Negative electrode material and manufacturing method thereof, lithium ion battery

Abstract

The present application relates to a negative electrode material, a manufacturing method thereof, and a lithium ion battery. The negative electrode material includes a silicon-based core and a coating layer located on at least a portion of the surface of the silicon-based core, the silicon-based core including a silicon oxide and a lithium silicate, and the coating layer including a carbon material. 20 mg of the negative electrode material is added to 10 ml of deionized water to form a slurry, and the zeta potential of the slurry is measured using a nanoparticle size and zeta potential analyzer. In the zeta potential distribution diagram of the slurry, the intensity of a first characteristic peak within a zeta potential range of -50 mV to -40 mV of the slurry is defined as I1, the intensity of a second characteristic peak within a zeta potential range of -65 mV to -50 mV is defined as I2, and the intensity of a third characteristic peak within a zeta potential range of -35 mV to -25 mV is defined as I3. I1, I2, and I3 satisfy the relationships 0≦I2 / I1≦2.0 and 0≦I3 / I1≦1.0. The technical solution of the present application can reduce the volume expansion of the negative electrode material and improve the rate performance and cycle performance of the negative electrode material.

Description

[Technical Field]

[0001] This application claims priority from a Chinese patent application filed with the China Patent Office on September 27, 2023, bearing application number 2023112774159 and entitled "Negative electrode material and manufacturing method thereof, for lithium ion batteries," the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the technical field of negative electrode materials, and in particular to a negative electrode material and a method for producing the same, and to lithium ion batteries. [Background technology]

[0003] Lithium-ion batteries have advantages such as high energy density, long cycle life, minimal environmental pollution, and no memory effect, making them widely used in electric vehicles and consumer electronic products. Anode materials are an important component of lithium-ion batteries and directly affect key indicators such as battery energy density, cycle life, and safety performance. As the range requirements for practical applications of new energy vehicles continue to increase, power battery-related materials are also developing to achieve higher energy densities. Traditional lithium-ion battery graphite anodes are no longer able to meet current requirements, making high-energy-density anode materials a new hotspot for companies to pursue.

[0004] Silicon-based anode materials are one of the most important materials for high-energy-density lithium-ion batteries, but traditional silicon-based anode materials suffer from issues such as large volume expansion and poor rate performance, which affect their widespread application in lithium-ion batteries. Currently, coating silicon-based anode materials with a single carbon material is the standard coating option. Although carbon materials can improve the material's electrical conductivity, traditional carbon coating techniques still have many shortcomings.

[0005] Therefore, the development of anode materials with excellent cycle performance and low volume expansion effect, as well as the manufacturing method thereof, remains a technical challenge in the field. Summary of the Invention [Problem to be solved by the invention]

[0006] The embodiments of the present application provide a negative electrode material and a manufacturing method thereof for reducing the volume expansion of the negative electrode material and improving the rate performance and cycle performance of the negative electrode material, and a lithium ion battery. [Means for solving the problem]

[0007] In a first aspect, embodiments of the present application provide the following negative electrode material: The negative electrode material includes a silicon-based core and a coating layer located on at least a portion of the silicon-based core, the silicon-based core including a silicate and a lithium silicate, and the coating layer including a carbon material; 20 mg of the negative electrode material was added to 10 ml of deionized water to form a slurry, and the zeta potential of the slurry was measured using a nanoparticle size and zeta potential analyzer. In the zeta potential measurement distribution diagram of the slurry, the maximum intensity of the first characteristic peak within the zeta potential range of -50 mV to -40 mV of the slurry is defined as I1, the maximum intensity of the second characteristic peak within the zeta potential range of -65 mV to -50 mV is defined as I2, and the maximum intensity of the third characteristic peak within the zeta potential range of -35 mV to -25 mV is defined as I3. I1, I2, and I3 satisfy the relationships 0≦I2 / I1≦2.0 and 0≦I3 / I1≦1.0.

[0008] In a second aspect, embodiments of the present application provide a method for producing a negative electrode material, the method comprising the steps of: A coating agent and a coating gas source containing a gaseous carbon source are used in combination to form a coating layer on the surface of a silicon-based core by vapor deposition to obtain a negative electrode material, wherein the coating agent is a non-vapor-phase coating agent having a benzene ring structure, and the silicon-based core contains silicon oxide and lithium silicate.

[0009] In a third aspect, the present application provides a lithium ion battery comprising the negative electrode material according to the first aspect or the negative electrode material produced by the method for producing the negative electrode material according to the second aspect. [Effects of the Invention]

[0010] Compared with the prior art, the technical solution of the present application has at least the following beneficial effects:

[0011] The negative electrode material according to the present invention comprises a silicon-based core and a coating layer located on the surface of the silicon-based core, the coating layer comprising a carbon material, which effectively blocks the silicon-based core from being exposed to an electrolyte, reduces the loss of active silicon and active lithium in the silicon-based core, and improves the cycle performance of the negative electrode material, the silicon-based core comprising silicon oxide and lithium silicate; after forming the negative electrode material into a slurry, a nanoparticle size and zeta potential analyzer is used to measure the zeta potential of the slurry, and in the zeta potential measurement distribution diagram of the slurry, I1, I2, and I3 are These terms refer to the forms and contents of the three materials—carbon material, lithium silicate, and silicon oxide—on the surface of the negative electrode material. That is, the surface of the negative electrode material may contain a combination of materials such as lithium silicate, carbon material, and silicon oxide. When I1, I2, and I3 satisfy the relationships 0≦I2 / I1≦2.0 and 0≦I3 / I1≦1.0, the interfacial reaction between the negative electrode material and the electrolyte is good, a high-speed mass and charge transfer interface is established between the negative electrode material and the electrolyte, improving the material charge conduction efficiency and the rate performance of the negative electrode material. Controlling the solid-liquid reaction between the surface of the negative electrode material and the electrolyte can form a stable SEI interface on the surface of the negative electrode material, reducing electrolyte decomposition and suppressing cycle swelling of the negative electrode pieces, thereby improving the cycle performance of the negative electrode material.

[0012] The method for producing a negative electrode material according to the present application involves producing the negative electrode material by vapor-depositing a silicon-based core using a gas-phase carbon source, and then adding a solid-phase coating agent and / or a liquid-phase coating agent to carry out vapor-phase deposition. During the vapor-phase deposition process, different carbon sources have different dissociation efficiencies at the same temperature, and also different deposition efficiencies on the surface of the silicon-based core. As a result, different types of carbon sources are sequentially deposited on the surface of the silicon-based core, forming differentiated deposition on the surface of the silicon-based core. The carbon material formed by dissociation of the gas-phase carbon source is deposited on the surface of the silicon-based core to form a coating layer, and the carbon material formed by dissociation of the solid-phase coating agent and / or liquid-phase coating agent is deposited on the coating layer and is embedded in the coating layer. Because the solid-phase coating agent and / or liquid-phase coating agent have a benzene ring structure, this benzene ring structure is mainly derived from aromatic organic substances with low melting and boiling points. These organic substances can further perform surface modification and functional doping on the coating layer during the carbonization process, thereby optimizing the surface of the coating layer of the anode material, adjusting and controlling the surface of the anode material, and further controlling the solid-liquid interfacial reaction between the anode material and the electrolyte, thereby improving the processing performance and cycle performance of the anode material. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a process flow diagram of a method for producing a negative electrode material according to an embodiment of the present application. [Figure 2] FIG. 2 is a zeta potential measurement distribution diagram of the negative electrode material according to Example 1 of the present application. [Figure 3] FIG. 10 is a zeta potential measurement distribution diagram of a negative electrode material according to Example 2 of the present application. [Figure 4] FIG. 10 is a zeta potential measurement distribution diagram of a negative electrode material according to Example 3 of the present application. [Figure 5] FIG. 10 is a zeta potential measurement distribution diagram of a negative electrode material according to Example 4 of the present application. [Figure 6] FIG. 10 is a zeta potential measurement distribution diagram of a negative electrode material according to Example 5 of the present application. [Figure 7] FIG. 1 is a zeta potential measurement distribution diagram of a negative electrode material according to Comparative Example 1 of the present application. [Figure 8]FIG. 10 is a zeta potential measurement distribution diagram of a negative electrode material according to Comparative Example 2 of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0014] In order to better understand the technical solution of the present application, the following detailed description of the embodiments of the present invention will be given with reference to the accompanying drawings.

[0015] It should be clear that the embodiments described in this specification are only some of the embodiments of the present application, and are not all of the embodiments of the present application. Based on the embodiments of the present application, all other embodiments that can be made by a person skilled in the art without any creative effort fall within the scope of protection of the present application.

[0016] The terms used in the examples of this application are used only to describe specific examples and are not intended to limit the present invention. As used in the examples and claims of this application, the singular forms "a," "one," "the," "said," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0017] It should be understood that the term "and / or" used herein is only a relational relationship that describes related objects, and indicates that three types of relationships may exist. For example, A and / or B can indicate three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the symbol " / " in this specification generally indicates that the related objects before and after it are in an "or" relationship.

[0018] In a first aspect, embodiments of the present application provide an anode material, the anode material including a silicon-based core and a coating layer located on at least a portion of the silicon-based core, the silicon-based core including a silicate and a lithium silicate, and the coating layer including a carbon material; 20 mg of negative electrode material was added to 10 ml of deionized water to form a slurry, and the zeta potential of the slurry was measured using a nanoparticle size and zeta potential analyzer. In the zeta potential measurement distribution diagram of the negative electrode slurry, the maximum intensity of the first characteristic peak within the zeta potential range of the slurry from -50 mV to -40 mV was defined as I1, the maximum intensity of the second characteristic peak within the zeta potential range from -65 mV to -50 mV was defined as I2, and the maximum intensity of the third characteristic peak within the zeta potential range from -35 mV to -25 mV was defined as I3, where I1, I2, and I3 satisfy the relationships 0≦I2 / I1≦2.0 and 0≦I3 / I1≦1.0.

[0019] The negative electrode material according to the present invention comprises a silicon-based core and a coating layer located on the surface of the silicon-based core, the coating layer being made of a carbon material, and the coating layer effectively blocks the silicon-based core from being exposed to an electrolyte, reducing the loss of active silicon and active lithium in the silicon-based core and improving the cycle performance of the negative electrode material, the silicon-based core being made of silicon oxide and lithium silicate; the negative electrode material is made into a slurry, and then a nanoparticle size and zeta potential analyzer is used to measure the zeta potential of the slurry, and a zeta potential distribution diagram of the slurry shows I1, I2 and I3 represents the form and content of the three materials on the surface of the anode material: carbon material, lithium silicate, and silicon oxide. That is, the surface of the anode material may contain a combination of materials such as lithium silicate, carbon material, and silicon oxide. When I1, I2, and I3 satisfy the following conditions: 0≦I2 / I1≦2.0 and 0≦I3 / I1≦1.0, the interfacial reaction between the anode material and the electrolyte is good, a high-speed mass and charge transfer interface is established between the anode material and the electrolyte, and the material charge conduction efficiency of the anode material and the rate performance of the anode material are improved. Controlling the solid-liquid reaction between the surface of the anode material and the electrolyte forms a stable SEI interface, reduces electrolyte decomposition, and suppresses cycle swelling of the anode pieces, thereby improving the cycle performance of the anode material.

[0020] In addition, in the zeta potential measurement distribution diagram of the negative electrode material slurry, if a complete peak shape is not formed within a region (the peak center is not within the region, or there is no peak within the entire region), the value with the highest intensity (total number) is selected and read as the intensity (total number) I value of that region.

[0021] Specifically, I2 / I1 may be, for example, 0, 0.1, 0.3, 0.5, 0.7, 0.8, 0.9, 1.0, 1.1, 1.3, 1.5, 1.7, 1.8, or 2.0, and is not limited thereto. Note that when I2 is 0, i.e., when the ratio of lithium silicate on the surface of the negative electrode material is 0, it indicates that the silicon-based core is almost completely covered with the coating layer. Specifically, I3 / I1 may be, for example, 0.1, 0.15, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0, and is not limited thereto.

[0022] It can be seen that when the I2 / I1 ratio is greater than 2, the charge ion distribution on the surface of the anode material becomes less rational, causing the surface of the anode material to change from diverse to monotonous. During the slurry preparation process, the zeta potential of the anode material changes, reducing the dispersibility of the slurry and generating gas. This causes excessive decomposition and deposition of the electrolyte on the anode strip during the electrochemical reaction, resulting in expansion of the strip, affecting the safety and cycling performance of the lithium-ion battery. By controlling the I2 / I1 ratio within the above range, the potential distribution on the surface of the anode material can be rationalized, resulting in a more diverse surface of the anode material. On the one hand, the anode material can achieve solid-liquid control during the slurry preparation process, suppress gas generation, and improve the dispersibility of the slurry. On the other hand, during the electrochemical reaction, the decomposition reaction and deposition pattern with the electrolyte can be controlled, the SEI interface can be stabilized, and the volume expansion of the material can be mitigated, thereby improving the cycling performance of the anode material and maximizing the electrochemical performance of the anode material. Furthermore, controlling the I2 / I1 ratio allows for control of the surface composition of the anode material, establishing a fast ion-electron transport path, improving the conductivity of the anode material, improving the material's rate performance, and reducing the loss of active silicon and active lithium. When the I3 / I1 ratio is within the range of 0≦I3 / I1≦1.0, the particle surface of the anode material has a certain hydrophilicity, facilitating particle processing and dispersion, and reducing phenomena such as aggregation and sedimentation during processing of the anode material. Furthermore, when the ratios 0≦I2 / I1≦2.0 and 0≦I3 / I1≦1.0 are simultaneously satisfied, the anode material achieves a balance between hydrophilicity and lipophilicity, further improving the processing performance and electrolyte infiltration efficiency of the anode material.

[0023] In some embodiments, the carbon material comprises at least one of graphite, amorphous carbon, diamond-like carbon, carbon fiber, and carbides.

[0024] In some embodiments, amorphous carbon includes soft carbon and hard carbon.

[0025] In some embodiments, the carbon material comprises silicon carbide.

[0026] In some embodiments, the coating layer material further comprises at least one of a nitride, a metal oxide, a phosphate, and a silicate.

[0027] In some embodiments, the nitride comprises at least one of silicon nitride, pyrrole, and pyridine.

[0028] In some embodiments, the metal oxide comprises at least one of titanium oxide, aluminum oxide, magnesium oxide, lithium oxide, zirconium oxide, cobalt oxide, and vanadium oxide.

[0029] In some embodiments, the phosphate salt comprises at least one of lithium phosphate, aluminum phosphate, lithium aluminum phosphate, lithium aluminum titanium phosphate, magnesium phosphate, lithium magnesium phosphate, calcium phosphate, lithium calcium phosphate, lithium dihydrogen phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and triammonium phosphate.

[0030] In some embodiments, the silicate comprises at least one of lithium silicate, magnesium silicate, aluminum silicate, magnesium aluminum silicate, lithium magnesium silicate, calcium silicate, magnesium calcium silicate, lithium calcium silicate, or lithium aluminum silicate.

[0031] In some embodiments, the thickness of the coating layer is from 20 nm to 700 nm. Specifically, it may be 20 nm, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm or 700 nm, etc. Of course, it may also be other values within the above range, and is not limited here. If the coating layer is too thick, the lithium ion transport efficiency will decrease, which is disadvantageous for the high-rate charge and discharge of the material, and will reduce the comprehensive performance of the anode material. If the coating layer is too thin, it is disadvantageous for increasing the conductivity of the anode material, and the performance of suppressing the volume expansion of the material is weak, resulting in poor long-term cycle performance.

[0032] In some embodiments, the silicate contains oxygen atoms and silicon atoms, and the molar ratio of oxygen atoms to silicon atoms is from 0 to 2. The silicate can be represented by the general formula SiOx (0 < x ≤ 2). The silicate may be a material in which silicon particles are dispersed in SiO2, or a material having a tetrahedral structural unit in which silicon atoms are located at the center of the tetrahedral structural unit and silicon atoms and oxygen atoms are located at the four vertices of the tetrahedral structural unit.

[0033] In some embodiments, the average particle size of the silicon-based core is from 2.0 μm to 10.0 μm. Specifically, it may be 2.0 μm, 3.0 μm, 4.0 μm, 5.0 μm, 6.0 μm, 7.0 μm, 8.0 μm, 9.0 μm or 10.0 μm, etc. Of course, it may also be other values within the above range, and is not limited here.

[0034] In some embodiments, the lithium content in the silicon-based core is 10 3 ppm to 10 5 ppm. Specifically, it may be 1000 ppm, 2000 ppm, 5000 ppm, 10000 ppm, 30000 ppm, 50000 ppm, 80000 ppm or 100000 ppm, etc. Of course, it may also be other values within the above range, and is not limited here.

[0035] In some embodiments, the general formula of the lithium silicate is Li2O-nSiO2 (0 < n ≦ 4). Specifically, the value of n may be, for example, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, or 4, without limitation here. Exemplarily, when the value of n is 1, the lithium silicate is Li2O·SiO2; when the value of n is 2, the lithium silicate is Li2O-2SiO2, and the description thereof is omitted here.

[0036] In some embodiments, at least a part of the lithium silicate is located on the surface of the silicate oxide, and the lithium silicate on the surface of the silicate oxide is scattered and distributed.

[0037] In some embodiments, the average particle size of the negative electrode material is 2 μm to 12 μm. Specifically, the average particle size of the negative electrode material may be, for example, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, or 12 μm, without limitation here. Controlling the average particle size of the negative electrode material within the above range is advantageous for improving the cycle performance of the negative electrode material. Preferably, the average particle size of the negative electrode material is 2.0 μm to 9.0 μm.

[0038] In some embodiments, the specific surface area of the negative electrode material is 0.5 m 2 / g to 8.0 m 2 / g. Specifically, it may be 0.5 m 2 / g, 1.0 m 2 / g, 2.0 m 2 / g, 3.0 m 2 / g, 4.0 m 2 / g, 5.0 m 2 / g, 6.0 m 2 / g, 7.0 m 2 / g, or 8.0 m 2 / g, and of course, it may also be other values within the above range, without limitation here. When the specific surface area of the negative electrode material is within the above range, the processing performance of the material is ensured, which is advantageous for improving the initial efficiency of the lithium battery manufactured with the negative electrode material and is also advantageous for improving the cycle characteristics of the negative electrode material. Preferably, the specific surface area of the negative electrode material is 1.0 m 2 / g to 4.0 m2 / g.

[0039] In some embodiments, the tap density of the negative electrode material is 0.5 g / cm 3 ~2.0g / cm 3 Specifically, 0.5 g / cm 3 , 0.7g / cm 3 , 0.9g / cm 3 , 1.0g / cm 3 , 1.2g / cm 3 , 1.5g / cm 3 , 1.6g / cm 3 , 1.7g / cm 3 , 1.8g / cm 3 , 1.9g / cm 3 or 2.0 g / cm 3 The tap density of the negative electrode material may be 0.7 g / cm or less, and of course, may be other values ​​within the above range, and is not limited thereto. A tap density of the negative electrode material within the above range is advantageous for improving the energy density of a lithium battery manufactured using the negative electrode material. Preferably, the tap density of the negative electrode material is 0.7 g / cm or less. 3 ~1.6g / cm 3 is.

[0040] In some embodiments, the mass content of water in the negative electrode material is 0.01% to 0.5%, and may be specifically 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, or 0.5%, or may be other values ​​within the above range, and is not limited thereto.

[0041] In some embodiments, when the mass of the negative electrode material is taken as 100%, the mass content of the carbon material is 0.5% to 10%, and specifically may be 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, etc., or may be other values ​​within the above range, and is not limited thereto. Preferably, the mass content of the carbon material in the negative electrode material is 2.5% to 8%.

[0042] In some embodiments, when the mass of the negative electrode material is taken as 100%, the lithium content in the negative electrode material is 2% to 15%, and may be specifically 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15%, etc., or may be other values ​​within the above range, and is not limited thereto.

[0043] In some embodiments, the pH value of the negative electrode material is 10.0 to 12.3, and may be specifically 10.0, 10.3, 10.5, 10.8, 11.0, 11.2, 11.5, 11.7, 11.9, 12.0, 12.1, 12.2, or 12.3. Of course, the pH value may be other values ​​within the above range, and is not limited thereto.

[0044] In a second aspect, the present embodiment provides a method for manufacturing a negative electrode material, as shown in FIG. 1, comprising the following steps: S100: A coating agent and a coating gas source containing a gaseous carbon source are used in combination to form a coating layer on the surface of a silicon-based core by vapor deposition to obtain a negative electrode material, wherein the coating agent is a non-vapor-phase coating agent having a benzene ring structure, and the silicon-based core contains silicon oxide and lithium silicate.

[0045] In some embodiments, the non-gas phase coating comprises a solid phase coating and / or a liquid phase coating.

[0046] The method for producing a negative electrode material according to the present application involves producing the negative electrode material by vapor-depositing a silicon-based core using a gas-phase carbon source, and then adding a solid-phase coating agent and / or a liquid-phase coating agent to carry out vapor-phase deposition. During the vapor-phase deposition process, different carbon sources have different dissociation efficiencies at the same temperature, and also different deposition efficiencies on the surface of the silicon-based core. As a result, different types of carbon sources are sequentially deposited on the surface of the silicon-based core, forming differentiated deposition on the surface of the silicon-based core. The carbon material formed by dissociation of the gas-phase carbon source is deposited on the surface of the silicon-based core to form a coating layer, and the carbon material formed by dissociation of the solid-phase coating agent and / or liquid-phase coating agent is deposited on the coating layer and is embedded in the coating layer. Because the solid-phase coating agent and / or liquid-phase coating agent have a benzene ring structure, the benzene ring structure is mainly derived from aromatic organic substances with low melting and boiling points. These organic substances can further perform surface modification and functional doping on the coating layer during the carbonization process, thereby optimizing the surface of the coating layer of the anode material, realizing control over the surface of the anode material, and further controlling the solid-liquid interfacial reaction between the anode material and the electrolyte, thereby improving the processing performance and cycle performance of the anode material.

[0047] The production method according to the present invention will now be described in detail.

[0048] In some embodiments, the step of preparing the silicon-based core comprises prelithiating a mixture comprising a silicate and a lithium source to obtain a prelithiated silicon-based core.

[0049] In some embodiments, the silicate is silicon monoxide.

[0050] In some embodiments, the lithium source comprises at least one of lithium hydride, alkyl lithium, metallic lithium, lithium aluminum hydride, lithium amide, lithium borohydride, and lithium silicon alloy.

[0051] In some embodiments, the mass ratio of the silicate to the lithium source may be (85-99):(1-15), specifically, 85:15, 88:12, 90:10, 92:8, 95:5, 96:4, 97:3, 98:2, or 99:1, etc., and of course, may be other values ​​within the above range, and is not limited thereto.

[0052] In some embodiments, the time for the prelithiation treatment is 0.5 hours to 24.0 hours, and specifically may be 0.5 hours, 1 hour, 3 hours, 5 hours, 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, or 24 hours, etc., and of course, may be other values ​​within the above range and are not limited thereto.

[0053] In some embodiments, the temperature of the prelithiation treatment is 300°C to 1000°C, and may be specifically 300°C, 400°C, 500°C, 600°C, 700°C, 800°C, 900°C, or 1000°C, or may be other values ​​within the above range, and is not limited thereto.

[0054] In some embodiments, the prelithiation process is carried out in an inert gas atmosphere containing at least one of helium gas, neon gas, argon gas, krypton gas, and xenon gas.

[0055] In some embodiments, before subjecting the mixture containing the silicate and the lithium source to a prelithiation treatment, the method further comprises the step of mixing the silicate and the lithium source and then performing a shaping treatment to obtain a mixture containing the silicate and the lithium source.

[0056] In some embodiments, the method further comprises the following steps before subjecting the mixture containing the silicate and the lithium source to a prelithiation treatment: After mixing the silicate and the lithium source, a shaping treatment is performed to obtain a mixture containing the silicate and the lithium source, and the shaping treatment comprises at least one of crushing, ball milling, grinding, and airflow grinding.

[0057] In some embodiments, prior to vapor deposition of the silicon-based core using a vapor-phase carbon source, the method further comprises the steps of: classifying the silicon-based core and then purifying it.

[0058] As can be seen, by classifying the silicon-based core, the particle size range of the silicon-based core can be controlled, and by controlling the particle size of the silicon-based core, the specific surface area and outer surface modification area of ​​the silicon-based core can be effectively controlled, which is beneficial to controlling the deposition efficiency of the negative electrode material and controlling the construction of the surface with diversified materials; by purifying the silicon-based core, a differentiated adsorption interface can be formed on the outer surface of the silicon-based core, and the coating layer can form a differentiated deposition during the deposition process, thereby controlling the surface, realizing surface synthesis control, and realizing preferred surface synthesis.

[0059] In some embodiments, the classification process comprises air classification.

[0060] In some embodiments, the average particle size of the silicon-based core is 2.0 μm to 10.0 μm, and may be specifically 2.0 μm, 3.0 μm, 4.0 μm, 5.0 μm, 6.0 μm, 7.0 μm, 8.0 μm, 9.0 μm, or 10.0 μm, or may be other values ​​within the above range, and is not limited thereto.

[0061] In some embodiments, the purification step includes placing the classified silicon-based core in a solvent to wash it and then drying it.

[0062] In some embodiments, the purification step comprises washing and drying the classified silicon-based core in a solvent, the solvent comprising at least one of ethanol, acetone, N,N-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, and ethylene glycol dimethyl ether.

[0063] In some embodiments, the purification step includes washing the classified silicon-based core in a solvent and drying, and the washing time is 2 hours to 10 hours. The washing time may be 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, or 10 hours, etc., and is not limited thereto.

[0064] In some embodiments, the purification step includes placing the classified silicon-based core in a solvent to wash and then drying, and the drying temperature is 45°C to 80°C, specifically, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C, etc., and of course, other values ​​within the above range may also be used, and are not limited thereto.

[0065] In some embodiments, the purification step includes placing the classified silicon-based core in a solvent to wash and then drying, and the drying time is 3 hours to 48 hours, specifically, 3 hours, 5 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 25 hours, 30 hours, 35 hours, 40 hours, 45 hours, or 48 hours, etc., and of course, other values ​​within the above range may also be used, and are not limited thereto.

[0066] In some embodiments, the gas phase carbon source feedstock comprises at least one of methane, ethane, ethylene, acetylene, propyne, propylene, propane, formaldehyde, acetaldehyde, methanol, toluene, benzene, styrene, and phenol.

[0067] In some embodiments, the flow rate of the gas phase carbon source is 200 mL / min to 5000 mL / min, and may be specifically 200 mL / min, 500 mL / min, 800 mL / min, 1000 mL / min, 2000 mL / min, 3000 mL / min, 4000 mL / min, 4500 mL / min, or 5000 mL / min, etc., and of course may be other values ​​within the above range and are not limited thereto.

[0068] In some embodiments, the deposition temperature for vapor deposition is 400°C to 1200°C, and may be, for example, 400°C, 500°C, 600°C, 700°C, 800°C, 900°C, 1000°C, 1100°C, or 1200°C. Of course, other values ​​within the above range are also possible and are not limited thereto. Controlling the deposition temperature within this range can control the decomposition efficiency of the vapor carbon source, control the deposition efficiency of the carbon material on the surface of the negative electrode active material, and control the volatilization efficiency of the solid-phase coating agent and liquid-phase coating agent, as well as the functional group retention efficiency. Controlling the deposition temperature within this temperature range can ensure that the size of silicon crystal grains is controlled within a certain range, ensure the degree of carbonization of the negative electrode material, reduce the proportion of C-H bonds in the negative electrode material, improve the conductivity of the carbon coating layer, and further improve the conductive performance of the negative electrode material.

[0069] In some embodiments, the deposition time of the vapor deposition is 1 hour to 24 hours. Specifically, the deposition time of the vapor deposition may be 1 hour, 3 hours, 5 hours, 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, or 24 hours, etc., and is not limited thereto. As can be understood, if the deposition time of the vapor deposition is too long, the coating layer is likely to be too thick, and if the deposition time of the vapor deposition is too short, the coating layer is likely to be too thick. Controlling the deposition time within the above range allows for control of the thickness of the coating layer, which is advantageous for controlling the thickness of the coating layer within an ideal range.

[0070] In some embodiments, the deposition pressure of the vapor deposition is 10 KPa to 0.1 MPa, and specifically, may be 10 KPa, 20 KPa, 30 KPa, 40 KPa, 50 KPa, 60 KPa, 70 KPa, 80 KPa, 90 KPa, or 0.1 MPa, etc., but is not limited thereto. By controlling the deposition pressure within the above range, the density of the coating layer can be controlled, and the coating layer can have good density, improving the stability and cycle performance of the negative electrode material.

[0071] In some embodiments, an auxiliary carrier gas is further added during the vapor deposition process. As can be seen, the auxiliary carrier gas can be used to introduce solid and / or liquid coating materials into a vapor deposition furnace for vapor deposition, and the solid and / or liquid coating materials can be deposited into a coating layer during the deposition process, thereby surface-modifying and functionally doping the coating layer of the negative electrode material, thereby optimizing the surface interface and controlling the material surface. The auxiliary carrier gas can also accelerate the decomposition of the carbon source, improving the decomposition rate of the carbon source and the vapor deposition rate. The auxiliary carrier gas can increase the terminal structure of the carbon chain, thereby depositing different types of carbon materials on the surface of the negative electrode material and optimizing the pore environment of the negative electrode material.

[0072] In some embodiments, the vapor deposition process further includes the addition of a supplemental carrier gas comprising at least one of H2, CO2, NH3, and Ar.

[0073] In some embodiments, an auxiliary carrier gas is further added during the vapor deposition process, and the flow rate of the auxiliary carrier gas is 100 mL / min to 8000 mL / min, specifically, 100 mL / min, 500 mL / min, 1000 mL / min, 2000 mL / min, 3000 mL / min, 4000 mL / min, 5000 mL / min, 6000 mL / min, 7000 mL / min, or 8000 mL / min, etc., and of course, other values ​​within the above range are also possible and are not limited here.

[0074] In some embodiments, an auxiliary carrier gas is further added during the vapor deposition process, and the flow ratio of the gaseous carbon source to the auxiliary carrier gas is (3-9.5):(0.5-7), and may be specifically 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1, or 9.5:0.5, etc., and may also be other values ​​within the above range, and are not limited thereto.

[0075] In some embodiments, an auxiliary carrier gas is further added during the vapor deposition process, and the volume ratio of the gaseous carbon source to the auxiliary carrier gas is (3-9.5):(0.5-7), specifically, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1, or 9.5:0.5, etc., and of course, other values ​​within the above range are also possible and are not limited thereto.

[0076] In some embodiments, vapor deposition is performed in a deposition chamber of a vapor deposition apparatus, and the rotation speed of the deposition chamber is 0.1 r / min to 10 r / min, specifically, 0.1 r / min, 0.5 r / min, 1 r / min, 2 r / min, 3 r / min, 4 r / min, 5 r / min, 6 r / min, 7 r / min, 8 r / min, 9 r / min, or 10 r / min, etc., and may be other values ​​within the above range, without limitation. Controlling the rotation speed of the deposition chamber within the above range is advantageous for improving deposition coating uniformity among negative electrode material particles.

[0077] In some embodiments, the solid coating agent is selected from the group consisting of tetracarboxylic acid anhydrides, copper phthalocyanines, substituted or unsubstituted naphthalenes, substituted or unsubstituted anthracenes, substituted or unsubstituted phenanthrenes, substituted or unsubstituted pyrenes, substituted or unsubstituted biphenyls, substituted or unsubstituted terphenyls, C 60 or substituted or unsubstituted phenalene.

[0078] In some embodiments, the liquid phase coating comprises at least one of toluene, xylene, styrene, ethylene glycol dimethyl ether, or butyl toluene.

[0079] In some embodiments, the method further comprises classifying and drying the reaction product of the vapor deposition.

[0080] As can be seen, classifying the reaction product of vapor deposition is advantageous for dispersing powder agglomerates of the negative electrode material and controlling the average particle size of the negative electrode material within a preferred range. Drying the reaction product of vapor deposition removes moisture from the negative electrode material, which is advantageous for improving the electrochemical performance of the negative electrode material.

[0081] In some embodiments, the average particle size of the negative electrode material is 2 μm to 12 μm. Specifically, the average particle size of the negative electrode material may be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, or 12 μm, etc., but is not limited thereto. Preferably, the average particle size of the negative electrode material is 2 μm to 9 μm.

[0082] In some embodiments, the temperature of the drying treatment is 50°C to 120°C, and specifically may be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 110°C, or 120°C, or may be other values ​​within the above range, and is not limited thereto.

[0083] In some embodiments, the drying time is 6.0 hours to 48.0 hours, and may be specifically 6 hours, 12 hours, 15 hours, 18 hours, 20 hours, 24 hours, 30 hours, 36 hours, 40 hours, 45 hours, or 48 hours, etc., and of course, may be other values ​​within the above range and are not limited here.

[0084] In some embodiments, the method further includes solid-phase or liquid-phase mixing of the product of the vapor deposition with a coating material comprising at least one of a nitride, a metal oxide, a phosphate, and a silicate.

[0085] In some embodiments, the step of solid-state mixing the product of vapor deposition and the coating material comprises grinding and heat treating the mixture comprising the product of vapor deposition and the coating material.

[0086] In some embodiments, the step of solid-state mixing the vapor deposition product and the coating material includes polishing and heat-treating the mixture containing the vapor deposition product and the coating material, and the polishing time is 0.5 hours to 48 hours, specifically, 0.5 hours, 1 hour, 3 hours, 8 hours, 12 hours, 15 hours, 18 hours, 24 hours, 36 hours, 40 hours, 45 hours, or 48 hours, etc., and is not limited thereto.

[0087] In some embodiments, the step of solid-state mixing the vapor deposition product and the coating material includes grinding and heat-treating the mixture including the vapor deposition product and the coating material, wherein the heat-treatment temperature is 400°C to 1000°C and the heat-treatment time is 1.0 h to 24.0 h.

[0088] Specifically, the heat treatment temperature may be, but is not limited to, 400°C, 450°C, 500°C, 600°C, 800°C, 900°C, 1000°C, etc. The heat treatment time may be, but is not limited to, 1 hour, 3 hours, 5 hours, 8 hours, 12 hours, 15 hours, 18 hours, 20 hours, 24 hours, etc.

[0089] In some embodiments, the step of solid-state mixing the product of vapor deposition and the coating material includes grinding and heat-treating the mixture including the product of vapor deposition and the coating material, wherein the heat-treating is performed in a protective atmosphere including at least one of nitrogen gas, helium gas, argon gas, neon gas, and krypton gas.

[0090] In some embodiments, the step of liquid-phase mixing the product of vapor deposition and the coating material includes drying and heat-treating the mixed coating liquid including the product of vapor deposition and the coating material.

[0091] In some embodiments, the step of liquid-phase mixing the product of vapor deposition and the coating material includes drying and heat-treating the mixed coating liquid including the product of vapor deposition and the coating material, wherein the mixed coating liquid includes a polar solvent.

[0092] In some embodiments, the step of liquid-phase mixing the product of vapor deposition and the coating material includes drying and heat-treating the mixed coating liquid including the product of vapor deposition and the coating material, wherein the polar solvent includes at least one of water, absolute ethanol, methanol, and isopropanol.

[0093] In some embodiments, the step of liquid-phase mixing the vapor deposition product and the coating material includes drying and heat-treating the mixed coating liquid containing the vapor deposition product and the coating material, wherein the drying temperature is 50°C to 120°C and the drying time is 6 hours to 48 hours.

[0094] In some embodiments, the step of liquid-phase mixing the vapor deposition product and the coating material includes drying and heat-treating the mixed coating liquid containing the vapor deposition product and the coating material, wherein the heat-treatment temperature is 80°C to 150°C and the heat-treatment time is 3.0 h to 48.0 h.

[0095] Specifically, the heat treatment temperature may be, but is not limited to, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, or 150°C. The heat treatment time may be, but is not limited to, 3 hours, 5 hours, 8 hours, 12 hours, 15 hours, 18 hours, 24 hours, 30 hours, 36 hours, 45 hours, or 48 hours.

[0096] In some embodiments, the step of liquid-phase mixing the product of vapor deposition and the coating material includes drying and heat-treating the mixed coating liquid containing the product of vapor deposition and the coating material, and the heat-treatment is performed in a protective atmosphere containing at least one of nitrogen gas, helium gas, argon gas, neon gas, and krypton gas.

[0097] In a third aspect, the present application provides a lithium-ion battery comprising the negative electrode material according to the first aspect, or the negative electrode material produced by the method for producing the negative electrode material according to the second aspect. [Example]

[0098] Example 1 (1) 200 g of lithium hydride and 1800 g of silicon monoxide were mixed, then placed in a vacuum ball mill and subjected to vacuum dry ball milling for 60 minutes to obtain a mixture containing lithium hydride and silicon monoxide. The mixture was then placed in an atmospheric heat treatment device, argon gas was introduced, and prelithiation treatment was carried out at 1000°C for 12 hours to obtain silicon-based cores. Finally, the silicon-based cores were subjected to air flow classification until the average particle size reached 5.0 μm. (2) 1000 g of silicon-based cores (average particle size 5.0 μm) were weighed, washed with deionized water for 30 minutes, then washed with ethanol, immersed in ethanol for 3 hours, and placed in a vacuum drying box and dried at 80°C for 24 hours. (3) The obtained sample was placed in the deposition chamber of a vapor deposition furnace, and a 1:1:1 volume ratio of methane, acetylene, and ethylene gases was introduced into the deposition chamber as a vapor-phase carbon source at a rate of 1000 mL / min. At the same time, tetracarboxylic acid anhydride (PTCDA), a solid-phase coating agent, was placed at the tip of the vapor deposition furnace. The pressure in the deposition chamber was adjusted using a pressure valve, and after the reaction chamber was evacuated, Ar was introduced as an auxiliary carrier gas at a rate of 1000 mL / min. Vapor deposition was then carried out at 450 °C for 10 h. Here, the flow ratio of the vapor-phase carbon source to Ar was 1:1, the rotation speed of the deposition chamber was 5 r / min, and the deposition pressure was 0.05 MPa. (4) The vapor-phase deposition product was classified and then placed in a vacuum drying box and dried at 100°C for 24 hours to obtain the negative electrode material.

[0099] The negative electrode material produced in this example includes a silicon-based core including silicon oxide and lithium silicate, and a carbon coating layer located on at least a portion of the active material.

[0100] 20 mg of the negative electrode material was added to 10 ml of deionized water to form a slurry, and the zeta potential of the slurry was measured using a nanoparticle size and zeta potential analyzer. In the zeta potential measurement distribution diagram of the slurry, as shown in FIG. 2, the maximum intensity I1 of the first characteristic peak in the zeta potential range of -50 mV to -40 mV of the slurry was 78769, the maximum intensity I2 of the second characteristic peak in the zeta potential range of -65 mV to -50 mV was 98739, and the maximum intensity I3 of the third characteristic peak in the zeta potential range of -35 mV to -25 mV was 38278, and the I2 / I1 ratios were 1.25 and 0.486, respectively.

[0101] The average particle size of the negative electrode material is 4.92 μm, and the specific surface area is 1.57 m 2 / g, tap density is 0.98g / cm 3 The mass content of carbon element in the negative electrode material is 4.93%. When the mass of the negative electrode material is 100%, the mass content of lithium in the negative electrode material is 9.55%, and the mass content of water is 0.21%.

[0102] Example 2 (1) 200 g of lithium hydride and 1800 g of silicon monoxide were mixed, then placed in a vacuum ball mill and subjected to vacuum dry ball milling for 60 minutes to obtain a mixture containing lithium hydride and silicon monoxide. The mixture was then placed in an atmospheric heat treatment device, argon gas was introduced, and prelithiation treatment was carried out at 1000°C for 12 hours to obtain silicon-based cores. Finally, the silicon-based cores were subjected to air flow classification until the average particle size reached 5.0 μm. (2) 1000 g of silicon-based cores (average particle size 5.0 μm) were weighed, washed with deionized water for 30 minutes, then washed with acetone, immersed in acetone for 3 hours, and placed in a vacuum drying box and dried at 80°C for 24 hours. (3) The obtained sample was placed in the deposition chamber of a vapor deposition furnace, and methane gas was introduced into the deposition chamber at 1000 mL / min as the gaseous carbon source. At the same time, copper phthalocyanine, a solid-phase coating agent, was placed at the tip of the vapor deposition furnace. The pressure in the deposition chamber was adjusted using a pressure valve, and after the reaction chamber was evacuated, Ar and NH3 were introduced as auxiliary carrier gases at a volume ratio of 5:1 at 500 mL / min. Vapor deposition was then carried out for 12 hours at 500 °C. Here, the flow ratio of the gaseous carbon source to the auxiliary carrier gas (Ar and NH3) was 2:1, the rotation speed of the deposition chamber was 5 r / min, and the deposition pressure was 0.03 MPa. (4) The vapor-phase deposition product was classified and then placed in a vacuum drying box and dried at 100°C for 24 hours to obtain the negative electrode material.

[0103] The negative electrode material produced in this example includes a silicon-based core including silicon oxide and lithium silicate, and a carbon coating layer located on at least a portion of the silicon-based core.

[0104] 20 mg of the negative electrode material was added to 10 ml of deionized water to form a slurry, and the zeta potential of the slurry was measured using a nanoparticle size and zeta potential analyzer. In the zeta potential measurement distribution diagram of the slurry, as shown in FIG. 3, the maximum intensity I1 of the first characteristic peak in the zeta potential range of -50 mV to -40 mV of the slurry was 179809, the maximum intensity I2 of the third characteristic peak in the zeta potential range of -65 mV to -50 mV was 21756, and the maximum intensity I3 of the third characteristic peak in the zeta potential range of -35 mV to -25 mV was 36206, and the I2 / I1 ratios were 0.121 and 0.201, respectively.

[0105] The average particle size of the negative electrode material is 5.1 μm and the specific surface area is 1.72 m 2 / g, tap density is 0.99g / cm 3 The mass content of carbon element in the negative electrode material is 5.12%. When the mass of the negative electrode material is 100%, the mass content of lithium in the negative electrode material is 9.13% and the mass content of water is 0.11%.

[0106] Example 3 (1) 160 g of lithium hydride and 1840 g of silicon monoxide were mixed, then placed in a vacuum ball mill and subjected to vacuum dry ball milling for 60 minutes to obtain a mixture containing lithium hydride and silicon monoxide. The mixture was then placed in an atmospheric heat treatment device, argon gas was introduced, and prelithiation treatment was carried out at 1000°C for 12 hours to obtain silicon-based cores. Finally, the silicon-based cores were subjected to air flow classification until the average particle size reached 5.0 μm. (2) 1000 g of silicon-based cores (average particle size 5.0 μm) were weighed, washed with deionized water for 30 minutes, then washed with N,N-dimethylformamide, immersed in it for 1 hour, and then placed in a vacuum drying box and dried at 80°C for 24 hours. (3) The obtained sample was placed in the deposition chamber of a vapor deposition furnace. A 1:1:1:3 volume ratio of methane, acetylene, ethylene, and propane gases was introduced into the deposition chamber as the gaseous carbon source at a rate of 1500 mL / min. At the same time, toluene, a liquid coating agent, was placed at the tip of the vapor deposition furnace. The pressure in the deposition chamber was adjusted using a pressure valve. After the reaction chamber was evacuated, Ar and NH3 were introduced as auxiliary carrier gases at a volume ratio of 5:1 at a rate of 500 mL / min. Vapor deposition was then carried out at 800 °C for 8 h. The flow ratio of the gaseous carbon source to the auxiliary carrier gas (Ar and NH3) was 3:1, the chamber rotation speed was 5 r / min, and the deposition pressure was atmospheric. (4) The vapor-phase deposition product was classified and then placed in a vacuum drying box and dried at 100°C for 24 hours to obtain the negative electrode material.

[0107] The negative electrode material produced in this example includes an active material and a carbon coating layer located on at least a portion of the silicon-based core, the silicon-based core including silicon oxide and lithium silicate.

[0108] 20 mg of the negative electrode material was added to 10 ml of deionized water to form a slurry, and the zeta potential of the slurry was measured using a nanoparticle size and zeta potential analyzer. In the zeta potential measurement distribution diagram of the slurry, as shown in FIG. 4, the maximum intensity I1 of the first characteristic peak in the zeta potential range of -50 mV to -40 mV of the slurry was 97941, the maximum intensity I2 of the second characteristic peak in the zeta potential range of -65 mV to -50 mV was 44480, and the maximum intensity I3 of the third characteristic peak in the zeta potential range of -35 mV to -25 mV was 67448, and the I2 / I1 ratios were 0.45 and 0.689, respectively.

[0109] The average particle size of the negative electrode material is 5.1 μm and the specific surface area is 1.29 m 2 / g, tap density is 0.97g / cm 3 The mass content of carbon element in the negative electrode material is 4.98%. When the mass of the negative electrode material is 100%, the mass content of lithium in the negative electrode material is 7.13%, and the mass content of water is 0.17%.

[0110] Example 4 The difference from Example 1 is that the deposition temperature is 600° C. in the vapor deposition process.

[0111] The negative electrode material produced in this example includes a silicon-based core including silicon oxide and lithium silicate, and a carbon coating layer located on at least a portion of the silicon-based core.

[0112] 20 mg of the negative electrode material was added to 10 ml of deionized water to form a slurry, and the zeta potential of the slurry was measured using a nanoparticle size and zeta potential analyzer. In the zeta potential measurement distribution diagram of the slurry, as shown in FIG. 5, the maximum intensity I1 of the first characteristic peak in the zeta potential range of -50 mV to -40 mV of the slurry was 159,008, the maximum intensity I2 of the second characteristic peak in the zeta potential range of -65 mV to -50 mV was 50,380, and the maximum intensity I3 of the third characteristic peak in the zeta potential range of -35 mV to -25 mV was 64,524, and the I2 / I1 ratios were 0.317 and 0.406, respectively.

[0113] The average particle size of the negative electrode material is 5.12 μm and the specific surface area is 1.58 m 2 / g, tap density is 1.02g / cm 3 The mass content of carbon element in the negative electrode material is 4.99%. When the mass of the negative electrode material is taken as 100%, the mass content of lithium in the negative electrode material is 9.04% and the mass content of water is 0.21%.

[0114] Example 5 The difference from Example 1 is that the deposition temperature is 900° C. in the vapor deposition process.

[0115] The negative electrode material produced in this example includes a silicon-based core and a carbon coating layer located on at least a portion of the silicon-based core, and the active material includes silicon oxide and lithium silicate.

[0116] 20 mg of the negative electrode material was added to 10 ml of deionized water to form a slurry, and the zeta potential of the slurry was measured using a nanoparticle size and zeta potential analyzer. In the zeta potential measurement distribution diagram of the slurry, as shown in FIG. 6, the maximum intensity I1 of the first characteristic peak in the zeta potential range of -50 mV to -40 mV of the slurry was 76042, the maximum intensity I2 in the zeta potential range of -65 mV to -50 mV was 32434, and the maximum intensity I3 in the zeta potential range of -35 mV to -25 mV was 23691, and I2 / I1 = 0.427 and I3 / I1 = 0.312.

[0117] The average particle size of the negative electrode material is 5.0 μm and the specific surface area is 1.49 m 2 / g, tap density is 0.98g / cm 3 The mass content of carbon element in the negative electrode material is 5.19%. When the mass of the negative electrode material is taken as 100%, the mass content of lithium in the negative electrode material is 9.36%, and the mass content of water is 0.09%.

[0118] Example 6 (1) 200 g of lithium hydride and 1800 g of silicon monoxide were mixed, then placed in a vacuum ball mill and subjected to vacuum dry ball milling for 60 minutes to obtain a mixture containing lithium hydride and silicon monoxide. The mixture was then placed in an atmospheric heat treatment device, argon gas was introduced, and prelithiation treatment was carried out at 1000°C for 12 hours to obtain silicon-based cores. Finally, the silicon-based cores were subjected to air flow classification until the average particle size reached 5.0 μm. (2) 1000 g of silicon-based cores (average particle size 5.0 μm) were weighed, washed with deionized water for 30 minutes, then washed with acetone, immersed in acetone for 3 hours, and placed in a vacuum drying box and dried at 80°C for 24 hours. (3) The obtained sample was placed in the deposition chamber of a vapor deposition furnace. At the same time, liquid pitch, a liquid coating agent, was placed at the tip of the vapor deposition furnace. The pressure in the deposition chamber was adjusted using a pressure valve. After the reaction chamber was evacuated, acetylene gas was introduced into the deposition chamber at a rate of 1000 mL / min as the vapor carbon source, and Ar and NH3 were introduced at a volume ratio of 1:3 as the auxiliary carrier gas at a rate of 3000 mL / min. Vapor deposition was then carried out at 700 °C for 12 h. Here, the flow ratio of the vapor carbon source to the auxiliary carrier gas (Ar and NH3) was 1:3, the rotation speed of the deposition chamber was 5 r / min, and the deposition pressure was 0.05 MPa. (4) The vapor-phase deposition product was classified and then placed in a vacuum drying box and dried at 100°C for 24 hours to obtain the negative electrode material.

[0119] The negative electrode material produced in this example includes a silicon-based core containing silicon oxide and lithium silicate, and a carbon coating layer located on at least a portion of the surface of the silicon-based core, and the carbon coating layer is doped with a large amount of nitrogen.

[0120] 20 mg of the negative electrode material was added to 10 ml of deionized water to form a slurry, and the zeta potential of the slurry was measured using a nanoparticle size and zeta potential analyzer. In the zeta potential measurement distribution diagram of the slurry, the maximum intensity I1 of the first characteristic peak in the zeta potential range of -50 mV to -40 mV of the slurry was 113024, the maximum intensity I2 of the second characteristic peak in the zeta potential range of -65 mV to -50 mV was 89211, and the maximum intensity I3 of the third characteristic peak in the zeta potential range of -35 mV to -25 mV was 21157, with I2 / I1 = 0.789 and I3 / I1 = 0.187.

[0121] The average particle size of the negative electrode material is 5.04 μm and the specific surface area is 1.68 m 2 / g, tap density is 1.03g / cm 3The mass content of carbon element in the negative electrode material is 4.87%. When the mass of the negative electrode material is taken as 100%, the mass content of lithium in the negative electrode material is 9.02%, and the mass content of water is 0.19%.

[0122] Example 7 Differences from Example 2: The following step was further included before step (4): 65 g of aluminum chloride was weighed and dissolved in 2000 g of deionized water, and the mixture was stirred for 30 minutes. After the aluminum chloride was completely dissolved, 970 g of the vapor-deposited product was added, and the mixture was stirred for 120 minutes. After that, the mixture was centrifuged to remove the solvent, and the centrifuged product was vacuum-dried at 80°C for 48 hours. (5) After drying, the sample was placed in an argon gas atmosphere and heat-treated at 600°C for 12 hours, and then classified to obtain the negative electrode material.

[0123] The negative electrode material produced in this example includes a silicon-based core and a coating layer located on at least a portion of the surface of the silicon-based core, the silicon-based core including silicon oxide and lithium silicate, and the coating layer including a carbon material and aluminum oxide.

[0124] 20 mg of the negative electrode material was added to 10 ml of deionized water to form a slurry, and the zeta potential of the slurry was measured using a nanoparticle size and zeta potential analyzer. In the zeta potential measurement distribution diagram of the slurry, the maximum intensity I1 of the first characteristic peak in the zeta potential range of -50 mV to -40 mV of the slurry was 121743, the maximum intensity I2 of the second characteristic peak in the zeta potential range of -65 mV to -50 mV was 0, and the maximum intensity I3 of the third characteristic peak in the zeta potential range of -35 mV to -25 mV was 57192, and I2 / I1 = 0 and I3 / I1 = 0.470.

[0125] The average particle size of the negative electrode material is 4.93 μm and the specific surface area is 2.01 m 2 / g, tap density is 1.01g / cm 3The mass content of carbon element in the negative electrode material is 0.22%. When the mass of the negative electrode material is 100%, the mass content of lithium in the negative electrode material is 9.11% and the mass content of water is 0.08%.

[0126] Example 8 The difference from Example 2 is that (4) the product of vapor deposition was placed in a vacuum drying box and dried at 100°C for 24 hours. After step (4), the method further includes the following steps: 970 g of the dried vapor-phase deposition product, 25 g of aluminum oxide, and 5 g of lithium fluoride were weighed and uniformly mixed to form a mixture, which was then placed in a vacuum ball mill and subjected to vacuum dry ball milling for 6 hours, and the ball-milled mixture was heat-treated at 900°C in an argon gas atmosphere for 24 hours, followed by classification to obtain a negative electrode material.

[0127] The negative electrode material produced in this example includes a silicon-based core and a coating layer located on at least a portion of the silicon-based core, wherein the silicon-based core includes silicon oxide and lithium silicate, and the coating layer includes lithium silicate and aluminum silicate.

[0128] 20 mg of the negative electrode material was added to 10 ml of deionized water to form a slurry, and the zeta potential of the slurry was measured using a nanoparticle size and zeta potential analyzer. In the zeta potential measurement distribution diagram of the slurry, the maximum intensity I1 of the first characteristic peak in the zeta potential range of -50 mV to -40 mV of the slurry was 102959, the maximum intensity I2 of the second characteristic peak in the zeta potential range of -65 mV to -50 mV was 0, and the maximum intensity I3 of the third characteristic peak in the zeta potential range of -35 mV to -25 mV was 23009, and I2 / I1 = 0 and I3 / I1 = 0.223.

[0129] The average particle size of the negative electrode material is 5.00 μm and the specific surface area is 1.91 m 2 / g, tap density is 0.96g / cm 3The mass content of carbon element in the negative electrode material is 0.18%. When the mass of the negative electrode material is taken as 100%, the mass content of lithium in the negative electrode material is 9.01% and the mass content of water is 0.07%.

[0130] Example 9 The difference from Example 1 is that in step (1), the silicon-based core is air-flow pulverized until the average particle size becomes 2.0 μm, and the subsequent operations are the same as in Example 1.

[0131] The negative electrode material produced in this example includes a silicon-based core including silicon oxide and lithium silicate, and a carbon coating layer located on at least a portion of the active material.

[0132] 20 mg of the negative electrode material was added to 10 ml of deionized water to form a slurry, and the zeta potential of the slurry was measured using a nanoparticle size and zeta potential analyzer. In the zeta potential measurement distribution diagram of the slurry, the maximum intensity I1 of the first characteristic peak in the zeta potential range of -50 mV to -40 mV of the slurry was 63788, the maximum intensity I2 of the second characteristic peak in the zeta potential range of -65 mV to -50 mV was 103392, and the maximum intensity I3 of the third characteristic peak in the zeta potential range of -35 mV to -25 mV was 29303, and the I2 / I1 ratios were 1.62 and 0.46, respectively.

[0133] The average particle size of the negative electrode material is 2.07 μm and the specific surface area is 2.45 m 2 / g, tap density is 1.18g / cm 3 The mass content of carbon element in the negative electrode material is 5.12%. When the mass of the negative electrode material is 100%, the mass content of lithium in the negative electrode material is 9.67%, and the mass content of water is 0.17%.

[0134] Example 10 The difference from Example 1 is that in step (1), the silicon-based core is air-flow pulverized until the average particle size becomes 10.0 μm, and the subsequent operations are the same as in Example 1.

[0135] The negative electrode material produced in this example includes a silicon-based core including silicon oxide and lithium silicate, and a carbon coating layer located on at least a portion of the active material.

[0136] 20 mg of the negative electrode material was added to 10 ml of deionized water to form a slurry, and the zeta potential of the slurry was measured using a nanoparticle size and zeta potential analyzer. In the zeta potential measurement distribution diagram of the slurry, the maximum intensity I1 of the first characteristic peak in the zeta potential range of -50 mV to -40 mV of the slurry was 72129, the maximum intensity I2 of the second characteristic peak in the zeta potential range of -65 mV to -50 mV was 2309, and the maximum intensity I3 of the third characteristic peak in the zeta potential range of -35 mV to -25 mV was 52118, and I2 / I1 = 0.03 and I3 / I1 = 0.72.

[0137] The average particle size of the negative electrode material is 9.83 μm and the specific surface area is 1.76 m 2 / g, tap density is 0.98g / cm 3 The mass content of carbon element in the negative electrode material is 4.96%. When the mass of the negative electrode material is 100%, the mass content of lithium in the negative electrode material is 9.53%, and the mass content of water is 0.05%.

[0138] Example 11 The difference from Example 1 is that in step (1), 5 g of metallic lithium and 95 g of silicon monoxide are mixed, and the subsequent operations are the same as in Example 1.

[0139] The negative electrode material produced in this example includes a silicon-based core including silicon oxide and lithium silicate, and a carbon coating layer located on at least a portion of the active material.

[0140] 20 mg of the negative electrode material was added to 10 ml of deionized water to form a slurry, and the zeta potential of the slurry was measured using a nanoparticle size and zeta potential analyzer. In the zeta potential measurement distribution diagram of the slurry, the maximum intensity I1 of the first characteristic peak in the zeta potential range of -50 mV to -40 mV of the slurry was 55192, the maximum intensity I2 of the second characteristic peak in the zeta potential range of -65 mV to -50 mV was 39180, and the maximum intensity I3 of the third characteristic peak in the zeta potential range of -35 mV to -25 mV was 10732, and the I2 / I1 ratios were 0.71 and 0.19, respectively.

[0141] The average particle size of the negative electrode material is 4.93 μm and the specific surface area is 1.92 m 2 / g, tap density is 0.98g / cm 3 The mass content of carbon element in the negative electrode material is 5.10%. When the mass of the negative electrode material is 100%, the mass content of lithium in the negative electrode material is 5.02% and the mass content of water is 0.02%.

[0142] Comparative Example 1 (1) 200 g of lithium hydride and 1800 g of silicon monoxide were mixed, then placed in a vacuum ball mill and subjected to vacuum dry ball milling for 60 minutes to obtain a mixture containing lithium hydride and silicon monoxide. The mixture was then placed in an atmospheric heat treatment device, argon gas was introduced, and prelithiation treatment was carried out at 1000°C for 12 hours to obtain silicon-based cores. Finally, the silicon-based cores were subjected to air flow classification until the average particle size reached 5.0 μm. (2) 1000 g of silicon-based cores (average particle size 5.0 μm) were weighed, washed with deionized water for 30 minutes, placed in a vacuum drying box, and dried at 100° C. for 24 hours to obtain a negative electrode material.

[0143] The negative electrode material produced in this comparative example includes a silicon-based core that includes silicon oxide and lithium silicate located on at least a portion of the surface of the silicon oxide.

[0144] 20 mg of the negative electrode material was added to 10 ml of deionized water to form a slurry, and the zeta potential of the slurry was measured using a nanoparticle size and zeta potential analyzer. In the zeta potential measurement distribution diagram of the slurry, as shown in FIG. 7, the maximum intensity I1 of the slurry within the zeta potential range of -50 mV to -40 mV was 1731, the maximum intensity I2 of the second characteristic peak within the zeta potential range of -65 mV to -50 mV was 112791, and the maximum intensity I3 of the third characteristic peak within the zeta potential range of -35 mV to -25 mV was 41337, with I2 / I1 = 65.16 and I3 / I1 = 13.27.

[0145] The average particle size of the negative electrode material is 5.0 μm and the specific surface area is 1.31 m 2 / g, tap density is 0.98g / cm 3 The mass content of carbon element in the negative electrode material is 0.33%. When the mass of the negative electrode material is 100%, the mass content of lithium in the negative electrode material is 10.31% and the mass content of water is 0.32%.

[0146] Comparative Example 2 (1) 200 g of lithium hydride and 1800 g of silicon monoxide were mixed, then placed in a vacuum ball mill and subjected to vacuum dry ball milling for 60 minutes to obtain a mixture containing lithium hydride and silicon monoxide. The mixture was then placed in an atmospheric heat treatment device, argon gas was introduced, and prelithiation treatment was carried out at 1000°C for 12 hours to obtain silicon-based cores. Finally, the silicon-based cores were subjected to air flow classification until the average particle size reached 5.0 μm. (2) 1000 g of silicon-based cores (average particle size 5.0 μm) were weighed, washed with deionized water for 30 minutes, and then placed in a vacuum drying box and dried at 100°C for 24 hours. (3) The obtained sample was placed in the deposition chamber of a vapor deposition furnace, and methane gas was introduced into the deposition chamber as a gaseous carbon source. Then, vapor deposition was carried out at 900 °C for 4 h. Here, the rotation speed of the deposition chamber was 5 r / min, and the deposition pressure was 0.05 MPa. (4) The vapor-phase deposition product was classified and then placed in a vacuum drying box and dried at 100°C for 24 hours to obtain the negative electrode material.

[0147] The negative electrode material produced in this comparative example includes a silicon-based core and a carbon coating layer located on at least a portion of the surface of the silicon-based core, and the silicon-based core includes a silicon oxide and a lithium silicate located on at least a portion of the surface of the silicon oxide.

[0148] 20 mg of the negative electrode material was added to 10 ml of deionized water to form a slurry, and the zeta potential of the slurry was measured using a nanoparticle size and zeta potential analyzer. In the zeta potential measurement distribution diagram of the slurry, as shown in FIG. 8, the maximum intensity I1 of the first characteristic peak in the zeta potential range of -50 mV to -40 mV of the slurry was 43212, the maximum intensity I2 of the second characteristic peak in the zeta potential range of -65 mV to -50 mV was 132771, and the maximum intensity I3 of the third characteristic peak in the zeta potential range of -35 mV to -25 mV was 34179, and the I2 / I1 ratios were 3.07 and 1.26, respectively.

[0149] The average particle size of the negative electrode material is 5.0 μm and the tap density is 0.98 g / cm 3 , specific surface area is 1.59m 2 / g, the mass content of carbon element in the negative electrode material is 4.54%, and when the mass of the negative electrode material is 100%, the mass content of lithium in the negative electrode material is 9.33%, and the mass content of water is 0.21%.

[0150] Measurement method (1) Method for measuring particle size of negative electrode material: The particle size of the anode material is measured using a Malvern Mastersizer 2000 laser diffraction particle size analyzer to obtain the average particle size. (2) Measurement method for the specific surface area of ​​the negative electrode material: Measurements were taken using a high-speed dynamic specific surface area measuring instrument JW-DX manufactured by Beijing Jingwei Gaobo Science and Technology Co., Ltd. The unit of specific surface area is m 2 / g. (3) Method for measuring tap density of negative electrode material: A certain amount of sample is weighed using a Baxter tap density measuring instrument, and the tap density is measured by vibrating 3,000 times at 300 times / min. (4) Method for measuring the mass content of water in negative electrode material: The mass content of water in the negative electrode material is measured using a thermogravimetric method, and the specific gravity of the total weight of the mass loss of the negative electrode material at 250°C is the mass content of water in the negative electrode material. (5)Method for measuring lithium content in negative electrode material: The lithium content of the anode material is measured using an inductively coupled plasma optical emission spectrometer (ICP): the anode material is baked at high temperature to remove carbon elements, and the baked product is treated with nitric acid and then hydrofluoric acid, followed by heating to evaporate the acid, and then hydrochloric acid is added and the treatment continues until it is completely dissolved. Finally, the volume is kept constant and then measurement is performed using an inductively coupled plasma optical emission spectrometer. (6) Method for measuring the mass content of carbon material in the negative electrode material: The mass content of the carbon material in the negative electrode material is measured by thermogravimetric analysis. (7)pH measurement method: The pH was measured according to GB / T 24533-2019 standard, where 5g of negative electrode material was dissolved in 45g of water and stirred thoroughly for 30 minutes, after which the measurement was carried out using a Mettler Toledo FE20PH. When measuring, the relevant preparation work such as calibration and operation procedure were carried out according to the instrument manual. (8) Zeta potential measurement method for negative electrode materials: 20 mg of the negative electrode material was weighed and dissolved in deionized water to form a slurry with a pH of 10.5 to 12. The zeta potential of the slurry was measured using a DLS (Digital Light Spectroscopy) and a Malvern Zetasizer Nano ZS90. In this application, the total number of zeta potentials in a certain differential region is considered to be the intensity. (9) Electrochemical performance measurement: Button batteries were manufactured according to the method specified in Beiterui's work instruction BTRTC / ZY / 01-020, "Button Battery Method Work Instruction." A gum solution containing 5% solids was prepared using PAA as a binder. The negative electrode active material and conductive agent were added in a mass ratio of 75:15:10 (negative electrode active material:conductive agent (SP):binder (PAA)). The mixture was uniformly dispersed using a high-speed disperser to form a negative electrode slurry. The slurry was then uniformly coated on a 10 μm-thick copper foil, dried, roll-pressed, punched, and further dried to obtain the negative electrode. The positive electrode was a lithium sheet, and the button battery was assembled in the following order: housing, gasket, nickel sheet, lithium sheet, separator, negative electrode, and housing. Battery performance was measured according to the method specified in GB / T 24533-2019. Battery performance was measured using a battery measurement system from Wuhan Land Electronics Co., Ltd., China. The negative electrode materials prepared in Examples 1 to 8 and Comparative Examples 1 and 2 were assembled into button-type batteries for measurement. Here, a metal lithium sheet was used as the counter electrode, a PP-PE-PP composite membrane with a diameter of 19.2 mm was used as the separator, the composition ratio of the electrolyte was EC / EMC / DMC=1:1:1, and the lithium salt (LiPF6) concentration was 1.05 mol / L. Measurement of specific capacity of negative electrode material: Using a button-type battery charge / discharge device, charge to 10 mV at a constant current of 0.1 C, then charge to 5 mV at a constant current of 0.02 C, and discharge to 1.5 V at a constant current of 0.1 C. 50-cycle measurement of half-cell: Using a button-type battery charge / discharge device, in the first cycle, discharge to 0.01V at 0.1C, gradually decrease discharge at 0.01C to 0.01V, discharge to 0.005V at 0.01C, and charge to 1.5V at 0.1C; in the second cycle, discharge to 0.01V at 0.2C, gradually decrease discharge at 0.02C to 0.01V, discharge to 0.005V at 0.02C, and charge to 1.5V at 0.2C; in the third cycle, discharge to 0.01V at 0.5C. Discharge to 0.01V, then gradually decrease discharge at 0.05C increments, discharge to 0.005V at 0.05C, and charge to 1.5V at 0.5C; from the 4th to 50th cycles, discharge to 0.01V at 1C, gradually decrease discharge at 0.1C increments, discharge to 0.01V at 0.1C increments, and charge to 1.5V at 1C; at the 51st cycle, discharge to 0.01V at 0.1C, gradually decrease discharge at 0.01C increments, and discharge to 0.01V at 0.01C increments. Rate measurement for full battery performance: The negative electrode material and graphite were mixed to achieve a standard capacity of 450 mAh / g. The material rate performance was measured at room temperature (25°C). The battery was charged and discharged at 0.5C (2.75 to 4.2V) to obtain the discharge capacity. The battery was then charged at 1.0C / 0.5C, discharged at 2.0C / 0.5C, and discharged at 3.0C / 0.5C to obtain the discharge capacity for each cycle. The discharge capacity for each cycle was then divided by the discharge capacity for the 0.5C / 0.5C cycle to obtain the rate charge capacity ratio.

[0151] [Table 1]

[0152] As shown in Table 1, the anode materials prepared in Examples 1 to 8 have a coating layer on the surface of the silicon-based core. The coating layer effectively shields the silicon-based core from exposure to the electrolyte, reducing the loss of active silicon and active lithium in the silicon-based core and improving the cycle performance of the anode material. Zeta potential measurements of the anode material revealed that the characteristic peak intensities I1, I2, and I3 satisfied the relationships 0≦I2 / I1≦2.0 and 0≦I3 / I1≦1.0. The surface of the anode material has multiple different surface combinations (i.e., the surface of the anode material is differentiated and diverse). The anode material exhibits good interfacial reaction, establishing a fast mass and charge transfer interface between the anode material and the electrolyte, improving the material charge conduction efficiency and the rate performance of the anode material. Controlling the solid-liquid reaction between the surface of the anode material and the electrolyte forms a stable SEI interface, reducing electrolyte decomposition, suppressing cycle swelling, and improving the cycle performance of the anode material.

[0153] The negative electrode material prepared in Comparative Example 1 did not undergo a coating treatment on the negative electrode active material, resulting in a significant loss of negative electrode active material during cycling, significantly reducing the cycle performance of the negative electrode material. The ratio of I2 / I1 to I3 / I1 was significantly increased, and the surface of the negative electrode material no longer had multiple different surface combinations. During the electrochemical reaction, the unified surface of the negative electrode material made it difficult to control the electrolyte decomposition reaction, resulting in excessive electrolyte decomposition and accumulation, causing electrode piece expansion, significantly increasing the electrode piece expansion rate, and significantly reducing the cycle performance of the negative electrode material. In addition, excessive electrolyte decomposition was unfavorable to the rapid transport of lithium ions, lengthening the lithium ion transport path and reducing the lithium ion transport efficiency, significantly reducing the rate performance of the negative electrode material.

[0154] The anode material prepared in Comparative Example 2 did not undergo surface modification or doping of the coating layer by adding a solid and / or liquid coating agent, resulting in a large I2 / I1 and I3 / I1 ratio in the anode material, which reduced the rationality of the charge ion distribution on the surface of the anode material, and the surface of the anode material became uniform rather than diverse. The uniform surface composition of the anode material made it difficult to establish high-speed ion electron transport paths, reducing the ion electron transport paths in the anode material and reducing ion transport efficiency, thereby reducing the conductivity of the anode material and reducing the rate performance of the anode material. In addition, the uniform surface made it difficult to control the decomposition reaction of the electrolyte during the electrochemical reaction, which led to excessive decomposition of the electrolyte and causing expansion of the electrode pieces, resulting in reduced cycle performance of the anode material.

[0155] The above are only preferred embodiments of the present application, and do not limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application should be included within the protection scope of the present application.

Claims

1. A negative electrode material comprising a silicon-based core and a coating layer located on at least a portion of the silicon-based core, the silicon-based core contains silicon oxide and lithium silicate, and the coating layer contains a carbon material; 20 mg of the negative electrode material was added to 10 ml of deionized water to form a slurry, and the zeta potential of the slurry was measured using a nanoparticle size and zeta potential analyzer. In the zeta potential measurement distribution diagram of the slurry, the maximum intensity of the first characteristic peak within the zeta potential range of -50 mV to -40 mV of the slurry was determined as I. 1 The maximum intensity of the second characteristic peak in the zeta potential range of −65 mV to −50 mV is defined as I 2 The maximum intensity of the third characteristic peak within the zeta potential range of −35 mV to −25 mV is defined as I 3 When I 1 , I 2 and I 3 is 0≦I 2 / I 1 ≦2.0 and 0≦I 3 / I 1 1.0≦1.0

2. The negative electrode material according to claim 1 , wherein the carbon material comprises at least one of graphite, amorphous carbon, diamond-like carbon, carbon fiber, and carbide.

3. The negative electrode material according to claim 1 , wherein the coating layer further comprises at least one of a nitride, a metal oxide, a phosphate, and a silicate.

4. The negative electrode material according to claim 3, which satisfies at least one of the following characteristics (1) to (2): (1) The nitride includes at least one of silicon nitride, pyrrole, and pyridine; (2) The metal oxide includes at least one of titanium oxide, aluminum oxide, magnesium oxide, lithium oxide, zirconium oxide, cobalt oxide, and vanadium oxide.

5. The negative electrode material according to claim 3, which satisfies at least one of the following characteristics (1) to (2): (1) The phosphate salt includes at least one of lithium phosphate, aluminum phosphate, lithium aluminum phosphate, lithium titanium aluminum phosphate, magnesium phosphate, lithium magnesium phosphate, calcium phosphate, lithium calcium phosphate, lithium dihydrogen phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and triammonium phosphate; (2) The silicate includes at least one of lithium silicate, magnesium silicate, aluminum silicate, magnesium aluminum silicate, lithium magnesium silicate, calcium silicate, magnesium calcium silicate, lithium calcium silicate, and lithium aluminum silicate.

6. 2. The negative electrode material according to claim 1, wherein at least a portion of the lithium silicate is located on the surface of the silicate, and the lithium silicate located on the surface of the silicate is distributed in a sparse manner.

7. 2. The negative electrode material according to claim 1, wherein the mass content of the carbon material is 0.5% to 10% when the mass of the negative electrode material is 100%.

8. 2. The negative electrode material according to claim 1, wherein the mass content of lithium in the negative electrode material is 2% to 15% when the mass of the negative electrode material is 100%.

9. The mass content of lithium in the silicon-based core is 10 3 ppm to 10 5 2. The negative electrode material of claim 1, wherein the content of the metal ions in the negative electrode is 0.1 ppm.

10. The general formula of the lithium silicate is Li 2 O-nSiO 2 The negative electrode material according to claim 1 , wherein n is 0<n≦4.

11. 2. The negative electrode material according to claim 1, wherein the pH value is 10.0 to 12.

3.

12. A method for producing an anode material, comprising the steps of: using a coating agent and a coating gas source containing a gaseous carbon source in combination to form a coating layer by vapor deposition on the surface of a silicon-based core to obtain an anode material; wherein the coating agent is a non-vapor-phase coating agent having a benzene ring structure; and the silicon-based core contains silicon oxide and lithium silicate.

13. The manufacturing method according to claim 12 , further comprising adding an auxiliary carrier gas during the vapor deposition process.

14. The manufacturing method according to claim 13, which satisfies at least one of the following characteristics (1) to (3): (1) The auxiliary carrier gas is H 2 , CO 2 , N.H. 3 and Ar; (2) The flow rate of the auxiliary carrier gas is 100 mL / min to 8000 mL / min; (3) The flow rate ratio of the gaseous carbon source to the auxiliary carrier gas is (3 to 9.5):(0.5 to 7).

15. A lithium ion battery comprising the negative electrode material according to any one of claims 1 to 11, or the negative electrode material produced by the method for producing the negative electrode material according to any one of claims 12 to 14.

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