Negative electrode material, manufacturing method thereof, and secondary battery

Abstract

The present application relates to the technical field of batteries, and in particular to a negative electrode material containing a silicon-based active material and a matrix material, a method for producing the same, and a secondary battery. [Solution] The negative electrode material contains hydrogen, halogen, nitrogen, and sulfur, and the mass content of hydrogen is m H The mass content of the halogen element is m X The mass content of sulfur element is m S The mass content of nitrogen is m N When this is the case, 0.02≦m X / m H ≦5.00, 0.02≦m N / m H ≦20.00, 0.05≦m S / m H The technical solution of the present application adjusts the contents of hydrogen, nitrogen, sulfur and halogen elements within an appropriate range, thereby effectively suppressing the volume expansion of the negative electrode material and improving the capacity, initial coulombic efficiency, powder conductivity, cycle performance and rate performance of the negative electrode material.

Description

[Technical Field]

[0001] The present application relates to the technical field of batteries, and in particular to a negative electrode material and a method for producing the same, and a secondary battery. [Background technology]

[0002] In recent years, lithium-ion batteries have been widely used in electric vehicles and consumer electronics due to their advantages, such as high energy density, high output power, long cycle life, and minimal environmental pollution. The anode material is one of the most important components of a lithium-ion battery, and its structure and performance directly affect the electrochemical behavior of the battery. Among these, silicon-based anode materials are one of the most important anode materials for high-energy-density lithium-ion batteries. However, conventional silicon-based anode materials suffer from problems such as large volume expansion and poor rate performance, limiting their widespread application in lithium batteries.

[0003] To improve the volume expansion of silicon-based materials, silicon-based materials are generally combined with carbon materials. However, a simple carbon coating layer has difficulty effectively blocking interfacial side reactions between the electrolyte and the anode material. In addition, a large amount of gas is generated during the process of producing anode slurry using silicon-based materials. The volume expansion of the material during charge / discharge cycling also affects the performance of the anode material, such as its cycle life.

[0004] Therefore, improving the contact interface between the negative electrode material and the electrolyte and mitigating the volume expansion of the negative electrode material remain technical challenges to be solved. Summary of the Invention [Problem to be solved by the invention]

[0005] The present application provides an anode material that is advantageous in improving the stability of the solid-liquid contact interface of the anode material, is advantageous in mitigating volume expansion of the anode material, and improves initial efficiency and cycle performance, a method for producing the same, and a secondary battery. [Means for solving the problem]

[0006] In a first aspect, the present application provides the following negative electrode material: A negative electrode material comprising a silicon-based active material and a matrix material, the negative electrode material comprising hydrogen, halogen, nitrogen and sulfur, and a mass content of hydrogen of m H The mass content of the halogen element is m X The mass content of sulfur element is m S The mass content of nitrogen is m N When this is done, 0.02≦m X / m H ≦5.00, 0.02≦m N / m H ≦20.00, and 0.05≦m S / m H Meets ≦5.00.

[0007] In some embodiments, the matrix material is formed on at least a portion of the surface of the silicon-based active material.

[0008] In some embodiments, the silicon-based active material is formed on the surface of the matrix material.

[0009] In some embodiments, the silicon-based active material and the matrix material are dispersed within one another.

[0010] In some embodiments, the negative electrode material comprises pores.

[0011] In some embodiments, the pore volume distribution curve of the negative electrode material has characteristic peaks of pore volume within the pore diameter ranges of 240 Å to 280 Å, 290 Å to 320 Å, 340 Å to 390 Å, and 410 Å to 460 Å.

[0012] In some embodiments, the negative electrode material has a concentration of 50 mg / kg or less. X ≦1500 mg / kg.

[0013] In some embodiments, the negative electrode material has a concentration of 100 mg / kg or less. N ≦4000mg / kg.

[0014] In some embodiments, the negative electrode material has a concentration of 10 mg / kg or less. S ≦200 mg / kg.

[0015] In some embodiments, the silicon-based active material comprises at least one of elemental silicon, silicon oxide, silicon alloy, and silicate.

[0016] In some embodiments, the silicon-based active material comprises silicon oxide, which has the general formula SiO x (0 <x≦2)である。

[0017] In some embodiments, the silicon-based active material comprises a doping metal M, which is at least one selected from Li, Mg, Al, Fe, La, Zn, Ti, Cu, and Mn.

[0018] In some embodiments, the silicon-based active material comprises a doping metal M, and the mass content of the metal M in the negative electrode material is greater than 0 wt % and less than or equal to 15 wt %.

[0019] In some embodiments, the matrix material comprises a carbon material or a mixture of a carbon material and an inorganic oxide.

[0020] In some embodiments, the matrix material comprises a carbon material including at least one of graphite, graphene, amorphous carbon, diamond-like carbon, carbon nanotubes, and carbon fibers.

[0021] In some embodiments, the matrix material includes a carbon material, and the carbon material is formed on at least a portion of the surface of the silicon-based active material to form a carbon layer having a thickness of 20 nm to 1000 nm.

[0022] In some embodiments, the mass content of carbon element in the negative electrode material is 0.5 wt % to 15 wt %, based on the mass of the negative electrode material.

[0023] In some embodiments, the median diameter of the negative electrode material is 2.0 μm to 12.0 μm.

[0024] In some embodiments, the specific surface area of ​​the negative electrode material is 0.50 m 2 / g~10.00m 2 / g.

[0025] In some embodiments, the tap density of the negative electrode material is 0.75 g / cm 3 ~1.35g / cm 3 is.

[0026] In some embodiments, the powder conductivity of the negative electrode material under a pressure of 20 kN is 0.01 S / cm to 100.00 S / cm.

[0027] In some embodiments, the mass content of water in the negative electrode material is 0.01 wt% to 0.80 wt%.

[0028] In some embodiments, the negative electrode material has a pH of 6.00 to 12.00.

[0029] In a second aspect, the present embodiment further provides the following method for producing a negative electrode material. preparing a precursor comprising a silicon-based active material and a matrix material; and surface-modifying the precursor by plasma-enhanced chemical vapor deposition in a modified gas-phase source environment to obtain an anode material, the modified gas-phase source containing hydrogen, sulfur, nitrogen, and halogen elements, and the mass content of hydrogen in the anode material is m H The mass content of the halogen element is m X The mass content of sulfur element is mS The mass content of nitrogen is m N When this is the case, 0.02≦m X / m H ≦5.00, 0.02≦m N / m H ≦20.00, 0.05≦m S / m H ≦5.00, a method for producing a negative electrode material.

[0030] In a third aspect, embodiments of the present application further provide a secondary battery including the negative electrode material described above or a negative electrode material produced by the method described above. [Effects of the Invention]

[0031] Compared with the prior art, the technical solution of the present application has at least the following technical advantages: In the present invention, the relationship between the content of hydrogen, nitrogen, sulfur, and halogen elements is explored, and the mass ratio of hydrogen, nitrogen, sulfur, and halogen elements in the negative electrode material is adjusted within an appropriate range to comprehensively improve the powder conductivity, initial efficiency, and cycle performance of the material. The present invention also includes appropriate amounts of halogen, N, and S. The appropriate amount of halogen helps form a more stable solid electrolyte interlayer (SEI) when the electrolyte contacts the negative electrode material, strengthening the bonding strength between the negative electrode material and the solid electrolyte interlayer, which is beneficial for maintaining the stability of the solid-liquid contact interface on the surface of the negative electrode material during cyclic charging and discharging and better suppressing the expansion of the negative electrode material. The nitrogen and sulfur elements further improve the conductivity of the negative electrode material powder, further improving the rate performance of the negative electrode material. When the relationship between the hydrogen, nitrogen, sulfur, and halogen contents in the negative electrode material satisfies the above ratio relationship, the permeability of the electrolyte into the negative electrode material can be improved, solid-liquid control can be achieved during the slurry preparation process of the negative electrode material, the dispersibility of the slurry can be improved, settling or aggregation of the slurry can be reduced, gas generation during the slurry preparation process can be suppressed, and the stability of the slurry can be maintained. Therefore, the negative electrode material according to the present application can have advantages such as high initial efficiency, high powder conductivity, high cycle stability, and low volume expansion coefficient.

[0032] The method for producing a negative electrode material provided herein involves surface-modifying a precursor containing a silicon-based active material and a carbon material by plasma-enhanced chemical vapor deposition in a modified gas source environment, thereby efficiently and uniformly doping multiple elements and achieving high deposition efficiency and controllability. After the surface modification, the carbon material on the surface of the silicon-based active material can bond with hydrogen atoms to form carbon-hydrogen bonds. The appropriate carbon-hydrogen bond saturation contributes to adjusting the hydrophilicity of the material, thereby adjusting the hydrophilicity of the carbon material and the penetration of the electrolyte into the negative electrode material. This smooths the lithium ion conductive interface between the negative electrode material and the electrolyte, improving the mass transfer / charge transfer efficiency of the negative electrode material, and further improving the low-temperature performance and powder conductivity of the negative electrode material. The incorporation of appropriate amounts of halogens, nitrogen, and sulfur can play the following roles: Adjusting the carbon-hydrogen bond saturation: Halogens and hydrogen compete for saturation, and the presence of halogens occupies hydrogen sites, thereby adjusting the carbon-hydrogen bond saturation. Nitrogen and sulfur combine with hydrogen to form local functional groups, such as amino groups, which can also adjust the carbon-hydrogen bond saturation. Meanwhile, halogens can contribute to the formation of a more stable solid electrolyte interlayer (SEI) upon contact with the electrolyte and anode material, strengthening the bond between the anode material and the SEI. This helps maintain the stability of the solid-liquid contact interface on the anode material surface during cyclic charging and discharging and better suppresses the expansion of the anode material. Nitrogen and sulfur also improve the electrical conductivity of the anode material powder, further improving the rate performance of the anode material. Therefore, by modifying the surface of the negative electrode material using a modifying gas source, the volume expansion of the negative electrode material can be suppressed, and the electrochemical performance of the negative electrode material, such as initial efficiency, powder conductivity, and cycle performance, can be comprehensively improved. [Brief explanation of the drawings]

[0033] The present application will now be further described with reference to the figures and examples. [Figure 1] FIG. 1 is an FTIR diagram of a negative electrode material according to an example of the present application. [Figure 2] 1 is a flowchart of a method for manufacturing a negative electrode material according to an embodiment of the present application. [Figure 3] FIG. 2 is a schematic diagram of a discharged state of a secondary battery according to an embodiment of the present invention. [Figure 4] FIG. 2 is a schematic diagram of the pore volume distribution of the negative electrode material according to Example 1 of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0034] In order to better understand the technical solution of the present application, the following describes in detail the embodiments of the present application with reference to the accompanying drawings.

[0035] It should be clear that the described embodiments are only some of the embodiments of the present application, but not all of the embodiments, and all other embodiments that a person skilled in the art can obtain based on the embodiments of the present application without any inventive effort fall within the scope of protection of the present application.

[0036] The terms used in the examples of this application are used only to describe particular examples and are not intended to limit the application. As used in the examples and claims of this application, the singular forms "a," "the," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0037] It should be understood that the term "and / or" used herein is only for describing the relation between related objects, and indicates that three kinds of relations can exist. For example, A and / or B can indicate three kinds of situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the text generally indicates that the related objects before and after it are in an "or" relationship.

[0038] Silicon-based anode materials are one of the most important materials for high-energy-density lithium-ion batteries. However, conventional silicon-based anode materials have problems such as large expansion and poor rate performance, limiting their widespread application in lithium-ion batteries.

[0039] In previous related research, the G and D peaks of the carbon layer structure on the surface of silicon-based anode materials have often been studied to improve the surface physicochemical properties of silicon-based anode materials, but it has been difficult to comprehensively improve the volume expansion and electrochemical performance of silicon-based anode materials.

[0040] To solve the above problems, in a first aspect, the present application provides a negative electrode material including a silicon-based active material and a matrix material. The silicon-based active material may be formed on at least a portion of the surface of the matrix material, the matrix material may be located on the surface of the silicon-based active material, or both the silicon-based active material and the matrix material may be dispersed in each other. In some embodiments, the matrix material may include a carbon material or a mixture of a carbon material and an inorganic oxide.

[0041] The negative electrode material contains hydrogen, halogen, nitrogen, and sulfur, and the mass content of hydrogen is m H and the mass content of the halogen element is m X (If the negative electrode material contains multiple halogen elements, m X is the total mass content of multiple halogen elements), and the mass content of sulfur element is m S and the mass content of nitrogen is m N If m X / m H ≦5.00, 0.02≦m N / m H ≦20.00, 0.05≦m S / m H In the negative electrode material, hydrogen and halogen elements are mainly used as the terminal elements of the matrix material to modify the interface and structure of the negative electrode material, while nitrogen and sulfur are mainly used as doping elements in the matrix material, which is beneficial to improving the electrochemical performance of the negative electrode material, such as rate performance, powder conductivity, and pre-cycle stability.

[0042] In some embodiments, m X / m HThe value of may be 0.02, 0.05, 0.1, 0.5, 0.8, 1, 2, 3, 4, or 5, etc., and of course, may be other values ​​within the above range and are not limited thereto. The presence of an appropriate content of halogen contributes to improving the conductivity of the negative electrode material and can be involved in the formation of a solid electrolyte membrane (SEI membrane) on the surface of the negative electrode material, improving the stability of the SEI membrane, further suppressing the expansion of the negative electrode material, and improving the cycle performance of the negative electrode material. Controlling the mass ratio of halogen to hydrogen within the above range can improve the capacity, initial coulombic efficiency, and rate performance of the negative electrode material. However, excessive halogen not only causes excessive embrittlement within the matrix layer but also increases the specific surface area of ​​the negative electrode material and reduces the electrochemical performance of the negative electrode material, such as the capacity, initial coulombic efficiency, and rate performance.

[0043] In some embodiments, m N / m H The value of m may be 0.02, 0.05, 0.1, 0.5, 0.8, 1, 2, 4, 8, 12, 16, or 20, etc., and of course may be other values ​​within the above range, and is not limited herein. S / m H The value of may be 0.05, 0.1, 0.5, 0.8, 1, 1, 2, 3, 4, or 5, etc., and of course, other values ​​within the above range are also possible and are not limited thereto. Rational adjustment of the ratio of nitrogen and sulfur to hydrogen improves the binding ability of the negative electrode material with lithium ions, favors desolvation of lithium ions at the interface, and allows lithium ions to more easily enter the interior of the negative electrode material, further improving the rate performance of the negative electrode material. Furthermore, the presence of nitrogen and sulfur significantly improves the powder conductivity of the negative electrode material, favoring the improvement of the early cycle stability of the negative electrode material.

[0044] In some embodiments, chemical bonds such as CH, OH, C—Cl, CF, C—Br, CN, ON, CS, and SO are formed after doping with hydrogen, halogen, nitrogen, and sulfur. The relationship between the hydrogen, nitrogen, sulfur, and halogen contents of the present negative electrode material is explored, and the mass ratio of hydrogen to nitrogen, sulfur, and halogen in the negative electrode material is adjusted within an appropriate range to comprehensively improve the powder conductivity, initial efficiency, and cycling performance of the material. The present negative electrode material contains carbon-hydrogen bonds formed by the bonding of hydrogen and carbon atoms (as shown in FIG. 1 ). Controlling the saturation of the carbon-hydrogen bonds contributes to adjusting the hydrophilicity of the material, improving the electrolyte's penetration into the material, smoothing the lithium ion conductive interface between the negative electrode material and the electrolyte, and improving the mass / charge transfer efficiency of the negative electrode material. This also improves the low-temperature performance and powder conductivity of the negative electrode material. In this application, the anode material further contains an appropriate amount of halogen, N, and S, which adjust the carbon-hydrogen bond saturation. Halogen and H have a competitive saturation relationship, and the presence of halogen occupies the H site, thereby adjusting the carbon-hydrogen bond saturation. Nitrogen and sulfur can bond with hydrogen to form local functional groups such as amino groups, which also adjust the carbon-hydrogen bond saturation. Meanwhile, halogen can also participate in the formation of a more stable solid electrolyte interlayer (SEI) when the electrolyte contacts the anode material, strengthening the bond between the anode material and the solid electrolyte interlayer. This is beneficial for maintaining the stability of the solid-liquid contact interface on the surface of the anode material during cyclic charging and discharging and better suppressing the expansion of the anode material. Nitrogen and sulfur can also further improve the conductivity of the anode material powder, further improving the rate performance of the anode material.When the relationship between the hydrogen, nitrogen, sulfur, and halogen contents in the negative electrode material satisfies the above ratio relationship of the present application, the permeability of the electrolyte into the negative electrode material can be improved, solid-liquid control can be achieved during the slurry preparation process of the negative electrode material, the dispersibility of the slurry can be improved, settling or aggregation of the slurry can be reduced, gas generation during the slurry preparation process can be suppressed, and the stability of the slurry can be maintained. Therefore, the negative electrode material of the present application can combine advantages such as high initial efficiency, high powder conductivity, high cycle stability, and low volume expansion coefficient. Furthermore, the applicant's research, exploration, and data verification have shown that the technical problem to be solved by the present application can be solved as long as the above relationship is satisfied, regardless of the specific form of the halogen, nitrogen, and sulfur elements.

[0045] In some embodiments, the negative electrode material has a concentration of 50 mg / kg or less. X The mass of the halogen element contained in 1 kg of the negative electrode material may be 50 mg, 150 mg, 300 mg, 600 mg, 900 mg, 1200 mg, or 1500 mg, etc., and may naturally be other values ​​within the above range, and is not limited thereto. By controlling the content of the halogen element in the negative electrode material, the initial capacity efficiency, rate performance, and cycle performance of the negative electrode material can be further improved, and expansion of the negative electrode material can be further suppressed.

[0046] In some embodiments, the negative electrode material has a concentration of 100 mg / kg or less. N The nitrogen content in the negative electrode material is ≦4000 mg / kg, i.e., the mass of nitrogen element contained in 1 kg of the negative electrode material may be 100 mg, 500 mg, 1000 mg, 2000 mg, 4000 mg, etc., and may of course be other values ​​within the above range, and is not limited thereto. By controlling the nitrogen content in the negative electrode material, the initial capacity efficiency, rate performance, and cycle performance of the negative electrode material can be further improved, and expansion of the negative electrode material can be further suppressed.

[0047] In some embodiments, the negative electrode material has a concentration of 10 mg / kg or less.S The mass of elemental sulfur contained in 1 kg of the negative electrode material may be 10 mg, 30 mg, 50 mg, 80 mg, 100 mg, 120 mg, 150 mg, 180 mg, or 200 mg, etc., and may naturally be other values ​​within the above range, and is not limited thereto. By controlling the content of elemental sulfur in the negative electrode material, the capacity, initial efficiency, and rate performance of the negative electrode material can be improved.

[0048] In some embodiments, the negative electrode material includes pores. The presence of pores in the negative electrode material can provide a buffer space for the volume expansion of the silicon-based active material, reduce phenomena such as particle crushing and rupture due to the volume expansion, and improve the cycle stability of the negative electrode material.

[0049] In some embodiments, the pore volume distribution curve of the negative electrode material has a characteristic pore volume peak at a pore diameter in the range of 240 Å to 280 Å, 290 Å to 320 Å, 340 Å to 390 Å, or 410 Å to 460 Å. That is, the pore volume distribution curve of the negative electrode material has a characteristic pore volume peak at a pore diameter of 240 Å, 250 Å, 260 Å, 270 Å, 280 Å, or any value therebetween; at a pore diameter of 290 Å, 300 Å, 310 Å, 320 Å, or any value therebetween; at a pore diameter of 340 Å, 350 Å, 360 Å, 370 Å, 380 Å, 390 Å, or any value therebetween; and at a pore diameter of 410 Å, 420 Å, 430 Å, 440 Å, 450 Å, 460 Å, or any value therebetween. Differences in elemental composition and carbon-hydrogen bond saturation in materials both affect the morphology of the material. In the present application, by adjusting the mass content ratio of hydrogen to nitrogen, sulfur, and halogen elements in the negative electrode material within an appropriate range, the local structure grows vertically, forming the above-mentioned unique pore structure, which is advantageous for improving the electrochemical performance, such as the rate performance and cycle stability, of the negative electrode material.

[0050] In some embodiments, the median diameter of the negative electrode material is 2.0 μm to 12.0 μm, specifically, it may be 2.0 μm, 4.0 μm, 6.0 μm, 8.0 μm, 10.0 μm, 12.0 μm, etc., and of course, it may also be other values within the above range, and is not limited here.

[0051] In some embodiments, the silicon-based active material contains at least one of elemental silicon, silicon oxide, silicon alloy, and silicate. That is, the silicon-based active material may be composed of any one of elemental silicon, silicon oxide, silicon alloy, and silicate alone, or may be composed of a mixture of two or more of elemental silicon, silicon oxide, silicon alloy, and silicate.

[0052] In the above embodiment, the general formula of the silicon oxide is SiO x (0 < x ≤ 2), and generally, the silicon oxide is a mixture of multiple types of silicon oxygen compounds, for example, a mixture of silicon dioxide and silicon monoxide.

[0053] In some embodiments, the silicon-based active material further contains a doping metal M which is at least one selected from Li, Mg, Al, Fe, La, Zn, Ti, Cu, and Mn. Specifically, the doping metal M may be present in the silicon alloy or silicate. The silicate may be a monosilicate (containing one type of metal ion) such as lithium silicate, magnesium silicate, aluminum silicate, iron silicate, etc., or may be a disilicate (containing two types of metal ions) such as lithium magnesium silicate, lithium aluminum silicate, lithium zinc silicate, etc., or may be a trisilicate (containing three types of metal ions) such as lithium titanium aluminum silicate, lithium magnesium aluminum silicate, etc., and is not limited thereto. In one specific example, the silicon-based active material contains doping metal Mg and / or doping metal Li.

[0054] In some embodiments, the mass content of the metal M in the negative electrode material is 0 wt% to 15 wt%, but does not include 0 wt%. Specifically, it may be 0.000001 wt%, 1 wt%, 5 wt%, 10 wt%, or 15 wt%, and may naturally be other values ​​within the above range, and is not limited thereto.

[0055] In some embodiments, the mass content ω2 of carbon element in the negative electrode material is 0.5 wt% to 15 wt%, and specifically may be 0.5 wt%, 1 wt%, 5 wt%, 10 wt%, 15 wt%, etc., and may naturally be other values ​​within the above range, and is not limited here.

[0056] In some embodiments, the carbon material comprises at least one of graphite, graphene, amorphous carbon, diamond-like carbon, carbon nanotubes, and carbon fibers.

[0057] In some embodiments, when the carbon material is amorphous carbon, the negative electrode material may include a mixture of nitrogen-doped amorphous carbon, chlorine-doped amorphous carbon, bromine-doped amorphous carbon, iodine-doped amorphous carbon, sulfur-doped amorphous carbon, and the like.

[0058] In some embodiments, the carbon material forms a carbon layer on the surface of the silicon-based active material, and the thickness of the carbon layer ranges from 20 nm to 1000 nm, specifically, may be 20 nm, 100 nm, 200 nm, 400 nm, 800 nm, or 1000 nm, etc., and may of course be other values ​​within the above range, and is not limited thereto.

[0059] In some embodiments, the inorganic oxide comprises a metal oxide such as aluminum (Al), titanium (Ti), vanadium (V), chromium (Cr), niobium (Nb), molybdenum (Mo), yttrium (Y), lanthanum (La), cerium (Ce), lithium (Li), or a polyvalent metal oxide that combines multiple elements.

[0060] In some embodiments, inorganic oxides may be formed with aluminum (Al), titanium (Ti), vanadium (V), chromium (Cr), niobium (Nb), molybdenum (Mo), yttrium (Y), lanthanum (La), cerium (Ce), lithium (Li), and the like, and phosphorus (P), silicon (Si), titanium (Ti), and the like, as mono- or poly-component silicates, phosphates, titanates.

[0061] In some embodiments, the tap density of the negative electrode material is 0.75 g / cm 3 ~1.35g / cm 3 Specifically, 0.75 g / cm 3 , 0.95g / cm 3 , 1.05g / cm 3 , 1.35g / cm 3 or any value therebetween, and it should be understood that the tap density of the negative electrode material is 1.35 g / cm 3 The tap density may be higher, and a higher tap density is advantageous for improving the energy density of the material, but the present application is not particularly limited thereto.

[0062] In some embodiments, the powder conductivity of the negative electrode material under a pressure of 20 kN is 0.01 S / cm to 100.00 S / cm, specifically, 0.01 S / cm, 10.00 S / cm, 40.00 S / cm, 60.00 S / cm, 80.00 S / cm, 100.00 S / cm, or any value therebetween. It should be understood that the powder conductivity of the negative electrode material may be higher than 100.00 S / cm, and a higher powder conductivity is advantageous for improving the electrochemical performance of the material, and the present application is not particularly limited thereto.

[0063] In some embodiments, the specific surface area of ​​the negative electrode material is 0.50 m 2 / g~10.00m 2 / g, specifically, 0.80m 2 / g, 1.00m 2 / g, 1.50m 2 / g, 2.00m 2 / g, 3.00m 2 / g, 4.00m 2 / g, 5.00m 2 / g, 8.00m 2 / g or 10.00m 2 / g, etc., and of course, other values ​​within the above range may also be used, and are not limited thereto. By controlling the specific surface area of ​​the negative electrode material within the above range, it is possible to mitigate the volume expansion of the negative electrode material, which is advantageous for improving the cycle performance of the negative electrode material.

[0064] In some embodiments, the mass content of water in the negative electrode material is 0.01 wt % to 0.80 wt %, for example, specifically, 0.01%, 0.10%, 0.40%, 0.60%, 0.80%, or any value therebetween, and a lower mass content of water in the negative electrode material is advantageous for improving the electrochemical performance of the material, and the present application is not particularly limited thereto.

[0065] In some embodiments, the pH range of the negative electrode material is 6.00 to 12.00, and may be specifically 6.00, 8.00, 9.00, 10.00, 11.00, or 12.00, etc., and may of course be other values ​​within the above range, and is not limited thereto. Preferably, the pH range of the negative electrode material is 7 to 10.

[0066] In a second aspect, the present application further provides a method for manufacturing the negative electrode material, including steps S100 and S200, as shown in FIG. 2 , In step S100, a precursor containing a silicon-based active material and a substrate material is produced. In step S200, the precursor is surface-modified by plasma-enhanced chemical vapor deposition in a modified gas source environment to obtain an anode material, the modified gas source including hydrogen, sulfur, nitrogen, and halogen elements, and the mass content of hydrogen in the anode material is m H The mass content of the halogen element is m X The mass content of sulfur element is m S The mass content of nitrogen is m NWhen this is the case, 0.02≦m X / m H ≦5.00, 0.02≦m N / m H ≦20.00, 0.05≦m S / m H ≦5.00. The method for producing a negative electrode material provided herein involves surface-modifying a precursor containing a silicon-based active material and a substrate material by plasma-enhanced chemical vapor deposition in a modified gas source environment, thereby efficiently and uniformly doping multiple elements and achieving high deposition efficiency and controllability. After the surface modification, the substrate material on the surface of the silicon-based active material can bond with hydrogen atoms to form carbon-hydrogen bonds. The appropriate carbon-hydrogen bond saturation contributes to adjusting the hydrophilicity of the material, thereby adjusting the hydrophilicity of the substrate material and the penetration of the electrolyte into the negative electrode material, resulting in a smoother lithium ion conductive interface between the negative electrode material and the electrolyte, improving the mass transfer / charge transfer efficiency of the negative electrode material, and further improving the low-temperature performance and powder conductivity of the negative electrode material. The incorporation of appropriate amounts of halogens, nitrogen, and sulfur can play the following roles: Adjusting the carbon-hydrogen bond saturation: Halogens and hydrogen compete for saturation. The presence of halogens occupies hydrogen sites, thereby adjusting the carbon-hydrogen bond saturation. Nitrogen and sulfur can also bond with hydrogen to form local functional groups, such as amino groups, which can adjust the carbon-hydrogen bond saturation. The halogens also contribute to the formation of a more stable solid electrolyte interlayer (SEI) upon contact with the electrolyte and anode material, strengthening the bond between the anode material and the SEI. This helps maintain the stability of the solid-liquid interface on the anode material surface during cycle charging and discharging and better suppresses the expansion of the anode material. The nitrogen and sulfur elements also further improve the electrical conductivity of the anode material powder, further enhancing the rate performance of the anode material. Therefore, by surface-modifying the surface of the negative electrode material using a modifying gas source, the volume expansion of the negative electrode material can be suppressed, and the electrochemical performance of the negative electrode material, such as initial efficiency, powder conductivity, and cycle performance, can be comprehensively improved.

[0067] The production method of the present invention will be specifically described below based on examples. In step S100, a precursor containing a silicon-based active material and a substrate material is produced.

[0068] In some embodiments, a specific step of preparing a precursor includes coating at least a portion of the surface of a silicon-based active material with a substrate material.

[0069] In some embodiments, the specific steps for preparing the precursor include a step of solid-phase coating the silicon-based active material and the substrate material.

[0070] In some embodiments, the matrix material comprises a carbon material or a mixture of a carbon material and an inorganic oxide, hi some embodiments, the carbon material comprises at least one of graphite, graphene, amorphous carbon, diamond-like carbon, carbon nanotubes, and carbon fibers.

[0071] In some embodiments, the inorganic oxide comprises a metal oxide such as aluminum (Al), titanium (Ti), vanadium (V), chromium (Cr), niobium (Nb), molybdenum (Mo), yttrium (Y), lanthanum (La), cerium (Ce), lithium (Li), or a multi-component metal oxide that combines multiple elements.

[0072] In some embodiments, inorganic oxides may be formed with aluminum (Al), titanium (Ti), vanadium (V), chromium (Cr), niobium (Nb), molybdenum (Mo), yttrium (Y), lanthanum (La), cerium (Ce), lithium (Li), and the like, and phosphorus (P), silicon (Si), titanium (Ti), and the like, as mono- or poly-component silicates, phosphates, titanates.

[0073] In some embodiments, the step of solid-state coating the silicon-based active material and the carbon material includes mixing the silicon-based material and a solid carbon source (e.g., pitch, etc.) in a ball mill, followed by high-temperature treatment to achieve coating of the carbon material on the silicon-based active material.

[0074] In some embodiments, the specific steps of preparing the precursor include vapor-phase carbon coating of a silicon-based active material in a vapor-phase carbon source.

[0075] In some embodiments, the gas phase carbon source comprises at least one of methane, ethane, ethylene, propane, and propylene.

[0076] In some embodiments, the temperature of the vapor-phase carbon coating is 600-1000°C, and the incubation time is 1 hour-48 hours. Those skilled in the art can adjust the specific reaction time depending on the type, flow rate, deposition temperature, and target carbon amount of the carbon source gas.

[0077] In some embodiments, the mass content of the carbon material in the precursor ranges from 1 wt% to 10 wt%, preferably from 2 wt% to 7 wt%.

[0078] In some embodiments, the silicon-based active material comprises at least one of elemental silicon, silicon oxide, silicon alloy, and silicate.

[0079] In some embodiments, the silicon based active material comprises a doping metal M, which is at least one selected from Li, Mg, Al, Fe, La, Zn, Ti, Cu, and Mn.

[0080] In some embodiments, when a silicon-based active material is vapor-phase carbon-coated, the specific steps for preparing the precursor further include grinding and sieving the coated product.

[0081] In some embodiments, after step S100, the method further includes purifying the precursor to remove impurities in the precursor.

[0082] In some embodiments, specific steps of the purification process include washing and drying the precursor.

[0083] In some embodiments, the cleaning process may include rinsing, immersion, and centrifugation. Specifically, the precursor is first rinsed with deionized water to remove impurities from the surface of the precursor, and then immersed and centrifuged to remove impurities inside or in the pores of the precursor, which contributes to ensuring consistent reaction rates of hydrogen attachment (sulfur attachment, nitrogen attachment, or halogen attachment) between precursor particles and reduces the difference in hydrogen content (nitrogen content, sulfur content, and halogen content) between different particles.

[0084] In some embodiments, from the standpoint of cost and rinsing effectiveness, the rinse is performed with deionized water, although other suitable cleaning agents may be selected for rinsing.

[0085] In some embodiments, from the viewpoint of cost and immersion effect, the silicon-based active material coated with a carbon material is immersed in deionized water. Naturally, other suitable immersion liquids may be selected to perform the immersion treatment on the silicon-based active material coated with a carbon material. In such embodiments, the mass ratio of the silicon-based active material coated with a carbon material to the immersion liquid during the immersion process is preferably (0.5 to 1.5):(1.5 to 2.5). If the ratio is too large, the immersion effect will not be ideal, and if the ratio is too small, the immersion liquid (deionized water) will be wasted.

[0086] In some embodiments, the drying is performed under vacuum to keep the drying temperature as low as possible, and the use of low-temperature vacuum drying can effectively control the degree of surface oxidation of the material, which is advantageous for improving the reaction efficiency of hydrogen attachment (sulfur attachment, nitrogen attachment, or halogen attachment) of the precursor.

[0087] In some embodiments, the centrifugation time is 30 to 360 minutes, and may be, specifically, 30, 90, 150, 200, 250, 300, or 360 minutes, or may be any other value within the above range, and is not limited thereto.

[0088] In some embodiments, the drying temperature is 45°C to 80°C, specifically 45°C, 50°C, 60°C, 70°C, or 80°C, and may of course be other values ​​within the above range and is not limited thereto. The drying time is 3 hours to 48 hours, specifically 3 hours, 10 hours, 20 hours, 30 hours, 40 hours, or 48 hours, and may of course be other values ​​within the above range and is not limited thereto.

[0089] In step S200, the precursor is surface-modified by plasma-enhanced chemical vapor deposition in a modified gas source environment to obtain an anode material, the modified gas source including hydrogen, sulfur, nitrogen, and halogen elements, the anode material including hydrogen, halogen, nitrogen, and sulfur, and the mass content of hydrogen is m H The mass content of the halogen element is m X The mass content of sulfur element is m S The mass content of nitrogen is m N When this is the case, 0.02≦m X / m H ≦5.00, 0.02≦m N / m H ≦20.00, 0.05≦m S / m H Meets ≦5.00.

[0090] In some embodiments, the electrical conductivity of the precursor powder under a pressure of 20 KN is 0.001 S / cm to 0.1 S / cm, specifically 0.001 S / cm, 0.005 S / cm, 0.01 S / cm, 0.05 S / cm, or 0.1 S / cm, and may naturally be other values ​​within the above range and is not limited thereto. The electrical conductivity of the negative electrode material powder under a pressure of 20 KN is 0.1 S / cm to 100.0 S / cm, specifically 0.1 S / cm, 1 S / cm, 10 S / cm, 50 S / cm, or 100 S / cm, and may naturally be other values ​​within the above range and is not limited thereto.

[0091] In some embodiments, the pore volume distribution curve of the negative electrode material has a characteristic pore volume peak at a pore diameter in the range of 240 Å to 280 Å, 290 Å to 320 Å, 340 Å to 390 Å, or 410 Å to 460 Å. That is, the pore volume distribution curve of the negative electrode material has a characteristic pore volume peak at a pore diameter of 240 Å, 250 Å, 260 Å, 270 Å, 280 Å, or any value therebetween; at a pore diameter of 290 Å, 300 Å, 310 Å, 320 Å, or any value therebetween; at a pore diameter of 340 Å, 350 Å, 360 Å, 370 Å, 380 Å, 390 Å, or any value therebetween; and at a pore diameter of 410 Å, 420 Å, 430 Å, 440 Å, 450 Å, 460 Å, or any value therebetween. The composition of the modifying gas source during the deposition process, and the deposition conditions such as the deposition method and deposition rate all affect the morphology of the material. In the present application, by adjusting the mass content ratio of hydrogen to nitrogen, sulfur, and halogen elements in the modifying gas source within an appropriate range, and by controlling the deposition conditions such as the deposition rate within an appropriate range, the surface layer of the material is based on carbon elements, and the local structure grows vertically, forming the above-mentioned unique mesoporous structure.

[0092] In some embodiments, the specific steps of S200 include evacuation, placing the precursor under a modified gas source, and plasma-enhanced chemical vapor deposition of the precursor under bias voltage conditions. By adjusting the modified gas source with different gas compositions and intervening in the bias voltage, the deposition efficiency of the hydrogen, halogen, nitrogen, and sulfur element precursors can be effectively controlled, thereby controlling the morphology, powder conductivity, rate performance, cycle performance, initial capacity efficiency, low-temperature performance, and other performance characteristics of the final negative electrode material product.

[0093] In some embodiments, the bias voltage range is from -500V to 0V, excluding 0V, and may be, for example, -500V, -400V, -300V, -200V, -100V, -50V, or -0.1V, and may of course be other values ​​within the above range, and is not limited thereto.

[0094] In some embodiments, prior to performing the plasma-enhanced chemical vapor deposition, the vacuum pressure is less than 1.0 Torr.

[0095] In some embodiments, the operating pressure of the plasma-enhanced chemical vapor deposition is in the range of 500 Pa to 5000 Pa, and may be, for example, 500 Pa, 1000 Pa, 2000 Pa, 3000 Pa, 4000 Pa, or 5000 Pa. Of course, other values ​​within the above range are also possible and are not limited thereto. Selecting a pressure within this range is advantageous for surface treatment efficiency, and allows the plasma treatment intensity to be controlled to set the specific surface area of ​​the negative electrode material within a preferred range.

[0096] In some embodiments, the deposition temperature range of the plasma-enhanced chemical vapor deposition is 200°C to 800°C, and specifically may be 200°C, 300°C, 400°C, 500°C, 600°C, 700°C, or 800°C, etc., and may of course be other values ​​within the above range, and is not limited thereto. By selecting a reasonable processing temperature, the silicon-based core of the negative electrode material can be controlled to have a preferred crystal form.

[0097] In some embodiments, the flow rate of the gas-phase reforming source ranges from 200 ml / min to 5000 ml / min, and may be, for example, 200 ml / min, 300 ml / min, 400 ml / min, or 5000 ml / min, and may also be other values ​​within the range, and is not limited thereto. By selecting an appropriate flow rate and controlling the throughput of the reforming source, the ratio of the relevant elements can be controlled.

[0098] In some embodiments, the reforming gas source comprises a reactive gas, which comprises hydrogen gas, a nitrogen-containing gas, a sulfur-containing gas, and a halogen source gas. Specifically, the nitrogen-containing gas may be one or more of nitrogen gas and ammonia gas, the sulfur-containing gas may be hydrogen sulfide, and the halogen source gas may be one or more of fluorine gas, chlorine gas, bromine gas, iodine, hydrogen bromide, hydrogen iodide, and carbon tetrafluoride. When the reforming gas source comprises iodine, the added iodine source may be gaseous or solid. Preferably, in order to control the amount of iodine added, the added iodine source is solid iodine. The solid iodine is easily sublimated into gas and mixed with other gas components in the reforming gas source. Of course, those skilled in the art may select other types of nitrogen-containing gas, sulfur-containing gas, and halogen source gas, as long as they are easy to deposit nitrogen element, sulfur element, and halogen element on the precursor.

[0099] In some embodiments, the modified gas phase source further comprises a protective gas comprising one or more of argon gas, krypton gas, nitrogen gas, neon gas, and helium gas.

[0100] In some specific embodiments, the volume ratio of hydrogen gas to protective gas is in the range of 1:(0.1-5), specifically 1:0.1, 1:1, 1:2, 1:3, 1:4, 1:5, or other values ​​within the range. By selecting the volume ratio of hydrogen gas to protective gas within the range, it is advantageous to adjust the H content within a preferred range.

[0101] In some embodiments, the volume ratio of hydrogen gas to nitrogen-containing gas is 1:(0-1.2), specifically 1:0.05, 1:0.1, 1:0.3, or other values ​​within the range.

[0102] In some embodiments, the volume ratio of hydrogen gas to sulfur-containing gas is 1:(0-0.2), specifically 1:0.01, 1:0.03, 1:0.05, 1:0.15, 1:0.20, or other values ​​within the range.

[0103] In some embodiments, the volume ratio of hydrogen gas to halogen source gas is 1:(0-0.05), specifically 1:0.015, 1:0.01, 1:0.03, 1:0.05, or other values ​​within the range.

[0104] In some embodiments, after step S200, the manufacturing method further includes sieving the reformed product to obtain a product negative electrode material with a target particle size.

[0105] In a third aspect, One embodiment of the present application provides a secondary battery (e.g., a lithium-ion battery, a sodium-ion battery, etc.) including a housing, an electrode assembly, and an electrolyte solution / electrolyte, both of which are located within the housing.

[0106] The housing may be a packaging bag sealed with a sealing film (e.g., aluminum plastic film), and the secondary battery may be a soft-pack battery. In other embodiments, the secondary battery may be a steel-cased battery, an aluminum-cased battery, or the like.

[0107] FIG. 3 is a schematic diagram showing a battery in a discharged state, i.e., during operation. As shown in FIG. 3, the electrode assembly includes a positive electrode piece 110, a negative electrode piece 120, and a separator 130, with the separator disposed between the positive and negative electrode pieces. The electrode assembly may have a stacked structure in which the positive electrode piece, the separator, and the negative electrode piece are alternately stacked in sequence. In some other embodiments, the electrode assembly may have a wound structure in which the positive electrode piece, the separator, and the negative electrode piece are stacked in sequence and then wound.

[0108] positive electrode piece The cathode piece 110 includes a cathode current collector 111 and a cathode active material layer 112 disposed on at least one surface of the cathode current collector. The cathode current collector may be an aluminum foil, a nickel foil, or any composite current collector disclosed in the prior art, such as, but not limited to, a current collector formed by combining the conductive foil with a polymer base. The cathode active material layer includes a cathode active material including a compound that reversibly absorbs and releases metal ions. In some embodiments, the cathode active material may include a lithium transition metal composite oxide, a sodium transition metal composite oxide, or the like. The lithium transition metal composite oxide contains lithium and at least one element selected from cobalt, manganese, and nickel. In some embodiments, the cathode active material may be lithium cobalt oxide (LiCoO), a lithium nickel manganese cobalt ternary material (NCM), lithium manganese oxide (LiMnO), or lithium nickel manganese oxide (LiNi). 0.5 Mn 1.5 The material may include, but is not limited to, at least one of lithium iron phosphate (LiFePO4) or lithium iron phosphate (LiFePO4).

[0109] Negative electrode piece The negative electrode piece 120 includes a negative electrode current collector 121 and a negative electrode active material layer 122 formed on at least one surface of the negative electrode current collector. The negative electrode current collector may be at least one of copper foil, nickel foil, stainless steel foil, titanium foil, or a carbon-based current collector, or may be any composite current collector disclosed in the prior art, such as a current collector formed by combining the conductive foil with a polymer base, but is not limited to these. The negative electrode active material layer includes a negative electrode material.

[0110] During the running period of the battery, i.e., when the battery is in a discharged state, metal ions 140 (e.g., lithium ions) in the negative electrode are released from the crystal lattice of the negative electrode material and are absorbed into the crystal lattice of the positive electrode material by being transported through the separator 130 by the electrolyte solution / electrolyte.

[0111] Conversely, when the battery is charged by applying power to an external circuit, metal ions (e.g., lithium ions) at the positive electrode are released from the crystal lattice of the positive electrode material due to oxidation of the positive electrode material, and are transported to the negative electrode by passing through the separator via the electrolyte solution / electrolyte. At the same time, the negative electrode material undergoes a reduction reaction, and the metal ions are absorbed into the crystal lattice of the negative electrode material.

[0112] By shuttling metal ions between the positive and negative electrodes, batteries can undergo the process of discharge and charge over thousands of cycles.

[0113] As will be apparent to those skilled in the art, the above-described negative electrode material and battery manufacturing method are merely examples, and other methods commonly used in the art may be employed without departing from the scope of the present description. [Example]

[0114] The present invention will be further described below with reference to several examples. Note that the present invention is not limited to the specific examples below. Appropriate modifications can be made within the scope of the claims.

[0115] Measurement method: 1. Particle size: Particle size was measured using Mastersizer 3000 laser diffraction technology. Particle size measurement is completed by measuring the intensity of scattered light when a laser beam passes through a dispersed particle sample. The data is then analyzed to form a scattering spectrogram to calculate the particle size distribution. D50 is the particle size corresponding to the cumulative volume particle size distribution percentage of a sample reaching 50%. Its physical meaning is that particles with a particle size larger than this size account for 50%, and particles smaller than this size also account for 50%. D50 is also called the median diameter. D90 particle size, D50 particle size, and D10 particle size are the equivalent diameters (average particle size) of the largest particle when the cumulative distribution on the distribution curve is 90%, 50%, and 10%, respectively. 2. Specific surface area: The specific surface area is measured using a US Micro Tristar 3000 specific surface area and pore size analyzer. 3. Tap density: 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. Thickness of the coating layer (carbon layer): The material is cut using an FIB-SEM device and measured in the SEM to obtain the average thickness of the coating layer. 5. Powder conductivity: The volume resistivity of the negative electrode material powder was measured using the four-point probe method. The resistance of the powder was measured at five pressure points: 4KN, 8KN, 12KN, 16KN, and 20KN. The computer then automatically calculated the conductivity and resistivity of the negative electrode material powder. 6. Testing the water mass content of the negative electrode material: Measured by gravimetric method. The material was placed in a vacuum oven at 250°C and baked for 48 hours to dry. The weight loss before and after baking was measured and converted into water content. 7. pH test of negative electrode material: 5 g of material was mixed with 45 g of deionized water, and after ultrasonic treatment for 30 minutes, measurements were taken using an electronic pH meter. 8. Pore volume: Measurement was carried out using a BET micropore specific surface area / pore size analyzer according to the test manual for the device. 9. Element content test: Nitrogen and hydrogen content measurements were performed using an ONH2000 oxygen, nitrogen, and hydrogen analyzer. The sample and flux were placed in a graphite crucible and heated to a maximum temperature of 3000°C until melted. N2 and H2 were generated by high-temperature decomposition and transported to a thermal conductivity cell by a carrier gas for measurement. The measurement volume was 10±1 mg. The flux was nickel foil. The measurement recalibration path was set to High N / H. The degassing time was 30 seconds, the degassing power was 5 kW, the rinse time was set to 20 seconds, the stabilization time was set to 40 seconds, the infrared integration delay time was set to 2 seconds, the analysis time was 60 seconds, and the analysis power was 4 kW. Each sample was tested twice, and the average value was calculated, leaving four decimal places. Sulfur content testing was performed using an ELTRA CS-i infrared carbon-sulfur analyzer. A certain amount of sample was weighed and placed in a ceramic crucible. A flux was added, and the sample was placed in a high-frequency furnace and burned through high-purity oxygen to produce carbon dioxide and sulfur dioxide. The carbon and sulfur content of the resulting gas was measured using an infrared detector. A multi-component flux was selected, the injection amount was 50 g, the blank analysis time was 40 s, the furnace body rinse time was 2 s, the furnace body rinse airflow was 180 L / h, the stabilization time was 45–60 s, and the analysis carrier gas flow rate was 180 L / h. Halide ion content detection: Tests were performed using the ICS-6000 in accordance with GB / T 24533-2019. The leachate concentration was 25 nM, the flow rate was 0.30 mL / min, the sample volume was 0.7 g, and the ultrasonic time was 3 minutes. The sample was subjected to natural sedimentation. 0.7 ± 0.01 g of sample was accurately weighed and dispersed in 50 mL of first-grade water. After manual dispersion and stirring for 5 minutes, external ultrasonic waves were applied at 240 W for 3 minutes. 10.Electrical performance test: According to the Betelrui Company's work instruction manual BTRTC / ZY / 01-020 "Button Battery Method Work Instruction Manual", a button battery was assembled. The electrodes were made of metal lithium sheets, the separator was a PP-PE-PP composite film, the diameter was 19.2 mm, the electrolyte composition ratio was EC / EMC / DMC=1 / 1 / 1, and the lithium salt (LiPF6) concentration was 1.05 mol / L. Capacity test: Batteries were manufactured using the negative electrode materials prepared in the examples and comparative examples, and tested using a button battery charge / discharge device. The batteries were charged to 10 mV at a constant current of 0.1 C, then charged to 5 mV at a constant current of 0.02 C, and then discharged to 1.5 V at a constant current of 0.1 C. 50-cycle test of half cell: Batteries were manufactured using the negative electrode materials manufactured in the examples and comparative examples, and tested using a button battery charge / discharge device. In the first cycle, the battery was discharged at 0.1C to 0.01V, then discharged at 0.01C in increments of 0.01V, then discharged at 0.01C in increments of 0.005V, and then charged at 0.1C to 1.5V; in the second cycle, the battery was discharged at 0.2C to 0.01V, then discharged at 0.02C in increments of 0.02V, then discharged at 0.02C in increments of 0.005V, and then charged at 0.2C to 1.5V; in the third cycle, the battery was discharged at 0.2C to 0.01V, then discharged at 0.02C in increments of 0.02V, then discharged at 0.02C in increments of 0.005V, and then charged at 0.2C to 1.5V; In the 4th cycle, discharge at 0.5C to 0.01V, gradually decrease discharge at 0.05C to 0.01V, discharge at 0.05C to 0.005V, and charge at 0.5C to 1.5V; in the 4th to 50th cycles, discharge at 1C to 0.01V, gradually decrease discharge at 0.1C to 0.01V, discharge at 0.1C to 0.005V, and charge at 1C to 1.5V; in the 51st cycle, discharge at 0.1C to 0.01V, gradually decrease discharge at 0.01C to 0.01V, and discharge at 0.01C to 0.005V. Whole battery performance test: The whole battery performance was measured using an 18650 small cylindrical battery, which combined silicon-based materials and graphite with a capacity of 450mAh / g, and the relevant performance measurements were completed according to the methods specified in the Chinese national standard GB / T 31486-2015.

[0116] Example 1 The method for producing the negative electrode material includes the following steps. (1) Silicon monoxide was coated with graphite to obtain 1000 g of precursor (carbon content: 5 wt%), which was then rinsed with deionized water for 30 min and vacuum dried for 12 h at 75°C. Afterwards, the precursor was sieved to obtain a precursor with the target particle size. (2) The precursor was placed in a bias voltage stage in a plasma reaction chamber, and the pressure was evacuated to below 0.1 Pa. Then, a gaseous reforming source was introduced at a flow rate of 3000 ml / min. The gaseous reforming source was a mixture of hydrogen gas, argon gas, ammonia gas, hydrogen sulfide, and chlorine gas, with a volume ratio of hydrogen gas, argon gas, ammonia gas, hydrogen sulfide, and chlorine gas of 1:1:0.2:0.03:0.01. The pressure in the reaction chamber was controlled to 2000 Pa using a vacuum pump. The plasma was then turned on to generate plasma light, and a bias voltage of -200 V was applied to the reaction platform in the reaction chamber. After the plasma stabilized, the pressure in the reaction chamber was further adjusted to maintain it at 2000 Pa. The reaction was then timed to 24 hours, and the reaction temperature was controlled between 450°C and 500°C to obtain a reformed product. (3) The modified product was sieved and vacuum dried at 75°C for 12 hours to obtain the negative electrode material product. The specific electrochemical performance of the negative electrode material product prepared in Example 1 of the present application is shown in Table 2. The negative electrode material product prepared in Example 1 of the present application includes a silicon-based active material and a carbon material, the carbon material being located on at least a portion of the surface of the silicon-based active material, and the negative electrode material including hydrogen, halogen, nitrogen, and sulfur elements. The specific measurement data are shown in Table 1. The negative electrode material product produced in Example 1 of the present invention has a median diameter of 5.3 μm, a carbon content of 4.95 wt%, and a tap density of 0.98 g / cm 3 , moisture content 0.21%, pH = 9.63, specific surface area 1.88m 2 / g. In addition, the negative electrode material product produced in Example 1 has one characteristic peak of pore volume within each of the pore diameter ranges of 240 Å to 280 Å, 290 Å to 320 Å, 340 Å to 390 Å, and 410 Å to 460 Å, as shown in FIG. 4.

[0117] Example 2 The method for producing the negative electrode material includes the following steps. (1) Lithium-doped silicon monoxide was coated with graphene to obtain 1000 g of precursor (carbon mass content: 5 wt%). The precursor was centrifuged and rinsed with deionized water for 2 hours, and then vacuum dried at 80°C for 24 hours. After that, the precursor was sieved to obtain a precursor with the target particle size. (2) The precursor was placed in a bias voltage stage in a plasma reaction chamber, and the chamber was evacuated to a pressure of less than 0.1 Pa. A gaseous reforming source was introduced at a flow rate of 3000 ml / min. The gaseous reforming source was a mixture of hydrogen gas, argon gas, ammonia gas, hydrogen sulfide, and carbon tetrafluoride in a volume ratio of 1:1:0.1:0.05:0.05. The pressure in the reaction chamber was controlled to 2000 Pa using a vacuum pump. The plasma was then turned on to generate plasma light, and a bias voltage of -200 V was applied to the reaction platform in the reaction chamber. After the plasma stabilized, the pressure in the reaction chamber was further adjusted to maintain it at 2000 Pa. The reaction was then timed to 24 hours, and the reaction temperature was controlled between 450°C and 500°C. A reformed product was obtained. (3) The modified product was sieved and then vacuum dried for 12 hours at a drying temperature of 75°C to obtain a negative electrode material product. The specific electrochemical performance of the negative electrode material product prepared in Example 2 of the present application is shown in Table 2. The negative electrode material product prepared in Example 2 of the present application includes a silicon-based active material and a carbon material, the carbon material being located on at least a portion of the surface of the silicon-based active material, and the negative electrode material including hydrogen, halogen, nitrogen, and sulfur elements. The specific measurement data are shown in Table 1. The negative electrode material product produced in Example 2 had a median diameter of 5.62 μm, a carbon content of 5.01 wt%, and a tap density of 0.98 g / cm 3 , moisture 0.17%, pH = 10.47, specific surface area 1.92 m 2 / g. Furthermore, the negative electrode material product produced in Example 2 has one characteristic peak of pore volume in each of the pore diameter ranges of 240 Å to 280 Å, 290 Å to 320 Å, 340 Å to 390 Å, and 410 Å to 460 Å.

[0118] Example 3 The method for producing the negative electrode material includes the following steps. (1) Silicon monoxide was coated with graphite to obtain 1000 g of precursor (carbon content: 5 wt%), which was then rinsed with deionized water for 30 min and vacuum dried for 12 h at 75°C. Afterwards, the precursor was sieved to obtain a precursor with the target particle size. (2) The precursor was placed on a bias voltage stage in the reaction chamber, and the pressure was evacuated to below 0.1 Pa. Then, a gaseous reforming source was introduced at a flow rate of 3000 ml / min. The gaseous reforming source was a mixture of hydrogen gas, argon gas, ammonia gas, hydrogen sulfide, and hydrogen bromide in a volume ratio of 1:1:0.15:0.03:0.03. The pressure in the reaction chamber was controlled to 3000 Pa using a vacuum pump. The plasma was then turned on to generate plasma light, and a bias voltage of -200 V was applied to the reaction platform in the reaction chamber. After the plasma stabilized, the pressure in the reaction chamber was further adjusted to maintain it at 3000 Pa. The reaction was then timed to 24 hours, and the reaction temperature was controlled between 650 and 700°C to obtain a reformed product. (3) The modified product was sieved and then vacuum dried for 12 hours at a drying temperature of 75°C to form a negative electrode material product. The specific electrochemical performance of the negative electrode material product prepared in Example 3 of the present application is shown in Table 2. The negative electrode material product prepared in Example 3 includes a silicon-based active material and a carbon material, the carbon material being located on at least a portion of the surface of the silicon-based active material, and the negative electrode material including hydrogen, halogen, nitrogen, and sulfur elements. The specific measurement data are shown in Table 1. The negative electrode material product produced in Example 3 had a median diameter of 5.12 μm, a carbon content of 4.95 wt%, and a tap density of 0.98 g / cm 3 , moisture 0.07%, pH=9.51, specific surface area 2.49m 2 / g. In addition, the negative electrode material product prepared in Example 3 has one characteristic peak of pore volume in each of the pore diameter ranges of 240 Å to 280 Å, 290 Å to 320 Å, 340 Å to 390 Å, and 410 Å to 460 Å.

[0119] Example 4 The method for producing the negative electrode material includes the following steps. (1) Lithium-doped silicon monoxide was coated with graphite to obtain 1000 g of precursor (carbon mass content: 5 wt%). The precursor was centrifuged and rinsed with deionized water for 2 hours, and then vacuum dried at 80°C for 24 hours. After that, the precursor was sieved to obtain a precursor with the target particle size. (2) The precursor was placed on a bias voltage stage in the reaction chamber, and the chamber was evacuated to a pressure of less than 0.1 Pa. A gaseous reforming source was then introduced at a flow rate of 3000 ml / min. The gaseous reforming source was a mixture of hydrogen gas, argon gas, ammonia gas, hydrogen sulfide, and hydrogen iodide in a volume ratio of 1:1.5:0.05:0.01:0.01. The pressure in the reaction chamber was then controlled to 3000 Pa using a vacuum pump. The plasma was then turned on to generate plasma light, and a bias voltage of -200 V was applied to the reaction platform in the reaction chamber. After the plasma stabilized, the pressure in the reaction chamber was further adjusted to maintain it at 3000 Pa. The reaction was then timed to 24 hours, and the reaction temperature was controlled between 700 and 750°C, resulting in the production of a reformed product. (3) The modified product was sieved and then vacuum dried for 12 hours at a drying temperature of 75°C to form a negative electrode material product. The specific electrochemical performance of the negative electrode material product prepared in Example 4 of the present application is shown in Table 2. The negative electrode material product prepared in Example 4 includes a silicon-based active material and a carbon material, the carbon material being located on at least a portion of the surface of the silicon-based active material, and the negative electrode material including hydrogen, halogen, nitrogen, and sulfur elements. The specific measurement data are shown in Table 1. The negative electrode material product produced in Example 4 had a median diameter of 5.35 μm, a carbon content of 4.95 wt%, and a tap density of 0.98 g / cm 3 , moisture 0.17%, pH = 10.47, specific surface area 1.92 m 2 / g. Furthermore, the negative electrode material product produced in Example 4 has one characteristic peak of pore volume in each of the pore diameter ranges of 240 Å to 280 Å, 290 Å to 320 Å, 340 Å to 390 Å, and 410 Å to 460 Å.

[0120] Example 5 The method for producing the negative electrode material includes the following steps. (1) Silicon monoxide was coated using graphite to obtain 1000 g of precursor, which was then rinsed with deionized water for 30 minutes and vacuum dried for 12 hours at 75°C. Afterwards, the precursor was sieved to obtain a precursor of the target particle size. (2) The precursor was placed on a bias voltage stage in the reaction chamber, and the pressure was evacuated to below 0.1 Pa. Then, a gaseous reforming source was introduced at a flow rate of 3000 ml / min. The gaseous reforming source was a mixture of hydrogen gas, argon gas, ammonia gas, hydrogen sulfide, and chlorine gas in a volume ratio of 1:1:0.05:0.015:0.05. The pressure in the reaction chamber was controlled to 3000 Pa using a vacuum pump. The plasma was then turned on to generate plasma light, and a bias voltage of -200 V was applied to the reaction platform in the reaction chamber. After the plasma stabilized, the pressure in the reaction chamber was further adjusted to maintain it at 3000 Pa. Then, the reaction was timed to 24 hours, and the reaction temperature was controlled between 650 and 700°C, resulting in a reformed product. (3) The modified product was sieved and then vacuum dried for 12 hours at a drying temperature of 75°C to form a negative electrode material product. The specific electrochemical performance of the negative electrode material product prepared in Example 5 of the present application is shown in Table 2. The negative electrode material product prepared in Example 5 includes a silicon-based active material and a carbon material, the carbon material being located on at least a portion of the surface of the silicon-based active material, and the negative electrode material including hydrogen, halogen, nitrogen, and sulfur elements. The specific measurement data are shown in Table 1. The negative electrode material product produced in Example 5 had a median diameter of 5.08 μm, a carbon content of 5.32 wt%, and a tap density of 0.98 g / cm 3 , moisture 0.05%, pH=9.45, specific surface area 2.23m 2 / g. In addition, the negative electrode material product prepared in Example 5 has one characteristic peak of pore volume in each of the pore diameter ranges of 240 Å to 280 Å, 290 Å to 320 Å, 340 Å to 390 Å, and 410 Å to 460 Å.

[0121] Example 6 The method for producing the negative electrode material includes the following steps. (1) A mixture of silicon monoxide and lithium silicate was coated with a mixture of graphite and graphene to obtain 1000 g of precursor (with a carbon content of 5 wt%). The precursor was rinsed with deionized water for 30 min and then vacuum dried for 10 h at a drying temperature of 80°C. After that, the precursor was sieved to obtain a precursor with the target particle size. (2) The precursor was placed on a bias voltage stage in the reaction chamber, and the pressure was evacuated to below 0.1 Pa. Then, a gaseous reforming source was introduced at a flow rate of 5000 ml / min. The gaseous reforming source was a mixture of hydrogen gas, argon gas, ammonia gas, hydrogen sulfide, and chlorine gas in a volume ratio of 1:5:0.3:0.015:0.01. The pressure in the reaction chamber was controlled to 2000 Pa using a vacuum pump. The plasma was then turned on to generate plasma light, and a bias voltage of -200 V was applied to the reaction platform in the reaction chamber. After the plasma stabilized, the pressure in the reaction chamber was further adjusted to maintain it at 2000 Pa. The reaction was then timed to 24 hours, and the reaction temperature was controlled between 450°C and 500°C to obtain a reformed product. (3) The modified product was sieved and then vacuum dried for 12 hours at a drying temperature of 75°C to form a negative electrode material product. The specific electrochemical performance of the negative electrode material product prepared in Example 6 of the present application is shown in Table 2. The negative electrode material product prepared in Example 6 includes a silicon-based active material and a carbon material, the carbon material being located on at least a portion of the surface of the silicon-based active material, and the negative electrode material including hydrogen, halogen, nitrogen, and sulfur elements. The specific measurement data are shown in Table 1. The negative electrode material product produced in Example 6 had a median diameter of 8.4 μm, a carbon content of 4.89 wt%, and a tap density of 0.95 g / cm 3 , moisture 0.08%, pH=9.55, specific surface area 1.54m 2 / g. Furthermore, the negative electrode material product produced in Example 6 has one characteristic peak of pore volume in each of the pore diameter ranges of 240 Å to 280 Å, 290 Å to 320 Å, 340 Å to 390 Å, and 410 Å to 460 Å.

[0122] Example 7 The method for producing the negative electrode material includes the following steps. (1) Silicon monoxide was coated with amorphous carbon to obtain 1000 g of precursor (carbon content: 5 wt%), which was then rinsed with deionized water for 30 min and vacuum dried for 12 h at 75°C. Afterwards, the precursor was sieved to obtain a precursor with the target particle size. (2) The precursor was placed in a bias voltage stage in the reaction chamber, and the chamber was evacuated to a pressure of less than 0.1 Pa. A gaseous reforming source was introduced at a flow rate of 3000 ml / min. The gaseous reforming source was a mixture of hydrogen gas, argon gas, nitrogen gas, hydrogen sulfide, and iodine, with a volume ratio of 1:5:0.05:0.2:0.1. The pressure in the reaction chamber was controlled to 5000 Pa using a vacuum pump. The plasma was then turned on to generate plasma light, and a bias voltage of -200 V was applied to the reaction platform in the reaction chamber. After the plasma stabilized, the pressure in the reaction chamber was further adjusted to maintain it at 3000 Pa. The reaction was then timed to 24 hours, and the reaction temperature was controlled between 500°C and 800°C, resulting in the formation of a reformed product. (3) The modified product was sieved and then vacuum dried for 12 hours at a drying temperature of 75°C to form a negative electrode material product. The specific electrochemical performance of the negative electrode material product prepared in Example 7 of the present application is shown in Table 2. The negative electrode material product prepared in Example 7 includes a silicon-based active material and a carbon material, the carbon material being located on at least a portion of the surface of the silicon-based active material, and the negative electrode material including hydrogen, halogen, nitrogen, and sulfur elements. The specific measurement data are shown in Table 1. The negative electrode material product produced in Example 7 had a median diameter of 5.5 μm, a carbon content of 6.54 wt%, and a tap density of 0.98 g / cm 3 , moisture content 0.21%, powder conductivity (at 20 kN) 4.39 S / cm, pH = 9.63, specific surface area 1.88 m 2 / g. Furthermore, the negative electrode material product produced in Example 7 has one characteristic peak of pore volume in each of the pore diameter ranges of 240 Å to 280 Å, 290 Å to 320 Å, 340 Å to 390 Å, and 410 Å to 460 Å.

[0123] Example 8 The method for producing the negative electrode material includes the following steps. (1) Magnesium-doped silicon monoxide was coated with graphite to obtain 1000 g of precursor (carbon content: 5 wt%), which was rinsed with deionized water for 30 min and then vacuum dried for 12 h at 75°C. After that, the precursor was sieved to obtain a precursor with the target particle size. (2) The precursor was placed on a bias voltage stage in the reaction chamber, and the pressure was evacuated to below 0.1 Pa. Then, a gaseous reforming source was introduced at a flow rate of 3000 ml / min. The gaseous reforming source was a mixture of hydrogen gas, argon gas, nitrogen gas, hydrogen sulfide, and chlorine gas in a volume ratio of 1:1:0.15:0.01:0.015. The pressure in the reaction chamber was controlled to 2000 Pa using a vacuum pump. Then, the plasma was turned on to generate plasma light, and a bias voltage of -200 V was applied to the reaction platform in the reaction chamber. After the plasma stabilized, the pressure in the reaction chamber was further adjusted to maintain it at 2000 Pa. Then, the reaction was timed, and the reaction time was set to 24 hours. The reaction temperature was controlled between 450°C and 500°C, and a reformed product was obtained. (3) The modified product was sieved and then vacuum dried for 12 hours at a drying temperature of 75°C to form a negative electrode material product. The specific electrochemical performance of the negative electrode material product prepared in Example 8 of the present application is shown in Table 2. The negative electrode material product prepared in Example 8 includes a silicon-based active material and a carbon material, the carbon material being located on at least a portion of the surface of the silicon-based active material, and the negative electrode material including hydrogen, halogen, nitrogen, and sulfur elements. The specific measurement data are shown in Table 1. The negative electrode material product produced in Example 8 had a median diameter of 5.13 μm, a carbon content of 4.98 wt%, and a tap density of 0.98 g / cm3 , moisture content 0.22%, pH=9.61, specific surface area 1.85m 2 / g. Furthermore, the negative electrode material product produced in Example 8 has one characteristic peak of pore volume in each of the pore diameter ranges of 240 Å to 280 Å, 290 Å to 320 Å, 340 Å to 390 Å, and 410 Å to 460 Å.

[0124] Example 9 The method for producing the negative electrode material includes the following steps. (1) The lithium aluminum doped silicon monoxide mixture was coated with graphite to obtain 1000 g of precursor (carbon content: 5 wt%), which was rinsed with deionized water for 30 min and then vacuum dried for 12 h at 75°C. After that, the precursor with the target particle size was obtained by sieving. (2) The precursor was placed in a bias voltage stage in a reaction chamber, which was then evacuated to a pressure of less than 0.1 Pa. A gaseous reforming source was then introduced at a flow rate of 3000 ml / min. The gaseous reforming source was a mixture of hydrogen gas, argon gas, nitrogen gas, ammonia gas, hydrogen sulfide, chlorine gas, and iodine, with a volume ratio of 1:1:0.005:0.005:0.04:0.005:0.005. The pressure in the reaction chamber was then controlled to 2000 Pa using a vacuum pump. The plasma was then turned on to generate plasma light, and a bias voltage of -200 V was applied to the reaction platform in the reaction chamber. After the plasma stabilized, the pressure in the reaction chamber was further adjusted to maintain it at 2000 Pa. The reaction was then timed to 24 hours, and the reaction temperature was controlled between 450°C and 500°C. A reformed product was obtained. (3) The modified product was sieved and then vacuum dried for 12 hours at a drying temperature of 75°C to form a negative electrode material product. The specific electrochemical performance of the negative electrode material product prepared in Example 9 of the present application is shown in Table 2. The negative electrode material prepared in Example 9 of the present application includes a silicon-based active material and a carbon material, the carbon material being located on at least a portion of the surface of the silicon-based active material, and the negative electrode material including hydrogen, halogen, nitrogen, and sulfur elements. Specific measurement data are shown in Table 1. The negative electrode material produced in Example 9 of the present invention had a median diameter of 5.18 μm, a carbon content of 4.99 wt%, and a tap density of 0.98 g / cm 3 , moisture 0.15%, pH=9.83, specific surface area 1.98m 2 / g. Furthermore, the negative electrode material product produced in Example 9 has one characteristic peak of pore volume in each of the pore diameter ranges of 240 Å to 280 Å, 290 Å to 320 Å, 340 Å to 390 Å, and 410 Å to 460 Å.

[0125] Comparative Example 1 The difference from Example 1 is that no plasma treatment is performed. The negative electrode material produced in Comparative Example 1 had a median diameter of 5.21 μm, a carbon content of 4.98 wt%, and a tap density of 0.98 g / cm 3 , moisture 0.25%, pH=9.69, specific surface area 1.81m 2 / g. Furthermore, the negative electrode material product produced in Comparative Example 1 has a large and broad peak in the pore diameter range of 240 Å to 460 Å.

[0126] Comparative Example 2 The method for producing the negative electrode material includes the following steps. The differences from Example 2 are: (2) The precursor was placed on a bias voltage stage in the reaction chamber, and the pressure was evacuated to below 0.1 Pa. Then, a gaseous reforming source was introduced at a flow rate of 3000 ml / min. The gaseous reforming source was a mixture of hydrogen gas, argon gas, ammonia gas, and hydrogen sulfide in a volume ratio of 0.5:1:1:1. The pressure in the reaction chamber was controlled to 4000 Pa using a vacuum pump. Then, the plasma was turned on to generate plasma light, and a bias voltage of -500 V was applied to the reaction platform in the reaction chamber. After the plasma stabilized, the pressure in the reaction chamber was further adjusted to maintain it at 2000 Pa. Then, the reaction was timed to 24 hours, and the reaction temperature was measured between 450°C and 500°C. A reformed product was obtained. The negative electrode material produced in Comparative Example 2 had a median diameter of 5.38 μm, a carbon content of 5.05 wt%, and a tap density of 0.98 g / cm 3 , moisture 0.13%, pH = 10.47, specific surface area 1.92 m 2 / g. Furthermore, the negative electrode material product produced in Comparative Example 2 has one characteristic peak of pore volume in each of the pore diameter ranges of 290 Å to 320 Å, 340 Å to 390 Å, and 410 Å to 460 Å.

[0127] Comparative Example 3 The method for producing the negative electrode material includes the following steps. The differences from Example 2 are: (2) The precursor was placed in a bias voltage stage in a plasma reaction chamber, and the chamber was evacuated to a pressure of less than 0.1 Pa. A gaseous reforming source was introduced at a flow rate of 2000 ml / min. The gaseous reforming source was a mixture of hydrogen gas, argon gas, ammonia gas, and carbon tetrafluoride in a volume ratio of 1:1:0.1:0.03. The pressure in the reaction chamber was controlled to 1500 Pa using a vacuum pump. The plasma was then turned on to generate plasma light, and a bias voltage of -200 V was applied to the reaction platform in the reaction chamber. After the plasma stabilized, the pressure in the reaction chamber was further adjusted to maintain 1500 Pa. The reaction was then timed to 24 hours, and the reaction temperature was controlled between 400°C and 450°C, resulting in the formation of a reformed product. The negative electrode material produced in Comparative Example 3 had a median diameter of 5.36 μm, a carbon content of 4.96 wt%, and a tap density of 0.97 g / cm 3 , moisture 0.09%, pH=9.53, specific surface area 1.99m 2 / g. Furthermore, the negative electrode material product produced in Comparative Example 3 has one characteristic peak of pore volume in each of the pore diameter ranges of 290 Å to 320 Å, 340 Å to 390 Å, and 410 Å to 460 Å.

[0128] Comparative Example 4 The method for producing the negative electrode material includes the following steps. The differences from Example 2 are: (2) The precursor was placed on a bias voltage stage in a plasma reaction chamber, and the chamber was evacuated to a pressure of less than 0.1 Pa. A gaseous reforming source was then introduced at a flow rate of 2000 ml / min. The gaseous reforming source was a mixture of hydrogen gas, argon gas, and ammonia gas in a volume ratio of 1:1:0.03. The pressure in the reaction chamber was then controlled to 1500 Pa using a vacuum pump. The plasma was then turned on to generate plasma light, and a bias voltage of -200 V was applied to the reaction platform in the reaction chamber. After the plasma stabilized, the pressure in the reaction chamber was further adjusted to maintain 1500 Pa. The reaction was then timed to 24 hours, and the reaction temperature was controlled between 400°C and 450°C, resulting in the formation of a reformed product. The negative electrode material produced in Comparative Example 4 had a median diameter of 5.03 μm, a carbon content of 5.55 wt%, and a tap density of 0.98 g / cm 3 , moisture 0.20%, pH=9.38, specific surface area 1.79m 2 / g. Furthermore, the negative electrode material product produced in Comparative Example 4 has one characteristic peak of pore volume in each of the pore diameter ranges of 290 Å to 320 Å, 340 Å to 390 Å, and 410 Å to 460 Å.

[0129] Comparative Example 5 The method for producing the negative electrode material includes the following steps. The differences from Example 2 are: (2) The precursor was placed in a bias voltage stage in a plasma reaction chamber, and the pressure was evacuated to below 0.1 Pa. Then, a gaseous reforming source was introduced at a flow rate of 2000 ml / min. The gaseous reforming source was a mixture of hydrogen gas, argon gas, ammonia gas, hydrogen sulfide, and carbon tetrafluoride in a volume ratio of 1:1:0.01:0.03:0.01. The pressure in the reaction chamber was controlled to 2000 Pa using a vacuum pump. The plasma was then turned on to generate plasma light, and a bias voltage of -200 V was applied to the reaction platform in the reaction chamber. After the plasma stabilized, the pressure in the reaction chamber was further adjusted to maintain it at 2000 Pa. The reaction was then timed to 24 hours, and the reaction temperature was controlled between 400°C and 450°C. A reformed product was obtained. The negative electrode material produced in Comparative Example 5 had a median diameter of 5.58 μm, a carbon content of 5.65 wt%, and a tap density of 0.98 g / cm 3 , moisture 0.18%, pH=9.7, specific surface area 2.18m 2 / g. Furthermore, the negative electrode material product produced in Comparative Example 5 has one characteristic peak of pore volume in each of the pore diameter ranges of 240 Å to 280 Å, 290 Å to 320 Å, 340 Å to 390 Å, and 410 Å to 460 Å.

[0130] Comparative Example 6 The method for producing the negative electrode material includes the following steps. The differences from Example 2 are: (2) The precursor was placed in a bias voltage stage in a plasma reaction chamber, and after evacuating to below 0.1 Pa, a gaseous reforming source was introduced at a flow rate of 4000 ml / min. The gaseous reforming source was a mixture of hydrogen gas, argon gas, ammonia gas, and carbon tetrafluoride in a volume ratio of 1:1:0.05:0.02. The pressure in the reaction chamber was controlled to 3000 Pa using a vacuum pump. The plasma was then turned on to generate plasma light, and a bias voltage of -200 V was applied to the reaction platform in the reaction chamber. After the plasma stabilized, the pressure in the reaction chamber was further adjusted to maintain it at 3000 Pa. The reaction was then timed to 24 hours, and the reaction temperature was controlled between 450°C and 500°C, resulting in a reformed product. The negative electrode material produced in Comparative Example 6 had a median diameter of 5.6 μm, a carbon content of 4.96 wt%, and a tap density of 0.98 g / cm 3 , moisture content 0.22%, pH=9.83, specific surface area 1.90m 2 / g. Furthermore, the negative electrode material product produced in Comparative Example 6 has one characteristic peak of pore volume in each of the pore diameter ranges of 290 Å to 320 Å, 340 Å to 390 Å, and 410 Å to 460 Å.

[0131] Comparative Example 7 The method for producing the negative electrode material includes the following steps. The differences from Example 2 are: (2) The precursor was placed in a bias voltage stage in a plasma reaction chamber, and the chamber was evacuated to a pressure of less than 0.1 Pa. A gaseous reforming source was introduced at a flow rate of 1500 ml / min. The gaseous reforming source was a mixture of hydrogen gas, argon gas, hydrogen sulfide, and carbon tetrafluoride in a volume ratio of 1:1:0.05:0.01. The pressure in the reaction chamber was controlled to 1000 Pa using a vacuum pump. The plasma was then turned on to generate plasma light, and a bias voltage of -200 V was applied to the reaction platform in the reaction chamber. After the plasma stabilized, the pressure in the reaction chamber was further adjusted to maintain it at 1000 Pa. The reaction was then timed to 24 hours, and the reaction temperature was controlled between 250°C and 300°C, resulting in the production of a reformed product. The negative electrode material produced in Comparative Example 7 had a median diameter of 5.14 μm, a carbon content of 4.75 wt%, and a tap density of 0.98 g / cm 3 , moisture 0.09%, pH=9.43, specific surface area 1.68m 2 / g. In addition, the negative electrode material product prepared in Comparative Example 7 has a large and broad peak within the pore diameter range of 240 Å to 460 Å.

[0132] Comparative Example 8 The method for producing the negative electrode material includes the following steps. The differences from Example 2 are: (2) The precursor was placed in a bias voltage stage in a plasma reaction chamber, and the chamber was evacuated to a pressure of less than 0.1 Pa. Then, a gaseous reforming source was introduced at a flow rate of 3000 ml / min. The gaseous reforming source was a mixture of hydrogen gas, argon gas, and hydrogen sulfide in a volume ratio of 1:1:0.05. The pressure in the reaction chamber was controlled to 2000 Pa using a vacuum pump. The plasma was then turned on to generate plasma light, and a bias voltage of -200 V was applied to the reaction platform in the reaction chamber. After the plasma stabilized, the pressure in the reaction chamber was further adjusted to maintain it at 2000 Pa. Then, the reaction was timed to 24 hours, and the reaction temperature was controlled between 350°C and 450°C, resulting in the formation of a reformed product. The negative electrode material produced in Comparative Example 8 had a median diameter of 5.37 μm, a carbon content of 4.96 wt%, and a tap density of 0.98 g / cm 3 , moisture 0.20%, pH=9.61, specific surface area 1.93m 2 / g. Furthermore, the negative electrode material product produced in Comparative Example 8 has a large and broad peak in the pore diameter range of 240 Å to 460 Å. The negative electrode materials produced in Examples 1 to 9 and Comparative Examples 1 to 8 correspond in Tables 1 and 2 to sample numbers S1 to S9 and R1 to R8.

[0133] [Table 1]

[0134] [Table 2]

[0135] Referring to Tables 1 and 2 together, a comparison of Examples 1 to 9 and Comparative Examples 1 to 8 shows that by subjecting the negative electrode material to surface modification treatment by plasma-enhanced chemical vapor deposition and adjusting the mass content ratio of hydrogen element to nitrogen element, sulfur element, and halogen element in the negative electrode material, it is possible to improve the capacity, initial coulombic efficiency, powder conductivity, cycle performance, and rate performance of the negative electrode material.

[0136] Specifically, a comparison between Example 1 and Comparative Example 1 shows that by subjecting the negative electrode material to surface modification treatment by plasma-enhanced chemical vapor deposition and adjusting the mass content ratio of hydrogen element to nitrogen element, sulfur element, and halogen element in the negative electrode material, it is possible to comprehensively improve the capacity, initial coulombic efficiency, powder conductivity, cycle performance, and rate performance of the negative electrode material.

[0137] Comparing Comparative Examples 2 to 8 with Example 2, it is clear that in order to significantly improve the capacity, initial coulombic efficiency, powder conductivity, cycle performance, and rate performance of the negative electrode material, it is necessary to adjust the mass content ratio of hydrogen element to nitrogen element, sulfur element, and halogen element in the negative electrode material within an appropriate range.

[0138] 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 active material and a matrix material, the negative electrode material contains hydrogen, halogen, nitrogen, and sulfur; The mass content of hydrogen element is m H The mass content of the halogen element is m X The mass content of sulfur element is m S The mass content of nitrogen element is m N A negative electrode material characterized in that the following relational expression is satisfied when: 0.02≦m X / m H ≦5.00、 0.02≦m N / m H ≦20.00, and 0.05≦m S / m H ≦5.00。

2. The negative electrode material according to claim 1, wherein at least one of the following (1) to (3) is satisfied: (1) The matrix material is located on at least a portion of the surface of the silicon-based active material. (2) The silicon-based active material is located on the surface of the matrix material. (3) The silicon-based active material and the matrix material are dispersed in each other.

3. The negative electrode material according to claim 1, wherein at least one of the following (1) to (2) is satisfied: (1) The negative electrode material has pores. (2) In the pore volume distribution curve of the negative electrode material, characteristic peaks of pore volume are present within the pore diameter ranges of 240 Å to 280 Å, 290 Å to 320 Å, 340 Å to 390 Å, and 410 Å to 460 Å.

4. The negative electrode material according to claim 1, wherein at least one of the following (1) to (3) is satisfied: (1)50mg / kg≦m X ≦1500mg / kg。 (2)100mg / kg≦m N ≦4000mg / kg。 (3)10mg / kg≦m S ≦200mg / kg。

5. The negative electrode material according to claim 1, wherein at least one of the following (1) to (2) is satisfied: (1) The silicon-based active material includes at least one of elemental silicon, silicon oxide, silicon alloy, and silicate. (2) The silicon-based active material has the general formula: SiO x The silicon oxide includes silicon oxides represented by (0<x≦2).

6. The negative electrode material according to claim 1, wherein at least one of the following (1) to (2) is satisfied: (1) The silicon-based active material contains a doping metal M, which is at least one selected from the group consisting of Li, Mg, Al, Fe, La, Zn, Ti, Cu, and Mn. (2) The silicon-based active material contains a doping metal M, and the mass content of the metal M in the negative electrode material is greater than 0 wt % and less than or equal to 15 wt %.

7. The negative electrode material according to claim 1, wherein at least one of the following (1) to (3) is satisfied: (1) The matrix material includes a carbon material or a mixture of a carbon material and an inorganic oxide. (2) The matrix material includes a carbon material including at least one of graphite, graphene, amorphous carbon, diamond-like carbon, carbon nanotubes, and carbon fibers. (3) The matrix material contains a carbon material, and the carbon material is located on at least a portion of the surface of the silicon-based active material to form a carbon layer, and the carbon layer has a thickness of 20 nm to 1000 nm.

8. 8. The negative electrode material according to claim 7, wherein the mass content of carbon element in the negative electrode material is 0.5 wt % to 15 wt % with respect to the mass of the negative electrode material.

9. 2. The negative electrode material according to claim 1, wherein the median diameter is 2.0 μm to 12.0 μm.

10. Specific surface area is 0.50m 2 / g to 10.00m 2 2. The negative electrode material according to claim 1, wherein the Cr content is 1.0 / g.

11. The tap density is 0.75 g / cm 3 ~1.35g / cm 3 2. The negative electrode material according to claim 1, wherein

12. The negative electrode material according to claim 1, wherein at least one of the following (1) to (3) is satisfied: (1) The powder conductivity of the negative electrode material under a pressure of 20 kN is 0.01 S / cm to 100.00 S / cm. (2) The mass content of water in the negative electrode material is 0.01 wt % to 0.80 wt %. (3) The pH of the negative electrode material is 6.00 to 12.

00.

13. preparing a precursor comprising a silicon-based active material and a matrix material; surface-modifying the precursor by plasma-enhanced chemical vapor deposition in a modified gas source environment to obtain an anode material; A method for producing a negative electrode material comprising: the gas phase reforming source comprises hydrogen, sulfur, nitrogen, and a halogen; In the negative electrode material, the mass content of hydrogen element is m H The mass content of the halogen element is m X The mass content of sulfur element is m S The mass content of nitrogen element is m N A method for producing a negative electrode material, characterized in that the following relational expression is satisfied when: 0.02≦m X / m H ≦5.00、 0.02≦m N / m H ≦20.00, and 0.05≦m S / m H ≦5.00。

14. A secondary battery comprising the anode material according to any one of claims 1 to 12 or the anode material produced by the production method according to claim 13.

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