Negative electrode material and lithium-ion battery

Abstract

A negative electrode material and a lithium-ion battery. The negative electrode material comprises a silicon-based material and a graphite material. The negative electrode material is subjected to a Raman surface scanning test, in which 200 groups of spectra are randomly selected, and the number of spectra having peaks at the position of 500 cm -1 to 520 cm -1 in the Raman spectra of the negative electrode material is set as n; and in the spectra with peaks at the position of 500 cm-1 to 520 cm-1: the peak intensities at the position of 1345 cm-1 to 1355 cm-1 are respectively IA1, IA2…, IAn, and the peak intensities at the position of 1570 cm-1 to 1610 cm-1 are respectively I'A1, I'A2…, I'An. The negative electrode material satisfies the relational expression (I), wherein [formula (II)]. Particles of the negative electrode material have a low morphology difference degree and a high morphology concentration. Batteries prepared by means of using the negative electrode material have a high batch yield and stable batches.

Description

Anode materials and lithium-ion batteries

[0001] This application claims priority to Chinese patent application 202411132627.2, filed on August 19, 2024. The entire contents of the aforementioned Chinese patent application are incorporated herein by reference. Technical Field

[0002] This application relates to the field of lithium-ion battery anode materials technology. More specifically, this application relates to an anode material and a lithium-ion battery. Background Technology

[0003] Anode materials are among the most critical materials in lithium-ion batteries. Currently, commonly used anode materials are typically ordinary carbon materials, whose capacity is nearing its limit. To further improve capacity, other types of anode materials need to be introduced. Silicon-based anode materials have high specific capacity and are already industrialized, but their significant volume expansion limits large-scale application. Currently, silicon-based anode materials are still used in combination with graphite, and the proportion added is not high. To fully utilize the advantages of silicon-graphite anode materials while mitigating their disadvantages, the compatibility of graphite and silicon-based materials and the composite method need to be considered.

[0004] Currently, silicon-based graphite anode materials are mainly simple mixtures of silicon and graphite, failing to leverage their synergistic effects. Silicon is merely used as a simple additive in the graphite system, unable to effectively utilize its superior performance. A better composite method can synergistically leverage the advantages of both graphite and silicon while mitigating their disadvantages. For example, the addition of silicon can compensate for the insufficient capacity of graphite, while the introduction of graphite can buffer the expansion of silicon and extend cycle life. However, the introduction of silicon increases the difficulty of battery manufacturing and can easily lead to a decrease in battery yield.

[0005] Therefore, providing a silicon-based graphite anode material to achieve high yield and stable performance in the fabricated batteries is an urgent problem to be solved. Summary of the Invention

[0006] According to one aspect of this application, a negative electrode material is provided, comprising a silicon-based material and a graphite-based material. Raman surface scanning spectroscopy is used to analyze the negative electrode material, and 200 sets of spectra are randomly selected. Among these 200 sets of spectra, the 500cm² value is... -1 -520cm -1 Let n be the number of spectra with peaks at 500 cm⁻¹. -1 -520cm -1 In the spectrum with a peak: 1345cm -1 -1355cm -1 The peak intensities at I are respectively A1 I A2 , ..., I An1570cm -1 -1610cm -1 The peak intensities at I′ are respectively A1 , I′ A2 , ..., I′ An The negative electrode material satisfies the following relationship:

[0007] in, And A≤0.8.

[0008] According to another aspect of this application, a lithium-ion battery is provided, comprising the negative electrode material of any of the foregoing embodiments.

[0009] The negative electrode material prepared according to the embodiments of this application exhibits low inter-particle morphological variation and high concentration. Batteries fabricated using this negative electrode material show high batch yield and batch stability. Attached Figure Description

[0010] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application are illustrated by way of example and not limitation, and the same or corresponding reference numerals denote the same or corresponding parts, wherein:

[0011] Figure 1 shows a schematic diagram of a battery in a discharged state;

[0012] Figure 2 shows a schematic diagram of the steps in the preparation method of the negative electrode material;

[0013] Figure 3 shows a schematic diagram of the Raman spectrum of the negative electrode material in Example 1. Detailed Implementation

[0014] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0015] It should be understood that the terms "comprising" and "including" used in the specification and claims of this application indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0016] It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this specification and claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this specification and claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations.

[0017] As used in this specification and claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0018] The specific embodiments of this application are described in detail below with reference to the accompanying drawings. Unless otherwise specified, the materials, reagents and equipment used in the embodiments of this application are obtained through conventional commercial channels.

[0019] One embodiment of this application provides a secondary battery (such as a lithium-ion battery, sodium-ion battery, etc.), including a casing, an electrode assembly, and an electrolyte / electrolyte. Both the electrode assembly and the electrolyte / electrolyte are located within the casing.

[0020] The outer casing can be a packaging bag sealed with an encapsulating film (such as aluminum-plastic film), for example, a pouch battery for a secondary battery. In other embodiments, the secondary battery can also be a steel-cased battery, an aluminum-cased battery, etc.

[0021] Figure 1 shows a schematic diagram of a battery in a discharged state, i.e., during operation. As shown, the electrode assembly includes a positive electrode 110, a negative electrode 120, and a separator 130, with the separator disposed between the positive and negative electrode sheets. The electrode assembly can be a stacked structure, formed by alternating layers of the positive electrode, separator, and negative electrode. In other embodiments, the electrode assembly can also be a wound structure, formed by winding the positive electrode, separator, and negative electrode after they have been stacked in sequence.

[0022] Positive electrode film

[0023] The positive electrode 110 includes a positive current collector 111 and a positive active layer 112 disposed on at least one surface of the positive current collector. The positive current collector can be aluminum foil or nickel foil, or any composite current collector disclosed in the prior art, such as, but not limited to, current collectors formed by combining the aforementioned conductive foil and polymer substrate. The positive active layer contains a positive active material, which includes compounds that reversibly insert and extract metal ions. In some embodiments, the positive active material may include lithium transition metal composite oxides, sodium transition metal composite oxides, etc. The lithium transition metal composite oxide contains lithium and at least one element selected from cobalt, manganese, and nickel. In some embodiments, the positive active material may include, but is not limited to, lithium cobalt oxide (LiCoO2), lithium nickel manganese cobalt ternary materials (NCM), lithium manganese oxide (LiMn2O4), and lithium nickel manganese oxide (LiNi). 0.5 Mn 1.5 At least one of lithium iron phosphate (LiFePO4) or lithium iron phosphate (LiFePO4).

[0024] negative electrode sheet

[0025] The negative electrode 120 includes a negative electrode current collector 121 and a negative electrode active material layer 122 disposed on at least one surface of the negative electrode current collector. The negative electrode current collector can be at least one of copper foil, nickel foil, stainless steel foil, titanium foil, or carbon-based current collectors, or any composite current collector disclosed in the prior art, such as, but not limited to, current collectors formed by combining the aforementioned conductive foil and polymer substrate. The negative electrode active material layer includes a negative electrode material.

[0026] During battery operation, i.e. when the battery is in a discharge state, metal ions 140 (e.g., lithium ions) in the negative electrode are released from the lattice of the negative electrode material, pass through the electrolyte / electrolyte through the separator 130, and are embedded in the lattice of the positive electrode material.

[0027] Conversely, when the battery is charged by applying an external circuit, the oxidation of the positive electrode material causes metal ions (such as lithium ions) in the positive electrode to be released from the lattice of the positive electrode material, pass through the electrolyte / electrolyte through the separator, and move to the negative electrode; at the same time, the negative electrode material undergoes a reduction reaction, causing metal ions to be embedded in the lattice of the negative electrode material.

[0028] As metal ions move back and forth between the positive and negative electrodes, the battery can achieve the discharge and charge process in thousands of cycles.

[0029] The performance of anode materials containing silicon-based materials and graphite is mainly affected by the performance of graphite and silicon-based materials. There are both interference and synergistic effects between silicon-based materials and graphite. Only by maximizing the positive synergistic effect between silicon-based materials and graphite, while suppressing their negative interference effects, can anode materials containing silicon-based materials and graphite exhibit good electrochemical performance.

[0030] This application provides a negative electrode material comprising silicon-based materials and graphite-based materials. Raman surface scanning was used to analyze the negative electrode material, and 200 sets of spectra were randomly selected. Among these 200 sets of spectra, the 500cm² value was... -1 -520cm -1 Let n be the number of spectra with peaks at 500 cm⁻¹. -1 -520cm -1 In the spectrum with a peak: 1345cm -1 -1355cm -1 The peak intensities at I are respectively A1 I A2 , ..., I An 1570cm -1 -1610cm -1 The peak intensities at I′ are respectively A1 , I′ A2 , ..., I′ An The negative electrode material satisfies the following relationship:

[0031] in, And A≤0.8.

[0032] Batteries made from anode materials containing silicon-based materials and graphite are prone to capacity and first-efficiency fluctuations, which the inventors speculate is related to the large differences in particle surface morphology of the anode materials. Through extensive experimental research and verification, the inventors discovered that by limiting the degree of particle morphology difference in anode materials containing silicon-based and graphite materials to a certain range, the yield of lithium-ion batteries can be effectively improved. Raman surface scanning can characterize the surface properties of anode materials. Therefore, in the embodiments of this application, Raman surface scanning can be used to determine / characterize the particle surface morphology differences of anode materials containing silicon-based and graphite materials, thereby providing anode materials capable of producing batteries with high yield and stable performance.

[0033] In the Raman spectrum of the negative electrode material in this application, 500 cm⁻¹ -1 -520cm -1 The peak at 500 cm⁻¹ can be used to characterize the resonant vibration peaks between Si-Si atoms. Its peak intensity and shape can reflect the crystal structure and impurity content of the active material in silicon-based materials. -1 -520cm -1 The presence of a peak at 1345cm indicates that the negative electrode material contains silicon-based materials. -1 -1355cm -1 The peak at 1570 cm⁻¹ (also known as the D peak) reflects the disordered structure of carbon materials (amorphous carbon materials). -1 -1610cm -1 The peak at that point (also known as the G peak) corresponds to the plane vibration mode of graphite, representing SP.2 The bond (planar structure) reflects the ordered structure of carbon materials (i.e., graphitized carbon materials). The K value in the above formula refers to the ratio of the peak intensity of the D peak to the G peak in the spectrum of silicon-based materials detected in the negative electrode material. D / I G The average value. In the above formula, A represents the variance of the ratio of the peak intensities of the D peak to the G peak in the Raman spectrum of silicon-based materials. By statistically analyzing the I values ​​in the Raman spectra of various silicon-based anode materials... Ai / I ′Ai The difference from the mean (e.g., variance) is used to measure the morphological differences between particles in an anode material. A smaller variance (A) indicates that the morphologies of the particles are more similar. Batteries made from this type of anode material have higher yields and more stable performance.

[0034] Specifically, in Raman spectra, at 500 cm⁻¹ -1 -520cm -1 When the peak intensity of the spectrum meets the numerical range of the above relationship, the morphological difference between the particles of the negative electrode material is low, the concentration is high, and the batch yield of the manufactured batteries is high and the batch is stable. The higher the morphological concentration between the particles, the higher the consistency of the reaction between the surface of the negative electrode material particles and the electrolyte after the battery is manufactured. That is, the closer the thickness and composition of the solid electrolyte interphase (SEI) layer generated on the surface of different negative electrode material particles during the battery formation and capacity testing, the smaller the difference. The capacity and efficiency of the battery made from the negative electrode material are more concentrated, the battery consistency is higher, and the battery yield is higher.

[0035] When the value of the above relationship is greater than 0.8, it indicates that the morphology concentration between particles in the negative electrode material is low, the morphology is diverse and dispersed, and the SEI content, morphology and thickness generated during the formation and capacity separation process are different, resulting in large fluctuations in the capacity and efficiency of the battery made from the negative electrode material and low battery yield.

[0036] Furthermore, in some implementations, when the above relationship is less than 0.01, more processes and costs are required, which is not conducive to the industrialization of anode material products and the realization of their commercial value.

[0037] In some embodiments, the value of A can be 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or any value within the range of any two of the above values. For example, the value of A can be 0.01≤A≤0.5, or 0.1≤A≤0.6, or 0.01≤A≤0.3, or 0.2≤A≤0.5, or 0.4≤A≤0.7, or 0.6≤A≤0.8.

[0038] In some embodiments, the negative electrode material satisfies the relationship: B=(|I A1 / I′ A1 -K|+|I A2 / I′ A2 -K|+…+|I An / I′ An -K|) / n, and 0<B≤0.3. This relationship can be further used to characterize the surface morphology concentration between particles in the negative electrode material from another perspective. This relationship represents the average deviation of the ratio of the peak intensities of the D peak and the G peak in the Raman spectrum of each silicon-based negative electrode material from the average value K, that is, the absolute deviation of the mean. When the concentration meets the range of the above relationship, the morphology concentration between particles in the negative electrode material is high, the produced battery has good consistency and high yield. When the absolute value of the concentration is greater than 0.3, it indicates that the surface morphology between particles in the negative electrode material is relatively dispersed and diverse. The SEI content, morphology and thickness generated during the formation and capacity testing processes are different, resulting in large fluctuations in battery capacity and efficiency, and low battery yield.

[0039] In some embodiments, the value of B can be 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, or any value within the range of any two of the above values. For example, the value of B can be 0.01≤B≤0.2, or 0.01≤B≤0.1, or 0.05≤B≤0.25, or 0.15≤B≤0.3.

[0040] In some embodiments, the specific surface area of ​​the negative electrode material is <3.0 m². 2 / g, for example, can be 2.9m 2 / g, 2.8m 2 / g, 2.7m 2 / g, 2.6m 2 / g, 2.5m 2 / g, 2.4m 2 / g, 2.3m 2 / g, 2.0m 2 / g, 1.5m 2 / g, 1.0m 2 / g, etc., and of course, other values ​​within the above range are also possible. When the specific surface area falls within the above range, it indicates that the surface morphology of the negative electrode material is concentrated, not dispersed or disordered, and the SEI content, morphology, and thickness generated during the formation and capacity grading processes are uniform, resulting in small fluctuations in battery capacity and efficiency, and high battery yield.

[0041] In some embodiments, the moisture content of the negative electrode material is <0.5% by mass. Exemplary values ​​can be 0.49%, 0.48%, 0.47%, 0.46%, 0.45%, 0.40%, 0.35%, 0.30%, 0.25%, 0.20%, 0.15%, 0.10%, etc., and other values ​​within the above range are also possible. When the moisture content falls within the above range, it indicates that the surface morphology of the negative electrode material is concentrated, not dispersed or disordered. The SEI content, morphology, and thickness generated during the formation and capacity testing processes are uniform, resulting in small fluctuations in battery capacity and efficiency, and a high battery yield.

[0042] In some embodiments, the volumetric particle size distribution D10 in the negative electrode material is greater than 1.0 μm. Exemplary values ​​include 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, and 2.0 μm, and other values ​​within the above range are also possible. When the volumetric particle size distribution D10 falls within the above range, it indicates that the surface morphology of the negative electrode material is concentrated, not dispersed or disordered, and the SEI content, morphology, and thickness generated during formation and capacity testing are uniform, resulting in small fluctuations in battery capacity and efficiency, and high battery yield. The particle size testing method refers to GB / T 19077-2016. The cumulative particle size distribution of the negative electrode material is measured using a Malvern laser particle size analyzer (Mastersizer 3000) and laser diffraction. D10 represents the particle size corresponding to a cumulative particle size distribution percentage of 10%.

[0043] In some embodiments, based on 100wt% of the negative electrode material, the carbon content is 5wt% to 95wt%, and the silicon content is 5wt% to 95%. Exemplarily, the carbon content can be 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 60wt%, 70wt%, 80wt%, 90wt%, 95wt%, etc., or other values ​​within the aforementioned range. Similarly, exemplarily, the silicon content can be 95wt%, 90wt%, 85wt%, 80wt%, 75wt%, 70wt%, 65wt%, 60wt%, 55wt%, 50wt%, 40wt%, 30wt%, 20wt%, 10wt%, 5wt%, etc., or other values ​​within the aforementioned range.

[0044] In some embodiments, the gas production rate of the battery made of negative electrode material during the aging process is <0.01 mL / Ah. Exemplary values ​​can be 0.009 mL / Ah, 0.008 mL / Ah, 0.007 mL / Ah, 0.006 mL / Ah, 0.005 mL / Ah, 0.004 mL / Ah, 0.003 mL / Ah, 0.002 mL / Ah, 0.001 mL / Ah, etc., and of course, other values ​​within the above range are also possible.

[0045] In some embodiments, a battery made of negative electrode material, after being stored at 60°C for 15 days, produces less than 0.1 mL / Ah of gas. Exemplary values ​​could be 0.09 mL / Ah, 0.08 mL / Ah, 0.07 mL / Ah, 0.06 mL / Ah, 0.05 mL / Ah, 0.04 mL / Ah, 0.03 mL / Ah, 0.02 mL / Ah, 0.01 mL / Ah, etc., or other values ​​within the above range.

[0046] In some embodiments, the 500 cm⁻¹ Raman spectrum of the negative electrode material -1 -520cm -1 The ratio of the number of spectra with peaks to the number of spectra without peaks is 0.05-40, with examples including 0.05, 0.1, 0.5, 1, 5, 10, 15, 20, 25, 30, 35, and 40, or other values ​​within the above range. This ratio can also characterize the proportion of silicon in the product from another perspective.

[0047] In some embodiments, the silicon-based material in the negative electrode material may include at least one of amorphous silicon, crystalline silicon, silicon oxide, and silicate.

[0048] In some embodiments, the silicon-based material includes silicon oxide, which includes silicon and oxygen elements in an atomic ratio of 0 to 2, excluding 0.

[0049] In some embodiments, the silicon-based material includes silicon oxide, which has the general chemical formula SiOx, where 0 < x ≤ 2. Specifically, SiOx can be SiO 0.5 SiO 0.7 SiO 0.9 SiO, SiO 1.2 SiO 1.5 SiO 1.8 SiO 1.9 etc. are not specified here.

[0050] Silicon oxides can be represented by the general formula SiOx (0 < x ≤ 2). They can be materials formed by silicon dispersed in SiO2; or they can be materials with tetrahedral structural units, where silicon atoms are located at the center of the tetrahedral structural units, and oxygen atoms and / or silicon atoms are located at the four vertices of the tetrahedral structural units.

[0051] In some embodiments, the graphite material in the negative electrode material may include at least one of natural graphite, artificial graphite, expanded graphite, and graphite oxide.

[0052] In some embodiments, the negative electrode material includes a carbon material, which includes at least one of amorphous carbon and graphitized carbon.

[0053] The negative electrode material provided in this application is a composite material comprising silicon-based materials and graphite-based materials. The specific composite form can be diverse; for example, it can be a core composed of silicon-based materials and graphite-based materials, with a carbon coating layer on the core surface; or it can be silicon-based materials and graphite-based materials dispersed together, each with a carbon coating layer on its surface. This excellent composite method can synergistically leverage the advantages of both silicon-based and graphite-based materials. Batteries prepared using this negative electrode material exhibit high yield and good stability.

[0054] According to one aspect of this application, a method for preparing a negative electrode material is provided. Figure 2 shows a schematic diagram of exemplary steps of the method for preparing a negative electrode material according to some embodiments of this application.

[0055] As shown in the figure, the preparation method of the negative electrode material includes: Step S1, preparing silicon-based material: taking silicon-oxygen raw material with a carbon layer on its surface, and subjecting the surface of the silicon-oxygen raw material to plasma modification treatment by introducing a non-polymerizable gas under vacuum conditions to a pressure less than 0.1 MPa. The plasma modification treatment temperature is 30℃~180℃, the plasma modification treatment time is 10s-150s, the median particle size of the silicon-oxygen raw material is 2μm~20μm, and the plasma modification treatment pressure range is 50Pa~150Pa, thus obtaining the silicon-based material; Step S2, preparing a suspension containing silicon-based material and graphite: uniformly dispersing the silicon-based material in a dispersant. Graphite is gradually added and stirred to disperse, resulting in a suspension containing silicon-based materials and graphite. The D50 of the silicon-based material particles is 2μm to 20μm, and the D50 of the graphite particles is 6μm to 20μm. The mass content of the silicon-based material in the suspension containing silicon-based materials and graphite is 5wt% to 95wt%. The mass content of graphite in the suspension containing silicon-based materials and graphite is 5wt% to 95wt%. In the third step S3, the negative electrode material is prepared by mixing the suspension containing silicon-based materials and graphite with a binder precursor at a mass ratio of 0.01% to 3% relative to the dry components of the suspension (i.e., silicon-based materials and graphite). After separating the solvent, the mixture is dried to obtain the negative electrode material.

[0056] The method for preparing the negative electrode material in this application involves modifying silicon-oxygen raw materials using a plasma method, then dispersing them together with graphite in a solvent to form a uniform suspension. A binder is then added, and the solvent is separated to obtain the negative electrode material. This process results in low morphological variation among the particles, high concentration, and a non-dispersed, non-randomized structure, thus meeting the requirements. The anode material exhibits uniform SEI content, morphology, and thickness during formation and capacity testing, resulting in minimal capacity and efficiency fluctuations and high battery yield in batteries containing this material. It should be noted that in the second step, the mass content of silicon-based material or graphite in the suspension containing silicon-based material and graphite refers to the percentage of silicon-based material or graphite relative to the sum of the masses of silicon-based material and graphite in the suspension. In the third step, the ratio of the mass of the binder precursor to the sum of the masses of silicon-based material and graphite in the suspension is 0.01%-3%.

[0057] Specifically, in the first step, 200-1000g of silicon-oxygen raw material with a carbon layer on its surface is placed in a low-temperature plasma device. After the vacuum is drawn to a pressure of less than 0.1MPa, a non-polymerizable gas is introduced to perform plasma modification treatment on the surface of the silicon-oxygen raw material particles.

[0058] Placing silicon-oxygen raw materials in a plasma device for modification can adjust their surface morphology. Plasma modification helps to uniformly coat the surface of silicon-oxygen raw material particles with a carbon layer, while controlling the deposition rate and thickness of the carbon layer on the graphite and silicon-oxygen raw material surfaces, thus adjusting the morphology concentration between particles.

[0059] In some embodiments, the silicon-oxygen raw material includes silicon oxide SiOy, where 0 < y ≤ 2. The silicon oxide is a silicon-oxygen complex containing oxygen atoms and silicon atoms, with a molar ratio of oxygen atoms to silicon atoms of 0 to 2, excluding 0. It can be Si or SiO. 0.2 SiO 0.5 SiO 0.8 SiO, SiO 1.2 SiO 1.5 SiO 1.8 It can be a substance composed of two or more of the following: SiO2, or a compound with the chemical formula SiOy. Of course, y can also be other values ​​within the above range, which are not limited in this application.

[0060] The modification results are related to temperature, pressure, time, etc.

[0061] In some embodiments, the pressure range of the plasma modification treatment in the first step is 50 Pa to 150 Pa. Exemplary values ​​can be 50 Pa, 60 Pa, 70 Pa, 80 Pa, 90 Pa, 100 Pa, 110 Pa, 120 Pa, 130 Pa, 140 Pa, 150 Pa, etc., and of course, other values ​​within the above range are also possible.

[0062] In some implementations, the plasma modification treatment time in the first step is 10s-150s, and exemplary values ​​can be 10s, 20s, 30s, 40s, 50s, 60s, 70s, 80s, 90s, 100s, 110s, 120s, 130s, 140s, 150s, etc., or other values ​​within the above range.

[0063] In some embodiments, the non-polymerizable gas in the first step includes at least one of hydrogen, argon, helium, nitrogen, krypton, and neon. Other non-polymerizable gases refer to gases that cannot undergo polymerization themselves.

[0064] In some embodiments, the silicon-based material includes at least one of amorphous silicon, crystalline silicon, silicon oxide, and silicate.

[0065] In some embodiments, the median particle size, D50, of the silicon-based material is 2μm to 20μm, and exemplary values ​​can be 2μm, 4μm, 6μm, 8μm, 10μm, 12μm, 14μm, 16μm, 18μm, 20μm, etc., or other values ​​within the above range. The particle size testing method refers to GB / T 19077-2016. The volumetric cumulative particle size distribution of the negative electrode material is determined by measuring the particle size distribution using a Malvern laser particle size analyzer (Mastersizer 3000) and laser diffraction. D50 represents the particle size corresponding to a cumulative particle size distribution percentage of 50%.

[0066] Specifically, in the second step, the silicon-based material obtained in the first step is uniformly dispersed in a dispersant, and then graphite is gradually added. After stirring and dispersing at a speed of 300-1000 rpm for 1-4 hours, a suspension containing silicon-based material and graphite is obtained.

[0067] The dispersant contains one or a mixture of two or more of the following: deionized water, ethanol, propanol, isopropanol, propane, DFM, and acetone.

[0068] Graphite includes at least one of natural graphite, artificial graphite, expanded graphite, and graphite oxide. The Dv50 of the graphite particles is between 6μm and 20μm, and exemplary values ​​can be 6μm, 8μm, 10μm, 12μm, 14μm, 16μm, 18μm, 20μm, etc., or other values ​​within the above range.

[0069] Silicon-based materials account for 5 wt% to 95 wt% of the total mass of silicon-based materials and graphite. Specifically, silicon-based materials account for 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%, 95 wt% of the total mass of silicon-based materials and graphite, or other values ​​within the above range.

[0070] Graphite comprises 5 wt% to 95 wt% of the total mass of silicon-based materials and graphite. Specifically, graphite comprises 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%, 95 wt% of the total mass of silicon-based materials and graphite, or other values ​​within the above range.

[0071] By employing a liquid-phase dispersion method, silicon-based materials are first dispersed in a solution, and then graphite is added in batches. This helps to improve the uniformity of dispersion of silicon-based materials and graphite, and further reduces particle agglomeration.

[0072] Specifically, in the third step, the suspension containing silicon-based materials and graphite is transferred to a three-necked flask, 0.01%-3% of a binder precursor is added, and the stirring speed is set to 50rpm-300rpm.

[0073] The molecular structure of the adhesive precursor contains at least one of the functional groups of amino, carboxyl, cyano, and hydroxyl. The number-average molecular weight of the adhesive precursor is 2,000-1,000,000. The viscosity of the adhesive precursor at a solid content of 3% is 1,000 Pa·s-100,000 mPa·s.

[0074] In some embodiments of this application, the mass ratio of the binder precursor to the total mass of silicon-based materials and graphite in the suspension containing silicon-based materials and graphite is 0.01%-3%, specifically 0.01%, 0.05%, 0.1%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, etc., or other values ​​within the above range.

[0075] After the suspension containing silicon-based materials and graphite is mixed evenly with the binder precursor, heating is started while stirring is maintained during heating. When the temperature reaches 50℃-120℃, the vacuum pump is turned on to maintain the vacuum degree in the three-necked flask below 0.1MPa. After reacting for 4-12 hours, reflux condensation is started to separate the solvent from the mixed solution after the reaction. Then, the remaining material in the three-necked flask is placed in a vacuum oven and dried below 80℃ to obtain the negative electrode material.

[0076] Adding a small amount of binder precursor to the mixed suspension containing silicon-based materials and graphite, followed by drying, can reduce the re-agglomeration of silicon-based materials and graphite during the slurry preparation process, thus reducing uneven component distribution. On the other hand, it can also perform secondary adjustments to the surface of silicon-based materials and graphite, further improving the concentration of their morphology and increasing the yield of battery fabrication.

[0077] Optionally or additionally, in some embodiments, the negative electrode material obtained in the foregoing steps may be dispersed and sieved using a vibrating chamber (VC) high-efficiency mixer.

[0078] The negative electrode material prepared according to the preparation method of the present application can be applied to lithium-ion batteries. It is a composite material of silicon and graphite, and its good composite method can synergistically bring out the advantages of graphite and silicon materials.

[0079] According to another aspect of this application, a lithium-ion battery is provided, comprising the aforementioned negative electrode material or a negative electrode material prepared according to the aforementioned preparation method.

[0080] Example 1

[0081] Step 1: Take 50g of silicon-oxygen particles (SiO core, carbon coating on surface) (D50 = 6μm) (commercially available) and place them in the material chamber of a low-temperature plasma device. Evacuate to an internal pressure of 0.02MPa, heat to 130℃, and then... (The sentence is incomplete and requires more context to translate accurately.) 3 Hydrogen gas was introduced at a rate of / min, and after 60s of treatment, the temperature was lowered to 25℃. The sample was then removed to obtain silicon-based material.

[0082] Step 2: Take 50g of silicon-based material (D50 = 6μm) and add it to 200g of isopropanol solvent. Disperse at 200rpm for 1 hour. Then add 450g of graphite (commercially available) and continue stirring and dispersing for another hour to obtain a silicon-oxygen-graphite suspension. The mass content of silicon-based material in the suspension is 10wt%, and the mass content of graphite is 90wt%.

[0083] Step 3: Transfer the silicon-oxygen-graphite suspension to a three-necked flask, add 1% (by mass relative to the total amount of silicon-based material and graphite) of polyacrylic acid with a number average molecular weight of 2000-1000000 (i.e., polyacrylic acid precursor), and set the stirrer speed to 100 rpm. Turn on the heater, and when the temperature reaches 80°C, turn on the vacuum pump and maintain the vacuum at 0.1 MPa for 6 hours. Then, start the reflux condenser to separate the solvent from the solution. Finally, place the remaining material in a vacuum oven and dry it below 80°C to obtain the negative electrode material.

[0084] Finally, the negative electrode material is broken down and sieved using a VC high-efficiency mixer to obtain a negative electrode material in powder form.

[0085] Figure 3 shows a schematic diagram of the Raman spectrum of the negative electrode material in Example 1.

[0086] As shown in Figure 3, the spectrum is selected in the range of 500-520 cm. -1 The spectrum shows peaks at 1345-1355 cm⁻¹. -1 Peak intensity at I A1 I A2 , ..., I An 1570-1610cm -1 Peak intensity I′ at A1 , I′ A2 , ..., I′ An Substitute the values ​​into the relational expression for calculation.

[0087] Example 2

[0088] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0089] The difference is that the modification temperature of the silicon-oxygen particles is 50℃ and the modification time is 120s.

[0090] Example 3

[0091] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0092] The difference lies in the modification temperature of the silica particles being 50℃ and the amount of the binder precursor being 3%.

[0093] Example 4

[0094] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0095] The difference is that the modification time of the silica particles is 140s, and the amount of the binder precursor is 3%.

[0096] Example 5

[0097] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0098] The difference is that the pressure in step 1 is 50 Pa, and the amount of adhesive precursor used in step 3 is 0.01%.

[0099] Example 6

[0100] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0101] The difference is that the pressure in step 1 is 150 Pa, and the amount of adhesive precursor used in step 3 is 1%.

[0102] Example 7

[0103] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0104] The difference lies in the amount of the adhesive precursor used: 0.01%.

[0105] Example 8

[0106] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0107] The difference is that the D50 of the silicon oxide particles is 18 μm.

[0108] Example 9

[0109] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0110] The difference is that the D50 of graphite particles is 18 μm.

[0111] Example 10

[0112] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0113] The difference is that the silicon-based material content in the suspension is 30 wt%, while the graphite content is 70 wt%.

[0114] Example 11

[0115] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0116] The difference is that the D50 of the silicon oxide particles is 9μm.

[0117] Comparative Example 1

[0118] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0119] The differences are: the modification time of silicon oxide particles is 300s, the amount of binder precursor is 4%, and the temperature in the three-necked flask is 100℃.

[0120] Comparative Example 2

[0121] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0122] The difference is that the pressure in step 1 is 0.18 MPa.

[0123] Comparative Example 3

[0124] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0125] The difference is that the modification temperature of silicon-oxygen particles is 20℃.

[0126] Comparative Example 4

[0127] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0128] The difference is that the modification temperature of silicon-oxygen particles is 250℃.

[0129] Comparative Example 5

[0130] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0131] The difference is that the modification time for silicon-oxygen particles is 5 seconds.

[0132] Comparative Example 6

[0133] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0134] The difference is that the modification time for silicon-oxygen particles is 200 seconds.

[0135] Comparative Example 7

[0136] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0137] The difference is that the D50 of the silicon oxide particles is 21 μm.

[0138] Comparative Example 8

[0139] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0140] The difference is that the D50 of the silicon oxide particles is 1.5 μm.

[0141] Comparative Example 9

[0142] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0143] The difference is that the D50 of graphite particles is 25μm.

[0144] Comparative Example 10

[0145] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0146] The difference is that the D50 of graphite particles is 5μm.

[0147] Comparative Example 11

[0148] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0149] The difference is that the silicon-based material content in the suspension is 4 wt%, while the graphite content is 96 wt%.

[0150] Comparative Example 12

[0151] The preparation process of the negative electrode material is basically the same as that in Example 1.

[0152] The difference is that the suspension contains 96 wt% silicon-based material and 4 wt% graphite.

[0153] Raman surface scanning tests were performed on the negative electrode materials of Examples 1 to 11 and Comparative Examples 1 to 12. 200 spectra were randomly selected, and the spectra values ​​that met the conditions were substituted into the relational formula: The calculated value is A, also known as variance.

[0154] B = (|I A1 / I′ A1 -K|+|I A2 / I′ A2 -K|+…+|I An / I′ An -K|) / n, the calculated value is B, also known as absolute deviation.

[0155] The specific surface area was tested as C, the moisture content as D, the volume distribution of particle size as D10, the carbon content and silicon content in the negative electrode material, the gas production during the aging process of the battery made with the negative electrode material, the gas production during high-temperature storage, and the battery yield as E.

[0156] The testing method is as follows:

[0157] 1. Raman surface scanning test method

[0158] The Raman spectra of the powder were tested using a Renishaw In Via microconfocal Raman spectrometer (Japan). The test parameters were: laser wavelength 532 nm, test range 120 μm × 120 μm, step size 4 μm. The raw data were processed using the instrument's built-in software. The processing steps included fluorescence removal, baseline removal, peak calibration, and data fitting, followed by peak intensity determination. It is noted that baseline removal was performed with the processed baseline near 0 as the standard. All other processing steps used the initial parameters of the software. Following the aforementioned testing method, 961 tests were required, resulting in 961 sets of data. 200 sets of data were randomly selected for analysis. (500 cm⁻¹) -1 -520cm -1 The method for determining the presence of peaks in a spectrum is that when the peak intensity within this range is higher than 100, it is considered to have a peak.

[0159] 2. Specific surface area testing method

[0160] The specific surface area of ​​the negative electrode material was determined using the gas adsorption BET method. A TriStar 3000 & 3020 specific surface area and pore size analyzer (USA) was used to test the specific surface area of ​​the powder samples. First, an empty specific surface area and pore size analyzer tube, dried at high temperature, was weighed (M1). A certain amount of sample (1 / 2 to 2 / 3 of the tube volume) was then added, and the tube was degassed at 300℃ for one hour. After cooling, the tube weight (M2) was measured; the sample mass is M2-M1. The sample mass was entered into the computer, and the instrument was used for testing. The instrument automatically completed the test, read the data, and recorded the results. It is important to note that after heating the sample to 300℃ and purging with nitrogen for 1 hour, it was cooled to room temperature, and the cooling process still required nitrogen purging.

[0161] 3. Moisture content test method

[0162] Moisture content was determined according to the Karl Fischer method. A Mettler Toledo coulometric moisture analyzer was used for the test. ① Sample amount: 0.5g~1.0g. ② Sample preparation: Place a clean sample vial on the analytical balance and zero it. Then add the sample to the vial, record the sample weight, seal it with special aluminum foil, and cover it with a plastic cap. ③ Sample testing: Place the sealed sample vial in the cassette furnace of the moisture analyzer and heat it at 200℃ to convert the moisture in the sample into water vapor, which is then carried into the analytical cell of the moisture analyzer by the drying carrier gas for testing. ④ Recording results: Read the data and record the test results, accurate to 0.001%.

[0163] 4. Particle size testing methods

[0164] The Malvern 3000 laser particle size analyzer was used for testing. ① Instrument parameter settings: pump speed 2400-2500 r / min; ultrasonic power 20%; timed ultrasonication 1 minute 10 seconds; refractive index 2.42, absorptivity 1. ② Sample preparation: Add 2 mL of anhydrous ethanol to a 50 mL beaker, stir to moisten, then add pure water to about 3 / 4 of the volume (about 40 mL), stir evenly, scrape off the floating matter on the surface, sonicate for 1 minute, and then test. Take 0.5 g of the test sample. ③ Sample testing: After stirring the sample evenly, quickly pour it into the test beaker. At this time, the light blocking degree should be 8%-12%. Start ultrasonication, and click to measure the sample after 10 seconds to obtain the test results.

[0165] 5. Battery yield calculation method after capacity testing

[0166] Prepare the negative electrode sheet according to the formula of negative electrode material: binder: conductive agent = 95.1:3.4:1.5. Select the high-nickel NMC product (hereinafter referred to as NMC) for the positive electrode, and prepare the positive electrode sheet according to the formula of NMC: binder: conductive agent = 96.6:1.4:2.0. Then wind the positive and negative electrode sheets to make a soft-pack battery cell (length 55 mm, width 40 mm, thickness 6.5 mm). After the battery cell undergoes aging, liquid injection, formation, and grading, a soft-pack battery is formed. The battery design parameters are: the positive electrode is compacted at 3.4 g / cc, the negative electrode is compacted at 1.65 g / cc, and the negative electrode surface density is 200 g / m 2 , and the N / P ratio is designed to be 8.2%. Make 100 batteries for each batch. Compare the grading capacity of each battery with the designed capacity. When -0.5% ≤ (actual grading capacity - designed capacity) / designed capacity ≤ 0.5% and the battery appearance is clean, without cracks, deformation, leakage, etc., it is judged as a qualified product. The yield rate = the number of qualified batteries / the total number of batteries.

[0167] 6. Test method for carbon element content

[0168] Use an infrared carbon-sulfur analyzer to test the carbon element content. Instrument name and model: Bruker G4 ICARUS HF from Germany. Test method: Weigh a certain amount of sample and put it into a ceramic crucible, add a fluxing agent, and enter the high-frequency furnace to burn with high-purity oxygen to generate carbon dioxide and sulfur dioxide. The carbon and sulfur element contents in the gas are directly measured by an infrared detector.

[0169] 7. Test method for silicon element content

[0170] Use the ignition method to test the silicon element content. Test instrument: Weigh 1.0000 g - 1.2000 g (denoted as m0) of the sample into a corundum crucible, accurate to 0.1 mg, and weigh 2 parallel samples for each sample. Place the sample in a muffle furnace for heat treatment, and weigh the weight of the product after heat treatment as m1. The silicon element content is calculated using the following formula.

[0171] Muffle furnace model: Sigma (Shanghai) High Temperature Electric Furnace Co., Ltd., model: SGM110 / 14A. Heat treatment conditions: Start from room temperature, rise to 400 °C in 30 minutes, and stay at 400 °C for 60 minutes, then rise to 900 °C in 60 minutes, and stay at 900 °C for 120 minutes, then rise to 1100 °C in 30 minutes, and stay at 1100 °C for 480 minutes, and then cool down to room temperature.

[0172] 8. Gas production test during the battery aging process

[0173] The negative electrode sheet was prepared according to the formula of negative electrode material: binder: conductive agent = 95.1:3.4:1.5. The positive electrode was made of high-nickel NMC product (hereinafter referred to as NMC) and prepared according to the formula of NMC: binder: conductive agent = 96.6:1.4:2.0. Then, the positive and negative electrode sheets were wound to form a soft-pack battery cell (55 mm long, 40 mm wide, and 6.5 mm thick). After the battery cell underwent aging (aging conditions: 300 kg pressure, static at 45℃ for 24 h), the weight of the battery was tested as m1. The battery was placed in a gas generating device to test the mass m2. The buoyancy force F generated by the gas in the battery was calculated as F = (m1-m2)g. According to Archimedes' principle F = ρgV, V was calculated as the total gas generation of the battery. Then, the gas generation per ampere-hour was converted to G = V / Q, where V is the total gas generation of the battery and Q is the battery capacity.

[0174] 9. Gas generation test during high-temperature storage

[0175] The negative electrode sheet was prepared according to a formulation of negative electrode material: binder: conductive agent = 95.1:3.4:1.5. The positive electrode was prepared using high-nickel NMC (hereinafter referred to as NMC) according to a formulation of NMC: binder: conductive agent = 96.6:1.4:2.0. The positive and negative electrode sheets were then wound together to form a soft-pack battery cell (55 mm long, 40 mm wide, and 6.5 mm thick). After aging, electrolyte injection, formation, and capacity testing, the cell formed a soft-pack battery. The battery design parameters are: positive electrode compaction 3.4 g / cc, negative electrode compaction 1.65 g / cc, and negative electrode areal density 200 g / m³. 2 The N / P ratio is designed to be 8.2%. The gas production G1 of the cell after capacity grading is tested, and then the cell is charged to 100% SOC at a rate of 0.5C. It is then stored in a 60℃ constant temperature chamber for 15 days, cooled to room temperature, and the gas production G2 is tested again. The gas production G' during the battery storage process is G' = G2 - G1.

[0176] The weight of the test battery is m1. The battery is placed in the gas generating device to test its mass m2. The buoyancy force generated by the gas in the battery is calculated as F = (m1-m2)g. According to Archimedes' principle F = ρgV, V is the total gas production of the battery. Then, the gas production per ampere-hour is converted to G = V / Q, where V is the total gas production of the battery and Q is the battery capacity.

[0177] Table 1 shows the preparation process parameters for each embodiment and comparative example.

[0178] Table 1

[0179] Table 2 shows the test results for each embodiment and comparative example.

[0180] Table 2

[0181] As shown in Table 2, by controlling the variance A value, i.e., the I value in the spectrum of silicon-based materials, Ai / I ′Ai The variance (difference from the mean) can control the morphological differences between particles in the anode material. The smaller the variance, the more similar the particle morphology. Batteries made from this anode material have higher yield and more stable performance.

[0182] Compared to Example 1, Example 2, with a lower modification temperature but a longer modification time, effectively adjusts the surface morphology of the silicon oxide particles, resulting in higher morphology concentration between particles and a smaller A value.

[0183] Compared to Example 1, Example 3 involves a lower modification temperature, resulting in less surface morphology adjustment of the silicon oxide particles. Furthermore, the content of the binder precursor is higher, leading to a smaller morphology concentration between particles and a larger A value.

[0184] Compared to Example 1, Example 4 has a longer modification time, so the modification treatment can fully adjust the surface morphology of the silicon oxide particles. However, the content of the binder precursor is higher, so the morphology concentration between particles is slightly higher and the A value is slightly larger.

[0185] Compared to Example 1, Comparative Example 1 had a longer modification time and a higher content of binder precursor, resulting in a less concentrated particle morphology and a large A value. The SEI content, morphology, and thickness generated during the formation and capacity separation processes were inconsistent, leading to large fluctuations in the capacity and efficiency of the battery made from the negative electrode material and a low battery yield.

[0186] The negative electrode material prepared according to the embodiments of this application has low inter-particle morphological differences and high concentration. Batteries made using this negative electrode material have high batch yield and batch stability.

[0187] While numerous embodiments of this application have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will arise for those skilled in the art without departing from the spirit and intent of this application. It should be understood that various alternatives to the embodiments of this application described herein may be employed in the practice of this application. The appended claims are intended to define the scope of protection of this application and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A negative electrode material, said negative electrode material comprising a silicon-based material and a graphite-based material, characterized in that, The negative electrode material was subjected to Raman surface scanning testing, and 200 sets of spectra were randomly selected. Of the 200 sets of atlases, 500cm -1 -520cm -1 Let n be the number of spectra with peaks at each point. 500cm -1 -520cm -1 In the spectrum with a peak: 1345cm -1 -1355cm -1 The peak intensities at I are respectively A1 I A2 , ..., I An 1570cm -1 -1610cm -1 The peak intensities at I′ are respectively A1 , I′ A2 , ..., I′ An ; The negative electrode material satisfies the following relationship: in, And A≤0.

8.

2. The negative electrode material according to claim 1, characterized in that, The negative electrode material satisfies: 0.01≤A≤0.

8.

3. The negative electrode material according to claim 2, characterized in that, A satisfies one of the following conditions: a. The value of A is 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or within the range of any two of the above values; b. 0.01 ≤ A ≤ 0.5; c. 0.1 ≤ A ≤ 0.6; d.0.01≤A≤0.3; e.0.2≤A≤0.5; f.0.4≤A≤0.7; g.0.6≤A≤0.

8.

4. The negative electrode material according to claim 2, characterized in that, The negative electrode material satisfies the following relationship: B = (|I A1 / I' A1 - K| + |I A2 / I' A2 - K| + … + |I An / I' An - K|) / n, and 0 < B ≤ 0.

3.

5. The negative electrode material according to claim 4, characterized in that, B satisfies one of the following conditions: a. The value of B is 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, or within the range of any two of the above values; b. 0.01 ≤ B ≤ 0.2; c. 0.01 ≤ B ≤ 0.1; d.0.05≤B≤0.25; e.0.15≤B≤0.

3.

6. The negative electrode material according to any one of claims 1 to 5, characterized in that, The specific surface area of ​​the negative electrode material is <3.0 m². 2 / g.

7. The negative electrode material according to any one of claims 1 to 5, characterized in that, The moisture content of the negative electrode material is <0.5% by mass.

8. The negative electrode material according to any one of claims 1 to 5, characterized in that, The volume distribution of the negative electrode material particle size, D10, is greater than 1.0 μm.

9. The negative electrode material according to any one of claims 1 to 5, characterized in that, Based on the mass of the negative electrode material of 100wt%, the carbon content is 5wt% to 95wt%, and the silicon content is 5wt% to 95%.

10. The negative electrode material according to any one of claims 1 to 5, characterized in that, The negative electrode material includes at least one of the following characteristics: a. The gas production rate of the battery made of the negative electrode material during the aging process is <0.01mL / Ah; b. The battery made of the aforementioned negative electrode material, after being stored at 60°C for 15 days, produces <0.1 mL / Ah of gas.

11. The negative electrode material according to any one of claims 1 to 5, characterized in that, Of the 200 randomly selected sets of atlases, 500cm -1 -520cm -1 The ratio of the number of spectra with peaks to the number of spectra without peaks is 0.05-40.

12. The negative electrode material according to any one of claims 1 to 5, characterized in that, The silicon-based material includes at least one of amorphous silicon, crystalline silicon, silicon oxide, and silicate.

13. The negative electrode material according to any one of claims 1 to 5, characterized in that, The graphite materials include at least one of natural graphite, artificial graphite, expanded graphite, and graphite oxide.

14. The negative electrode material according to any one of claims 1 to 5, characterized in that, The negative electrode material includes carbon materials, and the carbon materials include at least one of amorphous carbon and graphitized carbon.

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

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