Fast-charging type silicon monoxide negative electrode material and preparation method and application thereof

Abstract

The invention relates to a fast-charge type silicon monoxide negative electrode material and a preparation method and application thereof, and the preparation method of the fast-charge type silicon monoxide negative electrode material comprises the following steps: mixing a lithium lithiation reagent and a silicon monoxide material for preliminary chemical lithiation, and then preparing the fast-charge type silicon monoxide negative electrode material through electrochemical lithiation, the non-bridging oxygen content ([non-bridging oxygen] / Si) is greater than or equal to 3.26. The fast-charging type silicon monoxide negative electrode material provided by the invention can be used for a fast-charging type lithium ion battery, and an interface of lithium oxide and lithium silicate is pre-formed in a chemical lithiation process, so that side reaction between silicon monoxide and an electrolyte is relieved; the high non-bridging oxygen silicate generated in the electrochemical lithiation process is beneficial to forming a rapid lithium ion channel in the silicon monoxide material, so that the diffusion coefficient of lithium ions in the material is improved, and rapid lithiation and delithiation of the silicon monoxide are realized; the prepared silicon monoxide negative electrode has high energy density and also has excellent fast charging capability under high current density.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery fast charging technology, specifically relating to a fast-charging silicon suboxide anode material, its preparation method, and its application. Background Technology

[0002] With the rapid development of the electric vehicle market, the demand for high-energy-density and high-power-density energy storage devices is increasing daily. Fast charging technology is key to solving range anxiety in electric vehicles. Currently, commercially available lithium-ion batteries mainly use graphite as the anode material, which has a relatively low theoretical specific capacity (372 mAh g⁻¹). -1 High specific capacity and low lithiation potential (<0.2 V vs Li) + Lithium dendrites (Li) have low tolerance for overpotential at high current densities, which can easily lead to the deposition of lithium metal on their surface. On the one hand, the deposited lithium metal will react with the electrolyte, causing the battery capacity to decay rapidly and reducing cycle life. On the other hand, the deposited lithium dendrites may puncture the separator, causing safety hazards such as short circuits. Obviously, this cannot meet the requirements of high energy density materials and high power density.

[0003] silicon suboxide (SiO) x The negative electrode has a high theoretical specific capacity (~2500 mAh g). -1 Li 3.75 Si) and a moderate electrochemical lithium intercalation potential (<0.5 V vs Li) + / Li), meeting people's demand for high energy density lithium-ion batteries, but silicon suboxide anodes themselves have poor ionic conductivity (~10). -8 S cm -1 ) and electronic conductivity (~10 -3 S cm -1 At high current densities, lithium oxide exhibits a large overpotential, reducing capacity utilization at high rates. It also leads to lithium metal deposition on the negative electrode surface, resulting in reduced cycle life and potentially safety hazards, thus failing to meet the high power density requirements of automotive power batteries. The question remains: how to improve the SiO₂ content... x The fast charging capability of the base anode under high current density is an urgent problem to be solved.

[0004] To address the aforementioned issues, researchers have improved the poor ionic and electronic conductivity of silicon suboxide (SiO2) through heteroelement doping and carbon coating. Carbon coating of SiO2 particles via vapor deposition significantly improves electronic conductivity. Heteroelement doping can improve the diffusion kinetics of lithium ions in SiO2. Recently, Professor Guo Yuguo's team at the Institute of Chemistry discovered that introducing Sn doping into the SiO2 anode accelerates lithium ion transport within the particles because Sn has superior ionic and electronic conductivity compared to Si and can form a three-dimensional conductive-ionic network during charge and discharge. However, heteroelement doping, due to its electrochemically inert state or its relatively large atomic mass, can reduce the energy density of the SiO2 anode and may also affect grain size, increasing production and processing costs.

[0005] During the first charge-discharge cycle, the Si-O matrix of the silicon suboxide anode is irreversibly lithilated to form lithium oxide (Li₂O) and lithium silicate (Li₂O) during chemical or electrochemical lithiation. x SiO y This results in a lower first-cycle coulombic efficiency (ICE). Therefore, in practical applications, the silicon suboxide anode is usually pre-lithiated to compensate for the loss of active lithium during the first cycle. Lithium silicates not only act as a buffer layer during battery charging and discharging to alleviate the significant volume expansion of Si during the formation of a Li-Si alloy with Li, but also possess a certain degree of ion conduction capability. Due to the high ionic conductivity of lithium silicates (10... -7 S cm -1 ) higher than Si (10 -8 S cm -1 Therefore, it is beneficial for lithium-ion transport in the early stage of lithium intercalation, while the subsequently formed Li-Si alloy has high ionic conductivity (10). -4 -10 -6 S cm -1 Silicates, ironically, become the rate-limiting step in the lithium intercalation process; therefore, the composition and structure of silicates significantly influence the rate of lithiation in SiO₂. x The lithium intercalation kinetics and fast charging capability are crucial. Lithium silicates are composed of a silicon-oxygen framework formed by interconnected silicon-oxygen tetrahedra. Oxygen atoms that participate in connecting adjacent silicon-oxygen tetrahedra are called bridging oxygens (BO), while oxygen atoms that only connect to one silicate tetrahedron and one metal cation and do not participate in connecting the silicon-oxygen tetrahedral network are called non-bridging oxygens (NBO). According to the research of Guo Yuguo's research group, NBO is more conducive to lithium-ion transport, while BO increases the lithium-ion diffusion activation energy. Therefore, how to achieve lithium intercalation kinetics and fast charging capability in SiO2 is crucial. x Constructing a silicon suboxide anode with high non-bridging oxygen content during the pre-lithiation process is of great significance for the practical application of high-energy-density silicon suboxide-based fast-charging lithium-ion batteries. Summary of the Invention

[0006] The purpose of this invention is to improve the diffusion kinetics of lithium ions in silicon suboxide anode materials by precisely controlling the lithium silicate phase and structure. To this end, this invention provides a fast-charging silicon suboxide anode material, its preparation method, and its applications.

[0007] The main objective of this invention is to provide a fast-charging silicon suboxide anode material, its preparation method, and its applications. The fast-charging silicon suboxide material is prepared by first reacting silicon suboxide with a lithium-organic compound to obtain a preliminary chemically lithiated silicon suboxide material, followed by electrochemical lithiation to obtain a silicon suboxide anode with high non-bridging oxygen content. Chemical lithiation can generate a stable interface containing lithium oxide and lithium silicate on the silicon suboxide surface, reducing side reactions between silicon suboxide particles and the electrolyte during electrochemical cycling. Subsequent electrochemical lithiation to generate silicates with high non-bridging oxygen content accelerates lithium-ion transport within the particles, resulting in excellent fast-charging performance.

[0008] A method for preparing a fast-charging silicon suboxide anode material includes the following steps:

[0009] (1) Carbon-coated silicon suboxide material was dispersed into a solution containing lithium-organic compounds under an inert atmosphere and low water environment. The mixture was stirred, centrifuged, washed, vacuum dried, and heated to remove residual organic impurities to obtain chemically lithiumized silicon suboxide powder Li. y SiO x ;

[0010] (2) Chemically lithium-ionized silicon suboxide powder Li y SiO x It is prepared into a negative electrode sheet and assembled into a battery;

[0011] (3) The above battery is electrochemically activated to obtain a silicon suboxide anode material with chemical and electrochemical coupling lithiation. The silicon suboxide anode material is tested by Raman spectroscopy and its non-bridging oxygen content ([non-bridging oxygen] / Si) is ≥3.26.

[0012] Preferably, the unbridged oxygen content ([unbridged oxygen] / Si) of the obtained silicon suboxide anode material is ≥3.4.

[0013] The non-bridging oxygen content is calculated using the following formula: [NBO] / Si = S i For Q i Peak area; Raman wavenumber range 400-1400 cm⁻¹ -1 ; Q on the Raman spectrum i (i represents the number of bridging oxygen atoms near Si) The peak wavenumber range is: Q0 peak 780-820 cm⁻¹-1 Q1 peak 880-930 cm -1 Q2 peak 970-1030 cm -1 , Q3 peak 1180-1130 cm -1 Q4 peak 1180-1230 cm -1 .

[0014] The inventors discovered that the silicon suboxide anode material obtained by first performing chemical physicochemical treatment and then electrochemical activation under certain conditions can first generate a stable interface containing lithium oxide and lithium silicate on the surface of silicon suboxide through chemical lithiation, reducing the side reactions between silicon suboxide particles and electrolyte during electrochemical cycling. Then, electrochemical lithiation is performed to generate silicates with high non-bridging oxygen content.

[0015] Further, in step (1), the silicon suboxide is SiO x The silicon material has a particle size of 0.9 ≤ x ≤ 1.3 and contains crystalline Si with a grain size < 5 nm. The inert atmosphere is nitrogen and / or argon. Carbon coating is achieved by in-situ coating of a carbon source gas onto the surface of the silicon suboxide material using chemical vapor deposition (CVD). Specifically, the carbon source gas is introduced and carbon coating is performed at 600-900 °C. The carbon source gas is selected from at least one of C1-4 alkanes, C2-4 alkenes, and C2-4 alkynes, such as methane, ethane, ethylene, and acetylene. Preferably, the carbon coating layer thickness is 2-10 nm.

[0016] Further, in step (1), the inert atmosphere is nitrogen and / or argon; the low-water environment is a moisture content ≤10ppm; the organic compound is at least one or a combination of benzene, biphenyl, naphthalene, and dimethylbenzene (correspondingly, the lithium-organic compounds are lithium-benzene, lithium-biphenyl, lithium-naphthalene, and lithium-dimethylbenzene compounds, respectively); the solvent is at least one or a combination of tetrahydrofuran (THF), 2-methyltetrahydrofuran, and dimethyl ethylene glycol (DME).

[0017] Further, in step (1), the concentration of lithium-organic compound in the lithium-organic compound solution is 0.1-0.5 mol / L, and the ratio of carbon-coated silicon suboxide material to lithium-organic compound is 1 kg: 7.5-15 mol; preferably 1 kg: 7.5-10 mol. The amount of lithium-organic compound used should not be too high, otherwise it will lead to over-lithiation of silicon suboxide and the adhesion of metallic lithium on the surface.

[0018] Further, in step (1), the stirring speed of the stirring reaction is 400-800 rpm and the reaction time is 8-12 h; the heating to remove organic residual impurities is carried out under an inert atmosphere, the heating temperature is 600-800℃, the holding time is 4-6 h, and the inert atmosphere is nitrogen and / or argon.

[0019] Furthermore, in step (2), the negative electrode is prepared by chemically lithium-ionizing silicon suboxide powder Li. y SiO x The conductive agent and adhesive are formulated into a slurry, coated onto the current collector, and dried to obtain the final product. Preferably, the conductive agent is selected from at least one of acetylene black, graphene, Super P, and KB; the adhesive is selected from at least one of polyacrylic acid (PAA) and carboxymethyl cellulose (CMC); and the current collector includes copper foil or aluminum foil. More preferably, the chemically lithium-ionized silicon suboxide powder Li... y SiO x The mass ratio of conductive agent to binder is 6-9.5:0.5-2:0.5-2, for example, 8-9:0.5-1:0.5-1; the battery also includes a separator and an electrolyte, or a solid electrolyte, wherein the solute of the electrolyte is a 0.5-2M lithium salt, preferably a 0.8-1.5M lithium salt, for example, a 1-1.2M lithium salt, wherein the lithium salt includes at least one of lithium bis(fluorosulfonyl)imide (LiFSI), lithium hexafluorophosphate (LiPF6), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and the solvent of the electrolyte is selected from at least one of ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC).

[0020] Furthermore, in step (3), the charging cutoff voltage range of the electrochemical activation process is 1.5-1.7V, the discharging cutoff voltage is 0.005-0.01V, and the activation current is 0.01-0.05C.

[0021] The present invention also provides a fast-charging silicon suboxide anode material prepared by the above preparation method.

[0022] A third objective of this invention is to provide the application of the fast-charging silicon suboxide anode material in lithium-ion fast-charging batteries.

[0023] A fourth objective of this invention is to provide a lithium-ion battery whose negative electrode comprises the aforementioned fast-charging silicon suboxide negative electrode material. Further, the negative electrode is a fast-charging silicon suboxide negative electrode material, and the conductive agent and binder are formulated as a slurry and coated onto the current collector.

[0024] Compared with the prior art, the advantages of the silicon-oxygen material with high non-bridging oxygen content provided by the present invention are as follows:

[0025] This invention precisely controls the bulk phase of high-capacity silicon suboxide materials. First, chemical lithiation generates a stable interface containing lithium oxide and lithium silicate on the silicon suboxide surface, reducing side reactions between silicon suboxide particles and the electrolyte during electrochemical cycling. Then, electrochemical lithiation generates silicates with high non-bridging oxygen content. Compared to bridging oxygen sites, lithium ions diffuse through non-bridging oxygen sites with a lower diffusion barrier, thus accelerating lithium ion diffusion within the silicon suboxide particles and improving the slow kinetics of silicon suboxide. This solves the problem of capacity reduction and grain size growth caused by the introduction of non-electrochemically active components through doping in the prepared anode, while also possessing excellent fast-charging capabilities. Lithium-ion batteries assembled from chemically and electrochemically coupled lithiated silicon suboxide anodes exhibit excellent fast-charging performance. Furthermore, the synthesis method of this invention is simple, the material cost is low, which is conducive to industrial production, and a new pre-lithiation scheme is proposed. Therefore, this chemically and electrochemically coupled lithiated silicon suboxide anode material has very broad practical application prospects. Attached Figure Description

[0026] Figure 1 This is a SEM image of the chemically lithiated silicon suboxide used in Example 1 of the present invention; Figure 2 This is a Raman diagram of Embodiment 1 of the present invention; Figure 3 The Raman spectrum of the silicon suboxide anode material prepared in Comparative Example 1 is shown. Figure 4 The Raman spectrum of the silicon suboxide anode material prepared in Comparative Example 2 is shown. Figure 5 The diffusion coefficients of Example 1, Comparative Example 1, and Comparative Example 2 are given. Figure 6 The first charge-discharge curves of the silicon suboxide anodes of Example 1, Comparative Example 1, and Comparative Example 2 at a rate of 0.05 C are shown. Figure 7 The capacitance-voltage differential curves for the first and second turns of Example 1 and Comparative Example 1 are shown. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0028] In the embodiments of this invention, if the experimental operating conditions are not explicitly marked, the experimental procedures of the corresponding technical field standards shall be referred to or the operating parameters recommended by the equipment supplier shall be adopted; the chemical reagents and experimental materials involved, unless otherwise specified, shall be purchased through conventional commercial channels in accordance with industry general standards.

[0029] Carbon-coated silicon suboxide material SiO x(x≈1.2) is derived from Anhui Yijin New Energy Technology Co., Ltd., with a carbon coating thickness of approximately 5nm.

[0030] Example 1

[0031] (1) 1 kg of carbon-coated silicon suboxide powder SiO x The mixture was mixed with 15 L of 0.5 M lithium-naphthalene DME solution, stirred at 800 rpm / min for 12 h, and then vacuum dried at 100 °C for 24 h. Afterwards, it was heated in a tube furnace at 700 °C for 5 h to remove organic compound impurities, yielding chemically lithiated silicon suboxide powder (Li). y SiO x .

[0032] (2) Li y SiO x The conductive carbon Super P and binder PAA were uniformly mixed at a mass ratio of 8:1:1, coated onto the surface of copper foil, and vacuum dried at 80 °C for 24 h to prepare a negative electrode sheet. Then, the negative electrode shell, negative electrode, separator, lithium metal foil, and positive electrode shell were assembled into a battery, and 1M LiPF6 electrolyte (EC:DEC:DMC volume ratio of 1:1:1) was added dropwise.

[0033] (3) Electrochemical lithiation: Discharge the battery to 0.005 V using a current density of 0.05 C, let it stand for 5 min, then charge the battery to 1.5 V using a current density of 0.05 C, and let it stand for 5 min.

[0034] (4) Disassemble the battery and collect the negative electrode material for Raman testing, and find the values ​​of 800, 920, 980, 1100, and 1200 cm⁻¹ in the Raman curve. -1 Find the corresponding signal peaks of Q0, Q1, Q2, Q3, and Q4 in the vicinity, and calculate the corresponding peak area S. i According to the formula: [NBO] / Si = The calculated non-bridging oxygen content is 3.50.

[0035] Figure 1 The image shows a scanning electron microscope (SEM) image of the silicon suboxide anode material prepared in Example 1, with a particle size of approximately 5 μm. Figure 2 This is the Raman spectrum of the silicon suboxide anode material prepared in Example 1.

[0036] Example 2

[0037] This embodiment differs from Embodiment 1 in that, during chemical lithiation, 1 kg of carbon-coated silicon suboxide powder (SiO) is used. x Mix with 20 L of 0.5 M lithium-naphthalene DME solution, and follow the same steps as in Example 1.

[0038] Example 3

[0039] This embodiment differs from Embodiment 1 in that, during chemical lithiation, 1 kg of carbon-coated silicon suboxide powder (SiO) is used. x The other steps are the same as in Example 1, involving mixing with 25 L of 0.5 M lithium-naphthalene DME solution.

[0040] Example 4

[0041] This embodiment differs from Embodiment 1 in that, during chemical lithiation, 1 kg of carbon-coated silicon suboxide powder (SiO) is used. x The other steps are the same as in Example 1, involving mixing with 30 L of 0.5 M lithium-naphthalene DME solution.

[0042] Comparative Example 1

[0043] Comparative Example 1 differs from Example 1 in that, during chemical lithiation, 1 kg of carbon-coated silicon suboxide powder (SiO) was used. x It was mixed with 35 L of a 0.5 M lithium-naphthalene reducing solution, and the other steps were the same as in Example 1.

[0044] Figure 3 This is the Raman spectrum of the silicon suboxide anode material prepared in Comparative Example 1.

[0045] Comparative Example 2

[0046] The difference between Comparative Example 2 and Example 1 is that the carbon-coated silicon suboxide material does not undergo the chemical lithiation step in step 1, while the steps after the silicon suboxide material is assembled into a battery are the same. Figure 4 This is the Raman spectrum of the silicon suboxide anode material prepared in Comparative Example 2.

[0047] Application examples

[0048] Raman spectroscopy was performed on the silicon suboxide anode to identify the 800, 920, 980, 1100, and 1200 cm⁻¹ values ​​in the Raman curve. -1 The corresponding signal peaks of Q0, Q1, Q2, Q3 and Q4 in the vicinity. Figure 2 The Raman spectrum for Example 1 is shown. The non-bridging oxygen content in silicon suboxide was calculated using the formula and expressed as [non-bridging oxygen] / Si. The results show that the lower the degree of chemical lithiation, the higher the non-bridging oxygen content in the silicon suboxide silicate phase obtained by electrochemical lithiation.

[0049] Electrochemical analysis was performed on a half-cell with a silicon suboxide anode containing high non-bridging oxygen content at 25 °C, with a charge / discharge voltage window of 0.005–1.5 V (vs. Li). + / Li), Figure 5To determine the diffusion coefficient of lithium ions in Example 1, Comparative Example 1 and Comparative Example 2 using the intermittent titration technique (GITT), the results showed that the higher the non-bridging oxygen content in the silicate suboxide phase, the higher the lithium ion diffusion coefficient of the material. Figure 6 The figures show the first charge-discharge curves of the silicon suboxide anodes of Examples 1, 1 Comparative Example, and 2 at a rate of 0.05 C. Due to the different degrees of lithiation, the reversible specific capacity of Example 1 reaches 1538.8 mAh g. -1 Comparative Example 1: Reversible specific capacity 1420.2 mAh g -1 The reversible specific capacity of Comparative Example 2, which did not undergo chemical lithiation, was 1586.1 mAh g⁻¹. -1 . Figure 7 The figures show the capacity-voltage differential curves for the first and second cycles of Example 1 and Comparative Example 1. Example 1 shows a signal peak at 0.3 V in the first cycle, which disappears in the second cycle. This indicates that the silicate phase in the silicon suboxide of Example 1 underwent irreversible electrochemical lithiation in the first cycle. In contrast, Comparative Example 1 showed no peak at 0.3 V in either the first or second cycle, indicating that the silicate phase in the silicon suboxide of Comparative Example 1 did not undergo irreversible electrochemical lithiation. This is because in Comparative Example 1, during the chemical lithiation process, the SiO2 matrix in the silicon suboxide was completely lithiated into silicate by the naphthalene lithium reagent, and no additional reaction occurred during electrochemical lithiation.

[0050] The electrochemical performance of the silicon suboxide anode materials in the examples and comparative examples was tested according to the above method, and the results are shown in Table 1 below:

[0051] Table 1 Electrochemical performance test of silicon suboxide anode material

[0052]

[0053] For silicates, higher lithium content results in higher non-bridging oxygen content. Due to differences in lithiation potential, electrochemical lithiation reduction potential using metallic lithium as the lithium source is lower, leading to deeper lithiation and the acquisition of silicon suboxide anode materials with high non-bridging oxygen content. Silicon suboxide anode materials obtained through chemical and electrochemical lithiation exhibit electrochemical inertness during subsequent electrochemical cycles, preventing further lithiation reactions. Table 1 shows that, following the order of Examples 1-4, increasing the proportion of lithiation reagent leads to a greater degree of chemical lithiation. Therefore, the proportion of silicate Li4SiO4 with high non-bridging oxygen content decreases through electrochemical lithiation, resulting in a lower overall non-bridging oxygen content and a slightly lower rate performance compared to Example 1. However, when [non-bridging oxygen] / Si ≥ 3.26, the capacity retention rate at 4C is higher than 70%. The preferred Examples 1 and 2 maintain a capacity retention rate higher than 80% at 4C, demonstrating considerable fast-charging capability. Figure 7The dQ / dV curve results show that, due to the use of a higher concentration of naphthalene-lithium reagent in Comparative Example 1, the SiO2 matrix in silicon suboxide can be completely converted into silicates with low non-bridging oxygen content. Furthermore, these silicates are electrochemically inert and do not form high-non-bridging oxygen content Li4SiO4 silicates during electrochemical lithiation, unlike the silicon suboxide in Examples 1-4. Therefore, the low non-bridging oxygen content results in poor rate performance. Although the silicon suboxide in Comparative Example 2 only underwent electrochemical lithiation, the generated silicate was mainly Li4SiO4 with the highest non-bridging oxygen content. However, because it did not form a stable interface containing lithium oxide and lithium silicate during chemical lithiation, it was prone to side reactions with the electrolyte during electrochemical cycling, leading to rapid capacity decay and failing to achieve good fast-charging performance. Therefore, the silicon suboxide anode of this invention, which undergoes chemical and electrochemically coupled lithiation, combines high-non-bridging oxygen content silicates with a stable lithium oxide and lithium silicate interface. This improves lithium-ion diffusion kinetics while exhibiting higher interface stability, resulting in better fast-charging capability.

[0054] In summary, the method of the present invention is simple and efficient. Based on commercial silicon suboxide materials, chemical lithiation can be performed first using organometallic lithium reagents, followed by electrochemical lithiation using lithium sources such as lithium-replenishing membranes and lithium foils. This ensures that the anode has high rate performance, excellent cycle stability, and high initial coulombic efficiency.

Claims

1. A method for preparing a fast-charging silicon monoxide negative electrode material, characterized by, The method comprises the following steps: (1) dispersing carbon-coated silicon monoxide material into a solution containing lithium-organic compound under inert atmosphere and low water environment, stirring reaction, centrifugal washing, vacuum drying, heating to remove organic residual impurities to obtain chemically lithiated silicon monoxide powder Li y SiO x ; (2) The chemical lithiation of the fumed silica powder Li y SiO x The negative electrode sheet is prepared and assembled into a battery. (3) electrochemically activating the above battery to obtain a silicon monoxide negative electrode material with chemical and electrochemical coupling lithiation, wherein the silicon monoxide negative electrode material has a non-bridging oxygen content ([non-bridging oxygen] / Si) ≥3.26 in Raman spectrum test.

2. The production method according to claim 1, characterized by, The obtained silicon monoxide negative electrode material has a non-bridging oxygen content ([non-bridging oxygen] / Si) ≥3.

4.

3. The preparation method according to claim 1, characterized in that, In step (1), the silicon monoxide is SiO x , 0.9≤x≤1.3, having a crystalline state with a grain size <5 nm; the inert atmosphere is nitrogen and or argon; the carbon coating layer is 2-10 nm thick.

4. The method of claim 1, wherein, In step (1), the organic compound is at least one or a combination of benzene, biphenyl, naphthalene, and dimethylbenzene; and the solvent is at least one or a combination of tetrahydrofuran (THF), 2-methyltetrahydrofuran, and dimethoxyethane (DME).

5. The preparation method according to claim 1, characterized in that, In step (1), the concentration of lithium-organic compound in the lithium-organic compound solution is 0.1-0.5 mol / L, and the ratio of the carbon-coated silicon monoxide material to the lithium-organic compound is 1 kg: 7.5-15 mol, preferably 1 kg: 7.5-10 mol.

6. The preparation method according to claim 1, characterized in that, In step (2), the preparation of the negative electrode sheet is to mix the chemically lithiated silicon monoxide powder Li y SiO x , a conductive agent and a binder to prepare a slurry, coat the slurry on a current collector, and dry to obtain the negative electrode sheet; preferably, the conductive agent is selected from at least one of acetylene black, graphene, Super P, KB, the binder is selected from at least one of polyacrylic acid (PAA) and carboxymethyl cellulose (CMC), and the current collector includes a copper foil or an aluminum foil; more preferably, the chemically lithiated silicon monoxide powder Li y SiO x , the conductive agent and the binder have a mass ratio of 6-9.5:0.5-2:0.5-2, and preferably 8-9: 0.5-1：0.5-1。 7. The preparation method according to claim 1, characterized in that, In step (3), the charging cutoff voltage interval of the electrochemical activation process is 1.5-1.7 V, the discharging cutoff voltage is 0.005-0.01 V, and the activation current size is 0.01-0.05 C.

8. A fast-charging silicon monoxide negative electrode material prepared by the preparation method of any one of claims 1-7.

9. Use of the fast-charging silicon monoxide negative electrode material prepared by the preparation method of any one of claims 1-7 in preparing a negative electrode for a lithium ion fast-charging battery.

10. A lithium-ion battery, characterized by, The negative electrode comprises the fast-charging silicon monoxide negative electrode material prepared by the preparation method of any one of claims 1-7; further, the negative electrode is the fast-charging silicon monoxide negative electrode material prepared by the preparation method of any one of claims 1-7, a conductive agent, and a binder, which are formulated into a slurry and coated on a current collector.

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