A silicon anode binder, its preparation method and application

Abstract

This invention discloses a silicon anode binder, its preparation method, and its applications. The invention uses a short-chain polycarboxylic acid as a crosslinking agent, which has flexible orientation and dense active centers. It bridges the gap between flexible water-soluble polysaccharides and rigid polyaniline molecular chains through covalent ester bonds and non-covalent hydrogen bonds, constructing a three-dimensional network structure binder with multi-gradient energy dissipation. When applied to silicon anodes in lithium-ion batteries, it can significantly improve structural stability and electrode reaction kinetics. Batteries prepared using the binder and functionalized silicon of this invention exhibit high discharge capacity, superior rate performance, and good cycle stability.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery materials technology, and in particular to a silicon anode binder, its preparation method, and its application. Background Technology

[0002] Among numerous electrochemical energy storage and conversion devices, lithium-ion batteries are highly favored due to their high energy density and long cycle life, and are widely used in portable electronic devices and electric vehicles. However, the theoretical capacity of traditional graphite anodes is limited, making it difficult to meet the growing demand for high-energy-density devices. Therefore, there is an urgent need to develop advanced anode materials for next-generation batteries. Silicon anodes, in particular, are favored due to their ultra-high specific capacity (Li₂ / Li₃). 15 Si4 (3579 mAh / g), abundant in the Earth's crust (second highest elemental abundance), and low delithiation potential (~0.4 V vs Li / Li). + Silicon has broad application prospects in high-energy-density batteries. However, during charge and discharge, silicon undergoes huge volume deformation (>300%), leading to electrode structure shattering, which in turn causes rapid capacity decay and reduced cycle life. Simultaneously, silicon's low conductivity results in sluggish electrode reaction dynamics, leading to poor rate performance under high-current charge and discharge. These defects severely limit the further application of silicon materials in the energy storage field.

[0003] Although the binder constitutes a small portion of the electrode components, it plays a crucial role in the structural stability of the electrode. Polyvinylidene fluoride (PVDF) is a commonly used binder in lithium-ion batteries, exhibiting good adhesion; however, the weak van der Waals forces formed with the silicon surface alone are insufficient to provide stable cycle performance. Carboxymethyl cellulose (CMC) contains polar groups, enhancing bonding strength through covalent bonding with silicon; however, its viscosity is low and it is brittle, making it difficult to withstand the large volume deformation of silicon. The one-dimensional configuration of these binders fundamentally limits their interaction with the silicon surface. Grafted polymers, such as polyacrylic acid-carboxymethyl cellulose binders, are considered to provide more contact points, which is beneficial for stress dispersion; however, due to the lack of interchain connections, polymer chain slippage still occurs during volume expansion, which is detrimental to maintaining the long-term stability of the electrode. Therefore, it is necessary to construct network-like binders to provide multiple interchain connections to enhance mechanical properties. Furthermore, since most binders are non-conductive components, and silicon itself has poor conductivity, grafting conductive components into the binder can effectively improve the electrochemical reaction kinetics of silicon. Meanwhile, the interfacial interaction between the binder and the active material is also crucial. Therefore, developing binders with multifunctional network structures for use in surface-functionalized active materials is of significant research value. Summary of the Invention

[0004] This invention aims to at least solve one of the aforementioned technical problems existing in the prior art. Therefore, the object of this invention is to provide a supramolecular self-assembled silicon anode binder with good mechanical strength and viscosity, which can improve electron transport efficiency and electrode structural stability during the electrode reaction process. To achieve the above objective, the technical solution adopted by this invention is as follows:

[0005] The first aspect of the present invention provides a silicon anode binder.

[0006] A second aspect of the present invention provides a method for preparing a silicon anode binder.

[0007] A third aspect of the present invention provides a silicon anode material.

[0008] A fourth aspect of the present invention provides a method for preparing a silicon anode material.

[0009] The fifth aspect of the present invention proposes the application of a silicon anode binder.

[0010] According to a first aspect of the present invention, a silicon anode binder is provided, the silicon anode binder comprising: a water-soluble polymeric polysaccharide, a crosslinking agent and polyaniline, wherein the water-soluble polymeric polysaccharide and polyaniline are connected by the crosslinking agent to form a three-dimensional network structure.

[0011] In some embodiments of the present invention, the water-soluble high molecular weight polysaccharide is at least one of sodium alginate, xanthan gum, starch, gum arabic, and guar gum.

[0012] In some embodiments of the present invention, the crosslinking agent is a short-chain polycarboxylic organic acid.

[0013] In some preferred embodiments of the present invention, the crosslinking agent is at least one of citric acid, malic acid, and tartaric acid.

[0014] In this invention, short-chain polycarboxylic organic acids are used as crosslinking agents. These agents have flexible orientation and dense active centers. Through covalent ester bonds and non-covalent hydrogen bonds, a three-dimensional network structure with multi-gradient energy dissipation is constructed between flexible water-soluble polysaccharides and rigid polyaniline molecular chains.

[0015] In some preferred embodiments of the present invention, the polyaniline has a linear molecular configuration.

[0016] In this invention, polyaniline with a linear molecular configuration is selected because the molecular structures of cross-linked and star-shaped polyaniline are complex and not conducive to the uniform dispersion and bonding of various components in the binder system. In particular, linear polyaniline is selected because the regular linear chains can form a uniform multi-gradient energy dissipation binder network system with high molecular weight polysaccharides under the construction of small molecule cross-linking agents, thereby improving mechanical properties and viscosity.

[0017] According to a second aspect of the present invention, a method for preparing the silicon anode binder described in the first aspect is provided, comprising: mixing and reacting a water-soluble polymeric polysaccharide solution with a crosslinking agent, then adding a polyaniline suspension while stirring, and sonicating to obtain the silicon anode binder.

[0018] In some embodiments of the present invention, the concentration of water-soluble polysaccharides in the water-soluble polysaccharide solution is 10-15 g / L.

[0019] In some embodiments of the present invention, the concentration of the crosslinking agent is 5 to 10 g / L.

[0020] In some embodiments of the present invention, the concentration of polyaniline in the polyaniline suspension is 10-15 g / L.

[0021] In some preferred embodiments of the present invention, the mass ratio of the water-soluble polymeric polysaccharide, crosslinking agent and polyaniline is 4-7:1:2-5, preferably 4.5-6:1:3-4.5.

[0022] In some embodiments of the present invention, the stirring speed is 600-1500 rpm; the purpose is to enable the carboxyl group in the crosslinking agent molecule and the hydroxyl group of the water-soluble polymer polysaccharide to form a strong covalent ester bond, thereby anchoring it to the water-soluble polymer polysaccharide molecular chain.

[0023] In some embodiments of the present invention, the mixing reaction time is 0.5 to 3 hours and the temperature is 40 to 80°C; preferably, the mixing reaction time is 0.5 to 1 hour and the temperature is 40 to 50°C.

[0024] In some embodiments of the present invention, the ultrasound time is 1 to 5 hours; the purpose is to allow the polyaniline molecules to undergo supramolecular self-assembly with the product after the mixing reaction to obtain the silicon anode binder; the ultrasound time is preferably 2 to 3 hours.

[0025] In some preferred embodiments of the present invention, the preparation of the water-soluble polymeric polysaccharide solution includes: mixing the water-soluble polymeric polysaccharide with deionized water, heating in a water bath and stirring; the heating temperature is 50-90°C, the stirring speed is 800-1200 rpm, and the time is 2-5 hours.

[0026] A third aspect of the present invention provides a silicon anode material comprising surface-functionalized silicon powder, the silicon anode binder described in the first aspect, and a conductive agent.

[0027] In some embodiments of the present invention, the silicon anode material further includes a current collector.

[0028] In some embodiments of the present invention, the current collector is a metal foil.

[0029] In some embodiments of the present invention, the surface-functionalized silicon powder is surface-hydroxylated silicon powder.

[0030] In some embodiments of the present invention, the conductive agent is at least one of acetylene black, carbon fiber, carbon nanotubes, and super P.

[0031] In some embodiments of the present invention, the mass ratio of the surface-functionalized silicon powder, the silicon anode binder, and the conductive agent is (6-9):(0.5-2):(0.5-1).

[0032] In some more preferred embodiments of the present invention, the mass ratio of the surface-functionalized silicon powder, silicon anode binder and conductive agent is one of 7:2:1, 8:1:1, 6:3:1, and 9:0.5:0.5.

[0033] According to a fourth aspect of the present invention, a method for preparing the silicon anode material described in the third aspect is provided, comprising:

[0034] The surface-functionalized silicon powder, silicon anode binder, and conductive agent are mixed in deionized water according to the stated mass ratio to form a slurry, which is then coated onto the current collector and dried to obtain the silicon anode material.

[0035] In some embodiments of the present invention, the coating loading is 0.5–3.0 mg / cm³. 2 Preferably 0.5–1 mg / cm³ 2 .

[0036] In some embodiments of the present invention, the drying method is one or a combination of vacuum drying and forced air drying, and the drying temperature is 60-120°C and the time is 6-24 hours.

[0037] In some embodiments of the present invention, the surface-functionalized silicon powder is prepared as follows: silicon powder is mixed with a mixed solution of H2SO4 and H2O2, reacted, washed and dried to obtain the silicon powder; the average particle size of the silicon powder is 50 nm to 3 μm; the volume ratio of H2SO4 to H2O2 is 1 to 5:1; the concentration of H2SO4 is 98% and the concentration of H2O2 is 30%; the temperature of the mixing reaction is 60 to 120 °C and the time is 0.5 to 12 h.

[0038] According to a fifth aspect of the present invention, the application of the silicon anode binder described in the first aspect in the preparation of a battery is proposed.

[0039] The beneficial effects of this invention are:

[0040] The adhesive of this invention uses water-soluble polysaccharides with high viscosity and good flexibility, and conductive polyaniline as the main raw materials. Short-chain polycarboxylic acid is used as a crosslinking agent, bridging the molecular chains of the water-soluble polysaccharide and linear polyaniline simultaneously through strong covalent ester bonds and reversible non-covalent hydrogen bonds, achieving effective bonding of different functional components at the molecular level. The prepared adhesive exhibits good mechanical properties and viscosity.

[0041] A novel three-dimensional network binder was prepared by using a supramolecular self-assembly strategy to prepare silicon for application in silicon anodes after moderate surface functionalization pretreatment with a strong oxidizing solution.

[0042] In the binder system, the -OH and -COOH groups in the water-soluble polymeric polysaccharide and crosslinking agent undergo supramolecular self-assembly with the -OH groups on the functionalized silicon surface, thereby forming a stable bonding interface between the multifunctional binder and the silicon surface, effectively mitigating the expansion effect of the silicon anode. The -COOH group in the crosslinking agent can react with Li... + The binding agent accelerates lithium-ion transport. The abundant polar groups (-OH, -COOH, -NH2, etc.) in the binder system serve as active sites, forming dynamic hydrogen bonds within the binder system and after supramolecular self-assembly between the binder and the silicon surface. These bonds reversibly dissociate and reshape during silicon volume changes, maintaining electrode integrity and electrical contact connectivity. Simultaneously, it achieves strong adhesion of the binder to the silicon interface, shortening the distance the binder diffuses to the dissociation sites and improving the repair response speed. Furthermore, polyaniline further enhances electron transport by N atoms in the binder system during the electrode reaction. The prepared silicon anode exhibits excellent reaction kinetics and structural stability, showing great application potential in lithium-ion battery anode materials. Batteries prepared using the binder and functionalized silicon of this invention exhibit high discharge capacity, superior rate performance, and good cycle stability. Attached Figure Description

[0043] Figure 1 This is a cyclic voltammetry diagram of a button cell assembled from the silicon negative electrode sheet prepared in Example 1 of the present invention.

[0044] Figure 2 This is a constant current charge-discharge diagram of a button cell assembled from the silicon negative electrode sheet prepared in Example 1 of the present invention.

[0045] Figure 3 This is a constant current charge-discharge diagram of a button cell assembled from the silicon negative electrode sheet prepared in Example 2 of the present invention.

[0046] Figure 4 This is a constant current charge-discharge diagram of a button cell assembled from the silicon negative electrode sheet prepared in Example 3 of the present invention.

[0047] Figure 5This is a comparison chart of the rate performance of button cells assembled from silicon anode sheets prepared in Example 1, Comparative Example 1, and Comparative Example 2 of the present invention.

[0048] Figure 6 This is a comparison chart of the cycle performance of button batteries assembled from silicon anode sheets prepared in Example 1, Comparative Example 1, and Comparative Example 2 of the present invention.

[0049] Figure 7 This is a comparison chart of the cycle performance of button batteries assembled from silicon anode sheets prepared in Example 1 and Comparative Example 3 of the present invention.

[0050] Figure 8 This is a cycle performance diagram of a button cell assembled from the silicon anode sheet prepared in Comparative Example 4 of this invention.

[0051] Figure 9 This is a cycle performance diagram of a button cell assembled from the silicon anode sheet prepared in Comparative Example 5 of the present invention. Detailed Implementation

[0052] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials, reagents, or apparatus used in the embodiments and comparative examples are all available from conventional commercial sources or can be obtained by existing technical methods. Unless otherwise specified, the test or experimental methods are conventional methods in the art.

[0053] Example 1

[0054] This embodiment prepares a silicon anode binder, and the specific process is as follows:

[0055] (1) Weigh 150 mg of sodium alginate and add it to 15 mL of deionized water. Heat the solution in a water bath at 50 °C and stir magnetically at 1000 rpm for 2 h to dissolve and obtain a 10 g / L sodium alginate solution A.

[0056] (2) Add 3 mL of citric acid solution with a concentration of 10 g / L as a crosslinking agent to solution A and continue stirring at 1000 rpm at 40 °C for 1 h to mix and react, so that the carboxyl group in the crosslinking agent molecule and the hydroxyl group of sodium alginate form a covalent ester bond, thereby anchoring to the sodium alginate molecular chain to obtain solution B.

[0057] (3) 12 mL of linear polyaniline with a concentration of 10 g / L was gradually added dropwise to solution B under stirring, and ultrasonic treatment was performed for 3 h to allow it to undergo supramolecular self-assembly with the above solution B system, thus obtaining silicon anode binder, wherein the mass ratio of sodium alginate, citric acid and polyaniline added was 5:1:4.

[0058] This embodiment also prepares a silicon negative electrode sheet, the specific process of which is as follows:

[0059] 1050 mg of commercial silicon powder with a particle size of 100 nm was dispersed in 30 mL of a mixed strong oxidant with a volume ratio of H2SO4 (98%) / H2O2 (30%) = 2:1. The mixture was functionalized at 80 °C for 3 h to enrich the surface of the silicon particles with -OH groups. The silicon particles were then centrifuged and washed until pH = 7, and then vacuum dried at 80 °C to obtain functionalized silicon powder.

[0060] The functionalized silicon powder, silicon anode binder, and acetylene black were mixed in deionized water at a mass ratio of 7:2:1 and then coated onto copper foil, with the loading controlled at 0.7 mg / cm³. 2 Silicon anode sheets are prepared by vacuum drying at 80℃ for 24 hours.

[0061] Example 2

[0062] This embodiment prepares a silicon anode binder, wherein the mass ratio of sodium alginate, citric acid and polyaniline is 6:1:3, and the remaining specific processes are as described in Example 1.

[0063] The silicon anode sheet was prepared using the lithium battery silicon anode binder of this embodiment, referring to Example 1.

[0064] Example 3

[0065] This embodiment prepares a silicon anode binder for lithium batteries, wherein the ultrasonic time in step (3) is 2 hours, and the rest of the specific process is carried out in accordance with Example 1.

[0066] The silicon anode sheet was prepared using the lithium battery silicon anode binder of this embodiment, referring to Example 1.

[0067] Comparative Example 1

[0068] This comparative example prepared a silicon anode binder, which differs from Example 1 in that steps (2) and (3) are omitted, that is, only sodium alginate is used as the binder. The specific steps are as follows:

[0069] Weigh 150 mg of sodium alginate and add it to 15 mL of deionized water. Heat the solution in a water bath at 50 °C and stir magnetically at 1000 rpm for 2 hours to dissolve it and obtain a 10 g / L sodium alginate solution A, which is the silicon anode binder.

[0070] Silicon anode sheets were prepared using the silicon anode binder of this comparative example, as described in Example 1.

[0071] Comparative Example 2

[0072] This comparative example prepared a silicon anode binder for lithium batteries. The difference from Example 1 is that step (3) is omitted, that is, only sodium alginate and citric acid are used as binders. The specific steps are as follows:

[0073] (1) Weigh 150 mg of sodium alginate and add it to 15 mL of deionized water. Heat the solution in a water bath at 50 °C and stir magnetically at 1000 rpm for 2 h to dissolve and obtain a 10 g / L sodium alginate solution A.

[0074] (2) Add 3 mL of citric acid solution with a concentration of 10 g / L as a crosslinking agent to solution A and continue stirring at 1000 rpm at 40 °C for 1 h to mix and react, so that the carboxyl group in the crosslinking agent molecule and the hydroxyl group of sodium alginate form a covalent ester bond, thereby anchoring to the sodium alginate molecular chain to obtain solution B.

[0075] (3) Mix the above sodium alginate solution A with solution B to obtain silicon anode binder, wherein the mass ratio of sodium alginate to citric acid is 5:1.

[0076] Silicon anode sheets were prepared using the silicon anode binder of this comparative example, as described in Example 1.

[0077] Comparative Example 3

[0078] This comparative example prepared a silicon negative electrode sheet. The difference from Example 1 is that the functionalization step of silicon powder was omitted, and commercial silicon powder was used directly to prepare the electrode.

[0079] Comparative Example 4

[0080] This comparative example prepared a silicon negative electrode sheet, which differs from Example 1 in that it uses polyacrylic acid as a crosslinking agent. Polyacrylic acid is a long-chain organic acid.

[0081] Silicon anode sheets were prepared using the silicon anode binder of this comparative example, as described in Example 1.

[0082] Comparative Example 5

[0083] This comparative example prepared a silicon negative electrode sheet, which differs from Example 1 in that the mixing reaction temperature is 20°C.

[0084] Silicon anode sheets were prepared using the silicon anode binder of this comparative example, as described in Example 1.

[0085] Test case

[0086] Lithium foil was used as the counter electrode and assembled into button cells together with silicon anodes prepared in Examples 1-3 and Comparative Examples 1-5, respectively. Electrochemical tests were then performed on the button cells, which were placed in a 25°C constant temperature chamber during the tests.

[0087] Cyclic voltammetry tests were performed on the coin cells assembled from the silicon anode sheet prepared in Example 1 under the conditions of a potential window of 0.01-2.0V and a scan rate of 0.1mV / s. The results are as follows: Figure 1As shown, it exhibits obvious redox characteristic peaks for Si lithiation and delithiation, indicating that the material has good electrode reaction kinetics. The results of Examples 2 and 3 are similar to those of Example 1 and will not be repeated.

[0088] Constant current charge-discharge tests were conducted on the coin cells assembled from the silicon anode sheet prepared in Example 1 under the conditions of a potential window of 0.01-2.0V and a current density of 1A / g. The results are as follows: Figure 2 As shown, it achieves a specific capacity of 1977 mAh / g. The superior electrochemical performance demonstrates that the silicon anode of this invention can effectively leverage the high capacity advantage of silicon.

[0089] Constant current charge-discharge tests were conducted on the coin cells assembled from the silicon anode sheets prepared in Example 2 under conditions of a potential window of 0.01-2.0V and a current density of 1A / g. Figure 3 As shown, it can achieve a specific capacity of 1966mAh / g.

[0090] Constant current charge-discharge tests were conducted on the coin cells assembled from the silicon anode sheets prepared in Example 3 under conditions of a potential window of 0.01-2.0V and a current density of 1A / g. Figure 4 As shown, it can achieve a specific capacity of 1856mAh / g.

[0091] The rate performance of button cells assembled from the silicon anode sheets prepared in Example 1 and Comparative Examples 1-2 was tested, and the results are as follows: Figure 5 As shown. From Figure 5 It can be seen that in Example 1, the silicon anode exhibits the best rate performance when sodium alginate, citric acid, and linear polyaniline are used as binders, followed by Comparative Example 2, with Comparative Example 1 showing the worst performance. This is mainly due to the abundant carboxyl groups in citric acid, which can bind with lithium ions, enhancing the ion transport rate during the electrochemical reaction. Furthermore, the introduction of the conductive polymer polyaniline can further improve electronic conductivity, resulting in the strongest electrochemical reaction kinetics and thus excellent rate performance.

[0092] The button cells assembled from the silicon anode sheets prepared in Example 1 and Comparative Examples 1-2 were subjected to long-term cycle performance tests, and the results are as follows: Figure 6 As shown. From Figure 6It can be seen that the cycling stability of the silicon anode material in Example 1 was significantly improved, retaining a capacity of 1384 mAh / g after 100 cycles at a current density of 1 A / g. In contrast, the silicon anode materials in Comparative Examples 1 and 2 only retained 868 and 1154 mAh / g, respectively. This indicates that when the binder of Example 1 is applied to the silicon anode, the composite binder, under the influence of strong covalent bonds and reversible hydrogen bonds, synergistically combines the advantages of short chains with rigidity and long chains with flexibility, forming a multi-gradient energy dissipation three-dimensional network structure. This structure can effectively buffer the enormous stress generated by volumetric strain in silicon during cycling, thereby maintaining the integrity of the electrode structure.

[0093] The button cells assembled from the silicon anode sheets prepared in Example 1 and Comparative Example 3 were subjected to long-term cycle performance tests, and the results are as follows: Figure 7 As shown. From Figure 7 It can be seen that the silicon anode material of Comparative Example 3 only retained 500 mAh / g, indicating that the interaction between the silicon surface and the binder in Comparative Example 3 is weak. During cycling, silicon and binder slip, and the interface stability between the two is poor. The binder cannot confine silicon particles and release volume stress, resulting in rapid capacity decay.

[0094] The coin cells assembled from the silicon anode sheets prepared in Comparative Example 4 were subjected to long-term cycle performance tests, and the results are as follows: Figure 8 As shown. From Figure 8 It can be seen that the silicon anode material in Comparative Example 4 only retained 1007 mAh / g, indicating that when the long-chain polyacrylic acid used in Comparative Example 4 was used as a crosslinking agent, the prepared binder could not form a gradient energy dissipation network, thus failing to maintain the structural stability of silicon well. In contrast, when the short-chain polycarboxylic acid was used as a crosslinking agent in Example 1, the crosslinking agent formed a short-range "hard" confinement region, while the water-soluble polymeric polysaccharide formed a long-range "soft" buffer zone, complementing each other. Furthermore, the carboxyl group orientation of the short-chain organic acid is more flexible, allowing it to more effectively combine with the molecular chains of other components in the binder system, constructing a multi-gradient energy dissipation mechanism in the binder system and fully releasing the volumetric stress of silicon.

[0095] The coin cells assembled from the silicon anode sheets prepared in Comparative Example 5 were subjected to long-term cycle performance tests, and the results are as follows: Figure 9 As shown. From Figure 9 It can be seen that the silicon anode material of Comparative Example 5 only retained 810 mAh / g, indicating that the binder of Comparative Example 5 was prepared at a low mixing reaction temperature, and the functional groups in the binder system did not undergo sufficient bonding or molecular self-assembly, thus failing to construct a robust three-dimensional network structure. As a result, the effect of releasing the huge stress generated by silicon during cycling was poor, leading to rapid capacity decay.

[0096] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A silicon anode binder, characterized in that, The silicon anode binder comprises: a water-soluble polymeric polysaccharide, a crosslinking agent, and polyaniline. The water-soluble polymeric polysaccharide and polyaniline are linked by the crosslinking agent to form a three-dimensional network structure. The water-soluble polymeric polysaccharide is at least one of sodium alginate, xanthan gum, starch, gum arabic, and guar gum. The crosslinking agent is a short-chain polycarboxylic acid. The polyaniline has a linear molecular configuration. The silicon anode binder is prepared by a method comprising the following steps: mixing and reacting a water-soluble polymer polysaccharide solution with a crosslinking agent, then adding a polyaniline suspension while stirring, and sonicating to obtain the silicon anode binder; the mixing reaction time is 0.5h to 1h, and the temperature is 40℃ to 50℃; the sonication time is 1h to 5h.

2. The silicon anode binder according to claim 1, characterized in that: The mass ratio of the water-soluble polymer polysaccharide, cross-linking agent and polyaniline is (4-7):1:(2-5).

3. A silicon anode material, characterized in that: It includes surface-functionalized silicon powder, the silicon anode binder and conductive agent as described in claim 1 or 2.

4. The silicon anode material according to claim 3, characterized in that: The mass ratio of the surface-functionalized silicon powder, silicon anode binder, and conductive agent is (6-9):(0.5-2):(0.5-1).

5. The method for preparing the silicon anode material according to claim 3 or 4, characterized in that, include: Surface-functionalized silicon powder, silicon anode binder, and conductive agent are mixed in deionized water in a certain proportion to form a slurry, which is then coated onto a current collector and dried to obtain the silicon anode material.

6. The application of the silicon anode binder according to claim 1 or 2 in the preparation of batteries.

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