron Technology, USA, and calculated using the BJH Desorption Cumulative Volume of Pores model in the pore size range of 17 Å to 3000 Å.

[0008] In some embodiments, the pore volume of the negative electrode material is V cm. 3 / kg, 1.812≤V≤4.987.

[0009] In some embodiments, the specific surface area of ​​the negative electrode material is S m 2 / g, 0.872≤S≤1.773.

[0010] In some embodiments, the true density of the negative electrode material is D g / cm³. 3 , 2.238≤D≤2.257.

[0011] In some embodiments, the pores include at least one of micropores and mesopores.

[0012] In some embodiments, the pores extend from the surface of the graphite inwards.

[0013] In some embodiments, the graphite is synthetic graphite.

[0014] In some embodiments, the average aperture of the pore is 50 Å to 200 Å.

[0015] In some embodiments, the interlayer spacing of the (002) plane of the negative electrode material is determined by X-ray diffraction to be d. 002 3.356Å≤d 002 ≤3.364Å.

[0016] In some embodiments, the particle size D of the negative electrode material 50 The size ranges from 10μm to 20μm.

[0017] In some embodiments, the negative electrode material further includes amorphous carbon, which is present on the graphite surface and / or dispersed between graphite particles.

[0018] In some embodiments, the negative electrode material further includes an amorphous carbon coating layer located on the surface of the graphite, the thickness of which is 10 nm to 500 nm.

[0019] In some embodiments, the amorphous carbon accounts for 0.1 wt% to 3 wt% of the mass of the negative electrode material.

[0020] In a second aspect, this application provides a battery comprising the negative electrode material according to the first aspect.

[0021] The technical solution of this application has at least the following beneficial effects: The negative electrode material provided in this application includes graphite, and the surface and / or interior of the graphite have pores that extend from the surface of the graphite inward. While retaining the regular layered structure of the graphite in the negative electrode material, it generates abundant pores on and near the surface of the graphite. The pore volume of the negative electrode material is V cm³. 3 / kg, true density is D g / cm³ 3 Specific surface area is S m 2 / g, graphitization degree is G%, where 0.7≤V S / D ≤ 3.95, while 89 ≤ G ≤ 93. A certain range of pore volume is favorable for Li... ＋By embedding lithium ions into the interior along the pore structure of the material surface, the diffusion rate of lithium ions is increased. A certain specific surface area can ensure a sufficient electrochemical reaction interface, promoting the diffusion of lithium ions at the solid-liquid interface and within the solid phase, reducing concentration polarization, and thus improving the capacity and rate performance of the anode material. However, simply meeting the requirements of suitable pore volume and specific surface area is not enough to improve the rate performance of the anode material. This is because, after lithium ions diffuse to the graphite surface, if the carbon atoms in the graphite are arranged in a disordered manner and lack sufficient order, the resistance to lithium ions entering the interior of the graphite material and combining with carbon atoms to undergo electrochemical reactions is relatively large. At the same time, since graphite is polycrystalline, especially artificial graphite, there are grain boundary defects between grains. The stress at these grain boundary defects is uneven. Grain boundaries are a type of crystal plane defect and are prone to cracking. Under external force, they are more likely to split along the grain boundary direction, resulting in intergranular fracture. Ultimately, the splitting of the crystal plane parallel to the graphite crystal plane direction forms the outer surface of the graphite particles. Because these outer surfaces are perpendicular to the direction of lithium-ion diffusion, they must cross the carbon plane, making it difficult for lithium ions to enter the graphite interior. Simultaneously, lithium ions may aggregate on the carbon surface to form lithium clusters, thus inhibiting lithium diffusion or forming lithium deposits. Ultimately, the diffusion channels and electrochemical reaction area cannot be fully utilized. Therefore, this application provides a good diffusion path for lithium-ion diffusion by controlling the degree of graphitization and true density, while simultaneously designing the pore structure and pore distribution to concentrate the stress inside the graphite around the pores and disperse the stress at the grain boundaries. This allows the graphite to first crack and fracture at the pores when subjected to external force, which is beneficial for the formation of... Transgranular fracture, after exposing the channels, ultimately forms the outer surface of graphite particles. Transgranular fracture helps increase the number of channel entrances on the graphite particle surface parallel to the lithium-ion diffusion direction. Furthermore, the inner surface of the channels itself has a certain number of channel entrances for lithium-ion diffusion into the graphite interlayers. Simultaneously, the presence of numerous defects allows for edge-end lithium storage. Therefore, fracture at the channels to form the outer surface of the particles can construct more graphite microcrystalline surfaces parallel to the lithium-ion diffusion path. This not only creates more lithium-ion diffusion paths within the graphite particles but also further creates more channel entrances for lithium-ion entry on the particle surface. Simultaneously, considering that a higher degree of graphitization is beneficial to the diffusion environment and reduces obstacles to lithium-ion transport caused by defects such as partial crystal distortion, a high degree of graphitization influences the number of polycrystalline grain boundaries and lattice distortion in graphite, resulting in a high degree of order and compactness in the interlayer arrangement, which is beneficial to improving the true density and ensuring that the anode material exhibits a high specific capacity. This application will apply the V... S / D control within the above range simultaneously controls the degree of graphitization of the material, which is beneficial for lithium ions and sufficient carbon atoms to combine under low resistance. This gives the anode material sufficient space for lithium insertion / extraction reaction, which is conducive to obtaining anode materials with better rate performance and capacity. Attached Figure Description

[0022] Figure 1 is a scanning electron microscope (SEM) image of the graphite anode material provided in Embodiment 2 of this application; Figure 2 is another SEM image of the graphite anode material provided in Embodiment 2 of this application; Figure 3 is a SEM image of the graphite anode material provided in Embodiment 11 of this application; Figure 4 is another SEM image of the graphite anode material provided in Embodiment 11 of this application. Detailed Implementation

[0023] To better illustrate this application and facilitate understanding of its technical solutions, the following detailed description is provided. However, the following embodiments are merely simplified examples and do not represent or limit the scope of protection of this application. The scope of protection of this application is determined by the claims.

[0024] Since the commercialization of lithium-ion batteries, graphite-based anode materials have been the most mature. The unique layered structure of graphite determines the... ＋ Lithium ions can only be embedded from the end face of the material and gradually diffuse into the interior of the particles, resulting in a low diffusion rate and poor rate performance. At the same time, lithium embedding at high rates can easily cause lithium ion enrichment on the surface of the graphite anode. When the lithium ion concentration at the interface reaches saturation, lithium ions will be deposited in the form of metal, which will prevent the diffusion channels and electrochemical reaction area from being fully utilized.

[0025] Therefore, this application provides a negative electrode material comprising graphite, wherein the graphite has pores on its surface and / or interior, the pores extending from the surface of the graphite inwards, and the pore volume of the negative electrode material is V cm³. 3 / kg, true density is D g / cm³ 3 Specific surface area is S m 2 / g, graphitization degree is G%, where 0.7≤V S / D≤3.95, and 89≤G≤93; the pore volume was tested using an ASAP2460 instrument from Micron Technology, USA, and calculated using the BJH Desorption Cumulative Volume of Pores model in the pore size range of 17 Å to 3000 Å.

[0026] The negative electrode material provided in this application includes graphite, wherein the graphite has pores on its surface and / or interior, the pores extending from the surface of the graphite inward, thereby maintaining the regular layered structure of the graphite in the negative electrode material while creating abundant pores on and near the surface of the graphite. The pore volume of the negative electrode material is V cm³. 3 / kg, true density is D g / cm³ 3 Specific surface area is S m 2 / g, graphitization degree is G%, where 0.7≤V S / D ≤ 3.95, while 89 ≤ G ≤ 93. A certain range of pore volume is favorable for Li... ＋ By embedding lithium ions into the interior along the pore structure of the material surface, the diffusion rate of lithium ions is increased. A certain specific surface area can ensure a sufficient electrochemical reaction interface, promoting the diffusion of lithium ions at the solid-liquid interface and within the solid phase, reducing concentration polarization, and thus improving the capacity and rate performance of the anode material. However, simply meeting the requirements of suitable pore volume and specific surface area is not enough to improve the rate performance of the anode material. This is because, after lithium ions diffuse to the graphite surface, if the carbon atoms in the graphite are arranged in a disordered manner and lack sufficient order, the resistance to lithium ions entering the interior of the graphite material and combining with carbon atoms to undergo an electrochemical reaction is relatively large. At the same time, because graphite is polycrystalline, especially artificial graphite, there are grain boundary defects between grains. The stress at these grain boundary defects is uneven, making them prone to cracking. Under external force, they are easily split. Ultimately, the splitting of the crystal planes parallel to the graphite crystal planes forms the outer surface of the graphite particles. Because these outer surfaces are perpendicular to the direction of lithium-ion diffusion, they must cross the carbon plane, making it difficult to penetrate the graphite interior. Simultaneously, lithium clusters may accumulate on the carbon surface, inhibiting lithium diffusion or forming lithium deposits. Ultimately, the diffusion channels and electrochemical reaction area cannot be fully utilized. Therefore, this application, by controlling the degree of graphitization and true density to provide a good diffusion path for lithium-ion diffusion, combines the design of pore structure and void distribution to concentrate more internal stress around the pores, reducing stress at grain boundaries. This causes the graphite to crack and fracture first at the pores when subjected to external force, ultimately constructing the graphite particle surface. This allows for the creation of more graphite microcrystal surfaces parallel to the lithium-ion diffusion path, creating more lithium-ion diffusion paths not only inside the graphite particles but also creating more entry points for lithium-ion entry on the particle surface. Furthermore, a higher degree of graphitization is beneficial to the diffusion environment, reducing obstacles to lithium-ion transport caused by crystal defects, ensuring the anode material exhibits a high specific capacity. This application will further enhance the V of the anode material. S / D control within the above range simultaneously controls the degree of graphitization of the material, which is beneficial for lithium ions and sufficient carbon atoms to combine under low resistance. This gives the anode material sufficient space for lithium insertion / extraction reaction, which is conducive to obtaining anode materials with better rate performance and capacity.

[0027] In some embodiments, the pore volume V cm of the negative electrode material 3 / kg, 1.812≤V≤4.987, specifically it can be 1.812, 2.016, 2.582, 2.897, 3.348, 3.476, 3.755, 3.896, 4.013, 4.167, 4.275, 4.512 or 4.987, etc., without limitation. When electrochemical reactions occur inside the electrode, the pores create more lithium-ion diffusion channels and electrochemical reaction interfaces for the negative electrode material, which can promote the diffusion of lithium ions at the solid-liquid interface and in the solid phase, reduce concentration polarization, and help improve the rate performance of the negative electrode material.

[0028] In some embodiments, the specific surface area of ​​the negative electrode material is S m 2 / g, 0.872≤S≤1.773; specifically, it can be 1.773, 1.643, 1.593, 1.532, 1.498, 1.446, 1.386, 1.315, 1.267, 1.157, 1.044, 0.912, or 0.872, etc., without limitation here. Understandably, an excessively large specific surface area can easily lead to the formation of an excessive solid electrolyte film, consuming too much irreversible lithium salt and reducing the initial efficiency of the battery.

[0029] In some embodiments, the true density of the negative electrode material is D g / cm³. 3 2.210≤D≤2.265; specifically, it can be 2.2385, 2.2481, 2.2440, 2.2372, 2.2476, 2.2502, 2.2514 or 2.262, etc., which are not limited here.

[0030] In some embodiments, the degree of graphitization of the negative electrode material is G%, 89≤G≤93; specifically, it can be 89, 90, 90.5, 91, 91.5, 92, 92.5 or 93, etc., which are not limited here.

[0031] In some embodiments, the pores include at least one of micropores and mesopores.

[0032] In some embodiments, the average pore size is 50 Å to 200 Å, specifically 50 Å, 60 Å, 70 Å, 80 Å, 90 Å, 100 Å, 120 Å, 140 Å, 160 Å, or 200 Å, etc., and is not limited thereto. Controlling the average pore size within the above range is beneficial to Li ＋ Lithium is transported from the material surface along the pore structure into the interior of the graphite, where it undergoes further lithium insertion / extraction reactions. Preferably, the average pore size is 80 Å to 140 Å.

[0033] In some embodiments, the pores extend from the surface of the graphite inwards.

[0034] In some embodiments, the graphite is synthetic graphite.

[0035] In some embodiments, the particle size D of the negative electrode material 50 The particle size distribution ranges from 10 μm to 20 μm. Specifically, it can be 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 18 μm, 19 μm, or 20 μm, etc., and is not limited here. It should be noted that the cumulative particle size distribution based on volume is determined using laser diffraction, D. 50 This indicates the particle size corresponding to a cumulative particle size distribution percentage of 50%.

[0036] In some embodiments, the interlayer spacing of the (002) plane of the negative electrode material is determined by X-ray diffraction to be d. 002 3.356Å≤d 002 ≤3.364Å. Interlayer spacing d 002 Within the above range, it can be seen that the graphite particles have a high degree of graphite crystallinity, that is, a high degree of graphitization, and the product has a high capacity.

[0037] In some embodiments, the negative electrode material further includes an amorphous carbon coating layer located on the surface of the graphite, the thickness of which is 10nm to 500nm; specifically, it can be 10nm, 15nm, 20nm, 30nm, 50nm, 80nm, 100nm, 150nm, 180nm, 200nm, 400nm, or 500nm; preferably, the thickness of which is 10nm to 100nm.

[0038] In some embodiments, the negative electrode material further includes amorphous carbon, which is present on the graphite surface and / or dispersed between graphite particles. Specifically, the graphite particles may be embedded within the amorphous carbon material, with some graphite particles exposed on the surface of the amorphous carbon material.

[0039] In some embodiments, the anode material also includes amorphous carbon, which accounts for 0.1wt% to 3wt% of the mass of the amorphous carbon in the anode material. Specifically, the mass percentage of amorphous carbon in the anode material can be 0.1wt%, 0.3wt%, 0.5wt%, 1wt%, 2wt%, 2.5wt%, or 3wt%. The presence of amorphous carbon provides more irregular and open diffusion paths for lithium ions, which is beneficial to improving the rate performance of the material.

[0040] In some implementations, the negative electrode material retains ≥90% of its capacity after 500 cycles of 1C charging. Specifically, this can be 91.8%, 92.3%, 90.6%, 92.4%, 93.5%, etc., and is not limited here.

[0041] This application also provides a method for preparing a negative electrode material, comprising the following steps: S10, mixing softened asphalt with an alkaline solution of concentration 0.01 mol / L to 0.05 mol / L, and subjecting the mixture to ultrasonic treatment to obtain a mixture, wherein the mass ratio of saturated fraction to aromatic fraction in the asphalt is (5~20):(95~80); S20, drying and crushing the solid product after washing the mixture to obtain powder D. 50 The particle size is 10μm to 20μm; S30, the powder is carbonized at 500℃ to 1200℃ under an inert atmosphere to obtain a precursor; S40, the precursor is graphitized at 2800℃ to 3200℃ to obtain a negative electrode material.

[0042] The method for preparing the negative electrode material provided in this application involves mixing asphalt with a low-concentration alkaline solution, and then using ultrasonic etching to form a porous structure in situ within the asphalt. This increases the effective reaction area of ​​the material and enhances the lithium-ion insertion pathway. The etched powder is then carbonized. During carbonization, impurities, volatiles, and unstable substances within the material decompose and escape, further expanding the pore size and depth. The carbonized product is then graphitized to form graphite with abundant and regular pores, achieving precise control over the pore volume and regulating the internal stress distribution of the graphite to some extent. Ultimately, this increases the reactive area of ​​the negative electrode active material in the electrode, which is beneficial for improving the material's high-rate charge-discharge performance. This process is simple, has low production costs, and the resulting graphite negative electrode material exhibits high specific capacity, excellent high-rate charge-discharge performance, and superior cycle performance, meeting the needs of consumer and power users for high negative electrode energy density and fast-charging performance.

[0043] The technical solution of this application is described in detail below: S10, the softened asphalt is mixed with an alkaline solution with a concentration of 0.01 mol / L to 0.05 mol / L and subjected to ultrasonic treatment to obtain a mixture, wherein the mass content ratio of saturated fraction to aromatic fraction in the asphalt is (5~20):(95~80).

[0044] In some embodiments, the asphalt includes coal tar pitch and / or petroleum asphalt, and the petroleum asphalt may be modified asphalt and mesophase asphalt, etc.

[0045] In some embodiments, the mass ratio of saturated components to aromatic components in asphalt is (5~20):(95~80). Specifically, it can be 5:95, 8:92, 10:90, 13:87, 15:85, 18:82, 20:80, etc. Of course, it can also be other values ​​within the above range, which are not limited here. By controlling the mass ratio of saturated to aromatic components in asphalt, the higher the aromatic content, the better the fluidity of the asphalt, the lower the softening temperature, and the higher the volatile content. The volatile components decompose and escape during carbonization, which further enlarges the pore diameter and depth formed by etching. This concentrates more stress inside the graphite around the pores, reduces stress at the grain boundaries, and causes the graphite to crack and break first from the pores when subjected to external force, ultimately building the graphite particle surface. This allows for the creation of more graphite microcrystalline surfaces parallel to the lithium-ion diffusion path, not only creating more lithium-ion diffusion paths inside the graphite particles but also creating more channels for lithium-ion entry on the particle surface. This is beneficial for obtaining anode materials with better rate performance and lower residual carbon content.

[0046] In some embodiments, asphalt is heated to 50°C to 80°C to soften it, forming liquid asphalt. The softening temperature can be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, or 80°C, or other values ​​within the above range, which are not limited here.

[0047] In some embodiments, the alkaline solution includes at least one of NaOH solution and KOH solution.

[0048] In some embodiments, the concentration of the alkaline solution is 0.01 mol / L to 0.05 mol / L, specifically 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.045 mol / L, or 0.05 mol / L, etc., or other values ​​within the above range, which are not limited here. Excessive alkaline solution concentration will lead to too many pores formed by etching on the asphalt surface, resulting in an excessively large pore volume and specific surface area in the final graphite anode material, making it difficult to incorporate V... Maintaining the S / D ratio within the ideal range is detrimental to improving the high-rate charge-discharge performance and cycle performance of the negative electrode material. Increasing the V of the negative electrode material... By controlling the S / D ratio within the above range, the anode material has sufficient space for lithium insertion / extraction chemical reactions, which is beneficial for obtaining anode materials with better rate performance and capacity.

[0049] In some embodiments, the material ratio of asphalt to alkaline solution is 50g / 100ml to 100g / 100ml, specifically 50g / 100ml, 60g / 100ml, 70g / 100ml, 75g / 100ml, 80g / 100ml, 85g / 100ml, 90g / 100ml, or 100g / 100ml, etc., or other values ​​within the above range, which are not limited here. Controlling the material ratio of asphalt to alkaline solution can facilitate the alkaline solution to fully etch the softened asphalt, thereby etching an appropriate number of pores on the asphalt surface, reducing the stress at the grain boundaries of the graphite obtained after graphitization, which is conducive to creating more lithium-ion diffusion paths and improving the specific capacity and rate performance of the anode material.

[0050] In some embodiments, the ultrasonic treatment time under heat preservation is 5h to 10h, specifically 5h, 6h, 7h, 8h, 9h, or 10h, but not limited to the listed values; other unlisted values ​​within this range are also applicable. During ultrasonic treatment, the alkaline solution continuously impacts and erodes the asphalt, causing in-situ etching of the asphalt particles to form a porous structure. This porous structure creates more lithium-ion diffusion channels and electrochemical reaction interfaces for the negative electrode material, promoting lithium-ion diffusion at the solid-liquid interface and within the solid phase, reducing concentration polarization, and thus improving the rate performance of the negative electrode material.

[0051] S20, the solid product after washing the mixture is dried and crushed to obtain powder D. 50 The size is 10μm to 20μm.

[0052] In some embodiments, the mixture is cooled to room temperature, repeatedly washed and filtered with distilled water until the filtrate is neutral, and solid-liquid separation is performed to obtain a solid product.

[0053] In some embodiments, the solid-liquid separation method includes at least one of centrifugation and filtration, and the filtration can be at least one of atmospheric pressure filtration, vacuum filtration, and reduced pressure filtration.

[0054] In some embodiments, the drying temperature is 80°C to 120°C, specifically 80°C, 90°C, 100°C, 110°C and 120°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0055] In some embodiments, the median particle size D of the powder obtained from crushing 50The median particle size is 10μm to 20μm, more specifically, it can be 12μm, 13μm, 14μm, 16μm, 18μm, 18.5μm, 19μm, or 20μm, but it is not limited to the listed values; other unlisted values ​​within this range also apply. Multiple experiments have shown that controlling the median particle size of the powder within the above range is beneficial for balancing processing performance, capacity, and rate performance.

[0056] S30, the powder is carbonized at 500℃~1200℃ under an inert atmosphere to obtain the precursor.

[0057] In some embodiments, the heating rate of the carbonization process is specifically 2°C / min, 3°C / min, 5°C / min, 6°C / min, 8°C / min, 9°C / min, or 10°C / min, etc. Understandably, a heating rate within the above range facilitates the escape of volatiles from the raw material at different rates, further enlarging and / or deepening the pore size of the pore structure. This, combined with the heating rate of the subsequent graphitization process, achieves a result satisfying 0.70 ≤ V Anode material with S / D ≤ 3.95.

[0058] In some embodiments, the carbonization temperature may specifically be 500°C, 550°C, 600°C, 700°C, 750°C, 800°C, 850°C, 900°C, 1000°C, or 1200°C, but is not limited to the listed values; other unlisted values ​​within this range are also applicable. Understandably, a carbonization temperature within the above range is beneficial for the removal of volatile substances and other compounds from the powder.

[0059] In some embodiments, the heat treatment holding time for carbonization is 2h to 10h, specifically 2h, 3h, 4h, 4.5h, 5h, 6h, 8h or 10h, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0060] S40 involves graphitizing the precursor at 2800℃~3200℃ to obtain the negative electrode material.

[0061] In some embodiments, the holding temperature for graphitization treatment can be 2800℃, 2850℃, 2900℃, 2950℃, 3000℃, 3100℃ or 3200℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0062] In some implementations, the heat treatment time for graphitization is 2h to 10h, specifically 2h, 3h, 4h, 4.5h, 5h, 6h, 8h or 10h, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0063] In some embodiments, the heating rate for graphitization treatment can be from 2°C / min to 10°C / min, specifically 2°C / min, 3°C / min, 4°C / min, 6°C / min, 8°C / min, or 10°C / min, but is not limited to the listed values; other unlisted values ​​within this range are also applicable. A specific heating rate is beneficial for controlling the formation of pores and specific surface area within and / or on the graphite material.

[0064] In some embodiments, after graphitization, at least one of crushing, sieving, and demagnetization is performed. Preferably, after graphitization, crushing, demagnetization, and sieving are performed sequentially.

[0065] In some implementations, the pulverization method is any one of a mechanical pulverizer, an air jet mill, and a cryogenic pulverizer.

[0066] In some implementations, the screening method is any one of a fixed screen, drum screen, resonant screen, roller screen, vibrating screen, and chain screen, and the screening mesh is 100 to 500 mesh. Specifically, the screening mesh can be 100 mesh, 200 mesh, 250 mesh, 325 mesh, 400 mesh, 500 mesh, etc. Controlling the particle size of the negative electrode material within the above range is beneficial to improving the processing performance of the negative electrode material.

[0067] In some implementations, the demagnetizing equipment is any one of a permanent magnet drum magnetic separator, an electromagnetic iron remover, and a pulsed high-gradient magnetic separator. Demagnetization is to ultimately control the magnetic material content of the negative electrode material, reduce the discharge effect of magnetic materials on the lithium-ion battery, and improve the safety of the battery during use.

[0068] This application also provides a battery comprising the aforementioned negative electrode material.

[0069] Those skilled in the art will understand that the battery preparation methods described above are merely embodiments. Without departing from the disclosure of this application, other methods commonly used in the art can be employed to prepare other types of batteries for testing, such as sodium-ion batteries and potassium-ion batteries.

[0070] The embodiments of this application will be further described below with reference to several examples. However, the embodiments of this application are not limited to the specific embodiments described below. Appropriate modifications and implementations can be made within the scope of protection.

[0071] Example 1 The preparation method of the negative electrode material in this example includes the following steps: (1) After heating the asphalt to 80°C to soften it, it is mixed with 0.05 mol / L KOH alkaline solution and ultrasonically treated at 80°C for 10 h to obtain a mixture, wherein the asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 5:95; (2) The mixture is cooled to room temperature, repeatedly washed and filtered with distilled water until the filtrate is neutral, the solvent is removed by vacuum filtration, and then placed in an oven for vacuum drying for 10 h and crushed to obtain powder (D 50 (3) The powder was carbonized at 1200℃ for 10 h to obtain a precursor; (4) The precursor was graphitized at 3000℃ for 8 h to obtain a graphite anode material.

[0072] Example 2 The preparation method of the negative electrode material in this example includes the following steps: (1) After heating the asphalt to 80°C to soften it, it is mixed with 0.04 mol / L KOH alkaline solution and ultrasonically treated at 80°C for 10 h to obtain a mixture, wherein the asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 10:90; (2) The mixture is cooled to room temperature, repeatedly washed and filtered with distilled water until the filtrate is neutral, the solvent is removed by vacuum filtration, and then placed in an oven for vacuum drying for 10 h and crushed to obtain powder (D 50 (16.9μm); (3) Carbonize the powder at 1000℃ for 10h to obtain the precursor; (4) Graphitize the precursor at 3000℃ for 8h to obtain the graphite anode material.

[0073] Example 3 The preparation method of the negative electrode material in this example includes the following steps: (1) After heating the asphalt to 80°C to soften it, it is mixed with 0.03 mol / L KOH alkaline solution and ultrasonically treated at 80°C for 10 h to obtain a mixture, wherein the asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 15:85; (2) The mixture is cooled to room temperature, repeatedly washed and filtered with distilled water until the filtrate is neutral, the solvent is removed by vacuum filtration, and then placed in an oven for vacuum drying for 10 h and crushed to obtain powder (D 50 (16.2μm); (3) Carbonize the powder at 1200℃ for 10h to obtain the precursor; (4) Graphitize the precursor at 2900℃ for 8h to obtain the graphite anode material.

[0074] Example 4 The preparation method of the negative electrode material in this example includes the following steps: (1) After heating the asphalt to 80°C to soften it, it is mixed with 0.02 mol / L KOH alkaline solution and ultrasonically treated at 80°C for 10 h to obtain a mixture, wherein the asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 20:80; (2) The mixture is cooled to room temperature, repeatedly washed and filtered with distilled water until the filtrate is neutral, the solvent is removed by vacuum filtration, and then placed in an oven for vacuum drying for 10 h and crushed to obtain powder (D 50 (15.7μm); (3) Carbonize the powder at 1200℃ for 10h to obtain the precursor; (4) Graphitize the precursor at 2800℃ for 8h to obtain the graphite anode material.

[0075] Example 5 The preparation method of the negative electrode material in this example includes the following steps: (1) After heating the asphalt to 80°C to soften it, it is mixed with 0.01 mol / L KOH alkaline solution and ultrasonically treated at 80°C for 10 h to obtain a mixture, wherein the asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 20:80; (2) The mixture is cooled to room temperature, repeatedly washed and filtered with distilled water until the filtrate is neutral, the solvent is removed by vacuum filtration, and then placed in an oven for vacuum drying for 10 h and crushed to obtain powder (D 50 (15.4μm); (3) Carbonize the powder at 500℃ for 10h to obtain the precursor; (4) Graphitize the precursor at 2800℃ for 8h to obtain the graphite anode material.

[0076] Example 6 The preparation method of the negative electrode material in this example includes the following steps: (1) After heating the asphalt to 80°C to soften it, it is mixed with 0.05mol / L KOH alkaline solution and ultrasonically treated at 70°C for 8 hours to obtain a mixture, wherein the asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 20:80; (2) The mixture is cooled to room temperature, repeatedly washed and filtered with distilled water until the filtrate is neutral, the solvent is removed by vacuum filtration, and then placed in an oven for vacuum drying for 10 hours and crushed to obtain powder (D 50 (16.1μm); (3) Carbonize the powder at 1200℃ for 10h to obtain the precursor; (4) Graphitize the precursor at 3000℃ for 8h to obtain the graphite anode material.

[0077] Example 7 The preparation method of the negative electrode material in this example includes the following steps: (1) After heating the asphalt to 70°C to soften it, it is mixed with 0.04mol / L KOH alkaline solution and ultrasonically treated at 70°C for 8 hours to obtain a mixture, wherein the asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 20:80; (2) The mixture is cooled to room temperature, repeatedly washed and filtered with distilled water until the filtrate is neutral, the solvent is removed by vacuum filtration, and then placed in an oven for vacuum drying for 10 hours and crushed to obtain powder (D 50 (16.8μm); (3) Carbonize the powder at 1000℃ for 10h to obtain the precursor; (4) Graphitize the precursor at 3000℃ for 8h to obtain the graphite anode material.

[0078] Example 8 The preparation method of the negative electrode material in this example includes the following steps: (1) After heating the asphalt to 70°C to soften it, it is mixed with 0.03mol / L KOH alkaline solution and ultrasonically treated at 70°C for 8 h to obtain a mixture, wherein the asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 20:80; (2) The mixture is cooled to room temperature, repeatedly washed and filtered with distilled water until the filtrate is neutral, the solvent is removed by vacuum filtration, and then placed in an oven for vacuum drying for 10 h and crushed to obtain powder (D 50 (16.7μm); (3) Carbonize the powder at 1000℃ for 10h to obtain the precursor; (4) Graphitize the precursor at 2900℃ for 8h to obtain the graphite anode material.

[0079] Example 9 The preparation method of the negative electrode material in this example includes the following steps: (1) After heating the asphalt to 70°C to soften it, it is mixed with 0.02mol / L KOH alkaline solution and ultrasonically treated at 70°C for 8 hours to obtain a mixture, wherein the asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 20:80; (2) The mixture is cooled to room temperature, repeatedly washed and filtered with distilled water until the filtrate is neutral, the solvent is removed by vacuum filtration, and then placed in an oven for vacuum drying for 10 hours and crushed to obtain powder (D 50 (16.8μm); (3) Carbonize the powder at 800℃ for 10h to obtain the precursor; (4) Graphitize the precursor at 2800℃ for 8h to obtain the graphite anode material.

[0080] Example 10 The preparation method of the negative electrode material in this example includes the following steps: (1) After heating the asphalt to 70°C to soften it, it is mixed with 0.01mol / L KOH alkaline solution and ultrasonically treated at 70°C for 8 hours to obtain a mixture, wherein the asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 20:80; (2) The mixture is cooled to room temperature, repeatedly washed and filtered with distilled water until the filtrate is neutral, the solvent is removed by vacuum filtration, and then placed in an oven for vacuum drying for 10 hours and crushed to obtain powder (D 50 (15.6μm); (3) Carbonize the powder at 500℃ for 10h to obtain the precursor; (4) Graphitize the precursor at 2800℃ for 8h to obtain the graphite anode material.

[0081] The only difference between Example 11 and Example 1 is that in step (1), the asphalt is heated to 60°C to soften it, then mixed with 0.05 mol / L NaOH alkaline solution, and ultrasonically treated at 60°C for 6 h to obtain a mixture. The asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 20:80.

[0082] The only difference between Example 12 and Example 2 is that in step (1), the asphalt is heated to 60°C to soften it, then mixed with 0.04 mol / L NaOH alkaline solution, and ultrasonically treated at 60°C for 6 h to obtain a mixture. The asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 20:80.

[0083] The only difference between Example 13 and Example 3 is that in step (1), the asphalt is heated to 60°C to soften it, then mixed with 0.03 mol / L NaOH alkaline solution, and ultrasonically treated at 60°C for 6 h to obtain a mixture. The asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 20:80.

[0084] The only difference between Example 14 and Example 4 is that in step (1), the asphalt is heated to 60°C to soften it, then mixed with 0.02 mol / L NaOH alkaline solution, and ultrasonically treated at 60°C for 6 h to obtain a mixture. The asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 20:80.

[0085] The only difference between Example 15 and Example 5 is that in step (1), the asphalt is heated to 60°C to soften it, then mixed with 0.01 mol / L NaOH alkaline solution, and ultrasonically treated at 60°C for 6 h to obtain a mixture, wherein the asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 20:80.

[0086] The only difference between Example 16 and Example 1 is that in step (1), the asphalt is heated to 50°C to soften it, then mixed with 0.05 mol / L NaOH alkaline solution, and ultrasonically treated at 50°C for 5 h to obtain a mixture. The asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 20:80.

[0087] The only difference between Example 17 and Example 2 is that in step (1), the asphalt is heated to 50°C to soften it, then mixed with 0.04 mol / L NaOH alkaline solution, and ultrasonically treated at 50°C for 5 h to obtain a mixture. The asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 20:80.

[0088] The only difference between Example 18 and Example 3 is that in step (1), the asphalt is heated to 50°C to soften it, then mixed with 0.03 mol / L NaOH alkaline solution, and ultrasonically treated at 50°C for 5 h to obtain a mixture. The asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 20:80.

[0089] The only difference between Example 19 and Example 4 is that in step (1), the asphalt is heated to 50°C to soften it, then mixed with 0.02 mol / L NaOH alkaline solution, and ultrasonically treated at 50°C for 5 h to obtain a mixture. The asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 20:80.

[0090] The only difference between Example 20 and Example 5 is that in step (1), the asphalt is heated to 50°C to soften it, then mixed with 0.01 mol / L NaOH alkaline solution, and ultrasonically treated at 50°C for 5 h to obtain a mixture. The asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 20:80.

[0091] Comparative Example 1 The preparation method of the negative electrode material of the comparative example includes the following steps: (1) After heating the asphalt to 80°C to soften it, it is mixed with 0.2 mol / L KOH alkaline solution and ultrasonically treated at 80°C for 10 h to obtain a mixture, wherein the asphalt is mainly composed of saturated and aromatic components, and the ratio of saturated to aromatic components is 5:95; (2) The mixture is cooled to room temperature, repeatedly washed and filtered with distilled water until the filtrate is neutral, the solvent is removed by vacuum filtration, and then placed in an oven for vacuum drying for 10 h and crushed to obtain powder (D 50(16.6μm); (3) Carbonize the powder at 1200℃ for 10 h to obtain the precursor; (4) Graphitize the precursor at 3000℃ for 8 h to obtain the graphite anode material.

[0092] Comparative Example 2 The preparation method of the negative electrode material of the comparative example includes the following steps: (1) After heating the asphalt to 70°C to soften it, deionized water is added under the condition of keeping it at 70°C and ultrasonic treatment is performed for 8 h to obtain a mixture, wherein the asphalt is mainly composed of saturated and aromatic components, and the content ratio of saturated and aromatic components is 20:80; (2) The mixture is cooled to room temperature, repeatedly washed and filtered with distilled water until the filtrate is neutral, the solvent is removed by suction filtration, and then placed in an oven for vacuum drying for 10 h, and then shaped to obtain powder (D 50 (16.8μm); (3) Carbonize the powder at 1200℃ for 10h to obtain the precursor; (4) Graphitize the precursor at 3000℃ for 8h to obtain the graphite anode material.

[0093] Test method (1) Test method for particle size of negative electrode material: The particle size distribution range of composite negative electrode material is tested by Malvern laser particle size analyzer.

[0094] (2) Test method for pore volume of negative electrode material: The test was conducted using the ASAP2460 instrument from the American company, Micron Technology. The pore volume V was calculated using the BJH Desorption Cumulative Volume of Pores model within the pore size range of 17 Å to 3000 Å. (3) Test method for specific surface area of ​​negative electrode material: The test was conducted using the JW-DX dynamic specific surface area rapid measuring instrument from Beijing Jingwei Gaobo Science and Technology Co., Ltd. The unit is m. 2 / g.

[0095] (4) Test method for surface morphology of negative electrode material: The surface morphology of negative electrode material particles was observed using a Hitachi S4800 scanning electron microscope.

[0096] (5) Test method for the true density of the negative electrode material: The true density of the material was measured using an Anton Pacanta PENTAPYC 5200e true density meter. The Archimedes principle of gas displacement (density = mass / volume) was applied, and Bohr's law (PV = nRT) was used under certain conditions for inert gases with small molecular diameters to accurately measure the true volume of the material being tested, thereby obtaining its true specific gravity, with the unit being g / cm³. 3 .

[0097] (6) The interlayer spacing d of the (002) plane of the material was characterized by X-ray diffraction. 002The unit is Å. The crystallite size Lc along the c-axis and the peak intensity ratio I between the (004) and (110) planes are obtained by X-ray diffraction. 004 / I 110 .

[0098] (7) Battery performance testing method: The negative electrode materials prepared in Examples 1-20 and Comparative Examples 1-2, carboxymethyl cellulose, conductive carbon black, and styrene-butadiene rubber were magnetically stirred in deionized water at a mass ratio of 95:1.5:1.5:2 for 8 hours to ensure uniform mixing. The resulting slurry was coated onto copper foil and dried under vacuum at 60°C to serve as the working electrode. Lithium metal was used as the counter electrode and reference electrode, Celgard 2325 was used as the separator, and the electrolyte was 1 mol∙L⁻¹ LiPF₆-EC (ethylene carbonate) / DMC (dimethyl carbonate) / EMC (ethyl methyl carbonate) (volume ratio of 1:1:1). The CR2016 button cell was assembled in a glove box filled with high-purity argon gas.

[0099] The initial discharge capacity / initial discharge efficiency test was conducted on a LAND battery tester under the following charging and discharging conditions: rest for 2 hours; discharge: 0.1C to 0.005V, 0.09C, 0.08C…0.02C to 0.001V; rest for 15 minutes; charge: 0.1C to 1.5V; rest for 15 minutes.

[0100] Coin cells were subjected to rate performance testing at 25±2℃ to obtain charge / discharge specific capacity and coulombic efficiency at 0.2C, 1C, and 2C. The charge / discharge conditions for the coin cell rate test were as follows: ① Discharge to 0.01V at 0.1C, hold constant voltage for 5 hours, then charge to 1.5V at 0.1C; ② Discharge to 0.01V at 0.2C, hold constant voltage to 0.01C, then charge to 1.5V at 0.2C; ③ Discharge to 0.01V at 0.2C, hold constant voltage to 0.01C, then charge to 1.5V at 2C; ④ Discharge to 0.01V at 0.2C, hold constant voltage to 0.01C, then charge to 1.5V at 0.2C; ⑤ Discharge to 0.01V at 1C, hold constant voltage to 0.01C, then charge to 1.5V at 0.2C; ⑥ Discharge to 0.01V at 2C.

[0101] Full cell testing: The negative electrode materials prepared in each embodiment were used as negative electrode active materials. The negative electrode active material, conductive agent, binder and dispersant were dissolved in deionized water at a mass percentage of 95.2:1.5:2:1.3, and the solid content was controlled at 50wt%. The mixture was coated on an 8μm thick copper foil current collector and vacuum dried to obtain the negative electrode sheet. Lithium iron phosphate, polyvinylidene fluoride and conductive agent carbon black were mixed with solvent NMP (N-methylpyrrolidone) at a mass ratio of 95:2:3 and coated on a 16μm thick aluminum foil. The mixture was vacuum dried to obtain the positive electrode sheet. The coated positive and negative electrode sheets were processed through sheet preparation, winding, drying, liquid injection, sealing and formation, and capacity testing to produce a 554065 type soft-pack lithium-ion battery.

[0102] The obtained pouch cells were subjected to charge-discharge tests on the LAND battery testing system of Wuhan Jinno Electronics Co., Ltd. Under normal temperature conditions, 1C / 1C current was used for charge-discharge, and the charge-discharge voltage was limited to 3.0V~4.35V. First-cycle efficiency and 500-cycle capacity retention tests were conducted (negative electrode compaction density was 1.60 g / cm³). 3 ).

[0103] The performance test results of the negative electrode materials obtained in the above embodiments are shown in Table 1 below, and the performance test results of the batteries made from the negative electrode materials are shown in Table 2 below: Table 1. Performance Comparison Results of Negative Electrode Materials

[0104]

[0105] Table 2. Battery performance comparison results

[0106]

[0107] According to the test data from Examples 1-20, the formation of pores inside and / or on the surface of the graphite prepared in the embodiments of this application improves the high-rate charging performance of the material. This is because the parameter of the negative electrode material is controlled to be 0.7≤V. With S / D ≤ 3.95 and 89 ≤ G ≤ 93, lithium ions and sufficient carbon atoms can combine under low resistance. Lithium ions diffuse rapidly at the solid-liquid interface and within the solid phase, inhibiting the formation of lithium deposition, reducing concentration polarization, and making full use of the lithium ion diffusion channels of the anode material. This gives the anode material sufficient space for lithium insertion / extraction reactions, which is beneficial for obtaining anode materials with better rate performance and capacity.

[0108] The negative electrode material prepared in Comparative Example 1 had an excessively high concentration of alkaline solution, resulting in excessively large pore volume and specific surface area due to etching. When the S / D ratio deviates from the above range, the pores between the negative electrode material particles are wetted, and a solid electrolyte film is formed on the surface of the negative electrode material particles, while surface lithium storage is formed. A large number of electrolyte lithium ions accumulate on the surface of the graphite particles, causing concentration polarization and forming lithium deposition, which inhibits the diffusion of lithium ions. As a result, electrochemical reactions cannot occur on the particle surface, the "effective electrochemical reaction space" of the negative electrode material decreases, resulting in poor cycle performance of the material.

[0109] The negative electrode material prepared in Comparative Example 2 did not undergo in-situ etching with an alkaline solution during preparation; instead, it was directly graphitized. This resulted in insufficient graphite pores, a small pore volume (V), and a decreased specific surface area. When the S / D ratio falls outside the aforementioned range, lithium ions lack sufficient diffusion channels, resulting in poor rate performance of the material.

[0110] Although this application discloses preferred embodiments as described above, it is not intended to limit the claims. Any person skilled in the art can make several possible changes and modifications without departing from the concept of this application. Therefore, the scope of protection of this application should be determined by the scope defined in the claims of this application.

Claims

1. A negative electrode material, characterized in that, The negative electrode material comprises graphite, and the surface and / or interior of the graphite have pores, the pore volume of the negative electrode material being V cm³. 3 / kg, true density is D g / cm³ 3 Specific surface area is S m 2 / g, graphitization degree is G%, where 0.7≤V S / D≤3.95, while 1.812≤V≤4.987, 0.872≤S≤1.773, 2.238≤D≤2.257, 89≤G≤93; the pore volume was tested using an ASAP2460 instrument from Micron Technology, USA, and calculated using the BJH Desorption Cumulative Volume of Pores model within the pore size range of 17 Å to 3000 Å; the true density was tested using a PENTAPYC 5200e true density meter from Anton Pacanta; the specific surface area was tested using a JW-DX dynamic specific surface area rapid measuring instrument from Beijing Jingwei Gaobo Science and Technology Co., Ltd.

2. The negative electrode material according to claim 1, characterized in that, The negative electrode material satisfies at least one of the following characteristics: (1) V is 1.812, 2.016, 2.582, 2.897, 3.348, 3.476, 3.755, 3.896, 4.013, 4.167, 4.275, 4.512, 4.987 or within the range of any two of the above values; (2) S is 1.773, 1.643, 1.593, 1.532, 1.498, 1.446, 1.386, 1.315 (2) 1.267, 1.157, 1.044, 0.912, 0.872 or within the range of any two of the above values; (3) D is 2.2385, 2.2440, 2.2476, 2.2481, 2.2502, 2.2513, 2.2562 or within the range of any two of the above values; (4) G is 89, 90, 90.5, 91, 91.5, 92, 92.5, 93 or within the range of any two of the above values.

3. The negative electrode material according to claim 1, characterized in that, The negative electrode material satisfies at least one of the following characteristics: (1) the pores include at least one of micropores and mesopores; (2) the graphite is artificial graphite.

4. The negative electrode material according to claim 2, characterized in that, The average pore diameter is 50 Å to 200 Å.

5. The negative electrode material according to claim 1, characterized in that, The interlayer spacing of the (002) plane of the negative electrode material was determined by X-ray diffraction to be d. 002 3.356Å≤d 002 ≤3.364Å.

6. The negative electrode material according to claim 1, characterized in that, The particle size D of the negative electrode material 50 The size ranges from 10μm to 20μm.

7. The negative electrode material according to claim 1, characterized in that, The negative electrode material also includes amorphous carbon, which exists on the graphite surface and / or is dispersed between graphite particles.

8. The negative electrode material according to claim 1, characterized in that, The negative electrode material also includes an amorphous carbon coating layer on the surface of the graphite, the thickness of which is 10 nm to 500 nm.

9. The negative electrode material according to claim 6 or 7, characterized in that, The amorphous carbon accounts for 0.1 wt% to 3 wt% of the mass of the anode material.

10. A battery, characterized in that, The battery includes the negative electrode material according to any one of claims 1 to 9.

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