Carbon material and preparation method, negative electrode material and preparation method, lithium ion battery

Abstract

The application relates to a carbon material and a preparation method, a negative electrode material and a preparation method, and a lithium ion battery, wherein the carbon material has pores, the pores include cylindrical pores, and the proportion of the pore volume of the cylindrical pores accounts for 40-80% of the pore volume of the carbon material. The proportion of the pore volume of the cylindrical pores in the carbon material of the application is relatively high, so that active substances are deposited in the carbon material with relatively determined deposition positions and high pore utilization, and the expansion performance, capacity and initial efficiency of the negative electrode material composed of the active substances and the carbon material can be improved.

Description

Technical Field

[0001] This application belongs to the field of negative electrode material technology, specifically, it relates to carbon materials and their preparation methods, negative electrode materials and their preparation methods, and lithium-ion batteries. Background Technology

[0002] Anode materials are one of the key materials for achieving high capacity and long cycle life in lithium-ion batteries. However, traditional graphite anode materials often have low capacity, while silicon-based anode materials have gradually become popular worldwide due to silicon's high capacity advantage. However, the mechanism of silicon's high capacity is the formation of silicon-lithium alloys with lithium, a process accompanied by a volume expansion of over 300% in the silicon matrix. At the same time, silicon has poor conductivity, which means that pure silicon anode materials often have drawbacks such as high expansion and low initial efficiency, seriously hindering the development of silicon anode materials.

[0003] Porous carbon materials possess abundant pore structures, providing ample space for the volume expansion of silicon materials and suppressing the expansion effect of silicon anode materials. Simultaneously, the carbon framework of porous carbon exhibits excellent electronic conductivity, providing a well-developed conductive network for silicon anode materials, improving their conductivity and enhancing their initial efficiency. In the development of silicon-carbon anode materials, improving the deposition efficiency of silicon in porous carbon is a crucial direction. Existing research typically focuses on improving pore volume, pore size, or silicon deposition time, temperature, and silicon source concentration. However, these research directions cannot effectively address silicon deposition efficiency, nor can they control the silicon deposition location, making it difficult for silicon-carbon anode materials to simultaneously achieve the performance requirements of high capacity, high initial efficiency, and low expansion.

[0004] Therefore, developing a carbon material and anode material with high capacity, high initial efficiency, and low expansion performance remains a technical challenge in this field. Summary of the Invention

[0005] This application provides a carbon material and its preparation method, a negative electrode material and its preparation method, and a lithium-ion battery, which can improve the deposition efficiency of active materials in carbon materials and control the deposition position of active materials in carbon materials, thereby improving the capacity performance and initial efficiency of carbon materials.

[0006] In a first aspect, embodiments of this application provide a carbon material having pores, the pores including cylindrical pores, and the pore volume of the cylindrical pores accounting for 40% to 80% of the pore volume of the carbon material being 100%.

[0007] In some embodiments, the pores further include fissure pores and spherical pores. With the pore volume of the carbon material being 100%, the pore volume of the spherical pores accounts for 5% to 55%, and the pore volume of the fissure pores accounts for 5% to 55%.

[0008] In some embodiments, the carbon material includes at least one of hard carbon, soft carbon, graphite, mesophase carbon microspheres, activated carbon, and carbon gel.

[0009] In some embodiments, the median particle size of the carbon material is 5 μm to 25 μm.

[0010] In some embodiments, the specific surface area of ​​the carbon material is 900 m². 2 / g ~2000 m 2 / g.

[0011] In some embodiments, the total pore volume of the carbon material is 0.3 cm³. 3 / g~1.0 cm 3 / g.

[0012] Secondly, embodiments of this application provide a negative electrode material, including the carbon material described in the first aspect. The negative electrode material further includes an active substance, which is at least partially distributed within the pores. With the pore volume of the negative electrode material being 100%, the pore volume ratio of the cylindrical pores in the negative electrode material is less than 10%, the pore volume ratio of the spherical pores in the negative electrode material is 35% to 95%, and the pore volume ratio of the fissure pores in the negative electrode material is 5% to 65%.

[0013] In some embodiments, with the pore volume of the negative electrode material after removing the active material being 100%, the pore volume ratio of the cylindrical pores is 40% to 80%, the pore volume ratio of the spherical pores is 5% to 55%, and the pore volume ratio of the slit pores is 5% to 55%.

[0014] In some embodiments, the active substance includes at least one selected from Li, Na, K, Sn, Ge, Si, Fe, Mg, SiO, Ti, Zn, Al, P, and Cu.

[0015] In some embodiments, the active material includes a silicon-based material, which includes at least one of amorphous silicon, crystalline silicon, silicon oxide, silicon alloy, and a composite of crystalline and amorphous silicon.

[0016] In some embodiments, the median particle size of the silicon-based material is 1 nm to 10 nm.

[0017] In some embodiments, the mass percentage of silicon in the negative electrode material is 35% to 55%.

[0018] In some embodiments, the negative electrode material further includes a coating layer distributed on at least a portion of the surface of the carbon material.

[0019] In some embodiments, the negative electrode material further includes a coating layer distributed on at least a portion of the surface of the carbon material, the coating layer comprising a carbon layer, the carbon layer being made of at least one of graphene, soft carbon, hard carbon, and conductive polymer.

[0020] In some embodiments, the negative electrode material further includes a coating layer distributed on at least a portion of the surface of the carbon material, the coating layer comprising a metal oxide layer, the metal oxide layer being made of at least one of titanium oxide, aluminum oxide, lithium oxide, cobalt oxide, and vanadium oxide.

[0021] In some embodiments, the negative electrode material further includes a coating layer distributed on at least a portion of the surface of the carbon material, the coating layer comprising a nitride layer, the nitride layer being made of at least one of titanium nitride, vanadium nitride, cobalt nitride, nickel nitride, and carbon nitride.

[0022] In some embodiments, the thickness of the coating layer is 0.1 nm to 100 nm.

[0023] In some embodiments, the median particle size of the negative electrode material is 5 μm to 30 μm.

[0024] In some embodiments, the average pore size of the pores in the negative electrode material is 3 nm to 20 nm.

[0025] In some embodiments, the specific surface area of ​​the negative electrode material is 1m². 2 / g ~100 m 2 / g.

[0026] In some embodiments, the total pore volume of the negative electrode material is 0.005 cm³. 3 / g~0.2 cm 3 / g.

[0027] In some embodiments, the compaction density of the negative electrode material is 0.8 g / cm³. 3 ~1.2 g / cm 3 .

[0028] Thirdly, embodiments of this application provide a carbon material, comprising the following steps: In an alkaline environment, carbon-based raw materials and pore-forming agents are mixed to obtain a precursor, wherein the pore-forming agent comprises a water-soluble zinc salt, a silicon oxide, and an alkaline substance, the mass ratio of the carbon-based raw material to the water-soluble zinc salt is 8:(1~7), the mass ratio of the carbon-based raw material to the silicon oxide is 8:(0~3), and the mass ratio of the carbon-based raw material to the alkaline substance is 8:(0~3). The precursor is subjected to carbonization and acid washing to obtain carbon material.

[0029] In some embodiments, mixing the carbon-based raw material and the pore-forming agent in an alkaline environment includes mixing the carbon-based raw material, the pore-forming agent, the alkaline reagent, and the solvent for 6 to 12 hours.

[0030] In some embodiments, the mixing is carried out under stirring conditions.

[0031] In some embodiments, the alkaline reagent includes at least one of ammonia, triethylamine, triethanolamine, and ethylenediamine.

[0032] In some embodiments, the solvent includes at least one of deionized water, methanol, and ethanol.

[0033] In some embodiments, the carbon-based raw material includes one of asphalt, epoxy resin, phenolic resin, and ion exchange resin.

[0034] In some embodiments, the water-soluble zinc salt includes at least one of zinc acetate, zinc gluconate, zinc nitrate, zinc sulfate, and zinc chloride.

[0035] In some embodiments, the silicon oxide includes at least one of tetraethoxysilane, methyltriethoxysilane, tetramethoxysilane, and methyltrimethoxysilane.

[0036] In some embodiments, the alkaline substance includes at least one selected from sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, and rubidium hydroxide.

[0037] In some embodiments, the process of mixing the carbon-based raw material and the pore-forming agent further includes drying the mixture obtained from the mixture.

[0038] In some embodiments, the drying temperature is 60°C to 100°C.

[0039] In some embodiments, after mixing the base material and the pore-forming agent, the mixture further includes drying the material obtained by mixing the carbon-based base material and the pore-forming agent for a period of 6 to 12 hours.

[0040] In some embodiments, the carbonization temperature is 600°C to 1000°C.

[0041] In some embodiments, the carbonization process takes 2 to 6 hours.

[0042] In some embodiments, the carbonization process is carried out in a protective gas atmosphere.

[0043] In some embodiments, the flow rate of the protective gas is 50 sccm to 500 sccm.

[0044] In some embodiments, the step of pulverizing the carbonized material obtained from the carbonization process and before the pickling process is further included after carbonizing the precursor.

[0045] In some embodiments, the pulverization process includes at least one of grinding, mechanical pulverization, and air jet milling.

[0046] In some embodiments, the pulverization process takes 5 to 60 minutes.

[0047] In some embodiments, the median particle size of the material obtained from the pulverization process is 5 μm to 25 μm.

[0048] In some embodiments, the pickling process includes: subjecting the carbonization material to a first water wash, a pickling process, and a second water wash.

[0049] In some embodiments, the acid used for pickling includes at least one of hydrofluoric acid, hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid.

[0050] In some embodiments, the concentration of the acid solution used for pickling is 0.1 mol / L to 2 mol / L.

[0051] In some embodiments, the pickling process includes: subjecting the carbonized material to a first water wash, an acid wash, and a second water wash, wherein the first water wash lasts for 2 to 6 hours.

[0052] In some embodiments, the pickling time is 6h to 12h.

[0053] In some embodiments, the secondary washing time is 2 hours to 6 hours.

[0054] Fourthly, embodiments of this application provide a method for preparing a negative electrode material, comprising the following steps: A carbon material is provided, wherein the carbon material is prepared by the preparation method described in the third aspect; The carbon material is vapor-deposited using a vapor-phase active material precursor to obtain the anode material.

[0055] In some embodiments, the gaseous active material precursor includes a gaseous silicon source.

[0056] In some embodiments, the gaseous silicon source includes at least one of silane, ethoxysilane, dichlorosilane, and trichlorosilane.

[0057] In some embodiments, the flow rate of the gaseous active material precursor is 20 sccm to 100 sccm.

[0058] In some embodiments, the temperature of the vapor deposition is 500°C to 650°C.

[0059] In some embodiments, the heating rate of the vapor deposition is 50°C / h to 800°C / h.

[0060] In some embodiments, the vapor deposition time is 1 hour to 10 hours.

[0061] In some embodiments, an auxiliary carrier gas is also added during the vapor deposition process.

[0062] In some embodiments, an auxiliary carrier gas is added during the vapor deposition process, the auxiliary carrier gas including at least one of nitrogen, helium and argon.

[0063] In some embodiments, the flow rate of the auxiliary carrier gas is 50 sccm to 200 sccm.

[0064] In some embodiments, the flow rate ratio of the gaseous silicon source to the auxiliary carrier gas is (5~80):(50~200).

[0065] In some embodiments, the process of vapor-depositing the carbon material using a vapor-phase active material precursor further includes mixing the vapor-deposited material and the coating material and then subjecting them to heat treatment.

[0066] In some embodiments, the coating material includes at least one of a carbon source, a metal oxide, and a nitride.

[0067] In some embodiments, the carbon source includes at least one of a gaseous carbon source and a solid carbon source.

[0068] In some embodiments, the gaseous carbon source includes at least one selected from acetylene, methane, propylene, benzene, ethanol, methanol, ethylene, propane, and butane.

[0069] In some embodiments, the flow rate of the gaseous carbon source is 0.1 L / min to 100 L / min.

[0070] In some embodiments, the solid carbon source includes at least one selected from sucrose, fructose, glucose, pitch, phenolic resin, polyimide, citric acid, epoxy resin, amino resin, polystyrene, polyacrylic acid, carboxymethyl cellulose, and cellulose acetate butyrate.

[0071] In some embodiments, the mass ratio of the solid carbon source to the negative electrode material is (1~100):100.

[0072] In some embodiments, the metal oxide includes at least one of iron oxide, zinc oxide, tin oxide, copper oxide, and titanium oxide.

[0073] In some embodiments, the nitride includes at least one of tin sulfide, molybdenum sulfide, titanium sulfide, iron sulfide, and copper sulfide.

[0074] In some embodiments, the temperature of the heat treatment is 300°C to 1100°C.

[0075] In some embodiments, the heat treatment holding time is 2h to 10h.

[0076] Fifthly, embodiments of this application provide a lithium-ion battery, the lithium-ion battery comprising the negative electrode material described in the second aspect or the negative electrode material prepared by the preparation method described in the fourth aspect.

[0077] The technical solution of this application has at least the following beneficial effects: The carbon material of this application has pores, including cylindrical pores. The pore volume of the cylindrical pores in the carbon material accounts for 40% to 80%, indicating that the carbon material has abundant cylindrical pores. The two ends of the cylindrical pores have open channels, and their morphology is similar to a cylinder (hollow cylinder). The open channels of the cylindrical pores are conducive to gas convection, which can improve the filling efficiency of active materials in the carbon material. Moreover, the cylindrical morphology of the cylindrical pores provides sufficient surface energy, which allows the active materials to be tightly adsorbed into the cylindrical pores under the action of sufficient surface energy, promoting the deposition of active materials in the cylindrical pores and improving the deposition amount and deposition efficiency of active materials in the carbon material. In addition, the presence of cylindrical pores can provide a large amount of space for the volume expansion of active materials, reduce the pulverization of carbon material particles, and thus improve the expansion performance, capacity, and initial efficiency of the carbon material. Attached Figure Description

[0078] The present application will be further described below with reference to the accompanying drawings and embodiments.

[0079] Figure 1 This is a schematic diagram of the structure of the fissure hole in this application; Figure 2 This is a schematic diagram of the cylindrical hole structure of this application; Figure 3 This is a schematic diagram of the spherical hole structure in this application; Figure 4 This is a flowchart illustrating the preparation process of the carbon material in this application; Figure 5 This is a pore size distribution diagram of the carbon material prepared in Example 10 of this application; Figure 6 This is a pore size distribution diagram of the negative electrode material prepared in Example 10 of this application; Figure 7 This is a cumulative pore size distribution diagram of the carbon material in Example 10 of this application; Figure 8This is a cumulative pore size distribution diagram of the negative electrode material in Embodiment 10 of this application. Detailed Implementation

[0080] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0081] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0082] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0083] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0084] This application provides a carbon material having pores, including cylindrical pores. The pore volume of the carbon material is 100%, and the pore volume of the cylindrical pores accounts for 40% to 80%.

[0085] In the above-mentioned scheme, the carbon material of this application has pores, including cylindrical pores. The pore volume ratio of cylindrical pores in the carbon material is 40%~80%, indicating that the carbon material has abundant cylindrical pores. The two ends of the cylindrical pores have open channels, and their morphology is similar to a cylinder (hollow cylinder). The open channels of the cylindrical pores are conducive to gas convection, which can improve the filling efficiency of active materials in the carbon material. Moreover, the cylindrical morphology of the cylindrical pores gives them sufficient surface energy, which allows the active materials to be tightly adsorbed into the cylindrical pores under the action of sufficient surface energy, promoting the deposition of active materials in the cylindrical pores and improving the deposition amount and deposition efficiency of active materials in the carbon material. In addition, the presence of cylindrical pores can provide a large amount of space for the volume expansion of active materials, reduce the pulverization of carbon material particles, and thus improve the expansion performance, capacity and initial efficiency of the carbon material.

[0086] In some embodiments, the pores also include fissure pores and spherical pores. With the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores is 5% to 55%, and the pore volume ratio of fissure pores is 5% to 55%. In some embodiments, the carbon material has three pore morphologies: cylindrical pores, fissure pores, and spherical pores, such as... Figure 1 The diagram shows a schematic of a fractured pore structure. A fractured pore refers to a space in carbon material formed by interparticle contact or stacking. It has open channels at both ends, and the width of the channels is relatively narrow, typically 2-3 times the interlayer spacing of graphite (0.34 nm). Its structure is similar to the interlayer structure of graphite. Figure 2 The diagram shows a schematic of a cylindrical pore structure. A cylindrical pore refers to a pore with a shape resembling a cylinder (hollow cylinder), having channels open at both ends. The cylindrical morphology of the pore provides sufficient surface energy, allowing active substances to be tightly adsorbed into the pore under the influence of sufficient surface energy. Figure 3 The diagram shows a schematic of a spherical pore structure. A spherical pore refers to a pore structure with a shape resembling a sphere, having an open channel at only one end. The neck of a spherical pore is often narrow, and its high surface energy causes active materials to preferentially distribute there, leading to channel blockage and affecting the distribution of active materials within the pore. This application controls the pore volume ratio of cylindrical pores, fissure pores, and spherical pores in the carbon material. The cylindrical pores account for a larger proportion, while the fissure and spherical pores account for a smaller proportion. This ensures that when active materials are deposited in the carbon material, they are mainly distributed within the cylindrical pores, with less distribution in the spherical and fissure pores. This results in a relatively definite distribution of active materials within the carbon material, improving the deposition efficiency and consequently enhancing the expansion performance, capacity, and initial efficiency of the anode material composed of the carbon material and active materials.

[0087] In some embodiments, taking the pore volume of the carbon material as 100%, the pore volume ratio of cylindrical pores is 40% to 80%, specifically 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%, etc., and other values ​​within the above range are also possible, without limitation. The pore volume ratio of spherical pores is 5% to 55%, specifically 5%, 10%, 20%, 30%, 40%, 50%, or 55%, etc., and other values ​​within the above range are also possible, without limitation in this application. The pore volume ratio of fissure pores is 5% to 55%, specifically 5%, 10%, 20%, 30%, 40%, 50%, or 55%, etc., and other values ​​within the above range are also possible, without limitation in this application.

[0088] In some embodiments, the carbon material includes at least one of hard carbon, soft carbon, graphite, mesophase carbon microspheres, activated carbon, and carbon gel.

[0089] In some embodiments, the median particle size of the carbon material is 5μm to 25μm, specifically 5μm, 8μm, 10μm, 12μm, 15μm, 18μm, 20μm, 22μm or 25μm, etc. Of course, it can also be other values ​​within the above range, which are not limited here.

[0090] In some embodiments, the specific surface area of ​​the carbon material is 900 m². 2 / g~2000 m 2 / g, specifically 900 m 2 / g, 1000 m 2 / g、1100 m 2 / g、1200 m 2 / g、1300 m 2 / g, 1400 m 2 / g, 1500 m 2 / g、1600 m 2 / g、1700 m 2 / g、1800 m 2 / g、1900 m 2 / g or 2000 m 2 / g, etc., and of course, other values ​​within the above range are also possible, which are not limited herein. Within the above range, the volume expansion of carbon materials can be suppressed, which is beneficial to improving the cycle performance of the negative electrode material composed of carbon materials and active substances.

[0091] In some embodiments, the total pore volume of the carbon material is 0.3 cm³. 3 / g~1.0 cm 3 / g, specifically 0.3cm 3 / g, 0.4 cm 3 / g, 0.5 cm 3 / g, 0.6 cm 3 / g, 0.65 cm 3 / g, 0.7 cm 3 / g, 0.75 cm 3 / g, 0.8 cm 3 / g, 0.85 cm 3 / g, 0.9 cm 3 / g, 0.95 cm 3 / g or 1.0 cm 3 / g, etc., can also be other values ​​within the above range, and this application does not impose any limitations on them. Within the above range, it indicates that the carbon material of this application has a high pore volume and a stable, non-collapsed structure, which is beneficial for depositing more silicon material and improving the capacity and cycle performance of the anode material composed of carbon material and active material. Preferably, the total pore volume of the carbon material is 0.6 cm³. 3 / g~1.0 cm 3 / g.

[0092] This application provides a negative electrode material, which includes the carbon material described above. The negative electrode material also includes an active substance, which is at least partially distributed in the pores. With the pore volume of the negative electrode material as 100%, the pore volume ratio of cylindrical pores in the negative electrode material is less than 10%, the pore volume ratio of spherical pores in the negative electrode material is 35% to 95%, and the pore volume ratio of fissure pores in the negative electrode material is 5% to 65%. Thus, in this application, the pore volume ratio of cylindrical pores in the carbon material is 40%~80%, while the pore volume ratio of cylindrical pores in the negative electrode material obtained by filling the carbon material with active material is less than 10%. The difference in the pore volume ratio of cylindrical pores before and after filling the carbon material with active material is significant, and the pore volume of cylindrical pores decreases sharply after filling the carbon material with active material. That is, the carbon material has abundant cylindrical pores with open channels at both ends, and its morphology is similar to a cylinder (hollow cylinder). The open channels of the cylindrical pores are conducive to gas convection, which can improve the filling efficiency of active material in the carbon material. Moreover, the cylindrical morphology of the cylindrical pores gives them sufficient surface energy, which allows the active material to be tightly adsorbed into the cylindrical pores under the action of sufficient surface energy, promoting the deposition of active material in the cylindrical pores and improving the deposition amount and deposition efficiency of active material in the negative electrode material. The pore volume ratio of spherical pores in carbon materials ranges from 5% to 55%. In anode materials obtained by filling carbon materials with active materials, the pore volume ratio of spherical pores ranges from 35% to 95%. The difference in the pore volume ratio of spherical pores before and after filling carbon materials with active materials is significant, and the pore volume ratio of spherical pores increases substantially after filling with active materials, indicating that the amount of active material filling the spherical pores is very small. Similarly, the pore volume ratio of fissure pores in carbon materials ranges from 5% to 55%. In anode materials obtained by filling carbon materials with active materials, the pore volume ratio of fissure pores ranges from 5% to 65%. The difference in the pore volume ratio of fissure pores before and after filling carbon materials with active materials is not significant, indicating that the amount of active material filling the anode material is relatively small. The negative electrode material of this application exhibits the highest porosity utilization for filling active material in cylindrical pores, followed by fissure pores, with spherical pores being the least efficient. This means the active material primarily fills the cylindrical pores, followed by the fissure pores, and the spherical pores contain the least amount. Furthermore, the active material has a relatively defined deposition location within the negative electrode material, which is beneficial for increasing the amount of active material filled, thereby improving the capacity and initial efficiency of the negative electrode material. The three specific pore types in the negative electrode material provide ample space for the volume expansion of the active material, reducing particle pulverization and improving the conductivity of the negative electrode material, thus enhancing its expansion performance, capacity, and initial efficiency.

[0093] In some embodiments, taking the pore volume of the negative electrode material as 100%, the pore volume ratio of the fissure pores in the negative electrode material is 5% to 65%. Specifically, it can be 5%, 10%, 20%, 25%, 35%, 40%, 50%, or 65%, etc., and other values ​​within the above range are also possible and are not limited here. The small difference in the pore volume ratio of the fissure pores before and after filling the negative electrode material with active material indicates that the amount of active material deposited in the fissure pores is relatively small. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of the cylindrical pores in the negative electrode material is less than 10%, specifically, it can be 1%, 3%, 5%, 7%, 8%, 9%, or 9.5%, etc., and other values ​​within the above range are also possible and are not limited here. Within the aforementioned range, it indicates that the negative electrode material has abundant and appropriately sized cylindrical pores before being filled with active material. After the negative electrode material is filled with active material, most of the cylindrical pores are filled with active material, leaving only a small portion of pores. This indicates a high filling amount of active material in the cylindrical pores of the negative electrode material, which is beneficial for improving the capacity and initial efficiency of the negative electrode material. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores in the negative electrode material is 35%~95%, specifically 35%, 45%, 55%, 65%, 75%, 80%, 85%, or 95%, etc., and of course, other values ​​within the above range are also possible and are not limited here. The difference in the pore volume ratio of spherical pores before and after the active material is filled with negative electrode material is significant, and the pore volume ratio of spherical pores increases substantially after the active material is filled, indicating that the filling amount of active material in spherical pores is the least compared to cylindrical pores and fissure pores.

[0094] In some embodiments, taking the pore volume of the negative electrode material after removing active material as 100%, the pore volume ratio of the fissure pores is 5% to 55%, specifically it can be 5%, 10%, 20%, 25%, 35%, 40%, 50%, or 55%, etc., and other values ​​within the above range are also possible and are not limited here. The pore volume ratio of the cylindrical pores is 40% to 80%, specifically it can be 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%, etc., and other values ​​within the above range are also possible and are not limited here. The pore volume ratio of the spherical pores is 5% to 55%, specifically it can be 5%, 10%, 20%, 25%, 35%, 40%, 50%, or 55%, etc., and other values ​​within the above range are also possible and are not limited here. The pore volume ratio of the aforementioned slit pores, the volume ratio of cylindrical pores, and the volume ratio of spherical pores are pore volume ratios measured after etching the active material in the negative electrode material. Taking silicon-based material as an example, the pore volume ratio of each pore can be measured after etching the negative electrode material with hydrofluoric acid.

[0095] In some embodiments, the active material is also distributed on at least a portion of the surface of the carbon material.

[0096] In some embodiments, the active material refers to a substance that can react with lithium to perform lithium intercalation / deintercalation. The active material includes at least one selected from Li, Na, K, Sn, Ge, Si, Fe, Mg, SiO, Ti, Zn, Al, P, and Cu, and can be a metallic element. In some embodiments, the active material can specifically be Si particles, Sn particles, Ge particles, or Al particles. In other embodiments, the active material can also be a lithium-silicon alloy, a magnesium-silicon alloy, etc. It should be noted that in some cases, the active material includes both elemental particles and alloys.

[0097] In some embodiments, the active material includes a silicon-based material, which includes at least one of amorphous silicon, crystalline silicon, silicon oxide, silicon alloy, and a composite of crystalline and amorphous silicon. Silicon oxide materials include silicon oxide (SiO₂). x Where 0 < x ≤ 2, silicon oxide is a silicon-oxygen complex containing oxygen atoms and silicon atoms, with a molar ratio of oxygen atoms to silicon atoms of 0 to 2, excluding 0. It can be Si, SiO₂, etc. 0.2 SiO 0.5 SiO 0.8 SiO, SiO 1.2 SiO 1.5 SiO 1.8 It may be a substance composed of two or more of the following: SiO2, or a substance with the chemical formula SiO2. x The compounds can, of course, be other values ​​within the above range, and this application does not impose any limitations on them. Silicon alloys can be silicon-lithium alloys, silicon-magnesium alloys, etc. It should be noted, however, that in some cases, silicon alloys include elemental silicon particles and alloys.

[0098] In some embodiments, the silicon-based material is amorphous silicon. It is understood that amorphous silicon expands isotropically during lithium intercalation, which can reduce the collapse of the pore structure in the anode material, suppress the rapid decay of the specific capacity of the anode material, and improve the lithium intercalation cycle performance of the anode material.

[0099] In some embodiments, the median particle size of the silicon-based material is 1 nm to 10 nm, specifically 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm or 10 nm, etc. Of course, it can also be other values ​​within the above range, which are not limited here.

[0100] In some implementations, the mass percentage of silicon-based material in the anode material is 35% to 55%, specifically 35%, 38%, 40%, 43%, 45%, 48%, 50%, 53%, or 55%, etc. Of course, other values ​​within the above range are also possible, and no limitation is made here.

[0101] In some embodiments, the median particle size of the negative electrode material is 5μm to 30μm, specifically 5μm, 10μm, 15μm, 20μm, 25μm, or 30μm, etc., and of course, other values ​​within the above range are also possible, which are not limited here. Controlling the median particle size of the negative electrode material within the above range is beneficial to improving the cycle performance of the negative electrode material.

[0102] In some embodiments, the average pore size of the pores in the negative electrode material is 3nm to 20nm, specifically 3nm, 5nm, 8nm, 10nm, 12nm, 15nm, 18nm, or 20nm, etc., and of course, other values ​​within the above range are also possible and are not limited here. Within the above range, it is beneficial to increase the deposition amount of active material in the negative electrode material, thereby improving the capacity and first-pass efficiency of the negative electrode material.

[0103] In some implementations, the specific surface area of ​​the negative electrode material is 1m². 2 / g ~100m 2 / g, specifically 1m 2 / g, 10m 2 / g、20 m 2 / g、30 m 2 / g、40 m 2 / g、50 m 2 / g、60 m 2 / g、70 m 2 / g、80 m 2 / g、90 m 2 / g or 100 m 2 / g, etc., can also be other values ​​within the above range, and are not limited here. Within the above range, reducing the formation of SEI during the lithium insertion / deintercalation process of the anode material is beneficial to improving the initial efficiency of the anode material.

[0104] In some embodiments, the total pore volume of the negative electrode material is 0.005 cm³. 3 / g~0.2 cm 3 / g, specifically 0.005 cm 3 / g, 0.01 cm 3 / g, 0.03 cm 3 / g, 0.05 cm 3 / g, 0.08 cm 3 / g, 0.1 cm 3 / g, 0.15 cm 3 / g or 0.2 cm 3 / g, etc., can also be other values ​​within the above range, and are not limited here. Within the above-mentioned range, the total pore volume of the negative electrode material of this application is small, indicating that the negative electrode material is filled with a large amount of active material, which is beneficial to the improvement of the capacity and first-time efficiency of the negative electrode material.

[0105] In some embodiments, the compaction density of the negative electrode material is 0.8 g / cm³. 3 ~1.2 g / cm 3 Specifically, it could be 0.8 g / cm³. 3 0.85 g / cm 3 0.9 g / cm 3 0.95 g / cm 3 1.0 g / cm 3 1.05 g / cm 3 1.1 g / cm 3 Or 1.2 g / cm 3 Of course, other values ​​within the above range are also possible and are not limited here. Within the above range, it is beneficial to improve the structural stability and processing performance of the anode material.

[0106] In some embodiments, the negative electrode material further includes a coating layer distributed on at least a portion of the surface of the carbon material. The coating layer serves two purposes: firstly, it reduces the risk of electrolyte entering the negative electrode material and causing side reactions that could lead to a decrease in initial efficiency and capacity; secondly, the coating layer can work synergistically with the carbon material to mitigate the volume expansion of silicon, thereby reducing the overall volume expansion of the negative electrode material and minimizing electrode sheet swelling.

[0107] In some embodiments, the coating layer is at least one of a carbon layer, a metal oxide layer, and a nitride layer.

[0108] In some embodiments, the carbon layer is made of at least one of graphene, soft carbon, hard carbon, and conductive polymers. Specifically, the conductive polymers include at least one of polyaniline, polyacetylene, polypyrrole, polythiophene, poly-3-hexylthiophene, poly(p-phenylenevinylene), polypyridine, and polyphenylenevinylene.

[0109] In some embodiments, the metal oxide layer is made of at least one of titanium oxide, aluminum oxide, lithium oxide, cobalt oxide, and vanadium oxide.

[0110] In some embodiments, the nitride layer is made of at least one of titanium nitride, vanadium nitride, cobalt nitride, nickel nitride, and carbon nitride.

[0111] In some embodiments, the thickness of the coating layer is 0.1 nm to 100 nm, specifically 0.1 nm, 1 nm, 10 nm, 30 nm, 50 nm, 70 nm, 90 nm and 100 nm, etc., and of course other values ​​within the above range are also possible, which are not limited here.

[0112] This application provides a method for preparing carbon materials, such as... Figure 4 The diagram shown is a flowchart of the preparation process of the carbon material of this application, which includes the following steps: Step S100: In an alkaline environment, carbon-based raw materials and pore-forming agents are mixed to obtain a precursor. The pore-forming agent includes water-soluble zinc salt, silicon oxide and alkaline substances. The mass ratio of carbon-based raw materials to water-soluble zinc salt is 8:(1~7), the mass ratio of carbon-based raw materials to silicon oxide is 8:(0~3), and the mass ratio of carbon-based raw materials to alkaline substances is 8:(0~3). Step S200: Carbonize the precursor and acid wash the carbonized material to obtain carbon material.

[0113] In the above scheme, under alkaline conditions, this application creates pores in the carbon-based raw material by mixing a carbon-based raw material and a pore-forming agent, forming three different pore structures. The pore-forming agent includes water-soluble zinc salt, silicon oxide, and an alkaline substance. The mass ratio of carbon-based raw material to water-soluble zinc salt is 8:(1~7), the mass ratio of carbon-based raw material to silicon oxide is 8:(0~3), and the mass ratio of carbon-based raw material to alkaline substance is 8:(0~3). Further carbonization and acid washing processes result in three pore structures in the obtained carbon material: cylindrical pores, spherical pores, and fissure pores. Among them, spherical pores account for 5%~55% of the pore volume in the carbon material, fissure pores account for 5%~55% of the pore volume in the carbon material, and cylindrical pores account for 40%~80% of the pore volume in the carbon material. The carbon material of this application has a higher proportion of cylindrical pores, which is beneficial for filling the active material within the carbon material and improving the deposition efficiency of the active material. Moreover, by controlling the proportions of cylindrical pores, fissure pores, and spherical pores in the carbon material, this application helps to determine the deposition location of the active material in the carbon material, improving the capacity performance of the negative electrode material composed of carbon material and active material. Simultaneously, the three types of pores in the carbon material provide ample space for the volume expansion of the active material, reducing the pulverization of carbon material particles and improving the conductivity of the carbon material, thereby improving the expansion performance, capacity, and initial efficiency of the carbon material. This application obtains a carbon material with abundant pores by controlling the type of activator and the addition ratio of carbon-based raw materials and activators. The process is simple, can be mass-produced, and can improve the electrochemical performance of carbon materials as batteries.

[0114] In this application, carbon-based raw materials and water-soluble zinc salts are hydrolyzed in an alkaline solvent to generate rod-shaped zinc oxide, which is then removed by acid washing to form cylindrical pores. Silicon oxide compounds react with carbon-based raw materials to hydrolyze and generate spherical silicon oxide, which is then removed by acid washing to obtain spherical pores. An alkaline compound acts as an ionic template, reacting with the carbon-based raw materials to form salts, which are then acid-washed to obtain cracked pores. It is understood that when the mass ratio of carbon-based raw materials to silicon oxides is 8:0, no silicon oxide pore-forming agent is added; similarly, when the mass ratio of carbon-based raw materials to alkaline substances is 8:0, no alkaline pore-forming agent is added. It is also understood that when the pore-forming agent consists only of water-soluble zinc salts, cracked pores and spherical pores will inevitably be generated during the carbonization and acid washing processes.

[0115] The preparation method of this application is described in detail below with reference to the embodiments: Step S100: In an alkaline environment, carbon-based raw materials and pore-forming agents are mixed to obtain a precursor. The pore-forming agent includes water-soluble zinc salt, silicon oxide and alkaline substances. The mass ratio of carbon-based raw materials to water-soluble zinc salt is 8:(1~7), the mass ratio of carbon-based raw materials to silicon oxide is 8:(0~3), and the mass ratio of carbon-based raw materials to alkaline substances is 8:(0~3).

[0116] In some embodiments, mixing the carbon-based raw material and the pore-forming agent in an alkaline environment includes mixing the carbon-based raw material, the pore-forming agent, the alkaline reagent, and the solvent for 6 to 12 hours.

[0117] In some embodiments, mixing is carried out under stirring conditions. Stirring helps the carbon-based raw materials and pore-forming agents to be fully and uniformly mixed, which is beneficial for the subsequent formation of a uniformly distributed pore structure on the carbon-based raw materials by the pore-forming agent, and also helps to improve the structural stability of the carbon materials.

[0118] In some embodiments, the carbon-based raw material includes one of asphalt, epoxy resin, phenolic resin, and ion exchange resin.

[0119] In some embodiments, the alkaline reagent includes at least one of ammonia, triethylamine, triethanolamine, and ethylenediamine.

[0120] In some embodiments, the solvent includes at least one of deionized water, methanol, and ethanol.

[0121] In some embodiments, the water-soluble zinc salt includes at least one of zinc acetate, zinc gluconate, zinc nitrate, zinc sulfate, and zinc chloride. The water-soluble zinc salt can undergo a hydrolysis reaction in an alkaline environment to generate rod-shaped zinc oxide, which is beneficial for the subsequent formation of cylindrical pores.

[0122] In some embodiments, the mass ratio of carbon-based raw material to water-soluble zinc salt is 8:(1~7), specifically 8:1, 8:2, 8:3, 8:4, 8:5, 8:6, or 8:7, etc., and of course, other values ​​within the above range are also possible, which are not limited herein. If too much water-soluble zinc salt is added, more cylindrical pores will be formed, which can easily lead to the collapse of the carbon material structure, which is not conducive to improving the structural stability of the carbon material. Moreover, excessive deposition of active material in the cylindrical pores will result in poor uniformity of distribution of active material in the carbon material, which can easily lead to agglomeration of active material deposited in the carbon material. The volume expansion of carbon during charge and discharge is large, resulting in reduced cycle performance. If too little water-soluble zinc salt is added, less active material can be deposited in the carbon material, which is not conducive to improving the capacity of the carbon material.

[0123] In some embodiments, the silicon oxide includes at least one of tetraethoxysilane, methyltriethoxysilane, tetramethoxysilane, and methyltrimethoxysilane.

[0124] In some embodiments, the alkaline substance includes at least one of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, and rubidium hydroxide. The aforementioned pore-forming agent, acting as an ionic template agent, is dispersed in the carbon material in ionic form and forms nanoscale carbonates during subsequent treatment. Simultaneously, nanoscale alkaline substances, nanoscale elemental metals, CO2, CO, and H2 are slowly generated. Subsequent acid washing removes these substances, thereby forming pores.

[0125] In some embodiments, the mass ratio of carbon-based raw materials to silicon oxide is 8:(0~3), specifically 8:0, 8:0.1, 8:0.5, 8:1, 8:1.5, 8:2, 8:2.5, or 8:3, etc., and of course, other values ​​within the above range are also possible, which are not limited herein. If too much silicon oxide pore-forming agent is added, more spherical pores will be formed subsequently, which can easily lead to the collapse of the carbon material structure, which is not conducive to improving the structural stability of the carbon material. Moreover, more spherical pores are not conducive to the deposition of active materials in the pores, resulting in too low deposition efficiency of active materials, which is not conducive to improving the capacity and initial efficiency of carbon materials.

[0126] In some embodiments, the mass ratio of carbon-based raw material to alkaline substance is 8:(0~3), specifically 8:0, 8:0.1, 8:0.5, 8:1, 8:1.5, 8:2, 8:2.5, or 8:3, etc., and of course, other values ​​within the above range are also possible, which are not limited herein. If too much alkaline pore-forming agent is added, more fissures and pores will be formed, which is not conducive to the deposition of active material in the pores, resulting in too low deposition efficiency of active material and is not conducive to improving the capacity of carbon material.

[0127] This application obtains a carbon material with abundant pores by adjusting the addition ratio of carbon-based raw materials and three different activators, and then deposits active materials in the pores. This helps to determine the deposition position of active materials in carbon materials and improves the deposition efficiency of active materials, thereby enhancing the electrochemical performance of carbon materials as batteries.

[0128] In some embodiments, the process after mixing further includes drying the resulting mixture.

[0129] In some embodiments, the drying temperature is 60°C to 100°C, specifically 60°C, 70°C, 80°C, 90°C or 100°C, etc., and of course, other values ​​within the above range are also possible, which are not limited here.

[0130] In some embodiments, the drying time is 6h to 12h, specifically 6h, 7h, 8h, 9h, 10h, 11h or 12h, etc., and of course other values ​​within the above range are also possible, which are not limited here.

[0131] Step S200: The precursor is subjected to carbonization and acid washing to obtain carbon material.

[0132] In some embodiments, the carbonization temperature is 600℃~1000℃, specifically 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, 900℃ or 1000℃, etc., and of course other values ​​within the above range are also possible, which are not limited here.

[0133] In some embodiments, the heat treatment holding time for carbonization is 2h to 6h, specifically 2h, 3h, 4h, 5h or 6h, etc., and of course other values ​​within the above range are also possible, which are not limited here.

[0134] In some embodiments, the carbonization process is carried out in a protective gas atmosphere, including at least one of nitrogen, helium, neon, argon, krypton, and xenon.

[0135] In some embodiments, the flow rate of the protective gas is 50 sccm to 500 sccm, specifically 50 sccm, 60 sccm, 70 sccm, 80 sccm, 90 sccm, 100 sccm, 200 sccm, 300 sccm, 400 sccm or 500 sccm, etc. Of course, it can also be other values ​​within the above range, which are not limited here.

[0136] In some embodiments, the process after carbonization and before pickling includes a step of pulverizing the carbonized material.

[0137] In some embodiments, the pulverization process includes at least one of grinding, mechanical pulverization, and air jet milling.

[0138] In some embodiments, the pulverization time is 5 min to 60 min, specifically 5 min, 10 min, 20 min, 30 min, 40 min, 50 min or 60 min, etc., and of course other values ​​within the above range are also possible, which are not limited here.

[0139] In some embodiments, the median particle size of the material obtained from the pulverization process is 5μm to 25μm, specifically 5μm, 10μm, 15μm, 20μm or 25μm, etc., and of course other values ​​within the above range are also possible, which are not limited here.

[0140] In some embodiments, the pickling process includes: performing a first water wash, an acid wash, and a second water wash on the carbonized material to remove spherical silica, rod-shaped zinc oxide, and ionic template agents from the carbonized material, thereby obtaining a carbon material containing spherical pores, cylindrical pores, and fissure pores. It can be understood that the carbonized material is first pulverized and then subjected to pickling.

[0141] In some embodiments, the solvents for the primary and secondary water washes include deionized water to remove residual acid from the material and ionic template agents.

[0142] In some implementations, the time for one wash is 2h to 6h, for example, it can be 2h, 3h, 4h, 5h or 6h, etc. Of course, it can also be other values ​​within the above range, which are not limited here.

[0143] In some implementations, the secondary washing time is 2h to 6h, for example, it can be 2h, 3h, 4h, 5h or 6h, or other values ​​within the above range, which are not limited here.

[0144] In some embodiments, the acid used for acid washing is at least one of hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, phosphoric acid, perchloric acid, acetic acid, and benzoic acid.

[0145] In some embodiments, the concentration of the acid washing solution is 0.1 mol / L to 2 mol / L, for example, it can be 0.1 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, or 2 mol / L, etc., and of course, other values ​​within the above range are also possible, without limitation. It is understood that the purpose of acid washing is to remove silicon oxide, zinc oxide, and alkaline ionic template agents from the material. The material obtained after carbonization treatment is acid-washed and then washed with deionized water until the product is nearly neutral.

[0146] In some embodiments, the acid washing time is 6h to 12h, for example, it can be 6h, 7h, 8h, 9h, 10h, 11h or 12h, etc. Of course, it can also be other values ​​within the above range, which are not limited here.

[0147] This application also provides a method for preparing a negative electrode material, using the above-mentioned carbon material as a raw material, specifically including the following steps: Anode materials are obtained by vapor deposition of carbon materials using gaseous active material precursors.

[0148] By performing vapor phase deposition on carbon materials, the precursor of the gaseous active material is transformed into an active material during the vapor phase deposition process. The active material is mainly deposited in the cylindrical pores of the carbon material, followed by the fissure pores, and the least amount is deposited in the spherical pores. This results in the prepared anode material meeting the following requirements: based on the pore volume of the anode material as 100%, the pore volume ratio of the cylindrical pores is less than 10%, the pore volume ratio of the spherical pores is 35%~95%, and the pore volume ratio of the fissure pores is 5%~65%.

[0149] In some embodiments, the gaseous active material precursor includes a gaseous silicon source, specifically, the gaseous silicon source includes at least one of silane, silane, dichlorosilane, and trichlorosilane.

[0150] In some embodiments, the flow rate of the gaseous active material precursor is 20 sccm to 100 sccm, specifically 20 sccm, 30 sccm, 40 sccm, 50 sccm, 60 sccm, 70 sccm, 80 sccm, 90 sccm, or 100 sccm, etc., and of course, other values ​​within the above range are also possible, which are not limited herein. Within the above-defined range, it is beneficial for the gaseous active material precursor and carbon material to mix thoroughly, thereby improving the deposition efficiency of the gaseous active material precursor.

[0151] In some embodiments, the temperature of vapor deposition is 500°C to 650°C, specifically 500°C, 530°C, 560°C, 600°C, 630°C and 650°C, etc., and of course other values ​​within the above range are also possible, which are not limited here.

[0152] In some embodiments, the heating rate of vapor deposition is 50℃ / h to 800℃ / h, specifically 50℃ / h, 100℃ / h, 200℃ / h, 300℃ / h, 400℃ / h, 500℃ / h, 600℃ / h, 700℃ / h or 800℃ / h, etc., and of course other values ​​within the above range are also possible, which are not limited herein.

[0153] In some embodiments, the vapor deposition time is 1h to 10h, specifically 1h, 3h, 5h, 7h, 9h and 10h, etc., and of course other values ​​within the above range are also possible, which are not limited here.

[0154] In some implementations, an auxiliary carrier gas is added during the vapor deposition process to remove oxygen from the vapor deposition equipment.

[0155] In some embodiments, the auxiliary carrier gas includes at least one of nitrogen, helium, and argon.

[0156] In some embodiments, the flow rate of the auxiliary carrier gas is 50 sccm to 200 sccm, specifically 50 sccm, 80 sccm, 100 sccm, 120 sccm, 150 sccm, 180 sccm or 200 sccm, etc., and of course, other values ​​within the above range are also possible, which are not limited here.

[0157] In some embodiments, the flow rate ratio of the gaseous active material precursor to the auxiliary carrier gas is (5~80):(50~200), specifically it can be 5:50, 10:70, 20:80, 30:100, 40:129, 50:150, 60:170, 70:180 or 80:120, etc. Of course, it can also be other values ​​within the above range, which are not limited here.

[0158] In some embodiments, the apparatus for vapor deposition includes at least one of a vapor-phase chemical deposition furnace and a fluidized bed.

[0159] In some embodiments, after performing vapor-phase deposition of carbon materials using vapor-phase active material precursors, the method further includes: mixing the vapor-deposited material and the coating material and then subjecting them to heat treatment.

[0160] In some embodiments, the coating material includes one of carbon materials, metal oxides, and nitrides.

[0161] In some embodiments, the nitride includes at least one of tin sulfide, molybdenum sulfide, titanium sulfide, iron sulfide, and copper sulfide.

[0162] In some embodiments, the metal oxide includes at least one of iron oxide, zinc oxide, tin oxide, copper oxide, and titanium oxide.

[0163] In some embodiments, the carbon source includes at least one of a gaseous carbon source and a solid carbon source.

[0164] In some embodiments, the gaseous carbon source includes at least one selected from acetylene, methane, propylene, benzene, ethanol, methanol, ethylene, propane, and butane.

[0165] In some embodiments, the flow rate of the gaseous carbon source is 0.1 L / min to 100 L / min, specifically 0.1 L / min, 1 L / min, 10 L / min, 30 L / min, 50 L / min, 80 L / min and 100 L / min, etc. Of course, it can also be other values ​​within the above range, which are not limited here.

[0166] In some embodiments, the solid carbon source includes at least one selected from sucrose, fructose, glucose, pitch, phenolic resin, polyimide, citric acid, epoxy resin, amino resin, polystyrene, polyacrylic acid, carboxymethyl cellulose, and cellulose acetate butyrate.

[0167] In some embodiments, the mass ratio of solid carbon source to carbon material is (1~100):100, specifically 1:100, 10:100, 30:100, 50:100, 80:100 and 100:100, etc. Of course, it can also be other values ​​within the above range, which are not limited here.

[0168] In some embodiments, the heat treatment temperature is 600℃~1100℃. Specifically, the heat treatment temperature can be, for example, 600℃, 650℃, 700℃, 800℃, 900℃, 1000℃, and 1000℃, etc., and of course, other values ​​within the above range are also possible, which are not limited herein. If the heat treatment temperature is below 600℃, the coating material will not be completely carbonized, and a dense coating layer cannot be obtained. If the heat treatment temperature is above 1100℃, the silicon material will crystallize, resulting in poor cycle performance and expansion performance of the negative electrode material.

[0169] In some embodiments, the heat treatment holding time is 2h to 10h. Specifically, the heat treatment holding time can be, for example, 2h, 5h, 7h, 8h and 10h, etc. Of course, it can also be other values ​​within the above range, which are not limited here.

[0170] Thirdly, this application provides a lithium-ion battery comprising the above-described negative electrode material or the negative electrode material prepared by the above-described preparation method.

[0171] Those skilled in the art will understand that the methods for preparing lithium-ion batteries described above are merely examples. Other methods commonly used in the art can be employed without departing from the disclosure of this application.

[0172] 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 can be made within the scope of the main claims. Example 1

[0173] (1) Add 8g of ion exchange resin and 7g of zinc acetate to 500mL of deionized water, stir evenly, add 4g of ammonia water, mix for 12h to form a uniform slurry, and then dry the slurry at 100℃ for 12h to form a precursor.

[0174] (2) In an atmosphere of 200 sccm argon gas flow, the precursor was carbonized at 900℃ for 4 h to form carbonized material. The carbonized material was then mechanically crushed for 30 min, followed by 2 h of water washing, 12 h of acid washing (1 mol / L hydrochloric acid), and 2 h of water washing to obtain carbon material.

[0175] (3) The carbon material was placed in a furnace, and 100 sccm of carrier argon gas was introduced for 1 hour. The temperature was then increased to 600°C at a rate of 100°C / hour. Then, 50 sccm of gaseous silicon source was introduced for 4 hours, during which time the temperature was kept constant and the furnace rotation speed was 5 r / min. After the deposition was completed, the silicon source was turned off, and the material was allowed to cool naturally to room temperature. The furnace was then turned off, and the negative electrode material was obtained.

[0176] The negative electrode material obtained in this embodiment includes carbon material and silicon active material. The carbon material has pores, and the silicon active material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the average pore diameter of the carbon material, the proportion of micropores in the carbon material, the specific surface area and the total pore volume of the carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the tap density, the specific surface area and the total pore volume are shown in Table 2. Example 2

[0177] (1) Add 8g of ion exchange resin, 7g of zinc acetate and 1g of tetraethoxysilane to 500mL of deionized water, stir evenly and then add 4g of ammonia water. Mix for 12h to form a uniform slurry, and then dry the slurry at 100℃ for 12h to form a precursor.

[0178] (2) In an atmosphere of 200 sccm argon gas flow, the precursor was carbonized at 900℃ for 4 h to form carbonized material. The carbonized material was then mechanically crushed for 30 min, followed by 2 h of water washing, 12 h of acid washing (hydrochloric acid), and 2 h of water washing to obtain carbon material.

[0179] (3) The carbon material was placed in a furnace, and 100 sccm of carrier argon gas was introduced for 1 hour. The temperature was then increased to 600°C at a rate of 100°C / hour. Then, 50 sccm of gaseous silicon source was introduced for 4 hours, during which time the temperature was kept constant and the furnace rotation speed was 5 r / min. After the deposition was completed, the silicon source was turned off, and the material was allowed to cool naturally to room temperature. The furnace was then turned off, and the negative electrode material was obtained.

[0180] The negative electrode material obtained in this embodiment includes carbon material and silicon active material. The carbon material has pores, and the silicon active material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the average pore diameter of the carbon material, the proportion of micropores in the carbon material, the specific surface area and the total pore volume of the carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the tap density, the specific surface area and the total pore volume are shown in Table 2. Example 3

[0181] (1) Add 8g of ion exchange resin, 5g of zinc acetate and 3g of tetraethoxysilane to 500mL of deionized water, stir evenly and then add 4g of ammonia water. Mix for 12h to form a uniform slurry, and then dry the slurry at 100℃ for 12h to form a precursor.

[0182] (2) In an atmosphere of 200 sccm argon gas flow, the precursor was carbonized at 900℃ for 4 h to form carbonized material. The carbonized material was then mechanically crushed for 30 min, followed by 2 h of water washing, 12 h of acid washing (hydrochloric acid), and 2 h of water washing to obtain carbon material.

[0183] (3) The carbon material was placed in a furnace, and 100 sccm of carrier argon gas was introduced for 1 hour. The temperature was then increased to 600°C at a rate of 100°C / hour. Then, 50 sccm of gaseous silicon source was introduced for 4 hours, during which time the temperature was kept constant and the furnace rotation speed was 5 r / min. After the deposition was completed, the silicon source was turned off, and the material was allowed to cool naturally to room temperature. The furnace was then turned off, and the negative electrode material was obtained.

[0184] The negative electrode material obtained in this embodiment includes carbon material and silicon active material. The carbon material has pores, and the silicon active material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the average pore diameter of the carbon material, the proportion of micropores in the carbon material, the specific surface area and the total pore volume of the carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the tap density, the specific surface area and the total pore volume are shown in Table 2. Example 4

[0185] (1) Add 8g of ion exchange resin, 3g of zinc acetate and 5g of tetraethoxysilane to 500mL of deionized water, stir evenly and then add 4g of ammonia water. Mix for 12h to form a uniform slurry, and then dry the slurry at 100℃ for 12h to form a precursor.

[0186] (2) In an atmosphere of 200 sccm argon gas flow, the precursor was carbonized at 900℃ for 4 h to form carbonized material. The carbonized material was then mechanically crushed for 30 min, followed by 2 h of water washing, 12 h of acid washing (hydrochloric acid), and 2 h of water washing to obtain carbon material.

[0187] (3) The carbon material was placed in a furnace, and 100 sccm of carrier argon gas was introduced for 1 hour. The temperature was then increased to 600°C at a rate of 100°C / hour. Then, 50 sccm of gaseous silicon source was introduced for 4 hours, during which time the temperature was kept constant and the furnace rotation speed was 5 r / min. After the deposition was completed, the silicon source was turned off, and the material was allowed to cool naturally to room temperature. The furnace was then turned off, and the negative electrode material was obtained.

[0188] The negative electrode material obtained in this embodiment includes carbon material and silicon active material. The carbon material has pores, and the silicon active material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the average pore diameter of the carbon material, the proportion of micropores in the carbon material, the specific surface area and the total pore volume of the carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the tap density, the specific surface area and the total pore volume are shown in Table 2. Example 5

[0189] (1) Add 8g of phenolic resin, 7g of zinc acetate and 1g of potassium hydroxide to 500mL of deionized water, stir evenly and then add 4g of ammonia water. Mix for 12h to form a uniform slurry, and then dry the slurry at 100℃ for 12h to form a precursor.

[0190] (2) In an atmosphere of 200 sccm argon gas flow, the precursor was carbonized at 900℃ for 4 h to form carbonized material. The carbonized material was then mechanically crushed for 30 min, followed by 2 h of water washing, 12 h of acid washing (hydrochloric acid), and 2 h of water washing to obtain carbon material.

[0191] (3) The carbon material was placed in a furnace, and 100 sccm of carrier argon gas was introduced for 1 hour. The temperature was then increased to 600°C at a rate of 100°C / hour. Then, 50 sccm of gaseous silicon source was introduced for 4 hours, during which time the temperature was kept constant and the furnace rotation speed was 5 r / min. After the deposition was completed, the silicon source was turned off, and the material was allowed to cool naturally to room temperature. The furnace was then turned off, and the negative electrode material was obtained.

[0192] The negative electrode material obtained in this embodiment includes carbon material and silicon active material. The carbon material has pores, and the silicon active material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the average pore diameter of the carbon material, the proportion of micropores in the carbon material, the specific surface area and the total pore volume of the carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the tap density, the specific surface area and the total pore volume are shown in Table 2. Example 6

[0193] (1) Add 8g of phenolic resin, 5g of zinc acetate and 3g of potassium hydroxide to 500mL of deionized water, stir evenly and then add 4g of ammonia water. Mix for 12h to form a uniform slurry, and then dry the slurry at 100℃ for 12h to form a precursor.

[0194] (2) In an atmosphere of 200 sccm argon gas flow, the precursor was carbonized at 900℃ for 4 h to form carbonized material. The carbonized material was then mechanically crushed for 30 min, followed by 2 h of water washing, 12 h of acid washing (hydrochloric acid), and 2 h of water washing to obtain carbon material.

[0195] (3) The carbon material was placed in a furnace, and 100 sccm of carrier argon gas was introduced for 1 hour. The temperature was then increased to 600°C at a rate of 100°C / hour. Then, 50 sccm of gaseous silicon source was introduced for 4 hours, during which time the temperature was kept constant and the furnace rotation speed was 5 r / min. After the deposition was completed, the silicon source was turned off, and the material was allowed to cool naturally to room temperature. The furnace was then turned off, and the negative electrode material was obtained.

[0196] The negative electrode material obtained in this embodiment includes carbon material and silicon active material. The carbon material has pores, and the silicon active material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the average pore diameter of the carbon material, the proportion of micropores in the carbon material, the specific surface area and the total pore volume of the carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the tap density, the specific surface area and the total pore volume are shown in Table 2. Example 7

[0197] (1) Add 8g of phenolic resin, 1g of zinc acetate and 7g of potassium hydroxide to 500mL of deionized water, stir evenly and then add 4g of ammonia water. Mix for 12h to form a uniform slurry, and then dry the slurry at 100℃ for 12h to form a precursor.

[0198] (2) In an atmosphere of 200 sccm argon gas flow, the precursor was carbonized at 900℃ for 4 h to form carbonized material. The carbonized material was then mechanically crushed for 30 min, followed by 2 h of water washing, 12 h of acid washing (hydrochloric acid), and 2 h of water washing to obtain carbon material.

[0199] (3) The carbon material was placed in a furnace, and 100 sccm of carrier argon gas was introduced for 1 hour. The temperature was then increased to 600°C at a rate of 100°C / hour. Then, 50 sccm of gaseous silicon source was introduced for 4 hours, during which time the temperature was kept constant and the furnace rotation speed was 5 r / min. After the deposition was completed, the silicon source was turned off, and the material was allowed to cool naturally to room temperature. The furnace was then turned off, and the negative electrode material was obtained.

[0200] The negative electrode material obtained in this embodiment includes carbon material and silicon active material. The carbon material has pores, and the silicon active material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the average pore diameter of the carbon material, the proportion of micropores in the carbon material, the specific surface area and the total pore volume of the carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the tap density, the specific surface area and the total pore volume are shown in Table 2. Example 8

[0201] (1) Add 8g of phenolic resin, 3g of zinc acetate, 1g of tetraethoxysilane and 3g of potassium hydroxide to 500mL of deionized water, stir evenly and then add 4g of ammonia water. Mix for 12h to form a uniform slurry, and then dry the slurry at 100℃ for 12h to form a precursor.

[0202] (2) In an atmosphere of 200 sccm argon gas flow, the precursor was carbonized at 900℃ for 4 h to form carbonized material. The carbonized material was then mechanically crushed for 30 min, followed by 2 h of water washing, 12 h of acid washing (hydrochloric acid), and 2 h of water washing to obtain carbon material.

[0203] (3) The carbon material was placed in a furnace, and 100 sccm of carrier argon gas was introduced for 1 hour. The temperature was then increased to 600°C at a rate of 100°C / hour. Then, 50 sccm of gaseous silicon source was introduced for 4 hours, during which time the temperature was kept constant and the furnace rotation speed was 5 r / min. After the deposition was completed, the silicon source was turned off, and the material was allowed to cool naturally to room temperature. The furnace was then turned off, and the negative electrode material was obtained.

[0204] The negative electrode material obtained in this embodiment includes carbon material and silicon active material. The carbon material has pores, and the silicon active material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the average pore diameter of the carbon material, the proportion of micropores in the carbon material, the specific surface area and the total pore volume of the carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the tap density, the specific surface area and the total pore volume are shown in Table 2. Example 9

[0205] (1) Add 8g of phenolic resin, 4g of zinc acetate, 2g of tetraethoxysilane and 2g of potassium hydroxide to 500mL of deionized water, stir evenly and then add 4g of ammonia water. Mix for 12h to form a uniform slurry, and then dry the slurry at 100℃ for 12h to form a precursor.

[0206] (2) In an atmosphere of 200 sccm argon gas flow, the precursor was carbonized at 900℃ for 4 h to form carbonized material. The carbonized material was then mechanically crushed for 30 min, followed by 2 h of water washing, 12 h of acid washing (hydrochloric acid), and 2 h of water washing to obtain carbon material.

[0207] (3) The carbon material was placed in a furnace, and 100 sccm of carrier argon gas was introduced for 1 hour. The temperature was then increased to 600°C at a rate of 100°C / hour. Then, 50 sccm of gaseous silicon source was introduced for 4 hours, during which time the temperature was kept constant and the furnace rotation speed was 5 r / min. After the deposition was completed, the silicon source was turned off, and the material was allowed to cool naturally to room temperature. The furnace was then turned off, and the negative electrode material was obtained.

[0208] The negative electrode material obtained in this embodiment includes carbon material and silicon active material. The carbon material has pores, and the silicon active material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the average pore diameter of the carbon material, the proportion of micropores in the carbon material, the specific surface area and the total pore volume of the carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the tap density, the specific surface area and the total pore volume are shown in Table 2. Example 10

[0209] (1) Add 8g of phenolic resin, 4g of zinc acetate, 3g of tetraethoxysilane and 1g of potassium hydroxide to 500mL of deionized water, stir evenly and then add 4g of ammonia water. Mix for 12h to form a uniform slurry, and then dry the slurry at 100℃ for 12h to form a precursor.

[0210] (2) In an atmosphere of 200 sccm argon gas flow, the precursor was carbonized at 900℃ for 4 h to form carbonized material. The carbonized material was then mechanically crushed for 30 min, followed by 2 h of water washing, 12 h of acid washing (hydrochloric acid), and 2 h of water washing to obtain carbon material.

[0211] (3) The carbon material was placed in a furnace, and 100 sccm of carrier argon gas was introduced for 1 hour. The temperature was then increased to 600°C at a rate of 100°C / hour. Then, 50 sccm of gaseous silicon source was introduced for 4 hours, during which time the temperature was kept constant and the furnace rotation speed was 5 r / min. After the deposition was completed, the silicon source was turned off, and the material was allowed to cool naturally to room temperature. The furnace was then turned off, and the negative electrode material was obtained.

[0212] The negative electrode material obtained in this embodiment includes carbon material and silicon active material. The carbon material has pores, and the silicon active material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the average pore diameter of the carbon material, the proportion of micropores in the carbon material, the specific surface area and the total pore volume of the carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the tap density, the specific surface area and the total pore volume are shown in Table 2.

[0213] Figure 5 This is a pore size distribution diagram of the cylindrical pores, fissure pores, and spherical pores in the carbon material prepared in this embodiment. Figure 5 (a) in the diagram shows the pore size distribution of the fractured pores. Figure 5 (b) in the diagram shows the pore size distribution of the cylindrical pores. Figure 5 (c) in the diagram shows the aperture distribution of the spherical aperture; Figure 6 This is a pore size distribution diagram of the cylindrical pores, slit pores, and spherical pores of the negative electrode material prepared in this embodiment. Figure 6 (a) in the diagram shows the pore size distribution of the fractured pores. Figure 6 (b) in the diagram shows the pore size distribution of the cylindrical pores. Figure 6 (c) in the diagram shows the aperture distribution of the spherical aperture. Figure 7 This is a cumulative pore volume distribution diagram of the carbon material prepared in this embodiment. Figure 8 This is a cumulative pore volume distribution diagram of the negative electrode material prepared in this embodiment, based on... Figures 5-8It can be seen that in carbon materials, the pore volume ratio of fissure pores is 38%, that of cylindrical pores is 52%, and that of spherical pores is 10%. In the anode material after filling with active material, the pore volume ratio of fissure pores is 30%, that of cylindrical pores is 0%, and that of spherical pores is 70%. This indicates that by adjusting the pore volume ratios of fissure pores, cylindrical pores, and spherical pores in carbon materials, after the active material is filled into the carbon materials, the cylindrical pores are basically filled, and the fissure pores and spherical pores are also partially filled. This greatly improves the utilization rate of the pores in the anode material, which is beneficial for obtaining anode materials with excellent capacity and first-efficiency. Example 11

[0214] (1) Add 8g of phenolic resin, 5g of zinc acetate, 1g of tetraethoxysilane and 2g of potassium hydroxide to 500mL of deionized water, stir evenly and then add 4g of ammonia water. Mix for 12h to form a uniform slurry, and then dry the slurry at 100℃ for 12h to form a precursor.

[0215] (2) In an atmosphere of 200 sccm argon gas flow, the precursor was carbonized at 900℃ for 4 h to form carbonized material. The carbonized material was then mechanically crushed for 30 min, followed by 2 h of water washing, 12 h of acid washing (hydrochloric acid), and 2 h of water washing to obtain carbon material.

[0216] (3) The carbon material was placed in a furnace, and 100 sccm of carrier argon gas was introduced for 1 hour. The temperature was then increased to 600°C at a rate of 100°C / hour. Then, 50 sccm of gaseous silicon source was introduced for 4 hours, during which time the temperature was kept constant and the furnace rotation speed was 5 r / min. After the deposition was completed, the silicon source was turned off, and the material was allowed to cool naturally to room temperature. The furnace was then turned off, and the negative electrode material was obtained.

[0217] The negative electrode material obtained in this embodiment includes carbon material and silicon active material. The carbon material has pores, and the silicon active material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the average pore diameter of the carbon material, the proportion of micropores in the carbon material, the specific surface area and the total pore volume of the carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the tap density, the specific surface area and the total pore volume are shown in Table 2. Example 12

[0218] (1) Add 8g of phenolic resin, 6g of zinc acetate, 1g of tetraethoxysilane and 1g of potassium hydroxide to 500mL of deionized water, stir evenly and then add 4g of ammonia water. Mix for 12h to form a uniform slurry, and then dry the slurry at 100℃ for 12h to form a precursor.

[0219] (2) In an atmosphere of 200 sccm argon gas flow, the precursor was carbonized at 900℃ for 4 h to form carbonized material. The carbonized material was then mechanically crushed for 30 min, followed by 2 h of water washing, 12 h of acid washing (hydrochloric acid), and 2 h of water washing to obtain carbon material.

[0220] (3) The carbon material was placed in a furnace, and 100 sccm of carrier argon gas was introduced for 1 hour. The temperature was then increased to 600°C at a rate of 100°C / hour. Then, 50 sccm of gaseous silicon source was introduced for 4 hours, during which time the temperature was kept constant and the furnace rotation speed was 5 r / min. After the deposition was completed, the silicon source was turned off, and the material was allowed to cool naturally to room temperature. The furnace was then turned off, and the negative electrode material was obtained.

[0221] The negative electrode material obtained in this embodiment includes carbon material and active material. The carbon material has pores, and silicon material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, fissure pores, cylindrical pores, average pore diameter of carbon material pores, number ratio of micropores in carbon material, specific surface area and total pore volume of carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, fissure pores, cylindrical pores, tap density, specific surface area and total pore volume are shown in Table 2. Example 13

[0222] (1) Add 8g of phenolic resin, 6g of zinc acetate, 0.5g of tetraethoxysilane and 1.5g of potassium hydroxide to 500mL of deionized water, stir evenly and then add 4g of ammonia water. Mix for 12h to form a uniform slurry, and then dry the slurry at 100℃ for 12h to form a precursor.

[0223] (2) In an atmosphere of 200 sccm argon gas flow, the precursor was carbonized at 900℃ for 4 h to form carbonized material. The carbonized material was then mechanically crushed for 30 min, followed by 2 h of water washing, 12 h of acid washing (hydrochloric acid), and 2 h of water washing to obtain carbon material.

[0224] (3) The carbon material was placed in a furnace, and 100 sccm of carrier argon gas was introduced for 1 hour. The temperature was then increased to 600°C at a rate of 100°C / hour. Then, 50 sccm of gaseous silicon source was introduced for 4 hours, during which time the temperature was kept constant and the furnace rotation speed was 5 r / min. After the deposition was completed, the silicon source was turned off, and the material was allowed to cool naturally to room temperature. The furnace was then turned off, and the negative electrode material was obtained.

[0225] The negative electrode material obtained in this embodiment includes carbon material and silicon active material. The carbon material has pores, and the silicon active material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the average pore diameter of the carbon material, the proportion of micropores in the carbon material, the specific surface area and the total pore volume of the carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the tap density, the specific surface area and the total pore volume are shown in Table 2. Comparative Example 1

[0226] The difference from Example 1 is that in step (1): 8g of ion exchange resin and 8g of zinc acetate are added to 500mL of deionized water, stirred evenly, and then 4g of ammonia water is added. The mixture is mixed for 12h to form a uniform slurry, and then the slurry is dried at 100℃ for 12h to form a precursor.

[0227] The negative electrode material obtained in this comparative example includes carbon material and active material. The carbon material has pores, and silicon material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the average pore diameter of the carbon material, the proportion of the number of micropores in the carbon material, the specific surface area and the total pore volume of the carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the tap density, the specific surface area and the total pore volume are shown in Table 2. Comparative Example 2

[0228] The difference from Example 1 is that in step (1): 8g of ion exchange resin and 5g of tetraethoxysilane are added to 500mL of deionized water, stirred evenly, and then 4g of ammonia water is added. The mixture is mixed for 12h to form a uniform slurry, and then the slurry is dried at 100℃ for 12h to form a precursor.

[0229] The negative electrode material obtained in this comparative example includes carbon material and active material. The carbon material has pores, and silicon material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the average pore diameter of the carbon material, the proportion of the number of micropores in the carbon material, the specific surface area and the total pore volume of the carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the tap density, the specific surface area and the total pore volume are shown in Table 2. Comparative Example 3

[0230] The difference from Example 1 is that in step (1): 8g of ion exchange resin and 5g of potassium hydroxide are added to 500mL of deionized water, stirred evenly, and then 4g of ammonia water is added. The mixture is mixed for 12h to form a uniform slurry, and then the slurry is dried at 100℃ for 12h to form a precursor.

[0231] The negative electrode material obtained in this comparative example includes carbon material and active material. The carbon material has pores, and silicon material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the average pore diameter of the carbon material, the proportion of the number of micropores in the carbon material, the specific surface area and the total pore volume of the carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the tap density, the specific surface area and the total pore volume are shown in Table 2. Comparative Example 4

[0232] The difference from Example 1 is that in step (1): 8g of ion exchange resin, 10g of zinc acetate and 4g of tetraethoxysilane are added to 500mL of deionized water, stirred evenly and then 4g of ammonia water is added. The mixture is mixed for 12h to form a uniform slurry, and then the slurry is dried at 100℃ for 12h to form a precursor.

[0233] The negative electrode material obtained in this comparative example includes carbon material and active material. The carbon material has pores, and silicon material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the average pore diameter of the carbon material, the proportion of the number of micropores in the carbon material, the specific surface area and the total pore volume of the carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the tap density, the specific surface area and the total pore volume are shown in Table 2. Comparative Example 5

[0234] The difference from Example 1 is that in step (1): 8g of phenolic resin, 0.5g of zinc acetate, 10g of potassium hydroxide and 4g of tetraethoxysilane are added to 500mL of deionized water, stirred evenly and then 4g of ammonia water is added. The mixture is mixed for 12h to form a uniform slurry, and then the slurry is dried at 100℃ for 12h to form a precursor.

[0235] The negative electrode material obtained in this comparative example includes carbon material and active material. The carbon material has pores, and silicon material is at least partially distributed in the pores. The morphology of the pores includes cylindrical pores, fissure pores, and spherical pores. Taking the pore volume of the carbon material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the average pore diameter of the carbon material, the proportion of the number of micropores in the carbon material, the specific surface area and the total pore volume of the carbon material are shown in Table 1. Taking the pore volume of the negative electrode material as 100%, the pore volume ratio of spherical pores, the pore volume ratio of fissure pores, the pore volume ratio of cylindrical pores, the tap density, the specific surface area and the total pore volume are shown in Table 2.

[0236] Performance testing

[0237] 1. The pore volume of carbon materials and anode materials was tested using the Phytolink iPore620 pore size analyzer and the BET pore size distribution method. It's understood that before testing the pore volume of different pores in the carbon material, the silicon material in the anode material needs to be etched away using HF. Specifically: The nitrogen isothermal adsorption and desorption characteristic curves of carbon materials and anode materials were obtained using the Phytolink iPore620 pore size analyzer and the BET pore size distribution method. The nitrogen isothermal adsorption and desorption curve data of carbon materials and anode materials were then imported into Phytolink iPore DFT software for pore type simulation calculations. In the simulation, ExperimentIsotherm is set to P / P0, CDFT Model is set to Mixing Model, and the three simulation analysis items "N2 in Carbon Slit pore at 77K", "N2 in Carbon Cylindrical pore at 77K" and "N2 in Carbon Spherical pore at 77K" are checked. Min Pressure (atm) is set to 0, Max Pressure (atm) is set to 0.9, and Smooth Factor is set to 4. Finally, click OK to obtain the total pore volume of carbon material and anode material, as well as the pore volume ratios of slit pores, cylindrical pores, and spherical pores through DFT simulation analysis. In the DFT simulation, the slit pore is simulated as a slit composed of two semi-infinite, parallel graphite plates; the cylindrical pore is simulated as a cylindrical pore type, such as the CMK-3 porous carbon pore type synthesized based on the SBA-15 porous silicon hard template; and the spherical pore is simulated as a large cage-like pore connected by smaller pores.

[0238] 2. The number of micropores in carbon materials was determined by nitrogen desorption.

[0239] 3. Before etching the silicon material in the negative electrode material, test the mass M1 of the negative electrode material. After etching the silicon material with HF, test the mass M2 of the negative electrode material. (M1-M2) / M1 is the mass ratio of silicon material in the negative electrode material.

[0240] 4. The median particle size of the negative electrode material was measured using a laser particle size analyzer.

[0241] 5. After etching the silicon material in the carbon material using HF, the average pore diameter was tested using a Micromeritics ASAP 2460 fully automated surface area and porosity analyzer. The gas used for the test was CO2 or N2.

[0242] 6. Test method for median particle size of silicon materials: Perform mathematical statistics on the diameter of silicon materials in transmission electron microscopy images.

[0243] 7. Etching Test The negative electrode material was soaked in 68% concentrated nitric acid for 1 hour. Then, 20% HF acid solution was added dropwise to the negative electrode material, which produced yellow fumes. This process was repeated until no more yellow fumes were produced in the solution. Finally, the residue was digested with 68% concentrated nitric acid, and then the material was washed and dried to obtain the negative electrode material after removing silicon particles.

[0244] 8. The following methods were used to test the electrochemical performance of the negative electrode material: The negative electrode material, conductive agent, and binder were dissolved in a solvent at a mass ratio of 94:1:5, with the solid content controlled at 50%. This mixture was then coated onto a copper foil current collector and vacuum dried to obtain the negative electrode sheet. Next, a ternary positive electrode sheet prepared using conventional mature processes, a 1 mol / L LiPF6 / EC+DMC+EMC (v / v=1:1:1) electrolyte, a Celgard 2400 separator, and a casing were assembled into an 18650 cylindrical cell using conventional manufacturing processes. The charge and discharge tests of the cylindrical cells were conducted on the LAND battery testing system of Wuhan Jinno Electronics Co., Ltd., testing their charging capacity and initial efficiency. Examples 1-13 are designated S1-S13, and Comparative Examples 1-5 are designated D1-D5. The test results are shown in Tables 1-2.

[0245] Table 1. Carbon material tests in each embodiment and comparative example S1 5 80 15 3.2 0.3462 924 S2 7 78 15 4.3 0.7763 1632 S3 8 48 44 6.2 0.7549 1363 S4 7 42 51 7.3 0.6282 929 S5 15 79 6 3.4 0.8349 1720 S6 47 46 7 2.1 0.8674 1883 S7 54 41 5 1.7 0.9789 1982 S8 38 52 10 1.8 0.9459 1930 S9 27 54 19 1.9 0.8649 1890 S10 16 53 31 2.8 0.8372 1803 S11 25 59 16 3.2 0.7754 1773 S12 17 71 12 3.7 0.8392 1642 S13 20 72 8 3.5 0.8563 1723 D1 12 85 3 3.2 0.7533 1752 D2 15 7 78 12.6 0.7642 850 D3 93 5 2 1.6 0.5517 723 D4 1 18 81 7.9 0.9241 1754 D5 76 13 11 8.1 1.1304 1859 Table 2. Test results of negative electrode materials in each embodiment and comparative example. S1 28 3 69 0.0053 4.2 4.6 0.88 1342 93.2 S2 27 9 65 0.0307 8.5 35 0.89 1999 91.7 S3 25 1 74 0.0505 9.2 62 0.87 1982 91.0 S4 13 2 81 0.0912 11.1 93 0.84 1905 89.2 S5 44 7 49 0.0232 7.5 31 0.92 2026 92.5 S6 48 1 51 0.0142 4.3 20 0.98 2089 91.6 S7 64 1 35 0.0353 3.7 42 0.88 1994 92.4 S8 30 0 70 0.0171 4.5 22 0.96 2083 93.5 S9 12 0 88 0.0052 5.7 2.5 1.12 2180 93.1 S10 8 0 92 0.0094 7.4 3.4 1.07 2142 93.7 S11 17 0 83 0.0048 7.2 1.6 1.16 2193 93.0 S12 28 5 72 0.0103 6.3 3.5 1.03 2113 92.5 S13 28 6 66 0.0112 6.2 16 1.01 2095 92.5 D1 27 12 61 0.1433 3.9 45 0.89 1820 86 D2 4 0 96 0.3502 17.2 593 0.54 1433 76 D3 72 0 28 0.2437 6.5 487 0.63 843 81 D4 5 0 95 0.4783 15.3 732 0.51 1549 59 D5 68 7 25 0.6302 14.2 1245 0.47 1524 53 As shown in Tables 1 and 2, the negative electrode materials prepared in Examples 1-13 of this application exhibit the following porosity: cylindrical pores have the highest porosity utilization for filling the active material, followed by fissure pores, while spherical pores have the lowest porosity utilization. This means that the active material is mainly filled in the cylindrical pores, followed by the fissure pores, and the spherical pores have the least filling. This is beneficial for increasing the amount of active material filling the negative electrode material, thereby improving the capacity and initial efficiency of the negative electrode material. Furthermore, the active material has a relatively definite deposition location within the carbon material, further improving the expansion performance, capacity, and initial efficiency of the negative electrode material.

[0246] In Comparative Example 1, only zinc acetate was used as a pore-forming agent, and the amount of zinc acetate added was too large. The carbon material prepared was mainly composed of cylindrical pores, with too few spherical pores. The carbon material had a single pore type and the pore connections were not well developed. When active materials were deposited in the carbon material, it was easy to cause pore blockage, reduce the pore utilization rate of the material, and the pore volume of the negative electrode material was large, which led to the degradation of the capacity and initial efficiency of the negative electrode material.

[0247] In Comparative Example 2, only tetraethoxysilane pore-forming agent was used. The carbon material prepared was mainly composed of spherical pores, with a low proportion of slit pores and cylindrical pores. In the prepared negative electrode material, the active material was mainly deposited in the spherical pores. Due to the narrow neck width of the spherical pores, the amount of active material deposited was low, and the active material was prone to accumulate in the neck of the spherical pores, causing pore blockage and reducing the utilization rate of the pores of the negative electrode material. This resulted in a decrease in the capacity and initial efficiency of the negative electrode material.

[0248] In Comparative Example 3, only potassium hydroxide was used as a pore-forming agent. The carbon material prepared was mainly composed of fissure pores, with a low proportion of spherical and cylindrical pores. In the prepared negative electrode material, the active material was mainly deposited in the fissure pores. Since the pore width of fissure pores is usually 2-3 times the graphite interlayer spacing (0.34 nm), while the diameter of active material such as silane molecules is 0.355 nm, a large number of fissure pores cannot be filled by silane molecules, reducing the pore utilization rate of the negative electrode material and resulting in a decrease in the capacity and initial efficiency of the negative electrode material.

[0249] Comparative Example 4 added three pore-forming agents, and the amount of zinc acetate added was too large. During the preparation of carbon materials, zinc oxide agglomerates formed by zinc acetate were formed, and the rod-shaped structure was reduced. This resulted in a significant decrease in the proportion of cylindrical pores and an increase in the proportion of spherical pores in the carbon materials. Consequently, the deposition efficiency of silicon in the subsequent vapor deposition process decreased, and the capacity of the anode material decreased. At the same time, the anode material still maintained a large pore volume. The large pore volume reduced the compaction density and initial efficiency of the anode material.

[0250] Comparative Example 5 added three pore-forming agents, and the amount of potassium hydroxide added was too large. The carbon material prepared was mainly composed of crack pores, and the proportion of cylindrical pores was too small, which led to a significant decrease in silicon deposition efficiency and a reduction in the porosity utilization of the anode material. Consequently, the compaction density, capacity and first-time efficiency of the anode material were significantly reduced.

[0251] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A negative electrode material, characterized in that, The negative electrode material includes carbon material and active material. The carbon material includes hard carbon, and the active material includes at least one of Sn, Ge, and Si. The carbon material has pores, including cylindrical pores, spherical pores, and slit pores. The active material is at least partially distributed within the pores. Based on the pore volume of the carbon material being 100%, the pore volume ratio of the cylindrical pores is 40%~78%, the pore volume ratio of the spherical pores is 10%~55%, and the pore volume ratio of the slit pores is 5%~40%. With the pore volume of the negative electrode material being 100%, the pore volume ratio of the cylindrical pores in the negative electrode material is less than 10%, the pore volume ratio of the spherical pores in the negative electrode material is 65%~95%, and the pore volume ratio of the fissure pores in the negative electrode material is 5%~30%. The average pore size of the carbon material is 1.7~7.3 nm, and the total pore volume of the carbon material is 0.3 cm³. 3 / g~1.0cm 3 / g, the specific surface area of ​​the carbon material is 900m². 2 / g~2000m 2 / g.

2. The negative electrode material according to claim 1, characterized in that, The median particle size of the carbon material is 5 μm to 25 μm.

3. The negative electrode material according to claim 1, characterized in that, With the pore volume of the negative electrode material after removing the active material as 100%, the pore volume ratio of the cylindrical pores is 40%~80%, the pore volume ratio of the spherical pores is 5%~55%, and the pore volume ratio of the slit pores is 5%~55%.

4. The negative electrode material according to claim 1, characterized in that, The active material includes silicon-based materials, and the median particle size of the silicon-based materials is 1 nm to 10 nm.

5. The negative electrode material according to claim 1, characterized in that, The negative electrode material also includes a coating layer distributed on at least a portion of the surface of the carbon material.

6. The negative electrode material according to claim 1, characterized in that, The negative electrode material further includes a coating layer distributed on at least a portion of the surface of the carbon material, the coating layer comprising a carbon layer, the carbon layer being made of at least one of graphene, soft carbon, hard carbon, and conductive polymer.

7. The negative electrode material according to claim 1, characterized in that, The negative electrode material further includes a coating layer distributed on at least a portion of the surface of the carbon material, the coating layer comprising a metal oxide layer, the metal oxide layer being made of at least one of titanium oxide, aluminum oxide, lithium oxide, cobalt oxide, and vanadium oxide.

8. The negative electrode material according to claim 1, characterized in that, The negative electrode material further includes a coating layer distributed on at least a portion of the surface of the carbon material, the coating layer including a nitride layer, the material of which includes at least one of titanium nitride, vanadium nitride, cobalt nitride, nickel nitride, and carbon nitride.

9. The negative electrode material according to claim 1, characterized in that, The negative electrode material further includes a coating layer distributed on at least a portion of the surface of the carbon material, the thickness of which is 0.1 nm to 100 nm.

10. The negative electrode material according to claim 1, characterized in that, The median particle size of the negative electrode material is 5 μm to 30 μm.

11. The negative electrode material according to claim 1, characterized in that, The average pore size of the pores in the negative electrode material is 3.7 nm to 11.1 nm.

12. The negative electrode material according to claim 1, characterized in that, The specific surface area of ​​the negative electrode material is 1m². 2 / g ~100m 2 / g.

13. The negative electrode material according to claim 1, characterized in that, The total pore volume of the negative electrode material is 0.005 cm³. 3 / g~0.1 cm 3 / g.

14. The negative electrode material according to claim 1, characterized in that, The compaction density of the negative electrode material is 0.8 g / cm³. 3 ~1.2 g / cm 3 .

15. A lithium-ion battery, characterized in that, The lithium-ion battery includes the negative electrode material as described in any one of claims 1 to 14.

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