Silicon-based negative electrode slurry, preparation method thereof, negative electrode plate and application

Abstract

The invention provides silicon-based negative electrode slurry and a preparation method thereof, a negative electrode plate and application, and belongs to the technical field of battery materials, the silicon-based negative electrode slurry comprises a pre-lithiated siloxy material, a conductive agent, a binder, maleic acid and a solvent; the mass of the maleic acid is 2.57%-11% of the mass of the pre-lithiated siloxy material. By introducing the maleic acid with a specific content, the reaction of silicon and hydroxyl can be reduced to inhibit hydrogen production, and the situation that the uniformity and stability of the slurry are damaged by excessive hydrogen is avoided; and secondly, chemical reaction with active groups on the surface of the pre-lithiated siloxy material can be carried out to form stable chemical bonds to generate a steric hindrance effect, so that aggregation of the silicon-based negative electrode material is prevented, the viscosity of the slurry is reduced, and the uniformity and stability of the slurry are improved. In addition, due to the introduction of maleic acid, the peel strength of the negative pole piece can be remarkably improved, and the battery performance is also remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of battery materials technology, specifically relating to a silicon-based negative electrode slurry, its preparation method, negative electrode sheet, and its application. Background Technology

[0002] With the increasing global demand for new energy sources, batteries, as efficient and clean energy storage and conversion devices, are being used more and more widely. At the same time, the requirements for battery energy density are also increasing. Silicon (Si) anode materials are considered ideal anode materials for next-generation lithium-ion batteries due to their high theoretical capacity (4200 mAh / g) and environmental friendliness. However, Si anode materials suffer from severe volume expansion (300%) and shrinkage during charge and discharge, which leads to damage to the electrode structure and a decrease in battery performance. In contrast, silicon-oxygen materials offer better cycle performance, but have a low initial coulombic efficiency (below 20%). This means that more than 20% of the active lithium is consumed for SEI film formation during the first charge, significantly reducing the actual cycle capacity of the battery. Currently, the most effective method to improve the initial coulombic efficiency of silicon-oxygen materials is pre-lithiation. However, during the mixing process of pre-lithiated silicon-oxygen materials, problems such as gas generation and strong alkali often arise, resulting in poor uniformity and stability of the slurry, thus affecting battery performance.

[0003] To address the aforementioned issues, existing technologies typically employ methods such as adding conductive agents, binders, and surfactants to improve the performance of pre-lithium siloxy anode slurries. Furthermore, some studies have explored improving the electrochemical performance of pre-lithium siloxy anode materials by altering their structure or surface properties.

[0004] Despite some progress in existing technologies, effective solutions have yet to be found for the gas generation and strong alkali issues during the mixing process of pre-lithium siloxy anode materials. Secondly, existing solutions may introduce new problems; for example, adding certain additives may affect the purity and stability of the silicon-based anode material, thus impacting its electrochemical performance. Finally, existing solutions may increase battery manufacturing costs, hindering large-scale battery application.

[0005] Therefore, how to solve the problems of gas generation and strong alkali in the mixing process of pre-lithiated silicon-oxygen materials in a low-cost manner, and thus improve the electrochemical performance of the anode material, is a key research direction that urgently needs to be addressed. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a silicon-based anode slurry, its preparation method, anode sheet, and applications. The present invention introduces a specific amount of maleic acid into the silicon-based anode slurry. Maleic acid neutralizes the strong alkali generated during the preparation of the silicon-based anode slurry, thereby reducing the reaction between silicon and hydroxide ions to suppress hydrogen production and prevent excessive hydrogen gas from damaging the uniformity and stability of the slurry. Secondly, maleic acid can also chemically react with the active groups on the surface of the pre-lithiated silicon-oxygenated material to form stable chemical bonds, generating a steric hindrance effect, thereby preventing the aggregation of the silicon-based anode material, reducing the viscosity of the slurry, and improving the uniformity and stability of the slurry. Therefore, it can act as a dispersant to improve the dispersibility of the slurry. Furthermore, the introduction of maleic acid can significantly improve the peel strength of the prepared anode sheet. In summary, the introduction of maleic acid can effectively improve the uniformity and stability of the silicon-based anode slurry, resulting in a significant improvement in battery performance. Moreover, the introduction cost is low, and the application prospects are promising.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a silicon-based anode slurry, the silicon-based anode slurry comprising a pre-lithiated siloxy-based material, a conductive agent, a binder, maleic acid, and a solvent; wherein the mass of the maleic acid is 2.57%-11% of the mass of the pre-lithiated siloxy-based material.

[0009] As a preferred embodiment of the silicon-based anode slurry of the present invention, the solid content of the silicon-based anode slurry is 54.5%-57.5%.

[0010] Preferably, the pH value of the silicon-based anode slurry is 8-9.5.

[0011] As a preferred technical solution for the silicon-based anode slurry of the present invention, the viscosity of the silicon-based anode slurry is 8000cP-25000cP.

[0012] Preferably, the silicon-based anode slurry has a fineness of 27.5 μm-30 μm.

[0013] As a preferred embodiment of the silicon-based anode slurry of the present invention, the silicon-based anode slurry further includes graphite material.

[0014] Preferably, based on the total mass of the pre-lithiated silica-oxygenated material, graphite material, conductive agent, binder, and maleic acid, the mass content of the pre-lithiated silica-oxygenated material is 6%-10%, the mass content of the graphite material is 90%-95%, the mass content of the conductive agent is 0.5%-2.5%, and the mass content of the binder is 2%-5%.

[0015] As a preferred technical solution for the silicon-based anode slurry of the present invention, the particle size D50 of the pre-lithiated silicon-oxygenated material is 5μm-10μm.

[0016] Preferably, the lithium content of the pre-lithiated silicon-oxygenated material is 6wt%-10wt%.

[0017] As a preferred technical solution for the silicon-based negative electrode slurry of the present invention, the conductive agent includes any one or a combination of at least two of ethyl black, carbon black, artificial graphite or carbon nanotubes.

[0018] Preferably, the adhesive comprises any one or a combination of at least two of polyacrylic acid, sodium carboxymethyl cellulose, or styrene-butadiene rubber.

[0019] Preferably, the solvent includes water. In a second aspect, the present invention provides a method for preparing a silicon-based anode slurry as described in the first aspect, the method comprising the following steps:

[0020] The silicon-based anode slurry is obtained by mixing pre-lithiated silicon-oxygenated material, conductive agent, binder and maleic acid in a solvent.

[0021] As a preferred technical solution for the silicon-based anode slurry of the present invention, the preparation method includes the following steps:

[0022] The pre-lithiated silicon-oxygenated material, graphite material, and conductive agent are mixed, and then sodium carboxymethyl cellulose is added. The mixture is then diluted with deionized water, and maleic acid is added. The mixture is stirred at a speed of 1000-2000 rpm to make the pH of the solvent 8-9.5. Polyacrylic acid and styrene-butadiene rubber are then added and mixed evenly to obtain the silicon-based negative electrode slurry.

[0023] Thirdly, the present invention provides a negative electrode sheet, which is prepared by the silicon-based negative electrode slurry described in the first aspect on a negative electrode current collector.

[0024] Preferably, the peel strength of the negative electrode sheet is 0.9N-1N.

[0025] Fourthly, the present invention provides a lithium-ion battery, the lithium-ion battery comprising the negative electrode sheet as described in the third aspect.

[0026] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) This invention introduces a specific amount of maleic acid into the silicon-based anode slurry. Maleic acid can neutralize the strong alkali generated during the preparation of the silicon-based anode slurry, thereby reducing the reaction between silicon and hydroxide ions to inhibit hydrogen production, lowering the pH value of the slurry, and preventing excessive hydrogen from damaging the uniformity and stability of the slurry. Secondly, maleic acid can also react chemically with the active groups on the surface of the pre-lithiated silicon-oxygenated material to form stable chemical bonds, generating a steric hindrance effect, thereby preventing the aggregation of the silicon-based anode material, reducing the viscosity of the slurry, and improving the uniformity and stability of the slurry. Therefore, it can act as a dispersant to improve the dispersibility of the slurry. Finally, maleic acid is volatile and will not introduce new impurities; therefore, the introduction of maleic acid will not affect the purity and electrochemical performance of the anode sheet. Furthermore, the introduction of maleic acid can significantly improve the peel strength of the prepared anode sheet. In summary, the introduction of maleic acid can not only effectively improve the uniformity and stability of silicon-based anode slurry, thus significantly improving battery performance, but also has little impact on battery manufacturing costs, which is conducive to the large-scale application of batteries.

[0029] (2) This invention has broad application prospects in the future battery manufacturing and R&D fields. Attached Figure Description

[0030] Figure 1 This is a comparison of the viscosity of silicon-based anode slurries prepared in Examples 1-2 and Comparative Examples 1-2 of this invention over time.

[0031] Figure 2 This is a comparison chart showing the fineness test results of the silicon-based anode slurries prepared in Examples 1-2 and Comparative Examples 1-2 after being left to stand for 0 hours.

[0032] Figure 3 The image shows a comparison of the fineness of the silicon-based anode slurries prepared in Examples 1-2 and Comparative Examples 1-2 after being left to stand for 2 hours.

[0033] Figure 4 This is a comparison chart showing the fineness test results of the silicon-based anode slurries prepared in Examples 1-2 and Comparative Examples 1-2 of this invention after being left to stand for 4 hours.

[0034] Figure 5 This is a comparison diagram of the peeling test of the negative electrode sheets prepared in Examples 1-2 and Comparative Examples 1-2 of this invention. Detailed Implementation

[0035] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in conjunction with specific embodiments. In this invention, unless otherwise specified, all parts and percentages are units of mass, and the equipment and raw materials used are commercially available or commonly used in the art. Unless otherwise specified, the methods in the following embodiments are conventional methods in the art.

[0037] The terms “comprising,” “including,” “comprising,” or any other variations thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0038] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1-5” is disclosed, the described range should be interpreted as including ranges “1-4”, “1-3”, “1-2”, “1-2 and 4-5”, “1-3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0039] In one specific embodiment, the present invention provides a silicon-based anode slurry, the silicon-based anode slurry comprising a pre-lithiated siloxy material, a conductive agent, a binder, maleic acid, and a solvent;

[0040] The mass of the maleic acid is 2.57%-11% of the mass of the pre-lithiated silica-oxygenated material.

[0041] This invention introduces a specific amount of maleic acid into a silicon-based anode slurry. Maleic acid neutralizes the strong alkali generated during the preparation of the slurry, thereby reducing the reaction between silicon and hydroxide ions to inhibit hydrogen production, lowering the pH value of the slurry, and preventing excessive hydrogen production from damaging the slurry's uniformity and stability. Secondly, maleic acid can chemically react with the active groups on the surface of the pre-lithiated silicon-oxygenated material to form stable chemical bonds, creating a steric hindrance effect that prevents the aggregation of the silicon-based anode material, reduces the slurry viscosity, and improves the slurry's uniformity and stability. Therefore, it can act as a dispersant to improve the slurry's dispersibility. Finally, maleic acid is volatile and does not introduce new impurities; therefore, its introduction does not affect the purity and electrochemical performance of the anode sheet. Furthermore, the introduction of maleic acid significantly improves the peel strength of the prepared anode sheet. In summary, the introduction of maleic acid not only effectively improves the uniformity and stability of the silicon-based anode slurry, significantly improving battery performance, but also has little impact on battery manufacturing costs, which is beneficial for the large-scale application of batteries.

[0042] In this invention, the mass of maleic acid is 2.57%-11% of the mass of the pre-lithiated siloxy-based material, for example, it can be 2.6%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or 11%, etc.

[0043] In this invention, if the mass of maleic acid is too small, it will be difficult to reduce the viscosity of the slurry and the peel strength of the prepared electrode will be poor; if the mass of maleic acid is too large, the pH of the slurry will be too low, the peel strength of the prepared electrode will be poor, and the electrochemical performance will be poor.

[0044] Furthermore, the solid content of the silicon-based anode slurry is 54.5%-57.5%, for example, it can be 54.5%, 55.5%, 56.5% or 57.5%, etc.

[0045] In this invention, the introduction of maleic acid does not significantly affect the solid content of the silicon-based anode slurry.

[0046] Furthermore, the pH value of the silicon-based negative electrode slurry is 8-9.5, for example, it can be 8, 8.5, 9, 7, or 9.5, etc.

[0047] In this invention, the introduction of maleic acid can neutralize the strong alkali generated during the preparation of silicon-based anode slurry, resulting in a slurry pH of 8-9.5, which is much lower than the pH of slurries in the prior art (i.e., 10-11). This effectively avoids the generation of excessive hydrogen gas that could damage the uniformity and stability of the slurry.

[0048] Furthermore, the viscosity of the silicon-based anode material is 8000 cP-25000 cP, for example, it can be 8000 cP, 10000 cP, 15000 cP, 20000 cP or 25000 cP, etc.

[0049] In this invention, the introduction of maleic acid helps to reduce the viscosity of the slurry.

[0050] Furthermore, the fineness of the silicon-based anode slurry is 27.5-30 μm, for example, it can be 27.5 μm, 28 μm, 28.5 μm, 29 μm, 29.5 μm, or 30 μm, etc.

[0051] In this invention, the introduction of maleic acid helps to improve the fineness of silicon-based anode slurry and enhance the uniformity and stability of the slurry.

[0052] Furthermore, the silicon-based anode slurry also includes graphite material. For example, it could be artificial graphite, etc.

[0053] Furthermore, based on the total mass of the pre-lithiated silicon-oxygen material, graphite material, conductive agent, binder, and maleic silicon-based negative electrode slurry, the mass content of the pre-lithiated silicon-oxygen material is 6%-10%, for example, 6%, 7%, 8%, 9%, or 10%, etc.; the mass content of the graphite material is 90%-95%, for example, 90%, 91%, 92%, 93%, 94%, or 95%, etc.; the mass content of the conductive agent is 0.5%-2.5%, for example, 0.5%, 1%, 1.5%, 2%, or 2.5%, etc.; and the mass content of the binder is 2%-5%, for example, 2%, 3%, 4%, or 5%, etc.

[0054] In this invention, graphite material is added to the slurry to mix with silicon-oxygen materials to achieve the capacity design and improve the cycle stability of the battery.

[0055] Furthermore, the particle size D50 of the pre-lithiated silicon-oxygen material is 5μm-10μm, for example, it can be 5μm, 6μm, 7μm, 8μm, 9μm or 10μm, etc. Furthermore, the lithium content of the pre-lithiated silicon-oxygen material is 6wt%-10wt%, for example, it can be 6wt%, 7wt%, 8wt%, 9wt% or 10wt%, etc.

[0056] Furthermore, the pre-lithiated silicon-oxygen material includes a pre-lithiated silicon-carbon material.

[0057] Furthermore, the conductive agent includes any one or a combination of at least two of acetylene black, carbon black, artificial graphite, or carbon nanotubes.

[0058] Furthermore, the adhesive comprises any one or a combination of at least two of polyacrylic acid, sodium carboxymethyl cellulose, or styrene-butadiene rubber.

[0059] Furthermore, the solvent includes water.

[0060] In another specific embodiment, the present invention provides a method for preparing the silicon-based anode paste as described above, the method comprising the following steps:

[0061] The silicon-based anode slurry is obtained by mixing pre-lithiated silicon-oxygenated material, conductive agent, binder and maleic acid in a solvent.

[0062] It should be noted that the present invention does not limit the pre-lithiation technology of pre-lithiated silicon-oxygen materials. For example, it can be a chemical pre-lithiation method, an electrochemical pre-lithiation method, or an additive pre-lithiation method. Among them, chemical pre-lithiation can be divided into two types: mechanical alloying method and solution pre-lithiation method. The former mainly involves ball milling / stirring the molten lithium metal with the active material under the protection of an inert gas to achieve pre-lithiation. The latter utilizes the mixing of pre-lithiation solution with the active material to achieve pre-lithiation.

[0063] Furthermore, the preparation method includes the following steps:

[0064] The pre-lithiated silicon-oxygenated material, graphite material, and conductive agent are mixed, and then sodium carboxymethyl cellulose is added. The mixture is then diluted with deionized water, and maleic acid is added. The mixture is stirred at a speed of 1000-2000 rpm (e.g., 1000 rpm, 1500 rpm, or 2000 rpm) to adjust the pH of the solution to 8-9.5. Polyacrylic acid and styrene-butadiene rubber are then added and mixed evenly to obtain the silicon-based negative electrode slurry.

[0065] In another specific embodiment, the present invention provides a negative electrode sheet, which is prepared by the silicon-based negative electrode material described in the first aspect on a negative electrode current collector.

[0066] Furthermore, the peel strength of the negative electrode sheet is 0.9N-1N, for example, it can be 0.9N, 0.95N or 1N.

[0067] In another specific embodiment, the present invention provides a method for preparing a negative electrode sheet, the method comprising the following steps:

[0068] A silicon-based negative electrode slurry is coated onto a negative electrode current collector, and the negative electrode sheet is obtained after drying.

[0069] Furthermore, the drying temperature is 70℃-100℃, for example, it can be 70℃, 80℃, 90℃ or 100℃, etc.

[0070] Furthermore, the drying time is 12h-24h, for example, it can be 12h, 16h, 20h or 24h.

[0071] In another specific embodiment, the present invention provides a lithium-ion battery, the lithium-ion battery comprising the negative electrode sheet as described above.

[0072] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments are merely illustrative of the present invention and should not be construed as limiting the invention.

[0073] Example 1

[0074] This embodiment provides a silicon-based anode slurry, which includes a pre-lithiated siloxy material, a graphite material, a conductive agent, a binder, maleic acid, and a solvent.

[0075] The mass of maleic acid is 2.57 wt% of the mass of the pre-lithiated silica-oxygenated material;

[0076] The silicon-based anode slurry has a solid content of 57.5%; a pH value of 9.4; a viscosity of 21589 cP; and a fineness of 30 μm.

[0077] Based on the total mass of the pre-lithiated silica-oxygenated material, graphite material, conductive agent, binder, and maleic acid, the mass content of the pre-lithiated silica-oxygenated material is 9.5%, the mass content of the conductive agent is 2.5%, the mass content of the binder is 2.5%, and the mass content of the graphite material is 85.5%.

[0078] The pre-lithiated silicon-oxygen material has a particle size D50 of 8 μm, a lithium content of 8 wt%, and is a pre-lithiated silicon-carbon material.

[0079] The conductive agent is acetylene black, the adhesive includes sodium carboxymethyl cellulose and styrene-butadiene rubber, the solvent is deionized water, and the graphite material shown is artificial graphite.

[0080] This embodiment also provides a method for preparing the above-mentioned silicon-based anode paste, the preparation method comprising the following steps:

[0081] The pre-lithiated silicon-oxygenated material, graphite material, and conductive agent were mixed, and then sodium carboxymethyl cellulose was added. The mixture was then diluted with deionized water, and 0.3 g of maleic acid was added. The mixture was stirred at 1500 rpm to make the pH of the solution 9.4. Styrene-butadiene rubber was then added and mixed evenly to obtain the silicon-based negative electrode slurry.

[0082] This embodiment also provides a negative electrode sheet, wherein the silicon-based negative electrode material is prepared by the above-mentioned silicon-based negative electrode slurry on a negative electrode current collector, and the preparation method of the silicon-based negative electrode material includes:

[0083] The silicon-based negative electrode slurry was coated onto the copper foil of the negative electrode current collector and dried at 110°C for 24 hours to obtain the negative electrode sheet.

[0084] Example 2

[0085] The difference between this embodiment and Embodiment 1 is that the amount of maleic acid added is 0.8g, so that the mass of maleic acid is 6.87% of the mass of the pre-lithiated siloxy material.

[0086] The remaining preparation methods and parameters are consistent with those in Example 1.

[0087] Comparative Example 1

[0088] The difference between this comparative example and Example 1 is that the amount of maleic acid added is 3g, so that the mass of maleic acid is 25.77% of the mass of the pre-lithiated siloxy material.

[0089] The remaining preparation methods and parameters are consistent with those in Example 1.

[0090] Comparative Example 2

[0091] The difference between this comparative example and Example 1 is that maleic acid is not added to the silicon-based anode slurry.

[0092] The remaining preparation methods and parameters are consistent with those in Example 1.

[0093] Figure 1 The graph shows a comparison of the viscosity of silicon-based anode slurries prepared in Examples 1-2 and Comparative Examples 1-2 over time. As can be seen from the graph, the introduction of maleic acid helps to reduce the viscosity of the slurry, and the viscosity of the slurry with maleic acid introduced does not change drastically within a time span of 4 hours.

[0094] Figure 2 , Figure 3 and Figure 4 The figures show a comparison of the fineness of the silicon-based anode slurries prepared in Examples 1-2 and Comparative Examples 1-2 after 0h, 2h, and 4h of storage. The figures show that the introduction of maleic acid helps reduce the fineness of the slurry, improves its dispersion and stability, and the particle size of the slurry does not change significantly within 4h.

[0095] Figure 5 The figures show a comparison of the peel strength of the negative electrode sheets prepared in Examples 1-2 and Comparative Examples 1-2. As can be seen from the figures, when the mass of maleic acid is 2.57% of the mass of the pre-lithiated siloxy material, the prepared electrode sheet has excellent peel strength, which can reach 1N.

[0096] Performance testing

[0097] I. The slurry and negative electrode sheet provided in the above embodiments and comparative examples were tested, and the specific test results are shown in Table 1.

[0098] Table 1

[0099]

[0100] analyze:

[0101] As shown in the table above, the introduction of maleic acid into the silicon-based anode slurry in this invention helps to reduce the viscosity of the slurry and improve the peel strength of the electrode. The overall effect is optimal when the mass of maleic acid is 2.57% of the mass of the pre-lithiated silicon-oxygenated material.

[0102] 2. The negative electrode sheets provided in the above embodiments and comparative examples are used to make lithium-ion batteries, and the prepared lithium-ion batteries are subjected to charge-discharge tests and impedance tests.

[0103] The charging and discharging test conditions are: 0.1C / 0.1C, 1.5V-0.005V.

[0104] The test results are shown in Table 2.

[0105] Table 2

[0106]

[0107] analyze:

[0108] As can be seen from the above, as the amount of maleic acid added increases, the specific capacity of the battery gradually decreases. When the mass of maleic acid is 2.57% of the mass of the pre-lithiated siloxy material, the specific capacity of the battery is close to that of the battery without maleic acid.

[0109] In summary, introducing a specific amount of maleic acid into the silicon-based anode slurry can lower the slurry's pH value and chemically react with the active groups on the surface of the pre-lithiated silicon-oxygenated material to form stable chemical bonds, thereby generating a steric hindrance effect. This prevents the aggregation of the silicon-based anode material, reduces the slurry viscosity, and improves the slurry's uniformity and stability. Furthermore, the introduction of maleic acid significantly improves the peel strength of the prepared anode sheet. The above investigation shows that when the mass of maleic acid is 2.57% of the pre-lithiated silicon-oxygenated material, the overall performance of the prepared slurry, anode sheet, and battery is optimal, with minimal impact on battery manufacturing costs, which is beneficial for large-scale battery application.

[0110] The applicant declares that the technical solution of this invention is illustrated by the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the product of this invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

Claims

1. A silicon-based anode paste, characterized in that, The silicon-based anode slurry includes pre-lithiated siloxy materials, conductive agents, binders, maleic acid, and solvents. The mass of the maleic acid is 2.57%-11% of the mass of the pre-lithiated silica-oxygenated material.

2. The silicon-based anode paste according to claim 1, characterized in that, The solid content of the silicon-based anode slurry is 54.5%-57.5%; The pH value of the silicon-based anode slurry is 8-9.

5.

3. The silicon-based anode paste according to claim 1, characterized in that, The viscosity of the silicon-based negative electrode slurry is 8000 cP-25000 cP; The silicon-based anode slurry has a fineness of 27.5 μm-30 μm.

4. The silicon-based anode paste according to claim 1, characterized in that, The silicon-based anode slurry also includes graphite materials; Based on the total mass of the pre-lithiated silica-oxygenated material, graphite material, conductive agent, binder, and maleic acid, the mass content of the pre-lithiated silica-oxygenated material is 6%-10%, the mass content of the graphite material is 90%-95%, the mass content of the conductive agent is 0.5%-2.5%, and the mass content of the binder is 2%-5%.

5. The silicon-based anode paste according to claim 1, characterized in that, The particle size D50 of the pre-lithiated silicon-oxygenated material is 5μm-10μm; The lithium content of the pre-lithiated silicon-oxygenated material is 6wt%-10wt%.

6. The silicon-based anode paste according to claim 1, characterized in that, The conductive agent includes any one or a combination of at least two of ethyl black, carbon black, artificial graphite, or carbon nanotubes. The adhesive comprises any one or a combination of at least two of polyacrylic acid, sodium carboxymethyl cellulose, or styrene-butadiene rubber. The solvent includes water.

7. A method for preparing a silicon-based negative electrode paste as described in any one of claims 1-6, characterized in that, The preparation method includes the following steps: The silicon-based anode slurry is obtained by mixing pre-lithiated silicon-oxygenated material, conductive agent, binder and maleic acid in a solvent.

8. The preparation method according to claim 7, characterized in that, The preparation method includes the following steps: The pre-lithiated silicon-oxygenated material, graphite material, and conductive agent are mixed, and then sodium carboxymethyl cellulose is added. The mixture is then diluted with deionized water, and maleic acid is added. The mixture is stirred at a speed of 1000-2000 rpm to make the pH of the solution 8-9.

5. Polyacrylic acid and styrene-butadiene rubber are then added and mixed evenly to obtain the silicon-based negative electrode paste.

9. A negative electrode sheet, characterized in that, The negative electrode sheet is prepared on a negative electrode current collector by the silicon-based negative electrode slurry according to any one of claims 1-6; The peel strength of the negative electrode sheet is 0.9N-1N.

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

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