Siloxene materials with controllable surface oxygen components, and preparation method and application thereof

Abstract

The application provides a silicon-oxygen material with controllable surface oxygen components, a preparation method thereof and application thereof in lithium ion batteries, and belongs to the technical field of materials. The silicon-oxygen material is obtained by molten salt etching of a silicon alloy phase material. The preparation method is as follows: a molten salt system with a specific composition is kept at a suitable temperature for heat preservation etching together with the silicon alloy phase material, and after washing, separation and drying, a two-dimensional silicon-oxygen material with an accurately controllable surface oxygen component content can be obtained. By adjusting the composition (cations and their ratio) of the molten salt system, the surface chemical activity of the silicon-based material in the etching process can be effectively adjusted, and then the process of introducing oxygen to the surface and the accurate control of the final oxygen component content can be realized. Through this method, the structure-activity relationship between the surface oxygen component of the silicon-oxygen material and the electrochemical performance thereof can be systematically explored and established. The method has the advantages of strong universality, simple process, low temperature and low energy consumption, the prepared material has a sheet structure, and is suitable for negative electrode materials of high-performance lithium ion batteries.

Description

Technical Field

[0001] This invention belongs to the field of secondary battery materials technology, specifically relating to siloxane materials with controllable surface oxygen composition, their preparation methods, and their applications in lithium-ion batteries. Background Technology

[0002] Lithium-ion batteries are widely used in portable electronic devices, electric vehicles, and hybrid vehicles. As a key component of the battery, the anode material significantly impacts battery performance. Currently, commercially available lithium-ion batteries commonly use graphite anodes, but their theoretical specific capacity is only 372 mAh / g, which is insufficient to meet the demands for high energy density, thus limiting the further development of high-energy lithium-ion batteries. Silicon-based anodes, due to their ultra-high theoretical capacity (4200 mAh / g), abundant reserves, and environmental friendliness, are considered one of the most promising next-generation lithium-ion battery anode materials. However, traditional silicon materials undergo dramatic volume expansion (~300%) during lithium insertion / extraction, leading to electrode pulverization, intensified interfacial side reactions, and a sharp decline in cycle life, severely restricting their commercialization.

[0003] Two-dimensional layered silicon materials exhibit relatively high reversible specific capacity, small volume change, and good cycle performance, making them highly promising for development. Current mainstream synthesis methods, such as topological deintercalation, high-temperature sintering, or electrochemical exfoliation, typically suffer from complex processes, demanding conditions, and long reaction cycles. The substantial investment required for specialized equipment in these methods leads to high production costs, severely hindering the large-scale preparation and commercial application prospects of these materials. Therefore, there is an urgent need to provide a simple, low-temperature, and low-energy-consumption method for preparing two-dimensional siloxane materials. Summary of the Invention

[0004] The present invention aims to solve the above-mentioned problems of the prior art, and its purpose is to provide siloxane materials with controllable surface oxygen composition, their preparation methods and their applications in lithium-ion batteries.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, a siloxane material with controllable surface oxygen composition is provided, wherein the siloxane material particles are composed of stacked nanosheets.

[0006] Furthermore, the thickness of the siloxane material particles is 1~10μm.

[0007] Furthermore, the thickness of the nanosheet is 1~100nm.

[0008] Furthermore, the chemical formula of the siloxane material is SiO₂. x Where 0 ≤ x < 1.5; preferably the SiO x In this process, the molar ratio of Si to O is 70-85%.

[0009] Secondly, a method for preparing siloxane materials with controllable surface oxygen composition is provided, including: The layered silicon alloy raw material is mixed evenly with molten salt, and heated to above the melting point of the molten salt in a sealed container filled with inert gas. The mixture is then kept at this temperature for a period of time to obtain a siloxane-molten salt mixture. The siloxane-molten salt mixture was washed with dilute acid solution to obtain a yellow-brown / brown-black suspension; The yellow-brown / brown-black suspension was washed with water, subjected to solid-liquid separation, and dried to obtain layered siloxane material SiO. x , where 0 ≤ x < 1.5.

[0010] Thirdly, a negative electrode is provided, wherein the active material of the negative electrode includes the siloxane material described in the first aspect or the siloxane material prepared by the preparation method described in the second aspect.

[0011] Fourthly, a lithium-ion battery is provided, including the negative electrode described in the third aspect.

[0012] Compared with the prior art, one or more of the above technical solutions can achieve at least one of the following beneficial effects: (1) The two-dimensional siloxane material prepared in this invention has a controllable surface oxygen composition (Si / O ratio). By regulating the surface oxygen composition, volume expansion can be effectively suppressed, and its electrochemical performance can be further optimized. There is a clear structure-property relationship between surface oxygen composition and electrochemical performance: when the surface oxygen composition is high, the structural stability is enhanced, exhibiting excellent cycling stability, but the reversible capacity is relatively low; while when the surface oxygen composition is too low, although the material can provide a higher theoretical capacity, the surface Si activity is too high, the structure degrades quickly during cycling, and the stability is insufficient.

[0013] (2) This invention achieves controllable adjustment of the surface oxygen state by regulating the molten salt system. Specifically, for example, M1-type cationic salts and M2-type cationic salts can be selected as molten salts, such as CH3COO - Using M1-type cations as anions, the M1-type cations, as Lewis acids, possess oxidizing capabilities and play a dominant role in the etching and stripping of CaSi2. By adjusting the ratio of M1-type cations to M2-type cations, molten salt matrices with different oxidizing strengths can be formed, thereby achieving different degrees of etching during subsequent stripping processes. Ultimately, two-dimensional siloxane materials with controllable surface oxygen composition are obtained. When the molar proportion of M1-type cations in the total cations of the molten salt is within a certain range, the oxidizing ability is moderate, and siloxane materials with suitable Si / O ratios can be obtained, thus yielding siloxane materials with both excellent specific capacity and cycle stability.

[0014] (3) The preparation method of the present invention is simple. By adjusting the type and ratio of cations in the molten salt matrix, the oxygen composition on the material surface can be effectively controlled. At the same time, the method has low energy consumption, the reaction temperature is below 400℃, the process is simple and efficient, easy to scale up production, and has good prospects for industrial application. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 These are the SEM test results of the two-dimensional siloxane material in Example 1 of this invention; Figure 2 These are the SEM test results of the two-dimensional siloxane material in Example 2 of this invention; Figure 3 These are the SEM test results of the two-dimensional siloxane material in Example 3 of this invention; Figure 4 These are the XRD patterns of the two-dimensional siloxane materials in Examples 1-3 of this invention; Figure 5 This is a TEM image of the two-dimensional siloxane material in Embodiment 3 of the present invention; Figure 6 This is a diagram showing the Si and O content ratios of the two-dimensional siloxane material XPS in Examples 1-3 of the present invention; Figure 7 These are cycle performance diagrams of the two-dimensional siloxane materials in Examples 1-3 of the present invention. Detailed Implementation

[0017] Some embodiments of the present invention provide siloxane materials with controllable surface oxygen composition, wherein the siloxane material particles are composed of a stack of numerous nanosheets.

[0018] This invention effectively regulates the surface chemical activity of silicon-based materials during etching by controlling the composition of the molten salt system (the types and ratios of cations), thereby achieving precise control over the process of introducing oxygen onto the surface and the final oxygen content. This method allows for a systematic investigation and establishment of the relationship between molten salt composition, oxygen composition on the siloxane surface, and electrochemical performance, providing experimental technical support for material structural design.

[0019] In some preferred embodiments, the thickness of the siloxane material particles is 1~10μm, such as 1μm, 2μm, 3μm, 4μm, μm, 6μm, 7μm, 8μm, 9μm, 10μm, etc.; the thickness of the nanosheets is 1~100nm, such as 1nm, 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, 100nm, etc.

[0020] In some preferred embodiments, the chemical formula of the siloxane material is SiO2. x Where 0 ≤ x < 1.5, the SiO2 is further preferred. x In this process, the molar ratio of Si to O is 70-85%, such as 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, etc., and more preferably 75-80%, such as a Si / O ratio of about 79.2%.

[0021] Some embodiments provide a method for preparing siloxane materials with controllable surface oxygen composition, including: After the layered silicon alloy raw material is mixed evenly with molten salt, it is placed in a sealed container filled with inert gas, such as N2 / Ar, and then placed in a heating device to be heated to above the melting point of the molten salt. The mixture is kept at this temperature for a period of time to obtain a siloxane-molten salt mixture. The siloxane-molten salt mixture was washed with dilute acid solution to obtain a yellow-brown / brown-black suspension; The yellow-brown / brown-black suspension was washed with water, subjected to solid-liquid separation, and dried to obtain layered siloxane material SiO. x , where 0 ≤ x < 1.5.

[0022] In some preferred embodiments, the layered silicon alloy raw material is a Zintl phase silicon compound; the Zintl phase silicon compound is ASi2, wherein A is a divalent metal such as Ca, Mg, Li, Sr, Ba, Eu, Yb, or Fe.

[0023] In some preferred embodiments, the melting point of the molten salt is below 400°C; the molten salt is composed of salts corresponding to a single cation or multiple cations; the molten salt is one or more of chlorides, nitrates, acetates, etc.; the cations of the molten salt include Li. + Na + K + Al 3+ Zn 2+ Cu 2+NH4 + Ca 2+ Mg 2+ Co 2+ and Sn 2+ One or more of them.

[0024] The molten salts, classified by cation, may include the following systems: Lithium salt systems: such as LiCl, LiNO3, CH3COOLi, etc.; Sodium salt systems: such as NaCl, NaNO3, NaNO2, CH3COONa, etc.; Potassium salt systems: such as KCl, KNO3, CH3COOK, etc.; Aluminum salt systems: such as AlCl3, Al(NO3)3, (CH3COO)3Al, etc.; Zinc salt systems: such as ZnCl2, Zn(NO3)2, (CH3COO)2Zn, etc.; Copper salt systems: such as CuCl2, CuCl, etc.; Ammonium salt systems: such as NH4NO3, NH4Cl, etc.; Calcium salt systems: such as CaCl2, Ca(NO3)2·4H2O, Ca(CH3COO)2·H2O, etc.; Magnesium salt systems: such as MgCl2, Mg(CH3COO)2·4H2O, etc.

[0025] The molten salts mentioned above can be used alone or can be mixed with multiple salts corresponding to the same cation or different cations to form a composite etching system, such as a mixed system of chloride and nitrate, or a mixed system of chlorides with different cations.

[0026] In some preferred embodiments, the cation of the molten salt is a mixture of M1-type cations and M2-type cations, wherein the M1-type cation is Zn. 2+ Al 3+ Cu 2+ Co 2+ and Sn 2+ One or more of the following; the M2 type cation is Li + Na + K + NH4 + Ca 2+ Mg 2+One or more of the following are present, and the molar amount of M1-type cations in the molten salt is 50-100% of the total molar amount of cations in the molten salt, more preferably 55-80%, such as 55%, 58%, 60%, 62%, 64%, 66%, 68%, 70%, 72%, 74%, 76%, 78%, 80%, etc. In this invention, by adjusting the ratio of oxidizing cations to other ions, a two-dimensional siloxane material with controllable surface oxygen composition is obtained, further regulating and optimizing the electrochemical performance.

[0027] In some preferred embodiments, the heat preservation temperature is 80~400℃, such as 80℃, 100℃, 120℃, 140℃, 160℃, 180℃, 200℃, etc.; the heat preservation time is 8~24h, such as 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h, etc.

[0028] It is worth noting that in the above preparation method, the amount of molten salt used is excessive. Generally speaking, the mass of M1 type cationic salt in the molten salt is 3 to 30 times the mass of the layered silicon alloy raw material, such as 3 times, 5 times, 8 times, 10 times, 15 times, 20 times, 25 times, 30 times, etc.

[0029] In some preferred embodiments, when the layered silicon alloy raw material is mixed evenly with molten salt, the mixture of the layered silicon alloy raw material and molten salt is further ground into powder.

[0030] In some preferred embodiments, the dilute acid solution is one of dilute hydrochloric acid, dilute sulfuric acid, dilute oxalic acid, dilute nitric acid, dilute perchloric acid, dilute hypochlorous acid, dilute phosphoric acid, dilute acetic acid, etc.; the pH value of the dilute acid solution is between 0 and pH < 7, for example, 0, 1, 2, 3, 4, 5, 6, 6.5, etc.

[0031] In some embodiments, the water washing uses deionized water or the like, and the washing is performed more than twice; the solid-liquid separation is centrifugal separation; the drying can be any one of vacuum drying, freeze drying, fluidized bed drying, microwave drying, infrared drying, adsorption drying, etc., and the drying time is >6 hours. The specific drying time can be selected according to conventional needs.

[0032] Some embodiments provide a negative electrode, the active material of which includes the aforementioned siloxane material.

[0033] Some implementations provide a lithium-ion battery, including the aforementioned negative electrode.

[0034] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0035] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0036] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0037] The silicon alloy phase raw material used in the following embodiments of the present invention has a particle size of 1~30μm.

[0038] When testing the electrochemical performance of the following embodiments, the target materials were first assembled into coin cells as follows: A siloxane material, sodium alginate, and Super P were mixed in a mass ratio of 7:2:1 with an appropriate amount of water to form an electrode slurry. The slurry was then coated onto a Cu foil using an automatic coating machine to a thickness of 100 μm, forming an electrode sheet. The electrode sheet was then dried in a vacuum drying oven at 70°C for 12 h, and cut into small circular pieces with a diameter of 12 mm to serve as electrode sheets. A 16 mm diameter lithium metal sheet was used as the counter electrode, a 19 mm diameter Celgard 2325 separator, and an organic solution of LiPF6 / EC+DEC (volume ratio 1:1) / FEC (mass fraction 10%) was used as the electrolyte. Battery assembly is completed in an argon-protected glove box (H2O≤ 0.1ppm, O2≤ 0.1ppm). The positive electrode shell, electrode, separator, electrolyte, lithium plate, gasket, spring, and negative electrode shell are placed in the order from bottom to top. The assembled battery is then sealed using a button battery sealing machine.

[0039] During the battery cycle performance test, the first three cycles were activated at a current density of 200 mA / g, and then the battery was charged and discharged 100 times at a current density of 1000 mA / g, with a voltage range of 0.01V to 1.5V.

[0040] Example 1 A siloxane material with controllable surface oxygen composition, its preparation method, and its application in a lithium-ion battery, comprising the following steps: Step 1: Preparation (1) Preparation of etching salt According to the etching salt system formula, weigh 10g of etching salt (CH3COO)2Zn raw material and grind the salt evenly. Step 2: Etching the alloy phase (2) Take 1g of layered silicon alloy phase CaSi2 as raw material, grind the powder etching salt and silicon alloy raw material evenly until there is no particle-like powder, and then put it into a sealed container filled with N2 / Ar. (3) Place the container containing the uniformly mixed powder in a heating oven / box furnace or other device, and heat it to a temperature higher than its mixing melting point for etching. This will etch the layered alloy phase and obtain a siloxane-etching salt mixture. The temperature was 198 ℃, and the holding time was 10 hours. Step 3: Post-processing (4) The siloxane-etching mixture was washed with diluted hydrochloric acid solution to remove excess etching salt, resulting in a yellow-brown / brown-black suspension in 0.1M HCl. (5) The yellow-brown / brown-black suspension was repeatedly washed with deionized water and centrifuged to separate the solid and liquid. The solid product was vacuum dried to obtain a two-dimensional layered siloxane material. Step 4: Battery Assembly and Testing (6) Test the oxygen content of the prepared siloxane anode material, assemble it into a button cell according to the aforementioned battery assembly process, and perform electrochemical performance testing. (7) The atomic ratio analysis of the prepared siloxane anode by XPS test showed that the oxygen content was about 42.3%, the Si content was about 57.7%, the Si / O atomic ratio was about 73.3%, the initial charge capacity was 954.9 mAh / g, and the retention rate after 100 cycles was 96.8%.

[0041] Example 2 A siloxane material with controllable surface oxygen composition, its preparation method, and its application in a lithium-ion battery, comprising the following steps: Step 1: Preparation (1) Preparation of etching salt According to the composition of the etching salt raw materials in the etching salt system, weigh the etching salt raw materials (CH3COO)2Zn and CH3COOLi, with a molar ratio of 0.6:0.4, of which (CH3COO)2Zn is 10 g, and grind the etching salt evenly. Step 2: Etching the alloy phase (2) Take 1g of layered silicon alloy phase CaSi2 as raw material, grind the powder etching salt and silicon alloy raw material evenly until there is no particle-like powder, and then put it into a sealed container filled with N2 / Ar. (3) Place the container containing the uniformly mixed powder in a heating oven / box furnace or other device, and heat it to a temperature higher than its mixing melting point for etching. This will etch the layered alloy phase and obtain a siloxane-etching salt mixture. The temperature was 198 ℃, and the holding time was 10 hours. Step 3: Post-processing (4) The siloxane-etching mixture was washed with diluted hydrochloric acid solution to remove excess etching salt, resulting in a yellow-brown / brown-black suspension in 0.1 M HCl. (5) The yellow-brown / brown-black suspension was repeatedly washed with deionized water and centrifuged to separate the solid and liquid. The solid product was vacuum dried to obtain a two-dimensional layered siloxane material. Step 4: Battery Assembly and Testing (6) Test the oxygen content of the prepared siloxane anode material, assemble it into a button cell according to the aforementioned battery assembly process, and perform electrochemical performance testing. (7) The atomic ratio analysis of the prepared siloxane anode by XPS test showed that the oxygen content was about 55.8%, the Si content was about 44.2%, the Si / O atomic ratio was about 79.2%, the initial charge capacity was 1379.6 mAh / g, and the retention rate after 100 cycles was 88.0%.

[0042] Example 3 A siloxane material with controllable surface oxygen composition, its preparation method, and its application in a lithium-ion battery, comprising the following steps: Step 1: Preparation (1) Preparation of etching salt According to the composition of the etching salt raw materials in the etching salt system, weigh the etching salt raw materials (CH3COO)2Zn, CH3COONa, and CH3COOLi in a molar ratio of 0.5:0.3:0.2, of which (CH3COO)2Zn is 10g. Grind the etching salt evenly. Step 2: Etching the alloy phase (2) Take 1g of layered silicon alloy phase CaSi2 as raw material, grind the powder etching salt and silicon alloy raw material evenly until there is no particle-like powder, and then put it into a sealed container filled with N2 / Ar. (3) Place the container containing the uniformly mixed powder in a heating oven / box furnace or other device, and heat it to a temperature higher than its mixing melting point for etching. This will etch the layered alloy phase and obtain a siloxane-etching salt mixture. The temperature was 198℃, and the holding time was 10 hours. Step 3: Post-processing (4) The siloxane-etching mixture was washed with diluted hydrochloric acid solution to remove excess etching salt, resulting in a yellow-brown / brown-black suspension in 0.1M HCl. (5) The yellow-brown / brown-black suspension was repeatedly washed with deionized water and centrifuged to separate the solid and liquid. The solid product was then vacuum dried to obtain a two-dimensional layered silicate material. Step 4: Battery Assembly and Testing (6) Test the oxygen content of the prepared siloxane anode material, assemble it into a button cell according to the aforementioned battery assembly process, and perform electrochemical performance testing. (7) The atomic ratio analysis of the prepared siloxane anode by XPS test showed that the oxygen content was about 55.5%, the silicon content was about 44.5%, the Si / O atomic ratio was about 80.2%, the initial charge capacity was 1666.8 mAh / g, and the retention rate after 100 cycles was 84.4%.

[0043] Figures 1-3 These are SEM images of the two-dimensional siloxane materials from Examples 1-3. All the silicon materials show a layered structure composed of stacked nanosheets, which is the structure left after the Ca is etched away by the etching salt. Correspondingly, if the raw materials are changed to LiSi2, FeSi2, MgSi2, etc., after etching salt treatment, Li, Fe, and Mg can also be removed in the post-processing to prepare two-dimensional nano-silicon materials.

[0044] Figure 4 The TEM image of the two-dimensional siloxane in Example 3 shows that the primary particles of siloxane are sheet-like, further proving that the morphology of its secondary particles is a stacked sheet-like structure.

[0045] Figure 5 The images shown are XRD patterns of two-dimensional siloxanes from Examples 1-3. All silicon materials correspond to PDF card 27-1402. Figure 6 Images showing the Si and O content ratios of XPS in two-dimensional siloxanes in Examples 1-3 demonstrate that the synthesized material is a siloxane material, and that different etching systems can controllably passivate the siloxane surface, exhibiting different Si and O contents.

[0046] Figure 7 These are cycling performance diagrams of the two-dimensional siloxane materials in Examples 1-3. Siloxanes synthesized by different etching systems and temperatures have different capacities and cycling performances.

[0047] Table 1 shows the specific relationship between the oxygen composition (Si / O ratio) on the surface of the siloxane materials in Examples 1-3 and their capacity and retention rate.

[0048] according to Figure 7 Based on the specific data in Table 1, the amount of highly oxidizing Zn in the molten salt matrix was adjusted. 2+ Two-dimensional siloxane materials with different Si / O ratios were prepared by varying the proportions, and their electrochemical performance was controlled. Zn in the molten salts of Examples 1 to 3... 2+As the proportion decreases, the oxidizing power of the matrix gradually weakens within the same reaction time. In Example 1, the highly oxidizing molten salt significantly oxidizes the CaSi2 material, resulting in a high oxygen content on the surface of the siloxane, with a Si / O ratio of only 70.3%, leading to a lower capacity of 954.9 mAh / g, but excellent cycling performance with a 96.8% retention rate after 100 cycles. In Example 3, the oxidizing power of the molten salt is weakened, resulting in a lower oxygen content on the surface of the subsequently prepared siloxane material, with a Si / O ratio of 80.3%, a higher capacity of 1666.8 mAh / g, and a 84.4% retention rate after 100 cycles. This demonstrates that a strong oxidizing power of the molten salt can lead to a two-dimensional siloxane material with a high oxygen content, further exhibiting slightly lower capacity but excellent cycling stability. In summary, by rationally controlling the proportion of highly oxidizing cations in the molten salt, the Si / O ratio can be appropriately controlled, thereby obtaining siloxane materials that combine both capacity and cycling stability.

[0049] Table 1 The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A siloxane material with controllable surface oxygen composition, characterized in that, The siloxane material particles are composed of stacked nanosheets.

2. The siloxane material with controllable surface oxygen composition as described in claim 1, characterized in that, The thickness of the siloxane material particles is 1~10μm; the thickness of the nanosheets is 1~100nm.

3. The siloxane material with controllable surface oxygen composition as described in claim 1, characterized in that, The chemical formula of the siloxane material is SiO₂. x Where 0 ≤ x < 1.5; preferably the SiO x In this process, the molar ratio of Si to O is 70-85%.

4. A method for preparing siloxane materials with controllable surface oxygen composition, characterized in that, include: Layered silicon alloy raw material is mixed evenly with molten salt and heated to above the melting point of molten salt in a sealed container filled with inert gas. The mixture is kept at this temperature for a period of time to obtain a siloxane-molten salt mixture. The siloxane-molten salt mixture is washed with dilute acid solution to obtain a yellow-brown / brownish-black suspension. The yellow-brown / brown-black suspension was washed, separated from its solid state, and dried to obtain layered siloxane material SiO. x , where 0 ≤ x < 1.

5.

5. The method for preparing a siloxane material with controllable surface oxygen composition as described in claim 4, characterized in that, The layered silicon alloy raw material is a Zintl phase silicon compound; The Zintl phase silicon compound is ASi2, where A is a divalent metal such as Ca, Mg, Li, Sr, Ba, Eu, Yb, or Fe; the particle size of the layered silicon alloy raw material is 1~30 μm. The molten salt has a melting point below 400°C; the molten salt is composed of salts corresponding to a single cation or multiple cations; the molten salt is one or more of chlorides, nitrates, acetates, etc.; the cations of the molten salt include Li. + Na + K + Al 3+ Zn 2+ Cu 2+ NH4 + Ca 2+ Mg 2+ Co 2+ and Sn 2+ One or more of the following; preferably, the cation of the molten salt is a mixture of M1-type cations and M2-type cations, wherein the M1-type cation is Zn. 2+ Al 3+ Cu 2+ Co 2+ and Sn 2+ One or more of the following; the M2 type cation is Li + Na + K + NH4 + Ca 2+ Mg 2+ One or more of the following, and the molar amount of M1 type cation in the molten salt is 50-100% of the total molar amount of cations in the molten salt, more preferably 55-80%.

6. The method for preparing the siloxane material with controllable surface oxygen composition as described in claim 4, characterized in that, The heat preservation temperature is 80~400℃; the heat preservation time is 8~24h; the inert gas is one or more combinations of nitrogen and argon.

7. The method for preparing the siloxane material with controllable surface oxygen composition as described in claim 4, characterized in that, When the layered silicon alloy raw material is mixed evenly with molten salt, the process also includes grinding the mixture of the layered silicon alloy raw material and molten salt into powder.

8. The method for preparing a siloxane material with controllable surface oxygen composition as described in claim 4, characterized in that, The dilute acid solution is one of dilute hydrochloric acid, dilute sulfuric acid, dilute oxalic acid, dilute nitric acid, dilute perchloric acid, dilute hypochlorous acid, dilute phosphoric acid, dilute acetic acid, etc.; the pH value of the dilute acid solution is 0 ≤ pH < 7.

9. Negative electrode, characterized in that, The active material of the negative electrode includes the siloxane material as described in any one of claims 1 to 3 or the siloxane material prepared by the preparation method as described in any one of claims 4 to 8.

10. A lithium-ion battery, characterized in that, Includes the negative electrode as described in claim 9.

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